Combustion Characteristics and Pollutants in the Flue Gas During Shoe Manufacturing Waste Combustion in a 2.5 MWth Pilot-Scale Circulating Fluidized Bed

Abstract

Shoe manufacturing waste (SMW) was combusted in a 2.5 MWth pilot-scale circulating fluidized bed combustor (CFBC) to demonstrate the feasibility of energy recovery and provide useful information for a fluidized bed combustor design specifically for this waste. The experimental results confirmed that the stable combustion could be achieved in this CFBC with a constant feed flow rate of 400 kg/h, a primary air flow rate of about 1650 Nm3/h and a second air flow rate of about 1800 Nm3/h. The pollutants in the flue gas (ITFG) were measured with the average values of CO2 at 9.9%, CO at 2145.04 ppm, NOx at 81.67 ppm, SO2 at 32.62 ppm, HCl at 3.12 ppm, HF at 0.57 ppm, Pb at 0.0029 mg/m3, Cd < 0.001 mg/m3, Hg at 20.938 ng/Nm3, and PCDD/ PCDF at 1.17E−03 ng TEQ/m3, respectively. CO and SO2 emissions exceeded the legal limits in China, while the combustion efficiency was relatively low. Therefore, in order to meet the CO emission limit, some useful suggestions were put forward for the future CFBC design to burn SMW. A flue gas desulfurization system is essential to reduce the SO2 emission. Very low Cu content, high level of residual carbon in the fly ash and high SO2 concentration ITFG resulted in low PCDD/PCDF emission.