Integrated process control for recirculating cooling water treatment in the coal chemical industry

摘要

This work focused on the integrated process of the recirculating cooling water (RCW) treatment tonachieve approximate zero emission in the coal chemical industry. The benefits of fractional andncomprehensive RCW treatment were quantified and qualified by using a water and mass balancenapproach. Limits of cycle of concentrations and some encountered bottlenecks were used tonascertain set target limits for different water sources. Makeup water was mixed with water producednfrom reverse osmosis (RO) in the proportion of 6:4, which notably reduced salts discharge. Sideninfiltration, which settled down suspended solids, can reduce energy consumption by over 40%. Annautomated on-line monitoring organic phosphorus inhibitor feed maintains the RCW system stabilitynin comparison to the manual feed. Two-step electrosorb technology (EST) instead of an acid feed cannlead cycle of concentration of water to reach 7.0. The wastewater from RO, EST and filter wasntransferred into a concentration treatment system where metallic ions were adsorbed by permanentnmagnetic materials. Separation of water and salts was completed by using a magnetic discnseparator. Applying the integrated process in a coal chemical industry, a benefit of 1.60 million Yuannannually in 2 years was gained and approximate zero emission was achieved. Moreover, bothntechnical and economic feasibility were demonstrated in detail.