CN101230296A - Reforming reactor and method for preparing synthesis gas from raw biomass gas - Google Patents

Abstract

The invention discloses a reforming reactor and a method for preparing synthesis gas from raw biomass gas. The method comprises the following steps: the high-temperature raw gas obtained by gasifying biomass is separated by a cyclone to remove most of the coke particles; Reactor; add superheated steam and oxygen into the reforming reactor at the same time, under the action of the catalyst in the reforming reactor, the high-temperature raw gas will carry out catalytic reforming in the presence of oxygen at a reaction temperature of 640-850°C, and the orientation It is converted into synthesis gas mainly containing H ₂ , CO, and CO ₂ components; the reformed synthesis gas enters the synthesis system after being cooled and dedusted. The present invention applies the oxygen-adjacent reaction technology to the catalytic reforming process of raw biomass fuel gas to prepare high-grade synthesis gas, which can significantly save energy, reduce consumption and reduce emissions, and prolong the regeneration period and service life of the catalyst. The integrated sustainable utilization of biomass resources-energy-environment has been realized.

Description

Reforming reactor and method for preparing synthesis gas from raw biomass gas

technical field

The invention provides a process and method for efficiently and cleanly producing high-grade biosynthesis gas, and in particular relates to a reforming reactor and method for preparing synthesis gas from raw biomass gas.

technical background

my country is a country with relatively poor oil and gas resources. In recent years, the continuous rise of international oil prices has had an important impact on my country's economy, and has also brought considerable pressure on my country's energy security and national security. Biomass is the only carbon resource that can be converted into liquid fuels in renewable energy. By developing low-cost biomass synthesis gas production technology and using waste biomass resources as raw materials to synthesize high-quality liquid fuels, it is important to realize the diversification of my country's energy structure. It is of great significance to modernize and enhance energy security.

The development and utilization of energy based on fossil fuels emit a large amount of greenhouse gases, toxic and harmful gases, waste residues, waste water, waste oil, etc., which are the main causes of environmental pollution and climate change. As China formally fulfills its obligation to reduce CO ₂ emissions under the Kyoto Protocol, the pressure on China to reduce CO ₂ emissions will increase. The production process of biomass synthetic liquid fuel is friendly to the environment. Therefore, the large-scale development of biomass synthetic fuel industry can greatly reduce CO ₂ emissions, which is one of the most effective ways to fundamentally solve the air pollution and greenhouse effect caused by mineral energy consumption. First, it is conducive to the protection of the ecological environment and the realization of sustainable social development.

At present, countries around the world are currently drawing on the achievements and experience of the natural gas industry, and on the basis of relatively mature biomass gasification engineering technology, extensively carry out the research and development of biomass gas reforming and modulation to produce synthetic gas, so as to meet the needs of downstream liquid fuels. Synthesis system requirements. Since biomass tar is mainly a condensed ring compound with a very complex composition, the reforming process is likely to cause carbon deposition and deactivation of the nickel-based catalyst, which makes the cost of biomass crude gas purification and component reformation adjustment high.

The oxygen reaction technology has been proved to be a very effective method to eliminate the carbon deposition on the surface of the catalyst in many high-temperature reactions that are prone to carbon deposition, and has gradually been widely used in industrial production technology in recent years.

Contents of the invention

One of the objectives of the present invention is to provide a method for producing high-quality synthesis gas from crude gas, which solves the problems of rapid decline in catalytic activity caused by carbon coking on the surface of the catalyst during the reforming process.

To achieve the above object, the present invention adopts the following technical solutions:

A method for preparing synthesis gas from raw biomass gas, comprising the steps of:

(1) The high-temperature crude gas obtained by gasifying biomass is subjected to cyclone separation to remove most of the coke particles;

(2) Send into the reforming reactor again; Add superheated steam and oxygen in the reforming reactor simultaneously, wherein, the crude gas added and _O The molar ratio is 100: 2～6, in every cubic meter of crude gas The amount of added water vapor is 0.12-1.20kg/m ³ ; the high-temperature raw gas is catalytically reformed under the action of the catalyst in the reforming reactor, and is directional converted into a synthesis of components mainly containing H ₂ , CO, and CO ₂ gas; the catalyst is a high-stable nickel-magnesium solid solution catalyst; the reaction temperature of oxygen-catalyzed reforming is between 640 and 850°C;

(3) The synthetic gas produced after reforming is cooled and dust-removed, and then enters the synthesis system.

