Ceramic UF Membrane Retrofit: Rapid Results in Quality, Performance & Savings

Ceramic UF Membrane Retrofit: Rapid Results in Quality, Performance & Savings

Zhejiang Hengyang Thermal Power Company, located in China’s Zhejiang province, operates a coal-fired central steam and power plant producing 60 MW of power and 200 tons/hr of steam.
Located along the Haiyangtang River, the plant uses the river water — first treated with a clarifier and a sand filtration step— as a source for both cooling and boiler feed makeup water. The clarification system typically functions well, but during high turbidity excursions, the downstream
MMF/UF and RO systems both experienced significant problems.

Nanostone Water (Nanostone) determined that both the MMF and polymeric UF system could be replaced with its CM-151 technology, streamlining operations for the customer. Due to a high flux rating for CM-151 in this application (260 LMH), Nanostone determined that only 50% of the 112 polymeric UF modules would be required across four treatment trains to meet current and peak capacity. With minor mechanical modifications, the piping connections were retrofitted to accommodate the ceramic UF membranes, then connected to the existing common pipe and valve set for each membrane train. All of the remaining parts of the existing polymeric UF system were reused including the feed pumps, feed strainers, backwash pumps and chemically enhanced backwash (CEB) system.

Implementing CM-151 into the treatment process also reduced the need for the polymer program as the ceramic membrane system was able to create SDI < 2 consistently and reliably. In addition to significant chemical cost savings, an increase in recovery rates for the RO pre-treatment solution helped reduce backwash water generation by 50%. Furthermore, a reduced CEB frequency of 50% helped reduce additional operating expenses for the plant.

Nanostone’s CM-151 technology is operating with consistent pressure and dependably delivering high-quality water to the RO system with SDI values < 2 (typically < 1) and turbidity readings < 0.1 NTU. Delivering this water quality is critical to ensuring reliable operation in the downstream RO system — requiring less maintenance and cleaning events.

The Zhejiang Hengyang Thermal Power Company has been able to achieve lower operating costs with the more reliable and robust Nanostone CM-151 ceramic UF membranes in place. The additional benefits of guaranteed longer membrane life, higher recovery rates, lower CEB chemical usage, and reduction of a polymer chemical addition all contribute to a significant operating cost
reduction, as well as consistent and reliable operations for the thermal power plant.