The gasification plant of Shaanxi Chemical completed the planned major maintenance work on the gasification furnace

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Shaanxi Shenhua Gasification Plant completed the planned major overhauls of its gasification furnaces. Author/Source: Shaanxi Shenhua Coal Chemical Group Co., Ltd. Date: 2022-01-04. Clicks: 16. Throughout 2021, 11 such major overhauls were carried out on the gasification furnaces; the longest operating time for a single furnace was 73 days. Key performance indicators such as coal consumption per ton of ammonia produced, oxygen consumption, and slurry concentration all reached the best levels in the company’s history. There were no safety incidents throughout the year, which laid a solid foundation for the successful achievement of the company’s annual safety targets. In 2021, the gasification plant achieved advanced levels compared to its peers in key areas such as the further concentration of water-coal slurry and the extension of the operating cycle of the gasification furnace’s burners; the operating cycle of these burners was extended by 5 days compared to the previous year. This demonstrated a significant exemplary effect, helping to drive continuous progress in all aspects of the plant’s operations. Maintenance quality is a prerequisite for the safe and stable operation of production systems. In 2021, the gasification plant strictly controlled maintenance plans and the processes involved, ensuring high quality standards and not tolerating any quality issues. From January to November, Reactors A, B, and C were put into operation 16 times. Eleven gasification reactors were scheduled for major or medium-scale maintenance, with 4 instances of continuous operation; no quality incidents occurred at any point. The average stable operating period for the gasification reactors was 55.6 days, with the longest individual operating time reaching 73 days ； Compared to the same period in 2020, the average stable operation period has increased by 1 day, and the maximum operating time per unit has increased by 5 days ； The overall system stability in the purification section is better than in previous years; 706A operates at 155,000–160,000 Nm3/h, while 706B operates at 165,000–168,000 Nm3/h. This ensures a high level of production throughout the year. In 2021, efforts were made to advance benchmarking work in four areas: production management, equipment management, safety and environmental management, and team benchmarking. Through thorough benchmarking, the overall level of management improved steadily, with various benchmarking indicators showing continuous improvement; some of these indicators have even reached the benchmark values. In particular, indicators such as coal consumption per ton of ammonia produced, oxygen consumption, and slurry concentration have all reached the best levels in the company’s history. From January to October, the average coal consumption per ton of ammonia was 1377.5 kg/tNH3, a decrease of 6.9 kg/tNH3 compared with the previous year ； The average oxygen consumption was 737.6 Nm3/tNH3, a decrease of 6 Nm3/tNH3 compared to the previous year ； The average coal slurry concentration was 62.93% (compared to 62.52% in the same period of 2020), representing an increase of 0.4% on a year-on-year basis. In terms of technological upgrades, it is necessary to unlock the potential of existing equipment to achieve efficient and low-consumption operation. The gasification plant has adopted equipment technological upgrades as an effective means to improve energy efficiency. By initiating and implementing technical improvement projects in a scientific manner, it completed the replacement of the gas-liquid distributor in the T1501 stripping tower; as a result, energy consumption and the ammonia content at the bottom of the tower were significantly reduced ； The sealing grade of the self-regulating valves PV15005/25005 in the purification section was upgraded, resulting in savings in usable gas ； After upgrading the electro-hydraulic actuators at the inlet and outlet of the 710 sulfur recovery heat and cold fans to electric actuators, the long-standing problems of oil leakage and difficult operation were completely resolved ； The material of the internal components in the three heat exchangers E1618/1702/1620 was changed, resolving the issue of frequent internal leaks ； After the upgrade of the vent valves PV15005/PV25005 at the outlet section of the conversion unit (705AB), the sealing grade was improved from IV to V, resulting in a savings of at least 200 standard cubic meters of conversion gas per hour, and generating an annual benefit of at least 800,000 yuan ； Regarding the management of the grinder lubrication system in the gasification section, through technical upgrades to the grinders and measures such as adding additional filler rods, the pulp production capacity and efficiency of the grinders were improved, enabling the coal slurry concentration to be maintained above 62.8% on a continuous basis, which laid the foundation for stable and high-level production of the system. This work has reached a leading level among peers in terms of water-coal slurry concentration; experience gained was shared at the national annual conference on water-coal slurry gasification processes and equipment technology, and the overall efforts were recognized by the experts and peers present. To address the issue of high consumption, the gasification plant took measures such as improving ash water treatment, ensuring high quality in the maintenance and cleaning of individual furnaces, upgrading the burners used in the process, increasing the concentration of coal slurry, controlling the temperature of the gasification furnace appropriately, raising the effective gas components in the process gas, and increasing the temperature of the gas at the exit of the process unit. Through repeated experimentation and strict management, consumption was effectively brought under control. From January to November, Caojiatan, Hongliulin, and Ningtiaota were used in a proportionate mixture for combustion; Caojiatan and Ningtiaota were also used together in a proportional manner. Although the type of coal changed frequently, the overall production process remained relatively stable ； The waste coal slurry recovery unit in Section 702 was kept in operation to recover BDO-aldehyde-containing wastewater and butanol wastewater, which were then mixed and used in combustion at low flow rates; this contributed positively to the company’s overall environmental protection efforts as well as its initiatives to save energy and reduce consumption.