An integrated device and process for coupling coal pyrolysis and tar hydrogenation

Abstract

This invention discloses an integrated device and process for coupling coal pyrolysis and tar hydrogenation, comprising a coal pyrolysis reactor, a tar hydrogenation reactor, and a tar collection device. By coupling these two devices and the process, energy consumption can be significantly reduced. The tar collection device improves product recovery rate, saving time and economic costs. The staggered distribution of baffles increases the mixing degree between the solid heat carrier and pulverized coal, improving the heat transfer efficiency of the fluidized bed reactor. The solid heat carrier used is iron-loaded aluminum-magnesium spinel, which not only provides heat to the pulverized coal but also provides a catalytic effect for coal pyrolysis. Furthermore, this invention is the first to propose coupling the coal pyrolysis reactor and the tar hydrogenation reactor and the process to achieve directional conversion of coal pyrolysis products, improving the quality of coal pyrolysis products and possessing significant practical value.

Description

Technical Field

[0001] This invention belongs to the technical field of chemistry and chemical engineering, specifically relating to an integrated device and process for coupling coal pyrolysis and tar hydrogenation. Background Technology

[0002] Studies show that fossil fuels will remain the foundation of the world's energy supply by 2050, with coal continuing to play a vital role. my country is rich in coal resources, with low-rank coal reserves accounting for over 55% of its total coal resources. Coal pyrolysis is the primary means of coal processing and utilization, and one of the most important clean coal technologies. However, traditional coal pyrolysis yields relatively low tar, and the tar contains high levels of heavy components that are difficult to process and utilize. Furthermore, heavy tar is highly viscous and prone to condensation, easily causing pipeline blockages and pressurization, severely hindering the high-value clean utilization of low-rank coal. Therefore, simply relying on process and equipment innovation to improve the quality of coal pyrolysis tar and solve the problem of stable plant operation is a significant challenge. Coal hydropyrolysis and coal tar hydrogenation technologies, on the other hand, can help improve the quality of pyrolysis oil and gas and achieve targeted conversion of products.

