CN101880552B - Gasification device and method for preparing hydrogen-rich synthetic gas from biomass - Google Patents

Abstract

The invention provides a biomass gasification device and method for preparing hydrogen-rich synthesis gas. The device includes a biomass feeder, a mixer, a pyrolysis chamber, a gasification chamber, a gasification gas separator, a combustion chamber, a flue gas separator, a feed bin, and a disc valve. The method of the invention divides the biomass gasification process into three parts: biomass pyrolysis, semi-coke gasification and heat carrier circulation. The invention can obtain the synthesis gas with the tar content lower than 200 mg/Nm ³ and the H ₂ /CO ratio higher than 1.1, and the energy utilization rate and process economical efficiency are significantly improved.

Description

A gasification device and method for preparing hydrogen-rich synthesis gas from biomass

technical field

The invention relates to the technical field of biomass gasification, in particular to a gasification device and method for producing hydrogen-rich synthesis gas from biomass. the

technical background

The physical and chemical processes of biomass gasification mainly include biomass drying, pyrolysis, gasification, and gas phase reaction. The above pyrolysis and gasification processes can produce tar. When the pyrolysis reaction temperature is 400°C, the biomass devolatilizes to produce sugars, aldehydes, and acid compounds. Butene and cyclopentadiene are the main precursors of tar; as the reaction temperature rises, these precursors undergo devolatization H. Polymerization and other reactions to generate phenolic compounds; when the reaction temperature is further increased to 900°C, the tar is mainly composed of polycyclic aromatic hydrocarbons and alkyl-substituted polycyclic aromatic hydrocarbons. According to the characteristics of tar components changing with temperature, Milne and Evans divided biomass tar into three categories: primary tar represented by sugars and aldehydes; secondary tar represented by phenols. tar); the third type of tar (tertiary tar) represented by polycyclic aromatic hydrocarbons and alkyl-substituted polycyclic aromatic hydrocarbons. the

Studies have shown that the gas tar content of the crude product obtained by updraft fixed bed, fluidized bed and downdraft fixed bed gasification is roughly 100g/Nm ³ , 10g/Nm ³ , 1g/Nm ³ . Different types of reactors are related to the main components of tar. Updraft gasification mainly produces the first type of tar, while downdraft gasification produces the main component of the third type of tar. The tar obtained by fluidized bed gasification is The second and third types of tar are mainly used.

The hazards of excessive tar content in crude product gas can be summarized as follows: 1) increasing the difficulty and complexity of gas purification treatment; 2) light tar such as phenol dissolved in washing water can pollute water bodies, such as naphthalene can form crystallization to block valves and power generation equipment , The condensation of heavy tar below 350°C can block the intercooler of the internal combustion engine; 3) the acidic substances contained in the tar can corrode the cylinder of the internal combustion engine or gas turbine; 4) reduce the gasification efficiency and energy utilization efficiency of the system. the

Therefore, the biomass gasification gas must be purified before it can be used. The tar removal technology can be divided into removal in the furnace (such as oxidative cracking, thermal cracking, catalytic cracking in the furnace) and removal outside the furnace (such as catalytic cracking outside the furnace, bag filter, wet Washing, electrostatic capture) two ways. The more typical processes can be divided into the following three types: 1) gasification + dolomite guard bed + Ni-based main bed catalysis; 2) high temperature thermal cracking; 3) charcoal catalytic cracking. Based on the fact that the catalytic activity of Ni-based catalysts drops sharply when dealing with crude product gas with a tar content of 2g/Nm ³ , the University of Zaragoza, Spain, proposed a process combining in-furnace and out-of-furnace removal: before the main bed of Ni-based catalysts Increase the three-step gasification of the dolomite guard bed, which can not only avoid the deactivation of the Ni-based catalyst too quickly, but also obtain a relatively clean syngas with a tar content of less than 200mg/Nm ³ . The second process is proposed by Thailand Asia Institute of Technology, through the introduction of secondary air into the reduction zone of the gasifier to generate high temperature to thermally crack tar, so as to achieve the purpose of reducing tar. The third is the fixed-bed pyrolysis-gasification two-stage gasifier proposed by the Technical University of Denmark, which makes the ungasified semi-coke of biomass form a charcoal bed at the outlet of the gasifier, and uses the reduction effect of the high-temperature charcoal bed to catalyze Pyrolysis tar, the latter two processes belong to a multi-stage gasification. By performing pyrolysis and gasification reactions in different reactors or different areas of the same reactor during the gasification process, the reaction conditions can be optimized and controlled in different reaction areas, so that Each conversion process and operating conditions are optimized to reduce tar content, thereby improving gasification efficiency and gas quality.

