Biomass entrained-flow bed gasification system

Abstract

The utility model belongs to biomass gasification equipment, and relates to a biomass entrained-flow bed gasification system. The system comprises a pulverizing unit, a dense-phase conveying unit and a gasifying unit which are connected in sequence, wherein the pulverizing unit comprises a first crushing device, a modifying device and a second crushing device which are connected in sequence; the dense-phase conveying unit comprises a biomass powder bin and a lock hopper which are connected in sequence; the biomass powder bin is communicated with the second crushing device; the gasification unit comprises a burner, a gasification furnace and a chilling area which are connected in sequence; the burner is positioned at the top of the gasification furnace and is communicated with the lock hopper; a chilling area is arranged below the gasification furnace, and a synthesis gas outlet is formed in the chilling area; the bottom of the gasification unit is an ash outlet; a feeding tank or a feeding valve is arranged on a connecting line of the lock hopper and the burner, and the burner is communicated with the lock hopper through a pipeline provided with the feeding tank or the feeding valve. The system disclosed by the utility model has the advantages of low energy consumption in powder preparation and dense-phase conveying, high effective gas content, long operation period and the like.

Description

Technical Field

[0001] The utility model belongs to biomass gasification equipment, in particular to a biomass fluidized bed gasification system. Background Art

[0002] Biomass is organic matter converted by green plants using solar energy to absorb CO2 through photosynthesis, including agricultural and forestry waste and domestic garbage. It is a carbon-neutral renewable energy source.

[0003] Biomass gasification to produce syngas is the leading technology and core technology for biomass preparation of chemicals. According to different biomass gasification methods, it can be divided into fixed bed gasification, fluidized bed gasification and entrained bed gasification. Biomass entrained bed gasification technology has the characteristics of high reaction rate, large production capacity and easy pressurization, which is particularly suitable for large-scale biomass preparation of green chemicals projects.

[0004] However, there are some problems with the entrained-flow gasification technology, such as high energy consumption in the preparation and transportation of biomass powder, low effective gas content in the gasification product, low carbon conversion rate of the gasification reaction, and short operation cycle of the gasification equipment. Utility Model Content

[0005] The purpose of the utility model is to solve the problems raised in the background technology and to provide a biomass fluidized bed gasification system.

[0006] The utility model achieves the above-mentioned purpose through the following technical solutions.

[0007] The utility model provides a biomass fluidized bed gasification system, which comprises a pulverizing unit, a dense phase conveying unit and a gasification unit which are sequentially connected in a logistics sequence, wherein:

[0008] The powder making unit comprises a first crushing device, a modifying device, and a second crushing device which are sequentially connected along the material flow direction;

[0009] The dense phase conveying unit comprises a biomass powder bin and a lock bucket connected in sequence along the material flow direction; the biomass powder bin is connected to the second crushing device;

[0010] The gasification unit comprises a burner, a gasification furnace and a quenching area which are sequentially connected along the material flow direction; the burner is located at the top of the gasification furnace and is connected to the lock bucket of the dense phase conveying unit; the quenching area is below the gasification furnace and is provided with a syngas outlet; the bottom of the gasification unit is an ash outlet;

[0011] A material delivery tank or a material feeding valve is arranged on the connection line between the lock hopper and the burner, and the burner and the lock hopper are communicated with each other through a pipeline equipped with the material delivery tank or the material feeding valve.

[0012] In a preferred embodiment, when a feed valve is provided on the connection line between the lock hopper and the burner, the number of lock hoppers in the system is 2 or more, and each lock hopper is independently equipped with a feed valve.

[0013] In a preferred embodiment, the second crushing device is selected from the group consisting of a ball mill, a jet mill, a pressure roller mill, a ring roller mill, a fan mill, a hammer mill, a roller bowl mill, a roller ring mill, a rolling ball mill, a roller disc mill and a roller mill.

[0014] In a preferred embodiment, in the powder making unit, a silo pump and a filter are arranged downstream of the second crushing device along the material flow direction, the silo pump is provided with a first conveying gas inlet, and the filter is provided with an exhaust port; the filter is connected to the biomass powder silo.

