CA1200102A - Process and apparatus for generating synthesis gas - Google Patents

Abstract

PROCESS AND APPARATUS FOR GENERATING SYNTHESIS GAS

ABSTRACT OF THE DISCLOSURE
The disclosure relates to a process for generating synthesis gas (CO + H2) by subjecting fine particulate materials rich in carbon to an autothermal gasification reaction with oxygen. More particularly, coal dust having a particle size of up to 0.1 mm and oxygen and, if desired, a gaseous addend are injected into a gasification zone main-tained at 2000 to 2600°C; resulting flue dust-containing crude synthesis gas with its inherent thermal energy is passed first through a reduction zone having the feed materials necessary for initiating an endothermal carbothermal re-duction placed therein, and then together with the synthe-sis gas produced during the carbothermal reduction through a pre-heating zone disposed directly above the reduction zone and having the same materials as this latter zone placed therein; next, the synthesis gas is removed at a tempera-ture of 300 up to 1500°C for purification and conversion;
and the fused reaction product originating from the carbo-thermal reduction and fused slag are taken from a collect-ing and post-reaction zone, below the reduction zone.

Description

~ HOE 81/H 023 It has been described that materials rlch in carbon, especiall~ coke and coal, can be subjected to autothermal gasi~ication with the use of commercially pure oxygen or a mixture o~ oxygen and gaseous addend3, preferably steam, nitrogen or carbon dioxide. The gasi~ication is effected inside su~table reaction chambers of different configura tion so that it is possible ~or it to occur e.g. as a ~low bed or ~ixed b~d gasi~ication at atmospheric or elevated pressure. Hereto~ore the materials rich in carbon have been used in admixture with addends which were primarily intended fa~orably so act upon the physical properties of resulting slag.
More particularly, a process ~or generating synthesls gas or fuel gas by sub~ectin~ solid combustibles to gasi~i-catlon with oxygen at temperatures o~ 1200 u~ to l375C, wherein a ilux, e.g. lime~ may be used to reduce the melt-ing temperature o~ the slag, has been described in DE-PS
1 068 415.
A ~urther process ~or ge~erating reduction gas for use in the production o~ iron, wherein solid carbc~aceous combustibles are gasi~ied with air in a ~luidi~ed bed at 1000 up to 1500C, provides for the combustibles to be used in admi~ture~with limestone, lime or materla's con-t~ln~nE silicic acid or alu~ina in quantities permi~ti~g the meltlng point of slag to be increas2d beyond working ~emperature (c~. D~-AS 1 508 083~.
A stlll further process, wherei~ coal cont~i n i ng sul-fur is gasifled inside a`reactor ha~ing an iron bath placed in it 9 which is admixed with lime 7 li~estone or do1omi~e :~2~

in an attempt to produce a desulfuriz.ing slag has been described in DE-AS 25 20 584.
Still other processes for generati~g gas, wherein steam is introduced at 775 up to 980C into a mixture of carbonaceous solid combustible matter and calcium oxide or llme a~d wherein the quantity of calcium oxide or lime present in the reactlon zone is sufficient to con~ert praktically all of resulting carbon dioxide to carbonate ha~e been described in DE-PS 930 5~9 and DE-PS 1 012 420.
Yet another process has been described, wherein coke and lime are dispersed in steam and reacted with oxygen at 1650 up to 2750C inside a flow bed reactor wi~h the resultant formation of calcium carbide and synthe~is gas (C0~2) (cf. US-PS 3 017 259). By means of a hydrocarbon oil, the reaction products are cooled down to less than 425C, a calci~m carbide suspen~ion being separated from the synthesis gas~
In the process of this invention, use is made of se-lected addends which by chemical reaction combine with a~ least several constituents of the ach or slaæ origina-ting from the minerals contained in coal, technochemically useful products, so-called valuable material, being prod-uced in a secondary reaction~ More spec~ically, the addends are preheated to the neces~sary tempe~ature by means o~ the ho~ synthesis gas, the energy required to be used for e~
fecting the endo~hermal secondary reaction being fully taken from a portion o~ the ener~y which is set ~`ree during the autothermal gasification. The secondary product is ~aken ~rom the ~eactor in the form sf a melt.

