| The production of gasification fine slag is increasing with the promotion of coal gasification technology,and its resource utilization rate is low compared with other solid wastes,while gasification slag blending can realize the industrialization environmentalization and economization of gasification slag utilization.In this paper,based on the high residual carbon content and unique particle size characteristics of gasification fine slag,typical Tecxaco gasifier fine slag YL and Shell gasifier fine slag AQ were selected to obtain gasification fine slag of various particle sizes(YL1?L6,AQ1-AQ6)by physical screening.The physicochemical properties and residual carbon structure of each particle size gasification fine slag were analyzed by mass distribution(PID),residual carbon(LOI),scanning electron microscopy(SEM),X-ray diffractometer(XRD),Fourier infrared spectroscopy(FT-IR)and Raman spectroscopy(Raman).The combustion characteristics of each type of particle size slag were investigated by TGA,and the combustion characteristics of the residual carbon were explored by acid leaching and crushing methods to eliminate the effects of particle size and inorganic components.The mixed combustion characteristics of two specific particle size fines(YL4,AQ5)and fuel coal SY were investigated by TGA,and the mixed combustion characteristics and interaction between YL4,AQ5 and SY were examined by using the interaction index xd of mixed combustion and Coats-Redfern integral equation analysis.The main findings are as follows.The particle size distribution of gasification fine slag has multi-peak agglomeration.Due to the variability of the gasification process,the overall particle size of YL is smaller,the mass distribution of each particle size is more different,and the burn loss is lower compared to AQ.The residual carbon of the gasification fine slag is mostly distributed in the large particle size slag samples,and the particle formation of the apparent morphology of each particle size slag is attributed to the different gasification history it undergoes in the gasifier.As the particle size of the slag sample decreases,the residual carbon voids corresponding to the acid washing are more developed,and there are still functional groups such as aliphatic long chains,aromatic carbon rings C=C and small amounts of SiO2 in the raw coal.Therefore,the overall order of the smallsize residue is slightly lower than that of the large-size residue.The small size residue particles are less affected by the reaction resistance during combustion and can burn quickly and completely.With the increase of particle size,the combustion interval of slag particles was delayed in turn,but the overall combustion index S showed an increasing trend.After acid leaching,the inorganic ash in the slag particles was removed in large quantities,and as the particle size increased,the corresponding residual carbon TG-DTG curve shifted to the high temperature zone in turn,the flocculent carbon gradually decreased,and the lumpy particle carbon was more regular.The ignition point of each proportional blend sample was advanced relative to YL4 and AQ5 simple combustion and the combustion interval became shorter.As the proportion of YL4 and AQ5 increased,the corresponding weight loss curves showed a hysteresis phenomenon,and the weight loss became smaller,and the comprehensive combustion index S decreased.The interaction index xd is mainly influenced by the combustion temperature interval and mixing ratio.When the proportion of YL4 blending reaches 30%and the proportion of AQ5 blending reaches 50%,the synergistic interaction effect of mixed combustion is the most obvious,and its Em is reduced to the lowest respectively.Figure[33]Table[19]Reference[115]... |
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