CN208151309U - A kind of fluidized bed pyrolysis device preparing high heating value biological fuel gas - Google Patents

Abstract

The utility model discloses a kind of fluidized bed pyrolysis devices for preparing high heating value biological fuel gas, including fluidized bed, cyclone separator, heat exchanger and feeder, feeder is for sending the biomass material after broken drying to fluidized bed, it is connected at the top of the entrance of cyclone separator and fluidized bed, the emulsion zone section in fluidized bed is arranged in heat exchanger, heat exchanger provides pyrolysis institute's calorific requirement by heat exchange for biomass material, it further include booster fan and biomass gas burner, the exhaust outlet of cyclone separator is connected with the air inlet of booster fan, the gas outlet of booster fan is connected with the air inlet of burner, the hot fume outlet of burner is connected with the thermal medium entrance of heat exchanger.Compared with prior art, the utility model meets thermal cracking institute calorific requirement in furnace using combustion gas itself is produced, and compared to the pyrolysis way using extra fuel and electric energy, reduces operating cost.

Description

A fluidized bed pyrolysis device for preparing high calorific value biomass gas

technical field

The utility model relates to a fluidized bed pyrolysis device for preparing high calorific value biomass gas.

Background technique

Biomass solid waste is rich in resources, vigorously developing the resource utilization of biomass solid waste will help to improve my country's energy structure dominated by fossil fuels, which can not only reduce the emission of sulfide and nitrogen oxides, but also relieve the effect. Biomass pyrolysis gasification technology realizes the transformation of low-grade biomass into high-quality gas, which can replace fossil energy such as coal and petroleum in many fields. Biomass gasification is a more efficient biomass energy utilization technology. The basic principle is that biomass is insufficiently oxidized with gasification agents (such as air, oxygen or water vapor) at relatively high temperatures (700-900°C). The reaction produces a flammable gas mainly composed of carbon monoxide, hydrogen and methane. Biomass gas can be used for power generation, heat supply, civil kitchen gas, hydrogen production, liquid fuel, etc. However, there are still some bottlenecks in biomass gasification technology. A prominent problem is reflected in: the gasification agent commonly used at present is air. Although the cost of gasification is low, the calorific value of the gas is low due to the high nitrogen content in the biomass gas. , when used as a fuel, the combustion temperature is not high, and the heat utilization efficiency is low; when used as a raw material such as industrial synthesis gas, the gas purity is not enough, and it is often necessary to consider a gas separation and purification device, and the equipment investment and operating costs are high. The problem of low value has greatly affected the extensive development of biomass gasification technology.

The composition and calorific value of biomass gas obtained by using other gasification agents are different, and the technical maturity and economic efficiency are also different. When enriched oxygen or pure oxygen is used as the gasification agent, the reaction temperature is high, the reaction speed is fast, the tar content is low, and the calorific value is high (up to 2500kCal/Nm3), but the cost of oxygen production is high and the economy is poor. When water vapor is used as the gasification agent, the gas quality is good, the hydrogen content is high, and the gas with a medium calorific value (4200kCal/Nm3) is produced, or when air and water vapor are used together as the gasification agent, the calorific value can also reach 2500kCal /Nm3 or more, but the system needs to be equipped with a steam generator and superheating equipment, and an external heat supply source is required. The system has poor independence, complex technology, and high operating costs. Hydrogen gasification is a process in which hydrogen reacts with carbon and water to generate a large amount of methane. The reaction conditions are harsh, and it needs to be carried out under the conditions of high temperature and high pressure and a hydrogen source. It can produce high calorific value gas with a calorific value of about 5800kCal/Nm3. At present, there are basically no actual cases.

Therefore, it is necessary to use the gasification agent and gasification heat source as the technical breakthrough point to solve the contradiction between reducing the preparation cost and improving the quality of biomass gas.

Utility model content

The purpose of the utility model is to overcome the shortcomings and deficiencies of the prior art, and provide a fluidized bed pyrolysis device for preparing high-calorific-value biomass gas, which uses the gas produced by the device itself as a heat source and gasification agent, and has high processing efficiency and process Simple, while taking into account economy and system operation reliability.

