A method for producing high-quality syngas by co-gasification of carbon dioxide with high-chlorine, high-alkali pulverized coal and biomass.

Abstract

This invention discloses a method for producing high-quality syngas through the co-gasification of high-chloride, high-alkali pulverized coal and biomass with carbon dioxide. Using high-chloride, high-alkali pulverized coal and biomass as raw materials, and CO2 as the main gasifying agent, with O2 and water vapor as auxiliary gasifying agents, a synergistic gasification reaction is carried out to achieve the coupled conversion of high-chloride, high-alkali pulverized coal, biomass, and CO2, obtaining CO-rich syngas with CO and H2 as the main components. This achieves synergistic resource utilization and emission reduction of the greenhouse gas CO2, carbon sequestration and pollution reduction, in line with the national "dual carbon" goals. Simultaneously, it is adaptable to different types of biomass raw materials and gasifier types, exhibiting good versatility and flexibility. It achieves effective complementarity of energy and resources, maximizes the utilization of the resource endowments of pulverized coal and biomass, improves energy utilization efficiency, and realizes the resource utilization of CO2.

Description

Technical Field

[0001] This invention belongs to the field of energy engineering technology, specifically relating to clean conversion of coal-based energy and carbon dioxide resource utilization technology, and particularly to a method for co-gasification of high-chlorine and high-alkali pulverized coal and biomass to produce high-quality syngas using carbon dioxide coupling. Background Technology

[0002] Coal gasification is an important technological approach for modern coal chemical industry to achieve clean and efficient utilization of coal. Xinjiang Uygur Autonomous Region and other areas are rich in coal resources, but a large amount of coal exists in pulverized coal form, which presents problems such as fine particle size, difficulty in forming, poor slurry properties, high transportation costs, and insufficient local high-value utilization. At the same time, some coal from Xinjiang Uygur Autonomous Region has characteristics such as high alkali and high chlorine, which easily leads to problems such as bed agglomeration, slagging, ash accumulation, corrosion, and downstream catalyst poisoning during the gasification process, affecting the long-term stable operation of the gasification unit.

[0003] On the other hand, the Xinjiang Uygur Autonomous Region is rich in agricultural, forestry, and forestry by-product resources, including cotton stalks, fruit tree pruning branches, and other agricultural and forestry residues. Open-air storage or incineration can easily lead to emissions of pollutants such as particulate matter, volatile organic compounds, and CO. These biomass products typically have high volatile matter content, high reactivity, and relatively low ash and sulfur / nitrogen content, but they also suffer from strong seasonality, high collection, storage, and transportation costs, high tar content from gasification alone, and large fluctuations in calorific value, limiting their large-scale and high-value utilization.

[0004] Under the constraints of the "dual carbon" target, promoting the resource utilization of CO2 is one of the important ways to reduce carbon emissions in the fossil energy conversion process, and to mitigate the impact of the greenhouse effect on human society by establishing a sustainable circular pathway. Introducing CO2 as a gasifying agent and reactant into a co-gasification system of high-chlorine, high-alkali pulverized coal and biomass can promote the conversion of carbon-containing components to CO through carbon gasification reactions (C + CO2 → 2CO) and tar / light hydrocarbon reforming, thereby achieving CO2 resource utilization while obtaining CO-rich syngas. However, existing coal and biomass co-gasification technologies mainly focus on improving carbon conversion rate, increasing gas production, or improving the calorific value of fuel gas, while paying insufficient attention to issues such as the conversion efficiency of CO2 as a reaction medium in the gasification process, the mechanism of directional CO generation, in-situ suppression and reforming of tar, and the stable operation of the unit under high-chlorine, high-alkali pulverized coal conditions. Although some technologies involve the co-gasification of coal and biomass, they have not yet systematically solved key problems such as low effective CO2 conversion rate, insufficient directional control of CO-rich syngas, limited control of tar and light organic by-products, and risks to downstream equipment caused by the migration and release of components such as Na, K, Ca, and Cl. These issues restrict the development of such technologies toward low-carbon, high-efficiency, and stable engineering.