It is generally accepted that primarily the fossil solid carbon carriers, e.g. coal and lignite or coke made therefrom, have greatly dif~erent proportions o~ ballast material contained in them. The ballast materials chie~ly consist of a plurality of minerals ~hich are partially present in intimate admixture with the carbon and, as residue on ignition, form the ashes. Ash could be evidenced to contain more than 35 elemer,ts, a fact which has always be~n an interesti~g invitation to the reco~ery of raw ma-terials there~rom. Up to date, however, no process hasgained commercial importance. The reason ~or this basically resides ln the fact that ~he ashes generally contain very minor proportions of valuable steel-refining metals which in turn have been most interestlng heretofore, while the principal minerals have been extensively ignored. Although flue dust and granulated ashes are indeed use~ul in the building material industries, the fact rem~ns that the disposal o~ the quantities o~ slag and ash obtair.ed to-day in energy generating stations, of which up to about 75 %
(originating ~rom coal) and mer~ly up to 8 96 (originatlng ~`rom lignite) can be utilized has become a serious problem.
The problem will become even more serious in future upon ~tart up of operation in commercial coal gasification plants inasmuch as the strong concentration of heavy metals and rad~o nucleides in the ash or slag ~orbids uslng them in certain ~ields. On the othsr hand, the utilizatlon capac~ty can be said to be exhausted while even more ashes and slag will be obtained by the gasification of coal.

In the coal gasification plants under operation, ~ery high temperatures generally prevail at the place o~ ash and slag ~ormation, the ash or slag being nor-mally in the ~orm of a melt. The minerals co~tained in coal, chiefly ilite and kaolinite as clay minerals, se-rizide as mica mineral,pyrite 9 marcasite, limonite, he-matite and slderite as iron mi~erals, dolomite, ancerite, calcite as phosphor-minerals and quartz, and a series o~
~urther rarer-to-~ind oxides, hydroxides and sul~ides as well as certain salts beha~e differently dep~n~in~ on the heating rate and atmosphere. On heating, absorbed water is generally expelled ~irst, expelled next is the water of crystallization and then water from OH-groups and car-bon dioxide fr~m carbo~ates. ~instinctly noticeable at tem-peratures higher than 1500C is a transport oi severaloxides ~ia the.gas phase accompanied by the formation of gas comple~es, monoxides or sul~ides which,after reverse reac-tion, give rise to the formation of aerosols. This is more par ticularly true concerning silicon dioxide, aluminum oxide and iron oxide. In addition to this, as a result of the high heating rates the minerals become extensi~ely disintegrated to amorphous oxides which are carried along by ~he stream of synthesis gas. A good deal o~ the silicon dioxide becomes initially fused and later ~orms a glassy phase. Unde- strongly reducing conditions, especially in the presence o~ carbo~, it is possible also ~o ~otice the reducticn o~ the me~al ox~des ~o me ! als, esp~cially ~ke formation o~ iron but also of calcium carbide which is intermediaril~ formed ~ia a metallic stage, or the ~or-~2~

mation of ferrosilicon.
These properties of the mineral constltuents of mate-rials rich in carbon, especially coal, are beneficially combined and utilized in the process o~ this invention.
As a result, it is possible:
1. for a good deal o~ slag and ash to be transformed chemicall~ into technochemical products;

