"What technical challenges must coal chemical industry overcome during the 13th Five-Year Plan period?

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"What technical challenges must coal chemical industry overcome during the 13th Five-Year Plan period? Author/Source: Huahua Net Coal Chemicals Date: 2016-03-18 Clicks: 5 I. Review of the Development of Modern Coal Chemicals during the 12th Five-Year Plan Period During the 12th Five-Year Plan period, it was widely recognized that the rapid development of modern coal chemicals was one of the most notable achievements in the development of the petrochemical industry. With the completion and commissioning of a number of coal chemical demonstration projects, modern coal chemical production facilities equipped with technologies owned through independent intellectual property rights have moved from the laboratory stage to commercial operation. This is a milestone in development: on the one hand, significant breakthroughs have been achieved in the core engineering technologies, and on the other hand, there has been substantial growth in terms of product scale. From any perspective, China’s modern coal chemical industry is now at the forefront of the world. 1.1 Major breakthroughs in core technologies: Gasification technology is a key technology in coal chemical industry; generally, problems in the production of coal chemical projects are related to the stable operation of gasification processes. Gasification: Multi-nozzle opposed gasifiers; 109 such gasifiers have been built, of which 40 are already in operation ； 72 space furnaces have been built, of which 24 are in operation ； The Water Wall Tsinghua Furnace, the two-stage furnace developed by Xi’an Thermal Power Institute, the Wuhuan Furnace, the Dongfang Furnace, and others have all made significant breakthroughs in key technologies for advanced coal gasification. According to relevant information, modern coal gasification processes can be used to gasify approximately 200 million tons of coal. Coal-to-oil: Shenhua’s coal direct liquefaction technology has been successfully applied in the Baotou 1 million t/a coal-to-oil demonstration project ； The coal indirect liquefaction process developed jointly by the Shanxi Institute of Coal Chemistry of the Chinese Academy of Sciences and China Synthetic Oil Corporation, which utilizes high-temperature slurry-bed F-T synthesis, has seen the construction of demonstration plants with a capacity of 160,000 tons per year for coal indirect liquefaction at Yitai, Lu’an, and Shenhua Baotou – these plants have now been successfully put into operation. Coal-to-methanol, olefins, and aromatics: The DMTO process for converting methanol into olefins developed by the Dalian Institute of Chemical Physics has seen the construction of a 600,000-t/year MTO pilot plant in Shenhua’s Ordos facility, which has yielded excellent results ； The 600,000 t/a MTP methanol-to-propylene plant built by Shenhua Ningmei has been put into operation, achieving significant economic benefits as well ； Tsinghua University has seen success with the pilot-scale plants for methanol-to-aromatics (FMTA) and methanol-to-propylene (FMTP) developed in collaboration with Huadian and Sinochem respectively. The kerosene co-refining hydrogenation process developed by Yanchang Petroleum Group has also seen the construction of a demonstration plant with an annual capacity of 450,000 tons, achieving an energy efficiency of over 70%. Ethylene glycol produced from coal: Ethylene glycol manufactured from coal has been developed by the Fuzhou Institute of the Chinese Academy of Sciences, Pu Jing, Donghua University, Wuhuan Group, and Sinopec; more than a dozen ethylene glycol production facilities have been built, with a total capacity of 1.65 million tons per year. Coal-to-natural gas: The first phase of production capacity of 1.3 billion m3/year for natural gas, developed by Datang Keqi and Xinjiang Qinghua Construction, has been put into operation. In summary, modern coal chemical industry has contributed to the diversification of China’s petrochemical products. 1.2 Ultra-large-scale development and industrial clustering in coal chemical industry: Modern coal chemical products witnessed rapid growth during the 12th Five-Year Plan period, both in terms of structure and scale. Coal-to-olefins: Ten olefins plants have been built and put into operation, each with a capacity of approximately 600,000 tons per year. The total olefins production capacity is nearly 5 million tons per year ； Coal-to-oil: 5 coal-to-oil units have been built and put into operation, with a total oil production capacity of 2.4 million tons per year; each individual unit has a capacity of 1 million tons per year ； Coal-to-natural gas: 5 coal-to-natural gas plants have been built, with each plant having a capacity of 1.3 billion m3/year, 2 billion m3/year, or 4 billion m3/year; the total production capacity amounts to 17 billion m3/year ； Coal-to-methanol: Methanol production facilities that have been built have an annual capacity of around 40 million tons; the capacity of individual plants ranges from 600,000 tons per year to 1 million tons per year and 1.5 million tons per year ； Ethylene glycol produced from coal: Over a dozen demonstration projects for ethylene glycol production have been built, with each unit having an annual production capacity of 200,000 tons; the total annual production capacity for ethylene glycol thus amounts to 1.65 million tons. 1.3 Significant progress has been made in the development of coal chemical industry parks. Important advances have taken place in these parks, which are mainly located in coal-producing regions such as Inner