Semi-waste heat boiler heat recovery gasification system and method

Abstract

A semi-waste heat boiler heat recovery gasification system and method. The method comprises: using a gasification chamber to gasify biomass and an oxidant, so as to generate a high-temperature raw syngas and liquid slag; outputting the liquid slag into a slag bath chamber by means of a radiant waste heat boiler and outputting the high-temperature raw syngas to a quencher by means of a gas outlet of the radiant waste heat boiler; quenching and filtering the high-temperature raw syngas by means of the quencher; and transmitting part of the quenched raw syngas to a circulation gas inlet of the radiant waste heat boiler, so as to form, in the radiant waste heat boiler, a mixed gas of the quenched raw syngas and the high-temperature raw syngas generated by the gasification chamber, thereby reducing the temperature of the high-temperature raw syngas. By using low-temperature syngas circulation and mixing with the high-temperature raw syngas, the temperature at the outlet of the radiant waste boiler can be flexibly adjusted, and the viscosity of fly ash is reduced; furthermore, surface solidification of a gaseous alkali metal substance is promoted, thereby effectively preventing ash deposition on the radiant waste heat boiler.

Description

A semi-waste boiler heat recovery gasification system and method Technical Field

[0001] This invention relates to the field of biomass fluidized bed gasification technology, and in particular to a semi-waste boiler heat recovery gasification system and method. Background Technology

[0002] Biomass or biomass carbon (non-coal) powder is converted into high-quality crude syngas through fluidized bed gasification technology, achieving the industrial goal of converting biomass or carbonized biomass into high-quality crude syngas. Biomass powder, oxygen, and steam are fed into the gasifier through a gasification burner, where a non-catalytic partial oxidation reaction occurs under high temperature and pressure, generating high-temperature crude syngas and molten ash.

[0003] In fluidized bed gasification technology using pulverized coal as raw material, a gasification-quench process is commonly used for high-temperature gas sensible heat recovery. The gasification-quench process involves the high-temperature crude syngas and molten ash in the gasification chamber of the gasifier being cooled by quench water before entering the quench chamber water bath. The high-temperature crude syngas, initially 1200–1600℃, cools to 200–300℃, while the molten ash is cooled and solidified by the quench water and enters the water bath.

[0004] In this gasification-quenching process, the sensible heat recovery efficiency of the high-temperature gas is low, the water system circulation volume is large, the fine ash content is high, the equipment and pipelines are severely eroded, and the discharge of solid waste and wastewater is large.

[0005] Currently, there is a lack of efficient solutions for recovering the sensible heat of high-temperature gases in biomass gasification processes. Summary of the Invention

[0006] The purpose of this invention is to provide a semi-waste boiler heat recovery gasification system and method to at least partially solve the above-mentioned problems of the prior art.

[0007] To achieve the above objectives, the present invention provides a semi-waste boiler heat recovery gasification system, comprising a gasification chamber, a radiant waste boiler, a slag pool chamber, a quencher, and a circulating gas treatment device, wherein...

[0008] The gasification chamber is used to gasify the mixture of biomass and oxidant to produce high-temperature crude syngas and liquid slag.

[0009] The radiant waste boiler is connected to the gasification chamber, receiving the high-temperature crude syngas and liquid slag generated in the gasification chamber. It is equipped with a gas outlet and a circulating gas inlet. The high-temperature crude syngas is output to the quencher through the gas outlet, and the crude syngas input by the circulating gas treatment device is received through the circulating gas inlet. A slag outlet is set up to connect to the slag pool, and slag is output into the slag pool.

[0010] The slag pool chamber is connected to the radiant waste boiler and receives the molten slag that passes through the radiant waste boiler.

[0011] The quencher is connected to the gas outlet of the radiant waste boiler and receives the high-temperature crude syngas output from the radiant waste boiler. The quencher is equipped with a quenching liquid, and the outlet of the high-temperature crude syngas is located below the surface of the quenching liquid. The syngas outlet is located above the quenching liquid in the quencher, and the quenched crude syngas is output through the syngas outlet.

