Study On Chemical Loop Pyrolysis Gasification Reaction Kinetics & Reaction Activity Of Mixed Low Rank Solid Fuel

How to handle large production of coal mine rejetcs and industrial sludge is one of the most serious environmental problems.However,coal mine rejetcs and industrial sludge are available potential energy resources.But the large-scale energy of these solid wastes is severely restricted,due to their high ash,low heat value and difficult to combustion.In order to achieve the high efficiency and clean in gasification and combustion of the low rank solid fuels such as coal mine rejetcs,industrial sludge,oxygen carrier and biomass are added during the gasification and combustion processes.The achievement to obtain the high rank of alternative fuels and chemical products is a hotspot of domestic and international research.Nowadays,there is a lot of research on the technology,equipment,mechanism and characteristics of pyrolysis gasification for biomass,coal mine rejetcs or industrial sludge.However,the high efficient pyrolysis gasification mechanism and feature of the mixtures remain at the conventional method which need is required to make a major breakthrough.Moreover,it is still difficult to obtain high gasification efficiency and improve the gasification gas grade by using the conventional heating method.Accordingly,this paper applies the chemical loop pyrolysis gasification reaction principle to the pyrolysis gasification by experiment and theory method.The main research focuses on the similarities and differences of in the chemical loop pyrolysis gasification reaction kinetics model,reaction activity and the characteristics under the condition of biomass,coal mine rejetcs,industrial sludge and their mixtures.This paper is beneficial to develop a new low rank solid fuel chemical loop pyrolysis gasification process and realize to achieve the efficient clean utilization of the low rank solid fuel.This paper systematically analyzed the chemical loop pyrolysis gasification kinetics models,reaction activity and features of typical biomass walnut shell,paper making,beer sludge and Chinesemedicinepharmaceutical industry and coal mine rejetcs atvarious regionsby using TGA,tubular reactor and FTIR.The thorough analysis on the chemical loop pyrolysis gasification models,reaction activity and characteristics of typical biomass,industrial sludge,and coal mine rejetcs were also carried out under different ratios of oxygen carrier(Ni O,Cu O and Fe2O3).The dynamic characteristics and models,reaction activity were also discussed under different ratios of biomass,industrial sludge and coal mine rejetcs.Moreover,different oxygen carrierswere also taken into consideration.The reactivities activities of biomass,industrial sludge,coal mine rejetcs and the mixtures under the action function of oxygen carrier in different temperature areas,the optimum combination of oxygen carrier and the ratio of the mixtures under at high reactivities activity were analyzed.Besides,the evaluation method of the reactivity was also included.The innovative results are shown as follows:It is found that the addition of the metaloxygen carrier could promote the pyrolysis gasification reaction of the low rank solid fuel and its mixtures.However,different kinds of oxygen carrier show the difference in the pyrolysis gasification reactivity of different kinds of low rank solid fuel.For coal mine rejetcs,Ni O is easy to have chemical chain reaction with coal mine rejetcs at low temperature(437? to 591?).Cu O is easy to have chemical chain reaction with coal mine rejetcs at medium moderate temperature(591? to 900?),while Fe2O3 need overcome a low activation barrier to react with coal mine rejetcs at high temperature(900? to 1163?).For industrial sludge,the TG/DTG peak greatly changed due to the addition of oxygen carrier.The weightlessness peak increased and the maximum temperature when weightlessness peak appeared reduced about 15? which resulted in a contribution to the pyrolysis gasification reaction.The higher heating rate was,the higher weightlessness rate was.The amount of gas productions increases based on the above following trend.The activity order for oxygen carrier to prompt the chemical loop pyrolysis gasification is Ni O>Cu O> Fe2O3.The industrial sludge kept higher pyrolysis gasification reactivity with Ni O at low,moderate and high temperature.For biomass,the walnut shell kept high pyrolysis gasification reactivity with Ni O at the low temperature zone(< 700?).The reactivity of Fe2O3 is better at high temperature(> 700?).For the mixtures of biomass/coal mine rejetcs/industrial sludge,the reactivity and acceleration differ at various temperature zones in chemical loop pyrolysis gasification reaction.Ni O is more likely to promote the mixture pyrolysis gasification in a relatively low temperature zone(below 450?).Cu O is more likely to promote the pyrolysis gasification of the mixtures at the moderate temperature area(about 450~650 ?).Fe2O3 exhibits an obvious promoting effect on pyrolysis gasification reaction of the mixtures.It is found that the kinetic characteristics of chemical loop pyrolysis gasification reaction vary a lot for different low rank solid fuel with various oxygen carriers.The chemical chain reaction series between the carrying oxygen of Fe2O3,Cu O,Ni O and coal mine rejetcs is 1,while at low temperature(< 900?)and high temperature(>900?)area without the oxygen carrier are 1 and 2.5 respectively.The reactions are divided into low,moderate and high temperature zone for these three kinds of oxygen carrier which reacts with biomass,industrial sludge and the mixture of biomass/coal mine rejetcs/industrial sludge.However,the pyrolysis gasification reaction series is different.For industrial sludge,the pyrolysis kinetics reaction progression of low,moderate and high temperature zone is 1.5,2 and 1 respectively.For biomass,the kinetics reaction progression of the three kinds of carrying oxygen is 1 in low temperature zone.When the reactions are conducted at moderate temperature zone,the kinetics reaction orders of Fe2O3,Ni O and Cu O are 2,3,2 respectively.The kinetics reaction orders of the three kinds of oxygen carrier are 1 at high temperature zone.Every temperature pyrolysis kinetics model for the mixture of