New Correlations for Coal and Biomass Pyrolysis Performances with Coal-Biomass Type Number and Temperature

Abstract

Abstract. The pyrolysis of coal and biomass is generally reported as the mass yield of released chemicals at various temperatures, pressures, heating rates and coal or biomass type. In this work, a new coal-biomass type number, N CT , is introduced. This number is constructed from the mass fractions of carbon, hydrogen, and oxygen in the ultimate analysis. This number is unique for each coal or biomass type. For 179 different species of coal and biomass from the literature, the volatile matter mass yield can be expressed by the second order polynomial function ln(N CT ). This unique correlation allows the effects of the temperature and heating rate on the volatile yield Y VY for coal and biomass to be empirically correlated as well. The correlation for the mass fraction of each chemical component in the released volatile matter correlation is obtained from the Y VY correlation. The weight factor for some of the components is constant for the variation of N CT , but not for others. The resulted volatile matter and yield correlations are limited to atmospheric pressure, very small particles (less than 0.212 mm) and interpreted for wire-mesh pyrolysis reactor conditions and a nitrogen gas environment.

Thermodynamics simulation performance of rice husk combustion with a realistic decomposition approach on the devolatilization stage

“…The ultimate and proximate analysis results are given in Table 1. The proximate analysis procedure is performed at 900 o C follows ASTM 3175-07 procedure, whereas the combustion occurred at = 700 o C. A volatile enhancement factor , which is commonly found in 0.8-1.3, plays a role to correct the devolatilized product at a temperature beyond 900 o C [10,11]. To determine , the biomass type number ( ) should be calculated first as in equation 1a.…”

“…Subsequently, equation 1c is a temperature correction function, 5 ( ) in o C unit, which is later employed in equation 1d to obtain the predicted devolatilized products mass fraction ( ′ ). Afterward, is calculated following equation 1e [10,11]. Rice husk devolatilization produces gases, tar, and char.…”

“…Tar was assumed to consist of C16H18, C10H14O2, C7H8O, and C9H7N. Char was presumed to contain only C. Each product amount is determined from equation 2 and should consistent with the value from dry-ash-free basis of proximate and ultimate analysis [10,11].…”

“…Meanwhile, the rice husk combustion modelling study in a grate bed furnace had a maximum combustion temperature of 1406.85 o C and flue gas exhaust temperature of 693.85 o C with the composition of N2, CO, CO2, H2O, and remaining O2 [9]. The thermodynamics study from the research papers and well-established textbooks mostly proposed that at the devolatilization stage, biomass will decompose to C, H, O, N elements prior to being oxidized to form flue gas [10][11][12]. This approach is simple but quite unrealistic so that it should be developed with a more realistic one.…”

Thermal decomposition of agricultural and food residues: Comparison of kinetic models

“…[6,[15][16][17][18][19][20][21] Empirical correlations are a further class of models, which can include also complex formulations such as Artificial Neural Networks. [22][23][24] They require a dataset of qualified experimental results to be trained but model relations are simple and the computational cost is low. They should be applied within the range of conditions (temperature, heating rate, and fuel composition) used for validation.…”