Low Temperature Co-pyrolysis Of Brown Coal And Ulva

Nowadays, with the shortage of fossil fuel resources and the serious environmental pollution and resource waste caused by exploitation, the task of seeking renewable alternative energy resources and utilizing low rank coal cleanly and efficiently is urgent on the basis of abundant low rank coal in our country. Recently, much attention has been paid to low-temperature co-pyrolysis of biomass and low rank coal attempting to improve the pyrolysis conversions and the quality of pyrolysis oil.The algae ulva(SC) and Australia lignite(AL) were selected as raw materials.Experiments were undertaken in home-made pyrolysis furnace with the total sample 10 g(SC ratio 0%, 10%, 20%, 30%, 40%, 50%, 100%). Analyzed the change of products yield with SC ratio on the basis of parallel experiments. A thermogravimetric analyzer was used to study the pyrolysis mechanism and impact of SC on the pyrolysis process.Under the experimental conditions, results are as follows:(1) Results of low-temperature pyrolysis show that with the increase of SC blending ratio, the gas yield increased gradually and char yield decreased. The pyrolysis oil yield showed a trend of decrease after the first increase, and the peak value was 12.50% at about 30% ratio. Compared with coal pyrolysis alone, the oil yield increased by 20.64%.(2) GC- MS show that alkanes in pyrolysis oil of 30%mixed samples, compared with AL pyrolysis oil, increased by 23.54% from 13.51% to16.69%, improving the oil quality. The content of alcohols and organic acids decreased obviously, improving the stability of pyrolysis oil and reducing its corrosion for the equipment.(3) FT-IR show that methyl stretching vibration peak weakened and skeleton of aromatic ring vibration peak got red-shifted. It can be concluded that the whole process involves the dealkylation, ring opening reaction and condensation reaction, etc.(4) TGA show that the initial pyrolysis temperature of 30% SC ratio sample is 21.94℃ ahead of AL pyrolysis alone and the actual residual weight is lower than theory weight, indicating that SC promoted the precipitation of volatiles. The co-pyrolysis reactions were in accordance with first order kinetic equation model. Both Ea(12.13kJ/mol)and A(5.54min-1) of co-pyrolysis decreased compared with those of AL pyrolysis alone. There exists compensation effect between Ea and A. SC increased the reactivity and reduced the reaction rate.