scholarly journals Effect of Gasification Temperature on Synthesis Gas Production and Gasification Performance for Raw and Torrefied Palm Mesocarp Fibre

2020 ◽  
Vol 19 (2) ◽  
pp. 138
Author(s):  
Najwa Hayati Abdul Halim ◽  
Suriyati Saleh ◽  
Noor Asma Fazli Abdul Samad

Biomass gasification is widely used for converting solid biomass into synthesis gas for energy applications. Raw biomass is commonly used as feedstock for the gasification process but it usually contains high moisture content and low energy value which lowering synthesis gas production. Thus, torrefaction as a pre-treatment process is necessary in order to upgrade the properties of feedstock for producing more synthesis gas production and improving gasification performance. The objective of this work is to study the effect of gasification temperature on the synthesis gas production and gasification performance using raw and torrefied palm mesocarp fibre (PMF). The gasification process is conducted using bubbling fluidized bed using steam as gasifying agent. Based on experimental work, by increasing gasification temperature from 650 – 900 °C, the compositions of hydrogen and carbon monoxide gases were enhanced greatly while carbon dioxide and methane gases were decreased for both raw and torrefied PMF. In terms of gasification performance, synthesis gas yield for raw and torrefied PMF is increased from 0.91 to 1.23 Nm3/kg and 1.10 to 1.35 Nm3/kg respectively. Besides, lower heating value (LHV) of torrefied PMF is 0.04 MJ/Nm3 higher than raw PMF at 900 °C. The result showed that the percentage of cold gas efficiency (CGE) reached maximum of 67% for raw PMF while carbon conversion (CC) at 85.6% for torrefied PMF at a gasification temperature of 900 °C. The higher CC obtained by torrefied PMF is because of the increment of carbon content from 45.2% to 53.7% as a result of torrefaction. Gasification temperature of 800 °C showed the best performance of the PMF gasification since the maximum performances of LHV is achieved and started to decrease once the gasification temperature is operated beyond 800 °C.

2019 ◽  
Vol 25 (4) ◽  
pp. 329-339
Author(s):  
João Cardoso ◽  
Valter Silva ◽  
Daniela Eusébio ◽  
Tiago Carvalho ◽  
Paulo Brito

A 2-D numerical simulation approach was implemented to describe the gasification process of olive pomace in a bubbling fluidized bed reactor. The numerical model was validated under experimental gasification runs performed in a 250 kWth quasi-industrial biomass gasifier. The producer gas composition, H2/CO ratio, CH4/H2 ratio, cold gas efficiency and tar content were evaluated. The most suitable applications for the potential use of olive pomace as an energy source in Portugal were assessed based on the results. A techno-economic study and a Monte Carlo sensitivity analysis were performed to assess the feasibility and foresee the main investment risks in conducting olive pomace gasification in small facilities. Results indicated that olive pomace gasification is more suitable for domestic purposes. The low cold gas efficiency of the process (around 20%) turns the process more appropriate for producer gas production in small cogeneration facilities. Olive pomace gasification solutions showed viable economic performance in small cogeneration solutions for agriculture waste-to-energy recovery in olive oil agriculture cooperatives. However, the slender profitability may turn the project unattractive for most investors from a financial standpoint.


2014 ◽  
Vol 699 ◽  
pp. 510-515
Author(s):  
Miao Miao Niu ◽  
Ya Ji Huang ◽  
Bao Sheng Jin

A model was developed for the enriched air-steam biomass gasification in a bubbling fluidized bed (BFB) gasifier using Aspen Plus. Restricted equilibrium method was used to eliminate the deviation caused by the diffusion effect of gas-particle. The model has been divided into three stages (drying and pyrolysis, partial combustion and gasification) for predicting the gasifier performance. Simulation results for gas composition, carbon conversion and cold gas efficiency versus oxygen percentage and steam to biomass ratio (S/B) were compared with the experimental results. Higher oxygen percentage improves the gasification process, increases the production of H2 and CO and results in better gasification efficiency. With increasing oxygen percentage, the production of CO2 and CH4 show decreasing trends. Steam injection enhances the H2 and CO2 production but decreases CO and CH4 production. Carbon conversion presents a slight decrease trend over the S/B range, while cold gas efficiency is first constant and then decreased.


Author(s):  
Mawa Mutaz ◽  
Ibrahim H.Elamin ◽  
Hamid M. Mustafa

Bagasse has traditionally inefficiently burned in boilers for steam and electricity generation which still suffers from significant inefficiencies creating; therefore there is a need for alternative processes to be analyzed. Among the biomass utilization technologies, biomass gasification is an attractive solution for utilizing biomass effectively. In this study Aspen Plus simulation package V8 was used to develop a model for the gasification of Sudanese sugar cane bagasse in a fluidized bed reactor for syngas production. The developed model is based on Gibbs free energy minimization applying the non-stoichiometric equilibrium method for optimization of the gasifier performance. The objective is to study the effect of important operating parameters including gasification temperature, steam to biomass ratio (SBR) and air to biomass ratio (ABR), on syngas composition, low heating value (LHV) of syngas and cold gas efficiency (CGE). The optimal values of syngas composition, LHV and CGE were located at gasification temperature range from 750C to 950C, steam to biomass ratio around 0.5 to 0.8 and air to biomass ratio values equal to or below 0.4.


Author(s):  
Rongbin Li ◽  
Mingzhuang Xie ◽  
Hui Jin ◽  
Liejin Guo ◽  
Fengqin Liu

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.


