Development of a high‐temperature two‐stage entrained flow gasifier model for the process of biomass gasification and syngas formation

Summary A comprehensive model is developed to predict and optimize the hydrogen production via integrated configuration of steam gasification process of biomass and water‐gas shift reaction by taking advantage of the ASPEN plus software and sensitivity analysis techniques. The steam gasification process of three different generations of biomass, including corn cob as the first generation, wood residue and rice husk as second generation, and Spirulina algae as the third, are investigated and evaluated to achieve maximum hydrogen production. This model is successfully validated with experimental data reported in the literature about steam gasification of rice husk in the fluidized bed reactor. The impact of main operating parameters is considered in terms of products composition, hydrogen yield, CO conversion, H2/CO ratio in the gas products stream, and cold gas efficiency (CGE). The results indicated that the maximum hydrogen concentration is achieved at the highest steam to biomass (S/B) ratio in the gasifier and water‐gas shift (WGS) reactor and at the lowest WGS reaction temperature, whereas there is an optimum value about the gasification temperature. The highest CO conversion and H2/CO molar ratio belong to rice husk biomass at all considered range of temperature, whereas they are almost the same for wood residue and Spirulina. The predicted results confirmed that CGE of all feedstocks improves with increasing gasification temperatures and S/B ratio. The steam gasification performance of different feedstocks at 750°C is ranked as wood residue (83.56%) > spirulina (83.47%) > corn cob (74.94%) > rice husk (69.86%). The presented configuration can be applied as a novel approach for process evaluation and optimization through the downdraft biomass gasification integrated with water‐gas shift reaction to intensify the hydrogen production.

Section: Introductionmentioning

confidence: 99%

Hydrogen production via integrated configuration of steam gasification process of biomass and water‐gas shift reaction: Process simulation and optimization

Babatabar

Saidi

2021

“…The global energy demand is increasing rapidly and will continue to grow in the foreseeable future 1 . Currently, fossil fuels supply about 80% of the world energy demand, 2 out of which nearly 30% of total energy and 40% of electricity is generated from coal 3,4 .…”

Section: Introductionmentioning

confidence: 99%

Effect of reactant types (steam, CO ₂ and steam + CO ₂ ) on the gasification performance of coal using entrained flow gasifier

Shahabuddin

Bhattacharya

2021

This study investigates the gasification behaviour of bituminous coal using different reactants of CO 2 , steam and a mixture of CO 2 and steam under entrained flow gasification conditions at temperatures of 1000 C and 1200 C with atmospheric pressure. The major gas constituents of the syngas were measured using online micro-GC with a model number Varian 490, whereas the minor pollutant gases were analysed using Kitagawa gas detection tubes. A maximum carbon conversion of 86% was achieved under steam gasification at a temperature of 1200 C compared to 74% from CO 2 gasification. The higher carbon conversion from steam gasification is due to the higher gasification reactivity than CO 2 gasification. At 1000 C, the lower heating value (LHV) from steam gasification was determined to be 60%, 70% and 80% higher than that of CO 2 gasification using the reactant concentrations of 10, 20 and 40 vol. %, respectively. Using a stoichiometric 50/50 ratio of CO 2 and steam, the yield of H 2 , CO and CH 4 were increased by 56%, 106% and 35% compared to that of pure CO 2 gasification. At 1000 C, the LHV under mixed reactant condition is close to the LHV from the pure steam gasification at 1200 C. In steam gasification, increasing the temperature by 200 C from 1000 C decreases the LHV by 17 and 10% using 10 and 20 vol.% steam. The higher heating value from steam gasification is due to the H 2 and CH 4 -rich syngas compared to CO-rich syngas in CO 2 gasification. The BET surface area of the solid char from steam gasification is about 17 and two times higher than that of CO 2 gasification at 1000 C and 1200 C, respectively.

“…1 In various biomass conversion technologies, gasification is a process in which gasification agents are introduced under high-temperature conditions to conduct thermochemical reactions to convert solid fuels into high-energy synthesis gas (syngas) and attracted special attention in the current energy demands. 2 Hydrogen-rich synthesis gas can be produced and then through FT (Fischer-Tropsch) synthesis into value-added chemicals. 3 At the same time, it has a high conversion efficiency, so it is considered to be the most promising way of biomass conversion.…”

Section: Introductionmentioning

confidence: 99%

“…Biomass energy is a potential substitute for fossil fuels in the future energy system, which can meet the daily energy demand as a promising renewable energy and forward a country toward sustainable and prosperous future 1 . In various biomass conversion technologies, gasification is a process in which gasification agents are introduced under high‐temperature conditions to conduct thermochemical reactions to convert solid fuels into high‐energy synthesis gas (syngas) and attracted special attention in the current energy demands 2 . Hydrogen‐rich synthesis gas can be produced and then through FT (Fischer‐Tropsch) synthesis into value‐added chemicals 3 .…”

Section: Introductionmentioning

confidence: 99%

Study on the steam gasification reaction of biomass char under the synergistic effect of Ca‐Fe : Analysis of kinetic characteristics

Pang

Chen

et al. 2021

Biomass char gasification is an important part of biomass conversion technology; the addition of additives can effectively change the gasification reaction rate of char. The kinetic characteristics of steam gasification reaction of biomass char particles were explored by adding CaO, Fe 2 O 3 , and CaFe mixed catalyst to biomass, and the apparent activation energy and pre-exponential factors of char particles were obtained. Experimental results show that the kinetic reaction process of char steam gasification follows the shrinking cylinder model. Through linear fitting, it can be obtained that there is a good linear correlation between activation energy and pre-exponential factor, which follows the dynamic compensation effect. Under the same temperature conditions, CaO can accelerate the reaction rate of char, while Fe 2 O 3 can delay the gasification rate of char particles because of sintering phenomenon at high temperature. The synergistic effect of CaFe can reduce the total activation energy of the reaction. The addition of CaO can greatly change the kinetic performance of the Fe 2 O 3 catalyst, inhibit the sintering deactivation reaction of Fe 2 O 3 at high temperature, increase the diffusion path of steam, and promote the char steam gasification reaction.