[0003] (1) Coal pyrolysis. Coal pyrolysis is the process of heating coal in the absence of air or an inert atmosphere, causing a series of complex physical changes and chemical reactions at different temperatures, thereby decomposing the coal. Pyrolysis is the first step in coal gasification, which is the thermal decomposition of organic matter under anaerobic conditions. It is an important process for the conversion and utilization of coal (Shi Junpeng, Chemical Industry, 2017, 35(6): 13-15). Coal pyrolysis involves multiple complex reactions. During coal pyrolysis, volatile substances (gases, tar) are released, leaving carbonaceous solid residues (coke). The main products obtained from coal pyrolysis are coal gas, coal tar, and semi-coke. The pyrolysis reaction of coal is related not only to the properties of the coal itself, but also to the pyrolysis temperature, heating rate, operating pressure, coal particle size, and pyrolysis atmosphere (Chen Zhaohui, University of Chinese Academy of Sciences, 2016; Li Jinze et al., Fuel and Chemical Engineering, 2020, 51(02): 8-13; Zhang Jian et al., Shandong Chemical Industry, 2016, 45(12): 56-57; Liu Zhenyu, Journal of Chemical Industry and Engineering, 2016, 67(1): 1-5). The properties of the coal itself: The quality of coal is determined by analyzing the moisture, ash, volatile matter, and fixed carbon content. The calorific value and grindability index are also used to differentiate coals. Volatile matter is a key parameter for coal classification, providing a preliminary assessment of its processing properties. Coal with high volatile matter yields higher tar and gas production during pyrolysis, while coal with low volatile matter and high fixed carbon content yields relatively higher coke production. Pyrolysis temperature and heating rate: The final temperature and heating rate of coal pyrolysis are important parameters affecting the pyrolysis reaction. The ambient temperature and the heat and mass transfer involved in coal particle size will affect the heating rate. Pyrolysis involves the breaking and condensation of chemical bonds. When the temperature is low, increasing the heating rate will result in incomplete bond breaking and less volatile matter produced, thereby reducing secondary reactions that are not conducive to the reaction and naturally increasing the yield of the reaction product tar. However, when the temperature is high, increasing the heating rate will exacerbate the occurrence of secondary reactions and result in a low coal tar yield. The final temperature and heating rate of pyrolysis together determine the distribution of pyrolysis products. The heating rate is also affected by the ambient temperature (Dun Qimeng et al., Journal of Process Engineering, 2018, 18(1): 140-147. BORAH RC et al., International Journal of Energy Research, 2011, 35: 929-96. Zhang Xiaoyang et al., Journal of Coal Science, 2019, 44(02): 604-610). Operating pressure: Operating pressure affects heat and mass transfer during the reaction process (SHUAI Cheng et al, Chinese Journal of Chemical Engineering, 2017, 25: 507-515).The high internal pressure of coal during the reaction increases the external pressure, reducing the pressure difference between the inside and outside of the coal. This increases the diffusion resistance of volatiles, making it difficult for pyrolysis products to escape, promoting secondary reactions, and reducing tar yield. The coke deposits produced by the secondary reactions block the pore structure, further reducing the diffusion of pyrolysis products (Jerzy Tomeczek et al, Fuel, 2003, 82(3): 265-292). Coal particle size: The influence of coal particle size on the pyrolysis reaction is more complex (Zhang Chun, University of Chinese Academy of Sciences, 2015). Larger particle sizes result in uneven heating of the coal, making it difficult for volatiles from the pyrolysis products to escape, leading to a decrease in the amount of tar and an increase in the amount of semi-coke. Similar to the pyrolysis under increased pressure, secondary reactions in large-particle coal are more likely to occur in the particle pore structure, reducing the amount of tar produced. At the same time, the carbon deposits after the secondary reaction block the pore structure, promoting the secondary reaction (Zhang Xu, China Coal Research Institute, 201; Chen Jinzhong et al., Guangdong Chemical Industry, 2016, 43(11): 46-47). Pyrolysis atmosphere: Different atmospheres produce different pyrolysis reaction products. The pyrolysis atmospheres generally considered include N2, H2, syngas (mainly composed of CO, CH4, CO2), and water vapor (Yang Huimin et al., Journal of Taiyuan University of Technology, 2010, 41(04): 338-34. Chen Zhaohui et al., Journal of Chemical Industry and Engineering, 2017, 68(04): 1566-157. Zhang Xiaofang et al., Journal of Chemical Industry and Engineering, 2009, 60(9): 2299-2307. Bai Zongqing et al., Journal of China University of Mining and Technology, 2011, 40. GAO S et al., Journal of Analytical & Applied Pyrolysis, 2014, 106(3): 104-111). H2 promotes the stabilization of macromolecular free radicals, enabling the hydrogenation reaction of aromatic compounds, thereby effectively inhibiting compound polymerization and increasing tar yield. Under H2 environment, coal pyrolysis involves hydrogenation cracking, including deoxygenation, demethylation, decarboxylation, and elimination of functional groups, thus slightly reducing tar yield. H2 has two completely different effects on tar yield, depending on the partial pressure of hydrogen and the degree of reaction (Zhou Guanwen, Southeast University, 2019). Pyrolysis under CH4 atmosphere produces free radical fragments, which stabilize the free radical fragments generated by the pyrolysis reaction, inhibiting polymerization reaction and improving tar yield and tar quality (Zhang Juntao et al., Journal of Coal Science and Technology, 2021, 46(01): 292-299). Under the pyrolysis atmosphere of CO, on the one hand, it can react with H2O generated by pyrolysis to generate H2, thereby affecting the pyrolysis process. On the other hand, CO can inhibit the compounds in tar from reacting again, thus enhancing the quality of tar (Liao Hongqiang et al., Journal of Fuel Chemistry, 1998, 26(1): 13-17).In pyrolysis, CO2 reacts with volatiles and semi-coke. It is generally believed that CO2 has little effect on pyrolysis, either not affecting the tar yield or reducing it (Niu Shuaixing et al., Applied Chemical Industry, 2019, 48(03): 639-645). Water vapor can penetrate the microporous structure of coal, which is beneficial to the volatilization of volatile substances in coal. At lower temperatures, water vapor can reduce the contact between tar and semi-coke, reducing secondary reactions of tar and increasing the amount of tar; high temperatures can lead to secondary reactions of tar, resulting in a decrease in tar yield (Zang Libin et al., Coal Geology and Exploration, 2020, 48(05): 34-39. HU E et al., Energy & Fuels, 2017, 31(2): 1347-1354. Lan Yushun et al., Coal Chemical Industry, 2017, 45(2): 66-71). Currently, the main coal pyrolysis technologies include hydropyrolysis, catalytic pyrolysis, methane activation pyrolysis, and coal-coke oven gas co-pyrolysis (Wu Jie et al., Coal Chemical Industry, 2019, 47(06): 46-51). The coal pyrolysis process is mainly divided into two reaction processes (Sun Zeyuan, Liaoning Chemical Industry, 2021, 50(05): 662-664). The first part is the thermal cracking of macromolecules in coal, and the volatiles after cracking react with each other. During the pyrolysis process, the coal is continuously heated, causing unstable chemical bonds such as alkyl side chains of macromolecules to break, and volatiles to escape. The second part is the condensation, cracking, dehydrogenation and hydrogenation of the products from the first part of the reaction, and the semi-coke generated is condensed into coke. From a mechanistic perspective, the coal pyrolysis process consists of three steps: initiation, transmission and termination of free radicals. First, weak chemical bonds break to form free radical intermediates, and then unstable alkyl side chains and oxygen-containing functional groups on the coal skeleton break, and some hydrogen, carbon dioxide and hydrocarbon gases begin to be released. In this process, hydrogen acts as a stabilizer and inhibitor of free radicals in the pyrolysis reaction, suppressing the condensation between free radicals and promoting their combination with hydrogen to generate small molecule volatiles. The tar obtained from coal pyrolysis technology has a high content of heavy components, making subsequent processing and extraction of coal tar difficult.