[0015] Preferably, the filter is a gas-solid filter.

[0016] In a preferred embodiment, the inner wall of the gasifier is provided with a lining equipped with cooling circulating water, and the lining is provided with a cooling water outlet and a cooling water inlet.

[0017] In a preferred embodiment, the quenching area is provided with a quenching water inlet and a black water outlet.

[0018] In a preferred embodiment, a flushing water distribution pipe is provided in the quenching area.

[0019] In a preferred embodiment, a waste boiler for recovering sensible heat of the gasification reaction products is further included between the gasifier and the quenching zone.

[0020] Compared with the prior art, the utility model has the following beneficial effects:

[0021] 1. In the powder making unit, the biomass raw materials are successively crushed, modified and crushed twice, which greatly improves the relaxed density and bulk density of biomass with low energy consumption. Therefore, only a small amount of conveying gas is needed to realize the dense phase conveying of biomass powder, and also to increase the effective gas content in the gasification reaction products.

[0022] 2. In the powder making unit, the modification device and the second crushing device ensure the uniform distribution of cellulose, hemicellulose and lignin in the obtained biomass powder, ensuring the uniformity of each powder particle of the biomass powder during gasification, avoiding the escape of some powder from the gasifier due to excessive proportion of lignin before it has time to react, and ensuring a high carbon conversion rate of the gasification reaction.

[0023] 3. In the powder making unit, the setting of the silo pump and the filter can realize the long-distance and high-altitude transportation of biomass powder, so that the powder making unit and the dense phase conveying unit can be arranged at different positions and heights, reducing the requirements for the frame floor space and height, thereby reducing the frame investment.

[0024] 4. In the gasification unit, the setting of lining circulating water in the gasifier reduces the corrosion of the molten slag to the lining of the gasifier. The setting of flushing water in the quenching area extends the service life of the equipment and pipelines under high chlorine conditions. The setting of quenching water in the quenching area reduces the corrosion of high-concentration chloride ions to the equipment at high temperatures.

[0025] 5. In the gasification unit, the temperature of the gasification product leaving the waste boiler is increased to ensure that no alkali metal dust is deposited in the waste boiler section of the gasification unit, thereby achieving long-term safe and stable operation of the waste boiler. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A schematic diagram of a biomass entrained flow gasification system provided by the utility model;

[0027] Figure 2 A schematic diagram of another biomass fluidized bed gasification system provided by the utility model; wherein I-pulverizing unit; II-dense phase conveying unit; III-gasification unit;

[0028] 11-Raw material inlet; 12-First crushing device; 13-Modifying device; 14-Second crushing device; 15-First conveying gas inlet; 16-Storage pump; 17-Filter; 18-Exhaust port;

[0029] 21-biomass powder bin; 22-locking bucket; 23-dispensing tank; 24-feeding valve; 25-second conveying gas inlet;

[0030] 31 - gasifying agent inlet; 32 - burner; 33 - gasifier; 34 - waste boiler; 35 - quenching area; 36 - synthesis gas outlet; 37 - ash outlet. DETAILED DESCRIPTION

[0031] In order to facilitate the understanding of the present invention, the present invention will be further described below in conjunction with the embodiments. It should be understood that the following embodiments are only for a better understanding of the present invention and do not mean that the present invention is limited to the following embodiments.

[0032] The utility model provides a biomass entrained flow gasification system, and the utility model is further described below through drawings and specific implementation methods.

[0033] like Figure 1 As shown, the system includes a pulverizing unit (I), a dense phase conveying unit (II) and a gasification unit (III) which are connected in sequence according to a logistics sequence.

[0034] The powder making unit (1) comprises a first crushing device (12), a modifying device (13), and a second crushing device (14) which are sequentially connected along the material flow direction and are used for crushing and modifying the biomass raw material to obtain biomass powder with a certain particle size;

[0035] The first crushing device (12) is used to roughly crush the biomass raw material at the raw material inlet (11), and the rough crushing can be hammer crushing, grinding crushing, cutting, etc. The first crushing device (12) makes the particle size of the biomass ≤5mm.

