Process method and process equipment for preparing crude synthesis gas from low-calorific-value material

Abstract

The invention discloses a process and equipment for preparing crude synthesis gas from a low-calorific-value material. The process comprises a gasification process, a dust removal process, a cooling process and a temperature control, fluidization and temperature regulation process, coal gas is used as combustion-supporting gas in the gasification process; the gasifying agent is a mixture of oxygen and steam, and the steam is superheated steam at 280 DEG C; the raw materials are gasified under the action of the gasifying agent; part of the hot coal gas after the dust removal process and part of the cold coal gas after the cooling process are pressurized by a booster fan and conveyed back into the gasification furnace; a booster fan provides power for combustion-supporting gas, and the temperature control combustion-supporting system conducts accurate control and adjustment through a temperature sensor in the gasification furnace, a hot coal gas electric adjusting valve and a cold coal gas electric adjusting valve. The bottleneck of the traditional process technology is successfully broken through, and the technical breakthrough in the aspects of gasification reaction efficiency, effective gas content, process stability under the working condition of low steam / oxygen ratio and the like is realized.

Description

Technical Field

[0001] This invention belongs to the field of chemical technology and relates to a process method and equipment for preparing crude syngas from low-calorific-value materials. In particular, it relates to a gasification process and equipment for producing crude syngas from low-quality coal, coal powder, coal gangue, and red mud as raw materials. It is especially suitable for fluidized bed gasification operations using low-calorific-value raw materials such as low-quality coal, coal powder, coal gangue, and red mud as the main raw materials. Background Technology

[0002] In the chemical industry, raw coal can be converted and utilized through various processes such as fixed-bed gasification, entrained gasification, and fluidized-bed gasification. Among these, fluidized-bed gasification, using low-rank coal as the core raw material, has become a key development direction in the field of low-rank coal gasification due to its outstanding advantages of high efficiency and cleanliness. Meanwhile, pure oxygen gasification technology, which uses pure oxygen and steam as gasifying agents to convert low-quality coal, fly ash, coal gangue, red mud, and other raw materials into mixed coal gas, is a core branch of technological evolution within the fluidized-bed gasification process system.

[0003] As is well known, raw materials such as low-quality coal, fly ash, coal gangue, and red mud have low calorific value and fluctuating calorific value. Due to the change in the properties of the raw materials, the material flow is insufficient. Therefore, there are many unsolved technical problems in preparing crude syngas (CO+H2) from raw materials such as low-quality coal, fly ash, coal gangue, and red mud. The first technical challenge is that the low calorific value of the raw materials leads to low gasification reaction efficiency and insufficient effective gas content in the output. The second technical challenge is that the calorific value of the raw materials is prone to fluctuation, which directly results in poor process stability and makes it difficult to maintain stable production.

[0004] The existing fluidized bed gasification process includes a first gasification step, a second dust removal step, and a third cooling step. The gasification equipment includes a gasifier, a screw feeder, and gasifying agent nozzles. The raw material is conveyed to the gasifier via the screw feeder. The height of the dense phase section in the boiling zone is 1-2 meters, and the operating resistance of the material bed is less than 9 kPa. When using pure oxygen as the gasifying agent, to improve the gasification reaction efficiency, increase the effective gas yield, and ensure the fluidization power of the material, approximately 160℃ saturated steam or superheated steam needs to be introduced into the fluidized bed. Currently, in typical process designs, the steam / oxygen ratio is mostly 2:1 or 3.2:1 (i.e., steam consumption is 2-3.2 kg / N). (m³ oxygen), the vaporizing agent nozzles include an upper vaporizing agent nozzle in the fine phase zone with a diameter of 65mm and a lower vaporizing agent nozzle with a diameter of 200mm; the flow velocity of the upper vaporizing agent nozzle is 60m / s~100m / s, and the flow velocity of the lower vaporizing agent nozzle is 50m / s~70m / s; however, production practice shows that excessive steam consumption will not only cause a large amount of energy loss, but also significantly restrict the improvement of effective gas production.

[0005] Engineers in this field have attempted to reduce steam consumption by lowering the steam / oxygen ratio while simultaneously increasing the saturated steam temperature, hoping to achieve significant energy savings while avoiding slagging in the boiling zone. However, as steam consumption decreases and the steam / oxygen ratio drops, new and challenging problems arise: firstly, the fluidization dynamics in the boiling zone weaken, and there is a lack of effective control measures when the boiling zone temperature rises abnormally; secondly, the diameter and flow rate of the original boiling zone nozzles are no longer compatible with the reduced steam volume, affecting the boiling effect; and there is a bottleneck in reducing the steam / oxygen ratio.

[0006] How to reduce the consumption of raw coal and use low-quality coal, fly ash, coal gangue, and red mud to replace raw coal in the preparation of crude syngas CO+H2, and explore and develop an innovative CO+H2 gasification process and device with stable process, high reaction efficiency, high yield of effective gas, and low energy consumption, has always been a difficult problem in this field.

[0007] Engineers in this field have been dedicated to finding solutions to key challenges that urgently need to be addressed, such as low gasification reaction efficiency, low yield of effective gas, poor process stability, and reduced energy consumption.

[0008] In particular, due to the fluctuation of the calorific value of the raw materials, it is difficult to ensure that the reaction temperature of the material bed is stable within the optimal range, resulting in poor stability of fluidized bed operation, and there has been no solution. Summary of the Invention

[0009] This invention discloses a process method and equipment for preparing crude syngas (CO+H2) from low-calorific-value materials, in order to solve the problems of low gasification reaction efficiency, low yield of effective gas, high energy loss, and poor process stability in the prior art.

