scholarly journals Experimental Study and Thermodynamic Analysis of Hydrogen Production through a Two-Step Chemical Regenerative Coal Gasification

2019 ◽  
Vol 9 (15) ◽  
pp. 3035 ◽  
Author(s):  
Li ◽  
He ◽  
Li
Keyword(s):  
Hydrogen Production ◽  
Production Process ◽  
Coal Gasification ◽  
Fixed Bed ◽  
H2 Production ◽  
Steam Gasification ◽  
Air Separation ◽  
The Novel ◽  
Separation Unit ◽  
Gasification Process

Hydrogen, as a strategy clean fuel, is receiving more and more attention recently in China, in addition to the policy emphasis on H2. In this work, we conceive of a hydrogen production process based on a chemical regenerative coal gasification. Instead of using a lumped coal gasification as is traditional in the H2 production process, herein we used a two-step gasification process that included coking and char-steam gasification. The sensible heat of syngas accounted for 15–20% of the total energy of coal and was recovered and converted into chemical energy of syngas through thermochemical reactions. Moreover, the air separation unit was eliminated due to the adoption of steam as oxidant. As a result, the efficiency of coal to H2 was enhanced from 58.9% in traditional plant to 71.6% in the novel process. Further, the energy consumption decreased from 183.8 MJ/kg in the traditional plant to 151.2 MJ/kg in the novel process. The components of syngas, H2, and efficiency of gasification are herein investigated through experiments in fixed bed reactors. Thermodynamic performance is presented for both traditional and novel coal to hydrogen plants.

Novel Coal-Steam Gasification With a Thermochemical Regenerative Process for Power Generation

2018 ◽  
Vol 140 (9) ◽  
Author(s):  
Dandan Wang ◽  
Sheng Li ◽  
Lin Gao ◽  
Handong Wu ◽  
Hongguang Jin
Keyword(s):  
Energy Level ◽  
Coal Gasification ◽  
Combined Cycle ◽  
Steam Gasification ◽  
Energy Utilization ◽  
Plant Performance ◽  
The Novel ◽  
Sensible Heat ◽  
Exergy Destruction ◽  
Separation Unit

In this paper, a novel high-efficiency coal gasification technology is proposed in which a regenerative unit is applied to recover syngas sensible heat to generate steam; then, the high-temperature steam is used to gasify coke from a pyrolyzer. Through such a thermochemical regenerative unit, the sensible heat with a lower energy level is upgraded into syngas chemical energy with a higher energy level; therefore, high cold gas efficiency (CGE) is expected from the proposed system. aspenplus software is selected to simulate the novel coal gasification system, and the key parameters are validated by experimentation. Then energy, exergy, and energy-utilization diagram (EUD) analyses are applied to disclose the plant performance enhancement mechanism. It is revealed that 83.2% of syngas sensible heat can be recovered into steam agent with the CGE upgraded to 90%. In addition, with the enhancement of CGE, the efficiency of an integrated gasification combined cycle (IGCC) based on the novel gasification system can be as high as 51.82%, showing a significant improvement compared to 45.2% in the general electric company (GE) gasification-based plant. In the meantime, the irreversible destruction of the gasification procedure is reduced to 25.7% through thermochemical reactions. The increase in the accepted energy level (Aea) and the decreases in the released energy level (Aed) and heat absorption (ΔH) contribute to the reduction in exergy destruction in the gasification process. Additionally, since the oxygen agent is no longer used in the IGCC, 34.5 MW exergy destruction in the air separation unit (ASU) is avoided.

The Puertollano IGCC Project, a 335 MW Demonstration Power Plant for the Main Electricity Companies in Europe

1995 ◽  
Vol 13 (6) ◽  
pp. 649-668 ◽  
Author(s):  
Ulpiano Sendin
Keyword(s):  
Power Plant ◽  
Flue Gas ◽  
Coal Gasification ◽  
Combined Cycle ◽  
Air Separation ◽  
Separation Unit ◽  
Gasification Process ◽  
The Status ◽  
Combined Cycle Plant ◽  
One Year

The paper describes the status of the 335 Mwe gross (ISO conditions) IGCC project of ELCOGAS in Puertollano/Spain based on the PRENFLO coal gasification process, at the beginning of its third year of engineering and construction. The project is funded within the Thermie programme of the Commission of the European Communities, being its first targeted project. The status of the IGCC project is presented. Coal gasification is based on the PRENFLO entrained-flow principle with dry fuel dust feeding. An almost complete raw gas desulphurization leads to very low SO2 contents in the flue gas. Sulphur from the coal will be available as elemental sulphur. By saturation of the desulphurized gas and the mixing with the nitrogen from the air separation unit the integrated power plant concept also achieves very low NOx contents in the flue gas. Commissioning tests for the combined cycle plant fed with natural gas will start during mid-1995. and will be followed by one year plant operation, before commissioning of the IGCC power plant.

scholarly journals CFD researched on rice husk gasification in a pilot fixed bed up-draft system

