Abstract:
In order to develop a low emission municipal solid waste (MSW) fluidized-bed gasification and swirl-flow melting process, a fluidized bed gasifier was designed at the laboratory scale to research the gasification characteristics of PVC, which is widely existed in MSW and brings severe pollution and corrosion in MSW thermal disposal, especially the corrosion by HCl. The experiments were carried out at different excessive air ratios (0.2~0.8) and temperatures (400 ℃~700 ℃). The products from PVC gasification were characterized by using the proximate and ultimate analyzer, gas chromatography analyzer and titration of AgNO3. When the temperature is over 600 ℃ and the excessive air ratio is about 0.4, the conversion of Cl to HCl achieves over 95%. While the gasification efficiency reaches 22%~25% and the LHV of product gas is only 2 000 kJ/m3~2 300 kJ/m3. Increasing the temperature or excessive air ratio is an effective way to reduce the yield of smoke. When the temperature is 700 ℃ and the excess air ratio is 0.6, the yield of smoke is decreased to about 10%. Based on the results of experiments, the forming mechanisms of HCl and smoke are proposed and explained.