[0010] This invention provides a process for preparing crude syngas (CO+H2) from low-calorific-value materials, employing the following technical solutions: The raw materials are low-quality coal, fly ash, coal gangue, red mud and other low-calorific-value materials. The gasifying agent is a mixture of steam and oxygen. The process includes a first gasification step, a second dust removal step, a third cooling step, and a fourth temperature-controlled fluidization adjustment step. After the raw materials enter the gasifier, they undergo a gasification reaction under the action of the gasifying agent to generate crude coal gas with CO+H2 as the main components. The crude coal gas enters the second dust removal step and the third cooling step. After the cooling step, the product coal gas CO+H2 is output through the product output channel. The fourth step, temperature-controlled fluidization adjustment process, is equipped with a reforming fluidization temperature control system, including a temperature sensor, hot gas regulating valve, cold gas regulating valve, composite gas nozzle self-regulating valve, pressurizing fan, gas pipeline, and fluidization temperature-controlled gas nozzles. The gas used in the fourth step's fluidization temperature-controlled gas nozzles originates from the hot gas output after the second step's dust removal process and the cold gas output after the third step's cooling process. The temperature sensor transmits the gasification furnace temperature from the gasification process to the control system. The hot gas output from the dust removal process passes through the hot gas regulating valve, and the cold gas output from the cooling process passes through the cold gas regulating valve. The hot gas from the hot gas regulating valve outlet and the cold gas from the cold gas regulating valve outlet are collected and mixed. The mixed gas mainly consists of CO + H2, accounting for approximately 75%, with the remainder being CO2, SO2, H2S, etc., and a calorific value of approximately 2400 kcal / Nm³. 3 The operating system, based on temperature sensor data and parameter settings, controls and adjusts the valve openings of the hot gas regulating valve and the cold gas regulating valve, regulating the mixing temperature of the hot and cold gas to 40℃~150℃. The combined hot and cold gas is pressurized to 30kPa by a pressurizing fan, with a flow rate of 5000~6000Nm³ / h. The pressurized gas is then sequentially fed back into the gasifier of the gasification process through the fluidized bed combustion pipeline, the self-regulating valve of the composite gas nozzle, and the fluidized bed gas nozzle. The operating system controls and adjusts the valve opening of the self-regulating valve of the composite gas nozzle, regulating the flow rate of the fluidized bed gas nozzle to be stable at 40~60m / s. The gasification bed temperature of the gasification process is controlled at 960~1200℃. This gasification bed temperature setting mainly depends on the melting characteristics of the raw coal ash.

[0011] The fourth step is the temperature-controlled fluidization adjustment process. The reforming fluidization temperature control system in this process addresses the calorific value fluctuations of low-calorific-value raw materials such as low-quality coal, coal gangue, and red mud by introducing mixed gas through fluidization temperature control gas nozzles to quickly compensate for the heat deficit, ensuring the bed reaction temperature remains stable within a favorable range and broadening the range of raw material compatibility. Simultaneously, the reforming fluidization temperature control system feeds back pressurized gas containing a mixture of hot and cold gases to the gasifier, supplementing the fluidization medium, enhancing the suspension and boiling state of the bed material, compensating for insufficient fluidization power under low steam / gas ratios, and ensuring the stability of fluidized operation. Furthermore, precise temperature control is achieved through temperature sensors, electric regulating valves for hot and cold gas inside the gasifier. This precise control of the reaction temperature within the furnace avoids problems such as localized high-temperature slagging or excessively low reaction temperatures, providing an effective means for temperature and resistance adjustment in the dense phase section of the boiling zone.

[0012] This invention is an optimized solution for a process of preparing crude syngas (CO+H2) from low-calorific-value materials: The gasifying agent is a mixture of oxygen and steam in a certain proportion; the steam in the gasifying agent is superheated steam at 280-500℃; the steam / oxygen ratio is in the range of 1:1 to 0.3:1, and the steam / oxygen ratio is reduced from 2:1 to 1:1 or even 0.5:1 or 0.3:1, which achieves significant energy saving in system operation.

[0013] This invention discloses a process for preparing crude syngas (CO+H2) from low-calorific-value materials, the specific steps of which are as follows: The bed temperature inside the gasifier is controlled at 960–1200℃, and the height of the dense phase section of the fluidized bed is 2–3 meters. The operating resistance of the dense phase section is less than or equal to 18 kPa. During fluidization, the height of the dense phase section of the fuel bed is increased from 1–2 meters to 2–3 meters, and the operating resistance of the material bed is increased from less than 9 kPa to less than or equal to 18 kPa, which significantly improves the mixing effect and reaction time of the bed material and enhances the reaction efficiency. This also keeps the ash and residual carbon content in the slag discharged from the bottom of the furnace below 3%, achieving efficient utilization of raw materials.