[0005] Existing coal gasification technologies are mainly classified into fixed-bed, fluidized-bed, and entrained-flow-bed systems based on bed type. Fluidized-bed systems have advantages such as high heat and mass transfer rates, uniform temperature distribution, and good adaptability to small-particle solids, making them suitable for pulverized coal gasification. However, existing co-gasification schemes for high-chlorine and high-alkali pulverized coal and biomass are mostly implemented by adding biomass to traditional coal gasifiers. They are often customized for single or a few specific biomass feedstocks. Due to the wide range of biomass sources, diverse types, and significant differences in composition and thermal reaction characteristics (such as large fluctuations in volatile matter, ash composition, ash melting point, and alkali metal / halogen content), existing invention patents often involve customized designs for single or a few specific biomass feedstocks and limit operating parameters, resulting in insufficient feedstock adaptability and engineering versatility. Meanwhile, existing technologies typically fail to systematically consider the impact of differences in pulverized coal types (ash content and ash fusion characteristics, alkali metal / chlorine content, reactivity, etc.) on the stability of the co-gasification process, as well as the risks of slagging, corrosion, and downstream catalyst poisoning. They also lack process mechanism explanations and equipment adaptation schemes for introducing CO2 as a gasifying agent and reactant into the pulverized coal and biomass system to achieve synergistic coupling. This makes it difficult to achieve a unified approach of high carbon conversion, high CO2 conversion, and controllable syngas composition under low-carbon operating conditions. Furthermore, existing fluidized bed reactors used for co-gasification often face problems such as high tar production, bed adhesion / agglomeration, increased corrosion and slagging tendency, low process efficiency, and large emissions of CO2 and other harmful gases when handling complex feedstocks with high volatile matter and high alkali / chlorine content. These issues further limit their long-term stable operation and industrial-scale application under complex feedstock conditions. Therefore, there is an urgent need to develop a CO2 coupled co-gasification method for the synergistic utilization of high-chloride and high-alkali pulverized coal and agricultural and forestry biomass resources. By synergistically regulating the raw material ratio, gasifying agent composition and reaction conditions, the CO2 conversion rate and CO generation can be improved, tar generation can be reduced, and the stability of the gasification process of high-chloride and high-alkali raw materials can be improved. Summary of the Invention

[0006] To address the problems of existing pulverized coal and biomass co-gasification processes, such as poor raw material adaptability, high tar production, fine pulverized coal particle size, difficulty in forming, poor slurry formation, high transportation costs, weak biomass consumption capacity, low added value, high energy consumption, concentrated CO2 emissions, insufficient resource utilization, low CO selectivity in the produced gas, and the tendency for tar increase, bed agglomeration, and alkali metal migration to occur when high-alkali / high-chlorine pulverized coal is co-gasified with high-chlorine and high-alkali pulverized coal and biomass, this invention provides a method for producing high-quality syngas through carbon dioxide coupling with the co-gasification of high-chlorine and high-alkali pulverized coal and biomass, so as to achieve stable and efficient conversion and CO2 resource utilization under complex raw material conditions.

[0007] Specifically, this invention uses CO2 as the main gasifying agent and O2 and water vapor as auxiliary gasifying agents to carry out a synergistic gasification reaction, thereby achieving the coupled conversion of high-chlorine and high-alkali pulverized coal, biomass and CO2, and obtaining CO-rich syngas with CO and H2 as the main components.

[0008] This invention optimizes the type and ratio of gasification feedstock, the composition and supply method of CO2 / O2 / steam gasification agent, reaction temperature / pressure, and other operating parameters. It also adapts to different furnace types, such as pressurized bubbling circulating fluidized bed or fixed bed with POX devices, to obtain syngas with CO and H2 as the main components and an adjustable composition. This allows for adjustment of the syngas composition and H2 / CO ratio, making it suitable for various downstream processes such as methanol synthesis, ammonia synthesis, or Fischer-Tropsch synthesis. This achieves synergistic effects of CO2 resource utilization and emission reduction, carbon sequestration and pollution reduction, aligning with the national "dual carbon" goals. Furthermore, it is adaptable to different types of high-chlorine, high-alkali pulverized coal and biomass feedstocks and gasification furnace types, demonstrating good versatility and flexibility. It achieves effective energy and resource complementarity, maximizing the utilization of pulverized coal and biomass resource endowments, improving energy utilization efficiency, and realizing CO2 resource utilization. Therefore, this technology has good economic benefits and broad market prospects.

