Experimental Study On Essential Design Parameters Of Biomass And Coal Co-gasifier

As the world energy situation has become tighter,and the ecological environment for human beings to disaster is more and more serious,positive rational development and utilization of new pollution-free green energy is a top priority to solve the problem.Biomass as the only carbon-based green energy,have been attracting the attention of the whole world increasingly.Clean and efficient use of biomass energy,for the establishment of multi-energy system,and maintaining ecological balance,ensuring social and economic development sustainable has important practical significance.Biomass and coal co-gasification technology,not only reducing the consumption of fossil fuels,while the reasonable use of biomass energy,in line with the requirements of national sustainable development strategy.According to the Tianjin Municipal Government planning of Tianjin,a company plan to construct of the biomass and coal co-gasification device in cycle economic zone.By the way,the device has capable of processing cotton stalks in near cotton fields and pieces of wood waste generated by fungus farming.In order to provide basic design parameters support for coal gasification unit,the company commission Shenyang Institute of Engineering Key Laboratory of Biomass Utilization of Shenyang to analyze the interaction situations of cotton stalks/sawdust and coal co-gasification/co-pyrolysis.Based on research progress in domestic and abroad of biomass and coal co-gasification/co-pyrolysis,in this paper,we will study the interactions in process of co-pyrolysis of biomass(cotton stalks,sawdust)and lignite under different conditions(pyrolysis atmosphere,heating rate,mixed mode).Firstly,make biomass(cotton stalks,sawdust)and coal separate pyrolysis experiments,draw TG curve of each pyrolysis process in different atmosphere and heating rate.The results show that:during pyrolysis in N2 atmosphere,mainly pyrolysis temperature interval of biomass and coal are different,cotton stalks(250?350?),sawdust(280?400?),coal(400?500?);During pyrolysis under the gasification atmosphere,cotton stalks occur secondary gasification reaction after 800?,but sawdust and coal all have no secondary reaction;heating rate for biomass and coal pyrolysis process had no obvious effect.Secondly make biomass and coal co-pyrolysis TGA experiments,draw TG curve of each pyrolysis process in different atmosphere,heating rate and hybrid mode.Convert the experimental value on each temperature point in biomass and coal separate pyrolysis process by mixing ratio to theoretical value,get difference through the experimental value minus theoretical value,draw the difference curve,obtain the generation and changed of interaction in co-pyrolysis.The results show that:in N2 atmosphere,when at 60?/min and uniform mixing mode,the cotton stalks and coal co-pyrolysis process shows the strongest synergy performance,and reaches the peak at 350?;In sawdust and coal co-pyrolysis process,the inhibition achieves the minimum when heating rate at 20?/min and increase with the increase of heating rate,and shows strong inhibition in 360?.In sawdust and coal co-pyrolysis process at gasification atmosphere,shows weak synergy at about 360?,the process of interaction with the overall performance is not obvious;In cotton stalks and coal co-pyrolysis process,all shows strong synergy at 900 ?,and achieves the maximum at uniform mixing mode.Make analysis of reaction kinetics on experimental procedure above,get the value E of activation energy in pyrolysis process by Coats-Redfem method.The results show that:when separate pyrolysis,the value E of coal pyrolysis under various working conditions are higher than biomass,value E of sawdust pyrolysis process are slightly higher than the cotton stalks;The activation energy of biomass and coal co-pyrolysis shows an increasing trend with the increase of heating rate;Mixed mode has no significant effect on the activation energy of co-pyrolysis process,but the activation energy of co-pyrolysis are lower than that of separate pyrolysis.Finally,discuss the mechanism of interaction in process of biomass and coal co-pyrolysis,as well as the influence of different factors on the interaction.Analyze the influence mechanism from four aspects about alkali,atmosphere,temperature and heating rate,mainly reflect changes in activation energy,maximum rate of pyrolysis,catalytic reaction,lattice structure and method of carbon atoms,particle structure and so on,thus the interaction show different results ultimately.In this paper,make analysis and comparison for gasification rate of co-gasification and coal gasification.Firstly,get the gasification rate by TG curve of pyrolysis process,then analyze gasification rate of coal in main pyrolysis temperature interval,finally get the relative amount of change on rate between coal gasification rate in co-gasification and coal separate gasification.The coal gasification rate of cotton stalks and coal co-gasification higher about 4.2%to 9.1%than that of coal separate gasification;In sawdust and coal co-gasification process,increased by approximately 8.3%to 10.6%.