In order to achieve the above object, the technical scheme adopted by the utility model is as follows:

A fluidized bed pyrolysis device for preparing high calorific value biomass gas, including a fluidized bed, a cyclone separator, a heat exchanger and a feeder, and the feeder is used to send crushed and dried biomass materials to the fluidized bed Inside, the inlet of the cyclone separator is connected with the top of the fluidized bed, and the heat exchanger is arranged in the dense phase section in the fluidized bed, and the heat exchanger provides the heat required for pyrolysis of the biomass material through heat exchange, and also includes The booster fan and the biomass gas burner, the exhaust port of the cyclone separator is connected with the inlet port of the booster fan, the outlet port of the booster fan is connected with the inlet port of the burner, the hot flue gas of the burner The outlet is connected with the heat medium inlet of the heat exchanger.

The working principle of the utility model: the gas produced by the thermal cracking of the fluidized bed is used as the heat source of the system, and the high-temperature flue gas is generated after being burned by the burner, and then the high-temperature flue gas is sent to the heat exchanger in the furnace, and the biomass is converted into biomass through heat exchange The material provides the heat required for pyrolysis, that is, the system uses its own gas to meet the heat required for pyrolysis in the furnace. Compared with the pyrolysis method using external fuel and electric energy, the operating cost is reduced.

As an improvement of the utility model, the feeder is a screw feeder, and the feeding hopper of the screw feeder is provided with a feeder with a large inclination angle, and the feeder with a large inclination angle is used to crush and dry the biomass The material is sent to the feed hopper of the screw feeder.

As an improvement of the utility model, a screw feeder is provided below the ash discharge port of the cyclone separator, and the screw feeder is used to send the ash to the feeding hopper of the screw feeder.

Further, a star discharge valve is provided at the ash outlet of the cyclone separator.

As an improvement of the utility model, the hot flue gas outlet of the burner is provided with a branch smoke exhaust port, which is connected with the air inlet at the lower part of the fluidized bed for transporting the high-temperature gas generated by the burner to the Fluidized bed as fluidizing medium.

As an improvement of the utility model, a jacket is provided outside the flaring section of the fluidized bed, and the inlet of the jacket is connected with the heat medium outlet of the heat exchanger.

As an improvement of the utility model, it also includes an air preheater and a blower, the hot air inlet of the air preheater is connected with the outlet of the jacket, the air inlet of the air preheater is connected with the blower, and the air of the air preheater The outlet is connected to the air inlet of the burner.

As an improvement of the utility model, a circulating fan is also included, the air inlet of the circulating fan is connected with the exhaust port of the cyclone separator, and the air outlet of the circulating fan is connected with the air inlet at the lower part of the fluidized bed.

Further, the heat exchanger is a silicon carbide heat exchanger.

Compared with the prior art, the utility model has the following advantages:

1. The gas generated by thermal cracking of the fluidized bed is used as the heat source of the system. After being burned by the burner, high-temperature flue gas is generated, and then the high-temperature flue gas is sent to the heat exchanger in the furnace to provide pyrolysis place for biomass materials through heat exchange. Heat demand, that is, the system uses its own gas to meet the heat required for pyrolysis in the furnace, which reduces operating costs compared to the pyrolysis method that uses external fuel and electric energy.

2. Using a fluidized bed, compared with a fixed bed reactor, improves the heat and mass transfer efficiency of the materials in the furnace. At the same time, using high-temperature gas as the fluidization medium avoids a large amount of nitrogen from being mixed into the biomass gas, and finally greatly improves the biomass. The calorific value and grade of gas have greatly expanded its application range; at the same time, the fluidized medium used is high-temperature gas produced by biomass itself, which avoids the subsequent separation process of nitrogen and gas, and greatly reduces operating costs.

3. The high-temperature gas used as the fluidization medium circulates into the fluidized bed, and the tar is catalytically cracked for the second time, greatly reducing its tar content.

4. After the high-temperature flue gas passes through the silicon carbide heat exchanger and jacket for heat exchange, it enters the air preheater to preheat the combustion air of the burner. If there is still residual heat after passing through the air preheater, it will be used as a material to enter The drying heat source in front of the furnace can dry and preheat the materials, so as to realize the multi-level utilization of energy and improve the energy utilization rate of the system.

