On-site source-separation of microparticles and reuse of coal gasification wastewater via a micro-channel separator: Performance and separation mechanism

The presence of microparticles in coal gasification wastewater (CGW) tends to cause fouling and blockage of heat exchangers and pipelines, increasing maintenance costs and affecting the stable operation of zero liquid discharge. Here, a 1 m(3)/h pilot-scale micro-channel separation technology was established for removing microparticles. The feasibility of this technology was verified by conducting a month-long field test. The results showed that the removal rate of suspended solids (SS) and the turbidity of the CGW were 85.2 % and 83.6 %, respectively. Over the operational period, the process was found to run stably, with an effluent turbidity < 20 NTU, which meets the requirements of subsequent working conditions. Scanning electron microscopy and X-ray diffraction techniques were used to characterize the separation medium, and no scaling was found on the surface during operation. In the micro-channel separation process, the removal of fine particles can be achieved without the addition of chemicals, thereby improving the operational stability of the existing process plant. The new method represents an environmentally friendly and sustainable process for the effective removal of SS from CGW.