[0036] The modification device (13) is used to modify the coarsely crushed material, for example, physical modification and / or chemical modification conventional in the art, such as extrusion molding, adding fillers, etc.

[0037] In the milling unit (I), the second crushing device (14) is selected from a ball mill, a jet mill, a pressure roller mill, a ring roller mill, a fan mill, a hammer mill, a roller bowl mill, a roller ring mill, a roller ball mill, a roller disc mill and a roller mill.

[0038] In some embodiments, the downstream of the second crushing device (14) includes a silo pump (16) and a filter (17) along the material flow direction. The silo pump (16) is provided with a first conveying gas inlet (15) for conveying the secondary crushed material to the filter (17) through the first conveying gas at the first conveying gas inlet (15), wherein the first conveying gas is a commonly used conveying gas in the art, such as N2 or CO2.

[0039] The filter (17) is used to screen out the portion of the material after secondary crushing that is suitable for dense phase transportation. The filter (17) is provided with an exhaust port (18); the filter (17) is connected to the biomass powder bin (21).

[0040] In a specific embodiment, the filter (17) is a gas-solid filter in the art, and the separated gas is discharged into the atmosphere from the exhaust port (18), and the separated biomass powder enters the biomass powder bin (21).

[0041] Arranging a bin pump (16) and a filter (17) in front of the biomass powder bin (21) of the dense phase conveying unit (II) can realize long-distance and high-altitude transportation of biomass powder, so that the powder making unit (I) and the dense phase conveying unit (II) can be arranged at different positions and heights, without arranging the second crushing device (14) above the biomass powder bin (16), thereby reducing the requirements for the frame footprint and height, thereby reducing the frame investment.

[0042] The dense phase conveying unit (II) comprises a biomass powder bin (21) and a lock hopper (22) which are sequentially connected along the material flow direction.

[0043] The biomass powder bin (21) is used to store the biomass powder prepared in the powder making unit (I) and to prepare the biomass powder for dense phase transportation.

[0044] The lock hopper (22) is used to densely transport the biomass powder stored in the biomass powder bin (21) to the downstream gasification unit (III).

[0045] like Figure 1 As shown, in some specific embodiments, the delivery flow of the biomass powder is controlled by arranging a feed tank (23) downstream of the lock hopper (22); Figure 2 As shown, in some other specific embodiments, the delivery flow rate of the biomass powder is controlled by arranging a feed valve (24) downstream of the lock hopper (22). The lock hopper (22) and the burner (32) are connected through a pipeline equipped with the feed tank (23) or the feed valve (24), and a second delivery gas inlet (25) is arranged on the pipeline.

[0046] The delivery tank (23) can control the delivery flow rate by adjusting the pressure difference between the delivery tank (23) and the downstream gasifier (33); the feeding valve (24) can control the delivery flow rate by adjusting the feeding rate of the lock hopper (22).

[0047] like Figure 2 As shown, in some specific embodiments, when the feeding valve (24) is used to control the conveying flow rate, the dense phase conveying unit (II) is equipped with two lock buckets (22). The two lock buckets can convey materials in an alternating manner, and each is equipped with its own independent feeding valve (24). The advantage of doing so is that when the biomass powder falls from the biomass powder bin (21) into the lock bucket (22), it is in a normal pressure state. Compared with the falling of materials under pressurized conditions, the falling of materials under normal pressure is smoother, avoiding the problem of bridging that is easy to occur under pressurized conditions, thereby ensuring the safety and stability of the dense phase conveying unit (II).

[0048] In another specific embodiment, when the feeding valve (24) is used to control the conveying flow rate, the dense phase conveying unit (II) is equipped with more than two lock hoppers (22), and each lock hopper (22) is equipped with its own independent feeding valve (24).

