CA2158131C - Sulfur dioxide generation using granulated or emulsoid sulfur feedstock - Google Patents
Sulfur dioxide generation using granulated or emulsoid sulfur feedstockInfo
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- CA2158131C CA2158131C CA002158131A CA2158131A CA2158131C CA 2158131 C CA2158131 C CA 2158131C CA 002158131 A CA002158131 A CA 002158131A CA 2158131 A CA2158131 A CA 2158131A CA 2158131 C CA2158131 C CA 2158131C
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Abstract
A system (300) and method for generating sulfur dioxide includes a source (302) of granulated sulfur or emulsoid sulfur. The granulated sulfur or emulsoid sulfur is to a sulfur furnace (322) which combusts the sulfur to generate sulfur dioxide.
Description
w0 94noo14 2 1 5 8 1 3 1 ~ y 1'CTNS94101973 2 OR EMUISOID SULF(JR FEEDSTOCK
3 ..
4 Technical Fief this invention relates to methods and apparatuses for generating gas~us 6 sulfur dioxide by combusting sulfur) and more particularly, to a method and 7 apparatus for generating gaseous sulfur dioxide by combusting a granulated 8 sulfur or emulsoid sulfur f 11 Sulfur dioxide is used as an intermediate in a number of different 12 applications, including sulphonation, the generation of sulfuric acid, and to 13 producx sulfur trioxide in electrostatic flue gas conditioning systems which use 14 sulfur trioxide as a flue gas conditioning agent. Flocdmstatic fhx gas c~ditioning systems are used to condition the exhaust flue gas of coal burning 16 systems, such as coal fired electric generating systems, to enhance the 17 efficiency of the electrostatic precipitator in removing particulate matter, such _ 18 as fly ash, from the flue gas. Typically) in an elatrostatic flue gas 19 conditioning system, elemental sulfur is combusted or burned to generate sulfur dioxide (SOS. The SOI is then catalyzed to convert it into sulfur 21 trioxide (SO,). The SO, is then injected into an electrostatic prxipitator to 22 condition the flue gas passing therethmugh to enhance the efficiency of the 23 electrostatic prxipitator in removing particulate matter from the flue gas.
24 Such a SO~ flue gas conditioning system is disclosed in U.S. Patent No.
24 Such a SO~ flue gas conditioning system is disclosed in U.S. Patent No.
5,032,154.
26 Heretofore, elemental sulfur has been used as a source of sulfur which 27 is combusted to generate SOr Elemental sulfur is sulfur in its molten state.
1 While it is inexpensive and does not readily burn, it has a number of 2 characteristics which make it difficult to handle and store.
3 Elemental sulfur is delivered molten at about 280'.F and must be kept 4 at or near this temperature for successful pumping and handling. The viscosity of sulfur varies greatly with temperature. Below about 260' F the 6 viscosity of sulfur increases quickly so that it can no longer be pumped by 7 conventional means. Above about 300' F, sulfur polymerizes into a 8 toothpaste-like consistency and again cannot be pumped by conventional 9 means. Elemental sulfur also has trace amounts of hydrogen sulfide which must be vented to atmosphere. Elemental sulfur also sublimates (changes 11 from a solid to a gas and back to a solid) so that all elemental sulfiu storage 12 equipment must be steam jacketed to prevent sulfur crystal accumulations.
13 For these reasons, elemental sulfur storage and handling systems must 14 be carefully designed to keep the elemental sulfur molten by keeping it within a very narrow temperature range of 270' F - 290' F. S03 flue gas 16 conditioning systems which use elemental sulfur as the feedstock typically 17 store the molten elemental sulfur in insulated steel tanks or concrete pits.
18 This storage vessel is heated, usually by steam coils installed in the bottom of 19 the storage vessel. The steam coils are typically formed in a U-shape so condensate is formed in the coils as the steam cools. Thus, the elemental 21 sulfur storage vessel must have provisions for a steam supply and for 22 condensate disposal to a drainage facility.
23 Elemental sulfur storage vessels are also exposed to attack from small 24 quantities of sulfuric acid which forms on the surface of the sulfur.
Although rare, this occasionally necessitates repairs which are costly, time consuming, 26 and carry the risk of fire.
27 When the elemental sulfur is pumped from the storage vessel to the 28 sulfur furnace, where it is combusted to form SOZ, its temperature must be 29 kept within the above described narrow range of 270' F - 290' F.
Consequently, the elemental sulfur is typically pumped through steam jacketed 31 piping with close temperature control maintained. To maintain the elemental 32 sulfur at the proper temperature throughout the steam jacketed piping, steam -- WO 94/20414 ~ ~ . . PCTIUS94/01973 1 must typically be introduced at several points and condensate must also be 2 drained from several points. Steam jacketed sulfur piping lines must also 3 allow for pipe expansion. As a result, steam jacketed sulfur piping lines are 4 expensive.
Elemental sulfur is unloaded into the storage vessel from a truck or rail 6 car by the use of steam jacketed pumps which often include steam jacketed 7 hoses. Further, although delivered "molten, " the elemental sulfur often has 8 cooled to the point where it is too viscous to be pumped properly. Steam 9 must therefore be made available to the truck or rail car for heating the elemental sulfur to proper pumping temperatures as well as for the steam 11 jacketed pumps and hoses used to unload the elemental sulfur.
12 The elemental sulfur is pumped from the storage vessel to the sulfur 13 furnace by steam jacketed reciprocating pumps or submerged gear pumps.
14 The reciprocating pumps require piping with check valves to prevent sulfur from flowing back during return strokes of the pump. These pumps also tend 16 to leak because sulfur flows from all but the tightest pump joints.
17 Hydrocarbons in the sulfur also tend to the clog the pumps and check valves.
18 The pumping systems thus require significant maintenance on a periodic basis 19 and tend to be the major maintenance item in sulfur based flue gas conditioning systems. Submerged gear pump assemblies have the gear pump 21 submerged in the elemental sulfur and eliminate much of the maintenance 22 problem. However, submerged gear pumps also require periodic 23 maintenance.
24 The temperature of the various components of the elemental sulfur feedstock system must be carefully maintained to prevent minor temperature 26 fluctuations which would quickly stop sulfur flow. As mentioned, such 27 temperature control is achieved by the use of steam heating coils, steam 28 pumps, and steam jacketed piping.
29 Although the amount of steam required by such elemental sulfur feedstock systems is relatively small, in the order of fifty to four hundred 31 pounds per hour, saturated steam is usually not available in electric power 32 generating plants. Consequently, the steam must be obtained by de-WO 94110414 . 2 1 5 8 1 3 1 1 superheating high quality steam from turbine blood systems or by the use of 2 a separate boiler. In either case, such system steam, and often the 3 condensate, is expensive and one of the major cost factors that is evaluated by 4 a potential user of a SO, flue gas conditioning system in deciding whether to install such a system.
It is therefore an objective of an aspect of this invention to eliminate the 7 disadvantages attendant with the use of an elemental sulfur feedstock systan, 8 such as are used in SOj flue gas conditioning systems) by using graaulatcd 9 sulfur or emulsoid sulfur as the fcedstock for the sulfur which is combusted to generate SO=.
13 In a method and apparatus in accordance with the invention, sulfur 14 dioxide is generated by combusting sulfur in a sulfur furnace. 'The sulfur combusted is provided in either granulated or emulsoid form to the sulfur 16 furnace.
17 In an embodiment of the invention, a SOj flue gas conditioning systaa 18 has a sulfur burner or funract for combusting sulfur supplied by a sulfur 19 feedstock system into SO~, a catalytic converter for catalyzing the SO=
into SO,, and means for injecting the SO~ into an electrostatic precipitator. The 21 sulfur feodstock system can be a granulated sulfur feedstock systan which 22 supplies granulated sulfur to the sulfur burner or as emulsoid sulfur feedstock 23 system which supplies emulsoid sulfur to the sulfur burner.
24 In accordance with the further embodiment of the invention, the method comprises:
26 A flue gas conditioning apparatus for conditioning the flue gas 27 flowing in a flue fmm a boiler to an electrostatic precipitator by injecting sulfur 2g trioxide into the flue gas upstream of the electrostatic precipitator, comprising 29 a. a source of granulated sulfur;
b. a sulfur furnace for combusting the granulated sulfur to generate 31 gnus sulfur dioxide;
wo 9anoaia pc'rn~s9orom3 2158131.
- 4a-1 c. transport means coupled to the source of granulated sulfur and 2 the sulfur furnace for transporting the granulated sulfur to the sulfur 3 furnace.;
4 d. a catalytic converter coupled to the sulfur furnace for generating sulfur trioxide from the sulfur dioxide generated by the sulfur furnace; and e. a plurality of injection probes mounted in the flue duct g upstream of the electrostatic precipitator and coupled to the catalytic g cattverta for injecting the sulfur trioude generated by the catalytic converter into the flue gas flowing through the flue duct.
11 In accordance with the further embodiment of the invention, the method 12 comprises:
13 A flue gas conditioning apparatus for conditioning the flue gas 14 ~o~g ~ a flue duct from a boiler to an electrostatic precipitator by injecting s~~ trioxide into the flue gas upstream of the electrostatic precipitator, 16 comprising:
1~ a. a source of granulated sulfur;
18 b. a sulfur furnace for combusting the granulated sulfur to 19 8enerate sulfur dioude, the sulfur furnace comprising a hollow shell 8 a cavity therein with an array of ceramic balls disposed in the 21 cavity wherein the granulated sulfur is dispersed against the ceramic 22 balls as it flows into the sulfur furnace and combusts thereon;
23 ~~ a pneumatic conveyor coupled to the granulated sulfur source 24 and to the sulfur furnace for conveying the granulated sulfur from the granulated sulfur source to the sulfur furnace;
26 d~ a catalytic converter coupled to the sulfur furnace for 2~ generating sulfur trioxide from the sulfur dioxide generated by the 28 sulfur furnace; and 29 e. a plurality of injection probes mounted in the flue duct upstream of the electrostatic precipitator and coupled to the catalytic 31 converter for injecting sulfur trioxide into the flue gas.
