A one-dimensional, unsteady mathematical model is presented of fixed-bed countercurrent wood gasifiers, which couples heat and mass transport with wood drying and devolatilization, char gasification, and combustion of both char and gas-phase species. The model is used to simulate the structure of the reaction fronts and the gasification behavior of a laboratory-scale plant as the reactor throug...

Gasification was chosen as one of the more conventional methods for conversion of biomass due to some important reasons such as space consideration, flexibility of fuels used, reducing the volume of solid waste and recovery of energy. Essentially, the process of gasification involves partial combustion of the organic part of the fuels to combustible gas rich in carbon monoxide, hydrogen and som...

In recent years, hydrogen production from biomass has been optimized in fluidized bed conditions, and the steam gasification has become an area of growing interest because it produces a gaseous fuel with relatively higher H2 content which could be used in fuel cells, a new technology for the future to produce power in a much cleaner manner. The equivalence ratio is one of the most important ope...

Gasification is one of the promising technologies to convert biomass to gaseous fuels for distributed power generation. However, the commercial exploitation of biomass energy suffers from a number of logistics and technological challenges. In this review, the barriers in each of the steps from the collection of biomass to electricity generation are highlighted. The effects of parameters in supp...

Hydrogen is an important chemical in many industries and it is expected to become one of the major fuels for energy generation in the future. Unfortunately, hydrogen does not exist in its elemental form in nature and therefore has to be produced from hydrocarbons, hydrogen-containing compounds or water. Above its critical point (374.8C and 22.1MPa), water has lower density and viscosity, and a ...

Limited information is available about the thermodynamic evaluation for biomass gasification process using updraft gasifier. Therefore, to minimize errors, the gasification of dry refinery sludge (DRS) is carried out in adiabatic system at atmospheric pressure under ambient air conditions. The objectives of this paper are to investigate the physical and chemical energy and exergy of product gas...

Organic and inorganic contaminants in sewage sludge may cause their presence also in the by-products formed during gasification processes. Thus, this paper presents multidirectional chemical instrumental activation analyses of dried sewage sludge as well as both solid (ash, char coal) and liquid (tar) by-products formed during sewage gasification in a fixed bed reactor which was carried out to ...

The objective of this study was to develop a supported tri-metallic catalyst (nano-Ni-La-Fe/γ-Al2O3) for tar removal in biomass steam gasification, to significantly enhance the quality of the produced gas. For this purpose, the supported tri-metallic catalysts were prepared by a deposition-precipitation (DP) method. Different analytical approaches were used to characterize the synthesized catal...

Bio-oil, a mixture of complex oxygenated hydrocarbons, is obtained through fast pyrolysis of solid biomass. As biomass is low in energy density and not easily transportable, a novel approach is to convert biomass to bio-oil, transport bio-oil to a centralized facility, gasify bio-oil to syngas, and upgrade syngas to transportation fuels and other high-value chemicals. In this study, a comprehen...

The reaction kinetics of gasification are important for the design of gasifiers using biomass feedstocks, such as lignin, produced in biorefinery processes. Condensed and uncondensed lignin samples used in the present study were prepared using the SEW (SO2-ethanolwater) fractionation process applied to spruce wood chips: the dissolved lignin is precipitated during the recovery of SO2 and ethano...