Briquetting Of Baiyinhua Lignite Char With Biomass And Its Combustion Characteristics

In this paper, both cold briquetting process and hot briquetting process of biomass with Baiyinhua(BYH) lignite char, prepared from lignite by low temperature pyrolysis at500℃were investigated. And co-combustion characteristics of white pine sawdust with BYH lignite char were introduced using thermo-gravimetric analysis technique. Briquetting of lignite char with biomass could not only solve the difficulty of inconvenience of long-distance transportation due to small particle size of lignite char, but also make full use of biomass resources in our country.The result of cold briquetting process of BYH lignite char with biomass (white pine sawdust and fraxinus mandshurica sawdust) showed that:Drop strength of bio-briquette by using white pine sawdust as binder was larger than that of bio-briquette with fraxinus mandshurica sawdust in the same conditions. In cold briquetting process, drop strength of bio-briquette was93.63%, relax density was911.63kg/m3with the addition of white pine sawdust being50%, briquetting pressure being120MPa, particle size of white pine sawdust being less than0.5mm and water content of white pine sawdust being12.38%.The result of hot briquetting process of BYH lignite char with white pine sawdust showed that:Hot briquetting process could not only lessen the addition of white pine sawdust and briquetting pressure, but also increase the relax density of bio-briquette in contrast to cold briquetting process. In hot briquetting process, drop strength of bio-briquette was95.74%, compressive strength was14.1MPa, relax density was983.57kg/m3, when the addition of white pine sawdust was30%, briquetting pressure was80MPa and briquetting temperature was280℃. In addition, the bio-briquette formed by hot briquetting process had good waterproof performance. The bio-briquette could still maintain the integrity of the block after immersing in the water for24hours, and had high immersion strength.The experiment of co-combustion characteristics of BYH lignite char with white pine sawdust demonstrated that:With the increase of the addition of white pine sawdust, comprehensive index of combustion characteristics of mixed fuels increased gradually, and so did the peak of maximum rate of combustion, whereas burnout temperature decreased. However, ignition temperature and temperature of maximum rate of combustion changed a little with the increase of the addition of white pine sawdust. Coats-Redfern integration method was used to establish the kinetic equation of the co-combustion of BYH lignite char with white pine sawdust. The fitting kinetic equations had high correlation coefficients at high temperature stage, whereas with low correlation coefficients at low temperature stage. In addition, with the increase of the addition of white pine sawdust, the total amount of SO2emissions decreased gradually, while the total amount of NOx emissions increased in air atmosphere.