Experimental investigation of oxy-combustion using plastic waste pyrolysis fuel for CO2 capture technology

초록

In response to the worsening environmental and energy crises, strategic research on plastic disposal (pyrolysis) and CO2 negative application (oxy-fuel combustion) was carried out. The upgraded plastic pyrolysis oil was used to evaluate the performance of oxy-fuel combustion in a 5-kW scale boiler. Plastic oil middle distillate (diesel-like fraction, C-11-C-22) exhibits similar characteristics to diesel (e.g. HHV: 45.0 MJ/kg, viscosity: 2.70 cSt at 40 degrees C), resulting in a perfect miscibility. The 30 %P-oil (mixed fuel of plastic middle fraction pyrolysis oil for 30 wt% and petroleum diesel for 70 wt%) and pure diesel were applied for the oxy-fuel combustion study, respectively. The boiler efficiency of 30 %P-oil was about 62 %, close to pure diesel combustion (similar to 61 %), higher than air combustion (similar to 58 %) with mixed fuels in our previous study. The maximum boiler internal temperature was observed at 1080-1090 degrees C at 25 %O-2 and 75 %CO2 of inlet gas concentration. Emission analysis showed that both the 30 %P-oil and diesel combustion emitted similar flue gas concentrations of CO (80-120 ppm), SO2 (6-9 ppm) and CO2 (similar to 95 %) at 25 %O-2 condition. On the other hand, 30 %P-oil showed higher NO concentration (61 ppm) than diesel (20 ppm) because of higher presence of the nitrogen content in plastic pyrolysis oil. Finally, highly concentrated CO2 (similar to 95 %) was captured over oxy-fuel combustion, leading to CO2-negative technology.

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