[0014] This invention discloses a process equipment for preparing crude syngas (CO+H2) from low-calorific-value materials, comprising a first-step gasification process equipment, a second-step dust removal process equipment, a third-step cooling process equipment, and a fourth-step temperature-controlled fluidization adjustment process equipment. The gasification process equipment includes a gasifier, a screw feeder, and a gasifying agent nozzle. The top of the gasifier is the crude gas outlet; the bottom is the waste outlet. Raw materials enter the gasifier via the screw feeder; a gasifying agent consisting of a mixture of steam and oxygen enters the gasifier via the gasifying agent nozzle. The crude gas outlet at the top of the gasifier is connected by pipelines to the second-step dust removal process equipment and the third-step cooling process equipment, forming the crude syngas (CO+H2) process output channel. The temperature-controlled fluidization adjustment process equipment is a reforming fluidization temperature control system, including a temperature sensor, an operating system, a hot gas regulating valve, a cold gas regulating valve, a pressurizing fan, gas pipelines, a composite gas nozzle self-regulating valve, and a fluidization temperature-controlled gas nozzle. The hot gas regulating valve is connected to the product outlet pipeline of the second-step dust removal process equipment; the cold gas... The regulating valve is connected to the outlet pipeline of the equipment in the third cooling process; the hot gas regulating valve and the cold gas regulating valve are connected to the inlet pipeline of the pressurizing fan; the outlet of the pressurizing fan is connected to the inlet pipeline of the self-controlled regulating valve of the composite gas nozzle; the outlet of the self-controlled regulating valve of the composite gas nozzle is connected to the pipeline of the fluidized temperature-regulating gas nozzle; the temperature sensor is fixedly installed on the inner wall of the refractory layer of the gasifier, and the temperature sensor is connected to the operating system, and the temperature sensor data is uploaded to the operating system; the operating system is electrically connected to the hot gas regulating valve, the cold gas regulating valve, and the self-controlled regulating valve of the composite gas nozzle; the hot gas regulating valve, the cold gas regulating valve, the pressurizing fan, the gas pipeline, the self-controlled regulating valve of the composite gas nozzle, and the fluidized temperature-regulating gas nozzle together constitute the auxiliary fluidization and temperature regulation channel; the operating system controls and regulates the valve opening size of the hot gas regulating valve and the cold gas regulating valve according to the temperature sensor information and parameter settings, and regulates the mixing temperature of the hot gas and cold gas; and controls and regulates the valve opening size of the self-controlled regulating valve of the composite gas nozzle.

[0015] This invention is an optimized solution for the process equipment for preparing crude syngas (CO+H2) from low-calorific-value materials: the gasifying agent nozzles of the first-step gasification process equipment include an upper gasifying agent nozzle and a lower gasifying agent nozzle; the upper gasifying agent nozzle is installed in the fine phase zone of the gasifier furnace; the lower gasifying agent nozzle is installed in the high-temperature reaction zone of the gasifier furnace, i.e., below the boiling zone; the height distance between the upper and lower gasifying agent nozzles is greater than or equal to 4 meters; both the upper and lower gasifying agent nozzles are circumferentially evenly distributed; the number of fluidizing temperature-regulating gas nozzles is greater than or equal to 3; the fluidizing temperature-regulating gas nozzles and the lower gasifying agent nozzles are at the same elevation angle and tangent, and the fluidizing temperature-regulating gas nozzles are circumferentially evenly distributed between the gaps of the lower gasifying agent nozzles, and the fluidizing temperature-regulating gas nozzles and the lower gasifying agent nozzles are staggered and arranged on the same plane of the gasifier inner wall.

[0016] The gasifying agent sprayed from the gasifying agent nozzle and the gas sprayed from the fluidizing temperature-regulating gas nozzle both enter the gasifier, maintaining the raw material in a suspended boiling state. The fluidizing temperature-regulating gas nozzle and the lower layer gasifying agent nozzle are arranged and installed at the same horizontal position in the high-temperature reaction zone of the furnace. This not only compensates for the insufficient fluidization power when the gas-to-steam ratio is reduced and low-calorific-value raw materials are gasified, ensuring the stability of fluidized operation, but also has a temperature regulation function, which can quickly compensate for the heat gap and ensure that the reaction temperature of the material bed is stable within a good range. This ensures that the temperature-regulating medium quickly contacts the bed material and plays its role, precisely meeting the process requirements of "real-time response and precise adjustment".

[0017] This invention is an optimized solution for the process equipment of preparing crude syngas (CO+H2) from low-calorific-value materials: the diameter of the upper gasifying agent nozzle is 25mm-50mm, and the diameter of the lower gasifying agent nozzle is 125mm-150mm. By reducing the diameter of the gasifying agent nozzle, the flow rate of the gasifying agent is appropriately increased, with the flow rate of the upper gasifying agent nozzle being 60m / s to 100m / s and the flow rate of the lower gasifying agent nozzle being 50m / s to 70m / s. Through optimization of the steam / oxygen ratio and gasifying agent nozzle parameters, the flow rate of the gasifying agent is significantly improved. The gasifying agent not only participates in the gasification reaction but also has a fluidizing effect. The gasifying agent sprayed from the gasifying agent nozzle boils the material, improving the material flow dynamics and reaction efficiency. At the same time, it ensures that the nozzle does not coke or slag.

[0018] This invention discloses a process equipment for preparing crude syngas (CO+H2) from low-calorific-value materials: the second-step dust removal equipment includes a reflux cyclone separator, a primary low-temperature cyclone separator, a secondary low-temperature cyclone separator, and a bag filter; the third-step cooling equipment includes a waste heat boiler and a scrubbing tower. The gasifier, reflux cyclone separator, waste heat boiler, primary low-temperature cyclone separator, secondary low-temperature cyclone separator, and bag filter are sequentially connected by pipelines; the outlet of the bag filter is connected to the inlet pipeline of the scrubbing tower; the hot gas regulating valve is connected to the outlet pipeline of the bag filter; and the cold gas regulating valve is connected to the outlet pipeline of the scrubbing tower. The gas, after preliminary separation by the reflux cyclone separator, is sequentially fed into the primary low-temperature cyclone separator, the secondary low-temperature cyclone separator, and the bag filter for deep treatment, efficiently removing dust impurities from the gas; the gas after dust removal by the bag filter enters the scrubbing tower for cooling, laying the foundation for subsequent processes.