[0012] The circulating gas treatment device is connected to the circulating gas inlet of the radiant waste boiler. It is used to transfer a portion of the quenched crude syngas to the circulating gas inlet of the radiant waste boiler, forming a mixture of the quenched crude syngas and the high-temperature crude syngas generated in the gasification chamber inside the radiant waste boiler, thereby reducing the temperature of the high-temperature crude syngas.

[0013] In a preferred embodiment, the system further includes a syngas scrubbing device connected to the quencher and the circulating gas treatment device, for scrubbing the crude syngas quenched by the quencher with a scrubbing liquid in a multi-layer tray.

[0014] The circulating gas treatment unit is connected to the syngas scrubbing unit, receives the crude syngas after scrubbing by the syngas scrubbing unit, and transfers a portion of the quenched and scrubbed crude syngas to the circulating gas inlet of the radiant waste boiler.

[0015] In a preferred embodiment, the circulating gas treatment device includes a compression device for pressurizing the crude syngas output to the circulating gas inlet of the radiant waste boiler, and outputting the pressurized crude syngas to the circulating gas inlet of the radiant waste boiler.

[0016] In a preferred embodiment, the recirculating gas treatment device is also used to regulate the temperature of the crude syngas.

[0017] In a preferred embodiment, a slag outlet is provided below the quencher to output wastewater that meets the first condition and to recycle wastewater that meets the second condition back into the quencher.

[0018] In a preferred embodiment, the crude syngas includes one or more of fly ash, CO and H2, and HCl, with the first condition including an HCl concentration threshold.

[0019] In a preferred embodiment, the gasification chamber includes a top burner for injecting a mixture of biomass and oxidant into the gasification chamber.

[0020] Another aspect of the present invention provides a method for semi-waste boiler heat recovery gasification, comprising:

[0021] The mixture of biomass and oxidant is gasified in a gasification chamber to generate high-temperature crude syngas and liquid slag.

[0022] The molten slag is discharged to the slag pool chamber through the lower pipe of the radiant waste boiler;

[0023] High-temperature crude syngas is output to the quencher through the gas outlet of the radiant waste boiler;

[0024] The high-temperature crude syngas is quenched and filtered by the quenching liquid in the quencher, and the crude syngas is output through the pipe outlet above the quenching liquid.

[0025] A portion of the quenched crude syngas is transferred to the circulating gas inlet of the radiant waste boiler, where a mixture of the quenched crude syngas and the high-temperature crude syngas generated in the gasification chamber is formed, thereby reducing the temperature of the high-temperature crude syngas.

[0026] In a preferred embodiment, the method further includes pressurizing the crude syngas output to the recirculation gas inlet of the radiant waste cooker.

[0027] In a preferred embodiment, the method further includes: injecting a mixture of biomass and oxidant into the gasification chamber through a top burner.

[0028] Compared with the prior art, the present invention has at least the following advantages:

[0029] By employing a semi-waste boiler heat recovery gasifier and using low-temperature syngas circulation to mix with high-temperature crude syngas, the outlet temperature of the radiant waste boiler can be flexibly adjusted, reducing fly ash viscosity and promoting surface solidification of gaseous alkali metals, effectively preventing ash accumulation in the radiant waste boiler. At the same time, the quenching method completely avoids ash deposition and coupled chlorine corrosion in the convective waste boiler under high alkali-acid ratio conditions, which can significantly improve the stability of the device. Attached Figure Description

[0030] Figure 1 is a schematic diagram of the structure of the semi-waste boiler heat recovery gasification system provided in an embodiment of the present invention.

[0031] Figure 2 is a schematic diagram of the structure of a semi-waste boiler heat recovery gasification system provided in another embodiment of the present invention.

[0032] Figure 3 is a schematic flowchart of the semi-waste boiler heat recovery gasification method provided in an embodiment of the present invention. Detailed Implementation

[0033] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0034] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be used interchangeably where appropriate to understand the embodiments of the invention described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a product or device comprising a series of units is not necessarily limited to those explicitly listed, but may include other units not explicitly listed or inherent to such product or device.