Mongolia, Shaanxi, Ningxia, Shanxi, and Xinjiang. Within coal chemical industry parks, incentives such as **policy and local** support, along with the parks’ flexible mechanisms and development plans, have helped to foster a number of dynamic large-scale coal chemical and energy construction bases. The layouts of locations such as the Ordos Coal Chemical Industry Base in Inner Mongolia, the Ningdong Large-Scale Energy, Coal-Electricity and Olefins Base in Ningxia, and the Junggar East Coal Chemical Industry Park in Xinjiang are highly conducive to the integrated development of the upstream and downstream industrial chains for modern coal chemical enterprises. II. Key research topics in coal chemical industry during the 13th Five-Year Plan period. There are many topics that need to be studied in the field of coal chemistry; only some of them are listed here to address the most urgent needs. 2.1 Challenges in the planning and layout of coal chemical industries **There are strict requirements for the location of modern coal chemical projects; priority should be given to areas with coal resources as well as key development zones ； Priority should be given to areas with relatively abundant water resources and good environmental capacity, as well as those that are in line with environmental protection plans ； For coal chemical projects to be located in areas lacking environmental capacity, measures such as economic structural adjustment and the substitution of coal consumption with an equivalent or reduced amount of other energy sources must be taken in advance to create such capacity. Advanced processing technologies and pollution control techniques should also be employed to minimize pollutant emissions to the greatest extent possible. 2.2 Bottlenecks in water resource utilization: China is a country facing water shortages. There is a mismatch between coal resources and water resources – areas with coal lack water, while areas with water lack coal. The main coal-producing areas and the bases for coal chemical projects are mostly located in regions with relatively scarce water resources and relatively fragile environments. Coal chemical industry is a sector that consumes large amounts of water. The main sources of water consumption include process steam used in chemical reactions, system water required to replace water lost through evaporation or leaks in cooling systems, water for desalination processes, and fresh water for domestic use. Additionally, this industry generates a large amount of wastewater, posing a significant threat to the environment. Without implementing effective water-saving measures such as water-saving technologies for open-loop cooling water systems, air cooling technology, closed-loop condensate recovery technology, as well as technologies for the hierarchical and reuse of water, it will be impossible to reduce water consumption per unit and wastewater discharge, which in turn affects the location planning of coal chemical projects. 2.3 Issues related to the discharge of high-concentration organic wastewater: High-concentration organic wastewater mainly originates from wastewater generated in coal gasification processes. Its characteristic is that the main pollutant is COD, with levels generally exceeding 2,000 mg/L. Typical examples of high-concentration organic wastewater include petroleum/chemical industrial wastewater. For instance, the mass concentration of COD in the effluent from main production sections generally exceeds 3,000–5,000 mg/L; in some sections, it even surpasses 10,000 mg/L ； Even the mixed water from various processing stages generally has a concentration of over 2,000 mg/L; in some cases, it can reach tens of thousands of mg/L. The BOD of petroleum/chemical wastewater is also high. The ratio of its BOD to COD is greater than 0.3. This type of wastewater is relatively easy to treat, but due to the large volume of water, improper selection of wastewater treatment processes, insufficient investment, or high pollution levels, it becomes difficult to meet the required standards for the treated water. As a result, most companies simply send this wastewater to evaporation ponds for treatment, which has an adverse impact on the surrounding environment. 2.4 Problems in treating wastewater containing high concentrations of recalcitrant organic substances. There are many types of recalcitrant organic substances; their main characteristics include high concentrations of organic matter, high levels of recalcitrance, and high contents of toxic substances, oils, ammonia, and nitrogen. The ratio of BOD to COD is well below 0.3. Coking wastewater contains not only high concentrations of ammonia nitrogen, but also polycyclic compounds such as phenol and its homologs like naphthalene, anthracene, and benzo[a]pyrene. In addition, it contains **, sulfides, and sulfur** as well. Such wastewater is rich in organic compounds, primarily aromatic and heterocyclic compounds; it also contains sulfides, nitrides, heavy metals, and toxic organic substances. It has a high color intensity, an unpleasant odor, and emits a pungent stench, as well as being highly acidic or alkaline ； Wastewater generated by processes such as low-temperature gasification and pyrolysis of low-rank coal has a very complex composition, and it is difficult to treat using conventional biochemical methods. Even with pretreatment facilities for removing phenols and ammonia from the tar, as well as for recovery, the COD of the organic wastewater remains high, indicating poor biodegradability. The reason for the difficulty in biological treatment is essentially determined by the characteristics of its hard-to-degrade species. In addition to the external environmental conditions during treatment (such as temperature, pH, etc.) not being at the optimal levels for biological treatment, another important reason is that the chemical composition and structure of the compounds themselves are very complex; there are no enzymes in the microbial community capable of breaking down these compounds, which gives them resistance to degradation ； At the same time, wastewater contains substances (organic or inorganic) that are toxic to microorganisms or can inhibit their growth, preventing the rapid degradation of organic matter. 