Investigation Of Pakistani Typical Biomass For Production Of Bio-oil And Upgradation Under Fast Pyrolysis

Pakistan is a developing economy with agriculture and industry contributing 18.86%and 20.91%of GDP,respectively.Improving lifestyles,population growth and rapid urbanization have led to a continuous increase in demand of energy.On average,this demand-supply gap amounts to 5000 MW and touches a peak of 7000 MW in the month of July when scorching heat increases energy requirements for cooling.This shortfall causes losses of 4-7%GDP.A perpetual annual increase of 8-10%has been observed.Energy mix of the country shows 61%share of fossil fuels while negligible 1%is contributed by renewables.This situation calls for increase of renewables' share in energy mix.Biomass,widely regarded as a promising resource of renewable energy,is abundantly available in Pakistan.About half of household energy(cooking and heating)requirements in rural areas are fulfilled by fuelwood and 34%by animals' waste and crop residues.However,availability of fuelwood is reducing as the rate of growth of forests has shrunk by 8.8%.Major crop harvesting residues include cotton stalks,wheat straw,rice straw,sugarcane trash and corn stalk having production amount of 49.4,34.581,16.75,7.83 and 5.325 million tons,respectively.Collective processing residues per annum of these crops amount to 25.271 million tons having power generation potential of 61838 GWhth annually.Conversion of biomass into bio-oil possesses impressive potential of providing carbon neutral energy and is adoptable.This thermochemical conversion is carried out through pyrolysis process in the absence of oxygen at a high temperature.It has been estimated that Pakistani crop harvesting residues has potential to generate 64 million tons of bio-oil annually,if properly and efficiently managed.In this study,pyrolysis-gas chromatography/mass spectrometry(Py-GC/MS)was applied to reveal the product distribution while carrying out pyrolysis of agricultural residue at different temperature levels.To best of the author's knowledge,this is the first detailed investigation of Pakistani biomass under fast pyrolysis with Py-GC/MS.The decomposition of typical biomass was started at low temperature while the maximum desired pyrolytic products capable to produce bio-oil and other valuable chemicals were achieved at 400-500 C.Based on the results,the effect of pyrolysis temperature on pyrolytic product distribution,formation patterns of important products and the possible pyrolytic pathway were discussed.Furthermore,this study employed Py-GC/MS to assess the impact of catalysts on pyrolytic activity while using transition metal nitrides(TiN,ZrN,and W2N)as catalysts.Effects of multiple factors like catalysts,catalyst to biomass(C/B)ratio and pyrolysis temperature on pyrolytic products were carefully investigated to improve fuel properties of pyrolysis oil.The results showed that titanium nitride(TiN)substance with feedstock significantly fostered cleavage of lignin to produce phenolic compounds.It also devolatilized holoceliulose to produce organic volatile compounds by reducing linear aldehydes while increasing furans and cyclopentanones.The maximum volatile product contents were recorded at 500 ? with best C/B ratio 1.It was further noted that yield of maximum phenolics,cyclopentanones and furans produced through catalytic process were 1.53,1.37 and 1.8 times higher than those produced through non-catalytic process,respectively.Linear aldehydes during catalytic process were reduced expressively by 3.32 times compared to non-catalytic process.The maximal yield of stable phenolics obtained from the catalytic process was 2.31 times higher than from non-catalytic process.The study revealed encouraging results indicating promising utility of biomass to produce energy and bio-oil.It cannot only help curtail energy crisis and increase share of renewables in energy mix but can also lead to prevention of open air burning of this valuable waste.Titanium nitride was identified as most efficient catalyst for production of upgrade bio-oil through increasing phenolics,furans and cyclopentanones while decreasing anhydrosugars,aldehydes and acids.The excellent capability of TiN to lower oxygen content and unstable functional groups indicates a huge potential of future research on upgradation of bio-oil for industrial and commercial utilization.