China Chemical Industry News: Coal chemical industry gains further momentum through cross-sector integration

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China Chemical Industry News: Coal chemical industry gains further momentum through cross-sector collaboration. Author/Source: Date: 2016-08-08. Clicks: 6. Four years of hard work finally paid off. From July 26th to 27th, four new technologies developed by the Carbon-Hydrogen Efficient Utilization Technology Research Center of Yanchang Petroleum Group – namely pressurized pyrolysis of fluidized bed coal, co-pyrolysis of biomass and coal, direct conversion of methane into aromatics with hydrogen production as a by-product, and high-efficiency catalysts for suspended-bed hydrocracking – were evaluated for their scientific and technical merits in Xi’an by the Shaanxi Petroleum and Chemical Industry Federation. Experts deemed that these technologies are at the international or domestic leading level. What are the key strengths of these technologies? What is the significance of cross-sectoral integrated development in the coal chemical industry? Can the technical barriers to the integrated development of coal chemical industry and other industries be overcome? A reporter from China Chemical Industry News conducted an interview. Rapid pyrolysis of coal dust: a low-cost green method for power generation. Li Dapeng, the group’s leading expert in coal chemical engineering and director of the Hydrocarbon Center, said that the fluidized-bed rapid pyrolysis process uses coal dust as raw material, and a fluidized-bed reactor is employed to carry out rapid pyrolysis under hydrogenated and pressurized conditions in order to produce coal tar. Due to the extremely short pyrolysis reaction time of this technology, secondary reactions of the primary pyrolysis products are significantly reduced, thereby maximizing the liquid yield. It is reported that one of the innovative aspects of this technology is the fluidized-bed riser-type pyrolysis reactor that uses gas-solid mixtures as the heat carrier. Through pressurized pyrolysis in a hydrogen atmosphere, it enables a high yield of tar while increasing the operational load of the system, which facilitates the separation and recovery of subsequent products and improves the overall energy efficiency of the facility. At the same time, an efficient technology and equipment for separating pyrolysis oil gas from coke powder was developed, reducing the dust content in coal tar and meeting the requirements for downstream processing. The test setup established by the Yanchang Petroleum Hydrocarbon Center (1.0 MPa, 10 kg/hour) was used to conduct 20 cold feeding tests, 26 cold mold tests, and 134 hot feeding tests across 4 phases, thereby generating a relatively comprehensive set of basic data and patterns related to pyrolysis. The results showed that the yield of coal tar exceeded the current industry average of 6–8%. Under the optimized process conditions, the yield of coal tar can reach up to 18.27%, with an average of 15.14%, which represents the highest level currently achievable. On this basis, the Yanchang Petroleum Hydrocarbon Center has built an industrial demonstration pilot plant for the Coal-to-Tar and Syngas Integration Technology (CCSI) with a capacity of 36 tons per day. This system uniquely combines coal pyrolysis with semi-coke gasification within a single reactor, enabling staged conversion and optimized integration; the products include coal tar, syngas, and their downstream derivatives, thus achieving oil production at both stages of the process. To date, 3 operation tests have been completed, with a coal tar recovery rate of over 15%. If 100 million tons of pulverized coal are processed per year, 15 million tons of high-quality coal tar will be produced, which is equivalent to creating another oil field with a production capacity of 10 million tons. If syngas is processed into fine chemical products, its added value increases further. “The significance of this technology extends far beyond these aspects; the crude syngas produced by CCSI (using air as a gasifying agent) can also be used for power generation. By integrating it with green power generation technologies and expanding its industrial applications, it is possible to create a new integrated model for the clean and efficient conversion of coal, the advanced processing of coal tar, and green power generation – a multi-product system combining coal, electricity, and chemicals. ”Li Dapeng told reporters that coal-fired units account for over 70% of the total in our country. Calculations show that if the coal boilers in existing power plants are upgraded with CCSI-based 300MW-class subcritical gas turbine power generation technology, the cost of such upgrades would be around 50 million yuan. The overall energy efficiency would reach 42.99%, while the coal consumption per unit of electricity generated would drop to 293.16 