[0035] In this invention, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing the invention and its embodiments, and are not intended to limit the indicated devices, elements, or components to having a specific orientation, or to be constructed and operated in a specific orientation.

[0036] Furthermore, in addition to indicating direction or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in certain situations to indicate a dependency or connection. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0037] Furthermore, the terms "installation," "setup," "equipped with," "connection," "linking," and "socketing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0038] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0039] In fluidized bed gasification application technology, there are waste heat boiler processes with high heat recovery efficiency, including both semi-waste boiler and fully waste boiler processes.

[0040] In the application technology of fluidized bed gasification using pulverized coal as raw material, the semi-waste boiler process refers to the process where the high-temperature crude syngas and molten ash from the gasification chamber of the gasifier first enter the waste boiler section of the gasifier. Cooling water is present in the heat exchange tubes of the waste boiler. After heat exchange with the cooling water, the temperature of the high-temperature crude syngas drops to 600–650℃, and then it enters the water bath of the gasifier's quench chamber for further cooling and washing, where the temperature drops to 200–300℃. The ash also enters the water. The full waste boiler process refers to the process where the gasification chamber outlet of the gasifier is sequentially connected to a radiant waste boiler and a convective waste boiler, achieving full heat recovery of the high-temperature crude syngas through these two stages. Specifically, a cyclone separator is connected between the radiant and convective waste boilers. The high-temperature crude syngas exiting the gasification chamber of the gasifier first enters the radiant waste boiler section of the gasifier for heat exchange, while the coarse ash enters the gasifier's ash discharge pool. The syngas then enters the cyclone separator for gas-solid separation, and the separated syngas is finally sent to the convective waste boiler for heat exchange to achieve the goal of full heat recovery.

[0041] However, in the semi-waste boiler process, the sensible heat recovery of high-temperature gas is still not complete, and all ash and slag are eventually discharged into the water system, which can easily cause blockage and erosion of subsequent equipment and pipelines. In the full waste boiler process, the temperature of the crude syngas exiting the radiant waste boiler is relatively high, resulting in greater fly ash viscosity. After entering the convective waste boiler, it will stick to the outer wall of the heat exchange tube, and gaseous alkali metal substances will be deposited, affecting the heat exchange effect.

[0042] This invention provides a semi-waste boiler heat recovery gasification system. Using biomass or biomass carbon as raw material, it achieves the conversion of low-order energy into high-order syngas through fluidized bed gasification technology. The conversion process must address the characteristics of the biomass raw material, including the high alkali metal content in the ash and the high chloride content in elemental analysis. A reasonable process organization in gasification and subsequent syngas treatment is crucial to ensuring the overall safe operation of the gasification unit. The applicability of relevant process configurations is confirmed for different biomass properties. In this embodiment, the system efficiently recovers the sensible heat of the high-temperature gas, allowing for flexible adjustment of the high-temperature gas temperature at the radiant waste boiler outlet, reducing fly ash viscosity and promoting the cooling of gaseous alkali metals. It eliminates the need for a convective waste boiler, avoiding instability in industrial production. Furthermore, it employs a syngas quencher washing process at approximately 600°C followed by a syngas washing process, preventing the adhesion and corrosion of alkali metals and eutectic alkali metals to the convective waste boiler.

[0043] Example 1

[0044] This invention provides a semi-waste boiler heat recovery gasification system. Figure 1 shows a schematic diagram of the system. As shown in Figure 1, the system includes a gasification chamber 10, a radiant waste boiler 20, a slag pool chamber 30, a quencher 40, and a circulating gas treatment device 50.

[0045] Gasification chamber 10 is used to gasify the mixed biomass and oxidant to generate high-temperature crude syngas and liquid slag;

[0046] The radiant waste boiler 20 is connected to the gasification chamber 10 and receives the high-temperature crude syngas and liquid slag generated in the gasification chamber 10. It is equipped with a gas outlet 21 and a circulating gas inlet 22. The high-temperature crude syngas is output to the quencher through the gas outlet 21 and the crude syngas input by the circulating gas treatment device 50 is received through the circulating gas inlet 22. A slag outlet is provided and connected to the slag pool chamber 30 to output slag into the slag pool chamber.

