What are the problems with the gasification in the three coal-to-gas projects that are already in operation? How was it solved?

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What are the problems with the gasification in the three coal-to-gas projects that are already in operation? How was it solved? Author/Source: Liu Fengli, Bi Jiali (Saiding Engineering Co., Ltd.) Date: 2017-06-20 Clicks: 98 Gasification technology is the cornerstone for the development of coal chemical industry. In the past, China’s large-scale gasification technologies were heavily dependent on foreign sources. Major gasification technologies such as those from Lurgi, Texaco, GSP, and Shell were introduced to China, but the technologies that were copied and transplanted there often failed to adapt to local conditions, resulting in various problems during implementation and affecting normal operational activities. Drawing on its own strengths and building on the introduction, digestion, and absorption of foreign technologies, Saiding Engineering Co., Ltd., in collaboration with research institutions, material and equipment manufacturers, as well as renowned experts in the industry, and by pooling a team of engineering and technical personnel, has developed various types of \"Saiding furnaces\". Since the late 1990s, it has completely replaced foreign Lurgi furnaces in the domestic market. 1. The development history of Sideng furnaces 1.1 The development history of coal gasification under pressure abroad: The Lurgi coal gasification furnace was once the world’s earliest and only industrially applied method for coal gasification under pressure; the West German company Lurgi installed the first such gasification unit in 1936. It went through the first generation of furnace types in the first phase (1930–1954), and the second generation of furnace types in the second phase (1952–1965) ； Stage 3 (after 1969): The third generation of furnace designs. This generation **improved the capacity of the gasification furnace and expanded the range of coal types that could be used, in order to meet the needs of modern large-scale factories. The inner diameter of the furnace is 3.8 meters; it features a double-layer jacketed shell, with no refractory bricks lining the inner walls. The furnace is equipped with a rotating coal distributor and a stirrer, and its gasification capacity is 50,000–55,000 Nm3/h of raw gas. Currently, the third-generation reactor types are the main ones being built and operated worldwide. After the 1980s, as oil and gas prices declined, Luchi Company gradually divested its coal chemical business, and development of this technology abroad also came to a standstill. 1.2 Overview of the application and optimization adjustments of Luchi furnaces in domestic projects 1.2.1 Tianji Fertilizer Plant – Raw coal type: low-quality coal ； Main products and capacity: Synthetic ammonia 30×104 t/a, 52×104 t/a ； Commissioning date: 1987 ； Gasifier specifications: Φ3.842m, 3.0MPa(G) ； Number of gasifiers: 4+1 (of which 4 are imported; the fifth is domestically produced) ； Current operation status: Normal. Luchi Pressure Gasification has extensive experience in gasification using lignite and long-flame coal as raw materials. The Tianji Fertilizer Plant in China used lean coal as the gasification feedstock, marking the first instance in the history of Lurgi pressure gasifiers. During the first few years of trial production, gasification issues disrupted the continuous and stable operation of the ammonia synthesis plant. Drawing on production practices, the factory made roughly 400 improvements and innovations to the originally imported processes. The main improvements for Luchi gasification are as follows: a) By studying the gas distribution method on the grate, the optimal gas distribution scheme suitable for lean coal was proposed and tested. b. By studying the particle size distribution of the raw coal, the optimal particle size distribution suitable for lean coal was proposed and tested. c. The structure and materials of vulnerable components in pressurized gasification of coal, such as the ash lock upper and lower valves, were specifically optimized and modified, enabling long-term operation. The additional fifth gasifier was added because the existing 4 gasifiers were unable to meet production targets and standards. The addition of the fifth gasifier was also approved by Lurgi at that time to be added independently within China. The design, manufacturing, construction, and commissioning of the 5th gasification furnace were all completed independently in China. 