[0004] (2) Coal hydropyrolysis. Coal hydropyrolysis is a process in which coal is pyrolyzed in an H2 atmosphere to produce high-calorific-value coal gas, high-yield high-quality tar, and clean semi-coke. External hydrogen supply combines with the free radicals generated by pyrolysis to form smaller molecules with stable structures, reducing the condensation between pyrolysis free radicals. This not only helps to improve the tar yield but also promotes the lightening of heavy components. The coal hydropyrolysis reaction process can generally be divided into the following three stages (Wang Jing, Dalian University of Technology, 2007). (1) Early stage: Volatile matter is rapidly released, and the main component is tar. External hydrogen source diffuses into the coal particles, and H free radicals react with free radicals in the condensed phase in the pores of the coal particles, increasing the amount of volatile matter released. (2) Middle stage: Tar free radicals in the volatile matter react with H free radicals provided by the external hydrogen source on the surface of the coal particles to generate small molecule volatile matter, avoiding the occurrence of secondary polymerization reactions of large molecules. Due to the presence of a large number of H free radicals, there will be a degradation reaction from fused ring to monocyclic ring, as well as the removal reaction of various alkyl substituents such as phenolic hydroxyl groups. (3) Later stage: After a large amount of volatiles (mainly tar and gas) are released, H free radicals react with the active components in the residual semi-coke to generate methane. This reaction is relatively slow. Li Wen et al. (Li Wen et al., Journal of Fuel Chemistry, 1996(4): 341-347). The study found that compared with pyrolysis under N2 atmosphere, in the process of hydrogenation pyrolysis, the free radicals generated by the coal powder itself are reduced and saturated, thereby inhibiting the combination of free radicals in the reaction process, achieving the purpose of tar lightening. In this reaction process, more low molecular weight compounds are generated, which increases the tar yield. Chen Rui (Chen Rui, Beijing: Tsinghua University, 2015). The fixed bed hydrogenation pyrolysis of Shuicheng lignite was studied. The study showed that hydrogenation changed the secondary reaction process and promoted the generation of tar. With the increase of hydrogen concentration, the content of BTX and PCX in tar increased. Zhou Qixiong et al. (Zhou Qixiong et al., Coal Conversion, 2014, 37(2): 21-24). The effects of iron-based catalysts such as ferric nitrate, ferric chloride and ferrous ammonium sulfate on the characteristics of coal hydropyrolysis were studied. The results showed that iron-based catalysts improved the conversion rate of coal hydropyrolysis. Different valence states of iron had different catalytic effects on coal hydropyrolysis. Ferrous ammonium sulfate not only improved the coal pyrolysis conversion rate and tar yield, but also improved the tar quality. He Zhibao (He Zhibao, Dalian: Dalian University of Technology, 2016). Hydropyrolysis of Shenfu coal was studied. The results showed that the addition of hydrogen significantly improved the yield and conversion rate of pyrolysis products. The dry basis tar yield increased from 9.0% at 550℃ to 11.46% at 750℃. The addition of catalysts can increase the utilization rate of hydrogen and further improve the yield of light oil. In summary, coal hydropyrolysis can improve the yield of coal pyrolysis tar and the content of light components to a certain extent, but there are problems such as the difficulty in recovering the catalyst used.