The above three processes have obvious weaknesses. The pyrolysis process needs to burn part of the combustible gas to make the reactor reach a high temperature of 1000 ° C, thereby sacrificing the calorific value of the gasification gas; the two-stage gasification process requires a large number of heat sources to supply heat to the pyrolysis chamber. solution, and the fixed bed has the disadvantage of being difficult to scale up; although the three-step process can obtain a gas with a high degree of cleanliness, the cost is too high and the economy is poor. the

So far, gasification technology has been widely used in other occasions including power generation, such as biomass-based liquid fuel technology, biomass-based fuel cell technology, etc. These technologies put forward higher requirements on the composition of gasification gas, such as traditional air The H ₂ /CO ratio of the synthesis gas produced by the gasification technology is only between 0.25-0.50, and even if O ₂ -steam gasification is used, it can only reach 0.60-0.87. When methyl ether is used, the H ₂ /CO ratio of the raw gas is required to be maintained between 1.1-2.0; at the same time, in order to reduce the operating cost of the downstream tar removal process, the tar content in the crude product gas is maintained at 200mg/Nm ³ The following is one of the reliable measures to improve the economics of gasification technology, so it is necessary to find other new processes with high feasibility and wide application.

Contents of the invention

In order to overcome the shortcomings of the existing biomass gasification technology, the present invention provides a gasification device and method for preparing low-tar hydrogen-rich synthesis gas from biomass. the

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

The gasification device of the present invention is a biomass circulating fluidized bed gasification device, which includes: a biomass feeder, a mixer, a pyrolysis chamber, a gasification chamber, a gasification gas separator, a return pipe, and an auxiliary fuel Feeder, combustion chamber, flue gas separator, silo, butterfly valve. According to the biomass feed and solid particle circulation path, the positions and connection methods of these components are as follows: the biomass feeder is connected to the mixer through the feed pipe, the upper end of the mixer is connected to the disc valve, the lower end is connected to the pyrolysis chamber, and the outlet of the pyrolysis chamber is set gradually. The conical tube is shrunk, most of the cones are inserted into the right side of the gasification chamber, the beginning of the cone and the end of the cone are respectively provided with air/O ₂ and water vapor inlets, and the gasification chamber is separated by a middle partition to become connected at the bottom On the left and right sides, the bottoms of the left and right sides of the gasification chamber are equipped with air/ _O2 inlets, and the bottom of the right side of the gasification chamber is also equipped with a slag discharge port. The middle and upper part on the left side of the gasification chamber is connected to the lower part of the combustion chamber through the return pipe. The lower part of the gasification gas separator is equipped with a solid particle silo, and a stop valve is installed on the lower part of the silo to connect with the bottom of the combustion chamber to intermittently return the material to the combustion chamber. An auxiliary fuel feeding port and a primary air inlet are arranged at the bottom of the combustion chamber, and a secondary air inlet is arranged at the middle and upper part of the combustion chamber. The outlet on the top of the combustion chamber is connected to the flue gas separator, the upper part of the flue gas separator is provided with a flue gas discharge port, the lower part of the flue gas separator is provided with a silo, and the lower part of the silo is connected to a butterfly valve.

The disc valve communicates with the mixer through the outlet tube of the disc valve. The outlet tube is inserted into the cavity of the mixer. The length of the inserted part is 1-1.5 times the inner diameter of the outlet tube, and it is in an inward contracting shape, which can guide solid heat. Carrier role. the

The mixer is composed of an upper cylindrical cavity and a lower conical cavity, the height ratio of the two is 3-4:1, the upper end of the cavity is connected to the outlet pipe of the disc valve, and the lower end is connected to the outlet pipe of the disc valve. The pyrolysis chambers are connected, and an arc-shaped conical particle diversion cone is installed on the axis line. The diversion cone is supported by a support tube. A feeding pipe is set between the outlet pipe of the disc valve and the diversion cone. The radian of the arc surface is 45-60°, and the direction of the feeding pipe and the axis of the mixer is at an angle of 15-30°. The projection of the outlet port of the feeding pipe must be located on the diversion cone and must be close to the side of the axis of the mixer. . The outlet end of the feeding pipe is closer to the end of the outlet pipe of the disc valve in the axial direction, and farther away from the diversion cone arc surface. the

The pyrolysis chamber is a cylindrical cylinder, and the pyrolysis chamber is alternately arranged on both sides of the axis line with semi-elliptical baffles at an angle of 45-60° to the axis line and inclined upwards. The baffles are elliptical The center is fixed on the baffle bracket. The upper edge of the baffle is close to the inner wall of the pyrolysis chamber cylinder but does not touch it. The position of the baffle bracket coincides with the axis of the pyrolysis chamber. Size, the distance between each baffle is 0.3-0.6m, and the number of baffles is 5-10. The outlet of the pyrolysis chamber transitions from an inverted tapered necking cone to a cylindrical cylinder with a slightly smaller diameter. The cylindrical cylinder is inserted into the right side of the gasification chamber, and the insertion length is about 1/3 of the height of the right side of the gasification chamber. Between -1/2, 4 air/O ₂ inlets are set on the section at the upper edge of the cone, and 4 water vapor inlets are set on the section at the lower edge of the small-diameter cylindrical cylinder. The air/O ₂ The introduction port and the water vapor introduction port are symmetrically distributed at the four quadrant points of the cross section respectively.

