| dc.description.abstract | This research investigates that automobile shredder residue (ASR) converted into energy by fluidized bed gasification system with controlling at ER 0.3, temperature 850℃ and 0~50% ratio calcined dolomite addition as the catalyst and bed material replacement. The producer gas composition, product distribution, energy yield efficiency and trace pollutants (e.g. heavy metal, sulfur, and chlorine) emission characteristics were evaluated.
In the case of without calcined dolomite replacement test, the H2 and CO composition were 3.57 vol.% and 4.86 vol.%, respectively. When the bed material was replaced by 30% calcined dolomite, the H2 and CO composition was slightly increased to 3.99 vol.% and 5.95 vol.%, respectively. The syngas production increasing rate was approximately 10.5% and 18.3%, respectively. The energy yield efficiency of ASR catalyst gasification was increased with an increase in calcined dolomite replacement ratio, especially for 30% replacement ratio. The heating value of producer gas increased from 3.50 MJ/Nm3 to 3.85 MJ/Nm3 with calcined dolomite replacement ratio increasing from 0% to 30%. The gas energy density was also increased from 4.98 MJ/kg to 5.14 MJ/kg as well as the cold gas efficiency (CGE) was increased from 17.40% to 17.95%. Based on the results of energy conversion efficiency, replacing quartz sand with calcined dolomite could enhance the energy yield efficiency in ASR gasification.
The heavy metals emission characteristics results indicated that Cu, Zn, Cr, and Pb were mainly partitioned in the solid phase as calcined dolomite used in quartz sand replacement. That is, when calcined dolomite was used in gasifier, the above metals were significantly decreased in syngas as well as the metals emission was aslo reduced. In the case of without tested calcined dolomite replacement, the Cu, Zn, Cr, and Pb partitioning percentages in the gas phase were 11.71%, 9.07%, 8.11%, and 36.28%, respectively. In the case of 30% calcined dolomite replacement ratio, the above metals partitioning percentages in the gas phase were decreasing to 0.03%, 0.91%, 0.58%, and 1.13%, respectively. However, Cd and Hg were mainly partitioned in the syngas resulting in their high volatility characteristics. Obviously, the calcined dolomite addition was insignificant effect on Cd and Hg partitioning characteristics.
According to the results of the sulfur and hydrogen sulfide emission characteristics, in the case of without tested calcined dolomite replacement ratio, the sulfur partitioned in the gas phase and liquid phase were 57.6% and 8.06%, respectively. When replacing bed material with 30% calcined dolomite, the above sulfur partitioning characteristics were decreased to 16.6% and 2.08%, respectively. The concentration of hydrogen sulfide in syngas was decreased from 570.84 ppm to 439.38 ppm with an increased in calcined dolomite replacement ration from 0% to 30%. The hydrogen sulfide removal rate was approximately 23%. Meanwhile, in the case of without tested calcined dolomite replacement ratio, the chlorine was almost 60.84% partitioned in the gas phase. when replacing bed material with 30% calcined dolomite, the chlorine partitioning percentage in the gas phase was also significantly decreased to 20.91%. Overall, replacing quartz sand with calcined dolomite is beneficial to reduce the chlorine and sulfide emission in the syngas.
In summary, this research has proved the calcined dolomite could replace quartz sand as the bed material. It could enhance energy conversion from ASR via catalytic gasification, but also reduce the derived pollutants (e.g. heavy metal, sulfur, and chlorine) emission during the ASR gasification process. Therefore, the results of this research could provide useful information for the selection of catalytic gasification technologies and control strategies of pollutants emission in the future. | en_US |