[0047] The slag pool chamber 30 is connected to the radiant waste pot 20 and receives the molten slag passing through the radiant waste pot;

[0048] The quencher 40 is connected to the gas outlet 21 of the radiant waste boiler 20 and receives the high-temperature crude synthesis gas output from the radiant waste boiler; the quencher is equipped with a quenching liquid 41, and the outlet of the high-temperature crude synthesis gas pipe 42 is located below the liquid surface of the quenching liquid 41; a synthesis gas outlet 43 is provided above the quenching liquid in the quencher, and the quenched crude synthesis gas is output through the synthesis gas outlet 43.

[0049] The circulating gas treatment device 50 is connected to the circulating gas inlet 22 of the radiant waste boiler 20. It is used to transfer a portion of the quenched crude syngas to the circulating gas inlet 22 of the radiant waste boiler, forming a mixed gas of the quenched crude syngas and the high-temperature crude syngas generated in the gasification chamber in the radiant waste boiler 20, thereby reducing the temperature of the high-temperature crude syngas.

[0050] In a preferred embodiment, the system may further include a syngas scrubbing device, including a multi-layer tray connected to a quencher and a circulating gas treatment device, for scrubbing the crude syngas quenched by the quencher with a scrubbing liquid in the multi-layer tray.

[0051] The circulating gas treatment unit is connected to the syngas scrubbing unit, receives the crude syngas after scrubbing by the syngas scrubbing unit, and transfers a portion of the quenched and scrubbed crude syngas to the circulating gas inlet of the radiant waste boiler.

[0052] At this point, the crude syngas quenched by the quencher first enters the syngas scrubbing device for scrubbing. After scrubbing, part of the crude syngas enters the circulating gas treatment device, and part of it is output by the system and enters the subsequent process section.

[0053] In a preferred embodiment, the circulating gas treatment device may further include a compression device for pressurizing the crude syngas output to the circulating gas inlet of the radiant waste boiler, and outputting the pressurized crude syngas to the circulating gas inlet of the radiant waste boiler.

[0054] In a preferred embodiment, the circulating gas treatment device can also be used to regulate the temperature of the crude syngas. The temperature of the crude syngas can be flexibly adjusted, for example, set to half the temperature of the high-temperature crude syngas. This effectively reduces the temperature of the high-temperature crude syngas generated in the gasification chamber while preventing adverse reactions caused by excessively low temperatures.

[0055] In a preferred embodiment, a slag outlet is provided below the quencher to discharge wastewater that meets a first condition, and to recycle wastewater that meets a second condition back into the quencher. The first and second conditions can be impurity concentration thresholds in the wastewater. Two impurity concentration thresholds can be set, one higher and one lower. Wastewater exceeding the lower threshold is discharged and then recycled back into the quencher. For example, a circulation inlet can be provided above the quencher, while wastewater exceeding the higher threshold is discharged.

[0056] In a preferred embodiment, the system may further include a wastewater treatment device, which is equipped with two or more flash evaporation mechanisms, settling tanks, and filtration mechanisms to treat wastewater that meets the first condition.

[0057] In a preferred embodiment, the crude syngas includes one or more of fly ash, CO, and H2, as well as HCl, with a first condition including an HCl concentration threshold. That is, wastewater with a concentration greater than the HCl concentration threshold is discharged to a wastewater treatment device.

[0058] In a preferred embodiment, the gasification chamber includes a top burner 11 for injecting biomass and oxidant into the gasification chamber. The top burner and injection feeding method can enhance the mixing of materials in the gasification chamber, improve the flow field distribution inside the gasification chamber, and are simple to operate and easy to control, greatly reducing operating costs.

[0059] In a preferred embodiment, the slag chamber includes cooling water to cool and solidify the liquid molten slag. It may also include a slag remover for solid-liquid separation of the molten slag within the slag chamber.