1.2.2 Harbin Gasification Plant – Raw coal type: long-flame coal ； Main products and scale: Urban gas at 160×104 Nm3/day, with methanol production of 4×104 t/year ； Commissioning date: 1993 ； Gasifier specifications: Φ3.842m, 3.0 MPa(G) (lined at the time of import) ； Number of gasification furnaces: 4+1 ； Current operating status: Normal. In the later phase, the main improvements made to the Lurgi gasifier are as follows: a) The originally designed gas distribution failed to meet the gasifier’s production capacity. By altering the diameter of the gas distribution elements, the distribution rate and flow velocity of the gasifying agent were adjusted, resulting in more uniform gas distribution across the grate; this **increased the gasifier’s production capacity** (the PKM system features three layers of gas distribution). b. The pressure-relief gas from the original coal lock design, as well as the gas released during startup and shutdown, is vented after washing. To protect the environment and recover useful components, a coal lock gas recovery system was added as part of the technical upgrades. c. The original gasifier design featured a refractory lining structure; however, the installation of this lining reduced the effective volume of the gasifier and also made wall deposition more likely to occur. Later, the owner and SDIC Engineering jointly verified and decided to eliminate the refractory bricks; they also corrected the overall thermal compensation within the gasifier, etc. 1.2.3 Yima Gasification Plant, Phase I Raw coal type: long-flame coal ； Main products and scale: Urban gas 120×104 Nm3/day, methanol produced concurrently 4×104 t/year ； Commissioning date: 2001 ； Gasifier specifications: Φ3.842m, 3.0MPa(G) ； Number of gasification furnaces: 2+1 ； Current operating status: Normal. The main improvements made later on for the Luchi gasification process are as follows: a) By studying the particle size distribution of the feed coal, the optimal particle size distribution suitable for long-flame coal was identified and tested. 1.3 Development history of domestic pressurized solid slag discharge gasification for coal crushing. Since the 1970s, Saiding Engineering Co., Ltd. has collaborated with German companies such as Lurgi and PKM to design synthetic ammonia plants for Tianji Group, gas projects in Yilan, Harbin, and gasification projects in Yima, thereby accumulating extensive experience in engineering design and construction. “During the “Seventh Five-Year Plan” and “Ninth Five-Year Plan” periods, under the organizational leadership of **, the scientific and technological research project titled “Basic Design for a Lurgi Coal-Crushing Pressure Gasification Plant Capable of Producing 1 Million Cubic Meters of City Gas per Day” was completed. On this basis, the design and construction of the Taiyuan furnace were independently carried out. Thus, the domestically developed \"coal crushing pressurized gasification technology\" has entered the stage of application. In 1991, the Science and Technology Commission awarded the Second Chemical Research Institute a certificate recognizing it as an advanced collective for its work on the key scientific and technological project during the \"Seventh Five-Year Plan\" period (the task force responsible for the ф2.8m pressure gasification furnace). Based on the Φ2.8m gasifiers with a pressure of 2.0 MPa, and taking into account the expansion and renovation experience of Tianji Group (formerly Shanxi Fertilizer Factory), Saiding Engineering Co., Ltd. developed and designed Φ3.8m gasifiers with a pressure of 3.0 MPa. These were put into use at Shanxi Fertilizer Factory in April 1996 as an addition to the existing equipment. This coal pulverization pressurized gasification furnace uses entirely domestic materials, and its design is equivalent to the third-generation Ruichi Mark IV. The furnace was completed in December 1998, operates smoothly, and has met the design specifications. In 2004, two Φ3.8m gasification furnaces with a pressure of 3.0 MPa were successfully applied in the second-phase construction of the Yima Gas Plant in Henan. The successive completion and commissioning of these facilities mark the full adoption of domestic technology and equipment, and it is also the beginning of the widespread use of such domestic technologies. In recent years, Saiding Engineering Co., Ltd. has developed a coal pulverization pressurized gasification furnace with a diameter of Φ3.8m and a pressure of 4.0 MPa, which is used in the Datang Kesikteng coal-to-natural gas project in Inner Mongolia, the Qinghua coal-to-natural gas project in Xinjiang, as well as other ongoing projects related to coal-to-gas, ammonia synthesis, and methanol production. Among them, the Inner Mongolia Datang Keshiketeng coal-to-natural gas project and the Xinjiang Qinghua coal-to-natural gas project