[0009] To achieve this objective, the present invention adopts the following technical solution:

[0010] This invention provides a method for producing high-quality syngas by co-gasification of carbon dioxide with high-chlorine, high-alkali pulverized coal and biomass, comprising the following steps:

[0011] (1) The high-chlorine and high-alkali pulverized coal and biomass are dried, crushed and screened respectively to obtain high-chlorine and high-alkali pulverized coal and biomass particles with a particle size of 1-10 mm;

[0012] (2) After uniformly mixing the high-chlorine and high-alkali pulverized coal and biomass from step (1) at a mass ratio of 5:5 to 9:1, feed them into the reaction device at a feed rate of 0.1 to 1.0 kg / h; at the same time, feed them into the reaction device at a feed rate of 0.1 to 1.0 Nm 3 The main gasifying agent CO2 is introduced at a flow rate of 0.05–0.80 Nm³ / h. 3 The auxiliary gasifying agent O2 is introduced at a flow rate of 0.05–0.80 kg / h, and the auxiliary gasifying agent water vapor is introduced at a feed rate of 0.05–0.80 kg / h. The gasification reaction is carried out under the conditions of pressure of 0.1–3.0 MPa and heating of 1000–1200 ℃, so as to realize the coupled conversion of high-chlorine and high-alkali pulverized coal, biomass and CO2, and produce CO-rich syngas.

[0013] Preferably, the high-chlorine and high-alkali pulverized coal in step (1) has a dry basis Cl content of >3% and a total basis Na+K content of >0.50%, or a dry basis Cl content of >3% and a sodium oxide content of Na2O+0.66K2O >3.0% in the coal ash; more preferably, it has a dry basis Cl content of >3% and a sodium oxide content of Na2O+0.66K2O >3.0% in the coal ash, i.e., high-chlorine and high-alkali pulverized coal produced in the Zhundong region of Xinjiang Uygur Autonomous Region.

[0014] Preferably, the biomass in step (1) includes agricultural and forestry by-products, and further includes at least one of cotton stalks and fruit trees.

[0015] Preferably, the drying in step (1) refers to drying at 105±5 ℃ for 12±1 h.

[0016] Preferably, the mass ratio of high-chlorine, high-alkali pulverized coal and biomass in step (2) is 7:3 to 8:2.

[0017] Preferably, the reaction apparatus in step (2) includes at least one of a pressurized bubbling circulating fluidized bed and a fixed bed with POX.

[0018] Preferably, the gasification reaction time in step (2) is 60 to 180 min.

[0019] Preferably, the reaction device in step (2) needs to be purged with an inert gas before the material is introduced, and the inert gas is nitrogen.

[0020] Preferably, a mineral regulator is added to the mixed feed of high-chloride and high-alkali pulverized coal and biomass in step (2); the mineral regulator includes kaolin; the ratio of the mass of the mineral regulator to the total mass of the mixed high-chloride and high-alkali pulverized coal and biomass is 1 to 10:100; more preferably 5:100.

[0021] (1) This invention provides a method for producing high-quality syngas by coupling high-chlorine and high-alkali pulverized coal with various types of biomass (agricultural and forestry by-products, such as cotton stalks and fruit trees) with CO2 in the Zhundong area of ​​Xinjiang Uygur Autonomous Region. This method can achieve efficient utilization of pulverized coal, biomass and CO2, improve energy conversion rate, be green and low-carbon, and reduce pollution.