[0049] The biomass powder output from the lock hopper (22) is densely transported to the burner (32) of the following gasification unit (III) by the second transport gas entering through the second transport gas inlet (25); the second transport gas is a transport gas commonly used in the art, such as N2 or CO2.

[0050] The gasification unit (III) comprises a burner (32), a gasification furnace (33) and a quenching area (34) which are sequentially connected along the material flow direction.

[0051] The burner (32) is located at the top of the gasifier. The burner (32) is connected to the lock hopper (22) of the dense phase conveying unit (II) and is used to mix the oxygen-containing gasifying agent from the gasifying agent inlet (31) and the biomass powder from the lock hopper (22).

[0052] The gasifier (33) is a place where the biomass powder and the oxygen-containing gasifying agent undergo a gasification reaction, and high-temperature synthesis gas and molten slag are discharged after the reaction is completed.

[0053] The gasifier (33) contains an inner lining made of chromium-molybdenum steel. The inner lining is provided with a cooling water outlet and a cooling water inlet, so as to facilitate the introduction of circulating cooling water into the inner lining and avoid corrosion of the inner lining caused by molten slag with a high alkali metal content at high temperature.

[0054] Specifically, the cooling water makes the temperature of the lining ≤400°C, preferably the temperature ≤350°C.

[0055] A waste boiler (34) for recovering sensible heat of the gasification reaction product is also included between the gasifier (33) and the quenching area (35). The waste boiler (34) can recover the sensible heat of the high-temperature synthesis gas and produce steam as a by-product, thereby improving the heat utilization efficiency of the gasification unit (III).

[0056] Specifically, the temperature of the high-temperature synthesis gas at the outlet of the waste boiler (34) is ≥700°C to avoid the temperature range of alkali metal condensation and precipitation, which can ensure that no alkali metal dust is deposited in the waste boiler section of the gasification unit (III), thereby achieving long-term safe and stable operation of the radiation waste boiler; when the gasification reaction is carried out, the temperature of the high-temperature synthesis gas at the outlet of the waste boiler (34) is ≥800°C.

[0057] The quenching area (35) is provided with a quenching water distribution pipe, and the working temperature of the quenching area (35) is lowered by the quenching water, so that the high-temperature synthesis gas and molten slag can be quenched to obtain low-temperature synthesis gas and ash, and at the same time, the corrosion of chloride ions to the equipment is reduced.

[0058] In some embodiments, a flushing water distribution pipe is provided in the quenching area (35), and the flushing water can be used to flush the inner side of the shell and the internal parts (which are in a wet environment with liquid water) of the quenching area (35), so that these parts are always in a low chloride ion concentration environment. Ultimately, the service life of the equipment and pipelines under high chlorine conditions is extended, the material requirements of the gasification equipment are reduced, and the adaptability of the biomass gasification system to high-chlorine straw raw materials is ensured.

[0059] Furthermore, the quenching water makes the working temperature of the quenching area (35) ≤ 200°C; the quenching water reduces the temperature of the synthesis gas and ash to 100°C to 200°C before being discharged from the gasification unit (III).

[0060] In some embodiments, the quenching area (35) is also provided with a black water outlet for discharging quenching water and flushing water; the quenching area is also provided with a syngas outlet (36) after quenching.

[0061] In some embodiments, the ash produced after quenching is discharged from the ash outlet (37) located at the bottom of the gasification unit (III).

[0062] The following is attached Figure 1 The working process of the utility model is introduced by taking the gasification system shown as an example:

[0063] Screening and removing impurities from biomass raw materials such as straw, and then performing a primary crushing in a first crushing device (12) to obtain a primary crushed material;

[0064] The primary crushed material is extruded and formed in a modification device (13) to obtain straw pellets;

[0065] The straw pellets are crushed for a second time in a second crushing device (14) to obtain straw powder;

[0066] The biomass powder is transported to the filter (17) through the N2 entering through the first transport gas inlet (15) by using a silo pump (16) for gas-solid filtration to obtain straw powder suitable for dense phase transport;