2.5 Challenges in the Treatment and Recovery of High-Concentration Brine High-concentration saline wastewater is characterized by a high salt content. The salts in saline wastewater mainly originate from gas washing wastewater during the production process, discharge from cooling water systems, discharge from demineralized water systems, concentrated brine from reuse systems, and supplementary fresh water. In a coal-to-natural gas project, the amount of salt introduced into the system due to the use of Yellow River water as fresh water can account for around 60% of the total salt content in the system; followed by the salt generated by chemical agents added during the production process and in the water systems, at 29% and 13.6% respectively. The total dissolved solids (TDS) content in salt-containing wastewater from coal chemical industries is typically 500–5,000 mg/L, or even higher. After achieving “zero emissions” in coal chemical processing, the end product is impure salts containing various inorganic salts and a large amount of organic matter. Such mixed salts resulting from coal chemical evaporation crystallization are classified as hazardous waste and are subject to strict control. This type of mixed salt has extremely high solubility; its stability and solidification properties are poor, and it can seep out due to rain, causing secondary pollution. Currently, there are few existing hazardous waste treatment facilities capable of handling such mixed salts, and the treatment costs are very high. 2.6 The issue of homogenization among coal chemical products: The coal chemical industry has a relatively short history and limited R&D experience. Coupled with scarce resources and an inability to fully master core technologies and equipment, there is a significant tendency toward similarity among intermediate products in this industry; as a result, the industrial chain fails to develop extensively. Some end products are low-end items; intermediate raw materials such as polyethylene and polypropylene lack competitiveness. Without pursuing a differentiated development path, this will lead to another round of overcapacity. 2.7 Techno-economic challenges posed by low oil and gas prices: With high oil and gas prices, the competitiveness of coal-based chemicals is beyond doubt. However, in an era of low oil prices, such as when prices are below 60 dollars per barrel or 50 dollars per barrel, the cost competitive advantage of coal-based chemical industries faces significant challenges; it is therefore very important to determine appropriate countermeasures and for the government to introduce supportive policies. 2.8 Key technological innovation topics in coal chemical industry: The first is the pollution control technology for modern coal chemical industry (environmental protection technologies for treating and discharging three types of waste as well as recycling waste materials, along with energy-saving and water-saving technologies) ； Second is the core process technologies for the upgrading of modern coal chemical industry (modern coal gasification, syngas purification, synthesis, and technologies for the diversified and graded utilization of coal quality) ； Third is the technology related to the downstream product chains of modern coal chemical industry (high-end new material technologies such as synthetic materials, synthetic resins, and synthetic rubbers, specialization in fine chemicals, and high-value-added technologies) ； Fourth, there is still considerable room for technological innovation in the modern coal chemical industry’s coupling and integration technologies (product coupling technology, catalyst improvement technology, information control technology, and technologies related to domestically produced large-scale equipment), which the industry can explore and develop. III. Rules that must be followed in coal chemical industry during the 13th Five-Year Plan period 3.1 Basic principles to be adhered to in modern coal chemical industry During the 13th Five-Year Plan period, the task of the modern coal chemical industry is to carry out industrialization project demonstrations focusing on energy efficiency, environmental protection, water conservation, and the development of independent technical capabilities. By relying on these demonstration projects, efforts will be made to continuously improve the independent innovation technologies in this field, accelerate the shift toward cleaner methods of coal utilization, and provide strong support for the green and comprehensive use of coal. Adhere to proceeding based on water availability, and strictly control project development in water-scarce areas ； Ensure that energy efficiency, resource consumption, and pollutant emissions are converted in a clean and efficient manner, in compliance with legal requirements ； Adhere to leading by example, focus on advancing the construction of demonstration projects, and keep pace with the development of the industry ； Adhere to a scientific and rational layout; prohibit the construction of coal chemical projects in ecologically fragile and environmentally sensitive areas ； Adhere to the autonomy of technical equipment, and promote the use of technologies and equipment with independent intellectual property rights. 