2012 ◽  
Vol 512-515 ◽  
pp. 575-578
Author(s):  
Hsien Chen ◽  
Chiou Liang Lin ◽  
Wun Yue Zeng ◽  
Zi Bin Xu

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.


2021 ◽  
Vol 12 (1) ◽  
pp. 98
Author(s):  
Andrej Chríbik ◽  
Marián Polóni ◽  
Ľuboš Magdolen ◽  
Matej Minárik

The aim of the presented article is to analyse the influence of synthesis gas composition on the power, economic, and internal parameters of an atmospheric two-cylinder spark-ignition internal combustion engine (displacement of 686 cm3) designed for a micro-cogeneration unit. Synthesis gases produced mainly from waste contain combustible components as their basic material (methane, hydrogen, and carbon monoxide), as well as inert gases (carbon dioxide and nitrogen). A total of twelve synthesis gases were analysed that fall into the category of medium-energy gases with lower heating value in the range from 8 to 12 MJ/kg. All of the resulting parameters from the operation of the combustion engine powered by synthesis gases were compared with the reference fuel methane. The results show a decrease in the performance parameters for all operating loads and an increase in hourly fuel consumption. Specifically, for the operating speed of the micro-cogeneration unit (1500 L/min), the decrease in power parameters was in the range of 7.1–23.5%; however, the increase in hourly fuel consumption was higher by 270% to 420%. The decrease in effective efficiency ranged from 0.4 to 4.6%, which in percentage terms represented a decrease from 1.3% to 14.5%. The process of fuel combustion was most strongly influenced by the proportion of hydrogen and inert gases in the mixture. It can be concluded that setting up the synthesis gas production in the waste gasification process in order to achieve optimum performance and economic parameters of the combustion engine for a micro cogeneration unit has an influential role and is of crucial importance.


Author(s):  
Dandan Wang ◽  
Sheng Li ◽  
Lin Gao

In this paper, a novel coal gasification technology used for Integrated Gasification Combined Cycle (IGCC) power plants is proposed, in which a regenerative unit is applied to recover syngas sensible heat to generate steam and then the high temperature steam is used to gasify coke from pyrolyzer. Through such a thermochemical regenerative unit, the sensible heat with lower energy level is upgraded into syngas chemical energy with higher energy level, and therefore a higher cold gas efficiency (CGE) is expected. The Aspen Plus Software is selected to simulate the novel coal gasification system. Then the exergy and Energy-Utilization Diagram (EUD) analyses are applied to disclose the plant performance enhancement mechanism. It reveals that 83.2% of syngas sensible heat can be recovered into steam agent and so the CGE is upgraded to 90%. And with the enhancement of CGE, the efficiency of an IGCC plant based on the novel gasification system can be as high as 51.82%, showing a significant improvement compared to 45.2% in a Texaco coal gasification based plant. At the same time, the exergy destruction of gasification process is reduced from 132.5MW to 98.4MW through thermochemical reactions. Lift of accepted energy level (Aea), and decrease of released energy level (Aed) and heat absorption (ΔH) contribute to the exergy destruction reduction in the gasification process. Additionally, since oxygen agent is no longer used in the IGCC, 34.5MW exergy loss in the air separation unit is avoided. Thereby the novel coal gasification technology proposed in this paper has a good thermodynamic performance and may provide a quite promising way for high efficient and clean coal utilization.


Energies ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 688 ◽  
Author(s):  
Mauro Villarini ◽  
Vera Marcantonio ◽  
Andrea Colantoni ◽  
Enrico Bocci

The present paper presents a study of biomass waste to energy conversion using gasification and internal combustion engine for power generation. The biomass waste analyzed is the most produced on Italian soil, chosen for suitable properties in the gasification process. Good quality syngas with up to 16.1% CO–4.3% CH4–23.1% H2 can be produced. The syngas lower heating value may vary from 1.86 MJ/ Nm3 to 4.5 MJ/Nm3 in the gasification with air and from 5.2 MJ/ Nm3 to 7.5 MJ/Nm3 in the gasification with steam. The cold gas efficiency may vary from 16% to 41% in the gasification with air and from 37% to 60% in the gasification with steam, depending on the different biomass waste utilized in the process and the different operating conditions. Based on the sensitivity studies carried out in the paper and paying attention to the cold gas efficiency and to the LHV, we have selected the best configuration process for the best syngas composition to feed the internal combustion engine. The influence of syngas fuel properties on the engine is studied through the electrical efficiency and the cogeneration efficiency.


Energies ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1367 ◽  
Author(s):  
Xiao ◽  
Wang ◽  
Zheng ◽  
Qin ◽  
Zhou

A co-gasification process was proposed both for treating alkaline organic wastewater and to promote coal gasification by the alkaline substances in situ. A catalytic gasification model was developed by introducing a catalytic correction factor to describe the catalytic effects quantitatively. An integrated process simulation was carried out using Aspen Plus equipped with FORTRAN subroutines. The model was verified using the root mean square error between the simulation results and experimental data from the literature. Syngas composition, cold gas efficiency, and carbon conversion efficiency were analyzed with respect to different operating conditions (reaction temperature, steam/coal ratio, and equivalence ratio). The optimal conditions are summarized based on a self-sufficient system by using sensitivity analysis: Gasification temperature of 700 °C, steam/coal ratio = 1.0, and equivalence ratio = 0.4.


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