gec/kWh; as a result, the pollutants in the exhaust gases produced would be significantly reduced. If a new CCSI unit is equipped with a 350MW-class gas turbine generator set, the investment cost is approximately 6,000–7,000 yuan/kWh. The overall energy efficiency reaches 46.85%, while the equivalent coal consumption for power generation drops to 264.62 gec/kWh. The flue gases generated meet the ultra-low emission standards required by gas turbine systems. Due to the low cost of syngas produced by CCSI, with raw material costs equivalent to only about 0.74 yuan/Nm3 for natural gas, its competitiveness and economic efficiency are greatly improved. If 60% of coal-fired power plants are integrated with CCSI technology, 180 million tons more coal tar can be produced while generating green electricity, which exceeds half of China’s crude oil imports. The appraisal committee, headed by He Yongde, an expert from the Coal Chemical Industry Committee of the China Petroleum and Chemical Industry Federation and honorary president of the Shaanxi Chemical Industry Society, concluded that this new coal pyrolysis technology features innovative concepts and strong creativity, and is at the leading level in China; it holds great significance for improving the efficient and clean utilization of low-grade coal. It is recommended to accelerate the industrial trials of integrated coal powder pyrolysis and gasification in order to realize the transformation and dissemination of scientific and technological achievements as soon as possible. “The organic combination of pressurized rapid pyrolysis of coal dust and semi-coke gasification not only results in a high yield of coal tar, but also enables full utilization of the hydrogen resources present in that tar. This approach can be used either for Fischer-Tropsch oil production or for power generation; the investment required is significantly lower than that for IGCC, and the cost of power generation is greatly reduced – it’s truly a win-win situation. ”Li Junfa, the chief engineer of the Petroleum and Chemical Industry Planning Institute, also gave high praise to this technology. Biomass and co-pyrolysis: Maximizing synergistic effects. In recent years, research on the co-pyrolysis of biomass and coal has attracted considerable attention; however, due to the significant difference in their pyrolysis temperatures, there is still debate regarding the existence of synergistic effects. Building on pressurized pyrolysis of coal, the Hydrocarbon Center of Yanchang Petroleum has proposed a new two-step pyrolysis approach that involves processing biomass and coal separately. It has developed patented technologies such as a pressurized continuous feeding device and a heat-coupled fluidized-bed reactor for the simultaneous pyrolysis of biomass and coal. Li Dapeng said that this rapid co-pyrolysis of biomass and coal in a fluidized bed represents a new low-cost process for increasing tar yield. By using a self-designed spiral feeding device for biomass, problems such as entanglement and bridging caused by the poor flowability of biomass are resolved, thereby enabling continuous and stable material transfer. Since biomass and coal are pyrolyzed separately in stages within an integrated reactor, their pyrolysis occurs at the optimal reaction temperatures. Moreover, the pyrolysis of biomass produces H2 as well as metal elements such as K, Ca, and Na, which exert a hydrogenation and catalytic effect on the pyrolysis of coal. At the same time, coal pyrolysis generates sufficient amounts of free radicals. The secondary reactions of biomass oil, along with the reduction reactions of semi-coke, release H2 and CO, providing ample hydrogen donors for the coal. When an optimal balance is achieved between free radicals and hydrogen donors, the advantages of biomass oil and coal tar complement each other, thereby increasing the yield of pyrolyzed oil and maximizing the synergistic effects of co-pyrolysis. It is reported that the 10 kg/h fluidized bed rapid pyrolysis testing setup developed by the Yanchang Petroleum Hydrocarbon Center, after 77 repeated experiments, identified suitable biomass straws and coal types; the optimal mixing ratio of biomass to coal was determined to be 70%:30% (by weight), resulting in a total tar yield of 16–20% and a synergistic effect of 20–40%. Furthermore, from the perspective of oil quality analysis, the low content of phenolic compounds and O-, N-, and S-heterocyclic compounds in the co-pyrolyzed oil, along with a high content of aromatic compounds, indicates significant hydrogenation of the biomass, making it suitable as a raw material for the chemical industry as well as for the hydrogenation production of gasoline and diesel. According to statistics, China’s straw production in 2015 was approximately 800 million tons, equivalent to about 400 million tons of standard coal, of which 60% was used as energy. If this inexpensive renewable