scholarly journals Co-Gasification Characteristics of Coal and Biomass Using CO2 Reactant under Thermodynamic Equilibrium Modelling

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7384
Author(s):  
M. Shahabuddin ◽  
Sankar Bhattacharya
Keyword(s):  
Steady State ◽  
Thermodynamic Equilibrium ◽  
Operating Conditions ◽  
Heating Value ◽  
Entrained Flow ◽  
Cold Gas Efficiency ◽  
Lower Heating Value ◽  
Entrained Flow Gasifier ◽  
Gas Efficiency ◽  
Increasing Temperature

This study assessed the entrained flow co-gasification characteristics of coal and biomass using thermodynamic equilibrium modelling. The model was validated against entrained flow gasifier data published in the literature. The gasification performance was evaluated under different operating conditions, such as equivalence ratio, temperature, pressure and coal to biomass ratio. It is observed that the lower heating value (LHV) and cold gas efficiency (CGE) increase with increasing temperature until the process reaches a steady state. The effect of pressure on syngas composition is dominant only at non-steady state conditions (<1100 °C). The variation in syngas composition is minor up to the blending of 50% biomass (PB50). However, the PB50 shows a higher LHV and CGE than pure coal by 12%and 18%, respectively. Overall, biomass blending of up to 50% favours gasification performance with an LHV of 12 MJ/kg and a CGE of 78%.

scholarly journals Simulation of Cotton Stalks for Syngas Generation Using CO2 and Air as Gasifying Agents

2020 ◽  
Vol 39 (2) ◽  
pp. 371-379
Author(s):  
Ghulamullah Maitlo ◽  
Rasool Bux Mahar ◽  
Khan Mohammad Brohi
Keyword(s):  
Biomass Gasification ◽  
Cotton Stalk ◽  
Heating Value ◽  
Entrained Flow ◽  
Cold Gas Efficiency ◽  
Cotton Stalks ◽  
Lower Heating Value ◽  
Entrained Flow Gasifier ◽  
Gas Efficiency ◽  
Lower Heating

Gasification of coal and biomass using CO2 and air mixture as a carrier gas offers an encouraging way to eliminate the shortage of energy and reduce carbon dioxide emissions. In the present study, the EulerianLagrangian approach was applied to understand the thermochemical conversion behavior of feedstock in entrained flow gasifier. Commercial CFD (Computational Fluid Dynamics) code ANSYS FLUENT®14 was used for the simulation purpose. It was observed that with variation in the CO2 in the air and the CO2 to cotton stalk ratio had a meaningful effect on gasification performance. The different ratios of air and CO2 in varying percentages such as 20% CO2, 30% CO2, 40% CO2, 50% CO2, 60% CO2, 70% CO2 and remaining percentages of air were introduced in entrained flow gasifier. With the increase in CO2 to cotton stalk ratio, the concentration of H2 and CO2 decreased whereas as the concentration of CO improved. It is revealed that mole fraction of CO and CH4 attained maximum when CO2% in the air was 50% and H2 mole fraction was observed maximum at a CO2% in the air was 30%. At 50% CO2 mixture in air, the maximum lower heating value and cold gas efficiency were observed. Therefore, the optimum situation might be 50% percentage CO2 in the gasifying agent for this entrained flow gasifier. Hence an increase in CO and H2, the cold gas efficiency and lower heating value reached the maximum. However, this study provides an appropriate route for energy production using cotton stalks as raw material and will help in designing and operation of the entrained flow reactor. The simulations indicate the thermodynamic limits of gasification and allow for the formulation of the general principles ruling this process. Moreover, no literature is available for the parametric investigations of Pakistani biomass gasification using entrained-flow gasifier. So this is a novel work for Pakistan and will be treated as foundation work for biomass gasification in the country.

scholarly journals Investigation of the Coal Gasification Process Under Various Operating Conditions Inside a Two-Stage Entrained Flow Gasifier

2012 ◽  
Vol 4 (2) ◽  
Author(s):  
Armin Silaen ◽  
Ting Wang
Keyword(s):  
Coal Gasification ◽  
Operating Conditions ◽  
Coal Slurry ◽  
Two Stage ◽  
Heating Value ◽  
Fuel Distribution ◽  
Entrained Flow ◽  
One Stage ◽  
Gasification Process ◽  
Entrained Flow Gasifier