[0060] In this embodiment, by using a semi-waste boiler heat recovery gasification furnace and using low-temperature syngas circulation to mix with high-temperature crude syngas, the outlet temperature of the radiant waste boiler can be flexibly adjusted, reducing fly ash viscosity and promoting surface solidification of gaseous alkali metal substances, effectively preventing ash accumulation in the radiant waste boiler. At the same time, the quenching method completely avoids ash deposition and coupled chlorine corrosion in the convective waste boiler under high alkali-acid ratio conditions, which can significantly improve the stability of the device.

[0061] Example 2

[0062] This invention provides a preferred semi-waste boiler heat recovery gasification system, and Figure 2 shows a schematic diagram of the system. As shown in Figure 2, the system includes a gasification chamber 10, a radiant waste boiler 20, a slag pool chamber 30, a quencher 40, a circulating gas treatment device 50, a syngas scrubbing device 60, and a wastewater treatment device 70. The specific structure of each part can be referred to Figure 1.

[0063] Among them, the gasification chamber 10 is used to gasify the mixed biomass and oxidant to generate high-temperature crude syngas and liquid slag.

[0064] The gasification chamber 10 is equipped with a top burner 11, which supplies biomass carbon powder and oxidant to the gasification chamber. Biomass carbon powder from the pulverizing unit is conveyed to the top burner 11 of the gasifier via a dense phase of hot inert gas, and an oxygen-steam mixture is also fed into the burner 11 as the gasifying agent. The burner 11 can inject biomass and oxidant into the gasification chamber using a jet feeding method. The top burner and jet feeding method enhance the mixing of materials in the gasification chamber, improve the internal flow field distribution, and are simple and easy to control, significantly reducing operating costs.

[0065] Biomass carbon powder, oxygen, and steam are uniformly mixed in the gasification chamber 10 of the gasifier, and then undergo a non-catalytic partial oxidation reaction at approximately 1200–1400°C and 4.0 MPaG to generate high-temperature crude syngas and liquid slag. The gasification chamber is equipped with water-cooled wall coils filled with saturated boiler water to protect the furnace shell from overheating. Note that 1200–1400°C and 4.0 MPaG are merely preferred reaction parameters and are not intended to limit the reaction conditions of this invention.

[0066] The radiant waste boiler 20 is located below the gasification chamber 10, with its top connected to the bottom of the gasification chamber 10. It receives the high-temperature crude syngas and liquid slag generated in the gasification chamber 10. The side wall is provided with a gas outlet 21 and a circulating gas inlet 22. The high-temperature crude syngas is output to the quencher through the gas outlet 21, and the crude syngas input by the circulating gas treatment device 50 is received through the circulating gas inlet 22. This forms a mixture of quenched crude syngas and high-temperature crude syngas generated in the gasification chamber within the radiant waste boiler 20, thereby reducing the temperature of the high-temperature crude syngas. The lower part is provided with a slag outlet connected to the slag pool chamber 30, which outputs slag into the slag pool chamber.

[0067] A narrow pipe channel can be installed in the lower section of the gasification chamber to connect to the radiant waste boiler 20 below. Vertical heat exchange tubes are installed inside the radiant waste boiler 20, and saturated boiler water is placed inside the heat exchange tubes. Molten slag flows downward into the slag pool chamber through the radiant waste boiler.

[0068] The slag pool chamber 30, located below the radiant waste boiler, is connected to the radiant waste boiler 20 via a pipe at its top, receiving the molten slag passing through the radiant waste boiler. The bottom outlet of the radiant waste boiler is connected to the top inlet of the slag pool chamber. The molten slag flows downwards through the radiant waste boiler and rapidly cools and solidifies upon encountering quench water in the slag pool chamber 30. It is periodically discharged, and the temperature of the quench water can be 200 degrees Celsius. A slag skimmer may also be included for solid-liquid separation of the molten slag within the slag pool chamber.

