Co-gasification Of Yard Waste (YW) And Sewage Sludge (SS) For Enhanced Hydrogen Production

The generation of yard waste has become unavoidable with the expansion of urbanization and the development of urban afforestation in different countries.Sewage sludge generated from domestic and industrial wastewaters treatment plants has become a critical problem for the sustainable development of the environment because it contains heavy metals,toxins,and microbes.The generation of yard waste and sewage sludge has become unavoidable with the expansion of urbanization and rapid growth in population.Thus,advanced,and cost-effective treatment method is required for the safe and environment-friendly disposal of yard waste and sewage sludge.Present study based on the co-gasification of yard waste and sewage sludge individually and at different mixing ratios.This study was conducted in two parts;the first part was based on the TGA-FTIR analysis and the second part was performed in the horizontal tube reactor.There were two main objectives of this study,firstly to find the degradation rate of feedstock and the detection of the evolved volatile species.Secondly,to investigate the influence of temperature and sewage sludge contents on the quality and yield of the gas produced by the experiment under the range of 700-900℃ and 0-100 wt.%.The research revealed that:1.The weight loss rate of yard waste and sewage sludge mixture increases,which promotes the production of volatile compounds and ultimately reduces the residual carbon.There are two weight loss zones in the TG curve,the higher the temperature the higher the weight loss occurred.When the heating rate was 15℃/min,the maximum weight loss occurred about 75%,at the mixing ratio of 5:5 between 310℃ and 477℃.FTIR analysis revealed that CO₂,CO,H₂O,C-O,C-H,C=C,C-O-C and C=O were the main functional groups observed in IR spectra.2.In the gasification experiments of yard waste（YW）,it was noticed that the H₂concentration from was maximized at 800℃ and reached maximum value of 12.34 mole%.Besides,the content of H₂in the gas mixture produced by sewage sludge SS was also maximized at 800℃.Whereas,the co-gasification results,at the optimal temperature（800℃）from single-fraction,showed that the concentration of hydrogen in syngas was increased by the addition of SS in the blends.The H₂ in syngas dramatically increased when the SS content ranged from 0%to 60%and reached the maximal value of 13.91 mole%at 5:5 blend.3.To find out the correlation between theoretical and experimental results,BASIC model was used to predict the experimental result.The theoretical results from the BASIC model showed the good agreement with the experimental results.The model results showed that the H₂ concentration was augmented and maximized at 800℃.Based on the experimental results of this study,biomass gasification is potential energy recovery and waste treatment method,which can bring long term benefits for waste treatment in Pakistan.Biomass gasification is most reliable and promising method for electricity production in rural areas of Pakistan.The estimated electricity production is about 0.44 x1012 kwh from 414.597 million tons of biomass.