[0022] (2) Pulverized coal and biomass are dried, crushed, and screened separately to ensure that their particle size (1-10 mm) meets the requirements for gasification furnace feeding. Pulverized coal and biomass are mixed according to a preset mass ratio to obtain mixed raw materials, with a pulverized coal / biomass mass ratio of approximately 7:3 or 8:2. Through the synergistic reaction of pulverized coal / biomass and the gasification-reforming process involving CO2, the efficient utilization of pulverized coal, biomass resources, and CO2 is achieved, resulting in high-quality syngas with CO as the main component and adjustable composition. This process also has engineering application advantages in reducing tar, mitigating slagging corrosion, and reducing pollutant generation.

[0023] (3) By introducing CO2, oxygen, and / or water vapor, and precisely controlling reaction conditions (such as reaction temperature, reaction pressure, and reaction time), CO2 is used as the main gasifying agent, and O2 and water vapor are used as auxiliary gasifying agents. The process is adjusted according to the heat balance and syngas composition. By controlling the ratio of CO2, oxygen, and water vapor and the total amount of gasifying agent, key process parameters such as reaction temperature (1000-1200 °C), reaction pressure (0-3 MPa), and residence time are set to ensure that the co-gasification reaction operates within a stable window. This achieves directional control of the product syngas, fully utilizes the characteristics of raw material pulverized coal / biomass, and couples multiple reaction processes such as CO2, thereby improving CO2 conversion / absorption levels while maintaining high carbon conversion rates and taking into account thermal efficiency.

[0024] (4) The mixed raw materials obtained in (2) are continuously fed into the gasifier and coupled co-gasification reaction is carried out under the conditions set in step 3, so that pulverized coal and biomass react with CO2 in the same reaction system to generate syngas; the gasifier is one of pressurized bubbling circulating fluidized bed or fixed bed with POX device, so as to adapt to different raw materials and load conditions and improve gas-solid heat and mass transfer efficiency and bed stability.

[0025] (5) The gasification product syngas is subjected to dust removal, heat exchange, separation and purification and tar control treatment. By adjusting the CO2 / oxygen / water vapor ratio, reaction temperature, reaction pressure and residence time, CO enrichment in syngas and controllable adjustment of H2 / CO molar ratio are achieved, so as to obtain a high-quality syngas product with CO as the main component and adjustable composition.

[0026] (6) The CO2 comes from externally supplied CO2 and / or from CO2-containing gas reflux recovered from inside the device. By adjusting the introduction strategy of the CO2 and the oxygen and / or water vapor, the reaction heat balance and synthesis gas composition control are achieved, wherein the introduction strategy includes one or more of continuous introduction, segmented introduction, pulsed introduction, and distributed introduction.

[0027] (7) When high-chlorine and high-alkali pulverized coal participates in the gasification reaction, bed conditioning materials are added to the reaction system to inhibit the migration, volatilization, deposition and bed agglomeration of alkali metals such as Na and K; the bed conditioning materials include at least one of kaolin, dolomite, limestone, alumina and aluminosilicate.

[0028] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0029] (1) In this invention, CO2 is introduced as the main gasifying agent into the co-gasification system of pulverized coal and biomass, so that CO2 not only exists as a fluidizing medium or dilution gas, but also participates in carbon gasification and gas phase reforming reaction, thereby improving CO2 conversion rate and CO generation.

[0030] (2) This invention uses the high volatile matter and alkaline / alkaline earth metal components of biomass to promote the coking reaction of pulverized coal and the reforming reaction of CO2 water vapor. The pulverized coal and bed system can also promote the cracking and reforming of biomass tar. The two produce a synergistic effect under the coexistence of CO2 / O2 / water vapor, realizing the synergistic high-value conversion of pulverized coal, biomass and CO2.

[0031] (3) The H2 / CO molar ratio in the synthesis gas obtained by the present invention can be adjusted, and it is flexibly applicable to the control of feed gas in downstream carbonyl synthesis, Fischer-Tropsch synthesis, methanol synthesis or other C1 chemical processes.

[0032] (4) This invention is applicable to the on-site high-value utilization of high-chlorine and high-alkali pulverized coal and agricultural and forestry biomass in areas such as Zhundong, Xinjiang Uygur Autonomous Region. It is conducive to reducing the cost of transporting pulverized coal and biomass to other regions and realizing the conversion of low-value carbon resources and the utilization of CO2 resources.