- - 2158131 v WO 94/20414 , PCTlU59410197 3 - 4b;-1 In accordance with the further embodiment of the invention, the method 2 comprises:
3 A flue gas conditioning apparatus for conditioning flue gas flowing 4 in a plurality of flue ducts by injecting sulfur trioxide into the flue gas, each flue duct coupling a boiler to an electrostatic precipitator, comprising:
a. a source of granulated sulfur, b. a plurality of sulfur furnaces for combusting the granulated g sulfur to generate gaseous sulfur dioxide;
g c: a day hopper for holding a supply of granulated sulfur located in proximity to each sulfur furnace, each day hopper coupled to the 11 sulfur furnace located in proximity to it for supplying granulated sulfur 12 to the sulfur furnace;
13 d. transport means for transporting granulated sulfur from the 14 granulated sulfur source to each day hopper;
e. each sulfur furnace coupled to a catalytic converter, each 16 catalytic converter generating sulfur trioxide from the sulfur dioxide 17 generated by the sulfur furnace to which it is coupled; and 18 f. each flue duct having a plurality of injection probes mounted 19 thereto upstream of the electrostatic precipitator to which that flue duct is coupled, each~ plurality of injection probes coupled to one of the 21 catalytic converters such that each catalytic converter is coupled to an 22 individual set of the pmbes.
23 Additional features and advantages of the invention will become 24 apparatt to those skilled in the art upon consideration of the following detailed description of preferred embodiments of the imrention, exemplifying the best 26 modes of carrying out the invention as presently perceived. The detailed 27 description particularly refers to the accompanying figures in which:
29 Brief Description of the Drawines Fig. 1 is a schematic Qf a prior art SO, flue gas conditioning system;
-w WO 94/20414 ~ PCT/US94101973 1 Fig. 2 is a schematic of a S03 flue gas conditioning system in 2 accordance with this invention;
3 Fig. 3 is a side cross-sectional view of a sulfur furnace for a S03 flue 4 gas conditioning system according to this invention;
Fig. 4 is a side cross-sectional view of a nozzle for the sulfur furnace 6 of Fig. 3 for use with a granulated sulfur feedstock system;
7 Fig. 5 is a side cross-sectional view of a nozzle for the sulfur furnace 8 of Fig. 3 for use with an emulsoid sulfur feedstock system;
9 Fig. 6 is a schematic of a system for generating sulfur dioxide in accordance with the invention;
11 Fig. 7 is a side, generally cross-sectional view of a sulfur furnace 12 which can be used in the system of Fig. 6; and 13 Fig. 8 is a schematic of a system for generating sulfur dioxide at 14 multiple locations in accordance with the invention.
16 Best Modes for Cam~ng Out the Invention 17 Referring to Fig. 1, a prior art S03 flue gas conditioning system 10 is 18 shown. Flue gas conditioning system 10 has a storage vessel 12, such as a pit 19 or a tank, for storing elemental sulfur. Sulfur pump or pumps 14 are coupled to storage tank 12 and pump elemental sulfur out of tank 12 to the inlet of a 21 sulfur furnace 16 through a steam jacketed pipe 18. Tank 12, pumps) 14 and 22 steam jacketed pipe 18 are heated by steam coils 20, 22, 24, respectively, 23 which are coupled to a source of steam (not shown).
24 Flue gas conditioning system 10 also has a process blower 26 having an inlet coupled to a bag house or air filter 28 and an outlet coupled to an 26 inlet of a heater 30. An outlet of heater 30 is coupled to the inlet of sulfur 27 furnace 16. An outlet of sulfur furnace 16 is coupled to ~ n inlet of catalytic 28 converter 32 and an outlet of catalytic converter is coupled to probes 34.
29 Probes 34 are mounted in an electrostatic precipitator (not shown) of an electrostatic flue gas pollution control system (not shown).
31 In operation, elemental sulfur is pumped from tank 12 by pumps) 14 32 through steam jacketed pipe 18 to the inlet of sulfur furnace 16. The 1 , temperature of tank 12, pumps) 14 and steam jacketed pipe 18 is 2 appropriately controlled by the use of steam coils 20, 22, 24 to maintain the 3 temperature of the elemental sulfur betwetn 270' F - 290.' F to keep it in its 4 proper molten state so that it can be pumped.
Process blower 26 draws air in through bag house 28, which filters the 6 air, and forces it into heater 30 and then into sulfur furnace 16. The heated 7 air c~tacts the elemental sulfur in sulfur furnace 16 which combusts the 8 elaamtal sulfur. The combustion of the elemental sulfur generates SO= which 9 is forced from the outlet of sulfur furnace 16 into the inlet of catalytic converter 32. Catalytic converter 32 catalyzes the SO= into SOj which rhea 11 flows from an output of catalytic converter 32 into probes 34 which injects the 12 SOj into the eloctzostatic precipitator (not shown) for conditioning the flue gas 13 flowing through the elatrostatic precipitator. Flue gas conditioning system 14 10 is described in more detail in United States Patent No. 5,032,154) owned by Wilhelm Environmental Technologies) Inc.) the owner of this application.
17 Refet3ing to Fig. 2, a SO3 flue gas conditioning sys~n 50 aecxtrdiag 18 to this invention is shown. Flue gas conditioning system 50 includes a source 19 of granulated sulfur 52. As used herein, "granulated sulfur~ means solid sulfur in pataiculate form such as powder or granules. The granulated sulfur 21 can be powderod sulfur) flake sulfur, prill, BB's, pellets, or the lilac.
22 Since sulfur dust can explode) granulated sulfur source 52 preferably 23 includes an inerting system to prevent explosions such as a carbon dioxide or 24 nitrogen inerting system. Illustratively) granulated sulfur source 52 is a nitrogen or carbon dioxide inerting tank in which granulated sulfur is stored 26 such as the inening tank sold by Jim Pyle) Production Design Co., Box 462) 27 544 Aspen Hall, Harrodsburg, Kentucky 40330) under the trade name 28 Transilo. However, depending on the type of granulated sulfur used, inerting 29 may not be required. For example, granulated sulfur in the form of grill, BB's) pellets and flakes forms less sulfur dust than does powdered sulfur and 31 granulated sulfur in this form may not require inerting.
WO 94/20414 PCT/US94l01973 _7_ 1 A conveyor 54, which is illustratively a precision insulated screw 2 conveyor, carries granulated sulfur from granulated sulfur source 52 to an 3 inlet of a sulfur exhauster 56. Sulfur exhauster 56 is illustratively a small 4 blower capable of handling granulated sulfur. Sulfur exhauster 56 forces the granulated sulfur into an inlet of heater/burner 58. An outlet of heater/burner 6 58 is coupled to an inlet of sulfur furnace 60 and an outlet of sulfur furnace 7 60 is coupled to an inlet of catalytic converter 62. An outlet of catalytic 8 converter 62 is coupled to probes 64 which are mounted in an electrostatic 9 precipitator (not shown) of an electrostatic flue gas pollution control system (not shown).
11 Flue gas conditioning system 50 also has a bag house or air filter 66 12 having an outlet coupled to an inlet of a process blower 68 and to an inlet of 13 sulfur exhauster 56. An outlet of process blower 68 is coupled to an inlet of 14 heater/burner 58.
Flue gas conditioning system 50 operates in much the same way as the 16 flue gas conditioning system 10 shown in Fig. 1 except granulated sulfur is 17 used as the sulfur feedstock instead of elemental sulfur. Conveyor 54 carries 18 the granulated sulfur from granulated sulfur source 52 to the inlet of sulfur 19 exhauster 56. Sulfur exhauster 56 forces the granulated sulfur into heater/burner 58 where it is mixed with air blown into heater/burner 58 by 21 process blower 68. Process blower 68 draws air in from the outside through 22 bag house or air filter 66.
23 The granulated sulfur is blown into heater/burner 58 by the air flow 24 from process blower 68 and then into sulfur furnace 60 where it combusts into SO2. The SOZ then flows from sulfur furnace 60 into catalytic converter 62 26 which catalyzes the SOZ into S03. The S03 flows into probes 64 which inject 27 it into the electrostatic precipitator (not shown) for conditioning the flue gas 28 flowing through the electrostatic precipitator.
29 An emulsoid sulfur feedstock system, which can be used as an alternative to the granulated sulfur feedstock system, is shown by dashed lines 31 in Fig. 2. The emulsoid sulfur feedstock system includes a source 70 of 32 emulsoid sulfur, which can be a tank, having a sulfur pump 72 coupled to an _g_ 1 outlet thereof. An outlet of sulfur pump 72 is coupled to an inlet of an 2 atomizing spray nozzle 200 (Fig. 5) of sulfur furnace 60. A source 74 of 3 atomizing air is also coupled to an ~~inlet of atomizing spray nozzle 200 (Fig.
4 5).
In operation, emulsoid sulfur is pumped by sulfur pump 72 from 6 emulsoid sulfur source 70 to the inlet of atomizing spray nozzle 200 of sulfur 7 furnace 60 where it is mixed with atomizing air and sprayed out into sulfur 8 furnace 60 where it mixes with hot combustion air. Process blower 68 draws 9 air in through bag house 66 and forces it through heater/burner 58, which heats it, into sulfur furnace 60. The emulsoid sulfur combusts into SOZ in 11 sulfur furnace 60 which is then catalyzed into S03 by catalytic converter 12 for injection into the electrostatic precipitator (not shown) by probes 64.
13 Referring to Fig. 3, a sulfur furnace 80 is shown which can preferably 14 be used in the S03 flue gas conditioning system 50 of Fig. 2. Sulfiu furnace 80 includes a nozzle 82 where sulfur is mixed with combustion air and begins 16 the combustion process. Illustratively, nozzle 82 is either a nozzle for a 17 granulated sulfur feedstock, such as nozzle 100 (Fig. 4), or a nozzle for 18 emulsoid sulfur feedstock, such as atomizing nozzle 200 (Fig. S).