have been successfully commissioned. On December 23, 2013, the first batch of natural gas produced by the Inner Mongolia Datang Keshiketeng coal-to-natural gas project was successfully integrated into Beijing’s gas distribution network. It marks the world’s first 4.0 MPa coal pulverized pressurized gasification furnace that was designed, built, and successfully operated. At present, to meet the needs of large coal chemical manufacturing enterprises in our country, Saiding Engineering Co., Ltd. is undertaking a 863 project funded by the Ministry of Science and Technology. It has developed a coal gasification furnace with a diameter of Φ5.0m and a pressure of 6.0 MPa. A demonstration unit of this type was built jointly in Yima, Henan Province. Currently, the non-standard equipment for this project is being purchased, and the on-site construction work is in progress; commissioning is expected to be completed by 2017. Saiding Engineering Co., Ltd. built the laboratory for pressurized fixed-bed gasification with the highest pressure in China at Qinghua. The design pressure of the gasifier is 8.0 MPa, with an inner diameter of 0.2 m. The laboratory has now been built and is in trial operation. It is capable of conducting small-scale testing and combustion tests on various types of coal, collecting data at different pressures, carrying out CO2 recycling tests, and sampling data from different reaction stages for analysis and regression. Key milestones in the development of pressurized solid-solid slag discharge gasification using crushed coal in China: In the 1970s, negotiations began at the Shanxi Fertilizer Factory to introduce this technology. From 1980 to 1985, it was part of the key scientific and technological research project during the “Sixth Five-Year Plan” period, titled “Scientific and Technological Research on Φ2.8m Pressurized Gasification Furnaces”. From 1986 to 1990, it was included in the key research projects under the “Seventh Five-Year Plan”. The Φ2.8m gasification furnace went into operation in 1986; the Tianji plant also started operating in the same year, and after ten years of steady operation, continuous improvements were made to it. In 1991, the key scientific and technological research project under the Seventh Five-Year Plan was completed, and the team received a collective award for scientific and technological progress. In 1993, the PKM furnace at the Harbin Yilan Gas Plant went into operation, earning a silver award for scientific and technological progress. In 1995, the fifth furnace at the Tianji plant was designed using domestically produced components. On December 17, 1998, the domestically produced furnaces at Tianji plant began operating. In 2000, the Yima Gas Plant started operating. In 2004, the third furnace at Yima was built entirely with domestically produced components. In 2006, the second phase of the Yima plant was put into operation (also using entirely domestically produced components). In 2008, the Shanxi Lu’an Coal-to-Oil project started operating. In 2009, the SD 5000 gasification furnace project was initiated by the company. In 2010, the Guodian Chifeng 3052 project went into operation. In 2012, the Xinjiang Guanghui plant began producing 1.2 million tons of methanol per year. In 2013, the Datang Keqi Coal-to-Natural Gas project was launched (it featured the world’s first 40-kilogram gasification furnace). In 2014, the Xinjiang Qinghua Coal-to-Gas plant started operating. In 2015, the Henan Jinmei Qing plant began operating. The SD 5000 gasification furnace project was included in the Ministry of Science and Technology’s “863” program under the title “Large-Scale Pressurized Gasification Technology and Demonstration”. Construction of the gasification plant in Yima began, with trials expected to start in 2017. 1.4 Overview of domestic-designed and constructed projects for pressurized gasification using crushed coal. 1.4.1 Second phase of the Yima Gas Plant: Raw coal type – long-flame coal ； Main products and scale: Urban gas: 144×10^4 Nm³ ； Commissioning date: 2006 ； Gasifier specifications: Φ3.842m, 3.0MPa(G) ； Number of gasification furnaces: 2 ； Current operation status: Normal. Version 1.4.2 – Shanxi Lu’an coal-based synthetic oil; raw coal type: lean coal ； Main products and scale: 160,000 t/a of synthetic oil ； Commissioning date: 2008 ； Gasifier specifications: Φ3.842m, 3.0MPa(G) ； Number of gasification furnaces: 6 ； Current operating status: Normal. Version 1.4.3, Jinmei Jinshi ammonia synthesis plant; type of coal used as raw material: anthracite ； Main products and production scale: hydrogen 4.5×104 t/a, methanol 20×104 t/a, **40×104 t/a ； Commissioning date: 2013 ； Gasifier specifications: Φ3.842m, 3.0MPa(G) ； Number of gasifiers: 6+2 ； Current operation status: Normal. It is the first time in China that a coal gasification unit using crushed coal, with Jinmei anthracite as the designed coal type, has been used to produce synthetic ammonia feed gas. Anthracite has a low volatile matter content; in actual production, no by-product oil was recovered, which creates conditions for optimizing downstream gas water treatment facilities. Both the actual load of the gasification furnace and the composition of the effective gas in the project have exceeded the design values. 