2. ~or individual components, e.g. A1203, to become con-csn~rat~d in~ and Yor good hydraulic binder proper-ties to be con~erred upon, a dust ~raction;
. for the gasi~ication heat, which is at an e~pecially high temperature le~el, to be directly used for high t~mperat~r~ reactions;
4. for the carbon dioxide content of the synthesis gas to be kept at a m~nim-l~ value; and 5. ~or a good deal o~ fine dust, ~hioh generally escapes from the reactor to be retained therein and converted by chemical reaction.
To this end~ the in~ention provide~ for the hot syn-the~i~ gas to be introduced, lmmediately after its genera-tion, into a loo~ely aggregated layer o~ a ~.xture of addends.
This addend mixture has a reducing agent, pre~erably carbon in the form o~ coke, low temperature coke, anthracite, char-coal or peat coke ~or slag reduction contained in it. ~ore speci~ically, ~he bulk of partially liquid slag or flue dust particles become precipitated on t~e ~urface o~ the loo~ely aggregated layer whlle ~orming a super~ioial ~ilm thereon. The high temperatures pre~l in~ i~itiate a reac tion and a reduction zone ls bei~g ~ormed. The a~dend mixture becomes consumed and desirable secondary product~

e.g. ferrosilicon or calcium carbide, is obtained. The specific addend quantities, based on the quantity of ma-terial rlch in carbon, can be selected within wide limita.
Reasonably, the quantity of key component (in the ash) which is to undergo reaction defines the minimll~ quanti-ties of addends to be used (c~. ~xample 1), in accordance with the stoichiometry o~ the con~ersion reaction, whilst the quantity of heat set free during the auto-thermal gasificatiorl reaction de~ines the m~X; ml~m quantities of addends to be used (cf. Example 2)~ in accordance with the energy consumption during the conversion reaction.
The invention rela-tes more partlcularly to a process ~or generating synthesis gas (C0 ~ H2) by sub~ecting fine particulate materials rich in carbon to an autothermal gasification reaction with oxygen, if desired in the pre-sence o~ additional gas~ which co~prises: injecting coal dust having a pàrticle size of up to 0.1 mm and the oxygen and, if desired, a gaseous addend into a gasification zone malntai~ed at 2000 to 2600C; pas~ing the resulting flue dust-cont~1n1ng orude synthesis gas wlth its inherent thermal energy .first through a reduction zone having the feed materials necessary for initiating an endothermal carbothermal reduction placed therein~ and ther passi~g it and the synthesis gas produced during the car~thermal reduction through a preheati~g zone disposed directly above the reductio~ ~one and having the same materials as this latter zone placed therein; remcving the synthesis gas at a temperature o~ 300 up to 1500~ C for puri~ica-tio~ and conversion; and remo~ing 9 DelOW the reduction ~o~e, the fused reactio~ product originating from the car-~20~

bothermal reduc~ion and fused slag ~rom a collecting andpost-reaction zone.
Further preferred features o~ the process of this invention provide:
a) for the proportion of ash contained in the in~ected coal dust and in the coal used for initiating the carbothermal reduction to be at least partially used as reactants in the carbothermal reduction;
b) for the crude synthesis gas coming ~rom the preheat ing zone to be freed from solid dust and solid ~lue dust, and ~or the two solid dust components to be at least partially recycled and injected together with ~resh coal du~t into the reduction zone via the gasi~icat~on zone;
c) ~or the feed materials for initiating the carbother-mal reduction to be used in the form o~ particles with a size o~ 10 up to 20 mm or 20 up to 40 mm;
d) ~or the reduction zone to have an open connection rtlnn;n~ to a~ least two gasi~icat~on zones disposed laterally with respect thereto, and also to the pre-heating zone disposed thereabove;
e) ~or the preheating zon~ and reduction zone to be ~ed with coke, iron scrap and, i~ desired, quartz, ~erro-silicon being obtained as the reaction product of the ~5 carbothermal reduction at 130C 7~p to 1800C;
~) for the preheating zone and reduction zone to be ~ed wi-th coke or calclned a~thracite and lime, calcium car~
bide being obtained as the r~act~c~ product o~ the carbothermal reduction at 1800 up to 2300C;
g) ~or the ~reheating zone and rsduct~on zone to be fed with coke, calcium phosphate and quartz, elementary phosphorous being obtained as the reaetion product of the carbothermal reduction at 1300 up to 1700C;
h) for the preheating zone and reduction zone to be fed with coke and oxidic iron ore, metallic iron being obtained as the reaction product of the carbothermal reduction at 1300 up to 1800C;
i) for the gaseous addend to be selected from CO, CO2, N2, steam or cycled synthesis gas;
j) for the oxygen to be used in a stoichiometric excess, based on the oxidation to CO, in the gasification zone; and k) for one of the feed materials for initiating the earbothermal reduction to be introdueed in metered quantities into the preheating zone and reduetion zone, along the inside walls thereof.
The invention also relates to apparatus for earrying out the proeess eomprising: a shaft furnaee which includes an upper elongated preheating chamber, a reduction chamber, and a post-reaction ehamber, each of which opens into the other, the reduction ehamber being intermediate the preheating and post-reaetion ehambers; at least two opposed eylindrieal gasifica-tion chambers laterally adjoining the reduction ehamber and being openly-connected thereto, eaeh of the gasification chambers being provided with a nozzle structure for the joint admission of coal dust and oxygen; an inlet for admission to feed materials initiating the carbothermal reduction and an outlet for the removal of crude synthesis gas at a head o~ the shaft furnace; and at least one slag outlet for the removal of fused slag and fused reaction product originating from the carbothermal reduction, from the post-reaction chamber.