[0069] The quencher 40 is connected to the gas outlet 21 of the radiant waste boiler 20 and receives the high-temperature crude syngas output from the radiant waste boiler. The quencher is equipped with a quenching liquid 41, and the outlet of the high-temperature crude syngas pipe 42 is located below the surface of the quenching liquid 41. A syngas outlet 43 is located above the quenching liquid in the quencher, and the quenched crude syngas is output through the syngas outlet 43.

[0070] A slag-water outlet can be installed below the quencher to discharge wastewater that meets the first condition, and to recycle wastewater that meets the second condition back into the quencher. The first and second conditions can be threshold values ​​for impurity concentrations in the wastewater; two threshold values ​​can be set, one higher and one lower. Wastewater exceeding the lower threshold is discharged and then recycled back into the quencher. The crude syngas entering the quencher may contain fly ash, HCl, CO, and H2, etc. The fly ash is washed and settled in the quencher along with HCl, producing ash water. The first and second conditions may include HCl concentration threshold values.

[0071] Syngas scrubbing device 60, connected to quencher 40 and circulating gas treatment device 50, is used to scrub the crude syngas quenched by the quencher with scrubbing liquid in multi-layer trays. A portion of the quenched and scrubbed crude syngas is input into circulating gas treatment device 50, and the other portion is output of the system to the next stage, such as output to the boundary area.

[0072] The circulating gas treatment device 50 is connected to the circulating gas inlet 22 of the radiant waste boiler 20 and the syngas scrubbing device 60. It receives the crude syngas after scrubbing by the syngas scrubbing device 60 and transmits the received crude syngas to the circulating gas inlet of the radiant waste boiler. The circulating gas treatment device 50 may include a compression device for pressurizing the crude syngas output to the circulating gas inlet of the radiant waste boiler and outputting the pressurized crude syngas to the circulating gas inlet of the radiant waste boiler.

[0073] Wastewater treatment device 70 is connected to quencher 40 and is used to treat the wastewater output from quencher 40. For example, wastewater treatment device 70 is equipped with a two-stage flash evaporation mechanism, a settling tank and a filtration mechanism. After the ash water undergoes two-stage flash evaporation, it is sent to the settling tank for sedimentation, and then separated by plate filtration. Finally, it is sent out of the factory area as a by-product or waste.

[0074] When the high-temperature crude syngas and molten ash leave the gasification chamber and enter the radiant waste boiler, it is generally necessary to ensure that the temperature of the crude syngas and fly ash at the lower outlet of the radiant waste boiler is maintained within a suitable range. Otherwise, the following effects may occur: When the high-temperature crude syngas and molten fly ash enter the convective waste boiler and encounter the lower-temperature heat exchange tubes, the fly ash is likely to adhere to the outer wall of the heat exchange tubes, affecting the heat exchange effect; In a high-temperature environment, when gaseous alkali metal substances encounter the heat exchange tubes of the convective waste boiler, alkali metal deposition and subsequent chloride corrosion are likely to occur, ultimately causing damage to the heat exchange tubes of the convective waste boiler.

[0075] In this embodiment of the invention, the washed low-temperature crude syngas is pressurized by a compressor and sent to the radiant waste boiler section through a circulating gas treatment device. It is mixed with the high-temperature crude syngas to achieve the purpose of cooling, ensuring that the crude syngas at the outlet of the radiant waste boiler is stable within the optimal temperature range, reducing fly ash viscosity, reducing fly ash adhesion on the heat exchange tubes of the convective waste boiler, and ensuring that gaseous alkali metal substances are solidified in the radiant waste boiler section, thereby avoiding ash accumulation in the convective waste boiler.

[0076] Moreover, the top-mounted burner in this embodiment of the invention enhances the mixing of materials in the gasification chamber, improves the flow field distribution inside the gasification chamber, and is simple and easy to operate, greatly reducing operating costs.

[0077] Example 3

[0078] Based on the same technical concept as the above-described device embodiments, this embodiment of the invention also provides a semi-waste boiler heat recovery gasification method, as shown in Figure 3, the method comprising:

[0079] Step 31: Gasify the mixed biomass and oxidant in the gasification chamber to generate high-temperature crude syngas and liquid slag.

