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Spray water cooling for the exhaust gas purification project of Tower C2207 at Sino-Singapore Chemical’s methanol plant / Author/Source: Sino-Singapore Chemical / Date: 2021-07-14 / Clicks: 35. The exhaust gas purification project for Tower C2207 in Sino-Energy Chemical’s low-temperature methanol washing process is a key initiative for VOC control; it involves removing and replacing the trays from levels 2 to 16 of Tower C2207 with structured packing, increasing the amount of spray water used, and adding a desalinated water distributor as well as a wire mesh demister at the top of the tower. As a result, the methanol content in the exhaust gas exiting Tower C2207 is reduced to less than 50 ppm (W), thereby meeting the specified VOC emission standards. Since the temperature of the demineralized water supplied to our company is around 50°C during the summer, this affects the efficiency of absorption by the spray water. On the other hand, the temperature of the wastewater at the bottom of tower C2207 is only around 9°C; discharging this wastewater directly results in significant loss of cold energy. To recover this cold energy, it was decided, after consultation, to install a plate heat exchanger with a heat exchange area of 50㎡ on the pipeline carrying the demineralized water to the tower. This heat exchanger will exchange heat with the wastewater coming from the bottom of the tower, thereby recovering the cold energy from that wastewater and reducing the temperature of the demineralized water entering the tower. This approach not only improves the absorption efficiency but also reduces the amount of spray water needed, thus minimizing losses of demineralized water.