What is the operating status of the purification equipment associated with fixed-bed gasification, and what are the bottlenecks and solutions?

Purification devices for fixed-bed gasification often face certain bottlenecks, such as high levels of tar and dust, as well as insufficient efficiency in gas cooling and cleaning. To address these issues, the following measures can be taken: 1. Employ more efficient tar cracking technologies, such as increasing the supply of secondary air or using catalysts, to reduce tar formation. 2. Optimize dust collection equipment, such as by using more efficient filtration systems or electrostatic precipitators. 3. Improve the gas cooling and washing systems to ensure that the gas is thoroughly cleaned and cooled before it is used in subsequent processes. Through these measures, the operating efficiency and gas production quality of the purification unit in fixed-bed gasification can be effectively improved. .

The purification units associated with fixed-bed gasification may encounter certain bottlenecks during operation, and these bottlenecks stem mainly from the characteristics of the gasification process itself as well as the technical level of the purification units. The following is a detailed analysis of these bottlenecks along with corresponding solutions: I. Bottleneck Analysis – Low efficiency in the recycling of gasification by-products. Problem: A large amount of by-products are generated during the gasification process, such as biochar and biomass extracts. If these by-products are not recycled, they will not only reduce the efficiency of biomass utilization but also cause environmental problems. The technology for gasification equipment is not yet mature. Problem: Fixed-bed gasification technology is primarily designed for small to medium-scale applications, and it suffers from a low level of mechanization and automation. This results in the need for a large amount of manual labor to operate at the top of the furnace during operation, which not only endangers the safety of the operators but also increases operational and maintenance costs. In addition, the gas produced by updraft fixed beds contains a large amount of tar, which places a heavy burden on the gas purification system and easily causes blockages in pipelines and valves. Low gas generation efficiency and poor adaptability to various coal types: The fixed-bed gasification technology has relatively low gas generation efficiency and poor adaptability to different coal types. This limits its use in certain application scenarios. II. Solutions: Improving the efficiency of resource utilization of gasification by-products. Measures: Transforming gasification by-products into valuable products through the development of more efficient resource utilization technologies. For example, biochar can be used for soil improvement or as fuel, while biomass extracts can be used to produce chemicals or fertilizers, among other things. Measures to improve gasification equipment technology: Develop more advanced fixed-bed gasification equipment to increase the level of mechanization and automation, thereby reducing labor costs and maintenance expenses. Optimize the control of the gasification process to improve gasification efficiency and stability. Improve the gas purification system to enhance tar filtration efficiency and reduce blockages in pipelines and valves. Improve gas production efficiency and adaptability to various coal types. Measures: Enhance gas production efficiency by developing more efficient gasification catalysts or improving the gasification process. Conduct research on the gasification properties of different coal types, optimize gasification parameters, and improve the adaptability of various coal types. Environmental improvement measures: Environmental improvements are carried out to address the pollutants generated during the fixed-bed gasification process. For example, the closed-loop technology for cooling water in the gas generation process is employed to address the issue of volatile pollutants escaping into the atmosphere ； A bag filter is used to capture fly ash in the water-gas mixture and mix it for combustion, thereby eliminating dust, wet slag, and on-site odors. III. Conclusion: The purification systems used in fixed-bed gasification may face challenges such as low efficiency in the recycling of gasification by-products, immature technology for the gasification equipment, low gas production efficiency, and poor adaptability to different coal types during operation. To address these bottlenecks, measures such as improving the efficiency of resource utilization of gasification by-products, upgrading gasification equipment technology, enhancing gas production efficiency and coal type adaptability, as well as carrying out environmental protection upgrades, can be taken. The implementation of these measures will help improve the overall level and market competitiveness of fixed-bed gasification technology.

This post was last edited by pzhmotor on 2024-11-4 at 09:49. The biggest problem with the purification system is the safe operation of the electrostatic precipitator. GB6222 stipulates that the oxygen analyzer must be installed at the inlet of the electrostatic tar precipitator. However, due to the high tar content in the raw coal gas, the probe often gets clogged, rendering the electrostatic tar precipitator inoperable. An optical opposed-type oxygen analyzer and nitrogen positive-pressure purging must be used to ensure the proper operation of the oxygen analyzer. Oxygen meters based on the aspiration sampling principle cannot meet the operational requirements. Blockages also occur easily in scrubbers and desulfurization tower packings, as well as at the elbows of inlet and outlet pipes. Flushing pipes can be installed at the top of the purification tower and at the bends in the pipelines to carry out flushing on a regular basis. As a side note: the atmospheric pressure fixed-bed gasification process has been classified as obsolete (single-stage) and restricted (two-stage), while pressurized gasification is also showing a trend of being replaced by fluidized bed technology. Apart from objective factors such as heavy labor intensity, difficulty in sourcing raw materials, high costs, and the challenge of meeting safety and environmental inspections, the high residual carbon content in ash and poor economic viability are even more intractable problems. If possible, it’s better to change the process. PS: Some former colleagues and suppliers who went to Southeast Asia and Africa have mostly returned in recent years. The manufacturers in China that used to be the best at producing fixed-bed reactors now also focus on fluidized-bed gasifiers.

The main problems are long processes, high power consumption, high operational risks for reciprocating compressors, and difficulties in treating desulfurization wastewater