3.2 Modern coal chemical industries must adhere to strict guidelines regarding industrial layout. The establishment of such industries should take place within industrial parks, in compliance with the park’s planning requirements as well as environmental assessment standards. Do not establish factories in areas where the limits for total pollutant emissions, total water resource usage, or energy consumption have already been reached or exceeded ； Key ecological function areas designated in the “National Plan for Main Functional Zones” as areas where development is restricted or prohibited, as well as other areas requiring special protection ； Within 2 km outside the boundaries of the urban planning area, within 1 km on both sides of major rivers, highways, and railways, and within the health protection zones of residential areas. An incorrect site selection can lead to the serious consequence of a rejection of the environmental impact report for modern coal chemical industries. Coal chemical projects with serious environmental impacts cannot be approved. 3.3 Modern coal chemical industries must adhere to stricter water-saving standards. They should enhance water-saving measures to reduce the consumption of fresh water. In areas where conditions permit, mine dewatering water and reclaimed water should be used preferentially ； Coastal areas should use seawater as circulating cooling water ； In water-scarce areas, water-saving measures such as air cooling and closed-loop systems should be given priority ； The use of surface water must not displace ecological, domestic, or agricultural water needs ； The use of groundwater as production water is prohibited. Water efficiency should be improved as much as possible by adopting water-saving technologies and equipment such as air cooling, closed-loop systems, and wastewater pulping. The reuse rate of industrial water must be no less than 97%, and the recycling rate of cooling water must be no less than 98%. For new projects, in addition to referring to the actual data from existing demonstration projects that are already in operation, water-saving optimizations should be implemented during the design phase, following the principles of \"using more water where it is available in large quantities, using less water where it is scarce, separating clean water from wastewater, and making efficient use of water at various stages.\" 3.4 Modern coal chemical industries must adhere to stricter standards for exhaust gas emissions. When considering the emission of exhaust gases from coal chemical processes, it is necessary to take into account the local environmental capacity. In line with the requirements set out in the \"Action Plan for Clean and Efficient Utilization of Coal (2015–2020)\), which stipulate that emissions of air pollutants and wastewater must meet the strictest environmental protection standards, the \"Emission Standards for Pollutants in the Petrochemical Industry\" (GB 31571–2015) should be followed. Strictly control the increase in pollutant emissions, and make the total amount of pollutant emissions a prerequisite for environmental impact assessment approvals, with projects being approved based on this total amount. For new projects that emit sulfur dioxide, nitrogen oxides, industrial dust, and volatile organic compounds, measures to reduce pollutant emissions must be implemented in order to achieve increased production while simultaneously reducing emissions. For key control areas and cities with excessive atmospheric environmental quality, new projects must use a reduction level equivalent to twice that of existing sources in the region; for general control areas, a reduction level equivalent to 1.5 times that of existing sources is required. 3.5 Modern coal chemical industry should adhere to the standards for the effective control of volatile organic compounds. It is necessary to strictly follow the “Comprehensive Control Plan for Volatile Organic Compounds in the Petrochemical Industry” issued by the Ministry of Environmental Protection in 2014. For VOCs and similar substances, control measures should be implemented in accordance with the relevant requirements set forth in GB 31570 “Emission Standards for Pollutants from the Petroleum Refining Industry” or GB 31571 “Emission Standards for Pollutants from the Petrochemical Industry”, depending on the types of products produced by each project. Great importance should be attached to controlling the emissions of volatile organic compounds (VOCs) from coal chemical projects. Based on this, comprehensively verify the emissions status of volatile organic compounds. Measures should be taken for the dynamic and static sealing points of equipment, the storage and handling of organic liquids, the systems for collecting, temporarily storing, and treating wastewater, as well as coal preparation and storage, in order to effectively control the release and emission of volatile organic compounds (VOCs), malodorous substances, and other toxic and harmful pollutants. Improve control measures for uncontrolled emissions of volatile organic compounds from equipment such as gas/water separation units, phenol-ammonia recovery systems, water storage tanks, and gasification, purification, and sulfur recovery units. During the wastewater treatment process, targeted measures should be taken based on the concentration of volatile organic compounds. In the processes of collecting, storing, and treating wastewater, waste liquids, and waste residues, effective sealing and collection measures should be implemented at the key points where volatile organic compounds may escape, to ensure that the exhaust gases meet the relevant standard requirements after being collected and treated. Abnormally emitted exhaust gases should be sent to specialized equipment or facilities such as flares for treatment; direct discharge is strictly prohibited. 