1.4.4 Jinmei Tianqing ammonia synthesis (4.0 MPa, anthracite) Raw coal type: Anthracite ； Main products and production scale: hydrogen 4.5×104 t/a, methanol 20×104 t/a, **40×104 t/a ； Commissioning date: 2013 ； Gasifier specifications: Φ3.842m, 4.0MPa(G) ； Number of gasification furnaces: 6 ； Current operating status: Normal. The designed load for each gasifier is 7,500 Nm3/h. As the load per gasifier increased to 9,000 Nm3/h, the temperature of the raw syngas at the gasifier outlet rose by approximately 20°C. The gas output per gasifier also increased from 45,000 Nm3/h to 54,000 Nm3/h, while the coal feed rate per gasifier went up by 10.0 tons/hour. Compared to other coal types, Jincheng anthracite used in 4.0 MPa pulverized coal pressurized gasification features a high gas yield per unit, low specific consumption, and a low operating frequency of ash-lock valves. It is an excellent coal type for the development of coal chemical products. 1.4.5 Inner Mongolia Datang International Keshiketeng Coal-to-Natural Gas Project: Raw coal type – lignite ； Main products and scale: 4.0 billion Nm3 of SNG per year ； Commissioning date: 2012 ； Gasifier specifications: Φ3.842m, 4.0MPa(G) ； Number of gasification furnaces: 48 (16 in Phase 1 are already in operation) ； 16 units in Phase 2 have been completed) ； Current operating status: Normal. The raw coal and fuel coal used in this project are both Victory Coal No. 5 from the Shilinhot Victory Coalfield. The quality of the raw coal is that of a lignite with low sulfur and ash content, as well as high volatility. The raw material contains 32% moisture, 13.8% ash, and 32.8% volatiles. This project was the world’s first coal gasification furnace with a pressure of 40 kg/cm2, and it successfully produced qualified natural gas on July 28, 2012. All performance indicators of the gasification furnace meet or even exceed the design requirements. 1.4.6 Others There are also projects that are already in operation: Xinjiang Guanghui New Energy Co., Ltd. (methanol: 120×104 t/a, dimethyl ether: 80×104 t/a) ； Guodian Chifeng 3052 Project ； Xinjiang Qinghua Coal-to-Natural Gas Project Phase I ； For the projects that have been completed and are ready for operation, such as the China Coal Pingshuo Low-Quality Coal Demonstration Project, the Xinjiang Xinye Energy Methanol Project, the Datang Fuxin Coal-to-Natural Gas Project (Phase I), and the Yili Xintian Coal-to-Natural Gas Project, no further detailed information on their operational data will be provided. 2. Application of the Sidinger furnace in coal-to-natural gas production: The advantages of the fixed-bed pressurized gasification process technology are that it is mature, advanced, and reliable; moreover, it requires the least investment among large-scale coal gasification plants. Oxygen consumption and coal consumption in pressurized gasification of pulverized coal are lower than those in other coal gasification methods. The pressurized gasification of coal to produce natural gas has the following main advantages: (1) The amount of methane produced during the coal gasification process is approximately 45% of the total methane content in natural gas; in other words, 45% of the methane is generated within the gasifier. This reduces the load on methane synthesis and improves the thermal efficiency of the coal-to-natural gas process. (2) The heat released from the formation of methane during coal gasification can provide part of the reaction heat required for this process, thereby reducing the coal and oxygen consumption in coal-to-natural gas production. (3) Pressurized gasification of coal is a gasification process that combines coal dry distillation with semi-coke gasification; it enables the recovery of some organic compounds from coal, yielding alternative products for the petrochemical industry. (4) Pulverized coal pressurized gasification technology is mature, simple to operate, and requires the lowest investment. It also has the lowest oxygen consumption among all large-scale coal gasification processes, as well as the least investment in air separation equipment and the lowest operating costs. (5) It has strong adaptability to different types