Study On The Codensifaction Behavior Of Pyrolysis Products Derived From Corn Stalk And The Combustion Characteristics Of The Composite Pellet Fuel

Biomass as a sustainable and green energy has the potential for replacing fossil fuel.On the one hand,biomass with low price and huge yield can benefits for reducing the cost of fuel.On the other hand,this fuel contributes to decrease the greenhouse gas emission.But these disadvantages,low heating value,low energy density,fragility and weaker water resistance,limite the development of biomass as a large scale of commercialized fuel.The improvement of biomass in fuel characteristics is accessible for realizing resource utilization of biomass.The effect of biomass co-densification on fuel properties has been investigated in this article.The factor significance of pyrolysis temperature,holding time and particle size on biochar higher heating value(HHV)and energy yield(EY)has been discussed and the biochar producing parameters for optimum HHV and EY have been optimized.Further,this study discussed the influence of bio-oil and waste cooking oil as binders and biochar as an additive on logistical,storage and combustion properties of corn straw pellet fuel.The detailed information about biomass pellet fuel has displayed in this research,which has the practicing value for development of pellet fuel.The main results are as follows.Through orthogonal experiment,based on the variance and range methods,the pyrolysis temperature is the significance factor for both higher heating value and energy yield,while the resident time and particle size are non-significance factors.Meanwhile,the influence of resident time is prior to particle size.Besides,corresponding to index of HHV and EY,the optimum production process was 700?,30 min,0.6?0.8 mm and 200?,30 min,0.4?0.6mm,respectively.Under the optimum parameter,the higher heating value of biochar can increase to 30.09 MJ/kg and the energy yield can rise to 104.20%.The corn straw pellet with biochar was produced by respectively mixing apple tree branch bio-oil(APO)and waste cooking oil(WCO).Based on durability and energy density,the optimum formulations were selected.Pellet B6-40-40 with the highest HHV to 22.15 MJ/kg and highest energy density to 20.50 GJ/m~3 consists of 6.25 wt%bio-oil,10.52 wt%water,41.67 wt%corn straw and 41.67 wt%biochar.For the pellet C10-50-30,the HHV increases to 21.34 MJ/kg and the energy density rises to 19.03GJ/m~3,which contains 10 wt%bio-oil,10wt%water,50 wt%corn straw and 30 wt%biochar.According the content of biochar in the pellet fuel,the apple tree branch bio-oil presents a stronger binding effect.The water resistant of the biomass pellet fuel has been strengthened by co-densification with biochar and hydrophobic binder.The B6-40-40 just absorb 4.53 wt%water in total 30 h,which is lower than C10-50-30,which indicates that the pellet B6-40-40 is apt for long-term storage and long-distance transportation.Adding biochar contributes to carbon enrichment and is help for improve the fixed carbon content.Therefore,the B6-40-40 has higher fixed carbon and lower volatile matter than C10-50-30.The results cause the ignite temperature fall to235?,lower than C10-50-30.Compared with waste cooking oil,the apple tree branch bio-oil can construct a stronger pelleting pattern that remarkably enhance the logistic and combustion characteristics.