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Changqing Energy Chemical Company: Making the Most of Waste Utilization Author/Source: Sinochem News Network Date: March 24, 2023 Clicks: 18 —— Part Three of the Series on Typical Cases of Energy Conservation and Emission Reduction in Shaanxi’s Chemical Enterprises As a large-scale coal chemical enterprise, Shaanxi Changqing Energy Chemical Co., Ltd. (hereinafter referred to as Changqing Energy Chemical Company) has been operating its 600,000-ton per year coal-to-methanol production facility for 10 years this year. While ensuring stable and high production levels in its manufacturing facilities, the company adheres to the principles of energy conservation, carbon reduction, and cost reduction. It carries out technical upgrades aimed at making comprehensive use of industrial waste such as fly ash and exhaust gases, striving to maximize the utilization of these resources through reduction, recycling, and substitution. This approach helps achieve energy savings and emission reductions, transforms waste into valuable resources, and lowers costs while increasing efficiency, resulting in significant environmental and economic benefits. As a result, the company has earned a reputation as being green and energy-efficient. Boilers using mixed fuels save energy and improve efficiency. The power generation units of Changqing Energy & Chemical Company are equipped with 3 coal-fired boilers, and reducing the consumption of coal as fuel for these boilers has become one of the key focuses of innovative research aimed at saving energy and reducing carbon emissions. In 2021, after thorough research, the company assigned relevant technical staff to carry out the “Project for Energy-Saving Upgrades through Mixed Combustion of Resources in Boilers”. A technical team composed of heads from departments such as the Production and Operation Department and the Technical Development Department is working on technological solutions related to the use of industrial waste in boiler operations; this team focuses on recycling gases generated during production, industrial exhaust gases, contaminated methanol, and fusel oils, and using them as fuel in boilers. When starting a boiler, diesel is commonly used as fuel in the industry; it results in high energy consumption, produces heavy black smoke that causes pollution, and also affects the proper operation of subsequent facilities such as dust removal and desulfurization systems. “The methanol produced by the company is a superior clean energy source; we wondered whether it could be used to replace diesel for ignition. That’s what we thought at the time. ”Wang Cheng, one of the main participants in this project and head of the Technology Development Department at Changqing Energy Chemical Company, told reporters that through analysis, optimization, and appropriate modifications to the boiler ignition system, using methanol instead of diesel for ignition proved to be very effective. Similarly, fusel oil and contaminated methanol produced as by-products in methanol production are also organic liquid mixtures containing methanol, higher alcohols, and alkanes; they are classified as hazardous waste and require costly disposal. After implementing measures to reduce fusel oil and upgrading the distillation system, the daily output of fusel oil dropped from 24 tons to around 2 tons. The reduced amount of fusel oil was sent to the methanol ignition system in front of the boiler as fuel; this not only allowed for the utilization of its thermal value but also reduced the processing costs. Having experienced the benefits of energy-saving upgrades, the technical staff at Changqing Energy Chemical Company continued to brainstorm, focusing their attention on solid waste and industrial exhaust gases. Like similar domestic enterprises, the fine slag produced by gasification units is considered industrial solid waste, containing a certain amount of carbon. To utilize the thermal energy contained in it, they simply process the vaporized fine slag and mix it with fuel coal in a certain proportion before feeding it into a pulverized coal boiler for combustion. This approach reduces the consumption of fuel coal while keeping the boiler load constant, and it also lowers storage costs and environmental pollution. Currently, the proportion of gasified fine slag used in combustion is around 10%, with nearly 100 tons being used per day. Industrial exhaust gases such as those from methanol production synthesis venting contain combustible gases like carbon monoxide and hydrogen; these small amounts of gas used to be sent to the fuel gas main line and burned off through flares. Changqing Nenghua Company has carried out technical upgrades; after extracting hydrogen through membrane recovery, the remaining gas still possesses a certain calorific value. Part of this gas is sent to boilers as fuel to replace liquefied petroleum gas in heating processes, while another part is injected into the boiler furnace to burn and release heat, thereby minimizing energy waste and reducing emissions. In 2022, the boiler co-combustion and resource-based energy-saving technology project of Changqing Energy Chemical Company, with a