of coal; almost all coal types can be gasified using it, especially low-quality coals with high moisture content, high ash content, and high ash fusion point. It is not restricted by the slurry-forming properties of the coal, which is a key factor in reducing the production costs of SNG products. The advantages of the fixed-bed pressurized gasification process technology are its maturity, advancement, and reliability; it also results in a high methane content in the gas, making it ideal as a fuel gas. It requires the least investment in large-scale coal gasification plants. The coal-to-natural gas process developed by Saiding Company uses low-quality lignite as raw material. In the selection of gasification process technologies, a detailed analysis and comparison were conducted on all the parameters relevant to brown coal gasification technologies, including process characteristics, gasification temperature and pressure, coal feed rate, size of each furnace, lifespan of key components, number of gasifiers, dust removal and cooling methods, land area required by the facility, coal consumption, oxygen consumption, electricity consumption, steam consumption, carbon conversion rate, gasification thermal efficiency, and investment costs. The highest difference in consumption metrics among several gasification processes is 19 times, while the highest difference in investment costs is 2.6 times. The investment for fixed-bed coal crushing pressurized gasification is only 1/2 to 1/3 of that for fluidized-bed gasification, while the power consumption is only 1/10 to 1/20 of that for fluidized-bed gasification. Meanwhile, fixed-bed pressurized gasification enables the co-production of coal-derived natural gas, methanol, dimethyl ether, ammonia, etc., offering better economic benefits and stronger risk resistance. The domestically produced coal slurry pressurized gasifiers feature low construction and maintenance costs; extensive experience has been accumulated in their design, manufacturing, construction, and operational management. Introducing a gasification furnace not only requires high investment but also entails costly patent fees, technology transfer fees, the manufacturing of specialized equipment, on-site technical services, as well as various bundled sales. At the same scale, domestic coal gasification under pressure requires an investment that is more than 50% lower compared to imported gasification technologies. 3. Optimization and improvements of the Sidu furnace in coal-to-natural gas projects
3.1 Problems and solutions during the operation of Datang Keqi’s coal-to-gas project
The 4 billion Nm³/year project undertaken by Inner Mongolia Datang International Keshiketeng Coal-to-Natural Gas Co., Ltd. (hereinafter referred to as “Keqi Company”) is being constructed in three series, with each series comprising 16 coal slurry pressurized gasifiers operating at 4.0 MPa. The first series was put into operation at the end of 2013. The 4.0 MPa coal-crushing pressurized gasifier at the Keqi Company is among the first of its kind to be used in China; it uses low-quality lignite (with a high moisture content of Mar: 36.9% and a low calorific value of Qnet,ar: 13.98 MJ/kg) as feedstock, which is also quite rare in China. Additionally, since the bulk density of the lignite from Inner Mongolia’s Datang Dongshengli mine is relatively low—averaging 650 kg/m³—and its reactivity is quite high, multiple calculations, analyses, and evaluations were conducted during the engineering design phase to address the issue of excessively frequent coal feeding. As a result, the height of the coal lock was increased by 1.3 meters, thereby expanding its volume from 12.3 m³ to 18.7 m³. At the same time, considering the compatibility between the volume of the coal lock and that of the gasifier, the height of the gasifier was also increased by 0.5 meters, raising its volume from 98 m³ to 103.8 m³. At the same time, it is taken into account that increasing pressure can raise the methane content in the raw gas, which helps to reduce the amount of dust carried away. In this project, the operating pressure of the gasifier is increased from the original 30 kg/cm² to 40 kg/cm². The first gasifier in Inner Mongolia’s Datang International Kesikteng coal-to-gas project was successfully commissioned on August 26, 2011. On July 28, 2012, qualified natural gas was successfully produced. The world’s first 4.0 MPa coal pulverized pressurized gasification furnace was successfully put into operation, proving that such a furnace is feasible; key equipment such as the furnace body, coal lock, and ash lock also withstood practical operational testing. Due to the youth and instability of the Dongshengli lignite in Inner Mongolia of Datang, various problems unprecedented at the beginning of operation were encountered. The main issues are as follows: 1) Due to the extremely high activity of the coal used by Datang Dongshengli, frequent coal feeding is required during operation, with the maximum coal feeding rate reaching around 1,000 tons per day – a level that has never been seen in coal gasification using pressurized air. This imposes very high demands on the design and control of the coal feeding system. During operation, various optimization measures were employed to enable the gasifier to operate at a 120% oxygen load normally. 