Experimental Investigation of Pyrolysis Process of Agricultural Biomass Mixture

This paper describes an experimental investigation of pyrolysis process of agricultural biomass mixture, without the addition of inert gas. The mixture consists of corn stalk, wheat straw, soy straw and oat straw with equal mass fractions. During the experiment, the mass of biomass sample inside the reactor was 10 g with a particle diameter of 5-10 mm. The sample in the reactor was heated in the temperature range of 24-650ºC at average heating rates of 21, 30 and 54ºC/min. The sample mass before, during and after pyrolysis was determined using a METTLER P1000 digital scale. Experimental results of the sample mass change indicate that the highest yield of pyrolytic gas, achieved at 650ºC, was in the range from 74 to 81%, while char yield ranged from 19 to 26%. Heating rate of biomass mixture sample has significant influence on the pyrolytic gas and char yields. It was determined that higher heating rates in the reactor induce higher yields of pyrolytic gas, while the char mass reduces. Condensation of pyrolytic gas at the end of the pyrolysis process at 650ºC produced 1.3-1.8 g of liquid phase. The results obtained represent a starting basis for determining material and heat balance of pyrolysis process as well as agricultural biomass pyrolysis equipment

Qualitative analysis of coal combusted in boilers of the thermal power plants in Bosnia and Herzegovina

In this paper we have looked into the qualitative analysis of coals in Bosnia and Herzegovina (B-H). The analysis includes the following characteristics: moisture (W), ash (A), combustible matter (Vg) and lower heating value (Hd). From the statistic parameters we have determined: absolute range (R), arithmetic mean (X), standard deviation (S) and variations coefficient (Cv). It has been shown that the coal characteristics (W, A, Vg, Hd) have normal distribution. The analysis show that there are considerable deviations of ash characteristics: moisture (36.23%), ash (34.21%), combustible matter (16.15%) and lower heating value (25.16%) from the mean value which is shown by the variations coefficient (Cv). Large oscilations of mass portions: W, A, Vg and Hd around the mean value can adversely influence the function of a boiler plant and an electric filter plant in thermal power plants in B-H in which the mentioned types of coal burn. Large ash oscilations (34.21%) around the mean value point out to the inability of application of dry procedures of desulphurisation of smoke gasses (FGD) due to the additional quantity of ash. It has been shown that the characteristics of Bosnian types of coal do not deviate a lot from the characteristics of coal in the surrounding countries (coals of Serbia and Monte Negro). The results can be used in analysis of coal combustion in thermal power plants, optimisation of electrical-filtre, reduction of SO2 in smoke gas and other practical problems