[0019] This invention is an optimized solution for the process equipment for preparing crude syngas (CO+H2) from low-calorific-value materials: the bottom of the reflux cyclone separator is connected to the high-temperature reaction zone of the gasifier furnace by a reflux pipe; after the crude gas is discharged from the top outlet of the gasifier, it enters the reflux cyclone separator tangentially along the side to complete gas-solid separation. The unreacted material after separation is returned to the bottom of the gasifier through the reflux pipe and re-enters the high-temperature reaction zone for re-gasification, realizing the recycling of the incompletely reacted material.

[0020] This invention is an optimized solution for the process equipment for preparing crude syngas (CO+H2) from low-calorific-value materials: it is equipped with a high-efficiency reflux cyclone separator, which can be used in single or three-unit parallel connection, greatly improving the dust removal accuracy of the separator; based on the total ash content entering the reflux cyclone separator, the goal is to increase the dust removal rate from the original design of only 50-70% to 90%; and effectively reduce the residual carbon content in the ash carried by the crude gas.

[0021] This invention achieves efficient material conversion through reflux circulation and overcomes the problem of inefficient dust removal by using parallel high-efficiency reflux cyclone separators, thereby simultaneously improving material utilization and the quality of crude syngas.

[0022] The working process of this invention: Raw materials are fed into the fluidized bed gasifier via a screw feeder. The top of the gasifier is the crude gas outlet, which is connected to the reflux cyclone separator pipeline. The crude gas passes sequentially through a waste heat boiler, a primary low-temperature cyclone separator, a secondary low-temperature cyclone separator, and a bag filter. The top of the bag filter is connected to the bottom of the scrubbing tower pipeline, from which the prepared crude syngas (CO+H2) is output. The bottom of the reflux cyclone separator has a reflux pipe, which is connected to the bottom of the gasifier pipeline. The residual carbon in the incompletely reacted coal ash is sent back into the gasifier for a second gasification reaction. The ash after dust removal by the bag filter is sent to a collection tank and periodically discharged to an external power boiler for co-firing and reuse. The bottom of the gasifier is the slag discharge port, through which waste slag is discharged.

[0023] Part of the cooled coal gas from the scrubbing tower is mixed with part of the hot coal gas from the bag filter. The mixture is then pressurized by a booster fan to a pressure of 20–30 kPa. After being pressurized to 30 kPa, the mixture is transported through a fluidized and temperature-regulating combustion pipeline via a control system that adjusts the automatic regulating valve of the composite gas nozzle. The gas enters the gasifier through an auxiliary fluidization and temperature regulation channel formed by the fluidized and temperature-regulating gas nozzle. The air volume is 5000–6000 Nm³ / h, and the nozzle flow velocity is stable at 40–60 m / s. Through innovative design, three core breakthroughs are achieved: First, precise real-time temperature control: The injection volume of medium gas can be flexibly adjusted according to the real-time status of the gasification reaction, precisely controlling the reaction temperature of materials in the furnace, significantly improving the accuracy of furnace temperature control, and effectively avoiding industry challenges such as local high-temperature slagging or insufficient reaction; Second, optimized reaction conditions: A new and effective approach is provided for temperature and resistance adjustment in the boiling zone of the feed bed, significantly improving the mixing effect of bed materials, reaction time, and reaction efficiency; Third, efficient utilization of raw materials: Addressing the issue of calorific value fluctuations in low-calorific-value raw materials such as coal gangue, biomass, and red mud, precise temperature control and fluidization optimization ensure that the ash and residual carbon content in the bottom slag is controlled within 3%, achieving efficient conversion and utilization of low-quality raw materials. By adjusting the consumption ratio of steam and oxygen (which, after mixing, becomes the gasifying agent), the goal of reducing operating costs and increasing effective gas production capacity is achieved. Gasification reaction efficiency is enhanced, and the effective gas content is increased; process stability is ensured under low steam / gas ratio conditions.

[0024] The positive effects of this invention are as follows: It breaks through the raw material limitations of traditional gasification processes, incorporating low-calorific-value materials such as low-quality coal, solid waste coal gangue, red mud, and biomass into the raw material range, achieving resource recycling and meeting the national environmental protection and solid waste resource reuse development needs. It fundamentally solves the problems of low gasification reaction efficiency and low effective gas content in existing technologies; it also resolves the contradiction that increasing the bed temperature to improve gasification reaction efficiency leads to coking in the bed (boiling zone); it eliminates the bottleneck of reduced steam / oxygen ratio, resulting in low energy consumption; and it exhibits good process stability. By optimizing the steam / oxygen ratio and steam parameters, it reduces operating costs and improves effective gas production capacity and reaction efficiency. The newly added fluidized gas nozzle design significantly improves the accuracy of furnace temperature control and process stability, avoiding problems such as local slagging or incomplete reaction. The high-temperature separation and material backflow design of the reflux cyclone separator and the optimization of furnace bottom operating resistance enable efficient utilization of raw materials and reduce coal consumption and energy loss. The entire process and equipment are highly adaptable, broadening the range of raw material varieties that can be adapted, and can be designed according to local conditions, thus having broad application prospects. Attached Figure Description