'2 Preferred features of the apparatus of this invention provide:
a) for an intermediate carbon-dust-receiving bunker (2) to be disposed ahead of each nozzle structure (3); for a dust precipitating means (11) to be disposed in the crude synthesis gas outlets (9, 12); lines (13) permitting precipitated mineral dust to be recycled from the dust precipitating means (11) to the individual intermediate bunkers (2);
b) for separating plates (16) defining an annular chamber (6e) formed between themselves and the inside wall of the shaft furnace (6), to be disposed in the upper portion of the shaft furnace (~) in upright and annular fashion; for at least two transport lines (15) to be used for admitting one of the feed materials initiating the carbothermal reduction to the annular chamber (6e), the feed material aggregating around, and protecting, the inside wall of the shaft furnace (6).
The process of this invention can be carried out in various ways. It, and the apparatus used therein, will now more fully be described with, by way of e~ample only, reference to Figures 1 and 2 of the accompanying drawings, in which:
Figure 1 is a diagrammatic representation of one apparatus embodiment according to the present invention; and Figure 2 is a diagrammatic representation of a modification of the apparatus of Figure 1.
The material rich in carbon (coal dust) which is to undergo gasification is hereinafter briefly termed gasification coal.
Figure 1 Most finely ground and predried gasification coal (particle size- 90% = ~90/um) ls introduced through feed ;,~