[0033] (5) When high-chlorine and high-alkali pulverized coal participates in gasification, the present invention can further combine bed control materials such as kaolin and dolomite to reduce the risk of migration and deposition of alkali metals such as Na and K, and improve the stability of the gasification process.

[0034] (6) This invention combines the utilization of pulverized coal, biomass and CO2 resources, which can achieve synergistic improvement in the high-value conversion of low-value carbon resources, CO2 consumption and utilization and high-quality syngas preparation. Attached Figure Description

[0035] Figure 1 This is a process flow diagram of the present invention.

[0036] Figure 2 This is a schematic diagram of the experimental apparatus and testing process of the present invention.

[0037] Figure 3 Comparison of CO2 conversion rates under different operating conditions.

[0038] Figure 4 Comparison chart of CO content in products under different operating conditions.

[0039] Figure 5 Comparison of product gas composition under different operating conditions. Detailed Implementation

[0040] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the implementation of the present invention is not limited thereto.

[0041] Unless otherwise specified in the embodiments of this invention, the conditions shall be performed according to conventional conditions or conditions recommended by the manufacturer. All raw materials and reagents used, unless otherwise specified, are commercially available conventional products.

[0042] Example 1

[0043] 700 g of high-chlorine, high-alkali pulverized coal from the Zhundong region of Xinjiang Uygur Autonomous Region and 300 g of cotton stalk particles were taken. The pulverized coal was dried at 105 ℃ for 12 h, then crushed and sieved to obtain particles with a diameter of 6 mm. The cotton stalks were also dried at 105 ℃ for 12 h, then crushed and sieved to obtain particles with a diameter of 6 mm. The pulverized coal and cotton stalks were mixed at a mass ratio of 7:3 and mixed in a drum mixer for 30 min to obtain a mixed raw material. An experiment was conducted using a pressurized bubbling circulating fluidized bed gasifier. After nitrogen purging for 30 min, the reactor was heated to 1100 ℃ and maintained at a stable operating temperature, and the system pressure was adjusted to 1.0 MPa.

[0044] The mixed raw materials are continuously fed into a pressurized bubbling circulating fluidized bed gasifier at a feed rate of 1.00 kg / h. The gasifying agent consists of CO2, O2, and water vapor, with a CO2 flow rate of 0.75 Nm³. 3 / h, O2 flow rate is 0.18 Nm 3 The steam feed rate was 0.20 kg / h. After the reaction started, the system was run for 30 minutes as a stabilization phase, followed by continuous stable operation for 180 minutes while data collection. The product gas, after cyclone dust removal, condensation dehydration, and tar collection, entered a gas chromatography analysis system to detect H2, CO, CO2, CH4, and hydrocarbons above C2. Tar content was determined by condensation-solvent elution / gravimetric method or according to industry standard methods.

[0045] The CO2 conversion rate during the reaction was 46.3%. The CO2 conversion rate was calculated based on the inlet and outlet CO2 molar flow rates: CO2 conversion rate = (CO2 feed molar flow rate - unreacted CO2 molar flow rate in the product gas) / CO2 feed molar flow rate × 100%. Online component analysis was performed on the gasification product gas, recording the total gas flow rate and the volume fraction of each component: H2 was 22.6 vol%, CO was 47.8 vol%, CO2 was 20.1 vol%, CH4 was 3.2 vol%, C2 and above hydrocarbons were 0.6 vol%, and the remainder were inert components. Based on the H2 and CO volume fractions, the H2 / CO molar ratio was 0.47. The gas flow rate was measured using a mass flow meter. This example demonstrates that pulverized coal and cotton stalks under CO2 / O2 / water vapor synergistic gasification conditions can significantly promote CO2 participation in the gasification reaction, increase CO2 conversion rate and CO production, and reduce tar formation.