[0080] Step 32: The liquid molten slag is output to the slag pool chamber through the lower pipe of the radiant waste boiler;

[0081] Step 33: High-temperature crude syngas is output to the quencher through the gas outlet of the radiant waste boiler;

[0082] Step 34: The high-temperature crude synthesis gas is quenched and filtered by the quenching liquid in the quencher, and the crude synthesis gas is output through the pipe outlet above the quenching liquid.

[0083] Step 35: A portion of the quenched crude syngas is transferred to the circulating gas inlet of the radiant waste boiler, forming a mixture of the quenched crude syngas and the high-temperature crude syngas generated in the gasification chamber within the radiant waste boiler, thereby reducing the temperature of the high-temperature crude syngas.

[0084] In this method, step 35 may further include:

[0085] The crude syngas output to the circulating gas inlet of the radiant waste boiler is pressurized.

[0086] The method may also include:

[0087] Biomass and oxidant are injected into the gasification chamber through a top-mounted burner.

[0088] To facilitate understanding, an example process is given below:

[0089] Biomass carbon powder from the pulverizing unit is transported to the burner 11 at the top of the gasifier via a thermal inert gas dense phase, and an oxygen-steam mixture is also fed into the burner 11 as a gasifying agent.

[0090] After biomass carbon powder, oxygen and steam are mixed evenly in the gasification chamber 10 of the gasifier, a non-catalytic partial oxidation reaction is carried out at about 1200-1400℃ and 4.0MPaG to generate high-temperature crude syngas and liquid slag. The gasification chamber 10 is equipped with water-cooled wall coils, and the coils are filled with saturated boiler water to protect the gasifier shell from overheating.

[0091] Below the gasification chamber 10 is the radiant waste boiler 20. The vertical heat exchange tubes of the radiant waste boiler 20 contain saturated boiler water. The molten slag flows downward through the radiant waste boiler 20 and is rapidly cooled and solidified upon encountering quench water in the slag pool chamber 30, and is periodically discharged. The crude syngas and fly ash enter the quencher 40 for dechlorination.

[0092] After the crude syngas and fly ash leave the gasifier radiant waste boiler 20, they enter the quencher 40 to remove HCl and fly ash. Then, in the syngas scrubbing device 60, they come into direct contact with process water for washing and cooling. Part of the syngas is sent to the downstream section, while the other part is pressurized by the circulating gas compression device 50 and circulated back to the radiant waste boiler 20 to mix with the high-temperature crude syngas generated in the gasification chamber, so that the temperature at the crude syngas outlet of the radiant waste boiler 20 is maintained within a better range.

[0093] The ash water washed by the quencher 40 is sent to the environmental protection unit for concentration and reuse after energy recovery in the wastewater treatment unit 70.

[0094] In this embodiment of the invention, the washed, low-temperature crude syngas is pressurized by a compressor and sent to the radiant waste boiler section via a circulating gas treatment device. It mixes with the high-temperature crude syngas to achieve cooling, ensuring the crude syngas at the radiant waste boiler outlet remains within the optimal temperature range. This reduces fly ash viscosity and adhesion to the heat exchange tubes of the convective waste boiler, while simultaneously ensuring the solidification of gaseous alkali metals in the radiant waste boiler section, thus preventing ash accumulation in the convective waste boiler. Furthermore, this embodiment employs a top-mounted burner to enhance material mixing within the gasification chamber, improve the internal flow field distribution, and simplify operation and control, significantly reducing operating costs.

