Study On Energy Utilization Technology Of Straw Pyrolysis

With the rapid development of world economy and the increase of population,energy shortage and environmental problems became more and more serious.Energy and environmental protection have become a key factor that restricts the development of social economy.The economic is more developed,the demand for energy is more larger.Traditional energy such as coal,oil,natural gas is non-renewable,the exploitation of them has already not satisfied the human demand for energy,so a new type of energy is urgent to solve this contradiction.As a renewable energy,biomass energy is expected to solve the problem of energy shortage in the future.Among them,the crop straw is a kind of agricultural waste that has a large production,what can be dealt with corresponding technical means to become a good energy.Traditional processing methods such as direct combustion or carbonization have serious pollution to the environment,and energy utilization efficiency is low too,so a new technology to deal with crop straw is needed.In this paper,I studied the pyrolysis of crop straw,which made a reference for efficient utilization of the crop straw.The concrete research content is as follows:First we collected crop straw?such as cotton,rice straw,corn stover?from Wuhan Dong xihu Dstrict dongshan farm,then made a pretreatment and corresponding foundation characteristic analysis.Then we made pyrolysis experiment in the homemade vertical tube furnace,investigated the influence of the types of biomass materials,pyrolysis temperature and pyrolysis time on the pyrolysis characteristics,the results shown that the pyrolysis efficiency of cotton straw is much higher than rice straw and corn stover,higher pyrolysis temperature increases the content of hydrogen and carbon monoxide gas in the gas and gas yield;the longer the pyrolysis time is,the more completely biomass pyrolysis,the gas production and the quality of the gas keep unchanged after 30 min pyrolysis.Due to the serious pollution of tar in gas produced by the straw pyrolysis,the catalytic pyrolysis technology was adopted to solve the problem of tar pollution in the pyrolysis process,at the same time improve the quality of the gas.For this reason,this article firstly researched and developed the ceramsite loaded nickel-based catalysts,namely with the ceramsite as the support,the homogeneous precipitation was adopted to prepare four kinds of catalyst,they respectively are Ni-Fe/Creamsite,Ni-Co/Creamsite,Ni-Cu/Creamsite and Ni-La/Creamsite.Technology means such as XRD?SEM?BET and FT-IR were applied to characterize the catalysts and the supports,the results showed that the active components of the four catalysts are nanometer grade,and the active component respectively are NiO?Fe₂O₃,Co₂NiO₄?Co₃O₄?NiO,(Cu_0.2Ni_0.8)O?NiO?CuO,La₂O₃?NiO?LaNiO₃,and ceramsite is mainly composed of quartz and olivine and minor spinel composition;BET analysis showed that four kinds of catalysts have high specific surface area and pore structure,and have the potential to be used as catalyst for the catalytic pyrolysis of straw.Finally the crops straw catalytic pyrolysis experiment was carried out,the effects of different variety of catalyst,pyrolysis temperature,pyrolysis time on gas production and the gas composition were studied,the results show that Ni-Fe/Creamsit catalysts have good catalytic pyrolysis efficiency,the catalytic efficiency of catalysts were arranged from high to low as Ni-Fe/Ceramsite> Ni-La/Ceramsite> Ni-Co/Ceramsite> Ni-Cu/Ceramsite.Higher catalytic pyrolysis temperature is beneficial to improve the quality of fuel gas,and improve the content of combustible gas in the gas.When the temperature was 900?,the gas yield was 83.53%,at the same time the content of carbon monoxide and hydrogen also reached maximum.So under the experiment condition,after pyrolyzing for 20 min,production rate of gas and gas composition basically remained unchanged,so catalytic pyrolysis has been basically completed after 20 min.