5. The return material after the cyclone separation is passed through the star discharge valve and the screw feeder. The return material outlet is not directly connected to the furnace of the fluidized bed, but enters the hopper fed by the screw feeder and is mixed with the biomass material. Into the furnace, reducing the number of interfaces of the fluidized bed, simplifying the structural design and construction difficulty.

Description of drawings

Fig. 1 is a schematic diagram of a fluidized bed pyrolysis device for preparing high calorific value biomass gas according to the present invention.

Detailed ways

Below in conjunction with accompanying drawing and embodiment the utility model is further described. It can be understood that the specific embodiments described here are only used to explain the utility model, rather than limit the utility model. In addition, it should be noted that, for the convenience of description, only the part related to the present utility model is shown in the drawings but not the whole content.

Example

Please refer to Fig. 1, a fluidized bed pyrolysis device for preparing high calorific value biomass gas, including fluidized bed 1, cyclone separator 4, heat exchanger 10 and feeder 3, feeder 3 is used for crushing The dried biomass material is sent to the fluidized bed 1, the inlet of the cyclone separator 4 is connected with the top of the fluidized bed 1, the heat exchanger 10 is arranged in the dense phase section in the fluidized bed, and the heat exchanger 10 The heat required for pyrolysis is provided for biomass materials through heat exchange, and a booster fan 8 and a biomass gas burner 9 are also included. The exhaust port of the cyclone separator 4 is connected to the inlet of the booster fan 8, and the boost The air outlet of the fan 8 is connected with the air inlet of the burner 9 , and the hot flue gas outlet of the burner 9 is connected with the heat medium inlet of the heat exchanger 100 . Wherein, the heat exchanger 10 is a silicon carbide heat exchanger. The silicon carbide heat exchanger has excellent characteristics such as corrosion resistance, high temperature resistance, high thermal conductivity, high hardness, and wear resistance, and can increase the service life of the heat exchanger.

The working principle of the utility model: the gas produced by thermal cracking of the fluidized bed is used as the heat source of the system, and the high-temperature flue gas is generated after being burned by the burner, and then the high-temperature flue gas is sent to the heat exchanger in the fluidized bed furnace, through heat exchange To provide the heat required for pyrolysis of biomass materials, that is, the system uses its own gas to meet the heat required for pyrolysis in the furnace. Compared with the pyrolysis method using external fuel and electric energy, the operating cost is reduced.

In order to facilitate feeding, the feeder 3 is a screw feeder, and the feeding hopper of the screw feeder 3 is provided with a feeder 2 with a large inclination angle, and the feeder 2 with a large inclination angle is used for crushing and drying raw materials. The material feed is sent to the feed hopper of the screw feeder 3.

In this embodiment, in order to improve the utilization rate of energy, the ash separated by the cyclone separator 4 is mixed with the biomass material and then enters the fluidized bed. A screw feeder 6 is provided below the ash discharge port of the cyclone separator 4. , The screw feeder 6 is used to deliver the ash to the feed hopper of the screw feeder 3 . Moreover, the ash discharge port of the cyclone separator 4 is provided with a star discharge valve 5, the star discharge valve isolates the ash discharge pipe of the cyclone separator from the cyclone cylinder, and carries out quantitative and continuous feeding, which can avoid The toner particles of the ash material are light and sticky, which leads to the problem that the material is not smooth.

In one embodiment of the present utility model, the hot flue gas outlet of the burner 9 is provided with a branch smoke exhaust port, and the branch smoke exhaust port is connected with the air inlet at the lower part of the fluidized bed 1. When the temperature in the furnace is low, replace When the heat area is still not enough, it can be considered to directly introduce part of the high-temperature flue gas from the biomass burner into the air inlet at the lower part of the fluidized bed, and mix it with the fluidized medium to transport the high-temperature gas generated by the burner into the fluidized bed as a Fluidized medium to increase the temperature of the fluidized medium. Using high-temperature gas as the fluidization medium avoids a large amount of nitrogen mixed into the biomass gas, and ultimately greatly improves the calorific value and grade of the biomass gas, and its application range has been greatly expanded; at the same time, the fluidization medium used is produced by the biomass itself High-temperature gas avoids the subsequent nitrogen and gas separation process, and the operating cost will also be greatly reduced.