[0046] Example 2

[0047] 800 g of high-chlorine, high-alkali pulverized coal and 200 g of fruit tree pruning branch granules from the Zhundong region of Xinjiang Uygur Autonomous Region were taken. The pulverized coal and fruit tree pruning branch granules were dried at 105 ℃ for 12 h, then crushed and sieved to obtain particles with a diameter of 6 mm. The pulverized coal and fruit tree pruning branch granules were mixed at a mass ratio of 8:2 and mixed in a drum mixer for 30 min to obtain a mixed raw material. An experiment was conducted using the same pressurized bubbling circulating fluidized bed gasifier as in Example 1. After nitrogen purging for 30 min, the reactor was heated to 1100 ℃ and maintained stable operation, with the system pressure adjusted to 1.0 MPa.

[0048] The mixed raw materials are continuously fed into a pressurized bubbling circulating fluidized bed gasifier at a feed rate of 1.00 kg / h. The gasifying agent consists of CO2, O2, and water vapor, with a CO2 flow rate of 0.75 Nm³. 3 / h, O2 flow rate is 0.18 Nm 3 The steam feed rate was 0.20 kg / h. After the reaction started, the system was run for 30 minutes as a stabilization phase, followed by continuous stable operation for 180 minutes while data was collected. The product gas treatment and analysis methods were the same as in Example 1.

[0049] The CO2 conversion rate during the reaction was 40.6%. The CO2 conversion rate was calculated based on the inlet and outlet CO2 molar flow rates: CO2 conversion rate = (CO2 feed molar flow rate - unreacted CO2 molar flow rate in the product gas) / CO2 feed molar flow rate × 100%. Online component analysis was performed on the gasification product gas, recording the total gas flow rate and the volume fraction of each component: H2 was 20.9 vol%, CO was 46.2 vol%, CO2 was 21.7 vol%, CH4 was 2.8 vol%, C2 and above hydrocarbons were 0.5 vol%, and the remainder were inert components. The H2 / CO molar ratio was 0.45. Compared with pulverized coal CO2 gasification alone, the addition of fruit tree branches in this embodiment improved the gasification reaction activity, increasing both the CO2 conversion rate and the CO production per unit feedstock, indicating a synergistic promoting effect between biomass and pulverized coal.

[0050] Example 3

[0051] 700 g of high-chloride, high-alkali pulverized coal, 200 g of cotton stalk pellets, and 100 g of fruit tree branch pellets from the Zhundong region of Xinjiang Uygur Autonomous Region were taken. All three raw materials were dried at 105 ℃ for 12 h, then crushed and sieved to obtain particles with a diameter of 6 mm. The high-chloride, high-alkali pulverized coal, cotton stalks, and fruit tree branches were mixed at a mass ratio of 7:2:1 and mixed in a drum mixer for 30 min to obtain a mixed raw material. An experiment was conducted using the same pressurized bubbling circulating fluidized bed gasifier as in Example 1. After nitrogen purging for 30 min, the reactor was heated to 1100 ℃ and maintained at a stable operating temperature, with the system pressure adjusted to 1.0 MPa.

[0052] The mixed raw materials are continuously fed into a pressurized bubbling circulating fluidized bed gasifier at a feed rate of 1.00 kg / h. The gasifying agent consists of CO2, O2, and water vapor, with a CO2 flow rate of 0.75 Nm³. 3 / h, O2 flow rate is 0.18 Nm 3 The steam feed rate was 0.20 kg / h. After the reaction started, the system was run for 30 minutes as a stabilization phase, followed by continuous stable operation for 180 minutes while data was collected. The product gas treatment and analysis methods were the same as in Example 1.

[0053] The CO2 conversion rate during the reaction was 46.6%. The CO2 conversion rate was calculated based on the inlet and outlet CO2 molar flow rates: CO2 conversion rate = (CO2 feed molar flow rate - unreacted CO2 molar flow rate in the product gas) / CO2 feed molar flow rate × 100%. Online component analysis was performed on the gasification product gas, recording the total gas flow rate and the volume fraction of each component: H2 was 21.8 vol%, CO was 49.1 vol%, CO2 was 18.8 vol%, CH4 was 2.6 vol%, hydrocarbons above C2 were 0.4 vol%, and the remainder were inert components. The H2 / CO molar ratio was 0.44.

