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    Exergetic efficiency of synthetic natural gas (SNG) production from biomass
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    Synthetic natural gas (SNG) is suggested as an important future energy carrier. The conventional route for SNG production is based on gasification of biomass to synthetic gas and the subsequent methanation of synthetic gas to SNG. This study is aimed to analyze the process units using the concept of exergy. Exergy analysis is a promising method, based on the 2nd law of thermodynamics, to analyze and improve chemical processes. In this work a detailed exergy analysis is performed for the SNG process based on woody biomass gasification. The main elements of the system are gasifier, gas cleaning, synthetic gas compression, methanation and final SNG condition. The above-mentioned process was simulated with a computer model using the flow-sheeting program Aspen Plus. Optimal values of the process conditions, particularly for the methanation reactors, are found. The internal exergy losses of different system units are evaluated. The largest internal exergy losses take place in the gasifier, methanation section and CO2 capture unit. The highest overall exergetic efficiency of 72.6% was found applying the following operating conditions: gasifier 700 °C and 1 bar; 1st methanation reactor 580 °C and 2nd methanation reactor 405 °C.
    Methanation
    Substitute natural gas
    Wood gas generator
    Exergy efficiency
    Citations (36)
    The production of synthetic natural gas from biomass(Bio-SNG) by gasification is an attractive option to reduce CO2 emissions and replace declining fossil natural gas reserves.Bio-SNG via gasification,cleaning,conditioning,methanation of the synthesis gas,and subsequent upgrading can be regarded as a ‘second generation’ renewable energy technology.According to the comprehensive analysis on synthetic technique of Bio-SNG,the process flowsheet abroad are analyzed and compared.Some suggestions are provided on development and applications of Bio-SNG technologies.
    Substitute natural gas
    Methanation
    Renewable natural gas
    Producer gas
    Synthetic fuel
    Citations (5)
    The gasification of biomass can be coupled to a downstream methanation process that produces synthetic natural gas (SNG). This enables the distribution of bioenergy in the existing natural gas grid. A process model is developed for the small-scale production of SNG with the use of the software package Aspen Plus (Aspen Technology, Inc., Burlington, MA, USA). The gasification is based on an indirect gasifier with a thermal input of 500 kW. The gasification system consists of a fluidized bed reformer and a fluidized bed combustor that are interconnected via heat pipes. The subsequent methanation is modeled by a fluidized bed reactor. Different stages of process integration between the endothermic gasification and exothermic combustion and methanation are considered. With increasing process integration, the conversion efficiency from biomass to SNG increases. A conversion efficiency from biomass to SNG of 73.9% on a lower heating value basis is feasible with the best integrated system. The SNG produced in the simulation meets the quality requirements for injection into the natural gas grid. Copyright © 2012 John Wiley & Sons, Ltd.
    Substitute natural gas
    Methanation
    Wood gas generator
    Heat of combustion
    Producer gas
    Citations (51)