19 Furnace 80 comprises an outer shell or casing 84 and an inner shell or casing 86 having a refractory lining 88 disposed therebetween. Illustratively, 21 outer casing 84 is made of a schedule 40 mild steel and inner casing 86 is 22 made from a 20 gauge mild steel. The refractory lining is illustratively a 23 castable lining which is pumped into place between inner casing 86 and outer 24 casing 84, vibrated into place and heat treated to produce a long wearing monolithic refractory surface. Outer casing 84 is illustratively insulated for 26 personnel protection.
27 Referring to Fig. 4, nozzle 100 for granulated sulfur feedstock is 28 shown. Nozzle 100 has a first or inlet ring section 102 and a second or outlet 29 ring section 104 having a larger diameter than inlet ring section 102, and a sloped shoulder section 106 therebetween. Inlet ring section 102 and sloped 31 shoulder section 106 have a cylindrical combustion air passageway 108 32 extending axially through their center and which expands outwardly in outlet z~~s~~~
1 ring section 104 to a generally conical throat 110 which opens to the interior 2 of sulfur furnace 80. Cylindrical combustion air passageway has an inlet 109 3 which is coupled to the outlet of process blower 68 (Fig. 2). Nozzle 100 has 4 a granulated sulfur inlet 112 which is coupled to the outlet of sulfur exhauster 56 (Fig. 2) by pipe 114. Inlet 112 opens to a passageway 116 formed in inlet 6 ring section 102. Passageway 116 communicates with swirl or cyclone 7 passageways 118 formed in outlet ring section 104 surrounding throat 110.
8 Passageways 118 open to the interior of sulfur furnace 80 at 122. An oil or 9 gas burner 120 is mounted at generally the center of throat 110 in outlet ring section 104 at the interface between nozzle 100 and sulfur furnace 80. In this 11 embodiment, sulfur furnace 80 with nozzle 100 combines the functions of 12 heater/burner 58 and sulfur furnace 60 of Fig. 2.
13 In operation, combustion air is blown into inlet 109 of cylindrical 14 passageway 108 by process blower 68 (Fig. 2) and forced through passageway 108 into generally conical throat section 110 where it is heated by burner 120 16 and flows out into the interior of sulfur furnace 80. Granulated sulfur is 17 blown into passageway 116 in inlet ring section 102 through inlet 112 by 18 sulfur exhauster 56 (Fig. 2). The granulated sulfur is forced through 19 passageway 116 into swirl or cyclone passageways 118 in outlet ring section 104 which impart a swirl or cyclone effect to the granulated sulfur so that it 21 is swirling as it flows out of passageways 118 into the interior of sulfur 22 furnace 80. When the granulated sulfur flows into furnace 80, it contacts the 23 hot combustion air that has been heated by burner 120 and combusts at 24 generally the interface between nozzle 100 and furnace 80 into S02.
Referring to Fig. 5, atomizing nozzle 200 for use with emulsoid sulfur 26 feedstock is shown. Atomizing nozzle 200 has an outer hollow cylindrical 27 case 202, an inner cylindrical spray head 204, and a web section 206 28 extending between outer case 202 and cylindrical spray head 204 to hold 29 cylindrical spray head 204 in place in outer cylindrical case 204. Web section 206 includes passageways (not shown) which extend therethrough to allow 31 combustion air to flow through outer cylindrical case 202 around spray head 215 813 ~.
- to -1 204 into the interior of sulfur furnace 80. Outer, hollow cylindrical case 2 has an inlet 203 which is coupled to the outlet of heater/burner 58 (Fig.
2).
3 Cylindrical spray head 204 has an inlet end 208 and an outlet end 210.
4 An emulsoid sulfur passageway 212 extends from an emulsoid inlet 214 in inlet end 208 through cylindrical 'spray head 204 to outlet end 210. Emulsoid 6 inlet 214 is coupled by a pipe 2'16 to sulfur pump 72 (Fig. 2). An atomizing 7 air passageway 218 extends from an atomizing air inlet 220 in inlet end 208 8 through cylindrical spray head 204 to outlet end 210. Atomizing air inlet 9 is coupled to the source of atomizing air 74 (Fig. 2). Atomizing air passageway 218 and emulsoid sulfur passageway 212 join at the outlet end 210 11 of cylindrical spray head 204 and open into the interior of sulfur furnace 80.
12 In operation, emulsoid sulfur is pumped from emulsoid sulfur source 13 70 by sulfur pump 72 into emulsoid sulfur passageway 212 in spray head 204 14 of nozzle 200 through emulsoid sulfur inlet 214. Atomizing air is blown by atomizing air source 74 (Fig. 2) into atomizing air passageway 218 in spray 16 head 204 through atomizing air inlet 220. Hot combustion air, which has 17 been heated by heater/burner 58, flows into inlet 203 in outer casing 202 of 18 nozzle 200. The hot combustion air flows through outer casing 202 around 19 spray head 204 and out into sulfur furnace 80. The atomizing air and emulsoid sulfur mix at the outlet end 210 of spray head 204 and the atomizing 21 air/emulsoid sulfur mixture is sprayed by spray head 204 out into sulfur 22 furnace 80 where it contacts the hot combustion air which causes the sulfur 23 particles in the emulsoid sulfur to combust as well as evaporating the water 24 in the emulsoid sulfur. The sulfur particles combust into S4z which then flows from sulfur furnace 80 into catalytic converter 62 (Fig. 2) which 26 catalyzes the SOz into S03. The S03 is then injected into the electrostatic 27 precipitator (not shown) of the electrostatic flue gas pollution control system 28 (not shown) by probes 64 (Fig. 2).
29 Referring to Fig. 6, a system 300 for generating sulfur dioxide in accordance with the invention is shown. Sulfur dioxide generating system 300 31 includes a source of granulated sulfur, such as hopper 302 in which granulated 32 sulfur is held. Hopper 302 can illustratively be a Transilo inerting tank sold WO 94/20414 21 ~ 813 .~ ~T~S94/01973 1 by Jim Pyle, Production Design Co. , Box 462, 544 Aspen Hall, Harrodsburg, 2 Kentucky 40330. However, if inerting of the granulated sulfur is not 3 requireri, hopper 302 can be a hopper or silo of conventional design for 4 holding granulated material.
Hopper 302 has an outlet 304 coupled to an inlet 306 of a pneumatic 6 feed unit 308. Pneumatic feed unit 308 is illustratively a RotoFeedm 7 pneumatic conveying unit manufactured by Simon Air Systems, P. O. Box 8 326, Milford, Ohio 45150. Pneumatic feed unit 308 has a pneumatic feeder 9 310 having a conveying air inlet 312 coupled to a source of compressed air (not shown) by air line 316. Pneumatic feeder 310 of pneumatic feed unit 308 11 has a material outlet 314 coupled by pipe 318 'to an inlet 320 of a sulfur 12 furnace 322.
13 In operation, granulated sulfur is stored in hopper 302. Illustratively, 14 pneumatic feed unit 308 is mounted to the bottom of hopper 302 with its inlet 306 coupled to the outlet 304 of hopper 302 so that granulated sulfur is fed 16 into pneumatic feed unit 308 by gravity or by gravity assist. Pneumatic feeder 17 310 of pneumatic feed unit 308 pneumatically feeds the granulated sulfur to 18 sulfur furnace 322. Illustratively, pneumatic feeder 310 blows the granulated 19 sulfur through pipe 318 at a rate of about 4 CFM which is sufficiently fast to eliminate any explosion hazard which might be caused by sulfur dust.
21 Sulfur furnace 322 combusts the granulated sulfur fed to it by 22 pneumatic feed unit 308 which generates sulfur dioxide. The sulfur dioxide 23 flows out of sulfur furnace 322 through an outlet 324 of sulfur furnace 322.
24 Depending on the type of granulated sulfur used, hopper 302 and pneumatic feed unit 308 may require inerting. If inerting is required, then a 26 Transilo tank discussed above can be used as hopper 302. Pneumatic feed 27 unit 308 then preferrably has an inert gas inlet 326 coupled by a pipe 330 to 28 a source of inert gas, such as a tank of nitrogen 332.
29 Sulfur furnace 322 can be any sulfur furnace which can combust granulated sulfur. For example, sulfur furnace 322 can be sulfur furnace 80 31 shown in Fig. 3 or sulfur furnace 400 shown in Fig. 7.
1 A modification to system 300 is shown in phantom in Fig. 6 in which 2 the granulated sulfur is pulverized into finely divided sulfur, e. g. , 300 mesh, 3 immediately before the sulfur is introduced into furnace 322. In this modified 4 embodiment, a pulverizer 326 is coupled between pipe 318 and inlet 320 of sulfur furnace 322. Illustratively, pulverizer 326 is mounted to the inlet 320 6 of sulfur furnace 322. ' " Granulated sulfur supplied through pipe 318 is 7 introduced into pulverizer 326 which pulverizes it into finely divided sulfur 8 (300 mesh). The pulverized sulfur is then introduced into sulfur furnace 322 9 where it combusts. Pulverizer 326 can illustratively be commercially available ball or ring pulverizes of small capacity, e. g. , 10 - 200 pounds/hour. Such 11 a pulverizer can be an Atritor Cell Mill model 250 manufactured by Allis 12 Mineral Systems Division of Kennedy Van Saun, 350 Railroad Street, 13 Danville Pennsylvania, U.S.A. 17821-2046. By pulverizing the granulated 14 sulfur before it is introduced into furnace 322, granulated sulfur in any commercial form, such as flake, prill, pellet or BB's can be stored and 16 conveyed to the pulverizer 326. The pulverized sulfur flows, illustrativley by 17 pneumatic conveyance, from the pulverizer 326 into furnace 322 at a rate 18 sufficient so as to eliminate the risk of explosion due to sulfur dust. A
day 19 hopper, such as described below with reference to Fig. 8, may be provided in proximity to the pulverizer wherein the granulated sulfur is fed to the day 21 hopper and the day hopper provides the granulated sulfur to pulverizer 326 for 22 pulverizing. Pulverizing the granulated sulfur before introduction into the 23 sulfur furnace is advantageous in that the finely divided sulfur produces the 24 most vigorous flame and requires the smallest furnace envelope, resulting in improved process economies.