The gasification chamber is a rectangular parallelepiped bubbling reactor whose bottom is connected and the upper part is separated by the partition plate of the gasification chamber, namely the left side and the right side of the gasification chamber. The partition is located in the middle of the cuboid gasification chamber, and the height of the partition is 2/3-4/5 of the height on the right side of the gasification chamber. The gasification chamber on the right is connected to the outlet of the pyrolysis chamber, and a slag discharge port and 4 air/O ₂ inlets are set at the bottom of the gasification chamber on the right. The top of the left gasification chamber is connected to the gasification gas separator, and the left side of the left gasification chamber is about 4/5 of the height of the gasification chamber. There is also an air/O ₂ inlet at the bottom of the gasification chamber, and the gasification agent in this inlet also functions as fluidizing air.

The bottom of the gasification gas separator is connected with a shut-off valve, the shut-off valve is connected with the outlet pipe and connected with the bottom of the combustion chamber, and the top of the gasification gas separator is provided with a synthesis gas outlet. the

An auxiliary fuel feeding port and a primary air inlet are arranged at the bottom of the combustion chamber, and a secondary air inlet is arranged at about 1/2-2/3 height of the middle and upper part of the combustion chamber. The outlet at the top of the combustion chamber is connected to the flue gas separator. the

The method for preparing low-tar, hydrogen-rich synthesis gas from biomass in the present invention is a circulating fluidized bed gasification process, and its process scheme is as follows: the traditional CFB biomass gasification process is divided into biomass pyrolysis, semi-coke gasification, thermal The carrier loop has three parts. After the biomass and the adsorbent are mixed, they are fed by the biomass feeder, run to the mixer through the feeding pipe, and are mixed with the circulating heat carrier and fly ash at the mixer, and then the heat is transferred rapidly; the biomass, heat carrier and adsorbent The solid particles are accelerated into the pyrolysis chamber under the action of gravity, and the biomass, heat carrier and adsorbent are mixed evenly in the pyrolysis reaction chamber, and at the same time, the catalytic pyrolysis reaction of biomass is carried out to fully analyze the volatile matter; in the outlet section of the pyrolysis chamber Air or _O2 is introduced at the upper edge of the cone, and water vapor is introduced at the outlet of the pyrolysis chamber to pre-gasify the semi-coke obtained from biomass pyrolysis; Enter air or _O2 to gasify the semi-coke for the second time, and discharge the slag irregularly through the slag discharge port on the right side of the gasification chamber; discharge the gasification gas from the top left side of the gasification chamber, and then separate and purify it by the gasification gas separator for later use , ungasified semi-coke, circulating heat carrier, and adsorbent particles move to the bottom of the combustion chamber through the return pipe; add auxiliary fuel at the bottom of the combustion chamber, and introduce primary air to oxidize the semi-coke and auxiliary fuel, and the resulting high temperature can be heated Circulating heat carrier and calcining regenerated adsorbent, the secondary air can further burn out residual charcoal, and the combustion flue gas is discharged after passing through the cyclone separator; the heat carrier, regenerated adsorbent, and fly ash carry the combustion chamber to absorb heat and pass through the silo , The butterfly valve participates in the next cycle and provides heat for the pyrolysis reaction, and the tail gas is combustion flue gas rich in CO ₂ .

The function of the baffle structure set in the pyrolysis chamber is that solid particles such as biomass, heat carrier and adsorbent accelerate into the pyrolysis chamber under the action of gravity, and then are decelerated to a stationary state by the blocking of the pyrolysis chamber baffle. Then it slides down on the inclined pyrolysis chamber baffle, and is accelerated again under the action of gravity during the sliding process, undergoing repeated acceleration-deceleration cycles to increase the residence time of the above-mentioned solid particles in the pyrolysis chamber. the

The primary air and secondary air can be introduced before the gasification reaction starts, and the auxiliary fuel is put into the combustion chamber, and the mixture of heat carrier and adsorbent is put in after about 0.5-1 hour. The total mass of the heat carrier and adsorbent depends on the combustion Depending on the fluidization capacity of the chamber and the amount of biomass fed, the cycle rate can usually be maintained between 10-25. Irregular slagging at the slagging outlet will reduce the total mass of the heat carrier and adsorbent in the furnace, so the adsorbent should be replenished continuously when biomass is fed. Adsorbent particles used for catalytic cracking of tar and carbon fixation can be mixed with biomass and fed, or can be fed by an independent feeder. the

The adsorbent undergoes catalytic cracking-carbon fixation-calcination sequential reaction along with the solid particle circulation: 1) Catalyzes the pyrolysis of biomass in the pyrolysis chamber; 2) Participates in the catalytic cracking tar reaction and carbon fixation reaction in the gasification chamber; 3 ) after returning to the combustion chamber, a high-temperature calcination reaction occurs, and CO ₂ is released while restoring the porous surface.

