Computer Simulation of the Mass and Energy Balance during Gasification of Sugarcane Bagasse

Abstract

This paper investigated the mass and energy balance of the gasification of sugarcane bagasse using computer simulation. The key parameters and gasifier operating conditions were investigated in order to establish their impact on gas volume and conversion efficiency of the gasification process. The heating value of sugarcane bagasse was measured and found to be 17.8 MJ/kg which was used during calculation of the conversion efficiency of the gasification process. Fuel properties and gasifier design parameters were found to have an impact on conversion efficiency of the gasification process of sugarcane bagasse. The moisture content of sugarcane bagasse was varied by 1.14%, 15%, and 25%, respectively. Optimum conversion efficiency was achieved at low moisture content (1.14%) after computer simulation of the gasification process. The volume of carbon monoxide increased at low moisture content. It was also found that maximum conversion efficiency was achieved at reduced particle diameter (6 cm) and at reduced throat diameter (10 cm) and throat angle (25°), respectively, after these parameters were varied. Temperature of input air was also found to have an impact on the conversion efficiency of the gasification process as conversion efficiency increased slightly with increasing temperature of input air.

Assessment of the Influence of Torrefied Biomass Physical Characteristics, Design and Operating Variables on Gasification Efficiency

“…Fuel with high volatile matter content is desirable for gasification. Increased fixed carbon content was also measured for torrefied sugarcane bagasse, a condition that also leads to improved gasification in terms of efficiency [10]. The composition of ash was relatively high as can be observed from Table 3.…”

“…Its hydrogen composition is ca. 4%, which implies that moisture would be made available via hydrogen for the water-gas shift reaction to take place as this is the major reaction that leads to syngas formation during gasification [10]. The low nitrogen content measured implies low formation of NOx, which poses no environmental threats during gasification.…”

“…Detailed description of the gasification simulation programme is presented in a previous publication [10]. The parameters used during gasification simulation process of torrefied sugarcane bagasse are presented in Table 1.…”

“…A 20 MJ/kg of calorific value was measured for torrefied sugarcane bagasse, which is high enough to allude that the gasification of the material may experience increased efficiency because gasification efficiency, among other factors, is based on the energy content of the feedstock [10]. The reason for the high calorific value obtained may be attributed to alteration in chemical properties caused by torrefaction, especially with regards to the reduced oxygen-carbon and hydrogen-carbon ratios.…”

“…Gasification relies on partial oxidation at high temperatures to convert biomass into energy [10]. Many different types of gasifiers have been proposed and used for the conversion of biomass to energy, with each type designed according to feedstock characteristics.…”