Numerical simulations of the coal gasification process inside a generic 2-stage entrained-flow gasifier fed with Indonesian coal at approximately 2000 metric ton/day are carried out. The 3D Navier–Stokes equations and eight species transport equations are solved with three heterogeneous global reactions, three homogeneous reactions, and two-step thermal cracking equation of volatiles. The chemical percolation devolatilization (CPD) model is used for the devolatilization process. This study is conducted to investigate the effects of different operation parameters on the gasification process including coal mixture (dry versus slurry), oxidant (oxygen-blown versus air-blown), and different coal distribution between two stages. In the two-stage coal-slurry feed operation, the dominant reactions are intense char combustion in the first stage and enhanced gasification reactions in the second stage. The gas temperature in the first stage for the dry-fed case is about 800 K higher than the slurry-fed case. This calls for attention of additional refractory maintenance in the dry-fed case. One-stage operation yields higher H2, CO and CH4 combined than if a two-stage operation is used, but with a lower syngas heating value. The higher heating value (HHV) of syngas for the one-stage operation is 7.68 MJ/kg, compared with 8.24 MJ/kg for two-stage operation with 75%–25% fuel distribution and 9.03 MJ/kg for two-stage operation with 50%–50% fuel distribution. Carbon conversion efficiency of the air-blown case is 77.3%, which is much lower than that of the oxygen-blown case (99.4%). The syngas heating value for the air-blown case is 4.40 MJ/kg, which is almost half of the heating value of the oxygen-blown case (8.24 MJ/kg).

The Effect of Biomass Contents with Heavy Metal on Gasification Efficiency during Fluidized Bed Gasification Process

2012 ◽  
Vol 512-515 ◽  
pp. 575-578
Author(s):  
Hsien Chen ◽  
Chiou Liang Lin ◽  
Wun Yue Zeng ◽  
Zi Bin Xu
Keyword(s):  
H2 Production ◽  
Heating Value ◽  
Gasification Process ◽  
Cold Gas Efficiency ◽  
Zn Concentration ◽  
Lower Heating Value ◽  
Gasification Efficiency ◽  
Waste Gasification ◽  
Gas Efficiency ◽  
Cu And Zn

Catalysis was used to increase the H2 production, syngas heating value, enhanced carbon conversion efficiency and cold gas efficiency during gasification. Due to Cu and Zn were abundant in waste according to previous researches, this research discussed the effect of Cu and Zn on artificial waste gasification. The syngas composition and total lower heating value (LHV) were determined in this study. The results showed that the existence of Cu and Zn increased production of H2 and CO. However, the production of CH4 and CO2 decreased. At same time, total LHV was also increased. Additionally, the different Cu concentration affected gas composition and LHV, but the effect of Zn concentration was not significant.

scholarly journals Co-Gasification of Treated Solid Recovered Fuel Residue by Using Minerals Bed and Biomass Waste Blends

Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 2081
Author(s):  
Md Tanvir Alam ◽  
Se-Won Park ◽  
Sang-Yeop Lee ◽  
Yean-Ouk Jeong ◽  
Anthony De Girolamo ◽  
...  
Keyword(s):  
Low Cost ◽  
Biomass Waste ◽  
Heating Value ◽  
Pine Sawdust ◽  
Syngas Production ◽  
Cold Gas Efficiency ◽  
Natural Minerals ◽  
Lower Heating Value ◽  
Gas Efficiency ◽  
Bed Material

