Exploring New Models for Energy Saving and Carbon Reduction — An Interview with Sun Zongli, Chief Engineer of the Chemical Division of China Coal Shaanxi Company

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Exploring New Models for Energy Saving and Carbon Reduction – An Interview with Sun Zongli, Chief Engineer of the Chemical Division of China Coal Shaanxi Company. Author/Source: Sinochem News Network. Date: January 25, 2022. Clicks: 1. Recently, reporters learned from China Coal Shaanxi Yulin Energy and Chemical Co., Ltd. that over the past three years, the energy consumption per unit of output in its chemical division’s olefin production units has decreased by 144 kilograms of standard coal per ton, resulting in energy savings of 480,300 tons of standard coal. Carbon dioxide emissions were reduced by 1,274,300 tons, and production costs were saved by 366 million yuan. The overall energy consumption per unit of olefin output has reached an advanced level in the industry. What strategies does this company use to save energy and reduce carbon emissions? The reporter spoke with Sun Zongli, the chief engineer of the Chemical Division of China Coal Shaanxi Company. 　　Energy conservation and consumption reduction through technological upgrades \"We adhere to technological innovation and energy-saving upgrades in order to improve energy utilization efficiency and reduce energy consumption as well as carbon dioxide emissions.\" ”According to Sun Zongli. 　　For example, by implementing cooling upgrades to the air-cooling systems of steam turbine generators, the exhaust pressure of each unit can be reduced by 3–5 kPa under hot weather conditions; this allows each unit to handle an additional load of around 10 MW, resulting in a yearly reduction of 2,400 tons in coal consumption ； By optimizing reaction conditions in DMTO units, selecting high-performance catalysts, and using techniques such as the pre-deposition of carbon deposits from C4 compounds, it is possible to save 159,000 tons of standard coal per year, thereby reducing carbon dioxide emissions by 413,300 tons ； By adopting third-generation coal slurry concentration technology, the concentration of the coal slurry is increased by 3 percentage points, which allows for a reduction in oxygen consumption of 61.1 million cubic meters per year; this results in savings of 115,500 tons of standard coal, as well as a reduction in carbon dioxide emissions by 300,300 tons. 　　In addition, they carried out more than 50 technical upgrades, including methanol capacity expansion upgrades, modifications to the excess heat boilers in MTO units, technical improvements to gasification deoxidizers, recovery of waste steam from thermal power plants, as well as real-time monitoring of the operating conditions of large-scale units and key pumps. 　　These technological upgrades have achieved significant results in ensuring the stable operation of the equipment as well as in saving energy and reducing carbon emissions. Since the commissioning of its 1.8 million tons per year methanol and 600,000 tons per year olefins plants 7 years ago, the company has maintained stable, safe, continuous, full-capacity operation with excellent performance, setting numerous industry records. Among them, the olefin plant has been in continuous operation for over 1,000 days, making it the coal-to-olefins plant in China with the longest continuous operation time and the most stable production. As product output increases year by year, the energy consumption per unit of product also declines steadily. In 2021, the methanol consumption per ton of \"dienes\" was reduced from 3.049 tons/ton to an optimal level of 2.908 tons/ton. The overall energy consumption for olefin products was 2,856 kilograms of standard coal per ton, resulting in energy savings of 234,000 tons of standard coal, as well as a reduction in carbon dioxide emissions of 608,000 tons. 　　Precise management drives efficiency. Sun Zongli said that the company adheres to giving equal importance to management and energy-saving upgrades, continuously improving its precise energy management level, which serves as another effective tool for saving energy and increasing efficiency. 　　Optimize equipment to save energy and improve efficiency. Efforts are made to improve the energy efficiency of motors, conduct comprehensive assessments of the energy efficiency of pumps and motors, and optimize the power factor in power systems, in order to achieve energy savings and carbon reduction. Optimize the operation mode of equipment, promote the effective utilization of excess steam, and achieve energy savings and reduced consumption. 　　Upgrade of the energy efficiency management system. Establish a scientific and comprehensive set of energy consumption assessment indicators, and conduct regular benchmarking of energy efficiency within the industry. Optimizing the plant’s low-pressure nitrogen system saves 110,000 kWh of electricity per day. By upgrading the existing energy management system and improving the energy information evaluation system, daily balance of production and consumption data for all facilities in the plant can be achieved, providing energy management users with informational services for prior prediction, real-time analysis, and post-event tracking. 　　Unleash the potential for water conservation. Strictly control the temperature difference of the circulating water in terms of process requirements, and make timely adjustments according to seasonal changes and equipment load variations in order to reduce the amount of water used for circulation ； Enhancing the management of circulating water quality and optimizing operational procedures has resulted in a 25-ton/hour reduction in the wastewater discharge from the circulating water system ； Based on the principle of graded water utilization, the wastewater biochemical treatment effluent is used to replace fresh water, reducing the consumption of fresh water by 10 tons per hour. By implementing water-saving measures, the water consumption of polyolefins was reduced by 0.81 tons per ton, resulting in annual savings of 4.42 million yuan in water costs. 　　New models driven by intelligence As the first pilot enterprise for intelligent manufacturing in the coal chemical industry, this company relies on digital technologies in its production and operational processes; through digital transformation and the use of intelligent solutions, it manages to improve production efficiency and reduce consumption. 　　Sun Zongli explained that they have innovatively implemented an intelligent optimization project for steam, circulating water, and the carbon-hydrogen ratio in methanol synthesis across the entire plant, as well as optimizations and upgrades to the operating processes of units such as DMTO and gasifiers, thereby improving production efficiency through automation and intelligence. For example, through the intelligent optimization of DMTO units, the consumption of methanol as well as that of catalysts continues to decline ； Intelligent optimization of the gasification furnace reduces syngas consumption; it is estimated that each furnace can save 6,256 tons of raw coal per year, which is equivalent to a reduction of approximately 14,000 tons of carbon dioxide emissions ； Advanced control technologies are employed to continuously optimize the reaction conditions, reactor discharge, and recovery systems, thereby reducing the consumption of polyethylene. 　　To further improve energy utilization efficiency, reduce energy consumption and carbon emissions, the company will continue to implement measures to save energy and cut carbon emissions, strengthen energy-saving management throughout the entire process, actively promote a cleaner and lower-carbon energy structure, accelerate the development of new energy sources, and explore ways to utilize carbon dioxide as a resource, so that the energy consumption of its products exceeds the benchmark levels set for high-energy-consuming industries.