26 Fig. 7 shows a sulfur furnace 400 which can be used for sulfur furnace 27 122 of Fig. 6, or for sulfur furnace 60 of Fig. 2. Sulfur furnace 400 is 28 illustratively a spherical array checker work sulfur furnace and comprises an 29 outer shell or casing 402 and an inner casing or shell 404 having a refractory lining 406, such as ceramic, therebetween. Illustratively, outer shell 402 is 31 made of a schedule 40 mild steel and inner shell 404 is made from a 20 gauge 32 mild steel. Refractory lining 406 can illustratively be a castable lining such WO 94120414 g I ~ ~ PCT/US94I019'73 1 as described above with regard to lining 86 of furnace 80 (Fig. 3). Outer 2 casing 402 is illustratively insulated for personnel protection.
3 Furnace 400 further has an inlet 408 and an outlet 410. Inlet 408 4 illustratively has a six inch pipe "T" 409 affixed thereto having a sulfur inlet end 412 and a hot gas inlet end 414. Hot gas inlet end 414 is coupled to a 6 source of hot gas, such as heater 58 (Fig. 2). Hot gas inlet end 414 7 illustratively has baffles 415 affixed therein for imparting a swirl or cyclonic 8 effect to the hot gas flowing thereinto. Pipe 318 (Fig. 6), which is coupled 9 to the material outlet 314 of pneumatic feed unit 308, extends into pipe "T"
409 through sulfur inlet end 412 to the inlet 408 of sulfur furnace 400.
11 Furnace 400 further incudes a checker work array 418 of ceramic balls 12 420 disposed therein. Illustratively, a stainless steel grate 422 extends 13 transversely across the interior of furnace 400 and holds the checker work 14 array 418 of ceramic balls 420. Ceramic balls 420 are illustratively two inch ceramic balls. Although furnace 400 is shown horizontally in Fig. 7, it is 16 preferrably mounted vertically in actual use.
17 In operation, granulated sulfur is supplied by pipe 318 to the inlet 408 18 of furnace 400 where it is blown into the interior of furnace 400 against 19 ceramic balls 420. Hot gas is introduced to the interior of furnace 400 through hot gas inlet 414 of pipe "T" 409. Baffles 415 impart a swirl or 21 cyclonic effect to the hot gas which aids in dispersing the granulated sulfur 22 against ceramic balls 420 in the interior of furnace 400. The hot gas raises 23 the temperature of the ceramic balls 420 to a sufficient level to combust the 24 granulated sulfur. The granulated sulfur combusts after being blown onto the surfaces of ceramic balls 420 and generates sulfur dioxide. After furnace 400 26 has been combusting the granulated sulfur for a sufficient period of time, the 27 heat generated by the combustion of the granulated sulfur is sufficient to 28 maintain combustion so that hot gas no longer need be introduced through hot 29 gas inlet 414 of pipe "T" 409. The gaseous sulfur dioxide exits through outlet 410 of furnace 400 and through pipe 424 which is coupled to outlet 410. Pipe 31 424 is illustratively an eight inch pipe.
1 Fig. 8 is a schematic of a system 500 for generating sulfur dioxide at 2 multiple locations according to the invention. System 500 is a modification 3 of system 300 of Fig. 3 and like elements are identified with like reference 4 numbers. System 500 includes hopper 302 having its outlet 304 coupled to an inlet of a conveyor 502. Conveyor 502 is illustratively a dense phase 6 conveyor such as a Model DPG-1B Cyclonaire Bottom Discharge Dense Phase 7 Conveyor, manufactured by Cyclonaire, Box 366, York, Nebraska 68467, or 8 a Densairveyor manufactured by Simon Air Systems. An outlet of conveyor 9 502 is coupled to inlets 306 of pneumatic feed units 308. A storage hopper or day hopper is provided in proximity with each sulfur furnace 322 for 11 holding a quantity of granulated sulfur such as might be used in one day.
12 Illustratively, the storage hopper or day hopper is part of pneumatic feed unit 13 308 such as indicated by reference number 309. The material outlet 314 of 14 each pneumatic feed unit 308 is coupled to a respective inlet 320 of a respective sulfur furnace 322. Sulfur furnaces 322 with their associated 16 pneumatic feed units 308 can be located at different locations. Further, more 17 than two sulfur furnaces 322 with associated pneumatic feed units 308 can be 18 used in system 500, with the size of hopper 302 and conveyor 502 modified 19 accordingly to accommodate the number of sulfur furnaces 322 and associated pneumatic feed units 308 included in system 500.
21 The use of solid granulated sulfur feedstock or emulsoid sulfur 22 feedstock provides significant advantages over the use of elemental sulfur 23 feedstock which has been heretofore been used to generate sulfur dioxide, 24 such as in S03 flue gas conditioning systems. Emulsoid sulfur is a suspension of water and very fine sulfur particles on the order of four to six microns.
26 The emulsion contains around seventy percent sulfur and thirty percent water 27 which permits the emulsoid sulfur to be handled as a liquid. Moreover, the 28 need for special steam heating of the type required with elemental sulfur is 29 eliminated. All that is required is a simple heating system to keep the emulsoid sulfur from freezing such as heat tape disposed around emulsoid 31 sulfur source 70 (Fig. 2). Further, because emulsoid sulfur is about thirty 32 percent water, there is no risk of explosion. Similarly, the granulated sulfur _._ WO 94/20414 215 8131 ~T~S94101973 1 feedstock, being a solid, eliminates the need for the special steam heating 2 needed for elemental sulfur.
3 The granulated sulfur feedstock system and emulsoid sulfur feedstock 4 system described herein can be advantageously used in any system which requires the generation of sulfur dioxide, such as in new sulfur trioxide flue 6 gas conditioning systems and in the retrofit of existing sulfur trioxide flue gas 7 conditioning systems by replacing the elemental sulfur feedstock system with 8 the granulated sulfur feedstock system or emulsoid sulfur feedstock system of 9 this invention.
Although the invention has been described in detail with reference to 11 certain preferred embodiments, materials and specific examples, variations and 12 modifications exist within the scope and spirit of the invention as described 13 and as defined in the following claims.
26 Heretofore, elemental sulfur has been used as a source of sulfur which 27 is combusted to generate SOr Elemental sulfur is sulfur in its molten state.
1 While it is inexpensive and does not readily burn, it has a number of 2 characteristics which make it difficult to handle and store.
3 Elemental sulfur is delivered molten at about 280'.F and must be kept 4 at or near this temperature for successful pumping and handling. The viscosity of sulfur varies greatly with temperature. Below about 260' F the 6 viscosity of sulfur increases quickly so that it can no longer be pumped by 7 conventional means. Above about 300' F, sulfur polymerizes into a 8 toothpaste-like consistency and again cannot be pumped by conventional 9 means. Elemental sulfur also has trace amounts of hydrogen sulfide which must be vented to atmosphere. Elemental sulfur also sublimates (changes 11 from a solid to a gas and back to a solid) so that all elemental sulfiu storage 12 equipment must be steam jacketed to prevent sulfur crystal accumulations.
13 For these reasons, elemental sulfur storage and handling systems must 14 be carefully designed to keep the elemental sulfur molten by keeping it within a very narrow temperature range of 270' F - 290' F. S03 flue gas 16 conditioning systems which use elemental sulfur as the feedstock typically 17 store the molten elemental sulfur in insulated steel tanks or concrete pits.
18 This storage vessel is heated, usually by steam coils installed in the bottom of 19 the storage vessel. The steam coils are typically formed in a U-shape so condensate is formed in the coils as the steam cools. Thus, the elemental 21 sulfur storage vessel must have provisions for a steam supply and for 22 condensate disposal to a drainage facility.
23 Elemental sulfur storage vessels are also exposed to attack from small 24 quantities of sulfuric acid which forms on the surface of the sulfur.
Although rare, this occasionally necessitates repairs which are costly, time consuming, 26 and carry the risk of fire.
27 When the elemental sulfur is pumped from the storage vessel to the 28 sulfur furnace, where it is combusted to form SOZ, its temperature must be 29 kept within the above described narrow range of 270' F - 290' F.
Consequently, the elemental sulfur is typically pumped through steam jacketed 31 piping with close temperature control maintained. To maintain the elemental 32 sulfur at the proper temperature throughout the steam jacketed piping, steam -- WO 94/20414 ~ ~ . . PCTIUS94/01973 1 must typically be introduced at several points and condensate must also be 2 drained from several points. Steam jacketed sulfur piping lines must also 3 allow for pipe expansion. As a result, steam jacketed sulfur piping lines are 4 expensive.
Elemental sulfur is unloaded into the storage vessel from a truck or rail 6 car by the use of steam jacketed pumps which often include steam jacketed 7 hoses. Further, although delivered "molten, " the elemental sulfur often has 8 cooled to the point where it is too viscous to be pumped properly. Steam 9 must therefore be made available to the truck or rail car for heating the elemental sulfur to proper pumping temperatures as well as for the steam 11 jacketed pumps and hoses used to unload the elemental sulfur.
12 The elemental sulfur is pumped from the storage vessel to the sulfur 13 furnace by steam jacketed reciprocating pumps or submerged gear pumps.
14 The reciprocating pumps require piping with check valves to prevent sulfur from flowing back during return strokes of the pump. These pumps also tend 16 to leak because sulfur flows from all but the tightest pump joints.
17 Hydrocarbons in the sulfur also tend to the clog the pumps and check valves.
18 The pumping systems thus require significant maintenance on a periodic basis 19 and tend to be the major maintenance item in sulfur based flue gas conditioning systems. Submerged gear pump assemblies have the gear pump 21 submerged in the elemental sulfur and eliminate much of the maintenance 22 problem. However, submerged gear pumps also require periodic 23 maintenance.
24 The temperature of the various components of the elemental sulfur feedstock system must be carefully maintained to prevent minor temperature 26 fluctuations which would quickly stop sulfur flow. As mentioned, such 27 temperature control is achieved by the use of steam heating coils, steam 28 pumps, and steam jacketed piping.