[0005] (3) Coal tar hydrogenation. Coal tar hydrogenation technology (Cui Yuhong, Coal Processing and Comprehensive Utilization, 2021(07): 58-61). It refers to the technology of removing impurities such as metals, sulfur, nitrogen, and oxygen from coal tar by adding hydrogen under high temperature and high pressure conditions through the action of a catalyst, while hydrogenating and opening the chains of olefins and aromatic compounds in the components, so as to lighten the coal tar and process high-quality gasoline, diesel and other fractions. Since coal tar contains polycyclic aromatic hydrocarbons, olefins, nitrogen-containing heterocyclic compounds, sulfur-containing heterocyclic compounds, phenolic compounds and metal elements, the chemical reaction of coal tar hydrogenation is relatively complex. The main reactions of coal tar hydrogenation include hydrodesulfurization reaction, hydrodenitrogenation reaction, hydrodeoxygenation reaction and hydrodemetallization reaction, as well as the hydrogenation saturation reaction of olefins and aromatic hydrocarbons (mainly polycyclic aromatic hydrocarbons); in addition, there are also ring-opening, chain-breaking and condensation reactions. Through hydrogenation, the C-S, C-N, and C-O bonds in the coal tar molecule break, and the heteroatoms sulfur, nitrogen, and oxygen are converted into hydrogen sulfide, ammonia, and water, respectively; metal compounds are converted into metal sulfides. Because the aromatic nuclei of aromatic hydrocarbons are very stable, it is difficult to directly break the rings. Large fused-ring and polycyclic aromatic hydrocarbons can only open their rings after the aromatic rings are hydrogenated to saturation, and then undergo further cracking reactions. Generally, hydrogenation saturation of the first aromatic ring in fused-ring aromatic hydrocarbons is relatively easy, with the difficulty of hydrogenation saturation of subsequent aromatic rings increasing sequentially, and the hydrogenation saturation of the last remaining aromatic ring being the most difficult, with a reaction rate close to that of benzene. Coal tar olefins are extremely unstable and readily react with hydrogen to produce alkanes, a strongly exothermic reaction. Generally, the rates of the above-mentioned reactions, in descending order of magnitude, are as follows: diene saturation > desulfurization > deoxygenation > mono-olefin saturation > denitrogenation > aromatic saturation (Ma Baoqi et al., Beijing: Chemical Industry Press, 2010). In the process of coal tar hydrogenation, in addition to the above-mentioned hydrogenation reaction, there is also a reverse reaction, namely the condensation coking reaction. The generated coke will be deposited on the catalyst particles, which can easily cause catalyst poisoning and deactivation. In the process of coal tar hydrogenation, reaction temperature, reaction pressure, space velocity and hydrogen / oil ratio are relatively critical process parameters, which have an important impact on the composition and distribution of the product. From a kinetic point of view, increasing the reaction temperature can accelerate the reaction rate. Since hydrodesulfurization, denitrification and deoxygenation are irreversible reactions, increasing the reaction temperature is beneficial to the removal of heteroatoms such as sulfur, nitrogen and oxygen, making the generated oil cleaner. Generally, for every 10°C increase in reaction temperature, the hydrocracking reaction rate will approximately double, increasing the proportion of light components in the generated oil; however, excessively high temperature will lead to over-cracking reaction, accelerate catalyst coking, and also reduce the liquid phase yield of the product. Li Dong et al. (Li Dong et al., Coal Conversion, 2009, 34(4): 81-84). Using medium- and low-temperature coal tar from northern Shaanxi as raw material, the effects of different reaction temperatures on the hydrorefining of coal tar were investigated. It was found that increasing the reaction temperature reduced the density, nitrogen content, sulfur content, and residual carbon of the resulting oil, but the hydrogen / carbon atomic ratio showed a trend of first increasing and then decreasing.Since hydrogenation is a process in which the volume of materials decreases, increasing the reaction pressure (hydrogen partial pressure) is beneficial to the hydrogenation reaction. It is also beneficial to the removal of heteroatoms such as sulfur, nitrogen, and oxygen, inhibiting condensation and coking reactions, and reducing catalyst coking. Yan Bingfeng, Xia Liangyan, Hu Yiwen, and others found (Yan Bingfeng et al., Coal Conversion, 2019, 42(3): 18-26. Xia Liangyan et al., Journal of Zhejiang University (Engineering Science), 2015, 49(3): 578-58. Hu Yiwen et al., Acta Petrolei Sinica (Petroleum Processing), 2015, 31(1): 7-17). The hydrogenation of polycyclic aromatic hydrocarbons in coal tar mainly proceeds through ring-by-ring hydrogenation reactions to generate hydrogenated aromatic hydrocarbons, while some ring-opening and isomerization reactions also occur. Increasing the reaction pressure is beneficial for the conversion of polycyclic aromatic hydrocarbons (PAHs) to monocyclic aromatic hydrocarbons (MOHs). The difficulty of hydrogenation increases with each ring. However, since hydrogenation saturation is an exothermic reaction, the hydrogenation depth of PAHs is also limited by thermodynamic equilibrium. Space velocity determines the residence time of coal tar in the reactor. The lower the space velocity, the longer the residence time of coal tar in the reactor, and the removal rates of sulfur, nitrogen, oxygen, residual carbon and metals will increase, and the hydrogenation depth will also increase. Li Bin (Li Bin et al., Chemical Industry Progress, 2012, 31(5): 1023-1027). Studies have found that when the liquid volume hourly space velocity (LHSV) decreases, the contact time between the material and the catalyst bed increases, which will deepen the cracking degree of coal tar and help improve the hydrogenation conversion rate; however, when the LHSV drops to 0.3 h⁻¹, the influence of space velocity on the hydrocracking rate weakens. Hu Fating (Hu Fating, Clean Coal Technology, 2018, 24(2): 96-101). Studies have found that increasing the hydrogen / oil volume ratio from 500 to 800 increases the nitrogen removal rate in coal tar by 12%, while further increases in the hydrogen / oil volume ratio have little effect on the nitrogen removal rate. However, the hydrogen / oil volume ratio has a significant impact on aromatic saturation; the higher the hydrogen / oil volume ratio, the higher the content of saturated hydrocarbons in the product. This is because increasing the hydrogen / oil volume ratio leads to an increase in hydrogen partial pressure, increasing the number of hydrogen molecules participating in the coal tar hydrogenation reaction, which is beneficial for aromatic saturation. It is believed that the hydrogenation effect is best when the hydrogen / oil volume ratio is between 1500 and 2500. Significant progress has been made in the research and development of coal tar hydrogenation technology over the past 20 years, with various coal tar hydrogenation technologies developed, some of which have been industrialized. Based on the characteristics of existing technologies and reactor types, existing coal tar hydrogenation technologies can be divided into four categories: fixed-bed hydrogenation technology, delayed coking-fixed-bed hydrogenation technology, suspended-bed-fixed-bed hydrogenation technology, and fluidized-bed-fixed-bed hydrogenation technology. Fixed-bed hydrogenation technology is one of the most commonly used coal tar hydrogenation technologies, including two types: hydrorefining technology and hydrorefining-hydrocracking combined technology (Li Qinghua et al., Chinese Patent: CN1903994, 2006-08-03; Zhang Yuying et al., Chinese Patent: CN101307527, 2007-05-16; He Jutang, Chinese Patent: CN101037616, 2006-03-16).Shen Heping et al., Chinese Patent: CN1876767, 2006-06-28). Fixed-bed hydrotreating technology has a relatively simple process flow, generally including three units: pretreatment, hydrogenation, and separation. This process is relatively simple, with relatively low investment and operating costs. However, to ensure long-term operation, certain requirements are generally placed on the quality of the feedstock tar. The delayed coking-fixed-bed hydrotreating combined process technology converts the large molecules in coal tar into small-molecule light oil and larger-molecule coke through delayed coking; then, the light oil is used as feedstock for fixed-bed hydrotreating to produce naphtha and diesel oil. The advantage of the delayed coking-fixed-bed hydrotreating combined process is that it converts a portion of heavy coal tar into light oil products; the disadvantage is that the process flow is relatively complex, and a portion of the coal tar is converted into coke, failing to fully utilize coal tar resources. The characteristic of suspended-fixed-bed hydrocracking technology is that the catalyst is freely suspended in the liquid phase of the suspended-bed reactor and can be discharged with the material, avoiding the negative impact of pollutants in the feed tar on the catalyst activity due to deposition and coking, so that the activity of the catalyst in the reactor is stabilized at an appropriate level, thereby achieving long-term stable operation. The characteristic of fluidized-bed-fixed-bed hydrocracking technology is that the catalyst is uniformly dispersed in the liquid phase of the reactor (fluidized bed), and the catalyst can move freely but does not flow out of the fluidized-bed reactor with the generated oil. In order to maintain the relative stability of the catalyst activity in the reactor, the fluidized-bed reactor can unload the used catalyst and fill it with new catalyst or regenerated catalyst online at a certain rate. Polish scientists (Magdalena Majka et al, Journal of the Energy Institute, 2018, 91(6): 1164-1176). Magdalena Majka's team studied the hydrocracking process of coal tar on different catalysts. The results showed that Ni-W / Al2O3 and Y zeolite catalysts have high catalytic activity for the hydrocracking of light aromatics. Huang Peng et al. from the Coal Research Institute (Huang Peng et al., Journal of Fuel Chemistry, 2020, 48(9): 1079-1086). Researchers prepared a low-temperature coal tar hydrocracking catalyst and evaluated its hydrocracking performance in a fixed-bed cracking unit, including two-stage reactors for hydrorefining and hydrocracking. The results showed that the catalyst had a good hydrocracking effect, and after loading 14.9% of MoO3 active metal, the yield of hydrocracking products naphtha and jet fuel could reach 79.21%. Hu Jinyu et al. from Shaanxi Yanchang Petroleum Company (Hu Jinyu et al., Refining & Chemical Industry, 2020, 31(5): 25-27). They systematically analyzed the current status and application of suspended-bed coal tar hydrocracking technology. The study showed that when 2% catalyst was added during coal tar hydrocracking, under optimal reaction conditions, the conversion rate of heavy components was close to 100%, and the liquid yield could reach 90%.In summary, (1) the H / C ratio in low-temperature coal tar is closer to that of petroleum. Compared with medium- and high-temperature coal tar, low-temperature coal tar is more suitable for hydrogenation, thereby obtaining clean gasoline, diesel and other fuel oils. (2) The selection and preparation of hydrogenation catalysts are the key to coal tar hydrogenation refining. The level of catalyst activity is directly related to the effect of coal tar hydrogenation. The addition of a small amount of additives can significantly improve the pores of the carrier and the dispersion of active components. At the same time, the control of hydrogenation process conditions also has a certain impact on the hydrogenation reaction. (3) Compared with fixed-bed hydrogenation reactors, suspended-bed hydrogenation reactors have the advantages of high hydrogenation conversion rate and liquid yield. Suspended-bed hydrogenation technology is still a hot topic for future research. Coal tar hydrogenation technology can significantly improve the quality of tar and can be directionally converted into products such as gasoline, diesel, aviation kerosene, and special functional oils. However, coal tar hydrogenation technology has problems such as high energy consumption. Summary of the Invention

