Study On The Combustion Characteristics Of Fuel Charcoal Prepared From Biomass

Biomass is the only renewable resource which can be used as alternative energy sources to produce fuel and industrial chemicals. Biomass energy has the properties of renewability, storability, widely distribution, huge reserves, low pollution and zero emission of CO2. Hence, the development and utilization of biomass energy can effectively alleviate the crisis of energy and environmental problems. However, the utilization of biomass energy is low and its usage is mainly concentrated in the rural areas as cooking energy which energy conversion rate is very low. More and more attentions were paid to biomass energy utilization with the non-renewable fossil fuel resources shrinking and environment worsening. Biomass carbonization process is a kind of biomass energy conversion technology and it is the most competitive bio-energy utilization way because the process is simple and various products can be produced.Therefore, biomass carbonization process was chosen as the object of our study. In the paper, the carbonization processes of the biomasses chosen and the qualities of the resulted chars were addressed detailedly. In addition, the combustion characteristics and the combustion kinetics of the char product of the biomass were studied. The main contents of this paper is shown as follows:Firstly, in order to investigate the influence of carbonization temperature on the yield, components and combustion characteristics of the resulted biochars, the carbonization experiments of the several kinds of the biomasses were carried out and the industrial analyses and combustion characteristics of the biochars had been studied in this paper. The results indicate that with the increasing of carbonization temperature,the yields of the biochar and its volatile yield and combustion reactivity decreases, its fixed carbon yield increases and its calorific value increases at first and then decreases.Secondly, the thermogravimetric experiment of the biochar was carried out to investigate its combustion process. A model of gas-solid reaction had been used to deduce the mechanism function of biochar combustion reaction kinetics and its kinetic parameters was solved by using the integral method of Coats-Redfern method. The results show that the reaction mechanism of the biochars is controlled by the chemical reaction on the spherical surface, and the reaction activity of biochar decreases with the carbonization temperature increasing.Finally, the quality and the combustion characteristics of biochar have been compare with the commercial fuel charcoal to analysis the practicability of the biocharutilization as fuel charcoal. Furthermore, the practicability of the barbecue charcoal prepared from and the mixed biomass has been analyzed. The results indicate that cotton stalk biochar can be used as fuel for daily-life, sawdust biochar and bamboo sawdust biochar can be used as the feedstock for metallurgical industry. Cotton stalk can be used to produce barbecue charcoal briquette and the biochar produced from the mixed biomass in a certain mixing ratio can be used to produce barbecue charcoal.