Solid recovered fuel (SRF) residue, which is leftovers from the SRF manufacturing process, usually is discarded in landfill because of its low heating value and high ash and moisture content. However, it could be used as a fuel after mechanical and biological treatment. Gasification experiments were conducted on treated SRF residue (TSRFR) to assess the viability of syngas production. Efforts were also made to improve the gasification performance by adding low-cost natural minerals such as dolomite and lime as bed material, and by blending with biomass waste. In the case of additive mineral tests, dolomite showed better performance compared to lime, and in the case of biomass blends, a 25 wt% pine sawdust blend with TSRFR showed the best performance. Finally, as an appropriate condition, a combined experiment was conducted at an equivalence ratio (ER) of 0.2 using a 25 wt% pine sawdust blend with TSRFR as a feedstock and dolomite as the bed material. The highest dry gas yield (1.81 Nm3/kg), with the highest amount of syngas (56.72 vol%) and highest lower heating value (9.55 MJ/Nm3) was obtained in this condition. Furthermore, the highest cold gas efficiency (48.64%) and carbon conversion rate (98.87%), and the lowest residue yield (11.56%), tar (0.95 g/Nm3), and gas pollutants content was observed.

Gasification of Empty Fruit Bunch Briquettes in a Fixed Bed Tubular Reactor for Hydrogen Production

2014 ◽  
Vol 699 ◽  
pp. 534-539 ◽  
Author(s):  
Bemgba Bevan Nyakuma ◽  
Mojtaba Mazangi ◽  
Tuan Amran Tuan Abdullah ◽  
Anwar Johari ◽  
Arshad Ahmad ◽  
...  
Keyword(s):  
Fixed Bed ◽  
Tubular Reactor ◽  
Producer Gas ◽  
Gas Composition ◽  
Carbon Conversion ◽  
Heating Value ◽  
Cold Gas Efficiency ◽  
Effects Of Temperature ◽  
Gas Efficiency ◽  
Increasing Temperature

The gasification of EFB briquette was investigated in a fixed bed tubular reactor to examine the effects of temperature on gas composition, heating value and cold conversion efficiency.The resultsrevealedthat H2 gas composition increased from 17.17 mol. % to 29.67 mol. % with increasing temperature from 600°C to 700°C at an equivalence ratio (ER) of 0.4. The heating value (HHV) of the producer gas increased from 6.18 MJ/Nm3 to 7.64 MJ/Nm3 and cold gas efficiency increased from 35.19% to 43.50% with increasing temperature during gasification. However, carbon conversion efficiency increased only marginally from 31.85% to 32.84% while a significant quantity of char (~ 21%) was produced per unit mass of EFB briquette. The results indicate that higher temperatures are required to increase the overall efficiency of EFB briquette gasification in a fixed bed tubular reactor.

Syngas Generation From Landfills Derived Torrefied Refuse Fuel Using a Downdraft Gasifier

2020 ◽  
Vol 143 (5) ◽  
Author(s):  
Krongkaew Laohalidanond ◽  
Somrat Kerdsuwan ◽  
Kiran Raj Goud Burra ◽  
Jinhu Li ◽  
Ashwani K. Gupta
Keyword(s):  
Hydrocarbon Fuel ◽  
High Energy ◽  
High Energy Density ◽  
Heating Value ◽  
Downdraft Gasifier ◽  
Cold Gas Efficiency ◽  
Lower Heating Value ◽  
Gas Efficiency ◽  
Lower Heating ◽  
Cold Gas

Abstract Landfill reclamation is a good solution to utilize the wasted land occupied by municipal solid waste dumpsites or landfill sites. This also offers a good means to recover valuable materials and form environmentally benign green refuse-derived fuel (RDF) for use in power production. However, due to the heterogenous composition of the wastes, it is crucial to homogenize and upgrade the waste hydrocarbon fuel properties. Torrefaction is a thermochemical process that utilizes low temperature and inert environment to drive off the moisture and volatile fractions present in wastes to form valuable fuel. This upgraded RDF from reclaimed landfills offer high energy density and favorable hydrophobicity for use as a fuel feedstock in gasification to produce syngas for power generation. The objectives of this study are to first upgrading the reclaimed landfill wastes to RDF using torrefaction followed by its conversion to form clean syngas in a downdraft gasifier. This study examines the effect of air ratio on syngas heating value and cold gas efficiency. A comparison is made on the syngas produced from gasification using reclaimed landfill wastes and torrefied RDF. Experiments were conducted using a 10 kg/h lab-scale downdraft gasifier. The air ratios examined were 0.22, 0.27, and 0.32. The results showed an optimum air ratio of 0.27 operated with a gasifier using torrefied RDF. The results showed improved syngas quality, in terms of syngas composition, lower heating value, and cold gas efficiency. The lower heating value of 4.22 MJ/Nm3 and the cold gas efficiency of 65.84% were achieved. The results showed that landfill mining can provide ultimate solution to get rid of dumped wastes from landfills using torrefaction for high-quality fuel followed by the recovery of green and clean syngas energy using gasification.