[0006] This invention addresses the problems of low coal pyrolysis tar quality and high energy consumption in the coal tar hydrogenation process by providing an integrated device and process for coupling coal pyrolysis and tar hydrogenation, which can improve coal tar quality while reducing process energy consumption.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] An integrated coal pyrolysis and tar hydrogenation coupling device includes a coal pyrolysis reactor, a tar hydrogenation reactor, and a tar collection device. The coal pyrolysis reactor includes a preheating and conveying system and a fluidized bed reactor. The preheating and conveying system includes a solid heat carrier, which is iron-loaded aluminum-magnesium spinel. The fluidized bed reactor is equipped with several staggered baffles. The coal pyrolysis reactor is connected to the feed inlet of the tar hydrogenation reactor, and a heating device is installed on the connecting pipeline. The temperature of the heating device is not lower than that of the tar hydrogenation reactor. The product outlet of the tar hydrogenation reactor is connected to the tar collection device.

[0009] Furthermore, the coal pyrolysis reactor also includes a hydrogen conveying system and a pulverized coal conveying system. The hydrogen conveying system is connected to the hydrogen inlet of the fluidized bed reactor, and the preheating conveying system and the pulverized coal conveying system are respectively connected to the preheating port of the fluidized bed reactor.

[0010] Furthermore, the temperature of the fluidized bed reactor is 400℃~700℃.

[0011] Furthermore, the baffle plate is connected to the inner wall of the fluidized bed reactor at an angle of 15° to 60°.

[0012] Furthermore, the tar hydrogenation reactor includes a hydrogen replenishment system and a fixed-bed reactor. The hydrogen replenishment system is connected to the hydrogen replenishment port of the fixed-bed reactor. The fixed-bed reactor is equipped with a hydrogenation catalyst, and the temperature of the fixed-bed reactor is 350℃~550℃.

[0013] Furthermore, the hydrogenation catalyst comprises a supported metal or sulfide catalyst composed of nickel, molybdenum, tungsten, cobalt, and rubidium.

[0014] Furthermore, the fluidized bed reactor and the fixed bed reactor are connected and a dust collector is installed in between, and the fluidized bed reactor and the dust collector are respectively connected to the semi-coke and heat carrier separation system.

[0015] Furthermore, the tar collection device includes an electrostatic precipitator and a gas-liquid separation and condensation device. The inlet of the electrostatic precipitator is connected to the product outlet of the fixed-bed reactor, and the tar droplets and gas outlet of the electrostatic precipitator are connected to the gas-liquid separation and condensation device.

[0016] Furthermore, the tar outlet of the electrostatic precipitator and the outlet of the gas-liquid separation and condensation device are respectively connected to an oil storage tank.

[0017] An integrated process for coupling coal pyrolysis and tar hydrogenation, using the aforementioned integrated coal pyrolysis and tar hydrogenation device, includes the following steps:

[0018] Step 1: Obtain the products of coal pyrolysis using a coal pyrolysis reactor;

[0019] Step 2: The products of coal pyrolysis are hydrogenated in a coal tar hydrogenation unit and then enter a tar collection unit.

[0020] Step 3: Use a tar collection device to capture tar and separate and condense the tar droplets and coal gas to obtain coal tar.

[0021] Compared with the prior art, the present invention has the following beneficial technical effects:

[0022] This invention provides an integrated coal pyrolysis and tar hydrogenation coupling device. By coupling the coal pyrolysis reactor and the tar hydrogenation reactor, and the process flow, energy consumption can be significantly reduced. The staggered distribution of baffles increases the mixing degree between the solid heat carrier and pulverized coal, improving the heat transfer efficiency of the fluidized bed reactor. The solid heat carrier used is iron-loaded aluminum-magnesium spinel, which not only provides heat to the pulverized coal but also provides a catalytic effect for coal pyrolysis.