lines (1) and intermediate bunkers (2) into dust gasifi-cation burners (3). Next, it is injected together with oxygen coming from conduit (4) and ga~eous addend, if desired, especially carbon dioxide9 steam, carbon mon-oxide or crude synthesis gas coming from conduit (5) intogasification zone (6a) of the reactor space of this in-vention (shaft furnace) (6) and subjected to autothermal ~asificatlon therein. The i~ention incidentally pro~i-des for oxygen and/or the gaseous addend to be used as a carrier gas for the gasification coal. In accordance with this invention, the reactor space (shaft furnace) ~6) is provided in axial direction with a reduction zone (6b) ad~oining the gasi~ication zon~ (6a), the reduction zone (6b) belng comprised of a loosely aggregated layer of the r~spective addend mixture. The addends are preferably used in the form o~ particles with a size o~ 10 to 20 mm or 20 to 40 mm. Disposed above said layer of loosely aggregated material is a preheatlng zone (6c) which equally has a layer of loosely aggregated addend mixture placed in it so that it i5 pOSS~ 1~ for the latter, under the action o~ gravlty, to ~ra~el downwardly in accordance with the consumption of material ir~ the reduction zone (6b). Dis-posed below the reduction zone (6b) i5 a collecting and post-reaction zone (6d) into which is dropped molten ~lag and reduction product coming from the reduction zone (6b).
The collectlng and post-reaction zone (6dj is formed wlth at least one cl~sa~le tapping hole p~rmitting mo1ten slag and molten reductlon product to be t~ken therefrom and to be removed through lines (7a) and~or ~7b), ~hich can be granulated or allowed to cool in suitable containers.
A temperature o~ about 2000 to 2600C is established in the gasi~ication zone (6a) with the aid o~ the gaseous addend, whilst a temperature o~ 1300 to 2300C is ~ound to establish in the reduction zone (6b). The addend mixture contain a reductant, preferably coke, low temperature coke, anthracite, charcoal or peat coke, and further materials typical of the desired reaction. The reductants contain ~olatile constituen~ to such extent only that their degasification or reaction products (e.g. hydrocar-bons, tar) are not liable to a~ect the processing of the generated synthesis gas. It is nqturally possible to use the reductant in the form of calcined material. The gasi-~ication products obtained in gasification zone (6a) are forced to travel through the reduction zone (6b3 and pre-heating zone (6c) in which their inherent heat is trans ferred to the addend mixture; they issue from the upper port~on of the reaction space with a temperature o~ about 300 to 1 500C . Depending on the quantity of reduction pro-~o duct which is desired to be produced and/or on the tempe-rature desired for the issuing crude gas, it ~s possible for the quantity and composition of the addend mixture ta be varied. The crude s~nthesis gas has been found to issue ~ith a minimum temperature in the e~ent of the materlal loosely aggregated in the preheating zone providing a ~ery large sur~ace area ~or heat exchange, and in the event o~
the energ~ consumsd ~or the reducing reactions correspond-ing to the energy which is set ~ree by the autother~al ga-si~ication reaction. ~isposed near the upper p~rt~on o~

~z~ z the reaction space is a de~ice, pre~erably gas-tightly sealed slides or top smoke stoppers, permîtting the addend mixture travelling through line (8) to be introduced thereinto. As a safeguard against high temperatures o~ the issuing crude s~nthesis gas, outlet (9) may be ~ormed with a waste heat boiler (10) so that it is possible ~or the crude synthesis gas to be freed ~rom dust in hotdust-removing ~eans (11 ) and to be remo~ed through outlet (12).
Dust taken from the hot dust removing means (11) can either be recycled through line (13) and intermediate bunker (2) to the gasification zone (6a) and red~ction æone (6b) or it can be removed through llne (14) or caused to travel, in appropriate quantltative ratios, through lines (13) and (14). In this manner, it is possible to remove all residual ash and ballast ~rom the feed materials in the form of slag through lines (7a) and (7b), respecti~ely, or to remo~e portions thereof in the ~orm of dust from the dust remo~ing means (11) through line (143.
Figure 2 The process described herelnabove with reference to Figure 1 is modi~led. To this end, the invention provides for one of the materials forming the addend mixture to be ~ntroduced through line (15), separately from the other materials ~orming the mixture into the reaction space and~
with the aid o~ auxiliary equipment (16) it is caused to be-come di~tributed i~ columnar or cyllndershaped fashlonO
Oxygen in excess can be admitted to the gasification zone so as to establish high gas temperatures, the outs~de sur~ace o~ the loosely aggregated material in annular cham~
ber (6e3 protectlng the inside wall of the reaction space.