In order to improve heat exchange efficiency, in this embodiment, a jacket 11 is provided outside the flared section of the fluidized bed 1 , and the inlet of the jacket 11 is connected to the heat medium outlet of the heat exchanger 10 . The heat exchange effect is improved through the double heat exchange of the heat exchanger and the jacket.

And in the present embodiment, also comprise air preheater 13 and blower 12, the hot air inlet of air preheater 13 is connected with the outlet of jacket 11, the air inlet of air preheater 13 is connected with blower 12, the air The air outlet of the preheater 13 is connected to the air inlet of the burner 12. After the heat exchange between the heat exchanger and the jacket, the high-temperature flue gas enters the air preheater to preheat the combustion-supporting air, and the hot gas of the preheater exits the flue gas It can be directly discharged or used in the drying process of materials.

In the present embodiment, a circulating fan 7 is also included, and the air inlet of the circulating fan 7 is connected with the exhaust port of the cyclone separator 4, and the air outlet of the circulating fan 7 is connected with the air inlet at the bottom of the fluidized bed 1. The gas separated by the separator is used as the fluidization medium, which can avoid a large amount of nitrogen from being mixed into the biomass gas, and finally greatly improve the calorific value and grade of the biomass gas, and its application range has been greatly expanded.

In this embodiment, the exhaust port of the cyclone separator 4 is also connected to the exhaust pipe, and part of the gas after the dust removal by the cyclone separator 4 is pressurized by the booster fan, and then sent to the biomass burner and the hot air preheater. Co-combustion; part of the gas is sent to the fluidized bed by a high-temperature gas recirculation fan and used as a fluidization medium; the rest of the gas is sent to the gas storage tank for downstream processes, used for heat source, fluidization medium and biomass gas volume output by the system The ratio is 0.3:0.2:0.5 to 0.2:0.2:0.6.

The method for producing gas by using the above-mentioned fluidized bed pyrolysis device for preparing high calorific value biomass gas comprises the following steps:

Step 1: After pretreatment such as crushing and drying, the biomass material is sent to the feeding hopper of the screw feeder through a large inclination conveyor, and the screw feeder sends the material to the fluidized bed furnace for pyrolysis reaction.

Step 2: The biomass material is in a bubbling fluidized state in the fluidized bed. The fluidized medium is a part of the circulating biomass gas. On the surface of the bed, in the dense phase area with high particle density, the indirect heat exchange between the high-temperature flue gas and the furnace material is carried out through the silicon carbide heat exchanger and the jacket. The temperature in the furnace is controlled at 700-800 °C. In the presence of air, oxygen, water vapor, etc.), biomass fuel is cracked to produce liquid (bio-oil), solid (coke) and biomass gas rich in CO and H2;

The heat source of the pyrolysis reaction is high-temperature flue gas, and the temperature is required to be above 900°C. The indirect heat exchange through the silicon carbide heat exchanger provides heat for the furnace. When the system is started, the biomass gas burner burns the ignition fuel to generate high-temperature flue gas. When the system is running stably, biomass gas is used to generate high-temperature flue gas.

Step 3: The generated biomass gas enters the cyclone separator outside the furnace for dust removal, and the separated fly ash enters the feeding hopper of the screw feeder through the unloading valve and the screw feeder, and is mixed with the biomass material before being sent to into the fluidized bed furnace.

Step 4: Part of the gas after cyclone dedusting is pressurized by a high-temperature gas booster fan, and then sent to a biomass gas burner and premixed with hot air for combustion to generate high-temperature flue gas, which passes through a silicon carbide heat exchanger and jacket To provide heat for the fluidized bed furnace, when the temperature in the furnace is low and the heat exchange area is still insufficient, it can be considered to introduce part of the high-temperature flue gas from the outlet of the biomass burner directly into the air inlet of the fluidized bed and mix it with the fluidized medium. To increase the temperature of the fluidized medium; the other part is pressurized by the high-temperature gas recirculation fan, and enters the furnace from the air inlet of the fluidized bed to be used as the fluidized medium of the fluidized bed; the remaining part is sent to the gas storage tank for downstream processes , the volume ratio of biomass gas used for heat source, fluidized medium and system output is 0.3:0.2:0.5～0.2:0.2:0.6.

Step 5: After exchanging heat through the silicon carbide heat exchanger and the jacket, the high-temperature flue gas enters the air preheater to preheat the combustion-supporting air, and the flue gas at the outlet of the preheater can be directly discharged or used in the drying process of materials.

