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Successful technical upgrade of the wastewater discharge system for the ammonia removal condensers in Zhejiang Energy Xintian Coal Chemical Industry Author/Source: Zhejiang Energy Xintian Coal Chemical Industry Date: May 22, 2020 Clicks: 3 On May 16, the technical upgrade of the wastewater discharge systems for the ammonia removal condensers in Series A and B of Xintian Coal Chemical Industry’s phenol recovery unit was completed successfully. The successful commissioning of the new waste discharge collection tank has enabled closed-system collection of waste discharges, further addressing the challenges associated with the treatment of hazardous waste at Xintian Coal Chemical Industry. During the production process, it not only eliminates potential safety hazards but also reduces operating costs, providing a solid guarantee for the safe and stable operation of the phenol recovery unit. The phenol recovery unit in the recycling workshop of Xintian Coal Chemical uses the extraction principle to separate phenol from coal gas water, and sends the qualified dilute phenol solution to subsequent processing stages for further treatment. The raw coal gas and water are subjected to processes of acid and ammonia removal, as well as temperature and pressure increase; after that, they are cooled in an ammonia removal water condenser, during which some soluble oils are separated out. These oils affect the cooling efficiency of the condenser. If the oil contamination is not removed promptly, it will end up in the system, affecting subsequent distillation processes, leading to a decline in the quality of the solvents and resulting in substandard quality of the by-product mixed phenol. Therefore, the asphalt must be discharged directly into the designated containment area. However, continuous discharge of such oil contamination not only causes environmental pollution but also poses safety risks. Due to the high viscosity of the asphalt discharged from the ammonia removal water condenser in the phenol recovery unit, it cannot be transported directly to the coal yard for mixing with pulverized coal; it has to be stored on-site at the phenol recovery location. There is no effective way to deal with it, and it emits a strong odor, making it a persistent problem for the recovery workshop of New Tian Coal Chemical Industry. To address this issue, the management of Xintian Coal Chemical’s recovery workshop held several meetings to decide that sealed waste collection tanks should be added to the drainage system of the ammonia removal water condenser. The oil contaminated with asphalt would then be sent to the gas-water separation unit for further separation, thereby preventing environmental pollution, avoiding solvent loss, and increasing the output of by-products. After nearly a month of intensive testing and debugging, series A and B of the phenol recovery units in the recycling workshop have now completed this technical upgrade. Following the modification, the asphalt wastewater tanks perform well, operating in a safe, stable, and reliable manner. Through the modification of the asphalt waste tank, it is possible to ensure that the asphalt discharged from the ammonia removal water cooler flows at high temperature and mixes with the ammonia removal water before entering the asphalt waste tank; this results in good fluidity, after which the asphalt is transported to the gas and water system via an asphalt pump. During operation, a slight odor of asphalt will emanate. It solved the problem of difficulty in recycling asphalt after it falls to the ground, achieved sealed collection of waste emissions, and met the expected results ； In addition, the on-site technical upgrades have also reduced operating costs and improved economic efficiency; based on current market prices for by-products and estimates for dredging costs, it is expected that operating costs can be saved by approximately 672,000 yuan per year. At present, the construction of the Phenol Recovery C series is in full swing. This year, Xintian Coal Chemical aims to produce 1.9 billion cubic meters of natural gas. As the overall production load increases, the oil and dust content in the gasification wastewater rises, leading to an accumulation of oil and dust within the system and posing an increasingly serious threat to the production process. This technical modification, through the phenol recovery unit in the recycling workshop, addresses issues such as difficulties in waste disposal, high risks associated with waste discharge, high levels of waste generation, and challenges in asphalt treatment. It further lays a solid foundation for energy conservation and emission reduction, effectively solving the problems related to the handling of solid waste in enterprises.