3.6 Modern coal chemical industries must adhere to strict CO2 emission reduction standards. Such industries should minimize CO2 emissions by optimizing processes and improving energy efficiency. They should make use of the advantages associated with the high concentration of CO2 produced in these industries, which facilitates its capture, and actively explore various treatment methods such as gas-driven oil extraction, geological storage, and the use of microalgae for oil production. Other applications include the production of urea, ammonium carbonate, dimethyl carbonate, methanol, PC, biodegradable plastics, as well as the conversion of CO2 into carbon monoxide using oxygen-rich conditions, and its use in natural gas methanation (through the recovery of CO2 from flue gases), as well as for edible purposes. 3.7 Modern coal chemical industries must adhere to stricter wastewater discharge standards. The treatment and discharge of wastewater in such industries should be planned in accordance with the principles of separating clean water from polluted water, treating polluted water separately, carrying out advanced treatment, and reusing water based on its quality; meanwhile, technologies that have been successfully applied industrially or in pilot projects and are economically viable should be utilized. In areas with suitable water bodies for receiving wastewater, the construction of modern coal chemical projects should ensure that wastewater discharges (including saline wastewater) meet the requirements of relevant pollutant emission standards, and that surface water bodies continue to fulfill their functions for downstream water use. Modern coal chemical projects built in areas lacking water bodies for wastewater discharge must not pollute groundwater, the atmosphere, soil, etc. The miscellaneous salts that crystallize out from the high-concentration wastewater in coal chemical industries are classified as hazardous solid waste due to their presence of organic substances and trace heavy metals. All of these mixed salts should be utilized or safely disposed of. At present, the technologies for the selective utilization of these mixed salts are still in the research phase, and there are also constraints such as the inadequacy of standards for downstream products. Therefore, great attention should be paid to effective disposal methods and technologies for wastewater with high salt content. 3.8 Modern coal chemical industry should strengthen efforts in the upgrading and innovation of core process technologies. It is necessary to further boost innovation in core process technologies, engineering technologies, and environmental control technologies, in order to achieve breakthroughs in key and core technologies. The process technology, engineering technology, and environmental protection and energy-saving emission-reduction control technologies of the project shall meet the requirements of **industrial policies, and upgraded processes with high energy conversion efficiency and low pollutant emission levels shall be adopted. During the industry demonstration phase, it is necessary to undertake environmental protection demonstration tasks in areas such as the efficient utilization of coal based on its different quality levels, the combined use of resources and energy, and the development of pollution control technologies (such as wastewater treatment technologies, wastewater disposal methods, and strategies for the use and disposal of crystalline salts). Additionally, measures should be proposed to address cases where the demonstrated technologies fail to achieve the expected results. At the same time, it is strictly prohibited to use coal varieties with high contents of aluminum, arsenic, fluorine, oil, and other rare elements—for which processing technologies, pollution prevention and control technologies, or comprehensive utilization technologies are not yet mature—as raw material coal or fuel coal. IV. Breakthroughs in the Upgrading of Demonstration Technologies for Coal Chemical Industry during the 13th Five-Year Plan Period: Pollution Control Technologies for Modern Coal Chemical Industry ； Core process technologies of modern coal chemical industry ； Technologies for the subsequent product chain in modern coal chemical industry ； Modern coal chemical industry coupling and integration technologies are key to the development and survival of the modern coal chemical industry during the 13th Five-Year Plan period. Focus on addressing environmental protection issues, survival issues, technical and economic problems, as well as core competitiveness issues. “During the 13th Five-Year Plan period, it is necessary to advance the industrialization of modern coal chemical industry and demonstration projects for technological upgrades in an orderly manner, standardize evaluation processes, and ensure clarity on three aspects. First, it is necessary to grasp the key indicators of benchmark demonstration projects, such as material consumption, energy consumption, water consumption, and emissions of various waste types; this includes the energy conversion efficiency of the demonstration projects, as well as the emission levels of sulfur dioxide (SO2), nitrogen oxides (NOx), and carbon dioxide (CO2) ； Second, it is necessary to understand the operating conditions of various units and rotating equipment, such as the production load of the demonstration project, as well as the product varieties and quality standards, safety and environmental protection measures, investment level, and economic benefits, in order to determine whether these indicators meet the design values ； Third, it is to gain experience from the operation of demonstration projects, summarize, identify, and analyze existing problems, thereby providing reliable data for further optimizing operations and carrying out technical upgrades. 