29 Although the amount of steam required by such elemental sulfur feedstock systems is relatively small, in the order of fifty to four hundred 31 pounds per hour, saturated steam is usually not available in electric power 32 generating plants. Consequently, the steam must be obtained by de-WO 94110414 . 2 1 5 8 1 3 1 1 superheating high quality steam from turbine blood systems or by the use of 2 a separate boiler. In either case, such system steam, and often the 3 condensate, is expensive and one of the major cost factors that is evaluated by 4 a potential user of a SO, flue gas conditioning system in deciding whether to install such a system.
It is therefore an objective of an aspect of this invention to eliminate the 7 disadvantages attendant with the use of an elemental sulfur feedstock systan, 8 such as are used in SOj flue gas conditioning systems) by using graaulatcd 9 sulfur or emulsoid sulfur as the fcedstock for the sulfur which is combusted to generate SO=.
13 In a method and apparatus in accordance with the invention, sulfur 14 dioxide is generated by combusting sulfur in a sulfur furnace. 'The sulfur combusted is provided in either granulated or emulsoid form to the sulfur 16 furnace.
17 In an embodiment of the invention, a SOj flue gas conditioning systaa 18 has a sulfur burner or funract for combusting sulfur supplied by a sulfur 19 feedstock system into SO~, a catalytic converter for catalyzing the SO=
into SO,, and means for injecting the SO~ into an electrostatic precipitator. The 21 sulfur feodstock system can be a granulated sulfur feedstock systan which 22 supplies granulated sulfur to the sulfur burner or as emulsoid sulfur feedstock 23 system which supplies emulsoid sulfur to the sulfur burner.
24 In accordance with the further embodiment of the invention, the method comprises:
26 A flue gas conditioning apparatus for conditioning the flue gas 27 flowing in a flue fmm a boiler to an electrostatic precipitator by injecting sulfur 2g trioxide into the flue gas upstream of the electrostatic precipitator, comprising 29 a. a source of granulated sulfur;
b. a sulfur furnace for combusting the granulated sulfur to generate 31 gnus sulfur dioxide;
wo 9anoaia pc'rn~s9orom3 2158131.
- 4a-1 c. transport means coupled to the source of granulated sulfur and 2 the sulfur furnace for transporting the granulated sulfur to the sulfur 3 furnace.;
4 d. a catalytic converter coupled to the sulfur furnace for generating sulfur trioxide from the sulfur dioxide generated by the sulfur furnace; and e. a plurality of injection probes mounted in the flue duct g upstream of the electrostatic precipitator and coupled to the catalytic g cattverta for injecting the sulfur trioude generated by the catalytic converter into the flue gas flowing through the flue duct.
11 In accordance with the further embodiment of the invention, the method 12 comprises:
13 A flue gas conditioning apparatus for conditioning the flue gas 14 ~o~g ~ a flue duct from a boiler to an electrostatic precipitator by injecting s~~ trioxide into the flue gas upstream of the electrostatic precipitator, 16 comprising:
1~ a. a source of granulated sulfur;
18 b. a sulfur furnace for combusting the granulated sulfur to 19 8enerate sulfur dioude, the sulfur furnace comprising a hollow shell 8 a cavity therein with an array of ceramic balls disposed in the 21 cavity wherein the granulated sulfur is dispersed against the ceramic 22 balls as it flows into the sulfur furnace and combusts thereon;
23 ~~ a pneumatic conveyor coupled to the granulated sulfur source 24 and to the sulfur furnace for conveying the granulated sulfur from the granulated sulfur source to the sulfur furnace;
26 d~ a catalytic converter coupled to the sulfur furnace for 2~ generating sulfur trioxide from the sulfur dioxide generated by the 28 sulfur furnace; and 29 e. a plurality of injection probes mounted in the flue duct upstream of the electrostatic precipitator and coupled to the catalytic 31 converter for injecting sulfur trioxide into the flue gas.
- - 2158131 v WO 94/20414 , PCTlU59410197 3 - 4b;-1 In accordance with the further embodiment of the invention, the method 2 comprises:
3 A flue gas conditioning apparatus for conditioning flue gas flowing 4 in a plurality of flue ducts by injecting sulfur trioxide into the flue gas, each flue duct coupling a boiler to an electrostatic precipitator, comprising:
a. a source of granulated sulfur, b. a plurality of sulfur furnaces for combusting the granulated g sulfur to generate gaseous sulfur dioxide;
g c: a day hopper for holding a supply of granulated sulfur located in proximity to each sulfur furnace, each day hopper coupled to the 11 sulfur furnace located in proximity to it for supplying granulated sulfur 12 to the sulfur furnace;
13 d. transport means for transporting granulated sulfur from the 14 granulated sulfur source to each day hopper;
e. each sulfur furnace coupled to a catalytic converter, each 16 catalytic converter generating sulfur trioxide from the sulfur dioxide 17 generated by the sulfur furnace to which it is coupled; and 18 f. each flue duct having a plurality of injection probes mounted 19 thereto upstream of the electrostatic precipitator to which that flue duct is coupled, each~ plurality of injection probes coupled to one of the 21 catalytic converters such that each catalytic converter is coupled to an 22 individual set of the pmbes.
23 Additional features and advantages of the invention will become 24 apparatt to those skilled in the art upon consideration of the following detailed description of preferred embodiments of the imrention, exemplifying the best 26 modes of carrying out the invention as presently perceived. The detailed 27 description particularly refers to the accompanying figures in which:
29 Brief Description of the Drawines Fig. 1 is a schematic Qf a prior art SO, flue gas conditioning system;
-w WO 94/20414 ~ PCT/US94101973 1 Fig. 2 is a schematic of a S03 flue gas conditioning system in 2 accordance with this invention;
3 Fig. 3 is a side cross-sectional view of a sulfur furnace for a S03 flue 4 gas conditioning system according to this invention;
Fig. 4 is a side cross-sectional view of a nozzle for the sulfur furnace 6 of Fig. 3 for use with a granulated sulfur feedstock system;
7 Fig. 5 is a side cross-sectional view of a nozzle for the sulfur furnace 8 of Fig. 3 for use with an emulsoid sulfur feedstock system;
9 Fig. 6 is a schematic of a system for generating sulfur dioxide in accordance with the invention;
11 Fig. 7 is a side, generally cross-sectional view of a sulfur furnace 12 which can be used in the system of Fig. 6; and 13 Fig. 8 is a schematic of a system for generating sulfur dioxide at 14 multiple locations in accordance with the invention.
16 Best Modes for Cam~ng Out the Invention 17 Referring to Fig. 1, a prior art S03 flue gas conditioning system 10 is 18 shown. Flue gas conditioning system 10 has a storage vessel 12, such as a pit 19 or a tank, for storing elemental sulfur. Sulfur pump or pumps 14 are coupled to storage tank 12 and pump elemental sulfur out of tank 12 to the inlet of a 21 sulfur furnace 16 through a steam jacketed pipe 18. Tank 12, pumps) 14 and 22 steam jacketed pipe 18 are heated by steam coils 20, 22, 24, respectively, 23 which are coupled to a source of steam (not shown).
24 Flue gas conditioning system 10 also has a process blower 26 having an inlet coupled to a bag house or air filter 28 and an outlet coupled to an 26 inlet of a heater 30. An outlet of heater 30 is coupled to the inlet of sulfur 27 furnace 16. An outlet of sulfur furnace 16 is coupled to ~ n inlet of catalytic 28 converter 32 and an outlet of catalytic converter is coupled to probes 34.
29 Probes 34 are mounted in an electrostatic precipitator (not shown) of an electrostatic flue gas pollution control system (not shown).
31 In operation, elemental sulfur is pumped from tank 12 by pumps) 14 32 through steam jacketed pipe 18 to the inlet of sulfur furnace 16. The 1 , temperature of tank 12, pumps) 14 and steam jacketed pipe 18 is 2 appropriately controlled by the use of steam coils 20, 22, 24 to maintain the 3 temperature of the elemental sulfur betwetn 270' F - 290.' F to keep it in its 4 proper molten state so that it can be pumped.
Process blower 26 draws air in through bag house 28, which filters the 6 air, and forces it into heater 30 and then into sulfur furnace 16. The heated 7 air c~tacts the elemental sulfur in sulfur furnace 16 which combusts the 8 elaamtal sulfur. The combustion of the elemental sulfur generates SO= which 9 is forced from the outlet of sulfur furnace 16 into the inlet of catalytic converter 32. Catalytic converter 32 catalyzes the SO= into SOj which rhea 11 flows from an output of catalytic converter 32 into probes 34 which injects the 12 SOj into the eloctzostatic precipitator (not shown) for conditioning the flue gas 13 flowing through the elatrostatic precipitator. Flue gas conditioning system 14 10 is described in more detail in United States Patent No. 5,032,154) owned by Wilhelm Environmental Technologies) Inc.) the owner of this application.
17 Refet3ing to Fig. 2, a SO3 flue gas conditioning sys~n 50 aecxtrdiag 18 to this invention is shown. Flue gas conditioning system 50 includes a source 19 of granulated sulfur 52. As used herein, "granulated sulfur~ means solid sulfur in pataiculate form such as powder or granules. The granulated sulfur 21 can be powderod sulfur) flake sulfur, prill, BB's, pellets, or the lilac.
22 Since sulfur dust can explode) granulated sulfur source 52 preferably 23 includes an inerting system to prevent explosions such as a carbon dioxide or 24 nitrogen inerting system. Illustratively) granulated sulfur source 52 is a nitrogen or carbon dioxide inerting tank in which granulated sulfur is stored 26 such as the inening tank sold by Jim Pyle) Production Design Co., Box 462) 27 544 Aspen Hall, Harrodsburg, Kentucky 40330) under the trade name 28 Transilo. However, depending on the type of granulated sulfur used, inerting 29 may not be required. For example, granulated sulfur in the form of grill, BB's) pellets and flakes forms less sulfur dust than does powdered sulfur and 31 granulated sulfur in this form may not require inerting.
