Gasifier

Energy, 2007

Biomass has great potential as a clean, renewable feedstock for producing modern energy carriers. This paper focuses on the process of biomass gasification, where the synthesis gas may subsequently be used for the production of electricity, fuels and chemicals. The gasifier is one of the least-efficient unit operations in the whole biomass-to-energy technology chain and an analysis of the efficiency of the gasifier alone can substantially contribute to the efficiency improvement of this chain. The purpose of this paper is to compare different types of biofuels for their gasification efficiency and benchmark this against gasification of coal. In order to quantify the real value of the gasification process exergy-based efficiencies, defined as the ratio of chemical and physical exergy of the synthesis gas to chemical exergy of a biofuel, are proposed in this paper. Biofuels considered include various types of wood, vegetable oil, sludge, and manure. In this study, exergetic efficiencies are evaluated for an idealized gasifier in which chemical equilibrium is reached, ashes are not considered and heat losses are neglected. The gasification efficiencies are evaluated at the carbon-boundary point, where exactly enough air is added to avoid carbon formation and achieve complete gasification. The cold-gas efficiency of biofuels was found to be comparable to that of coal. It is shown that the exergy efficiencies of biofuels are lower than the corresponding energetic efficiencies. For liquid biofuels, such as sludge and manure, gasification at the optimum point is not possible, and exergy efficiency can be improved by drying the biomass using the enthalpy of synthesis gas.

Renewable and Sustainable Energy Reviews, 2011

Biomass is a unique renewable energy fuel in that unlike other renewables, it is naturally available as a solid fuel, but can be converted into liquid or gaseous fuels. The world in 2005 used around 48 EJ of biomass energy, nearly all of which was combusted at low thermal efficiency as fuelwood in developing countries. Around 4.6 EJ was used in modern biomass systems, either as liquid transport fuels or as a solid fuel for boilers in power stations or heating units. At present, very little is gasified. The future use of gasified biomass will increasingly depend on its ability to deliver higher greenhouse gas savings at lower costs than other ways of using bioenergy. Because of the high efficiencies possible for combined cycle gas turbines, the potential for gasification is considerable, but cost reductions and further technical progress are still needed. Its potential could be enhanced if gasification combined with carbon capture becomes feasible.

2019

The gasification process can be considered as one of the greatest conservative techniques in the transformation of biomass because of certain crucial factors such as the consideration of space, reduction of substantial waste volume, flexibility of fuel used, as well as the recovery of energy. The general process of gasification inclines to involve the incomplete burning of the carbon-based part of fossil fuels, which forms an abundant flammable gas in the presence of hydrogen, carbon monoxide and methane or some saturated hydrocarbon gases. When we consider the process of gasification, the parameters deemed to affect its performance, including the type of catalyst used, gasifying agents, biomass ratio and temperatures, as well as the type of raw materials. The primary purpose of this paper is to address the gasification process, including the types of gasifier designs like the fluidized bed, downdrafts, and updrafts. It’s also responsible for addressing the production of tar from th...

Bioresource technology, 2002

The conversion of biomass by gasification into a fuel suitable for use in a gas engine increases greatly the potential usefulness of biomass as a renewable resource. Gasification is a proven technology and can be operated either as a simple, low technology system based on a fixed-bed gasifier, or as a more sophisticated system using fluidized bed technology. The properties of the biomass feedstock and its preparation are key design parameters when selecting the gasifier system. Electricity generation using a gas engine operating on gas produced by the gasification of biomass is applicable equally to both the developed and the developing world.

The World is facing crucial time for energy due to consumption of fossil fuels (natural gas, coal, and oil), rise in fuel price, and unacceptable environmental effect in recent years. Biomass is a renewable potential energy source which can reduces dependency on fossil fuels. Biomass is available in various forms throughout year in India. It accumulates solar energy by photosynthesis method from sunlight. Gasification is a chemical process that converts carbonaceous material such as biomass and coal into gaseous fuel or chemical feedstock. This gaseous fuel is known as producer gas or syngas which contains CO2, H2, CO, H2O, CH4 and N2 compounds. An attempt has been made to give basic idea about gasification, gasification mechanism, types of gasifier and characteristics of different biomass in this paper.

Biomass gasification is considered as one of the most promising thermo-chemical technologies but the gasifier unit renders itself to internal inefficiencies. This paper addresses the gasifier performance analysis using the exergy analysis modeling which utilizes both the first and second laws of thermodynamics. An exergy model incorporating a chemical equilibrium model is developed. Gasification is envisaged to be carried out at atmospheric pressure of 1 bar with the typical biomass feed, sugarcane bagasse, represented by the formula CH1.42 O0.65 N0.0026 at the temperature range of 800-1400K. In the model, the exergy contained in the biomass was converted into chemical exergy of the product gas, physical exergy, the rest was the unavailable energy due to process of irreversibilities (losses). The model evaluated the product gas molar concentrations and efficiency. The results from the model showed that the mole concentration of H2 increased from 9.8% to 23.7% and the formation of CO...

Gasification can be considered as one of the most conventional techniques in the conversion of biomass because of some crucial factors, such as the consideration on space, reduction of the substantial waste volume, the flexibility of the fuel used as well as the recovery of energy. The overall process of Gasification tends to involve the partial combustion of the organic part of the fossil fuels, which forms an abundant combustible gas in the presence of carbon monoxide, hydrogen, and some saturated hydrocarbon gases, or methane. When we consider the process of Gasification, the parameters deemed to affect its performance, including the catalysts, Gasifying Agents or the Biomass ration and temperatures, as well as the type of raw materials are reviewed and discussed in this study. The primary purpose of this paper is to address the Gasification Process, including the Types of Gasifiers System Designs like the Fluidized bed, Downdrafts, and the Updrafts. It’s also responsible for addressing the production of tar from the process of Gasification. The paper explores and discusses all the primary, secondary and tertiary types of tar while touching on the Gasification Modeling Methods and Equations used in the Modeling.

Biomass gasification is a widely used thermochemical process for obtaining products with more value and potential applications than the raw material itself. Cutting-edge, innovative and economical gasification techniques with high efficiencies are a prerequisite for the development of this technology. This paper delivers an assessment on the fundamentals such as feedstock types, the impact of different operating parameters, tar formation and cracking, and modelling approaches for biomass gasification. Furthermore, the authors comparatively discuss various conventional mechanisms for gasification as well as recent advances in biomass gasification. Unique gasifiers along with multi-generation strategies are discussed as a means to promote this technology into alternative applications, which require higher flexibility and greater efficiency. A strategy to improve the feasibility and sustainability of biomass gasification is via technological advancement and the minimization of socio-environmental effects. This paper sheds light on diverse areas of biomass gasification as a potentially sustainable and environmentally friendly technology.