Species – Transport CFD model for the gasification of rice husk ( Oryza Sativa ) using downdraft gasifier

Chockalingam, Murugan Paradesi; Sekhar, S. Joseph

doi:10.1016/j.compag.2017.05.004

Cited by 62 publications

(16 citation statements)

References 26 publications

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“…Rice husk feedstock was gathered from local rice mill was ovendried at 83 o C overnight before grinding. The proximate analysis, elemental analysis and LHV of rice husk are shown in after pulverizing and sieving, the particle diameter of rice husk is less than 200mm [16][17][18]. The RH was sun-dried for a period of 35-49 h before it was pulverized to 250-1000 μm different particle sizes.…”

Section: Methodsmentioning

confidence: 99%

Optimized Production of Syngas from Rice Hush Using Steam Explosion in Dual Fluidized Bed Gasifier

Ahmad¹,

Ahmad²,

Asghar³

et al. 2021

AustinChemEng

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Converting rice husk into energy is a promising method of generating renewable energy and reducing greenhouse gas emissions. In this research rice hush is considered as biomass fuel. The characteristics of rice husk gasification were investigated at an Equivalence Ratio (ER) of 0.25–0.38 and a gasifier temperature of 750-870°C in 20 tons per day (TPD) using steam explosion process in fluidized bed gasifier system. Different operation conditions, temperatures and loads, are investigated for their effects on the compositions, calorific properties, gasification efficiencies of syngas. The effects of the critical parameters, namely, Steam-to-Biomass Ratio (S/B), Particle size variation and gasification temperature on the quality of the product gas as well as the gasifier cold gas efficiency were analyzed. This is the new finding in the research. The optimal conditions of the gasification operation were an ER of 0.20 and gasifier temperature of 800°C. The low heating value of the gas product and cold gas efficiency were 1390kcal/Nm³ and 75%, respectively. After passing the generated gas through the gas cleaning units, it was confirmed that the tar in the product gas was removed with an efficiency of 98%. The cleaned product gas was used for the operation of 420kW, gas engine. Pressure loss often occurred at the bottom of the gasifier during the gasification operation; we found that the agglomerates generated by the gasification process caused it. To prevent the pressure loss caused by the agglomerates, the stable control of temperature inside the gasifier is needed and an ash removal device remove agglomerates should be installed to maintain stable long-term operation. This paper leads towards the production of Syngas and further on the electricity from the rice husk, an eminent biomass, copiously available all around the world. Especially in Pakistan, the rice is used abundantly so the raw material is easily available. The gas is produced using the gasification process in dual fluidized gasifier. It is a wonderful alternative to the natural gas with high calorific value. The sulfur contents are quite less compared to natural gas. It also have a good correlation with environment as flue gases emission is negligible relative to other source like coal, wood, plastic, waste etc. Another benefit of this process is the waste management and pollution control. The results are developed by using the detailed analysis of the process values of plants which is generating electricity by rice husk gasification. We learned, all results revealed that the dual fluidized bed gasification is more economical and efficient method compared to all other methods for commercial scale production of syngas. Results are analyzed which imply that the biomass is more gigantic source which replace the fossil fuels and leads towards the green energy in a more economical way. This paper provides an overview of previous works on combustion and gasification of rice husk in atmospheric fluiuidized bed reactors and summarizes the state of the art knowledge. As the high ash content, low bulk density, p characteristics and low ash melting point makes the other types of reactors like grate furnaces and downdraft gasifers either inefficient or unsuitable for rice husk conversion to energy, the fluiuidized bed reactor seems to be the promising choice. The overview shows that the reported results are from only small bench or lab scale units. Although a combustion efficiency of about 80% can normally be attained; the reported values in the literature, which are more than 95%, seem to be in higher order. Combustion intensity of about 530kg/h/m² is reported. It is also technically feasible to gasify rice husk in a fluidized bed reactor to yield combustible producer gas, even with sufficient heating value for application in internal combustion engines.

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Section: Methodsmentioning

confidence: 99%

Optimized Production of Syngas from Rice Hush Using Steam Explosion in Dual Fluidized Bed Gasifier

Ahmad¹,

Ahmad²,

Asghar³

et al. 2021

AustinChemEng

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“…The experiment indicated that the wood pellet consumption rate during steady state was 1.750 ± 0.048 g/s or approximately 6.3 kg/h. With a similar ER (0.2-0.3), the fuel consumption of wood pellets was significantly lower than that of rice husks (18.612-23.875 kg/h) due to the better fuel quality of the wood pellets (low ash content) (Murugan and Sekhar 2017). Validation of fuel consumption is the foundation for other parameter modeling.…”