total investment of 1.5 million yuan, was put into full operation. “According to calculations, after the project is implemented, approximately 15,000 tons of thermal coal can be saved each year, which not only reduces environmental pollution but also generates direct economic benefits of nearly 6 million yuan. ”Wang Cheng said that the project won the first prize for scientific and technological achievements of the company in 2022, and his team received a reward of 30,000 yuan as a result. All employees work together through innovation to tackle complex challenges. According to interviews with reporters, the reason why Changqing Energy Chemical Company has been able to make optimal use of \"three types of waste\" is its emphasis on innovation among all employees, as well as its continuous investment in research and development. By carrying out technical upgrades to its production systems, the company has managed to overcome the various challenges that affect the safe operation of its facilities, thus paving a new path for coordinated development of ecology and the economy through technological innovation. “Last year, our expenditure on technology research and development accounted for over 3% of our total output value, and this year the investment in research will reach 48 million yuan. ”Wang Tuqin, general manager of Changqing Nenghua Company, told reporters that as a **high-tech enterprise, the company has introduced the \"Management Measures for Scientific and Technological Progress\" to encourage its employees to develop applied scientific and technological achievements by taking on research projects. These evaluations are conducted once a year, and rewards are given based on the level of technology, the benefits achieved, and the extent of contribution, thereby stimulating the enthusiasm of professional technicians and employees for innovation in science and technology. In terms of energy conservation and emission reduction, a series of projects aimed at reducing coal consumption and improving efficiency were implemented. More than 120 energy-saving technologies, such as increasing the concentration of water-coal slurry, pre-concentration of shift condensate through double-tower stripping for ammonia recovery, and recovery of exhaust gases from the methanol synthesis process, have been granted patents. These efforts resulted in annual savings of 1.02 million kWh of electricity, 25,000 tons of standard coal, and 57,000 tons of water, generating comprehensive economic benefits of nearly 40 million yuan. Pollutant control helps create a clean environment. At the Changqing Energy Chemical Company, the reporter observed that there was very little smoke emitted from the boiler chimneys and little steam from the production equipment, and no unusual odors were detected. In the central control room, the journalists were attracted by the desulfurization outlet emission figures displayed in real time on the computers. “We have installed two sets of ammonia-based desulfurization and bag filter dust removal systems. Through real-time technical upgrades to the oil vapor recovery system at the methanol loading platform, we have eliminated the hazards posed to personnel and the environment by the uncontrolled emission of volatile organic compounds during methanol loading. We make use of all the waste heat and pressure that can be recovered; for example, the steam generated as a by-product of temperature and pressure reduction is used for power generation, producing 240 million kWh of electricity per year. This enables self-sufficient power supply to meet the production needs. Meanwhile, improvements are being carried out on the vent gases from the methanol storage area, with the aim of recovering gases such as carbon monoxide and hydrogen sulfide. ”Wang Cheng revealed the secret to the reporters. It is said that Changqing Energy Chemicals does not overlook the active components in the wastewater generated during production. The ammonia-containing wastewater is purified and concentrated, after which ammonia is recovered through local circulation for reuse; this results in an additional 1,730 tons of liquid ammonia per year, all of which is used for desulfurization. The pollutants in the process wastewater and rainwater are at extremely low levels, meeting the standards for class III water quality, allowing them to be reused in the gasification sedimentation tanks or for landscaping, thereby significantly reducing the amount of wastewater discharged outside. In recent years, Changqing Energy & Chemical Company has invested 400 million yuan in the construction and upgrading of environmental protection facilities, making every effort to manage pollutants such as industrial waste gas, wastewater, solid waste, and noise. By implementing environmental protection measures such as upgrades to boiler dust treatment systems, wet electrostatic precipitators, backup desulfurization systems, flue gas whitening technologies, enclosed coal storage areas, and controls for volatile organic compounds, they not only keep the pollutant levels in their atmospheric emissions well below the **standard limits by more than 70%, but also reduce carbon dioxide emissions by 150,000 tons per year.