[0067] The straw powder is transported to a biomass powder bin (21) for storage, and then the straw powder in the biomass powder bin (21) is input into a lock hopper (22);

[0068] The lock hopper (22) is pressurized and the straw powder in the lock hopper (22) is densely transported to the burner (32) by using CO2 gas from the second transport gas inlet (25), wherein the flow rate of the dense phase transport is controlled by the feed tank (23); at the same time, external oxygen is transported to the burner (32);

[0069] The straw powder and oxygen enter the gasifier (33) through the burner (32) to undergo a gasification reaction, thereby obtaining high-temperature synthesis gas and molten slag;

[0070] The high-temperature synthesis gas enters the waste boiler (34) and exchanges heat with boiler water before leaving the waste boiler (34) and entering the quenching area (35) for quenching to obtain low-temperature synthesis gas; at the same time, the molten slag is quenched in the quenching area (35) to obtain ash slag;

[0071] The low-temperature synthesis gas is discharged from the synthesis gas outlet (36), and the ash is discharged from the ash outlet (37).

[0072] The gasification system of the utility model significantly reduces power consumption in the process of preparing biomass powder and transporting biomass powder to the gasification unit, showing a higher energy efficiency advantage; moreover, in the gasification reaction, the system also shows a high carbon conversion rate and effective gas content, ensuring the high efficiency of gasification efficiency. In addition, the various equipment of the gasification unit of the gasification system has a longer service life, further improving the reliability and economy of the system.

Claims

1. A biomass entrained flow gasification system, comprising a pulverizing unit, a dense phase conveying unit and a gasification unit connected in sequence according to a logistic sequence, characterized in that: The powder making unit comprises a first crushing device, a modifying device, and a second crushing device which are sequentially connected along the material flow direction; The dense phase conveying unit comprises a biomass powder bin and a lock bucket connected in sequence along the material flow direction; the biomass powder bin is connected to the second crushing device; The gasification unit comprises a burner, a gasification furnace and a quenching area which are sequentially connected along the material flow direction; the burner is located at the top of the gasification furnace and is connected to the lock bucket of the dense phase conveying unit; the quenching area is below the gasification furnace and is provided with a syngas outlet; the bottom of the gasification unit is an ash outlet; A material delivery tank or a material feeding valve is arranged on the connection line between the lock hopper and the burner, and the burner and the lock hopper are communicated with each other through a pipeline equipped with the material delivery tank or the material feeding valve.

2. The biomass entrained flow gasification system according to claim 1, characterized in that: When a feed valve is provided on the connection line between the lock hopper and the burner, the number of the lock hoppers in the system is 2 or more, and each lock hopper is independently equipped with a feed valve.

3. The biomass entrained flow gasification system according to claim 1, characterized in that: The second crushing device is selected from the group consisting of a ball mill, a jet mill, a pressure roller mill, a ring roller mill, a fan mill, a hammer mill, a roller bowl mill, a roller ring mill, a rolling ball mill, a roller disc mill and a roller mill.

4. The biomass entrained flow gasification system according to claim 1, characterized in that: In the powder making unit, a silo pump and a filter are arranged downstream of the second crushing device along the material flow direction, the silo pump is provided with a first conveying gas inlet, and the filter is provided with an exhaust port; the filter is connected to the biomass powder silo.

5. The biomass entrained flow gasification system according to claim 4, characterized in that: The filter is a gas-solid filter.

6. The biomass entrained flow gasification system according to claim 1, characterized in that: The inner wall of the gasifier is provided with a lining equipped with cooling circulating water, and the lining is provided with a cooling water outlet and a cooling water inlet.

7. The biomass entrained flow gasification system according to claim 1, characterized in that: The quenching area is provided with a quenching water inlet and a black water outlet.

8. The biomass entrained flow gasification system according to claim 1, characterized in that: A flushing water distribution pipe is arranged in the quenching area.

9. The biomass entrained flow gasification system according to claim 1, characterized in that: A waste pot for recovering sensible heat of gasification reaction products is also included between the gasifier and the quenching zone.

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