The Study Of Biomass In-situ Catalytic Pyrolysis For Hydrogen-rich Gas

Since the depletion of fossil energy,many researchers began their study on clean and renewable energy such as biomass,so as to lower the pressure of energy shortages and realize large-scale industrial applications of biomass energy.Biomass pyrolysis gasification is one of an important research direction for biomass pyrolysis,which is aimed to converting biomass energy into clean,high-quality gases.In the conventional pyrolysis gasification process,there are problems of low concentration of effective gases such as H2 and CO in the pyrolysis gas,and tar will block the pipe during the gasification process,which will affect the continuous process of gasification and other additional problems.In this paper,we focus on improving hydrogen content and reducing tar production effectively during pyrolysis gasification process.Starting from the in-situ catalytic cracking of biomass to produce hydrogen-rich gas and changing the way of carbon deposition.The related experimental study are as follows:1.Ricehusk was taken as raw materials,CaO as capture agent,in which to explore the change of combustible gases in different temperature and different proportion of capture agent in-situ CO2 capture.The results show that when the temperature was at 600?,700?,800? the pyrolysis gas production was 245 ml/g,300 ml/g,340 ml/g,which was significantly affected by temperature,and there is a jump in 700?-800?;At 600?,when CaO:biomass = 1:3,1:4,1:5,1:6 CO2 concentration kept in 22%,the CO2 capture has nothing to do with CaO proportion,the restriction may mainly by temperature;At CaO:biomass =1:4 in 700?,the higher H2 yield 41%and lower CO2 yield 16%was abtained,what's more,the CO2 capture efficency was 64%.However in 800?,because of the cracking of CaCO3,the absorption of CO2 was inhibited,H2 and CO2 yield was 36%,22%,the GC-MS analysis shows that CaO play the role of catalytic cracking instead in this temperature,that is to say catalytic crack of CaO to tar produced in the process of biomass pyrolysis.2.The influence of alkaline metal on biomass pyrolysis to hydrogen-rich gas was investigated in a fixed-bed reactor.The experimental results showed that K2CO3 in potash can catalyze the pyrolysis hydrogen production process of the ricehusk.TG analysis showed that potassium salt can effectively decrease the temperature at which the pyrolysis of the ricehusk begin.The temperature and K2CO3 mass fraction are all factors that affect the hydrogen content.At 600?,650?,the catalytic activity of potassium salt was lower,and the H2 concentration was 11.54%and 19.68%,respectively.The H2 concentration of pyrolysis under the catalysis of K2CO3 at 700 ? reached the highest 42.70%.The content of H2 increased from 20.75%to 35.4%with no addition of K2CO3 to the husk,and the H2 content increased significantly from 20.75%to 35.4%.At 15%,the H2 content had a maximum value of 42.7%.When the mass fraction exceeded 15%,the increase continued.The H2 content no longer increases.3.Catalytic cracking experiments of industrial tars were carried out using nickel-based catalysts under catalytic equipment.The experimental results show that at 800?,the s/c ratio at 2.5:1,the efficiency of catalytic cracking reaction of industrial tars is the best;different catalysts are added to the catalysts.The potassium component can obtain different catalytic effects.When the s/c ratio is 2.5 and the potassium adjuvant content is 15%,the highest H2 generation rate reaches 49.65%.