WO 94/20414 PCT/US94l01973 _7_ 1 A conveyor 54, which is illustratively a precision insulated screw 2 conveyor, carries granulated sulfur from granulated sulfur source 52 to an 3 inlet of a sulfur exhauster 56. Sulfur exhauster 56 is illustratively a small 4 blower capable of handling granulated sulfur. Sulfur exhauster 56 forces the granulated sulfur into an inlet of heater/burner 58. An outlet of heater/burner 6 58 is coupled to an inlet of sulfur furnace 60 and an outlet of sulfur furnace 7 60 is coupled to an inlet of catalytic converter 62. An outlet of catalytic 8 converter 62 is coupled to probes 64 which are mounted in an electrostatic 9 precipitator (not shown) of an electrostatic flue gas pollution control system (not shown).
11 Flue gas conditioning system 50 also has a bag house or air filter 66 12 having an outlet coupled to an inlet of a process blower 68 and to an inlet of 13 sulfur exhauster 56. An outlet of process blower 68 is coupled to an inlet of 14 heater/burner 58.
Flue gas conditioning system 50 operates in much the same way as the 16 flue gas conditioning system 10 shown in Fig. 1 except granulated sulfur is 17 used as the sulfur feedstock instead of elemental sulfur. Conveyor 54 carries 18 the granulated sulfur from granulated sulfur source 52 to the inlet of sulfur 19 exhauster 56. Sulfur exhauster 56 forces the granulated sulfur into heater/burner 58 where it is mixed with air blown into heater/burner 58 by 21 process blower 68. Process blower 68 draws air in from the outside through 22 bag house or air filter 66.
23 The granulated sulfur is blown into heater/burner 58 by the air flow 24 from process blower 68 and then into sulfur furnace 60 where it combusts into SO2. The SOZ then flows from sulfur furnace 60 into catalytic converter 62 26 which catalyzes the SOZ into S03. The S03 flows into probes 64 which inject 27 it into the electrostatic precipitator (not shown) for conditioning the flue gas 28 flowing through the electrostatic precipitator.
29 An emulsoid sulfur feedstock system, which can be used as an alternative to the granulated sulfur feedstock system, is shown by dashed lines 31 in Fig. 2. The emulsoid sulfur feedstock system includes a source 70 of 32 emulsoid sulfur, which can be a tank, having a sulfur pump 72 coupled to an _g_ 1 outlet thereof. An outlet of sulfur pump 72 is coupled to an inlet of an 2 atomizing spray nozzle 200 (Fig. 5) of sulfur furnace 60. A source 74 of 3 atomizing air is also coupled to an ~~inlet of atomizing spray nozzle 200 (Fig.
4 5).
In operation, emulsoid sulfur is pumped by sulfur pump 72 from 6 emulsoid sulfur source 70 to the inlet of atomizing spray nozzle 200 of sulfur 7 furnace 60 where it is mixed with atomizing air and sprayed out into sulfur 8 furnace 60 where it mixes with hot combustion air. Process blower 68 draws 9 air in through bag house 66 and forces it through heater/burner 58, which heats it, into sulfur furnace 60. The emulsoid sulfur combusts into SOZ in 11 sulfur furnace 60 which is then catalyzed into S03 by catalytic converter 12 for injection into the electrostatic precipitator (not shown) by probes 64.
13 Referring to Fig. 3, a sulfur furnace 80 is shown which can preferably 14 be used in the S03 flue gas conditioning system 50 of Fig. 2. Sulfiu furnace 80 includes a nozzle 82 where sulfur is mixed with combustion air and begins 16 the combustion process. Illustratively, nozzle 82 is either a nozzle for a 17 granulated sulfur feedstock, such as nozzle 100 (Fig. 4), or a nozzle for 18 emulsoid sulfur feedstock, such as atomizing nozzle 200 (Fig. S).
19 Furnace 80 comprises an outer shell or casing 84 and an inner shell or casing 86 having a refractory lining 88 disposed therebetween. Illustratively, 21 outer casing 84 is made of a schedule 40 mild steel and inner casing 86 is 22 made from a 20 gauge mild steel. The refractory lining is illustratively a 23 castable lining which is pumped into place between inner casing 86 and outer 24 casing 84, vibrated into place and heat treated to produce a long wearing monolithic refractory surface. Outer casing 84 is illustratively insulated for 26 personnel protection.
27 Referring to Fig. 4, nozzle 100 for granulated sulfur feedstock is 28 shown. Nozzle 100 has a first or inlet ring section 102 and a second or outlet 29 ring section 104 having a larger diameter than inlet ring section 102, and a sloped shoulder section 106 therebetween. Inlet ring section 102 and sloped 31 shoulder section 106 have a cylindrical combustion air passageway 108 32 extending axially through their center and which expands outwardly in outlet z~~s~~~
1 ring section 104 to a generally conical throat 110 which opens to the interior 2 of sulfur furnace 80. Cylindrical combustion air passageway has an inlet 109 3 which is coupled to the outlet of process blower 68 (Fig. 2). Nozzle 100 has 4 a granulated sulfur inlet 112 which is coupled to the outlet of sulfur exhauster 56 (Fig. 2) by pipe 114. Inlet 112 opens to a passageway 116 formed in inlet 6 ring section 102. Passageway 116 communicates with swirl or cyclone 7 passageways 118 formed in outlet ring section 104 surrounding throat 110.
8 Passageways 118 open to the interior of sulfur furnace 80 at 122. An oil or 9 gas burner 120 is mounted at generally the center of throat 110 in outlet ring section 104 at the interface between nozzle 100 and sulfur furnace 80. In this 11 embodiment, sulfur furnace 80 with nozzle 100 combines the functions of 12 heater/burner 58 and sulfur furnace 60 of Fig. 2.
13 In operation, combustion air is blown into inlet 109 of cylindrical 14 passageway 108 by process blower 68 (Fig. 2) and forced through passageway 108 into generally conical throat section 110 where it is heated by burner 120 16 and flows out into the interior of sulfur furnace 80. Granulated sulfur is 17 blown into passageway 116 in inlet ring section 102 through inlet 112 by 18 sulfur exhauster 56 (Fig. 2). The granulated sulfur is forced through 19 passageway 116 into swirl or cyclone passageways 118 in outlet ring section 104 which impart a swirl or cyclone effect to the granulated sulfur so that it 21 is swirling as it flows out of passageways 118 into the interior of sulfur 22 furnace 80. When the granulated sulfur flows into furnace 80, it contacts the 23 hot combustion air that has been heated by burner 120 and combusts at 24 generally the interface between nozzle 100 and furnace 80 into S02.
Referring to Fig. 5, atomizing nozzle 200 for use with emulsoid sulfur 26 feedstock is shown. Atomizing nozzle 200 has an outer hollow cylindrical 27 case 202, an inner cylindrical spray head 204, and a web section 206 28 extending between outer case 202 and cylindrical spray head 204 to hold 29 cylindrical spray head 204 in place in outer cylindrical case 204. Web section 206 includes passageways (not shown) which extend therethrough to allow 31 combustion air to flow through outer cylindrical case 202 around spray head 215 813 ~.
- to -1 204 into the interior of sulfur furnace 80. Outer, hollow cylindrical case 2 has an inlet 203 which is coupled to the outlet of heater/burner 58 (Fig.
2).
3 Cylindrical spray head 204 has an inlet end 208 and an outlet end 210.
4 An emulsoid sulfur passageway 212 extends from an emulsoid inlet 214 in inlet end 208 through cylindrical 'spray head 204 to outlet end 210. Emulsoid 6 inlet 214 is coupled by a pipe 2'16 to sulfur pump 72 (Fig. 2). An atomizing 7 air passageway 218 extends from an atomizing air inlet 220 in inlet end 208 8 through cylindrical spray head 204 to outlet end 210. Atomizing air inlet 9 is coupled to the source of atomizing air 74 (Fig. 2). Atomizing air passageway 218 and emulsoid sulfur passageway 212 join at the outlet end 210 11 of cylindrical spray head 204 and open into the interior of sulfur furnace 80.
12 In operation, emulsoid sulfur is pumped from emulsoid sulfur source 13 70 by sulfur pump 72 into emulsoid sulfur passageway 212 in spray head 204 14 of nozzle 200 through emulsoid sulfur inlet 214. Atomizing air is blown by atomizing air source 74 (Fig. 2) into atomizing air passageway 218 in spray 16 head 204 through atomizing air inlet 220. Hot combustion air, which has 17 been heated by heater/burner 58, flows into inlet 203 in outer casing 202 of 18 nozzle 200. The hot combustion air flows through outer casing 202 around 19 spray head 204 and out into sulfur furnace 80. The atomizing air and emulsoid sulfur mix at the outlet end 210 of spray head 204 and the atomizing 21 air/emulsoid sulfur mixture is sprayed by spray head 204 out into sulfur 22 furnace 80 where it contacts the hot combustion air which causes the sulfur 23 particles in the emulsoid sulfur to combust as well as evaporating the water 24 in the emulsoid sulfur. The sulfur particles combust into S4z which then flows from sulfur furnace 80 into catalytic converter 62 (Fig. 2) which 26 catalyzes the SOz into S03. The S03 is then injected into the electrostatic 27 precipitator (not shown) of the electrostatic flue gas pollution control system 28 (not shown) by probes 64 (Fig. 2).
29 Referring to Fig. 6, a system 300 for generating sulfur dioxide in accordance with the invention is shown. Sulfur dioxide generating system 300 31 includes a source of granulated sulfur, such as hopper 302 in which granulated 32 sulfur is held. Hopper 302 can illustratively be a Transilo inerting tank sold WO 94/20414 21 ~ 813 .~ ~T~S94/01973 1 by Jim Pyle, Production Design Co. , Box 462, 544 Aspen Hall, Harrodsburg, 2 Kentucky 40330. However, if inerting of the granulated sulfur is not 3 requireri, hopper 302 can be a hopper or silo of conventional design for 4 holding granulated material.