Biodiesel Effects on Influencing Parameters of Brake Fuel Conversion Efficiency in a Medium Duty Diesel Engine

2010 ◽  
Vol 132 (12) ◽  
Author(s):  
Joshua A. Bittle ◽  
Jesse K. Younger ◽  
Timothy J. Jacobs
Keyword(s):  
Conversion Efficiency ◽  
Energy Content ◽  
Combustion Efficiency ◽  
Operating Conditions ◽  
Biodiesel Fuel ◽  
Mass Energy ◽  
Fuel Conversion ◽  
Heating Value ◽  
Lower Heating Value ◽  
Lower Heating

Biodiesel remains an alternative fuel of interest for use in diesel engines. A common characteristic of biodiesel, relative to petroleum diesel, is a lowered heating value (or per mass energy content of the fuel). For same torque engine comparisons, the lower heating value translates into a higher brake specific fuel consumption (amount of fuel consumed per unit of power produced). The efficiency at which fuel energy converts into work energy, however, may remain unchanged. In this experimental study, evaluating nine unique engine operating conditions, the brake fuel conversion efficiency (an assessor of fuel energy to work energy efficiency) remains unchanged between 100% petroleum diesel fuel and 100% biodiesel fuel (palm olein) at all conditions, except for high load conditions. Several parameters may affect the brake fuel conversion efficiency, including heat loss, mixture properties, pumping work, friction, combustion efficiency, and combustion timing. This article describes a study that evaluates how the aforementioned parameters may change with the use of biodiesel and petroleum diesel, and how these parameters may result in differences in the brake fuel conversion efficiency.

Effect of Swirl on Gasification Characteristics in an Entrained-flow Coal Gasifier

2020 ◽  
Vol 18 (3) ◽  
Author(s):  
Rongbin Li ◽  
Mingzhuang Xie ◽  
Hui Jin ◽  
Liejin Guo ◽  
Fengqin Liu
Keyword(s):  
Coal Gasification ◽  
Three Dimensional ◽  
Reaction Model ◽  
Gas Temperature ◽  
Swirl Number ◽  
Entrained Flow ◽  
Gasification Process ◽  
Cold Gas Efficiency ◽  
Product Composition ◽  
Gas Efficiency

AbstractThe three-dimensional (3-D) comprehensive mathematical model was developed to simulate the coal gasification process in an entrained flow gasifier with a swirl burner. The models employed or developed includes the coal devolatilization model, the char combustion and gasification model, the gas homogeneous reaction model, the random-trajectory model, gas turbulence model, and the P-1 radiation model. The solution of models was executed based on the computational fluid dynamics (CFD). By qualitatively comparing the results at different swirl number, the significant influences of swirl on characteristics of coal gasification such as flow distributions, gas temperature and product composition including hydrogen (H2), carbon monoxide (CO), etc., and on the performance of coal gasification such as averaged exit product composition, carbon conversion rate and cold gas efficiency, were in detail discussed. Especially, a proper swirl number (S ≤ 0.65) in favor of gasification was found for the investigated gasifier in this paper.

scholarly journals Effect of Equivalence Ratio on the Rice Husk Gasification Performance Using Updraft Gasifier with Air Suction Mode

2020 ◽  
Vol 9 (1) ◽  
pp. 30-35
Author(s):  
Hendriyana Hendriyana
Keyword(s):  
Rice Husk ◽  
Equivalence Ratio ◽  
Volumetric Flow Rate ◽  
Unit Weight ◽  
Producer Gas ◽  
Heating Value ◽  
Cold Gas Efficiency ◽  
Gas Heating ◽  
Gas Efficiency ◽  
Cold Gas

