Coal and Biomass Gasification

Numerous reviews have been found related to individual studies on coal gasification (CG) and biomass gasification (BG). However, this review deals mainly with the CO-gasification (COG) of numerous types of coal and biomass and then compares their results with those obtained using coal and biomass gasification in detail. There are several process parameters which have a direct effect on the gasification process and among them temperature is the most significant one. In this paper, the production of H 2 , CO 2 , CO, CH 4 , and other hydrocarbons in CG, BG and COG with the variation of temperature is reviewed in detail. As it mainly influences the gaseous products and their characteristic behaviour, this review takes into account the effect of temperature on various other parameters such as carbon conversion, gas yield, calorific value, cold gas efficiency as well as tar and char contents in various kinds of coals, biomasses and their mixtures under catalytic or non-catalytic conditions.

In this study, a coal gasification model is developed based on nine simultaneous reactions. For given gasification temperature and pressure, the air/fuel and water vapor/fuel ratio are optimized for maximum H2/CO ratio by parametric study. Furthermore, the cold gas efficiency and higher heating value of the synthesis gas produced are computed for each case. Optimum locations of investigated parameters are also searched for maximizing cold gas efficiency and higher heating value of the synthesis gas.

El presente trabajo evalúa la factibilidad de fabricar sistemas de gasificación en Colombia, partiendo del análisis detallado de la cadena de suministro de estos equipos. Como metodología se utiliza una herramienta de diseño en ingeniería complementada con un análisis multicriterio para seleccionar el tipo de tecnología. De igual forma se hacen proyecciones de costos por economías de escala y de aprendizaje, partiendo de experiencias resultantes de varios proyectos de investigación desarrollados en tres universidades colombianas.

Trigeneration or Combined Cooling, Heat and Power (CCHP) which is based upon combined heat and power (CHP) systems coupled to an absorption chiller can be recognized as one of the best technologies recovering biomass effectively to heat, cooling and power. Co-gasification of the lignite and biomass can provide the possibility for safe and effective disposal of different waste types as well as for sustainable and environmentally-friendly production of energy. In this article, a trigeneration system based on an IC engine and gasifier reactor has been simulated and realized using Thermoflex simulation software. Performance results suggest that utilization of sustainably-grown biomass in a Tri-Generation Power Plant (TGPP) can be a possibility for providing cooling, heat and power demands with local renewable sources and reducing the environmental impacts of the energy conversion systems.

Numerous reviews have been found related to individual studies on coal gasification (CG) and biomass gasification (BG). However, this review deals mainly with the CO-gasification (COG) of numerous types of coal and biomass and then compares their results with those obtained using coal and biomass gasification in detail. There are several process parameters which have a direct effect on the gasification process and among them temperature is the most significant one. In this paper, the production of H 2 , CO 2 , CO, CH 4 , and other hydrocarbons in CG, BG and COG with the variation of temperature is reviewed in detail. As it mainly influences the gaseous products and their characteristic behaviour, this review takes into account the effect of temperature on various other parameters such as carbon conversion, gas yield, calorific value, cold gas efficiency as well as tar and char contents in various kinds of coals, biomasses and their mixtures under catalytic or non-catalytic conditions.

Tars released by the gasification of sewage sludge in a spouted bed gasifier have been collected, quantified and characterised. The amounts collected were low which shows that the volatiles contained in the feedstock were cracked efficiently under the conditions in the gasifier. The presence of a high concentration of steam in the gasifying medium enhanced the conversion further. Within the 760–980 8C range, the amount present did not show any variation with temperature of formation. GC/MS of a limited number of samples showed that the tars it had
an aromatic character, as expected at the temperatures used. Approximately, 60–70% of the tars evaporated below 450 C.
Thermogravimetric analysis of the tar-trap samples has allowed an estimation of the boiling point distributions of the samples. For the majority of the tar samples, from both types of sewage, between 60 and 70% of the tar boiled at,450 C. The Biogran tar exhibited a trend of an increase in the 250 C fraction and an increase in the 450 C fraction, with increasing temperature of formation. The Danish tar-trap samples showed a decreasing trend in both fractions with increasing temperature. These data give an indication of the way the tars progressively break down under the gasifier conditions and infers that steam can have an impact on the reaction pathway. Changes in the composition of the tars with temperature were also identified using size exclusion chromatography (SEC) and by ultra violet fluorescence spectroscopy (UV-F). SEC showed that the molecular sizes of lighter material (retained peak in the chromatogram) decreased with increasing temperature, whereas that of the heavier material (excluded peak) generally increased. The large area of the retained peaks compared with the excluded peaks showed that lower mass material formed the majority of the tar samples. The mass-averaged molecular weights of the retained material showed a trend of decreasing values with increased gasifier temperature. The UV-F spectra of samples indicated the presence of higher concentrations of larger polynuclear aromatic ring systems, heterocyclic structures and alkyl or heteroatom substitutents as the
temperature of formation increased.

Trigeneration or Combined Cooling, Heat and Power (CCHP) which is based upon combined heat and power (CHP) systems coupled to an absorption chiller can be recognized as one of the best technologies recovering biomass effectively to heat, cooling and power. Co-gasification of the lignite and biomass can provide the possibility for safe and effective disposal of different waste types as well as for sustainable and environmentally-friendly production of energy. In this article, a trigeneration system based on an IC engine and gasifier reactor has been simulated and realized using Thermoflex simulation software. Performance results suggest that utilization of sustainably-grown biomass in a Tri-Generation Power Plant (TGPP) can be a possibility for providing cooling, heat and power demands with local renewable sources and reducing the environmental impacts of the energy conversion systems.

Numerous reviews have been found related to individual studies on coal gasification (CG) and biomass gasification (BG). However, this review deals mainly with the CO-gasification (COG) of numerous types of coal and biomass and then compares their results with those obtained using coal and biomass gasification in detail. There are several process parameters which have a direct effect on the gasification process and among them temperature is the most significant one. In this paper, the production of H 2, CO 2, CO, CH 4, and other hydrocarbons in CG, BG and COG with the variation of temperature is reviewed in detail. As it mainly influences the gaseous products and their characteristic behaviour, this review takes into account the effect of temperature on various other parameters such as carbon conversion, gas yield, calorific value, cold gas efficiency as well as tar and char contents in various kinds of coals, biomasses and their mixtures under catalytic or non-catalytic conditions. © 2012 Elsevier Ltd.

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