Experimental Study On Gasification Characteristics Of Char In Endepul Gasifier By TGA

Coal gasification belongs to the field of chemical industry. A common problem is the high combustible content in fly ash of gasifier. To solve the problem, a method of mixing fly ash and coal powder with a certain ratio to secondary gasification is developed in this paper, and a comprehensive study of Endepul gasifier’s reactive characteristics of fly ash and coal chars. In this paper, thermo gravimetric analysis is adapted to study Endepul gasifier’s reactive characteristics of fly ash and coal chars under CO₂ atmosphere at four different heating rates, the gasification reaction kinetics characteristics is analyzed by DAEM Miura integral method, it is first to use 3-DAEM to analyze gasification reaction kinetics characteristics, which can provide theoretical guidance for engineering application.First of all, in this paper, Huolinhe lignite and Shenhua lignite fly ash from the Endepul gasifier scene and Shenhua lignite chars made in laboratory is taken as study subject, TGA is used to study their reactive characteristics under CO₂ atmosphere at four different heating rates. It is found that the conversion curve and conversion rate curve of Huolinhe lignite and Shenhua lignite fly ash are basically in coincidence, however there’s big difference between Shenhua lignite fly ash and Shenhua lignite coal chars for the conversion curve and conversion rate curve. Shenhua lignite fly ash conversion rate curve has an obvious evidence of segmentation, as a supplement, it’s maximum conversion rate is obviously lower than Shenhua lignite coal chars.This article analyzed the gasification reaction kinetics of Huolinhe lignite fly ash and Shenhua lignite fly ash by Miura integration method of distributed activation energy model. The result shows: with conversion efficiencies increasing, activation energy curves of Huolinhe lignite fly ash and Shenhua lignite fly ash tend to decrease on the whole and slowly rebound at 1170 K to a peak value. The maximum activation energies of Huolinhe lignite fly ash, Shenhua lignite fly ash and coal coke are respectively 500 k J/mol, 460 k J/mol and 233 k J/mol and the minimum activation energies are respectively 170 k J/mol, 190 k J/mol and 109 k J/mol.Moreover, this paper uses the 3-DAEM to analyze the kinetics of Huolinhe lignite fly ash, Shenhua coal fly ash and coal char gasification. When the 3-DAEM is fitted, three stages of primary pyrolysis, secondary pyrolysis and char gasification displayed. The primary pyrolysis stage of Huolinhe lignite fly ash and Shenhua lignite fly ash is obvious, while it is not obvious for Shenhua lignite char.Finally, the gasification characteristics of Sanxing coal and coal char in the presence of CO₂ was investigated by the method of thermogravimetric analysis. And meanwhile two methods of the Mirua integration on distributed activation energy and the 3-DAEM were applied to do the gasification kinetics analysis. According to the conversion curve of Sanxing coal, there obviously are two parts divided including pyrolysis control field and gasification control field, and there is no significant subsection on the conversion curves of coal char at 500℃and coal char at 850℃. The maximum activation energy value of Sanxing coal, coal char at 500℃and coal char at 850℃ is 650, 250 and 260 k J/mol respectively, the corresponding minimum is 156, 148 and 147 k J/mol respectively.Endepul gasifier fly ash can carry out secondary gasification but the reaction activity was lower than that of coal. It is recommended that secondary gasification reaction of fly ash mixing with coal powder should occur in entrained flow gasifier of the higher operating temperatures.