Section: Fuel Consumption During the Gasification Processmentioning

confidence: 98%

“…CFD using the Euler-Lagrange approach for dispersed two-phase flows was utilized for 10 kg/h downdraft gasifier modeling; the simulation and experiment found that the air flow rate affected the temperature profile along the height of the gasifier as well as the concentration of the composition of the syngas outlet (Meenaroch et al 2015). Simulation of a 40-kW downdraft gasifier using rice husks as fuel was performed by Murugan and Sekhar (2017). Results predicted that the equivalence ratio (ER) of the gasification process of 0.30 gave maximum syngas heating value of 5.19 MJ/N m 3the syngas composition was 22% CO, 13% H 2 , 8% CO 2 , and 1.7% CH 4 .…”

Section: Introductionmentioning

confidence: 99%

Two-dimensional CFD simulation and pilot-scale experimental verification of a downdraft gasifier: effect of reactor aspect ratios on temperature and syngas composition during gasification

Siripaiboon

Sarabhorn

Areeprasert

2020

Int J Coal Sci Technol

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This paper focuses on a two-dimensional CFD simulation of a downdraft gasifier and a pilot-scale experiment for verification using wood pellet fuel. The simulation work was carried out via the ANSYS-Fluent CFD software package with in-house coding via User Defined Function. Three gasification parameters were taken into account in the simulation and validation to achieve highly accurate results; namely, fuel consumption, temperature profile, and syngas composition. After verification of the developed model, the effects of aspect ratios on temperature and syngas composition were investigated. Results from simulation and experimental work indicated that the fuel consumption rate during the steady state gasification experiment was 1.750 ± 0.048 g/s. The average steady state temperature of the experiment was 1240.32 ± 14.20 K. In sum, the fuel consumption and temperature profile during gasification from modeling and experimentation show an error lower than 1.3%. Concentrations of CO, CO2, H2, and CH4 were 20.42 vol%, 15.09 vol%, 8.02 vol%, and 2.6 vol%, respectively, which are comparable to those of the experiment: 20.00 vol%, 15.48 vol%, 8.00 vol%, and 2.65 vol%. A high concentration of syngas is observed in the outer radial part of the reactor because of the resistive flow of the air inlet and the synthesis gas produced. The average temperatures during the steady state of the gasifier with aspect ratios (H/D) of 1.00, 1.38 (experiment), and 1.82 were 978.77 ± 11.60, 1256.46 ± 9.90, and 1368.94 ± 9.20 K, respectively. The 1.82 aspect ratio reactor has the smallest diameter, therefore the radiative heat transferred from the reactor wall affects the temperature in the reactor. Syngas compositions are comparable. Inverse relationships between the aspect ratios and the syngas LHV, (4.29–4.49 MJ/N m3), cold gas efficiency (29.66% to 31.00%), and carbon conversion (79.59% to 80.87%) are observed.

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“…The goals of the study are: (i) to give the continuous advancement in the domain of laboratory and analytical characters connected by steam gasification; and (ii) to deliver the existing situation of the investigation in this area of steam gasification of several biomasses including the current study holes. The principal fields comprised in the survey involve gasification; steam gasification; experimental studies on steam gasification using various types of gasifiers and comparison of operating conditions (Murugan & Joseph Sekhar, 2017). The outline of this review article can be summarized as follows:…”

Section: Introductionmentioning

confidence: 99%

Energy production from steam gasification processes and parameters that contemplate in biomass gasifier – A review

Siwal

Zhang

Sun

et al. 2020

Bioresource Technology

115

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The transformation of biomass using steam gasification is a chemical route to facilitate changes in organic or residue supported carbonaceous substances addicted to carbon mono-oxide, hydrogen including carbon-dioxide , etc. However, to commercialize the method of steam gasification, the hurdles persist during the gasification as well as downstream processing. This article delivers a summary of the different approaches that are described in the previous studies to achieve H2 refinement and adaptation within the gasifier system. These include advanced aspects in the research and development of biomass gasification (alike advancements under the gasification operation). The upshot of diverse operating conditions like steam flow rate, operating temperature, moisture content, gasifier agents, residence time, biomass to air, steam to biomass, equivalence ratio, etc. towards the execution of biomass gasifier. This review accomplishes that the interdependence of several issues must be considered in point to optimise the producer gas.

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Species – Transport CFD model for the gasification of rice husk ( Oryza Sativa ) using downdraft gasifier

Cited by 62 publications

References 26 publications

Optimized Production of Syngas from Rice Hush Using Steam Explosion in Dual Fluidized Bed Gasifier

Optimized Production of Syngas from Rice Hush Using Steam Explosion in Dual Fluidized Bed Gasifier

Two-dimensional CFD simulation and pilot-scale experimental verification of a downdraft gasifier: effect of reactor aspect ratios on temperature and syngas composition during gasification

Energy production from steam gasification processes and parameters that contemplate in biomass gasifier – A review

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