The preparation method also includes the steps of:

Before catalytic reforming in the presence of oxygen, the reforming catalyst is reduced and activated at a temperature of 700-850° C. for 1-3 hours.

Preferably, the molar ratio of raw gas and _O2 added in the above step (2) is 100:3, the amount of water vapor is 0.8-1kg/ ^m3 ; the reaction temperature is 700-800°C.

Preferably, the high-stable nickel-magnesium solid solution catalyst is prepared by the following method:

(1) Dissolve Ni(AC) ₂ and Mg(NO3) ₂ crystals in distilled water to prepare a solution with a Ni and Mg atomic molar ratio of 2:100 to 5:100 a.

(2) First heat the mixed solution a to 57-62°C, then titrate with an equal volume of 2mol/L K ₂ CO ₃ solution in a beaker under stirring, while keeping the constant temperature of the solution at 57°C, and the titration speed during titration is 10 -15ml/min, the pH value is always kept between 8-10;

(3) After standing still for 1.5-2.5 hours, suction filter, and quickly rinse with hot water at 60°C, and then rinse with a large amount of 0.1mol/l (NH ₄ )HCO ₃ solution to remove K ⁺ ;

(4) Dry at 120°C for 12 hours, then calcinate and co-melt at 950°C for 20 hours, and finally extrude.

Another object of the present invention is to provide a reforming reactor used in the above method for producing synthesis gas from raw biomass gas.

The technical scheme to achieve this purpose is as follows: a reforming reactor, which is provided with an upper partition and a lower partition to divide the space in the reactor from top to bottom into an exhaust chamber, a flue gas chamber, a collector Gray room, at least two reaction tubes are arranged in the flue gas chamber, and the two ends of the reaction tubes respectively pass through the upper partition and the lower partition; a filter screen is provided at the lower port of the reaction tube to separate the space inside the reaction tube from the The ash collection chambers are separated; on the wall of the reactor, there are gas supply ports, crude gas inlets, flue gas inlets, flue gas outlets, and reformed gas outlets; the upper part of the ash collection chambers communicates with the outside world through the gas supply ports and crude gas inlets. The lower part of the flue gas chamber and the upper part of the flue gas chamber communicate with the outside world through the flue gas inlet and the flue gas outlet respectively, and the exhaust chamber communicates with the outside world through the reformed gas outlet.

Preferably, the air supply port includes an oxygen inlet and a water vapor inlet. The bottom of the reforming reactor is provided with an ash outlet through which the ash collection chamber communicates with the outside world.

The present invention applies the oxygen reaction technology to the catalytic reforming process of biomass gas, CH ₄ , C ₂ , C ₃ ... and tar in the biomass gas are selectively converted into H ₂ and CO, and the H ₂ /CO ratio, greatly prolonging the regeneration period and service life of the catalyst, further improving the long-term operation stability of the biomass synthesis gas generation system, reducing the catalyst unit consumption and system maintenance costs, will become an important direction for the research and development of advanced reforming processes one.

The present invention applies the oxygen-adjacent reaction technology to the catalytic reforming process of raw biomass fuel gas to prepare high-grade synthesis gas, which can significantly save energy, reduce consumption and reduce emissions, and prolong the regeneration period and service life of the catalyst. The integrated sustainable utilization of biomass resources-energy-environment has been realized.

Description of drawings

Fig. 1 is the equipment schematic diagram used in the method for preparing syngas of the present invention;

Fig. 2 is in Fig. 1, the structural representation of reforming reactor;

Fig. 3 is among Fig. 2, A-A sectional view;

Description of reference signs

1. Biomass feed system, 2. Fluidized bed gasifier, 3. Cyclone separator, 4. High temperature cracker, 5. Coke feeder, 6. Burner, 7. Reforming reactor, 8. Ash collection chamber of reforming reactor, 9, flue gas chamber 10, reaction pipe, 11, ash outlet, 12, metal filter, 13, flue gas inlet, 14, crude gas inlet, 15, flue gas outlet, 16, Reforming gas outlet, 17. Heat exchanger, 18. Bag filter, 19. Pulse blowback device, 20. Exhaust chamber, 21. Upper partition, 22. Lower partition, G1, gasifier O ₂ inlet G2, gasifier water vapor inlet G3, _O2 inlet G4, water vapor inlet.