The gas and solid flow structure in the outlet section of the pyrolysis chamber is a moving bed that moves slowly downward, and the semi-coke is pre-gasified during the downward movement, and the moving speed of solid particles depends on the gasification agent introduced at the bottom of the gasification chamber Gas flow rate; the gas and solid flow structure of the gasification chamber is a dense-phase bubbling bed. The pyrolysis gas containing tar and its precursors passes through the moving bed-bubbling bed structure composed of semi-coke, adsorbent, and heat carrier, and the semi-coke undergoes a secondary gasification reaction under the action of the gasification agent; the tar component is heated Semi-coke, adsorbent active components, fly ash, etc. are catalytically cracked into small molecular gases; the adsorbent absorbs the CO ₂ generated during the gasification process, and because the partial pressure of CO ₂ in the reactor is reduced, the water-gas shift reaction can be promoted to The generated H ₂ moves in the direction, so that the gasification gas with high H ₂ content and low tar content can be obtained.

The adsorbent can be one of limestone, dolomite or olivine, and the gasification agent can be one or two of air, O ₂ and water vapor. The heat carrier can be quartz sand or river sand, the mass ratio of the adsorbent to the heat carrier is about 30%, and the adsorbent is fed continuously, accounting for 3-10% of the total feed amount.

The equivalence ratio of the gasification reaction is 0.20-0.35, and the amount of water vapor introduced is maintained at 0.3-1.0 of water vapor/biomass. the

The pyrolysis reactor temperature is 400-900°C, preferably 500-750°C, the residence time is greater than 1s, the gasification reactor reaction temperature is 600-1000°C, preferably 700-850°C, and the combustion chamber reaction temperature is 800-1200°C, preferably 850-1000°C. the

The present invention can obtain synthesis gas with tar content lower than 200mg/Nm ³ and H ₂ /CO ratio greater than 1.1, and its characteristics are:

1. After the biomass/adsorbent is fed, it is quickly mixed with the heat carrier, fly ash, etc. at the mixer, and the temperature rises rapidly to rapidly pyrolyze;

2. Set baffles in the pyrolysis chamber to increase solid back-mixing to facilitate further pyrolysis;

3. The outlet of the pyrolysis chamber, that is, the inlet of the gasification chamber, is in the form of a constriction, and air/ _O2 and water vapor are respectively introduced into the reactor volume reduction and expansion, making full use of the characteristics of the gasification reaction, which is conducive to the oxygen-enriched oxidation of biomass The reversible reaction of reaction and water vaporization moves to the direction of forward reaction;

4. The active components of the adsorbent capture CO ₂ in the gasification chamber to promote the steam reforming reaction to obtain hydrogen-rich gas;

5. Unreacted semi-coke and auxiliary fuel are burned in the combustion chamber to heat the heat carrier, and the adsorbent is calcined to obtain active components and restore the porous active surface;

6. Adsorbent can catalyze biomass pyrolysis reaction; semi-coke and adsorbent can catalyze tar cracking reaction. the

Compared with the prior art, the present invention realizes step-by-step control of the gasification reaction process in different regions of the CFB for biomass pyrolysis, coke/adsorbent catalytic cracking tar, coke gasification, tar pyrolysis, and fuel combustion, and has the following advantages :

1) The biomass pyrolysis and gasification processes are relatively separated to achieve optimal control of different processes: the biomass pyrolysis process heats up rapidly, which can effectively avoid the aggregation and growth of tar molecules during the pyrolysis process, and can be realized by controlling the pyrolysis conditions Directional escape of tar; according to the stage characteristics of the gasification process, the pyrolysis semi-coke of biomass itself is used to suppress the production of tar, and realize the catalytic conversion and thermal cracking of tar semi-coke and the directional control of gas components;

2) The heat required for biomass pyrolysis is provided by the circulating heat carrier, and the optimization of heat transfer and mass transfer conditions in the pyrolysis chamber and gasification chamber can achieve uniform temperature distribution and significantly improve the energy utilization rate of the system;

3) The adsorbent can not only play the role of heat carrier in the whole process, but also effectively promote the biomass gasification reaction: through the carbon fixation reaction of the active component of the adsorbent in the gasification chamber, the concentration of CO ₂ in the gas phase can be reduced, and the water-gas shift reaction can be effectively promoted to obtain Hydrogen-rich synthesis gas; promotes the water vapor gasification reaction through the carbon fixation reaction of the active components of the adsorbent and the exothermic effect of the water-gas shift reaction. The obtained gasification gas H ₂ /CO is greater than 1.1, and the adsorbent is regenerated through the calcination reaction in the combustion chamber, and the active porous surface is restored, and the tail gas is rich in CO ₂ and is easy to capture;

4) The use of cheap and easy-to-obtain adsorbents avoids complicated downstream tar removal equipment and processes, without sacrificing the calorific value of the gas, and does not require conditioning of the H ₂ /CO molar ratio of the gasification gas, which improves the biomass gasification process economy.

