Study On Preparation And Performance Of Civil Cow Dung Briquette

The inefficient use of domestic solid fuel has always been a major livelihood and environmental issue.Biomass briquette is an economical and feasible way to effectively solve the problem of civil fuel pollution in present,which combined coal with flammable biomass,and has obvious energy-saving and environmental protection effects compared with traditional briquette.In this paper,cow dung,anthracite and high sulfur coal were used as raw materials,sodium humate and red clay as binder,the mixture of potassium nitrate as combustion promoter,the compound of aluminium hydroxide as smoke suppressor,civil cow dung briquette(CDB)was successfully prepared by the cold-press briquetting technology and its quality index and combustion characteristics were tested.In addition,the effect of Ca-based desulphurizer on desulphurizing property of cow dung/high sulfur coal composite briquette was also studied.The main research contents were as follows:1.CDB was prepared with the cold-press briquetting technology by using cow dung and anthracite were used as raw materials,and sodium humate and red clay as binder.Its physical properties was studied.When the mixing ration of cow dung and anthracite is 1:3?4(wt),sodium humate mixed with red clay at a mass ratio of 3:1and the dosage is about 17.0%and molding water content is about 25.0%,the calorific value,volatile content and ash content of briquette are 19.8 MJ/kg,17.1%and 28.6%,respectively.The compression strength is 246 N/cm²and it can be stored and transported at natural air drying at room temperature for about 29 h.Moreover,adding a proper amount of odor masking agents such as?-phenylethanol,geraniol and eugenol to the raw materials can effectively mask the odor of CDB during combustion.2.The effect of additives on the combustion performance of CDB was studied.When the dosage is about 6.0%of the mixture of potassium nitrate,the comprehensive combustion characteristic index(S_N)of CDB is2.11×10^-7%²·min^-2·?^-3,the stable burning characteristic index(D_W)is4.77×10^-5%·min^-1·?^-2and the burnout index(C_b)is 50.95%²·min^-1.When the dosage is about 4.5%of the cmixture of alumium hydroxide,the specific optical density(D_S)of CDB is 3.58.Compared with CDB without additives,it has better combustion performance,in which the ignition point,burning temperature and smoke emission decreased,and the combustion characteristic indexs and the maximum volatile release rate increased.3.The composite briquette was prepared by using cow dung and high sulfur coal as raw materials,and acidified Ca O and red clay as desulphurizing agent.The desulphurizing property of cow dung/high sulfur coal composite briquette was studied by using Ca O acidified with tartaric acid and red clay as desulphurizer.The desulphurization rate of cow dung/high sulfur coal composite briquette can be reached to 84.16%when adding of 6.5%acidified Ca O with red clay(4:1,wt),and the sulfur emission during combustion is completely suitable to the Standard.The reason for the increase of desulfurization rate was analyzed by SEM,XRD and BET analysis.After acidification,the particle size distribution of Ca O is uniform,the specific surface area is increased and sulfate complexes with good thermal stability are formed in the process of sulfur fixation with red clay.