In the following Examples, the volume % were deter-mined at standard conditions at 273 K and 1.013 bar.
Example 1 Synthesis gas was needed for the production of about 52.5 t/h methanol. To this end, it was necessary to gene-rate about 121 000 m3/h CO+H2 by the conversio~ in accor-dance with this in~entio~ of silicon dioxide present in the ash to ~errosilico~ cont~;n~n~ 45 % sio More parti-cularly, predried, most ~inely ground ~particle si7e 90 %
~ 90/um) unwashed crude coal was sub~ected to autothermal gasi~ication with addition o~ predried blast ~urnace coke no. 4 (particle size = 10 to 20 mm) and iron scrap (95 Fe).
More speci~ically, as shown in Figure 1, 60 t/h fine coal dust (particles: 90 ~ ~ 90/um~ was introduced through feed lines (1) lnto bunkers (2). Next, it was admitted to dust gasi~ication burners (3) and gasified together with about 39 290 m3/h ~9.9 ~ oxy~en comi~g from condui-~ (4).
Through line (8), a mixture (particle size = 10 to 20 mm) of coke (for the reduction of SiO~) commlnuted iron scrap, of whlch 4.17 t/h (2.08 t/h coke and 2.09 t/h lron scrap) wa~ consumed, was introduced into sha~ furnace ~6) 50 as to ~orm a layer o~ loosely aggregated material tnerein. In gasification zone (6a) which was add~tion~lly ied with about 5000 m3/h carbon dioxide coming ~rom con~uit (5~, sy~thesis gas was iound to form at temperatures o~ about 2000 to 2300C, whilst the slag in reductior. zone (6b) became reduced. SiO~ as well as Fe203 u~derwent reduct~on a~d ~errosilicon was ~o~nd to ~or~ at about 160aC~ I~

~ Z~3~

was obtained as a ~used mass which dropped through the layer o~ loosely aggregated material lnto the collecting and post-reaction zone (6d), about 4.2 t/h ferrosilicon cont~ ni n~ 45 % Si being taken there~rom through line (7a) and (7b), respectively. Next, the synthesis gas was passed through the layer o~ loosely aggregated addend mixture which became heated to abou~ 1500C, in prehea-ting zone ( 6G )c Fl~e dust which was produced was partlally retained in the loosely aggregated materials, and the re-tained portion was recycled to reduction zone (6b), Thesynthesis gas issued through line (9), waste heat boiler (10) and hot dust-removing means (11). About 122 100 m3/h pr~-dedusted crude ~ynthesis ga~ (about 121 000 m3/h CO~H2) composed of about 76-77 vol~me % COg about 22 volume % H2 and about 1-2 ~olume % N2, the balance being CO~ was ta~en fro~ line (12). Dust precipitated in (11) was partially recycled through line (13). The proportion of dust removed through line (14) contained about 57 weight ~ Al203 chie~ly together with CaO and MgO. The quantity of dust recycled permitted the quantity o~ slag removed from (6d) through (7a) and (7b), respect~ely, to be acted upon. Altogether 4.2 t/h ash and slag were obtained.
About 7.9 t/h ash and slag would be o~tained by custo-mary flow bed gasification. As compared with the prior art, 42 ~ less ash and slag are obtained in the prese~t processO
At the same tlme~ the ~lue dust frac~ion (line 14) contalns an increased proportion of Al~03. This results i~ the for mation o~ a hydraulic product which is use~ul as a binder and in the ~ormat~ o~ of ferrosilico~ cont~in; n~ 45 % Si as desirable valuable reduction product.
Example 2 Ferrosilicon is produced by a high temperature pro cess which has heretofore been carried out in electrother-mal furnaces. The invention now provides for the present process to be further modifled, i.e. for the addend mix-ture to also comprise quartzite as an additional compo-nent, and for the quantity of ferrosilicon to be thereby incrsased. In this manner,it is possible for the bulk of the gasification heat to be obtained in the form of che mically combined energy.
A gas generator was operated in accordance with this invention to produce crude synthesis gas, i.e. about 95 800 m3/h COIH2 for tne opera-~ion of a commercial metha~
nol-producing plant with a capacity of 1000 tons per day.
To this end, as shown in Figure 1, 46.73 t/h unwashed, predried and most finely ground (particles: 90 ~ c 90/um) crude coal flowing through line (1) and bunkers (2) was admitted to the dust gasification burner (3) and subjected to autothermal gasification at 2200 to 2600C with ~he aid of about 32 560 m3 99.9 ~ oxygen, without gaseous addend. The shaft furnace (6~ was ~ed through line (8?
with the addend mixture (particle size = 10 to 20 mm~
consisting o~ about 3.15 t/h blast furnace c~ke no. 4 (predried3, about 7~41 t/h crushed quartzite (95 %) and about 0o67 t/~ iron scrap (lu~py mater~a11 about 95 % Fe)~
Reduction zone ~6b) was maintained ~nder the condi~
tions described in Example 1~ About 5.89 t/h ferrosilieon cont~ni~ 75 % Si was formed thereln, which was intro duced as a ~us~d mass into collecting and post-reaction ~one (6d) from l.Yhich it was removed through lines (7a) and (7b), respectively. Synthesis gas and C0, which was set ~ree during the reaction, travelled in (6c) through the layer o~ addend mixture and cooled down to about 350 - 450C. Next, about 97 050 m3/h pre-dedusted crude synthesis gas (about 95 800 m3/h CO+H2) composed of about 7~ volume % C0, about 21 volume ~ H2 and about 2 volume %
N2, the balance being C02, was removed through line (9) 9 dust precipitating ~eans (11) and line (12). Flue dust enriched with Al203 as in Example 1 was obtained. As i~l Example 1, variable portions thereof were recycled through (13) and (2) to dust gasi~ication burners (3), or removed through (14). Altogether about 3.49 t/h dust and slag were obtained.
This corresponded to only 52 % o~ the quantity of du~t and slag e~ected in standard flow bed gasif~cation.
In addition to this. about 5,89 ~/h ferrosilicon contain-ing 75 % Si was obtained as a valuable reduction product.
Exampl~ ~
By sub~ject~ng coal to gasification in accordance with this in~entlon it ~as also possible, apart ~rom ~errosillcon, to produce - as re~uct~on product - calcium carbide which is norm~1ly made in electrothermal ~urnaces.
Th~ gasification ccal was American ~ibrous coal con-tai~ing about 11.5 weight ~ ash and 2.8 weight % water 9 in the c~ude st~te. The combustible ma~ter of thi~ fibrous coal contained 85.55 weight ~ C, 5.23 weight % H, 6.24 weight % 0, 1.52 weight % N, 1~46 weigh+, % S. The ash ~v~