[0095] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Those skilled in the art should understand that modifications can be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A semi-waste boiler heat recovery gasification system, characterized in that, It includes a gasification chamber, a radiant waste boiler, a slag pool chamber, a quencher, and a circulating gas treatment unit, among which, The gasification chamber is used to gasify the mixed biomass and oxidant to generate high-temperature crude syngas and liquid slag. The radiant waste boiler is connected to the gasification chamber and receives the high-temperature crude syngas and the liquid slag generated in the gasification chamber. It is provided with a gas outlet and a circulating gas inlet. The high-temperature crude syngas is output to the quencher through the gas outlet, and the crude syngas input by the circulating gas treatment device is received through the circulating gas inlet. A slag outlet is provided and connected to the slag pool chamber to output the liquid slag into the slag pool chamber. The slag pool chamber is connected to the radiant waste pot and receives the liquid molten slag passing through the radiant waste pot. The quencher is connected to the gas outlet of the radiant waste boiler and receives the high-temperature crude syngas output from the radiant waste boiler; a quenching liquid is provided inside the quencher, and the pipeline outlet of the high-temperature crude syngas is located below the liquid surface of the quenching liquid; a syngas outlet is provided above the quenching liquid in the quencher, and the quenched crude syngas is output through the syngas outlet. The circulating gas treatment device is connected to the circulating gas inlet of the radiant waste boiler and is used to transfer a portion of the quenched crude syngas to the circulating gas inlet of the radiant waste boiler, forming a mixed gas of the quenched crude syngas and the high-temperature crude syngas generated in the gasification chamber in the radiant waste boiler, thereby reducing the temperature of the high-temperature crude syngas.

2. The semi-waste boiler heat recovery gasification system according to claim 1, characterized in that, It also includes a syngas scrubbing device, which is connected to the quencher and the circulating gas treatment device, and is used to scrub the crude syngas after quenching by the quencher with a scrubbing liquid in the multi-layer tray. The circulating gas treatment device is connected to the syngas scrubbing device, receives the crude syngas after scrubbing by the syngas scrubbing device, and transmits a portion of the scrubbed crude syngas to the circulating gas inlet of the radiant waste boiler.

3. The semi-waste boiler heat recovery gasification system according to claim 1 or 2, characterized in that, The circulating gas treatment device includes a compression device for pressurizing the crude syngas output to the circulating gas inlet of the radiant waste boiler, and outputting the pressurized crude syngas to the circulating gas inlet of the radiant waste boiler.

4. The semi-waste boiler heat recovery gasification system according to claim 3, characterized in that, The circulating gas treatment device is also used to regulate the temperature of the crude syngas.

5. The semi-waste boiler heat recovery gasification system according to any one of claims 1-4, characterized in that, The quencher is provided with a slag and water outlet at the bottom for discharging wastewater that meets the first condition and recycling wastewater that meets the second condition back into the quencher.

6. The semi-waste boiler heat recovery gasification system according to claim 5, characterized in that, The crude syngas includes one or more of fly ash, CO and H2, and HCl, wherein the first condition includes a concentration threshold for HCl.

7. The semi-waste boiler heat recovery gasification system according to any one of claims 1-6, characterized in that, The gasification chamber includes a top-mounted burner for injecting the biomass and the oxidant into the gasification chamber.

8. A method for semi-waste boiler heat recovery gasification using a semi-waste boiler heat recovery gasification system according to any one of claims 1-7, characterized in that, include: The gasification chamber is used to gasify the mixed biomass and oxidant to generate the high-temperature crude syngas and the liquid slag. The liquid molten slag is output to the slag pool chamber through the lower pipe of the radiant waste boiler; The high-temperature crude syngas is output to the quencher through the gas outlet of the radiant waste boiler; The high-temperature crude synthesis gas is quenched and filtered by the quenching liquid in the quencher, and the crude synthesis gas is output through the pipe outlet above the quenching liquid. A portion of the quenched crude syngas is transferred to the circulating gas inlet of the radiant waste boiler, forming a mixed gas of the quenched crude syngas and the high-temperature crude syngas generated in the gasification chamber within the radiant waste boiler, thereby reducing the temperature of the high-temperature crude syngas.

9. The semi-waste boiler heat recovery gasification method according to claim 8, characterized in that, Also includes: The crude syngas output to the circulating gas inlet of the radiant waste boiler is pressurized.

10. The semi-waste boiler heat recovery gasification method according to claim 8 or 9, characterized in that, Also includes: The biomass and the oxidant are injected into the gasification chamber through a top-mounted burner.

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