[0025] Figure 1 This is a process flow diagram of the reforming fluidized temperature control system of the present invention; Figure 2 This is a partially enlarged view of the equipment used in the first process of this invention; Figure 3 This is a cross-sectional view of the lower gasifying agent nozzle and the fluidizing temperature-regulating gas nozzle of the present invention. In the diagram: 1. Gasifier, 2. Screw feeder, 3. Lower gasifying agent nozzle, 3a. Gasifying agent nozzle, 3b. Gasifying agent nozzle, 3c. Gasifying agent nozzle, 3d. Gasifying agent nozzle, 3e. Gasifying agent nozzle, 3f. Gasifying agent nozzle, 4. Reflux cyclone separator, 5. Waste heat boiler, 6. Reflux pipe, 7. Primary low-temperature cyclone separator, 8. Secondary low-temperature cyclone separator, 9. Bag filter, 10. Scrubber, 11. Hot gas regulating valve, 12. Cold gas regulating valve, 13. Pressurizing fan, 14. Fluidized temperature-regulating combustion aid pipeline, 15. Composite gas nozzle self-regulating valve, 16. Fluidized temperature-regulating gas nozzle, 16x. Fluidized temperature-regulating gas nozzle, 16y. Fluidized temperature-regulating gas nozzle, 16z. Fluidized temperature-regulating gas nozzle, 17. Upper gasifying agent nozzle; A. Raw material, B. Steam, C. Oxygen, D. Crude gas, E. Pressurized gas, F. Waste residue. Detailed Implementation

[0026] The present invention is further illustrated by the following embodiments, which are not intended to limit the invention in any way. Any modifications or alterations made to the present invention that are easily implemented by those skilled in the art without departing from the technical solutions of the present invention shall fall within the scope of the claims of the present invention.

[0027] The following describes three embodiments of the present invention in detail with reference to the accompanying drawings. Example 1

[0028] This invention uses low-calorific-value raw materials such as low-quality coal, fly ash, and coal gangue, as well as red mud that plays a catalytic role, as the main application objects. It uses low-quality coal, coal gangue, and red mud as inexpensive raw materials to replace raw coal and gasify them to produce CO+H2.

[0029] Example 1 of this invention: A process innovation for preparing CO+H2 gasification, targeting the characteristics of low-quality coal, coal gangue, and red mud gasification, includes a first gasification step, a second dust removal step, a third cooling step, and a fourth temperature-controlled fluidization adjustment step.

[0030] like Figure 1 , Figure 2 , Figure 3 As shown: The gasification process equipment includes a ZY fluidized bed gasifier 1, a screw feeder 2, and a gasifying agent nozzle; the raw material enters the gasifier 1 through the screw feeder 2. When boiling inside the gasifier 1, the fuel layer height is 2-3 meters, its operating resistance is less than or equal to 18 kPa, the moisture content of the raw material is controlled at 8-20%, and the calorific value is about 16-21 MJ / kg; the gasifying agent, a mixture of steam B and oxygen C, enters the gasifier 1 through the gasifying agent nozzle; the steam in the gasifying agent is superheated steam at 280℃-500℃; the steam / oxygen ratio is 1:1-0.3:1.

[0031] like Figure 1As shown: The gasifying agent nozzle includes an upper gasifying agent nozzle 17 and a lower gasifying agent nozzle 3; the upper gasifying agent nozzle 17 is installed in the fine phase zone of the gasifier 1 furnace; the lower gasifying agent nozzle 3 is installed in the high-temperature reaction zone of the gasifier 1 furnace. The height distance between the upper gasifying agent nozzle 17 and the lower gasifying agent nozzle 3 is approximately 4 to 5 meters.

[0032] like Figure 1 , Figure 2 , Figure 3 As shown: There are 3 fluidized bed temperature-regulating gas nozzles 16, including fluidized bed temperature-regulating gas nozzle 16x, fluidized bed temperature-regulating gas nozzle 16y, and fluidized bed temperature-regulating gas nozzle 16z; there are 6 lower layer gasifying agent nozzles, including gasifying agent nozzle 3a, gasifying agent nozzle 3b, gasifying agent nozzle 3c, gasifying agent nozzle 3d, gasifying agent nozzle 3e, and gasifying agent nozzle 3f; and fluidized bed temperature-regulating gas nozzles 16x, fluidized bed temperature-regulating gas nozzle 16y, and fluidized bed temperature-regulating gas nozzle 16z. The lower gasifying agent nozzles 3 are evenly distributed around the same elevation angle and tangent as the gasifying agent nozzles 3a, 3b, 3c, 3d, 3e, and 3f; the fluidizing temperature-regulating gas nozzles 16 are evenly distributed around the same circumference; and the fluidizing temperature-regulating gas nozzles 16 are evenly distributed around the gaps between the lower gasifying agent nozzles 3. The fluidizing temperature-regulating gas nozzles 16 and the lower gasifying agent nozzles 3 are arranged alternately and staggered on the inner wall of the gasifier on the same plane.

[0033] The gasifying agent sprayed from the gasifying agent nozzle and the gas sprayed from the fluidizing temperature-regulating gas nozzle both enter the gasifier, maintaining the raw material in a suspended boiling state. The fluidizing temperature-regulating gas nozzle and the lower layer gasifying agent nozzle are arranged and installed at the same horizontal position in the high-temperature reaction zone of the furnace. This not only compensates for the insufficient fluidization power when gasifying low-calorific-value raw materials and ensures the stability of fluidized operation, but also has a temperature regulation function, which can quickly compensate for the heat gap and ensure that the reaction temperature of the material bed is stable within the optimal range. This ensures that the temperature-regulating medium quickly contacts the bed material and plays its role, precisely meeting the process requirements of "real-time response and precise adjustment".

[0034] In Embodiment 1 of this invention, the upper gasifying agent nozzle diameter is 30mm, and the nozzle flow rate is increased to 80m / s. The lower gasifying agent nozzle diameter is 150mm. By reducing the nozzle diameter, the gasifying agent flow rate is moderately increased to 50-70m / s. Through optimization of the steam / oxygen ratio and gasifying agent nozzle parameters, the gasifying agent flow rate is significantly increased, which blows and boils the material, improves the material flow dynamics, and enhances the reaction efficiency. At the same time, it ensures that the nozzle does not coke or slag. The raw material undergoes a gasification reaction under the action of the gasifying agent to generate crude coal gas D, whose main components are CO + H2.