contai~ed calcium oxide in a proportion as high as about 50 weight %. Calcined anthracite was used as the reductant.
As described in the preceding Examples, 106.~1 t/h predried, most ~inely ground coal dust (particles: 90 ~
smaller than 90tum) was gasified in accordance with this invention at 2200 - 2600C with about 70 720 m3/h 99.9 ~
oxygen. Reduction zone (6b) was fed with an addend mixture of 48.55 t/h 96 % quicklime and about ~6.06 t/h calcined anthracite, and about 60 t/h molten 80 % calcium carbide was obtained at about 2000C. 10.82 t/h dust was removed through (14). About 231 000 m3/h pre-dedusted crude syn-thesis gas which issued from the shaft ~urnace (6) at about 400`C and contained about 73 - 74 volume % C0, 24 - 25 volume ~ H2 and about 1 - ~ volume ~ N2, the balance being C0, was also obtained. The use of the addend mixture with the high content o~ basic addends therein was par~icularly ~a~orable as the crude synthesis gas was practically free from sulfur.

Claims (16)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A process for generating synthesis gas (CO + H2) by subjecting fine particulate materials rich in carbon to an autothermal gasification reaction with oxygen, which comprises:
injecting coal dust having a particle size of up to 0.1 mm and the oxygen into a gasification zone maintained at 2000 to 2600°C;
passing the resulting flue dust-containing crude synthesis gas with its inherent thermal energy first through a reduction zone having the feed materials necessary for initiating an endothermal carbothermal reduction placed therein, and then passing it and the synthesis gas produced during the carbo-thermal reduction through a preheating zone disposed directly above the reduction zone and having the same materials as this latter zone placed therein;
removing the synthesis gas at a temperature of 300 up to 1500°C for purification and conversion; and removing, below the reduction zone, the fused reaction product originating from the carbothermal reduction and fused slag from a collecting and post-reaction zone.