[0023] Furthermore, the electrostatic precipitator has high tar collection efficiency, low resistance loss, and large gas throughput, thus improving product recovery rate.

[0024] The present invention provides an integrated process for coupling coal pyrolysis and tar hydrogenation, which can achieve targeted conversion of coal pyrolysis products, increase aromatic content, reduce oxygen content, and improve the quality of coal pyrolysis products through optimization of catalyst and process conditions. Attached Figure Description

[0025] The accompanying drawings are provided to further understand the invention and constitute a part of this invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0026] Figure 1 This is a schematic diagram of the integrated coal pyrolysis and tar hydrogenation coupling device and process described in this invention.

[0027] Among them, 1 is the hydrogen conveying system, 2 is the preheating conveying system, 3 is the pulverized coal conveying system, 4 is the fluidized bed reactor, 5 is the dust collector, 6 is the semi-coke and heat carrier separation system, 7 is the hydrogen replenishment system, 8 is the fixed bed reactor, 9 is the electrostatic precipitator, 10 is the oil storage tank, 11 is the gas-liquid separator, and 12 is the baffle plate. Detailed Implementation

[0028] The present invention will now be further described as follows:

[0029] See Figure 1 An integrated coal pyrolysis and tar hydrogenation coupling device is disclosed, comprising a coal pyrolysis reactor, a tar hydrogenation reactor, and a tar collection device. The coal pyrolysis reactor includes a preheating and conveying system 2 and a fluidized bed reactor 4. The preheating and conveying system 2 includes a solid heat carrier, which is iron-loaded aluminum-magnesium spinel. The fluidized bed reactor 4 is equipped with several staggered baffles 12. The coal pyrolysis reactor and the tar hydrogenation reactor are arranged in parallel, with the raw material inlets of the two reactors connected. A heating device is installed on the connecting pipeline. The product outlet of the tar hydrogenation reactor is connected to the tar collection device. The coupling of the two reactors and the process significantly reduces process energy consumption. The staggered baffles increase the mixing degree between the solid heat carrier and the pulverized coal, improving the heat transfer efficiency of the fluidized bed reactor. The iron-loaded aluminum-magnesium spinel used as the solid heat carrier not only provides heat to the pulverized coal but also provides a catalytic effect for coal pyrolysis.

[0030] The coal pyrolysis reactor includes a hydrogen conveying system 1 and a coal powder conveying system 3. The hydrogen conveying system 1 is connected to the hydrogen inlet of the fluidized bed reactor 4. The preheating conveying system 2 and the coal powder conveying system 3 are respectively connected to the preheating port of the fluidized bed reactor 4. The temperature of the fluidized bed reactor (4) is 400℃~700℃. The baffle 12 is connected to the inner wall of the fluidized bed reactor 4 and the included angle is 15°~60°.

[0031] The tar hydrogenation reactor includes a hydrogen supply system 7 and a fixed-bed reactor 8. The hydrogen supply system 7 is connected to the hydrogen supply port of the fixed-bed reactor 8. The fixed-bed reactor 8 contains a hydrogenation catalyst, which includes a supported metal or sulfide catalyst composed of nickel, molybdenum, tungsten, cobalt, and rubidium. The temperature of the fixed-bed reactor 8 is 350℃~550℃. A fluidized-bed reactor 4 is connected to the fixed-bed reactor 8, with a dust collector 5 installed between them. The fluidized-bed reactor 4 and the dust collector 5 are respectively connected to the semi-coke and heat carrier separation system 6.

[0032] The tar collection device includes an electrostatic precipitator 9 and a gas-liquid separation and condensation device 11. The electrostatic precipitator 9 has high tar collection efficiency, low resistance loss, and large gas throughput, which improves the product recovery rate. The inlet of the electrostatic precipitator 9 is connected to the product outlet of the fixed bed reactor 8. The tar droplets and gas outlet of the electrostatic precipitator 9 are connected to the gas-liquid separation and condensation device 11. The tar outlet of the electrostatic precipitator 9 and the outlet of the gas-liquid separation and condensation device 11 are respectively connected to the oil storage tank 10.

[0033] An integrated process for coupling coal pyrolysis and tar hydrogenation, using an integrated coal pyrolysis and tar hydrogenation device, includes the following steps:

[0034] Step 1: Obtain the products of coal pyrolysis using a coal pyrolysis reactor;

[0035] Step 2: The products of coal pyrolysis are hydrogenated in a coal tar hydrogenation unit and then enter a tar collection unit.

[0036] Step 3: Use a tar collection device to capture tar and separate and condense the tar droplets and coal gas to obtain coal tar.

[0037] The present invention provides an integrated process for coupling coal pyrolysis and tar hydrogenation, which can achieve targeted conversion of coal pyrolysis products, increase aromatic content, reduce oxygen content, and improve the quality of coal pyrolysis products through optimization of catalyst and process conditions.

[0038] The present invention will be described in detail below with reference to embodiments:

[0039] Comparative Example 1

[0040] The coal sample used was from Shenmu, Shaanxi Province. The coal pyrolysis unit operated at 650℃, using iron-loaded aluminum-magnesium spinel as the solid heat carrier. The pyrolysis products bypassed the coal tar hydrogenation unit and went directly into the tar collection unit. The coal tar composition was: aliphatic hydrocarbons 19.16%, aromatic hydrocarbons 40.36%, oxygenated compounds 29.77%, and other components 10.71%. The coal tar distillation range distribution was: light oil 3.04%, phenolic oil 9.16%, naphthalene oil 4.51%, wash oil 17.60%, anthracene oil 19.67%, and bitumen 46.03%.