2) By taking into account the properties of the raw coal and the operational experience gained during the commissioning period, the diameters of the gas distribution holes and the way in which gas is distributed across the four layers were adjusted. This resulted in a more rational arrangement of gas distribution holes on the grate, greater uniformity in their distribution, improved stability of the bed layer, an increase in the production capacity of the gasifier, enhanced operational flexibility, better stability during operation, reduced energy consumption, and a decrease in the carbon residue level from 8% to below 5% ； At the same time, the comparative test run with steam and oxygen showed a significant reduction, which increased the steam decomposition rate and reduced wastewater. 3) At the end of November 2013, after the gasification furnaces at Keqi Company were put into operation, leaks occurred in the jackets of multiple furnaces within a very short period of time. Through the analysis of the corrosion mechanism, it is preliminarily believed to be a comprehensive corrosion primarily caused by alkali metals, which is the first time such a phenomenon has been encountered in the history of coal gasification using pressurized gas. Subsequently, through various analyses, 3–5 mm of Inconel 625 material was cladded on the thinned (leaking) area of the gasifier jacket (made of 15CrMo/20R material). Production was resumed on April 2, 2014, and to date there has been no significant thinning in the aforementioned area, indicating that this method can resolve the problem of jacket thinning (leaking) in gasifiers. The 4.0 MPa coal pulverization pressurized gasification furnace of Keqi Coal-to-Natural Gas Company can operate continuously for 241 days per unit, and the minimum amount of coal required for gasification is gradually decreasing, along with a gradual reduction in the steam-to-oxygen ratio. 3.2 Problems and Solutions in the Operation of Xinjiang Qinghua Coal-to-Gas Project The Xinjiang Qinghua coal-to-natural gas project is the first coal-to-natural gas project approved in the Xinjiang region. The quality of the raw coal used in Xinjiang Qinghua differs fundamentally from that used by Datang Keqi. This is mainly reflected in the low falling strength of the raw coal (66%) and its relatively poor thermal stability. The biggest problem associated with pressurized gasification using pulverized coal is the severe fragmentation of lump coal during transport on conveyor belts, which results in the particle size of the coal feed to the gasification furnace exceeding the specified limit. As a consequence, the crude gas produced during gasification contains many impurities, leading to blockages in the downstream purification equipment. To this end, given that the traditional on-site gasification coal preparation system is relatively complex and requires a series of processes such as storage, transportation, screening, and crushing. Before being fed into the furnace, gasified coal undergoes multiple transfers; the originally prepared coal has a lump ratio of 3.3, and the problems encountered during the operation of Yili Xintian coal-to-gas project make it impossible to ensure an appropriate lump ratio in the coal fed into the furnace. Saiding Company has carried out a large number of effective technical upgrades and optimizations to the raw coal transportation system using methods such as computer simulation. The chute is modified into a curved shape, so that there are no impact points within the chute, and the material flow falls along the sides of the chute. At the same time, the material flow velocity is effectively controlled; after being discharged from the vibrating screen, it moves toward the receiving conveyor belt at a relatively uniform speed, in a spiral downward pattern. The advantages of the renovation are as follows: Advantages: Minimizes the block breaking rate to the greatest extent ； Minimize chute wear to the greatest extent possible ； Maximize protection for the belt ； Minimize deviation as much as possible ； Minimize dust emission to the greatest