[0054] Example 4

[0055] 700 g of high-chloride, high-alkali pulverized coal, 300 g of cotton stalk particles, and 50 g of kaolin were taken from the Zhundong region of Xinjiang Uygur Autonomous Region. The pulverized coal and cotton stalks were dried at 105 ℃ for 12 h, then crushed and sieved to obtain particles with a diameter of 6 mm. The pulverized coal, cotton stalks, and kaolin were then mixed evenly and fed into a pressurized bubbling circulating fluidized bed gasifier. Experiments were conducted using the same apparatus and conditions as in Example 1. The results showed that, compared with the system without kaolin, the addition of kaolin reduced bed agglomeration, increased the retention ratio of Na and K in the ash, and maintained a high CO content in the product gas. This indicates that the bed control material can reduce the risk of alkali metal migration and bed instability during the gasification process of high-chloride, high-alkali pulverized coal.

[0056] Comparative Example 1

[0057] 1000 g of high-chlorine, high-alkali pulverized coal from the Zhundong region of Xinjiang Uygur Autonomous Region was dried at 105 ℃ for 12 h, then crushed and sieved to obtain pulverized coal raw material with a particle size of 6 mm. An experiment was conducted using the same pressurized bubbling circulating fluidized bed gasifier as in Example 1. After nitrogen purging for 30 min, the reactor was heated to 1100 ℃ and maintained at a stable operating temperature, with the system pressure adjusted to 1.0 MPa.

[0058] Pulverized coal is continuously fed into a pressurized bubbling circulating fluidized bed gasifier at a feed rate of 1.00 kg / h. The gasifying agent consists of CO2, O2, and water vapor, with a CO2 flow rate of 0.75 Nm³. 3 / h, O2 flow rate is 0.18 Nm 3 The steam feed rate was 0.20 kg / h. After the reaction started, the system was run for 60 minutes as a stabilization phase, followed by continuous stable operation for 180 minutes while data was collected. The product gas treatment and analysis methods were the same as in Example 1.

[0059] The CO2 conversion rate during the reaction was 30.6%. The CO2 conversion rate was calculated based on the inlet and outlet CO2 molar flow rates: CO2 conversion rate = (CO2 feed molar flow rate - unreacted CO2 molar flow rate in the product gas) / CO2 feed molar flow rate × 100%. Online component analysis was performed on the gasification product gas, recording the total gas flow rate and the volume fraction of each component: H2 15.1 vol%, CO 36.42 vol%, CO2 31.4 vol%, CH4 1.9 vol%, C2 and above hydrocarbons 0.3 vol%, and the remainder being inert components. The H2 / CO molar ratio was 0.41. Compared to Example 1, the CO2 conversion rate and CO production per unit feedstock were both reduced in pulverized coal gasification alone, indicating that the addition of biomass can promote the gasification reaction between pulverized coal coke and CO2.

[0060] Comparative Example 2

[0061] 700 g of high-chlorine, high-alkali pulverized coal from the Zhundong region of Xinjiang Uygur Autonomous Region and 300 g of cotton stalk particles were taken. The pulverized coal was dried at 105 ℃ for 12 h, then crushed and sieved to obtain particles with a diameter of 6 mm. The cotton stalks were also dried at 105 ℃ for 12 h, then crushed and sieved to obtain particles with a diameter of 6 mm. The pulverized coal and cotton stalks were mixed at a mass ratio of 7:3 and mixed in a drum mixer for 30 min to obtain a mixed raw material. An experiment was conducted using a pressurized bubbling circulating fluidized bed gasifier. After nitrogen purging for 30 min, the reactor was heated to 1100 ℃ and maintained at a stable operating temperature, and the system pressure was adjusted to 1.0 MPa.

[0062] The mixed raw materials are continuously fed into a pressurized bubbling circulating fluidized bed gasifier at a feed rate of 1.00 kg / h. No CO2 is introduced; the gasifying agent consists of O2 and water vapor, with N2 used to supplement the fluidizing gas flow rate at 0.75 Nm³. 3 / h, O2 flow rate is 0.18 Nm 3 The steam feed rate was 0.20 kg / h. After the reaction started, the system was run for 30 minutes as a stabilization phase, followed by continuous stable operation for 180 minutes while data was collected. The product gas treatment and analysis methods were the same as in Example 1.