An example of a production test using a fluidized bed pyrolysis plant for the production of high calorific value biomass gas is as follows:

The raw material is granular bamboo processing biomass waste, and the start-up fuel is wood chips. When the system is running, the high-temperature gas booster fan and the biomass burner are first started to generate high-temperature flue gas by igniting the fuel, and the temperature in the fluidized bed furnace is reduced. Raise it to 800°C, feed the material timely and start the high-temperature gas circulation fan, control the bed temperature with the circulating air volume, control the bed temperature with the air volume, adjust the ratio of feeding and fluidizing air, and gradually transition to the normal operating parameters, among which, the biomass gas burner The high-temperature flue gas generated is 900-1000°C, the air is preheated to 320°C, and the flue gas discharge temperature is 200°C.

Granular biomass undergoes fluidization and thermal cracking reactions in the fluidized bed, and materials with a certain particle size enter the cyclone separator with high-temperature gas, and the separated gas is used as fluidization medium and heat source in proportions of 30% and 30% respectively. %.

The above-mentioned embodiment is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited by the above-mentioned embodiment, and any other changes, modifications, substitutions, combinations, Simplifications should be equivalent replacement methods, and all are included in the protection scope of the present invention.

Claims (9)

1. A fluidized bed pyrolysis device for preparing high calorific value biomass gas, including a fluidized bed, a cyclone separator, a heat exchanger and a feeder, the feeder is used to send the crushed and dried biomass material to the flow stream In the fluidized bed, the inlet of the cyclone separator is connected to the top of the fluidized bed, and the heat exchanger is arranged in the dense phase section of the fluidized bed. The heat exchanger provides the heat required for pyrolysis of the biomass material through heat exchange, It is characterized in that it also includes a booster fan and a biomass gas burner, the exhaust port of the cyclone separator is connected with the inlet port of the booster fan, the outlet port of the booster fan is connected with the inlet port of the burner, The hot flue gas outlet of the burner is connected with the heat medium inlet of the heat exchanger. 2. The fluidized bed pyrolysis device for preparing high calorific value biomass gas according to claim 1, characterized in that: the feeder is a screw feeder, and the feed hopper of the screw feeder is provided with a large Inclined feeder, large inclined feeder is used to send the crushed and dried biomass material to the feed hopper of the screw feeder. 3. The fluidized bed pyrolysis device for preparing high calorific value biomass gas according to claim 2, characterized in that: a screw feeder is provided below the ash discharge port of the cyclone separator, and the screw feeder is used to displace the ash Feed to the feed hopper of the screw feeder. 4. The fluidized bed pyrolysis device for preparing high calorific value biomass gas according to claim 3, characterized in that: a star discharge valve is provided at the ash discharge port of the cyclone separator. 5. The fluidized bed pyrolysis device for preparing high calorific value biomass gas according to claim 1, characterized in that: the hot flue gas outlet of the burner is provided with a branch smoke exhaust port, and the branch smoke exhaust port is connected with the fluidized gas outlet. The air inlet at the lower part of the bed is connected to transport the high-temperature gas generated by the burner into the fluidized bed as a fluidized medium. 6. The fluidized bed pyrolysis device for preparing high calorific value biomass gas according to claim 1, characterized in that: the outside of the flared section of the fluidized bed is provided with a jacket, and the inlet of the jacket is connected to the heat exchanger The heat medium outlet is connected. 7. The fluidized bed pyrolysis device for preparing high calorific value biomass gas according to claim 6, characterized in that: it also includes an air preheater and a blower, and the hot gas inlet of the air preheater is connected with the outlet of the jacket , the air inlet of the air preheater is connected with the blower, and the air outlet of the air preheater is connected with the air inlet of the burner. 8. The fluidized bed pyrolysis device for preparing high calorific value biomass gas according to claim 1, characterized in that: it also includes a circulating fan, the air inlet of the circulating fan is connected with the exhaust port of the cyclone separator, and the circulating fan The air outlet of the fluidized bed is connected with the air inlet at the lower part of the fluidized bed. 9. The fluidized bed pyrolysis device for preparing high calorific value biomass gas according to claim 1, characterized in that: the heat exchanger is a silicon carbide heat exchanger.