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Polychlorinated diphenyl ethers (PCDEs), persistent environmental pollutants, are found in flue gas from incinerators. While air pollution control systems (APCSs) capture pollutants, the resulting sludge/fly ash (SFA) requires further treatment due to residual PCDEs and other harmful substances. This study investigated a hazardous waste thermal treatment system (HAWTTS) utilizing flameless combustion technology alongside a multistage APCS (scrubbers, cyclone demisters, bag houses). SFA from the APCS was recirculated for secondary combustion. PCDE levels were measured before and after each unit within the HAWTTS. The HAWTTS achieved a remarkable overall PCDE removal efficiency of 99%. However, the incinerator alone was less effective for low-chlorine PCDEs. Scrubbers and bag houses exhibited lower removal efficiencies (17.8% and 30.9%, respectively) due to the memory effect. Conversely, the cyclone demister achieved a high removal rate (98.2%). Following complete APCS treatment, PCDE emissions were significantly reduced to 1.02 ng/Nm3. While SFA still contained some PCDEs, the flameless combustion's uniform temperature distribution enhanced combustion efficiency, minimizing overall PCDE emissions. This system demonstrates significant potential for mitigating PCDE pollution from incinerators. Further research could focus on optimizing treatment processes to address residual PCDEs in SFA. [ABSTRACT FROM AUTHOR]

To investigate the heat pump performances at the condition of four-way reversing valve leakage, a test-rig was built by which tests were conducted, and experimental data such as pressure anti temperature of compressor suction and discharge, air temperature difference through the indoor coil, and compressor power consumed were measured. The experimental results show that the leakage makes the pressures of compressor suction and discharge declined, the temperatures of compressor suction and discharged increased, the air temperature difference of indoor coil lowered to 0.9 °C ,and the compressor input power to be only 58.6% of that without leakage, which means the performance of heat pump has been seriously affected by the leakage of four-way reversing valve. The results are helpful to the fault detection of four-way reversing valve and the performance diagnosis of heat pumps. [ABSTRACT FROM AUTHOR]