Description of drawings

Fig. 1 is a general diagram of a circulating fluidized bed gasification device according to an embodiment of the present invention. the

Fig. 2 is a schematic diagram of the internal structure of the mixer according to the embodiment of the present invention. the

Fig. 3 is a schematic diagram of the internal structure of the pyrolysis chamber according to the embodiment of the present invention. the

Fig. 4 is a schematic diagram of the internal structure of the gasification chamber and the structure of the air distribution and slag discharge outlets according to the embodiment of the present invention. the

Description of reference signs: 1-biomass feeder, 2-mixer, 3-pyrolysis chamber, 4-gasification chamber, 5-gasification gas separator, 6-return pipe, 7-distribution plate, 8- Combustion chamber, 9-flue gas separator, 10-silo, 11-disc valve, 12-disc valve outlet pipe, 13-biomass feeding pipe, 14- diversion cone, 15- diversion cone support column, 16- Pyrolysis chamber baffle, 17-baffle bracket, 18-gasification chamber partition. the

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. the

As shown in Figure 1, the device structure of the present invention is: the biomass feeder 1 is connected to the mixer 2 through the biomass feed pipe 13, the upper end of the mixer 2 is connected to the disc valve 11, the lower end is connected to the pyrolysis chamber 3, and the outlet of the pyrolysis chamber 3 A tapered conical tube is set, most of the cones are inserted into the right side of the gasification chamber 4, air/ _O2 and water vapor inlets are installed at the beginning of the cone and at the end of the cone respectively, and the gasification chamber 4 passes through the middle partition Isolate the left and right sides connected at the bottom, the bottoms of the left and right sides of the gasification chamber 4 are provided with air/ _O2 inlets, the bottom of the right side of the gasification chamber 4 is also provided with a slag discharge port, and the top of the left side of the gasification chamber 4 leads to a pipe connecting the gas The upper side of the gasification separator 5, the middle and lower part on the left side of the gasification chamber 4 is connected to the lower part of the combustion chamber 8 through the return pipe 6, the lower part of the gasification gas separator 5 is provided with a solid particle silo, and a shut-off valve is installed at the lower part of the silo It is connected to the bottom of the combustion chamber to intermittently feed back to the combustion chamber 8. The bottom of the combustion chamber 8 is provided with an auxiliary fuel feeding port and a primary air inlet, and the middle and upper part of the combustion chamber 8 is provided with a secondary air inlet. The outlet on the top of the combustion chamber 8 is connected to the flue gas separator 9 , the upper part of the flue gas separator 9 is provided with a flue gas discharge port, the lower part of the flue gas separator 9 is provided with a silo 10 , and the lower part of the silo 10 is connected to a disc valve 11 .

The disc valve 11 communicates with the mixer 2 through the disc valve outlet pipe 12, the outlet pipe is inserted into the cavity of the mixer 2, the length of the inserted part is 1-1.5 times the inner diameter of the outlet pipe, and it is inwardly contracted, which can play a role The role of conduction solid heat carrier. the

As shown in Figure 2, the mixer 2 is composed of an upper cylindrical cavity and a lower conical cavity. Pipe 12 is connected, and the lower end is connected with pyrolysis chamber 3, and arc-shaped conical surface particle diversion cone 14 is installed on the axis line, and diversion cone 14 is supported by diversion cone support column 15, and the arc surface of this arc-shaped cone surface The arc is 45-60°, and the biomass feeding pipe 13 is set between the disc valve outlet pipe 12 and the diversion cone 14. The biomass feeding pipe 13 is at an angle of 15-30° with the axis of the mixer 2, and the biomass The projection of the outlet port of the feed pipe 13 should all be located on the diversion cone 14 and be close to the side of the axis of the mixer 2 . The outlet end of the biomass feeding pipe 13 is closer to the pipe end of the disc valve outlet pipe 12 in the axial direction, and farther away from the arc surface of the diversion cone 14 . the

As shown in Figure 3, the pyrolysis chamber 3 is a cylindrical shell, and the pyrolysis chamber 3 is alternately arranged on both sides of the axis line to form a semi-elliptical shape with an angle of 45-60° with the axis line and inclined upward. Baffle plate 16, the elliptical center of the baffle plate 16 is fixed on the baffle plate bracket 17, the upper edge of the baffle plate 16 is close to the inner wall of the pyrolysis chamber cylinder but does not touch, and the position of the baffle plate bracket 17 is in line with the axis of the pyrolysis chamber Coincidentally, according to the inner diameter of the pyrolysis chamber 3 and the particle size of the biomass particles, the distance between each baffle is 0.3-0.6m, and the number of baffles is 5-10. The outlet of the pyrolysis chamber 3 transitions from an inverted tapered necking cone to a cylindrical cylinder with a slightly smaller diameter. The cylindrical cylinder is inserted into the right side of the gasification chamber 4, and the insertion length is about 1 of the height of the right side of the gasification chamber. /3-1/2 between. As shown in Figure 4, _four air/ _O2 inlets are provided on the section at the upper edge of the cone, and four water vapor inlets are arranged on the section at the lower edge of the small-diameter cylindrical cylinder. The inlet and the water vapor inlet are symmetrically distributed at the four quadrant points of the cross-section respectively.