[0035] like Figure 1As shown: The second-step dust removal equipment includes a reflux cyclone separator 4, a primary low-temperature cyclone separator 7, a secondary low-temperature cyclone separator 8, and a bag filter 9; the third-step cooling equipment includes a waste heat boiler 5 and a scrubbing tower 10; the top of the gasifier 1 is the outlet for crude gas D; the crude gas outlet at the top of the gasifier 1 is connected to the top pipeline of the reflux cyclone separator 4; the crude gas D after gasification in the gasification process is discharged from the top outlet of the gasifier 1 and enters the reflux cyclone separator 4, i.e., the second-step dust removal process, and most of the fly ash returns to the gasifier through the tangential reflux pipe 6 on the side. Inside the gasifier, dust and impurities in the gas are efficiently removed, laying the foundation for subsequent processes. The gas, after initial separation by the reflux cyclone separator 4, is sequentially sent to the waste heat boiler 5, the primary low-temperature cyclone separator 7, the secondary low-temperature cyclone separator 8, and the bag filter 9 for further treatment. The top of the bag filter is connected to the bottom of the scrubbing tower via a pipeline. The gas, after being dusted by the bag filter 9, enters the scrubbing tower 10 for cooling. The synthesized gas (CO+H2) is then output from the outlet of the scrubbing tower 10. The lower part of the gasifier 1 is the waste residue outlet F. The waste residue is discharged through the slag discharge port.

[0036] like Figure 1 As shown: The bottom of the reflux cyclone separator 4 is connected to the bottom of the gasifier 1 via a reflux pipe 6; the residual carbon material in the incompletely reacted coal ash after separation of the crude coal gas D is sent back to the gasifier 1 through the reflux pipe 6 for another gasification reaction. The target recovery rate of the reflux cyclone separator is 95%, which significantly reduces the residual carbon content in the ash carried by the coal gas; the reflux cyclone separator 4 realizes the recycling of incompletely reacted materials. The ash after dust removal by the bag filter 9 is sent to the external device collection tank of the process unit of this invention, and then periodically discharged to the external device power boiler of the process unit of this invention for co-firing and reuse.

[0037] like Figure 1 As shown: The equipment for the fourth step of temperature control and fluidization adjustment process is a reforming fluidization temperature control system, including a fluidization temperature control gas nozzle 16, a temperature sensor, an operating system, a hot gas regulating valve 11, a cold gas regulating valve 12, a pressurizing fan 13, a fluidization temperature control combustion-supporting pipeline 14, and a composite gas nozzle self-control regulating valve 15; the gas from the fluidization temperature control gas nozzle 16 comes from the hot gas output after the second step of dust removal and the cold gas output after the third step of cooling; the hot gas regulating valve 11 is connected to the bag filter dust collector. The outlet pipeline of filter 9 is connected; the cold gas regulating valve 12 is connected to the outlet pipeline of the scrubbing tower 10; the hot gas regulating valve 11 and the cold gas regulating valve 12 are connected to the inlet pipeline of the pressurizing fan 13; part of the cold gas cooled by the scrubbing tower 10 is mixed with part of the hot gas after the bag filter 9. The main components of the mixed gas are CO + H2, the gasification reaction efficiency is greater than 80%, the effective gas content is greater than 72%, and the others are CO2, SO2, H2S, etc., with a calorific value of about 2200 kcal / Nm³. 3 ; like Figure 1As shown: the outlet of the pressurizing blower 13 is connected to the inlet pipeline of the self-controlled regulating valve 15 of the compound gas nozzle; the outlet of the self-controlled regulating valve 15 of the compound gas nozzle is connected to the pipeline of the fluidized temperature-regulating gas nozzle 16; the mixed gas is introduced into the pressurizing blower 13, and the pressurization of the pressurizing blower 13 is increased by 20-30 kPa; after being pressurized to 30 kPa, the air volume is 5000-6000 Nm³ / h; the pressurized gas E enters the gasifier 1 through the fluidized temperature-regulating combustion-supporting pipeline 14, the self-controlled regulating valve 15 of the compound gas nozzle, and the fluidized temperature-regulating gas nozzle 16; the hot gas regulating valve 11, the cold gas regulating valve 12, the pressurizing blower 13, the fluidized temperature-regulating combustion-supporting pipeline 14, the self-controlled regulating valve 15 of the compound gas nozzle, and the fluidized temperature-regulating gas nozzle 16 together constitute the auxiliary fluidization and temperature regulation channels.

[0038] A temperature sensor is fixedly installed on the inner wall of the refractory layer of gasifier 1, transmitting the gasifier's internal temperature to the control system. The operating system is electrically connected to the hot gas regulating valve 11, the cold gas regulating valve 12, and the self-regulating regulating valve 15 of the composite gas nozzle. Based on the temperature sensor's information and parameter settings, the operating system controls and adjusts the valve openings of the hot gas regulating valve 11 and the cold gas regulating valve 12, regulating the mixing temperature of the hot and cold gas. The mixed temperature of the hot and cold gas is maintained between 40℃ and 150℃. The operating system also controls and adjusts the valve opening of the self-regulating regulating valve 15 of the composite gas nozzle, regulating the flow rate and velocity of pressurized gas E entering the fluidized temperature-regulating gas nozzle 16, maintaining the flow velocity of the fluidized temperature-regulating gas nozzle 16 at a stable range of 40–60 m / s. The gasification bed temperature in the gasification process is controlled between 960 and 1010℃.