[0041] Example 1

[0042] The coal sample used was from Shenmu, Shaanxi Province. The coal pyrolysis unit operated at 650℃, using iron-loaded aluminum-magnesium spinel as the solid heat carrier. The pyrolysis products were then fed into a coal tar hydrogenation unit at 350℃, using Ni-Mo / Al₂O₃ as the catalyst. The resulting coal tar composition was: aliphatic hydrocarbons 11.57%, aromatic hydrocarbons 61.55%, oxygenated compounds 18.27%, and other components 9.61%. The coal tar distillation range distribution was: light oil 9.69%, phenolic oil 11.22%, naphthalene oil 11.03%, wash oil 22.41%, anthracene oil 19.68%, and bitumen 25.96%. The coupling of the two units reduced process energy consumption, significantly decreased the content of aliphatic hydrocarbons and oxygenated compounds, and significantly increased aromatic hydrocarbons, demonstrating an improvement in the quality of the coal pyrolysis products.

[0043] Example 2

[0044] The coal sample used was from Shenmu, Shaanxi Province. The coal pyrolysis unit operated at 650℃, using iron-loaded aluminum-magnesium spinel as the solid heat carrier. The pyrolysis products were then fed into a coal tar hydrogenation unit at 450℃, using W-Mo-Ni / Al2O3 as the catalyst. The resulting coal tar composition was: aliphatic hydrocarbons 10.82%, aromatic hydrocarbons 62.80%, oxygenated compounds 18.10%, and other components 8.28%. The coal tar distillation range distribution was: light oil 12.38%, phenolic oil 10.49%, naphthalene oil 20.07%, wash oil 19.44%, anthracene oil 18.38%, and bitumen 19.23%. The coupling of the two units reduced process energy consumption, significantly decreased the content of aliphatic hydrocarbons and oxygenated compounds, and significantly increased aromatic hydrocarbons, demonstrating an improvement in the quality of the coal pyrolysis products.

[0045] Example 3

[0046] The coal sample used was from Shenmu, Shaanxi Province. The temperature of the coal pyrolysis unit was 650℃, and the solid heat carrier was iron-loaded aluminum-magnesium spinel. The products of coal pyrolysis were fed into a coal tar hydrogenation unit at 550℃, using Ni-W / Al2O3 as the catalyst. The resulting coal tar composition was: aliphatic hydrocarbons 10.29%, aromatic hydrocarbons 65.66%, oxygenated compounds 17.51%, and other components 6.54%. The coal tar distillation range distribution was: light oil 11.99%, phenolic oil 9.90%, naphthalene oil 20.27%, wash oil 24.14%, anthracene oil 17.99%, and bitumen 15.71%. The coupling of the two units reduced process energy consumption, significantly reduced the content of aliphatic hydrocarbons and oxygenated compounds, and significantly increased aromatic hydrocarbons, demonstrating an improvement in the quality of the coal pyrolysis products.

[0047] 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 its scope of protection. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that after reading the present invention, they can still make various changes, modifications or equivalent substitutions to the specific implementation of the invention, but these changes, modifications or equivalent substitutions are all within the scope of protection of the pending claims of the invention.

Claims

1. A coal pyrolysis and tar hydrogenation integrated device, characterized in that, The device comprises a coal pyrolysis reaction device, a coal tar hydrogenation reaction device and a coal tar collection device; the coal pyrolysis reaction device comprises a preheating conveying system (2) and a fluidized bed reactor (4), the preheating conveying system (2) comprises a solid heat carrier, the solid heat carrier is iron-loaded aluminum magnesium spinel, a plurality of staggered distribution baffles (12) are arranged in the fluidized bed reactor (4), the temperature of the fluidized bed reactor (4) is 400-700 DEG C, the baffles (12) are connected with the inner wall of the fluidized bed reactor (4) and the included angle is 15-60 DEG, the coal pyrolysis reaction device is connected with the raw material inlet of the coal tar hydrogenation reaction device, a heating device is arranged on the connecting pipeline, the temperature of the heating device is not lower than the temperature of the coal tar hydrogenation reaction device; the product outlet of the coal tar hydrogenation reaction device is connected with the coal tar collection device; The coal pyrolysis reaction device further comprises a hydrogen conveying system (1) and a coal powder conveying system (3), the hydrogen conveying system (1) is connected with the hydrogen inlet of the fluidized bed reactor (4), and the preheating conveying system (2) and the coal powder conveying system (3) are respectively connected with the preheating port of the fluidized bed reactor (4); The coal tar hydrogenation reaction device comprises a hydrogen supplement system (7) and a fixed bed reactor (8), the hydrogen supplement system (7) is connected with the hydrogen supplement port of the fixed bed reactor (8), a hydrogenation catalyst is arranged in the fixed bed reactor (8), the temperature of the fixed bed reactor (8) is 350-550 DEG C, and the hydrogenation catalyst comprises a supported metal or sulfide catalyst composed of nickel, molybdenum, tungsten, cobalt and rubidium; The fluidized bed reactor (4) and the fixed bed reactor (8) are connected and a dust collector (5) is arranged therebetween, and the fluidized bed reactor (4) and the dust collector (5) are respectively connected with a semi-coke and heat carrier separation system (6); The coal tar collection device comprises an electric tar precipitator (9) and a gas-liquid separation condensing device (11), the inlet of the electric tar precipitator (9) is connected with the product outlet of the fixed bed reactor (8), the tar mist droplets and coal gas outlet of the electric tar precipitator (9) are connected with the gas-liquid separation condensing device (11), and the tar outlet of the electric tar precipitator (9) and the outlet of the gas-liquid separation condensing device (11) are respectively connected with an oil storage tank (10).