extent possible. Yili Xintian Coal-to-Natural Gas is another large-scale coal-to-natural gas project in Xinjiang region. Xintian Coal Chemical is currently the world’s largest single coal-to-gas **pilot project that has been completed. On March 29, 2017, Line A of Yili Xintian Coal Chemical Co., Ltd.’s project for producing 2 billion cubic meters of coal-derived natural gas per year was brought online successfully, generating qualified natural gas that was successfully connected to the Yining station of the West-East Gas Pipeline Project, setting a new record for the commissioning of large-scale coal-to-gas projects. The Yili Xintian project has fully drawn on the experiences and lessons learned from the previous two coal-to-gas projects, and carried out extensive optimization and technical upgrades tailored to the quality of the raw coal used in this project as well as its process flow. The main points are as follows: 1) The raw coal conveying system adopts curved coal drop pipes based on the successful experience of similar projects, and effective measures such as steam spraying for dust suppression are used, which significantly reduces the rate of lump coal fragmentation as well as improves the working environment in the workshop. 2) To address the issue of excessive carryover that may occur due to the low strength of the feed coal, various optimization measures were adopted in the gasification section to ensure stable operation of the gasifier and minimize carryover to the greatest extent possible ； At the same time, two sets of dust removal measures for raw gas are connected in parallel before entering the transformation device, thereby preventing the dust contained in the raw gas from affecting subsequent equipment. 3) All components in the gas water treatment section where uncontrolled emissions may occur, such as tank vents and emission sampling ports, are equipped with sealed structures; the emitted gases are collected and sent to the flare system. This thus avoids the problem of uncontrolled emission of gas odors. 4. Future development prospects for the Saiding furnace 4.1 Prospects for the further development of the Saiding furnace Given its unique counter-current bed gasification technology, it features high thermal efficiency ； High methane content is produced during the gasification process ； The characteristics of by-products such as tar, light oil, phenol, and ammonia ensure that the Saiding furnace will have broad prospects for development in the future coal-to-natural gas industry and the graded utilization of coal. 4.2 Advancing towards development that is more advanced, environmentally friendly, and efficient 1) A simplified and greener coal gasification process: Traditional methods for analyzing the composition of crude gas produced by coal gasification involve manual analysis, which leads to delays in obtaining analysis results as well as increased labor intensity. With the optimization and upgrading of the analysis instrument systems, the analysis of crude gas from coal pulverization pressurized gasification can be carried out automatically. This enables the programmed control of processes such as steam heating, air ignition, operation with air, and oxygen cut-off during startup, thereby simplifying the startup process. Additionally, air ignition during the startup process, as well as that during operation, can be completely eliminated with improvements to the control system, and direct oxygen ignition can be used instead, thereby significantly reducing the startup time and the amount of gas released during this period. 2) Collection and utilization of unorganized emissions: The carbon dioxide emissions generated during the pressurized gasification of coal, as well as various other unorganized emissions, are collected together and then processed using regenerative thermal oxidation units. This approach eliminates pollution and unpleasant odors caused by the emissions from the system, while also enabling the production of superheated steam at medium pressure through the use of the waste heat from the flue gases. 3) Hierarchical utilization of energy during the pressurization and depressurization processes in the coal lock: In conventional coal gasification systems using crushed coal, pressurization is carried out using raw coal gas; the gas released during depressurization is stored in a gas holder, and then it is pressurized again by a coal lock gas compressor before being returned to the system. Process configuration has the disadvantages of system complexity and low energy utilization efficiency. The approach of using coal locks for pressure relief and staged utilization offers significant advantages in terms of reducing investment and consumption.