Rice husk is the waste from agriculture industries that has high potential to produce heat and electricity through the gasification process. Air suction mode is new development for updraft rice husk gasification, where blower are placed at output of gasifier. The objective of this research is to examine these new configuration at several equivalence ratio. The equivalence ratio was varied at 32% and 49% to study temperature profile on gasifier, producer gas volumetric flow rate, composition of producer gas, producer gas heating value, cold gas efficiency and carbon conversion. The time needed to consume rice husk and reach an oxidation temperature of more than 700oC for equivalence ratio of 49% is shorter than 32%. Producer gas rate production per unit weight of rice husk increase from  2.03 Nm3/kg and 2.36 Nm3/kg for equivalence ratio of 32% and 49%, respectively. Composition producer gas for equivalence ratio of 32% is 17.67% CO, 15.39% CO2, 2.87% CH4, 10.62% H2 and 53.45% N2 and 49% is 19.46% CO, 5.94% CO2, 0.90% CH4, 3.46% H2 and 70.24% N2. Producer gas heating value for equivalence ratio 32% and 49% is 4.73 MJ/Nm3 and 3.27 MJ/Nm3, respectively. Cold gas efficiency of the gasifier at equivalence ratio 32% is 69% and at 49% is 55%.

scholarly journals ESTIMATIVA DA TEMPERATURA ADIABÁTICA DE CHAMA DA FORNALHA DE UMA CALDEIRA SIDERÚRGICA INDUSTRIAL

e-xacta ◽  
2016 ◽  
Vol 9 (2) ◽  
Author(s):  
Letícia Fabri Turetta ◽  
Andréa Oliveira Souza da Costa
Keyword(s):  
Flame Temperature ◽  
Operating Conditions ◽  
Adiabatic Temperature ◽  
Heating Value ◽  
Fuel Feed ◽  
Lower Heating Value ◽  
Thermoelectric Plant ◽  
Industrial Boiler ◽  
By Products ◽  
Lower Heating

<p>A indústria siderúrgica produz quatro subprodutos com significativa capacidade de geração de energia. Esses subprodutos podem ser utilizados como combustível na caldeira siderúrgica, equipamento da central termoelétrica. O objetivo deste estudo é propor uma modelagem para estimar a temperatura adiabática da chama da fornalha de uma caldeira siderúrgica com a variação de ar e combustível disponível. A técnica empregada consiste no princípio da Primeira Lei da Termodinâmica. O balanço de energia do sistema foi proposto definindo assim o modelo. A solução do modelo possibilita estimar a temperatura adiabática do sistema. Na indústria, a temperatura adiabática é determinada pelo poder calorífico inferior dos combustíveis. A metodologia proposta neste estudo faz com que não sejam necessários levantamentos experimentais do poder calorífico inferior. Os valores da temperatura adiabática simulados indicam que utilizar condições operacionais distintas na alimentação do combustível e do ar podem afetar significativamente o valor deste parâmetro. Nas simulação com a variação de ar, nota-se que a temperatura adiabática decresce com o acréscimo do excesso de ar. Tal resultado é esperado, uma vez que o aumento da massa, contida no sistema, diminui a eficiência energética do processo. Conclui-se que a metodologia proposta provou ser eficaz de descrever o sistema quando diferentes condições de alimentação são adotadas.</p><p> </p><p>ABSTRACT</p>Steel industry produces four by-products with significant capacity of energy generation. These products can be used as fuel at steel boiler, equipment thermoelectric plant. The objective of this study is to propose a modeling to estimate the adiabatic flame temperature furnace’s of an industrial boiler steelmaking with the variation of available air and fuel. The technique employed consists in principle of the First Law of Thermodynamics. The system's energy balance was proposed thus defining the model. The solution’s model enables to estimate the system’s  temperature of the adiabatic. In industry, the adiabatic temperature is determined by the fuel’s lower heating value. The methodology proposed in this study makes is not necessary experimental surveys of the lower heating value. The values at the adiabatic temperature simulated to indicate that use different operating conditions in the feed of fuel and air can significantly affect the value of this parameter. In the simulation with the variation in air, it is noted that the adiabatic temperature decreases with the increase of excess air. This result is expected since the increase of the mass contained in the system decreases the energy efficiency of the process. It is concluded that the methodology proved to be effective to describe the system when different air and fuel feed are adopted.

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