2. A coal pyrolysis and tar hydrogenation coupled integrated process, characterized in that, The device comprises a coal pyrolysis reaction device, a coal tar hydrogenation reaction device and a coal tar collection device; the coal pyrolysis reaction device comprises a preheating conveying system (2) and a fluidized bed reactor (4), the preheating conveying system (2) comprises a solid heat carrier, the solid heat carrier is iron-loaded aluminum magnesium spinel, a plurality of staggered distribution baffles (12) are arranged in the fluidized bed reactor (4), the temperature of the fluidized bed reactor (4) is 400-700 DEG C, the baffles (12) are connected with the inner wall of the fluidized bed reactor (4) and the included angle is 15-60 DEG, the coal pyrolysis reaction device is connected with the raw material inlet of the coal tar hydrogenation reaction device, a heating device is arranged on the connecting pipeline, the temperature of the heating device is not lower than the temperature of the coal tar hydrogenation reaction device; the product outlet of the coal tar hydrogenation reaction device is connected with the coal tar collection device; The coal pyrolysis reaction device further comprises a hydrogen conveying system (1) and a coal powder conveying system (3), the hydrogen conveying system (1) is connected with the hydrogen inlet of the fluidized bed reactor (4), and the preheating conveying system (2) and the coal powder conveying system (3) are respectively connected with the preheating port of the fluidized bed reactor (4); The coal tar hydrogenation reaction device comprises a hydrogen supplement system (7) and a fixed bed reactor (8), the hydrogen supplement system (7) is connected with the hydrogen supplement port of the fixed bed reactor (8), a hydrogenation catalyst is arranged in the fixed bed reactor (8), the temperature of the fixed bed reactor (8) is 350-550 DEG C, and the hydrogenation catalyst comprises a supported metal or sulfide catalyst composed of nickel, molybdenum, tungsten, cobalt and rubidium; The fluidized bed reactor (4) and the fixed bed reactor (8) are connected and a dust collector (5) is arranged therebetween, and the fluidized bed reactor (4) and the dust collector (5) are respectively connected with a semi-coke and heat carrier separation system (6); The coal tar collection device comprises an electric tar precipitator (9) and a gas-liquid separation condensing device (11), the inlet of the electric tar precipitator (9) is connected with the product outlet of the fixed bed reactor (8), the tar mist droplets and coal gas outlet of the electric tar precipitator (9) are connected with the gas-liquid separation condensing device (11), and the tar outlet of the electric tar precipitator (9) and the outlet of the gas-liquid separation condensing device (11) are respectively connected with an oil storage tank (10). The device comprises a coal pyrolysis reaction device, a coal tar hydrogenation reaction device and a coal tar collection device; the coal pyrolysis reaction device comprises a preheating conveying system (2) and a fluidized bed reactor (4), the preheating conveying system (2) comprises a solid heat carrier, the solid heat carrier is iron-loaded aluminum magnesium spinel, a plurality of staggered distribution baffles (12) are arranged in the fluidized bed reactor (4), the temperature of the fluidized bed reactor (4) is 400-700 DEG C, the baffles (12) are connected with the inner wall of the fluidized bed reactor (4) and the included angle is 15-60 DEG, the coal pyrolysis reaction device is connected with the raw material inlet of the coal tar hydrogenation reaction device, a heating device is arranged on the connecting pipeline, the temperature of the heating device is not lower than the temperature of the coal tar hydrogenation reaction device; the product outlet of the coal tar hydrogenation reaction device is connected with the coal tar collection device; The coal pyrolysis reaction device further comprises a hydrogen conveying system (1) and a coal powder conveying system (3), the hydrogen conveying system (1) is connected with the hydrogen inlet of the fluidized bed reactor (4), and the preheating conveying system (2) and the coal powder conveying system (3) are respectively connected with the preheating port of the fluidized bed reactor (4); The coal tar hydrogenation reaction device comprises a hydrogen supplement system (7) and a fixed bed reactor (8), the hydrogen supplement system (7) is connected with the hydrogen supplement port of the fixed bed reactor (8), a hydrogenation catalyst is arranged in the fixed bed reactor (8), the temperature of the fixed bed reactor (8) is 350-550 DEG C, and the hydrogenation catalyst comprises a supported metal or sulfide catalyst composed of nickel, molybdenum, tungsten, cobalt and rubidium; The fluidized bed reactor (4) and the fixed bed reactor (8) are connected and a dust collector (5) is arranged therebetween, and the fluidized bed reactor (4) and the dust collector (5) are respectively connected with a semi-coke and heat carrier separation system (6); The coal tar collection device comprises an electric tar precipitator (9) and a gas-liquid separation condensing device (11), the inlet of the electric tar precipitator (9) is connected with the product outlet of the fixed bed reactor (8), the tar mist droplets and coal gas outlet of the electric tar precipitator (9) are connected with the gas-liquid separation condensing device (11), and the tar outlet of the electric tar precipitator (9) and the outlet of the gas-liquid separation condensing device (11) are respectively connected with an oil storage tank (10). The device comprises a coal pyrolysis reaction device, a coal tar hydrogenation reaction device and a coal tar collection device; the coal pyrolysis reaction device comprises a preheating conveying system (2) and a fluidized bed reactor (4), the preheating conveying system (2) comprises a solid heat carrier, the solid heat carrier is iron-loaded aluminum magnesium spinel, a plurality of staggered distribution baffles (12) are arranged in the fluidized bed reactor (4), the temperature of the fluidized bed reactor (4) is 400-700 DEG C, the baffles (12) are connected with the inner wall of the fluidized bed reactor (4) and the included angle is 15-60 DEG, the coal pyrolysis reaction device is connected with the raw material inlet of the coal tar hydrogenation reaction device, a heating device is arranged on the connecting pipeline, the temperature of the heating device is not lower than the temperature of the coal tar hydrogen

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