Iris Publishers- Open access Journal of Engineering Sciences | Simulation of Adiabatic Gasification of Corn Straw using Air-Steam Blends as an Oxidizing Agent

 

Authored by Bonilla Javier

Due to the increase of consumption in the world of energy and the pollution caused by fossil fuel combustion processes, it is necessary to generate new technologies for the use of alternative fuels, allowing to reduce the dependence on fossil fuels such as oil, gas and coal. In general, the combustion processes of fossil fuels produce greenhouse gases which increase the temperature of the environment and the deterioration of the ozone layer. Chemical equilibrium was used to estimate the species produced by adiabatic gasification with different air-vapor mixtures. By running the NASA CEA software (chemical equilibrium with applications), a thermochemical simulation was performed under two parameters: the equivalence ratio (ER) defined as stoichiometric air/air supplied to the reactor (1.5-6) and the steam-fuel ratio (0-1). Thus, the syngas composition showed the following ranges: CO (0% -14.7%), H₂ (0% - 36.7%), CH₄ (0% -4.3%), Co₂ (17% -22.7%). The calorific value of the gases and the energy conversion power were also calculated with the composition of the gases. Then, The Higher Heating Value (HHV) was calculated whose values aim to conclude that syngas generated can be classified as a poor fuel gas since the HHV ranged between 1992 kJ/SATP m³-7537 kJ/SATP m³.

The current and growing consumption of energy and the increase of toxic NOx, SOx and greenhouse gases produced from the combustion of fossil fuels, are problems that require effective solutions that meet the energy needs of society in a sustainable manner. Fuel biomass, which includes energy crops and a wide range of municipal, agricultural and animal waste, serves as renewable resources for energy conversion processes in thermal energy conversion processes such as complete combustion and gasification. The use of biomass in the above mentioned processes does not increase the concentration of Co₂ in the atmosphere because biomass is a carbon neutral fuel resource. For combustion processes, it is advisable to use biomass with high calorific value and low ash content. Biomass with low calorific value results in poor and unstable combustion whereas biomasses with high ash content cause problems in burners and boilers due to the slag and dirt produced. Complete combustion and gasification of biomass with air have been deeply studied during the last decades [1-16].
The biomass gasification is a thermal process to produce syngas which can be an alternative solution since biomass is a neutral fuel in the production of Co₂ [10]. Additionally, biomass can also be used as fuel in combustion processes for power generation; however, these processes usually occur at high temperatures that favor the formation of NOx and SOx [17-19]. The use of biomass (energy crops, agricultural and municipal waste, etc.) as fuel in gasification processes for power generation not only alleviate the high demand for energy but also avoids pollution caused by fossil fuels and inadequate management of waste.

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