green resource is pyrolyzed together with coal to produce tar, it will yield substantial economic benefits as well as significant environmental advantages. He Yongde believes that there is a significant synergistic effect when biomass and coal are pyrolyzed together rapidly and efficiently, which improves the pyrolysis efficiency and tar yield, as well as the quality of the oil products. This technological achievement is at the leading level in China, and it is of great significance for improving the clean and efficient utilization of low-metamorphism coal and biomass. It is recommended to strengthen research on the directed conversion of coal and biomass through co-pyrolysis for the development of fine chemicals. Production of aromatics from methane with hydrogen as a by-product: Both resources are valuable. The technology for directly converting methane into aromatics while producing hydrogen makes use of resources rich in methane and lower hydrocarbons such as ethane, found in natural gas, shale gas, and coalbed methane. Under anaerobic conditions, this process enables the direct conversion of these resources into aromatics such as benzene, toluene, and naphthalene, which are in short supply in China. At the same time, valuable hydrogen is produced as a by-product, thereby maximizing the utilization of resources and the value of the products. This approach can also be integrated with petrochemical and coal chemical industries for coordinated development. “The greatest advantage of this technology is that it yields both aromatics and hydrogen as a by-product, allowing it to be developed in conjunction with coal chemical industries. ”The appraisal committee, headed by Men Cungui, an expert from CNPC’s Consulting Center and former chief engineer of CNPC’s Refining and Chemicals Bureau, concluded that although methane-to-aromatics technology has been studied both domestically and internationally, the new fluidized-bed regeneration cycle process developed by Yanchang Petroleum’s Hydrocarbon Center is unique; moreover, it features the largest experimental scale, placing this achievement at the international leading level as a whole. To address the issues in methane anaerobic aromatization such as low one-pass conversion rate, rapid catalyst deactivation, and difficulty in maintaining continuous reaction-regeneration cycles, an experimental setup for a fluidized reaction-regeneration cycle in methane anaerobic aromatization was developed (with an inner diameter of 50 millimeters for both the reactor and regenerator, and a maximum catalyst loading of 300 grams), enabling continuous and stable operation. The experimental results from the circulating fluidized bed device show that the methane conversion rate remains above 15%, the benzene selectivity is around 45%, and the aromatic selectivity is above 55%, thereby laying a foundation for pilot-scale scaling up. Highly efficient catalysts: Accelerating the localization process. The suspended-bed hydrocracking catalysts produced using an oxidation, precipitation, and loading one-step method in petroleum hydrocarbon processing are micro-nano structured composite catalysts. They are primarily used in direct coal liquefaction, kerosene co-processing, the conversion of heavy and low-quality oils into lighter ones, and the hydrogenation of coal tar. These catalysts improve conversion rates and liquid yields while reducing the risk of coking. They contribute to the wider adoption of suspended-bed hydrocracking technology as well as to the clean utilization of coal and the efficient use of heavy and low-quality oils. They will replace the imported catalysts currently in widespread use in the field of coal-to-oil conversion, thus accelerating the localization of advanced technologies. “The innovation of this iron-based catalyst lies in the highly effective combination of a nanoscale α-FeOOH active component with a micrometer-scale carbon material carrier that possesses a large specific surface area. Its production process is characterized by short duration, good controllability, and low cost. In terms of performance, it not only achieves high conversion rates and yields of liquids but also has the ability to reduce coking. ”Men Cungui told reporters that the achievement is generally at the international leading level, and he suggested accelerating the scale-up of catalyst production for industrial use as well as its widespread application. It is understood that the Hydrocarbon Center of Yanchang Petroleum has completed the preparation of catalysts on a kilogram scale, and has carried out continuous performance evaluation experiments using these catalysts in a pilot-scale hydrocracking unit with a capacity of 150 kilograms per day. Compared with the commercial catalysts currently used in Yanchang Petroleum’s industrial demonstration plant for kerosene co-processing, the amount of catalyst required is reduced by 45%, while the liquid yield…