The gasification chamber 4 is a rectangular parallelepiped bubbling reactor whose bottom is connected and the upper part is separated by a partition of the gasification chamber, that is, two parts on the left side and the right side of the gasification chamber. The partition is located in the middle of the cuboid gasification chamber 4, and the height of the partition is 2/3-4/5 of the height on the right side of the gasification chamber. The gasification chamber on the right is connected to the outlet of the pyrolysis chamber, and a slag discharge port and an air/O ₂ inlet are arranged at the bottom of the right gasification chamber. The top of the left gasification chamber is connected to the gasification gas separator, and the left side of the left gasification chamber is provided with a solid particle outlet at about 4/5 of the height of the gasification chamber, which communicates with the bottom of the combustion chamber 8 through the return pipe 6, There is also an air/O ₂ inlet at the bottom of the gasification chamber on the left, and the gasification agent also functions as fluidizing air.

The bottom of the gasification gas separator 5 is connected with a shut-off valve, the shut-off valve is connected with the outlet pipe and connected with the bottom 8 of the combustion chamber, and the top of the gasification gas separator 5 is provided with a synthesis gas outlet. the

The bottom of the combustion chamber 8 is provided with an auxiliary fuel feeding port and a primary air inlet, and a secondary air inlet is provided at a height of about 1/2-2/3 of the middle and upper part of the combustion chamber 8 . The outlet at the top of the combustion chamber 8 is connected to the flue gas separator 9 . Example 1 A process for producing low-tar hydrogen-rich synthesis gas by circulating fluidized bed gasification of sawdust

Use the device shown in Figure 1 to get the sawdust raw material from the wood processing plant. The industrial analysis and elemental analysis of the sawdust are shown in attached table 1. The sawdust and adsorbent are mixed in a ratio of 95:5 and passed through the biomass feeder 1. The feeding pipe 13 is sent to the mixer 2, and the heat carrier and adsorbent at a temperature of 850°C are rapidly mixed and exchanged for heat exchange, and the cycle rate is changed by adjusting the opening of the disc valve 11 , the sawdust is heated to about 600°C, and then the sawdust, heat carrier, and adsorbent are accelerated into the pyrolysis chamber 3 by the action of gravity, and then decelerated to a stationary state by the blockage of the pyrolysis chamber baffle 16, experiencing continuous acceleration-deceleration The circulation process increases the residence time of wood chips in the pyrolysis chamber 3 to fully analyze the volatile matter. After the pyrolysis is completed, the semi-coke and volatile matter obtained together with the heat carrier and adsorbent move to the outlet of the pyrolysis chamber 3. At this time, O ₂ is introduced into the inlet of the gasification agent, and the inverted tapered neck structure here is reduced. Reaction volume, which can promote volume reduction reactions such as gasification reactions between C and O ₂ , CO and O ₂ , water vapor is introduced into the gasification agent inlet at the outlet of the necking section, the amount of O ₂ introduced is controlled at an equivalent ratio of 0.15, and water The steam/biomass mass ratio was 0.4.

The adsorbent is selected from one of limestone, dolomite or olivine, the gasification agent is selected from one or two of air, O ₂ , and water vapor, and the heat carrier is quartz sand or river sand; adsorption The mass ratio of the agent to the heat carrier is about 30%, and the adsorbent is fed continuously, accounting for 3-10% of the total feeding amount.

The ratio of 4:6 or 5:5 is introduced into the _{bottom of the left and right sides of the gasification chamber 4 respectively, and the total amount of O 2 introduced} in the two places is controlled to have an equivalent ratio of 0.11. The adsorbent and semi-coke continue to catalyze the cracking of tar here, while the adsorbent adsorbs CO ₂ and the semi-coke oxygen-enriched-water vapor gasification reaction occurs. The gasification reaction temperature is 750°C, and the gas phase product is drawn from the left top of the gasification chamber 4 and separated by the gasification gas separator 5 before being used. Solid phase particles such as adsorbent, heat carrier, fly ash, and unreacted semi-coke run to the bottom of the combustion chamber 8 through the return pipe 6 .