Detailed ways

The present invention will be further illustrated in the following examples, but the present invention is not limited.

1: Catalyst preparation

Prepare high stable nickel-magnesium solid solution catalyst as follows:

(1) Dissolve Ni(AC)2 and Mg(NO ₃ ) ₂ crystals in distilled water to prepare a solution with a molar ratio of Ni and Mg atoms of 3.3:100 a.

With 2mol/L K ₂ CO ₃ solution, 0.1mol/L (NH ₄ )HCO ₃ solution.

(2) First heat the mixed solution a to 57+5°C, then titrate with an equal volume of K ₂ CO ₃ solution in a beaker under stirring, while keeping the solution at a constant temperature of 330K (57°C), and control the titration speed during titration , generally controlled at 10-15ml/min, and the pH value is always kept within 8-10.

(3) After standing for two hours, suction filter, and quickly rinse with 60°C hot water, and then rinse with a large amount of 0.1mol/l (NH ₄ )HCO ₃ solution to remove K ⁺ .

(4) Dry at 120°C for 12 hours, and then calcine and eutectic at 1223K (950°C) for 20 hours. Finally extruded. And add it in the reaction tube of the reforming reactor.

2. Reforming reactor

As shown in Figures 1-3, the equipment for preparing synthesis gas from raw biomass gas in this embodiment mainly consists of a biomass feed system 1, a fluidized bed gasifier 2, a cyclone separator 3, a high-temperature cracker 4, and a coke Feeder 5, burner 6, reforming reactor 7, heat exchanger 17, bag filter 18, pulse blower 19, and gasifier oxygen and water vapor inlets G1 and G2. The reforming reactor 7 is a tube-and-tube reactor, and an upper partition 21 and a lower partition 22 are arranged in the reactor to divide the space in the reactor into an exhaust chamber 20 and a flue gas chamber 9 from top to bottom. , the ash collection chamber 8, is provided with twelve reaction tubes 10 (as shown in Figure 3) in the flue gas chamber 9, and the two ends of this reaction tube 10 run through the upper dividing plate 21, the lower dividing plate 22 respectively and are connected with the exhaust gas. Chamber 20 and ash-collecting chamber 8 communicate; a metal filter screen 12 is provided at the lower port position of the reaction tube 10 to separate the space in the tube of the reaction tube 10 from the ash-collecting chamber 8; an _O2 inlet is provided on the wall of the reactor G3, water vapor inlet G4, crude gas inlet 14, flue gas inlet 13 _{, flue gas outlet 15, reformed gas outlet 16; the upper part of the ash collection chamber 8 is connected to the O 2 inlet} pipe, The water vapor intake pipe communicates, the upper part of the ash collection chamber 8 communicates with the crude gas intake pipe through the crude gas inlet 14, the lower part of the flue gas chamber 9 communicates with the flue gas inlet pipe through the flue gas inlet 13, and the upper part of the flue gas chamber 9 passes through the flue gas outlet 15 It communicates with the flue gas outlet pipe, and the exhaust chamber 20 communicates with the reformed gas outlet pipe through the reformed gas outlet 16 . The ash outlet 11 is arranged at the bottom of the reforming reactor 7 , and the ash collection chamber 8 communicates with the outside through the ash outlet 11 .

3. Preparation of synthesis gas from raw biomass gas

The biomass raw material enters the gasifier 2 through the feed system 1, and is ignited and started to produce gas. After the high-temperature gas is separated by a cyclone to remove most of the coke particles, it is directly sent to the burner 6 for combustion. The high temperature cracker 4 is heated to raise the temperature. After reaching the predetermined reforming reaction temperature of 780°C, the high-temperature cracker feed system is turned on, and the biomass raw material is decomposed into coke and volatile matter (gas and oil vapor) by high-temperature cracking, and the coke is sent into the gasification by the coke feeder 5 Furnace 2 is gasified, and the volatile matter is sent to the burner 6 for combustion, and the heat generated is supplied to the reforming reactor 7; at the same time, the high-temperature gas generated by the gasification furnace is gradually switched to the reaction tube 10 of the reforming reactor to reduce the reforming catalyst After activation for 2 hours, the reduction temperature is 780°C.