[0039] The specific operational data is shown in the table below: Table 1 Real-time Operation Data of Gasifier ; Table 2 Gasifier Operation Data .

[0040] Example 2

[0041] The connection structure of this embodiment is consistent with that of Embodiment 1. The core process parameters of the gasification process are optimized and controlled as follows: the ratio of steam to oxygen introduced into the fluidized bed is adjusted to 1:1, the height of the boiling dense phase section is controlled at 2-3m, the bed resistance is controlled within 18kPa, and the furnace temperature is maintained at 1010-1050℃; the raw coal is selected as high-quality qualified coal with a calorific value of about 21MJ / kg and dried to a moisture content of 8%. Under the above process conditions, the effective gas (CO+H2) content generated by the gasification reaction can reach 80%. If the gasifying agent flow rate is appropriately increased by reducing the diameter of the gasifying agent nozzle, and the gasifying agent flow rate is stabilized at 50-70m / s; at the same time, the steam-to-gas ratio is further reduced to 0.5:1, and the coal gasification temperature regulating nozzle is activated simultaneously, the gasification reaction efficiency is above 80%, and the effective gas (CO+H2) content is expected to increase to about 83%, achieving a significant increase in product added value. Example 3

[0042] The connection structure of this embodiment is consistent with that of Embodiment 1. The core differences lie in the process parameters and the operational status of some equipment, as detailed below: I. Setting process parameters: 1. Raw coal specifications: The moisture content of the raw coal was adjusted from the original setting of 20% to 25% and calorific value of 16 MJ / kg to 8% and 21 MJ / kg. 2. Gasifier operating parameters: The height of the dense phase section of the material bed in the gasifier is 2.5m, the material bed operating resistance is 18kPa, and the furnace temperature is adjusted to 1050~1100℃; 3. Nozzle configuration and parameters: Upper layer gasifying agent nozzle 17, diameter 32mm, quantity 24; Lower layer gasifying agent nozzle 3, diameter 150mm, quantity 6; Fluidized temperature-regulating gas nozzle 16, quantity 3.

[0043] 4. The steam / oxygen ratio of the gasifying agent is 0.439:1.

[0044] II. Implementation Results: After the above process optimization and adjustment, the effective gas (CO+H2) content is expected to increase from the original 75% to 83%. This optimization scheme has good practicality and promotion value, and can play a leading role in similar enterprises. Through implementation and verification, this invention has determined a suitable parameter range, controlling the raw material moisture content to 8%–10%, the calorific value to approximately 16–21 MJ / kg, adding three fluidized bed temperature-regulating gas nozzles, increasing the height of the dense phase section of the material bed from 1–2 meters to 2–3 meters, controlling the furnace temperature to 960–1100℃, and improving the material bed operating resistance from less than 9 kPa to less than or equal to 18 kPa. This significantly improves the mixing effect and reaction time of the bed material, thereby increasing reaction efficiency; and controls the ash residue carbon content in the bottom slag discharge to within 3%, achieving efficient utilization of raw materials.

[0045] The reforming fluidized bed temperature control system achieves precise temperature regulation through temperature sensors on the inner wall of the gasifier, electric regulating valves for hot and cold gas, and electric regulating valves for cold gas. By precisely controlling the reaction temperature inside the furnace, it avoids problems such as localized high-temperature slagging or excessively low reaction temperatures, providing an effective way to regulate the temperature and resistance of the dense phase section of the feed bed. Addressing the calorific value fluctuations of low-calorific-value raw materials such as low-quality coal, coal gangue, and red mud, the system introduces gas through fluidized bed temperature control nozzles to quickly compensate for the heat deficit, ensuring the feed bed reaction temperature remains stable within a favorable range and broadening the range of raw material compatibility. Simultaneously, it supplements the fluidizing medium, enhancing the suspension and boiling state of the bed material, compensating for insufficient fluidization power under low steam / gas ratios, and ensuring the stability of fluidized bed operation.

[0046] The technical solutions of the present invention are not limited to the specific embodiments described above. Any technical modifications made in accordance with the technical solutions of the present invention fall within the protection scope of the present invention.

Claims

1. A process for preparing crude syngas from low-calorific-value materials, wherein the raw materials are low-quality coal, fly ash, coal gangue, red mud, etc., and the gasifying agent is a mixture of steam and oxygen; the process includes a gasification step, a dust removal step, and a cooling step; the raw materials undergo a gasification reaction under the action of the gasifying agent to generate crude syngas whose main components are CO + H2; the crude syngas enters the second dust removal step and the third cooling step, and after the cooling step, the product syngas CO + H2 is output through the product output channel, characterized in that: It also includes a temperature-controlled fluidized bed adjustment process; the equipment for the temperature-controlled fluidized bed adjustment process is a reforming fluidized bed temperature control system, including a temperature sensor, a hot gas regulating valve, a cold gas regulating valve, a composite gas nozzle self-regulating valve, a pressurizing fan, a gas pipeline, and a fluidized bed temperature control gas nozzle; the gas for the fluidized bed temperature control gas nozzle in the temperature-controlled fluidized bed adjustment process comes from the hot gas output after the dust removal process and the cold gas output after the cooling process; the temperature sensor uploads the temperature inside the gasifier of the gasification process to the control system; the hot gas output from the dust removal process passes through the hot gas regulating valve, and the cold gas output from the cooling process passes through the cold gas regulating valve; the hot gas at the outlet of the hot gas regulating valve and the cold gas at the outlet of the cold gas regulating valve are collected and mixed; the operating system controls and adjusts the valve opening size of the hot gas regulating valve and the cold gas regulating valve according to the data uploaded by the temperature sensor and the parameter settings, and regulates the mixing temperature of the hot gas and cold gas to 40℃~150℃; The hot and cold coal gas are combined and pressurized to 30 kPa by a pressurizing blower, with an air volume of 5000-6000 Nm³ / h. The pressurized coal gas is then fed back into the gasifier of the gasification process through a controlled and regulated composite gas nozzle and a fluidized temperature-regulating gas nozzle. The operating system controls and regulates the valve size of the self-regulating valve of the composite gas nozzle to stabilize the nozzle flow rate at 40-60 m / s. The gasification bed temperature of the gasification process is controlled at 960-1200℃.