Hopper 302 has an outlet 304 coupled to an inlet 306 of a pneumatic 6 feed unit 308. Pneumatic feed unit 308 is illustratively a RotoFeedm 7 pneumatic conveying unit manufactured by Simon Air Systems, P. O. Box 8 326, Milford, Ohio 45150. Pneumatic feed unit 308 has a pneumatic feeder 9 310 having a conveying air inlet 312 coupled to a source of compressed air (not shown) by air line 316. Pneumatic feeder 310 of pneumatic feed unit 308 11 has a material outlet 314 coupled by pipe 318 'to an inlet 320 of a sulfur 12 furnace 322.
13 In operation, granulated sulfur is stored in hopper 302. Illustratively, 14 pneumatic feed unit 308 is mounted to the bottom of hopper 302 with its inlet 306 coupled to the outlet 304 of hopper 302 so that granulated sulfur is fed 16 into pneumatic feed unit 308 by gravity or by gravity assist. Pneumatic feeder 17 310 of pneumatic feed unit 308 pneumatically feeds the granulated sulfur to 18 sulfur furnace 322. Illustratively, pneumatic feeder 310 blows the granulated 19 sulfur through pipe 318 at a rate of about 4 CFM which is sufficiently fast to eliminate any explosion hazard which might be caused by sulfur dust.
21 Sulfur furnace 322 combusts the granulated sulfur fed to it by 22 pneumatic feed unit 308 which generates sulfur dioxide. The sulfur dioxide 23 flows out of sulfur furnace 322 through an outlet 324 of sulfur furnace 322.
24 Depending on the type of granulated sulfur used, hopper 302 and pneumatic feed unit 308 may require inerting. If inerting is required, then a 26 Transilo tank discussed above can be used as hopper 302. Pneumatic feed 27 unit 308 then preferrably has an inert gas inlet 326 coupled by a pipe 330 to 28 a source of inert gas, such as a tank of nitrogen 332.
29 Sulfur furnace 322 can be any sulfur furnace which can combust granulated sulfur. For example, sulfur furnace 322 can be sulfur furnace 80 31 shown in Fig. 3 or sulfur furnace 400 shown in Fig. 7.
1 A modification to system 300 is shown in phantom in Fig. 6 in which 2 the granulated sulfur is pulverized into finely divided sulfur, e. g. , 300 mesh, 3 immediately before the sulfur is introduced into furnace 322. In this modified 4 embodiment, a pulverizer 326 is coupled between pipe 318 and inlet 320 of sulfur furnace 322. Illustratively, pulverizer 326 is mounted to the inlet 320 6 of sulfur furnace 322. ' " Granulated sulfur supplied through pipe 318 is 7 introduced into pulverizer 326 which pulverizes it into finely divided sulfur 8 (300 mesh). The pulverized sulfur is then introduced into sulfur furnace 322 9 where it combusts. Pulverizer 326 can illustratively be commercially available ball or ring pulverizes of small capacity, e. g. , 10 - 200 pounds/hour. Such 11 a pulverizer can be an Atritor Cell Mill model 250 manufactured by Allis 12 Mineral Systems Division of Kennedy Van Saun, 350 Railroad Street, 13 Danville Pennsylvania, U.S.A. 17821-2046. By pulverizing the granulated 14 sulfur before it is introduced into furnace 322, granulated sulfur in any commercial form, such as flake, prill, pellet or BB's can be stored and 16 conveyed to the pulverizer 326. The pulverized sulfur flows, illustrativley by 17 pneumatic conveyance, from the pulverizer 326 into furnace 322 at a rate 18 sufficient so as to eliminate the risk of explosion due to sulfur dust. A
day 19 hopper, such as described below with reference to Fig. 8, may be provided in proximity to the pulverizer wherein the granulated sulfur is fed to the day 21 hopper and the day hopper provides the granulated sulfur to pulverizer 326 for 22 pulverizing. Pulverizing the granulated sulfur before introduction into the 23 sulfur furnace is advantageous in that the finely divided sulfur produces the 24 most vigorous flame and requires the smallest furnace envelope, resulting in improved process economies.
26 Fig. 7 shows a sulfur furnace 400 which can be used for sulfur furnace 27 122 of Fig. 6, or for sulfur furnace 60 of Fig. 2. Sulfur furnace 400 is 28 illustratively a spherical array checker work sulfur furnace and comprises an 29 outer shell or casing 402 and an inner casing or shell 404 having a refractory lining 406, such as ceramic, therebetween. Illustratively, outer shell 402 is 31 made of a schedule 40 mild steel and inner shell 404 is made from a 20 gauge 32 mild steel. Refractory lining 406 can illustratively be a castable lining such WO 94120414 g I ~ ~ PCT/US94I019'73 1 as described above with regard to lining 86 of furnace 80 (Fig. 3). Outer 2 casing 402 is illustratively insulated for personnel protection.
3 Furnace 400 further has an inlet 408 and an outlet 410. Inlet 408 4 illustratively has a six inch pipe "T" 409 affixed thereto having a sulfur inlet end 412 and a hot gas inlet end 414. Hot gas inlet end 414 is coupled to a 6 source of hot gas, such as heater 58 (Fig. 2). Hot gas inlet end 414 7 illustratively has baffles 415 affixed therein for imparting a swirl or cyclonic 8 effect to the hot gas flowing thereinto. Pipe 318 (Fig. 6), which is coupled 9 to the material outlet 314 of pneumatic feed unit 308, extends into pipe "T"
409 through sulfur inlet end 412 to the inlet 408 of sulfur furnace 400.
11 Furnace 400 further incudes a checker work array 418 of ceramic balls 12 420 disposed therein. Illustratively, a stainless steel grate 422 extends 13 transversely across the interior of furnace 400 and holds the checker work 14 array 418 of ceramic balls 420. Ceramic balls 420 are illustratively two inch ceramic balls. Although furnace 400 is shown horizontally in Fig. 7, it is 16 preferrably mounted vertically in actual use.
17 In operation, granulated sulfur is supplied by pipe 318 to the inlet 408 18 of furnace 400 where it is blown into the interior of furnace 400 against 19 ceramic balls 420. Hot gas is introduced to the interior of furnace 400 through hot gas inlet 414 of pipe "T" 409. Baffles 415 impart a swirl or 21 cyclonic effect to the hot gas which aids in dispersing the granulated sulfur 22 against ceramic balls 420 in the interior of furnace 400. The hot gas raises 23 the temperature of the ceramic balls 420 to a sufficient level to combust the 24 granulated sulfur. The granulated sulfur combusts after being blown onto the surfaces of ceramic balls 420 and generates sulfur dioxide. After furnace 400 26 has been combusting the granulated sulfur for a sufficient period of time, the 27 heat generated by the combustion of the granulated sulfur is sufficient to 28 maintain combustion so that hot gas no longer need be introduced through hot 29 gas inlet 414 of pipe "T" 409. The gaseous sulfur dioxide exits through outlet 410 of furnace 400 and through pipe 424 which is coupled to outlet 410. Pipe 31 424 is illustratively an eight inch pipe.
1 Fig. 8 is a schematic of a system 500 for generating sulfur dioxide at 2 multiple locations according to the invention. System 500 is a modification 3 of system 300 of Fig. 3 and like elements are identified with like reference 4 numbers. System 500 includes hopper 302 having its outlet 304 coupled to an inlet of a conveyor 502. Conveyor 502 is illustratively a dense phase 6 conveyor such as a Model DPG-1B Cyclonaire Bottom Discharge Dense Phase 7 Conveyor, manufactured by Cyclonaire, Box 366, York, Nebraska 68467, or 8 a Densairveyor manufactured by Simon Air Systems. An outlet of conveyor 9 502 is coupled to inlets 306 of pneumatic feed units 308. A storage hopper or day hopper is provided in proximity with each sulfur furnace 322 for 11 holding a quantity of granulated sulfur such as might be used in one day.
12 Illustratively, the storage hopper or day hopper is part of pneumatic feed unit 13 308 such as indicated by reference number 309. The material outlet 314 of 14 each pneumatic feed unit 308 is coupled to a respective inlet 320 of a respective sulfur furnace 322. Sulfur furnaces 322 with their associated 16 pneumatic feed units 308 can be located at different locations. Further, more 17 than two sulfur furnaces 322 with associated pneumatic feed units 308 can be 18 used in system 500, with the size of hopper 302 and conveyor 502 modified 19 accordingly to accommodate the number of sulfur furnaces 322 and associated pneumatic feed units 308 included in system 500.
21 The use of solid granulated sulfur feedstock or emulsoid sulfur 22 feedstock provides significant advantages over the use of elemental sulfur 23 feedstock which has been heretofore been used to generate sulfur dioxide, 24 such as in S03 flue gas conditioning systems. Emulsoid sulfur is a suspension of water and very fine sulfur particles on the order of four to six microns.
26 The emulsion contains around seventy percent sulfur and thirty percent water 27 which permits the emulsoid sulfur to be handled as a liquid. Moreover, the 28 need for special steam heating of the type required with elemental sulfur is 29 eliminated. All that is required is a simple heating system to keep the emulsoid sulfur from freezing such as heat tape disposed around emulsoid 31 sulfur source 70 (Fig. 2). Further, because emulsoid sulfur is about thirty 32 percent water, there is no risk of explosion. Similarly, the granulated sulfur _._ WO 94/20414 215 8131 ~T~S94101973 1 feedstock, being a solid, eliminates the need for the special steam heating 2 needed for elemental sulfur.
3 The granulated sulfur feedstock system and emulsoid sulfur feedstock 4 system described herein can be advantageously used in any system which requires the generation of sulfur dioxide, such as in new sulfur trioxide flue 6 gas conditioning systems and in the retrofit of existing sulfur trioxide flue gas 7 conditioning systems by replacing the elemental sulfur feedstock system with 8 the granulated sulfur feedstock system or emulsoid sulfur feedstock system of 9 this invention.
Although the invention has been described in detail with reference to 11 certain preferred embodiments, materials and specific examples, variations and 12 modifications exist within the scope and spirit of the invention as described 13 and as defined in the following claims.