After the reduction and activation of the reforming catalyst is completed, oxygen with a molar ratio of 100:3 to the high-temperature crude gas is added to the biomass high-temperature gas flow from the oxygen inlet G3, and superheated steam is added from the water vapor inlet G4. The amount of water vapor added is 0.8kg. Under the action of the catalyst, the high-temperature crude gas reacts in the reaction tube 10 at a reaction temperature of 780°C, CH ₄ , C ₂ , C ₃ ... and tar in the crude gas are selectively converted into H ₂ and CO, and discharged from the catalytic bed The high-temperature gas flows through the waste heat boiler 17 for heat exchange and cooling, then enters the bag filter 18, and then is pressurized and sent to the subsequent synthesis system. The synthetic relaxation gas of the synthesis system passes through the pulse blowback device 19 to blow back the reaction pipe 10 and the bag filter 18 at regular intervals to prevent the catalytic bed from being clogged, and the dust and ash content blown back from the reforming reactor is collected in the reforming reactor. Chamber 8 is regularly cleared from the ash outlet 11.

Under the above conditions, the catalytic reforming reaction system has been continuously operated for 300 hours, and the catalyst has not been detected to be deactivated by carbon deposition. The analysis of the composition of the synthesis gas after the reforming reaction shows that the ratio of H ₂ /CO is 1.3, and the content of CH ₄ in the synthesis gas When it is reduced to below 0.2 mol%, the conversion rate of tar in the raw biomass gas reaches over 99%, and the tar content is lower than 0.1 mg/m ³ . The tar components in the syngas after traditional reforming and after oxygen reforming are shown in Table 1.

Table 1 Tar components in syngas after non-oxygen reforming and full oxygen reforming

residual hydrocarbons Non-Oxygen Weight Oxygen weight residual hydrocarbons non-critical oxygen weight Oxygen weight 1-butene 10.30 8.32 Toluene 298.78 82.1 trans-butene 0 0 Ethylbenzene 33.31 0 cis-butene 0 0 m, p-xylene 66.06 0 butane 0 0 Styrene 332.98 0 3-Methyl-1- 6.52 0 O-xylene 38.41 0 1-pentene 11.05 0 2-Methylphenol 34.83 0 2-Methyl-1- 4.58 0 Phenol 19.22 0 Isoprene 8.83 0 1,3-cyclopentene 32.26 0 cis-2-pentene 4.09 0 Methyl isobutyl ether 12.95 0 Cyclopentene 2.69 0 carbonyl sulfide 0 0 2-Methyl-2- 0 0 naphthalene 0 0 benzene 776.11 512.71 methane 4mol% 0.2mol%

Example 2

Catalyst used is identical with embodiment 1.

The catalytic reformer used and the preparation method are basically the same, the difference is that the molar ratio of the crude gas to _O2 added is 100:2, and the amount of water vapor is 0.2kg/ ^m3 ; the high-temperature crude gas is in the reforming reactor Under the action of the catalyst, the reaction temperature is 780°C.

Under the above conditions, the catalytic reforming reaction system has been continuously operated for 300 hours, and the catalyst has not detected carbon deposition and deactivation. The analysis of the composition of the synthesis gas after the reforming reaction shows that the H ₂ /CO ratio is 1.02, and the CH4 content in the synthesis gas is reduced. When it is lower than 0.3 mol%, the conversion rate of tar in the raw biomass gas reaches more than 99%, and the tar content is lower than 0.1 mg/m ³ .

Example 3

Catalyst used is identical with embodiment 1.

The catalytic reformer used and the preparation method are basically the same, the difference is that the molar ratio of the crude gas to _O2 added is 100:5, and the amount of water vapor is 1.2kg/ ^m3 ; the high-temperature crude gas is in the reforming reactor Under the action of the catalyst, the reaction temperature is 780°C.