4.1 EBA process for treating wastewater containing high concentrations of refractory organic compounds: Current coal gasification processes employ low-temperature gasification of low-rank coal, such as the Ruhr furnace; during this gasification process, the light components in the coal are converted into substances such as tar, phenols, ammonia, alkanes, aromatics, heterocycles, ammonia nitrogen, cyanides, pyridines, and alkylpyridines, which are generated alongside the coal gas. During the subsequent gas washing, cooling, and purification processes, the vast majority of these substances end up in the gas water; it constitutes a typical type of wastewater containing high concentrations of refractory organic compounds. Such wastewater is large in volume, toxic, harmful, and its complex composition makes it difficult to treat. The EBA process is used for the exploratory treatment of high-concentration phenol-ammonia wastewater generated by Ruchi reactors, BGL reactors, and low-temperature pyrolysis. Although such wastewater is treated using phenol-ammonia recovery processes, the wastewater that enters the biochemical treatment system remains complex and toxic; the mass concentration of phenolic compounds can reach 200–1,000 mg/L, while the mass concentration of ammonia nitrogen can reach 100–300 mg/L. This process utilizes technologies to improve the biodegradability of wastewater, reduce its toxicity, and enhance the activity of sludge, thereby enabling the treated effluent from high-concentration phenol-ammonia wastewater to meet the standards for reuse. As a processing approach, this technology requires further validation and improvement. 4.2 Water-saving technology for closed-air-cooled circulation cooling water: In closed-air-cooled circulation cooling water systems, soft water or deionized water is used as the cooling water to absorb heat from the process heat exchange equipment. After its temperature rises, this water enters energy-efficient water-film air coolers or combined air coolers where it is pre-cooled. Subsequently, it enters the spray section, where it loses heat to the air outside the tubes and to the spray water. Once its temperature has dropped, it is pressurized by a circulation pump and sent back to the process heat exchange equipment. Soft water is circulated in a closed-loop system, where it does not come into contact with the outside air to carry out the heat transfer process of absorbing and releasing heat. This process replaces traditional industrial circulating cooling water systems, using energy-efficient water film air coolers or combined air coolers in place of cooling towers. It ensures that the temperature of the cooling water meets the requirements of various processes, while also saving water, reducing scaling in piping and equipment, and extending the service life of these devices. It represents a approach to water conservation that still requires further verification and improvement. 4.3 Comprehensive utilization technology for salt separation through crystallization of high-concentration brine The technology of using multi-stage evaporation crystallization to convert high-concentration brine into mixed salts has been partially validated in the fertilizer project of China Coal Tuoke (BGL furnace), but there are still issues regarding the comprehensive utilization of such mixed salts. Given the difficulty in comprehensively utilizing crystalline salts in coal chemical industries, research on evaporation crystallization for salt separation represents one approach aimed at rendering these crystalline salts harmless and enabling their resource utilization to achieve \"zero emissions\"; pilot tests are necessary for this purpose. Only after the technical and economic feasibility as well as operational reliability of various pollution control measures have been thoroughly demonstrated can it be determined whether to grant access. Crystallization-based salt separation and comprehensive utilization technologies are used to separate sodium chloride and sodium sulfate through stepwise crystallization, as well as to determine how to deal with impurities such as the large amounts of organic matter present in concentrated brine. However, there is no experimental data on the effectiveness of this stepwise crystallization process. Moreover, the current quality standards for sodium chloride and sodium sulfate in China are not suitable for the production of salt from industrial wastewater. Since this technology provides a pathway for the comprehensive utilization of high-concentration brine, further verification is needed. 