Experimental Study On Hydrogen Production By Gasification Of Black Liquor In Vapor Atmosphere

In recent years,with China's economic progress and the continuous improvement of people's living standards,the rapid development of China's paper industry has led to the increasing discharge of paper-making wastewater.If the direct discharge is not disposed of,it will cause serious damage to the environment.Most of the wastewater discharged from paper industry is commonly known as "black liquor".Its composition is complex,environmental pollution is very high,and it is extremely difficult to treat.With the development of economy and the increasing awareness of environmental protection and resource conservation,pulping black liquor containing a large number of organic substances and alkali residues has come into people's sight again.Black liquor is a kind of paper processing waste with great industrial value.The main components of black liquor are various macromolecular organic substances.Black liquor gasifies at appropriate temperatures to produce a large number of gases,including H2,CH4,CO and CO2.The content of combustible gases is very high,which has a broad prospect in industrial applications.How to comprehensively utilize the organic and inorganic substances in pulping black liquor and effectively carry out the utilization of black liquor has become the research focus at home and abroad.Therefore,this paper studies the following four aspects in order.The gasification characteristics of straw pulp black liquor in N2 atmosphere and steam atmosphere were studied in this paper.The experiments of black liquor gasification were carried out at 550,600,650,700,750 and 800 degrees respectively.The gasification results of black liquor in two different atmospheres were compared,and the gasification mechanism was analyzed.It was found that the gasification stability,gas production rate and gas production of black liquor in water vapor atmosphere were all the same.The result of gasification under N2 atmosphere is better than that under N2 atmosphere,so the fluidized medium for the next gasification test is water vapor.After choosing water vapor as the flowing medium for the next black liquor gasification,the effect of adding K2CO3 catalyst on black liquor gasification is explored.The research methods are as follows: four different K2CO3 ratios(5%,10%,15% and 20%)are selected to carry out 20 minute experiments at the above six temperatures.The experimental results show that the optimum catalyst ratio is 10%and 15%.At the same time,the influence of the black liquor flow rate on the black liquor gasification is tested.It is found that the fluidization state in fluidized bed is inhibited when the black liquor flow rate is too high.By combining the above factors,the black liquor gasification can be obtained under steam atmosphere,temperature 800C,0.2g/s,10%K2CO3 ratio.The maximum volume fraction of H2 reached 67.1%,and the maximum volume fraction at stable condition was 62.5%.