[0063] Online component analysis was performed on the gasification product gas, recording the total gas flow rate and the volume fraction of each component. The composition was: H2 24.2 vol%, CO 31.6 vol%, CO2 17.5 vol%, CH4 5.1 vol%, C2+ hydrocarbons 1.1 vol%, and the remainder being inert components. The H2 / CO molar ratio was 0.76. Compared to Example 1, without the introduction of CO2, both the CO volume fraction in the product gas and the CO production per unit feedstock decreased. This indicates that CO2 does not merely exist as a dilution or inert gas, but participates in the carbon gasification and reforming reactions, significantly increasing CO production and the quality of the CO-rich syngas.

[0064] Table 1

[0065]

[0066] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for producing high-quality syngas by co-gasification of carbon dioxide with high-chlorine, high-alkali pulverized coal and biomass, characterized in that, Includes the following steps: (1) High-chlorine and high-alkali pulverized coal and biomass are dried, crushed and screened respectively to obtain pulverized coal with a particle size of 1 to 10 mm and biomass with a particle size of 1 to 10 mm. (2) After uniformly mixing the high-chlorine and high-alkali pulverized coal and biomass from step (1) at a mass ratio of 5:5 to 9:1, feed them into the reaction device at a feed rate of 0.1 to 1.00 kg / h, and simultaneously feed them at a feed rate of 0.1 to 1.0 Nm. 3 The main gasifying agent CO2 is introduced at a flow rate of 0.05–0.80 Nm³ / h. 3 The auxiliary gasifying agent O2 is introduced at a flow rate of 0.05-0.80 kg / h, and the auxiliary gasifying agent water vapor is introduced at a feed rate of 0.05-0.80 kg / h. The gasification reaction is carried out under the conditions of 0-3.0 MPa pressure and 1000-1200℃ heating, so that the carbon gasification reaction and gas phase reforming reaction of high-chlorine and high-alkali pulverized coal, biomass and CO2 are carried out to produce CO-rich syngas.

2. The method according to claim 1, characterized in that, The high-chlorine, high-alkali pulverized coal mentioned in step (1) has a dry basis Cl content of >3% and a total basis of Na+K >0.50%, or a dry basis Cl content of >3% and a calculated sodium oxide content of Na2O+0.66K2O >3.0%; more preferably, it has a dry basis Cl content of >3% and a calculated sodium oxide content of Na2O+0.66K2O >3.0%, i.e., high-chlorine, high-alkali pulverized coal produced in the Zhundong region of Xinjiang Uygur Autonomous Region.

3. The method according to claim 1 or 2, characterized in that, The mass ratio of high-chlorine, high-alkali pulverized coal to biomass in step (2) is 7:3 to 8:

2.

4. The method according to claim 1 or 2, characterized in that, The gasification reaction in step (2) takes 60 to 180 minutes.

5. The method according to claim 1 or 2, characterized in that, The biomass mentioned in step (1) includes at least one of agricultural by-products and forestry by-products.

6. The method according to claim 5, characterized in that, The biomass mentioned in step (1) includes at least one of cotton stalks and fruit trees.

7. The method according to claim 1 or 2, characterized in that, In step (2), a mineral regulator is added to the mixed feed of high-chloride and high-alkali pulverized coal and biomass; the mineral regulator includes kaolin; the ratio of the mass of the mineral regulator to the total mass of the mixed high-chloride and high-alkali pulverized coal and biomass is 1 to 10:

100.

8. The method according to claim 1 or 2, characterized in that, The reaction apparatus in step (2) includes at least one of a pressurized bubbling circulating fluidized bed gasifier and a fixed bed POX device.

9. The method according to claim 1 or 2, characterized in that, Before introducing materials into the reaction device in step (2), an inert gas purging process is required; the inert gas is nitrogen.

10. The method according to claim 1 or 2, characterized in that, The drying step (1) refers to drying at 105±5 ℃ for 12±1 h.

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