2. The process for preparing crude syngas according to claim 1, characterized in that: The vaporizing agent is a mixture of oxygen and steam in a certain proportion; the steam in the vaporizing agent is superheated steam at 280~500℃; the steam / oxygen ratio is in the range of 1:1~0.3:

1.

3. The process for preparing crude syngas according to claim 1, characterized in that: The bed temperature is controlled at 960~1200℃, the height of the dense phase section of the material bed is 2~3 meters, and the operating resistance of the material bed is less than or equal to 18kPa.

4. Equipment for implementing the process of preparing crude syngas as described in claim 1; comprising gasification equipment, dust removal equipment, and cooling equipment; the gasification equipment includes a gasifier, a screw feeder, and a gasifying agent nozzle; the top of the gasifier is a crude gas outlet; the bottom is a waste residue outlet; raw materials enter the gasifier through the screw feeder; a gasifying agent consisting of a mixture of steam and oxygen enters the gasifier through the gasifying agent nozzle; the crude gas outlet at the top of the gasifier is connected by pipelines to the dust removal equipment and the cooling equipment; constituting a crude syngas production channel; characterized in that: It also includes equipment for the temperature-controlled fluidization adjustment process; the equipment for the temperature-controlled fluidization adjustment process is a reforming fluidization temperature control system, including a temperature sensor, operating system, hot gas regulating valve, cold gas regulating valve, pressurizing fan, gas pipeline, composite gas nozzle self-control regulating valve, and fluidization temperature-regulating gas nozzle; the hot gas regulating valve is connected to the product outlet pipeline of the dust removal process equipment; the cold gas regulating valve is connected to the outlet pipeline of the cooling process equipment; the hot gas regulating valve and the cold gas regulating valve are connected to the inlet pipeline of the pressurizing fan; the outlet of the pressurizing fan is connected to the inlet pipeline of the composite gas nozzle self-control regulating valve; the outlet of the composite gas nozzle self-control regulating valve is connected to the fluidization temperature-regulating gas nozzle. The nozzle pipeline is connected; the temperature sensor is fixedly installed on the inner wall of the refractory layer of the gasifier, and the temperature sensor is connected to the operating system. The temperature sensor data is uploaded to the operating system; the operating system is electrically connected to the hot gas regulating valve, the cold gas regulating valve, and the compound gas nozzle self-control regulating valve; the hot gas regulating valve, the cold gas regulating valve, the pressurizing fan, the gas pipeline, the compound gas nozzle self-control regulating valve, and the fluidizing temperature regulating gas nozzle together constitute the auxiliary fluidization and temperature regulation channel; the operating system controls and adjusts the valve size of the hot gas regulating valve, the cold gas regulating valve, and the compound gas nozzle self-control regulating valve according to the data uploaded by the temperature sensor and the parameter settings.

5. The equipment for the process of preparing crude syngas according to claim 4, characterized in that: The gasifying agent nozzles in the gasification process equipment include upper gasifying agent nozzles and lower gasifying agent nozzles. The upper gasifying agent nozzles are installed in the fine phase zone of the gasifier furnace. The lower gasifying agent nozzles are installed on the lower furnace wall in the high-temperature reaction zone of the gasifier furnace, i.e., below the boiling zone. The height distance between the upper and lower gasifying agent nozzles is greater than or equal to 4 meters. Both the upper and lower gasifying agent nozzles are circumferentially evenly distributed. The number of fluidizing temperature-regulating gas nozzles is greater than or equal to 3. The fluidizing temperature-regulating gas nozzles and the lower gasifying agent nozzles are at the same elevation angle and tangent. The fluidizing temperature-regulating gas nozzles are circumferentially evenly distributed between the gaps of the lower gasifying agent nozzles. The fluidizing temperature-regulating gas nozzles and the lower gasifying agent nozzles are staggered and arranged on the same plane of the gasifier wall.

6. The equipment for the process of preparing crude syngas according to claim 4, characterized in that: The nozzle diameter for the upper vaporizing agent is 25mm~50mm, and the nozzle diameter for the lower vaporizing agent is 125mm~150mm.

7. The equipment for the process of preparing crude syngas according to claim 4, characterized in that: The dust removal equipment includes a reflux cyclone separator, a primary low-temperature cyclone separator, a secondary low-temperature cyclone separator, and a bag filter; the third-stage cooling equipment includes a waste heat boiler and a scrubbing tower; the gasifier, reflux cyclone separator, waste heat boiler, primary low-temperature cyclone separator, secondary low-temperature cyclone separator, and bag filter are connected sequentially by pipelines; the outlet of the bag filter is connected to the inlet pipeline of the scrubbing tower; the hot gas regulating valve is connected to the outlet pipeline of the bag filter; and the cold gas regulating valve is connected to the outlet pipeline of the scrubbing tower.

8. The equipment for the process of preparing crude syngas according to claim 4, characterized in that: The bottom of the reflux cyclone separator is connected to the high-temperature reaction zone of the gasifier furnace by a reflux pipeline.

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