2. A process as claimed in claim 1, wherein a gaseous addend is also injected into the gasification zone.

3. A process as claimed in claim 1, wherein the proportion of ash contained in the injected coal dust and in the coal used for initiating the carbothermal reduction are at least partially used as reactants in the carbothermal reduction.

4. A process as claimed in claim 1, wherein the crude synthesis gas coming from the preheating zone is freed from solid dust and solid flue dust, and the two solid dust compon-ents are at least partially recycled and injected together with fresh coal dust into the reduction zone via the gasification zone.

5. A process as claimed in claim 1, wherein the feed materials for initiating the carbothermal reduction are used in the form of particles with a size of 10 up to 20 mm or 20 up to 40 mm.

6. A process as claimed in claim 1, wherein the reduction zone has an open connection running to at least two gasification zones disposed laterally with respect thereto, and also to the preheating zone disposed thereabove.

7. A process as claimed in claim 1, wherein the preheat-ing zone and reduction zone are fed with coke, and iron scrap ferrosilicon being obtained as the reaction product of the carbothermal reduction at 1300 up to 1800°C.

8. A process as claimed in claim 7, wherein the preheat-ing zone and reduction zone are additionally fed with quartz.

9. A process as claimed in claim 1, wherein the preheat-ing zone and reduction zone are fed with coke or calcined anthracite and lime, calcium carbide being obtained as the reaction product of the carbothermal reduction at 1800 up to 2300°C.

10. A process as claimed in claim 1, wherein the preheat-ing zone and reduction zone are fed with coke, calcium phosphate and quartz, elementary phosphorus being obtained as the reaction product of the carbothermal reduction at 1300 up to 1700°C.

11. A process as claimed in claim 1, wherein the preheat-ing zone and reduction zone are fed with coke and oxidic iron ore, metallic iron being obtained as the reaction product or the carbothermal reduction at 1300 up to 1800°C.

12. A process as claimed in claim 2, wherein the gaseous addend is CO, CO2, N2, or cycled synthesis gas.

13. A process as claimed in claim 1, wherein oxygen is used in a stoichiometric excess, based on the oxidation to CO, in the gasification zone.

14. A process as claimed in claim 1, wherein one of the feed materials for initiating the carbothermal reduction is introduced in metered quantities into the preheating zone and the reduction zone, along the inside walls thereof.

15. An apparatus for carrying out the process as claimed in claim 1, comprising:
a shaft furnace which includes an upper elongated preheat-ing chamber, a reduction chamber, and a post-reaction chamber, each of which opens into the other, the reduction chamber being intermediate the preheating and post-reaction chambers;
at least two opposed cylindrical gasification chambers laterally adjoining the reduction chamber and being openly-connected thereto, each of the gasification chambers being provided with a nozzle structure for the joint admission of coal dust and oxygen and an intermediate carbon-dust-receiving bunker disposed upstream of each said nozzle structure;
an inlet for admission of feed materials initiating the carbothermal reduction and an outlet for the removal of crude synthesis gas at a head of the shaft furnace; a dust precipitat-ing means being disposed in the crude synthesis gas outlets, and lines permitting precipitated mineral dust to be recycled from the dust precipitating means to said intermediate bunkers; and at least one slag outlet for the removal of fused slag and fused reaction product originating from the carbothermal reduction, from the post-reaction chamber.

16. An apparatus as claimed in claim 15, further compris-ing separating plates which, together with an inside wall of the shaft furnace, define an annular chamber, the separating plates being disposed in the upper portion of the shaft furnace in upright and annular fashion; at least two transport lines for admitting one of the feed materials which initiates the carbothermal reduction to the annular chamber, the feed material aggregating around, and protecting, the inside wall of the shaft furnace.