4.4 Comprehensive Utilization Technologies for Low-Rank Coal (Lignite) Based on Quality Classification and Grading: Integrated technologies that encompass the pre-treatment, gasification, synthesis, power generation, and heat supply of low-rank coal (lignite) represent a promising modern coal chemical technology for the comprehensive utilization of this type of coal through quality classification, grading, and improvement. Research and development of low-temperature (medium-temperature, high-temperature), fast (medium-speed) thermal carrier fluidized bed (fixed bed, fluidized bed) pyrolysis processes for low-rank coal, with the aim of producing tar, carbonized gas, and semi-coke as main products, constitutes an emerging trend in this field. This technology can give rise to various technical combinations; by combining pyrolysis with semi-coke gasification, and using the high-temperature gas generated from the gasification of semi-coke powder as a heat carrier for reverse cascade direct-contact pyrolysis, it is possible to make efficient and rational use of the sensible heat contained in that high-temperature gas, as well as to carry out staged pyrolysis of low-grade coal. Especially for low-rank coals with a high oil content, pyrolysis at medium to low temperatures (550–850 °C) is used to extract light components such as tar and gas, thereby yielding clean materials with a high calorific value ； Gas is used to produce hydrogen or methane ； Coal tar, after treatments such as phenol extraction, undergoes catalytic cracking with hydrogen to produce naphtha and diesel fractions ； Semicoke, from which the volatile components have been removed, has a higher calorific value and is cleaner than raw coal. It can be used for gasification to produce syngas, which in turn can be used to manufacture chemical products; it can also serve as high-quality fuel for domestic use and for power plants, thereby enabling the efficient and clean utilization of coal on a differentiated basis. 4.5 Refining and Production Technologies of Coal Tar The three major challenges in refining coal tar, which is obtained through the pyrolysis of low-rank coal and coking, namely dust removal from high-temperature gas, treatment of pyrolysis wastewater, and tar refining technologies, all have a significant impact on its comprehensive utilization. Oil/dust separation in high-temperature gas, the treatment and resource utilization of pyrolysis wastewater with high concentrations of tar, phenols, benzene, ammonia nitrogen, and COD, as well as the scaling up of the equipment – these are all three major challenges that hinder the pyrolysis of pulverized coal or coal in its entirety. They also represent the three obstacles that must be overcome for the selective and graded utilization of lower-grade coal. For example, the process of producing anthracite through low-grade coal powder rotary pyrolysis removes coal dust with a particle size of less than 0.2 mm while using hot flue gas to dry the coal powder, thereby significantly reducing the amount of such coal dust in the coal tar produced during the subsequent pyrolysis process. High-speed centrifugal separation technology is employed to effectively separate the tar containing a small amount of coal dust, thus addressing the problem of difficulty in separating oil and dust during coal powder pyrolysis. The lightweighting technology for medium- and low-temperature coal tar integrates and combines delayed coking technologies for coal tar; the hydrogenation of tar to produce naphtha and diesel fractions overcomes the challenges associated with the large-scale application of bituminous coal pyrolysis, hydrogen production from raw gas, and fixed-bed hydrogenation units for medium- and low-temperature coal tar ； The technology for hydrogenating the entire fraction of medium/low-temperature coal tar to produce large amounts of intermediate distillates (FTH) has become the world’s first industrial demonstration plant for the full-fraction hydrogenation of coal tar using a fixed-bed process ； CGPS technology feeds fines with a particle size of less than 25 mm into the belt furnace through staged distribution, thereby creating multi-layer moving particle beds. By utilizing a moving filter layer composed of different layers of particle coal, and based on filtration principles such as inertial collision, diffusion deposition, gravitational deposition, direct interception, and electrostatic attraction, this technology enables efficient self-dust removal from pyrolysis gas (with a dust removal efficiency of over 96%, and the dust content in the tar reduced to below 0.32 g/m3). 4.6 Large-scale clean coal low-energy gasification technology: Modern gasification is the core technology in coal chemical plants, and the choice of feed coal directly affects the energy efficiency, environmental protection, safety, investment, and profitability of modern coal chemical projects. The trends and directions in the development of modern coal gasification should take into account the characteristics of China’s coal, namely its diversity and complex composition. One should always strive for a upgraded gasification process that features high coal conversion efficiency, high gasification efficiency, high effective yield, low energy consumption, low costs, and excellent environmental sustainability. The pressurized gasification technologies for dry coal powder/water-coal slurry/chopped coal fluidized bed/moving bed should be further upgraded, integrated, and coupled, with larger-scale equipment developed; for example, multi-nozzle opposed-type pressurized fluidized bed technologies with a capacity of 3,000 t/d or more should be created to ensure stable production, long-term operation, and reduced investment costs ； Develop a pressurized rapid cooling fluidized bed technology with a capacity of 3,000 t/d or more to improve coal conversion rate, gasification efficiency, and effective yield, ensure stable production, and reduce costs ； Develop coal crushing pressurized fixed-bed technology with a capacity of 1,600 t/d or higher, improve the carbon conversion rate and utilization efficiency in coal crushing pressurized gasification, scale up the equipment, reduce steam consumption, and decrease wastewater generation and treatment volume ； Develop wet coal slurry gasification