Claims (18)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A flue gas conditioning apparatus for conditioning the flue gas flowing in a flue from a boiler to an electrostatic precipitator by injecting sulfur trioxide into the flue gas upstream of the electrostatic precipitator, comprising a. a source of granulated sulfur;
b. a sulfur furnace for combusting the granulated sulfur to generate gaseous sulfur dioxide;
c. transport means coupled to the source of granulated sulfur and the sulfur furnace for transporting the granulated sulfur to the sulfur furnace;
d. a catalytic converter coupled to the sulfur furnace for generating sulfur trioxide from the sulfur dioxide generated by the sulfur furnace; and e. a plurality of injection probes mounted in the flue duct upstream of the electrostatic precipitator and coupled to the catalytic converter for injecting the sulfur trioxide generated by the catalytic converter into the flue gas flowing though the flue duct.
b. a sulfur furnace for combusting the granulated sulfur to generate gaseous sulfur dioxide;
c. transport means coupled to the source of granulated sulfur and the sulfur furnace for transporting the granulated sulfur to the sulfur furnace;
d. a catalytic converter coupled to the sulfur furnace for generating sulfur trioxide from the sulfur dioxide generated by the sulfur furnace; and e. a plurality of injection probes mounted in the flue duct upstream of the electrostatic precipitator and coupled to the catalytic converter for injecting the sulfur trioxide generated by the catalytic converter into the flue gas flowing though the flue duct.
2. The flue gas conditioning apparatus of claim 1, further comprising a source of process air coupled to the sulfur furnace and a heater for heating the process air so that it is at an appropriate temperature when it enters the sulfur furnace to cause the granulated sulfur to combust.
3. The flue gas conditioning apparatus of claim 2 wherein the transport means comprises means for pneumatically conveying the granulated sulfur from the granulated sulfur source to the sulfur furnace.
4. The flue gas conditioning apparatus of claim 3, further comprising a pulverizer coupled to the sulfur furnace for pulverizing the granulated sulfur and injecting the pulverized sulfur into the sulfur furnace.
5. The flue gas conditioning apparatus of claim 1, further including a nozzle mounted at an inlet of the sulfur furnace, the nozzle having a body having an inlet coupled to the transport means, an outlet opening at the inlet of the sulfur furnace, and a swirl passageway formed in the nozzle body extending between the inlet and outlet in the nozzle body for imparting a swirl to the granulated sulfur as it flows through the swirl passageway such that the granulated sulfur is swirling as it enters the sulfur furnace from the outlet in the nozzle body.
6. The flue-gas conditioning apparatus of claim 5 wherein the sulfur furnace includes an inner and outer shell having a refractory lining therebetween, the inner shell defining a cavity in which a checker work array of ceramic balls is disposed, the granulated sulfur being dispersed against the ceramic balls as the granulated sulfur flows into the furnace and combusting thereon.
7. The flue gas conditioning apparatus of claim 6 wherein the granulated sulfur source includes means for maintaining the granulated sulfur in an inert environment.
8. The flue gas conditioning apparatus of claim 1 wherein the sulfur furnace includes an inner and outer shell having a refractory lining therebetween, the inner shell defining a cavity in which a checker work array of ceramic balls is disposed, the granulated sulfur being dispersed against the ceramic balls as the granulated sulfur flows into the furnace and combusting thereon.
9. The flue gas conditioning apparatus of claim 8 wherein the sulfur furnace has an inlet having as inlet pipe affixed thereto, the inlet pipe having an first inlet coupled to the conveying means and a second inlet coupled to a source of hot process air, the second inlet including baffles for imparting a swirl to the process air as it flows into the inlet pipe for mixing with the granulated sulfur to aid in dispersing the granulated sulfur against the ceramic balls of the sulfur furnace.
10. The flue gas conditioning apparatus of claim 9 wherein the sulfur furnace further includes a stainless steel grate extending transversely across the interior of the inner shell for holding the ceramic balls.
11. The flue gas conditioning apparatus of claim 6, further comprising a pulverizer coupled to the sulfur furnace for pulverizing the granulated sulfur and injecting the pulverized sulfur into the sulfur furnace.
12. The flue gas conditioning apparatus of claim 1 wherein the granulated sulfur comprises sulfur in the form of any of powder, prill, flake, pellets, and BB's.
13. A flue gas conditioning apparatus for conditioning the flue gas flowing in a flue duct from a boiler to as electrostatic precipitator by injecting sulfur trioxide into the flue gas upstream of the electrostatic precipitator, comprising:
a. a source of granulated sulfur;
b. a sulfur furnace for combusting the granulated sulfur to generate sulfur dioxide, the sulfur furnace comprising a hollow shell defining a cavity therein with an array of ceramic balls disposed in the cavity wherein the granulated sulfur is dispersed against the ceramic balls as it flows into the sulfur furnace and combusts thereon;
c. a pneumatic conveyor coupled to the granulated sulfur source and to the sulfur furnace for conveying the granulated sulfur from the granulated sulfur source to the sulfur furnace;
d. a catalytic converter coupled to the sulfur furnace for generating sulfur trioxide from the sulfur dioxide generated by the sulfur furnace; and e. a plurality of injection probes mounted in the flue duct upstream of the electrostatic precipitator and coupled to the catalytic converter for injecting sulfur trioxide into the flue gas.
a. a source of granulated sulfur;
b. a sulfur furnace for combusting the granulated sulfur to generate sulfur dioxide, the sulfur furnace comprising a hollow shell defining a cavity therein with an array of ceramic balls disposed in the cavity wherein the granulated sulfur is dispersed against the ceramic balls as it flows into the sulfur furnace and combusts thereon;
c. a pneumatic conveyor coupled to the granulated sulfur source and to the sulfur furnace for conveying the granulated sulfur from the granulated sulfur source to the sulfur furnace;
d. a catalytic converter coupled to the sulfur furnace for generating sulfur trioxide from the sulfur dioxide generated by the sulfur furnace; and e. a plurality of injection probes mounted in the flue duct upstream of the electrostatic precipitator and coupled to the catalytic converter for injecting sulfur trioxide into the flue gas.
14. The flue gas conditioning apparatus of claim 13 further comprising an inlet pipe coupled between an inlet of the sulfur furnace and the pneumatic conveyor, the inlet pipe-having a first inlet coupled to the pneumatic conveyor and a second inlet coupled to a source of hot process air, the second inlet including baffles for imparting a swirl to the process air as it flows into the inlet pipe for mixing with the granulated sulfur to aid in dispersing the granulated sulfur against the ceramic balls of the sulfur furnace.
15. The flue gas conditioning apparatus of claim 13 wherein the granulated sulfur comprises sulfur in the form of any of powder, prill, flake, pellets, and BB's.
16. The flue gas conditioning apparatus of claim 12 wherein the granulated sulfur source includes means for maintaining the granulated sulfur in an inert environment.
17. A flue gas conditioning apparatus for conditioning flue gas flowing in a plurality of flue ducts by injecting sulfur trioxide into the flue gas, each flue duct coupling a boiler to as electrostatic precipitator, comprising:
a. a source of granulated sulfur;
b. a plurality of sulfur furnaces for combusting the granulated sulfur to generate gaseous sulfur dioxide;
c. a day hopper for holding a supply of granulated sulfur located in proximity to each sulfur furnace, each day hopper coupled to the sulfur furnace located in proximity to it for supplying granulated sulfur to the sulfur furnace;
d. transport means for transporting granulated sulfur from the granulated sulfur source to each day hopper;
e. each sulfur furnace coupled to a catalytic converter, each catalytic converter generating sulfur trioxide from the sulfur dioxide generated by the sulfur furnace to which it is coupled; and f. each flue duct having a plurality of injection probes mounted thereto upstream of the electrostatic precipitator to which that flue duct is coupled, each plurality of injection probes coupled to one of the catalytic converters such that each catalytic converter is coupled to an individual set of the probes.
a. a source of granulated sulfur;
b. a plurality of sulfur furnaces for combusting the granulated sulfur to generate gaseous sulfur dioxide;
c. a day hopper for holding a supply of granulated sulfur located in proximity to each sulfur furnace, each day hopper coupled to the sulfur furnace located in proximity to it for supplying granulated sulfur to the sulfur furnace;
d. transport means for transporting granulated sulfur from the granulated sulfur source to each day hopper;
e. each sulfur furnace coupled to a catalytic converter, each catalytic converter generating sulfur trioxide from the sulfur dioxide generated by the sulfur furnace to which it is coupled; and f. each flue duct having a plurality of injection probes mounted thereto upstream of the electrostatic precipitator to which that flue duct is coupled, each plurality of injection probes coupled to one of the catalytic converters such that each catalytic converter is coupled to an individual set of the probes.
18. The flue gas conditioning apparatus of claim 7 wherein the sulfur furnace further includes a stainless steel grate extending transversely across the interior of the inner shell for holding the ceramic balls.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002158131A CA2158131C (en) | 1991-12-18 | 1991-12-18 | Sulfur dioxide generation using granulated or emulsoid sulfur feedstock |
Applications Claiming Priority (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002098989A CA2098989C (en) | 1991-01-03 | 1991-12-18 | Process and intermediates for preparing azabicyclo(2.2.2)octan-3-imines |
| CA002158131A CA2158131C (en) | 1991-12-18 | 1991-12-18 | Sulfur dioxide generation using granulated or emulsoid sulfur feedstock |
| US3181993A | 1993-03-12 | 1993-03-12 | |
| US08/031,819 | 1993-03-12 | ||
| PCT/US1994/001973 WO1994020414A1 (en) | 1993-03-12 | 1994-03-04 | Sulfur dioxide generation using granulated or emulsoid sulfur feedstock |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002098989A Division CA2098989C (en) | 1991-01-03 | 1991-12-18 | Process and intermediates for preparing azabicyclo(2.2.2)octan-3-imines |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2158131A1 CA2158131A1 (en) | 1994-09-15 |
| CA2158131C true CA2158131C (en) | 1999-09-14 |
Family
ID=29402843
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002158131A Expired - Fee Related CA2158131C (en) | 1991-12-18 | 1991-12-18 | Sulfur dioxide generation using granulated or emulsoid sulfur feedstock |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2158131C (en) |
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1991
- 1991-12-18 CA CA002158131A patent/CA2158131C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CA2158131A1 (en) | 1994-09-15 |
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