The auxiliary fuel is fed to the bottom of the combustion chamber 8 and burned together with the unreacted semi-coke that circulates here, the heat released is used to heat the circulating heat carrier and the adsorbent, and the adsorbent is calcined at high temperature to release _CO2 while restoring the porous catalytic surface , the auxiliary fuel can be coal or biomass, the amount of feed depends on the furnace temperature, and the temperature in the dense phase zone of the combustion chamber is kept at 900 °C. The upper part of the combustion chamber 8 is fed with secondary air to further burn off the residual charcoal. After the combustion flue gas is separated by the flue gas separator 9, the heat carrier and the regenerated adsorbent are obtained to continue to participate in the next round of circulation, while the flue gas rich in CO ₂ The gas is discharged through the exhaust chimney. The flue gas can be used to dry the biomass fuel, so that the moisture content of the biomass before feeding is about 10%.

In this embodiment, the main components of the obtained gasification gas are hydrogen, methane, carbon monoxide, carbon dioxide, ethane, ethylene, acetylene, propane, propylene, propyne and the like. After analysis, the main composition and physical properties of the gasification gas are shown in Table 2. At the same time, Table 2 also shows the composition and physical properties of the gasification gas obtained by a certain gasification method. The H ₂ content in the synthesis gas obtained by the gasification is 44.5%, which is 86.19% higher than the traditional gasification; the tar content is 0.189g/Nm ³ , which is 88.14% lower than the traditional gasification; the H ₂ /CO ratio is 1.36, It can be used as raw material gas for biomass-based liquid fuel process.

Table 1 Industrial analysis and elemental analysis of sawdust

Table 2 Comparison of gasification results between this embodiment and traditional gasification methods

Claims (12)

1. gasification installation by the standby hydrogen-rich synthetic gas of biomass-making, it is characterized in that: this device comprises following assembly: biomass feeder, mixing tank, pyrolysis chamber, vaporizer, gasification gas separating device, combustion chamber, smoke separator, feed bin, dish valve; The biomass feeder is connected with mixing tank by filling tube, and the mixing tank upper end connects the dish valve, and the lower end is communicated with the pyrolysis chamber, and pyrolysis chamber's outlet arranges the convergent conical tube, and most of cone is inserted the vaporizer right side, and cone section start and cone end arrange respectively air/O ₂With the water vapour intake, vaporizer becomes the left and right sides that the bottom is communicated with through the central dividing plate isolation, and bottom, the vaporizer left and right sides all arranges air/O ₂Intake, bottom, vaporizer right side also arranges slag-drip opening, vaporizer left side top introduction pipe connects the upside of gasification gas separating device, middle and upper part, vaporizer left side is connected with the bottom, combustion chamber by revert pipe, gasification gas separating device bottom arranges the solid particulate feed bin, and in the feed bin bottom stopping valve is installed and bottom the combustion chamber, is connected with the returning charge at intermittence to the combustion chamber, the bottom, combustion chamber arranges auxiliary fuel charging opening and primary air intake, the middle and upper part, combustion chamber arranges the secondary air intake, the top of combustion chamber outlet connects smoke separator, smoke separator top arranges the fume emission mouth, and the smoke separator bottom arranges feed bin, and the feed bin bottom connects the dish valve.

2. as claimed in claim 1 by the gasification installation of biomass-making for hydrogen-rich synthetic gas, it is characterized in that: described dish valve is communicated with mixing tank by dish valve outlet port pipe, this outlet pipe inserts the mixing tank cavity, and insertion portion length is 1-1.5 times of the outlet pipe internal diameter, and is inside collapsed shape.

3. as claimed in claim 1 or 2 by the gasification installation of biomass-making for hydrogen-rich synthetic gas, it is characterized in that: described mixing tank is comprised of coaxial top cylinder barrel shaped cavity and lower cone shape cavity, the ratio of both height is 3-4:1, at the cavity axial line arc conical surface particle deflection cone is installed, deflection cone supports by supporting tube, between the dish valve outlet port pipe that is communicated with the mixing tank upper chamber and deflection cone filling tube is set.

4. as claimed in claim 3 by the gasification installation of biomass-making for hydrogen-rich synthetic gas, it is characterized in that: the cambered surface radian of the described deflection cone arc conical surface is 45-60 °, filling tube and mixer chamber body direction of axis line are 15-30 ° of angle, and the projection of filling tube outlet port will all be positioned on the deflection cone and close mixer chamber body axial line one side of palpus.

5. as claimed in claim 1 by the gasification installation of biomass-making for hydrogen-rich synthetic gas, it is characterized in that: described pyrolysis chamber is cylindrical tube, the pyrolysis chamber is arranged alternately the half elliptic baffle plate that is 45-60 ° of angle and tilts upward with axial line along about cylindrical shell axial line both sides, described baffle plate elliptical center place is fixed on the barrier support, the baffle plate upper limb is near pyrolysis chamber's right cylinder inwall but do not come in contact, the barrier support placement location overlaps with pyrolysis chamber's cylindrical shell axial line, the exit, pyrolysis chamber is transitioned into the slightly little cylindrical tube of diameter by back taper reducing cone, and the cylindrical tube that described diameter is slightly little inserts the vaporizer right side.