technology with a capacity of 3,000 t/d or more, to achieve low investment, stability, long operation cycles, larger scale, compatibility with a wide range of coal types, and reduced consumption. Various modern gasification technologies should achieve new breakthroughs and developments in key areas such as wastewater treatment, waste residue recycling, and the reduction of high-concentration brine. Overall coal gasification should be integrated with coal chemical industry, combined cycle power generation, and large-scale ultra-supercritical power generation ； Significant breakthroughs are needed in the combined application of coking, low-temperature pyrolysis, and various gasification technologies, as well as in the integration of pollution control techniques, including efficient dust removal, sulfur recovery, and denitrification technologies ； Wastewater treatment technologies such as phenol-ammonia recovery, wastewater pulping, and activated carbon adsorption ； Coupling technologies such as combined cycle power generation and large-scale supercritical power generation ； Significant breakthroughs are needed in pollution control technologies such as coking, low-temperature pyrolysis, and the combined use of various gasification techniques. It is necessary to develop core upgraded technologies for clean coal gasification that possess independent intellectual property rights in areas such as efficient dust removal, desulfurization, denitrification, phenol and ammonia recovery, wastewater pulping, activated carbon adsorption for wastewater treatment, as well as technologies for large-scale gasifiers, pyrolyzers, synthesis towers, and waste heat boilers. 4.7 Large-scale syngas purification technology series: Based on the absorption and integration of domestic and international gas purification technologies, innovative integration has led to the development of large-scale syngas purification technology with independent intellectual property rights. Upgrade and improve the aspects related to the conversion process, such as: (1) Developing large-scale technologies for the conversion of gases containing high levels of carbon monoxide, enhancing the activity and service life of sulfur-resistant, wide-temperature range conversion catalysts; optimizing the integration to accommodate various process parameters associated with the production of clean syngas from gasification, meeting the different requirements of various products regarding conversion processes; increasing the rate of carbon monoxide conversion, reducing steam consumption and energy use, and lowering investment costs ； (2) Carbon dioxide removal technology: Develop large-scale low-temperature methanol washing processes capable of purifying syngas to produce over 1 million tons of alcohol per year, thereby creating low-temperature methanol washing processes suitable for large-scale carbon dioxide removal, along with the corresponding large-scale absorption towers and other equipment. Coupling and integration technologies of various purification process techniques, as well as the comprehensive utilization of carbon dioxide for oil and gas displacement. Large-scale air separation technology with a capacity of over 70,000 m3/h, as well as technology for large domestic gas compressors, cycle gas compressors, and large-scale mechanical equipment ； (3) Develop desulfurization and sulfur recovery technologies, as well as carbon monoxide and carbon dioxide separation technologies, to meet the gas separation requirements for different products, scales, and composition profiles through a combination of processes such as adsorption, PSA, membrane separation, and low-temperature distillation. 4.8 Large-scale methanol synthesis technology: The synthesis process characterized by isothermal synthesis using by-product steam is the mainstream development in methanol synthesis technology. The development of large-scale methanol synthesis technology should focus on the following aspects: (1) Adopting the methanol synthesis reactor process featuring multiple adiabatic sections and inter-section heat exchange, mastering the process design for two towers in series, making progress in scaling up methanol reactors, and breaking through the limits of maximum scale ； (2) The methanol synthesis reactor process with inter-stage quenching during digestion and absorption reduces the energy consumption for methanol synthesis while enabling larger scale operations ； (3) Research and develop a pilot-scale unit for slurry-bed methanol synthesis reactors to improve the heat transfer capacity of methanol reactors and extend the catalyst life. Conclusion: During the 12th Five-Year Plan period, technological innovation has always been a key factor in the development of modern coal chemical enterprises, and it will undoubtedly remain a top priority during the 13th Five-Year Plan period as well. Technological innovation lies not only in original inventions but also in the integration of technologies with significant practical value. By integrating and reorganizing individual coal chemical process technologies, engineering technologies, information technologies, and environmental protection control technologies, a completely new set of upgraded technologies with unified overall functionality is developed, with the aim of creating a new brand for modern coal chemistry. Under the new normal, modern coal chemical industry will face more, greater, and tougher new challenges. However, it will also encounter potential strategic opportunities, thus making positive contributions to China’s oil and chemical industry as it undergoes a leapfrog development from being a major player to becoming a leading power in the field.