Under the above conditions, the catalytic reforming reaction system has been continuously operated for 300 hours, and the catalyst has not been detected to be deactivated by carbon deposition. The analysis of the composition of the synthesis gas after the reforming reaction shows that the H ₂ /CO ratio is 1.3, and the CH4 content in the synthesis gas is reduced. When it is lower than 0.1 mol%, the conversion rate of tar in the raw biomass gas reaches more than 99%, and the tar content is lower than 0.1 mg/m ³ .

Claims (7)

1. A method for preparing synthesis gas from raw biomass fuel gas, is characterized in that, comprises the steps: (1) The high-temperature crude gas obtained by gasifying biomass is subjected to cyclone separation to remove most of the coke particles; (2) Send into the reforming reactor again; Add superheated steam and oxygen in the reforming reactor simultaneously, wherein, the crude gas added and _O The molar ratio is 100: 2～6, in every cubic meter of crude gas The amount of water vapor added is 0.12-1.20kg; under the action of the catalyst in the reforming reactor, the high-temperature crude gas is subjected to catalytic reforming in the presence of oxygen at a reaction temperature of 640-850°C, and is directional converted into a gas mainly containing H ₂ and CO , and CO The synthesis gas of the _component ; The catalyst is a highly stable nickel-magnesium solid solution catalyst; (3) The reformed synthesis gas enters the synthesis system after being cooled and dedusted. 2. The method for preparing synthesis gas from raw biomass gas according to claim 1, further comprising the step of reducing and activating the reforming catalyst at a temperature of 700-850° C. 1 to 3 hours. 3. the method for preparing synthesis gas from biomass crude gas according to claim 1, is characterized in that, the crude gas added in step (2) and O The mol ratio is 100: ₃ , in every cubic meter of crude gas The amount of water vapor added is 0.8-1.20kg; the reaction temperature is 700-800°C. 4. The method for preparing synthesis gas from biomass crude gas according to any one of claims 1-3, characterized in that: the high-stable nickel-magnesium solid solution catalyst is prepared by the following method: (1) Dissolving Ni(AC) ₂ and Mg(NO3) ₂ crystals in distilled water to form a solution a having a molar ratio of Ni and Mg atoms of 2:100 to 5:100; (2) First heat the mixed solution a to 57-62°C, then titrate with an equal volume of 2mol/L K ₂ CO ₃ solution in a beaker under stirring, while keeping the constant temperature of the solution at 57°C, and the titration speed during titration is 10 -15ml/min, the pH value is always kept between 8-10; (3) After standing still for 1.5-2.5 hours, suction filter, and quickly rinse with hot water at 60°C, and then rinse with a large amount of 0.1mol/l (NH ₄ )HCO ₃ solution to remove K ⁺ ; (4) Dry at 120°C for 12 hours, then calcinate and co-melt at 950°C for 20 hours, and finally extrude. 5. a reforming reactor used in the method for preparing synthesis gas from biomass crude gas described in claim 1, characterized in that: in the reactor, upper dividing plate (21), lower dividing plate (22) are provided and The space in the reactor is divided into an exhaust chamber (20), a flue gas chamber (9), and an ash chamber (8) from top to bottom, and at least two reaction tubes (10) are arranged in the flue gas chamber (9). ), the two ends of the reaction tube (10) run through the upper partition (21), the lower partition (22) respectively; the lower port position of the reaction tube (10) is provided with a filter screen (12) and the reaction tube (10) ) is separated from the ash collection chamber (8); the wall of the reactor is provided with an air supply port, a crude gas inlet (14), a flue gas inlet (13), a flue gas outlet (15), and a reformed gas outlet (16); the ash collection chamber (8) top communicates with the outside world respectively through the air supply port and the crude gas inlet (14), and the flue gas chamber (9) bottom and the flue gas chamber (9) top respectively pass through the flue gas inlet (13), The flue gas outlets (15) communicate with the outside respectively, and the exhaust chamber (20) communicates with the outside through the reformed gas outlet (16). 6 . The reforming reactor according to claim 5 , characterized in that, the gas supply port includes an oxygen inlet ( G3 ) and a water vapor inlet ( G4 ). 7. The reforming reactor according to claim 5, characterized in that, the bottom of the reactor is provided with an ash outlet (11), and the ash collection chamber (8) is connected with the ash outlet (11) Communicate with the outside world.

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