6. as claimed in claim 1 by the gasification installation of biomass-making for hydrogen-rich synthetic gas, it is characterized in that: described vaporizer is the cuboid bubbling reactor that a bottom is communicated with, top is vaporized chamber dividing plate isolation, dividing plate is positioned at the middle of rectangular parallelepiped vaporizer, and the dividing plate height is the 2/3-4/5 of vaporizer right side height; The right side vaporizer links to each other with pyrolysis chamber's outlet, and vaporizer bottom in right side arranges 1 slag-drip opening and 4 air/O ₂Intake, vaporizer top, left side connect the gasification gas separating device, and vaporizer height 4/5 place, left side of left side vaporizer arranges the solid particulate outlet, are connected with the bottom, combustion chamber by revert pipe, and vaporizer bottom in left side also is provided with 1 air/O ₂Intake.

7. as claimed in claim 1 by the gasification installation of biomass-making for hydrogen-rich synthetic gas, it is characterized in that: described gasification gas separating device bottom connects stopping valve, bottom, stopping valve connection outlet Guan Bingyu combustion chamber connects, and gasification gas separating device top arranges syngas outlet.

8. as claimed in claim 1 by the gasification installation of biomass-making for hydrogen-rich synthetic gas, it is characterized in that: bottom, described combustion chamber arranges auxiliary fuel charging opening and primary air intake, and middle and upper part, combustion chamber 1/2-2/3 At The Height arranges the secondary air intake.

9. a right to use requires the method by the standby hydrogen-rich synthetic gas of biomass-making of 1 device, it is characterized in that: divide form biomass pyrolysis, char Gasification, thermal barrier three parts that circulate with biomass gasification process; Biomass are mixed with sorbent material by biomass feeder feed, move to mixing tank by filling tube, and the mixing tank place with carry out rapidly the heat transmission after thermal cyclic carrier, flying dust mix; Biomass, thermal barrier and adsorbent solids particle accelerate to enter the pyrolysis chamber under action of gravity; When mixing, biomass and thermal barrier, sorbent material carry out the catalytic pyrolysis of biomass reaction fully to separate out fugitive constituent in the pyrolysis chamber; Cone upper limb place's introducing air or O at pyrolysis chamber's outlet section ₂, pass into the semicoke that water vapour obtains with pre-gasified bio-matter pyrolysis in the exit, pyrolysis chamber; Vaporized chemical intake on vaporizer left side, right side passes into air or O respectively ₂With the semicoke second gasification, and irregularly discharge slag by the slag-drip opening on vaporizer right side; For subsequent use behind gasification gas separating device isolation of purified from vaporizer left side top discharge gasifying gas, the semicoke of gasification, thermal cyclic carrier, absorbent particles do not move to the bottom, combustion chamber through revert pipe; Add auxiliary fuel in the bottom, combustion chamber, and introduce primary air with semicoke, auxiliary fuel oxidation, the heat thermal cyclic carrier of generation and calcination and regeneration sorbent material, the further after-flame carbon residue of secondary air, combustion product gases discharges behind cyclonic separator; Sorbent material, flying dust after thermal barrier, the regeneration carries the combustion chamber absorbing heat and participates in the next round circulation and for pyrolytic reaction provides heat, tail gas is to be rich in CO through feed bin, dish valve ₂Combustion product gases.

10. as claimed in claim 9 by the method for biomass-making for hydrogen-rich synthetic gas, it is characterized in that: after biomass, thermal barrier and adsorbent solids particle accelerate to enter the pyrolysis chamber under action of gravity, through pyrolysis chamber's baffle plate stop and to be decelerated to convergence static, subsequently landing downwards on the pyrolysis chamber's baffle plate that tilts, again be accelerated under action of gravity in the process of landing, experience acceleration-deceleration working cycle repeatedly is to increase the residence time of above-mentioned solid particulate in the pyrolysis chamber.

11. the method by the standby hydrogen-rich synthetic gas of biomass-making as claimed in claim 9, it is characterized in that: before gasification reaction begins, namely pass into primary air and secondary air, and to combustion chamber input auxiliary fuel, throw in afterwards the mixture of thermal barrier and sorbent material, thermal barrier and sorbent material drop into total mass to be decided on combustion chamber fluidisation ability and biomass feeding quantity; Described slag-drip opening carries out irregular deslagging can make that thermal barrier and sorbent material total mass tail off in the stove, so biomass are answered the continuous supplementation sorbent material when reinforced; The absorbent particles that is used for catalytic cracking of tar and solid carbon mixes rear feeding with biomass, or adopts independently feeding machine charging.

12. by claim 9 or 11 described methods by the standby hydrogen-rich synthetic gas of biomass-making, it is characterized in that: described sorbent material is selected from Wingdale, rhombspar or the peridotites a kind of, described thermal barrier is quartz sand or river sand; The mass ratio 30% of sorbent material and thermal barrier, the sorbent material continuous-feeding accounts for the 3-10% of total feeding coal.

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