biomass/coal mine rejetcs/industrial sludge is reaction orders model or phase interface model.For low-temperature zone,the dynamic model is 1 level reaction kinetics model or R2 phase interface model.For moderate temperature zone,the pyrolysis kinetics model is 3 levels reaction kinetics model.For high temperature zone,the pyrolysis kinetics model is 2,2.5 or 3 levels reaction kinetics model.It is found that there always exists proper ratios of Cu O,Ni O and Fe2O3 which could reach keeps higher reactivity throughout the temperature zone of chemical loop pyrolysis gasification of the coal mine rejetcs,industrial sludge,biomass and their mixtures.For coal mine rejetcs,the mole ratio(nCu O: nNi O: nFe2O3)is 0.35:0.28:0.37.For industrial sludge,nNi O=1.For biomass,the mole ratio(nCu O: nNi O: nFe2O3)is 0.15:0.52:0.33.For the mixtures of biomass/coal mine rejetcs/industrial sludge,the mole ratio(nCu O: nNi O: nFe2O3)is 0.47:0.15:0.38.To study and put forward the low rank chemical chain of oxygen carrier of solid fuel mix/metal oxygen carriers in the pyrolysis gasification reaction reactivity can be made of metal oxygen carriers generated enthalpy factors ?(metal body product of oxygen carryier of the generation of the enthalpy and metal body the generation of the enthalpy difference and low rank solid fuel ratio of the high calorific value)to determine the size.When the enthalpy factor of the metal oxygen carrier?is close to 1,the activity of the low rank solid fuel/carrier chemical loop pyrolysis is the highest,and the further the ?deviation is,the lower the reaction activity is.In the biomass/coal mine rejetcs/typical industrial sludge mixed fuel chemical loop pyrolysis,the three kinds of oxygen species are maintained at(nCu O: nNi O: nFe2O3)0.47:0.15:0.38.The chemical loop pyrolysis gasification reaction activity was the largest in the whole temperature zone,and the enthalpy factor ?of the formation of the mixed metal oxygen carrier was close to 1.Studies have shown that improve the proportion of biomass,mixed straw is more advantageous to biomass/coal mine rejetcs/industrial sludge pyrolysis gasification solid mixture fuel chemical chain reaction,and found that mixing ratio on activation energy is larger,the mixing mass ratio,biomass: coal mine rejetcs:industrial sludge = 3:1:1,the overall activation energy is the minimum,which is advantageous to in favor of the pyrolysis gasification reaction.The activation energy of biomass/coal mine rejetcs/industrial sludge mixed fuel chemical chain reaction can increase with temperature and decrease in some area.The composition of biomass,coal mine rejetcs and industrial sludge is relatively varied different,but their chemical loop pyrolysis characteristics changing follow the same similar trend.The initial segment of pyrolysis reaction is the stage of water precipitation,which has low activation energy and frequency factor.As the temperature increases,both activation energy and frequency factor increase.But as the volatilization of the release becomes larger and larger,in the volatile analysis to reach the maximum weight loss rate,the activation energy decreases,then the activation energy and the frequency factor become larger.Biomass volatilization content is very high,ash content is a little,especially walnut shell,volatilize cent is nearly 80%,and ash is less than 1%;The common characteristics of industrial sludge are high in ash content and less than 1% in fixed carbon.Coal mine rejetcs contains more ash(over 50%)and very little volatilization.The process of pyrolysis of industrial sludge was not significantly altered due to the mixing of samples.The volatile analysis of the mixed sample was related to the mixing ratio.Biomass pyrolysis gasification process,when there is no oxygen carrier,pyrolysis for CO2,CO,H2,and the amount of CO2,H2 generation is not high,when supplied with oxygen carrier,increase in CO and H2 generation pyrolysis gas composition,illustrate the oxygen carrier to promote the generation of the amount of CO and H2.Three oxygen carriers under the condition of oxygen carrier of pyrolysis gas have some distinctions,Ni O walnut shell could produce more H2 in the pyrolysis process,Cu O walnut shell shows the lower H2 and CO selectivity compared with the other two,while Fe2O3,enhances the CO generation,furthermore,the yields of CO and H2 increase with the temperature rising.The content of the pyrolysis of the low rank solid mixed fuel/oxygen carrier chemical chain reaction is closely related to the temperature of different pyrolysis.The paper shows that the high temperature segment of the chemical loop pyrolysisgasification of three kinds of mixed fuels is are CO2 and CH4 and a small amount of CO.Activity of coal mine rejetcs and N2,CO2 and CH4,CH4 atmosphere more can promote the coal mine rejetcspyrolysis at low temperatures,CH4 atmosphere on coal mine rejetcspyrolysis had best temperature sections range in terms of promoting function of Topt,CH4 before analysis of carbon temperature,pyrolysis of coal mine rejetcs was to promote the role.The higher the concentration of methane is,the more obvious the effects are.At some temperatures,the existence of coal mine rejetcs also promotes methane cracking.The atmosphere of CH4 has the highest critical temperature and the carbonation temperature for the pyrolysis of coal mine rejetcs.All in all,chemical loop pyrolysis gasification kinetics model,characteristics reaction activityhave been systematic studied for biomass,coal mine rejetcs,industrial sludge,and their mixtures with Ni O,Cu O,Fe2O3 in this paper,the composition of mixed oxygen carrier chemical loop pyrolysis gasification kinetics characteristics and model,reaction activity found with high reactivity of low rank fuel and oxygen ratio of oxygen carrier composition,proposed the low rank fuel blends and the oxygen carrier chemical chain method of valuing the pyrolysis gasification reactivity.The results of this paper are beneficial to further development of novel low rank solid fuel chemical loop pyrolysis gasification process,realize achieve the efficient clean utilization of low rank solid fuel to lay the solid theoretical foundation.Moreover,the research is of great importance from academic significance and reference value in engineering.