2016 ◽  
Vol 19 (3) ◽  
pp. 96-109
Author(s):  
Phung Thi Kim Le ◽  
Viet Tan Tran ◽  
Thien Luu Minh Nguyen ◽  
Viet Vuong Pham ◽  
Truc Thanh Nguyen ◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Rice Husk ◽  
Alternative Energy ◽  
Fossil Fuels ◽  
Fixed Bed ◽  
Steam Gasification ◽  
Actual Process ◽  
Ansys Fluent ◽  
Alternative Energy Sources ◽  
Gasification Process

Finding alternative energy sources for fossil fuels was a global matter of concern, especially in developing countries. Rice husk, an abundant biomass in Viet Nam, was used to partially replace fossil fuels by gasification process. The study was conducted on the pilot plant fixed bed up-draft gasifier with two kind of gasification agents, pure air and air-steam mixture. Mathematical modeling and computer simulations were also used to describe and optimize the gasification processes. Mathematical modeling was based on Computational Fluid Dynamics method and simulation was carried by using Ansys Fluent software. Changes in outlet composition of syngas components (CO, CO2, CH4, H2O, H2) and temperature of process, in relation with ratio of steam in gasification agents, were presented. Obtained results indicated concentration of CH4, H2 in outlet was increased significantly when using air-steam gasification agents than pure air. The discrepancies among the gasification agents were determined to improve the actual process.

scholarly journals Assessment of coal gasification in a pressurized fixed bed gasifier using an ASPEN plus and Euler–Euler model

2020 ◽  
Vol 7 (3) ◽  
pp. 516-535
Author(s):  
Tamer M. Ismail ◽  
Mingliang Shi ◽  
Jianliang Xu ◽  
Xueli Chen ◽  
Fuchen Wang ◽  
...  
Keyword(s):  
Coal Gasification ◽  
Fixed Bed ◽  
Size Variation ◽  
Aspen Plus ◽  
Two Dimensional ◽  
Cfd Model ◽  
Gas Generation ◽  
Gasification Process ◽  
Promising Tool ◽  
Euler Model

Abstract With the help of Aspen Plus, a two-dimensional unsteady CFD model is developed to simulate the coal gasification process in a fixed bed gasifier. A developed and validated two dimensional CFD model for coal gasification has been used to predict and assess the viability of the syngas generation from coal gasification employing the updraft fixed bed gasifier. The process rate model and the sub-model of gas generation are determined. The particle size variation and char burning during gasification are also taken into account. In order to verify the model and increase the understanding of gasification characteristics, a set of experiments and numerical comparisons have been carried out. The simulated results in the bed are used to predict the composition of syngas and the conversion of carbon. The model proposed in this paper is a promising tool for simulating the coal gasification process in a fixed bed gasifier.

Comparative Analysis of Advanced H2/Air Cycle Power Plants Based on Different Hydrogen Production Systems From Fossil Fuels

2004 ◽  
Author(s):  
M. Gambini ◽  
M. Vellini
Keyword(s):  
Hydrogen Production ◽  
Power Plants ◽  
Fossil Fuels ◽  
Coal Gasification ◽  
Fossil Fuel ◽  
H2 Production ◽  
Combined Cycle ◽  
Methane Reforming ◽  
Steam Methane Reforming ◽  
Steam Methane

In this paper two options for H2 production by means of fossil fuels are presented, evaluating their performance when integrated with advanced H2/air cycles. The investigation has been developed with reference to two different schemes, representative both of consolidated technology (combined cycle power plants) and of innovative technology (a new advance mixed cycle, named AMC). The two methods, here considered, to produce H2 are: • coal gasification: it permits transformation of a solid fuel into a gaseous one, by means of partial combustion reactions; • steam-methane reforming: it is the simplest and potentially the most economic method for producing hydrogen in the foreseeable future. These hydrogen production plants require material and energy integrations with the power section, and the best connections must be investigated in order to obtain good overall performance. The main results of the performed investigation are quite variable among the different H2 production options here considered: for example the efficiency value is over 34% for power plants coupled with coal decarbonization system, while it is in a range of 45–48% for power plants coupled with natural gas decarbonization. These differences are similar to those attainable by advanced combined cycle power plants fuelled by natural gas (traditional CC) and coal (IGCC). In other words, the decarbonization of different fossil fuels involves the same efficiency penalty related to the use of different fossil fuel in advanced cycle power plants (from CC to IGCC for example). The CO2 specific emissions depend on the fossil fuel type and the overall efficiency: adopting a removal efficiency of 90% in the CO2 absorption systems, the CO2 emission reduction is 87% and 82% in the coal gasification and in the steam-methane reforming respectively.

scholarly journals Analysis of potential energy and environmental impact from coal gasification through simulation of plasma gasification process of Indonesian low-rank coal

2021 ◽  
Vol 24 (1) ◽  
pp. 57-70
Author(s):  
Priyo Sesotyo ◽  
◽  
Muhammad Nur ◽  
Oki Muraza ◽  
◽  
...  
Keyword(s):  
Environmental Impact ◽  
Coal Gasification ◽  
Energy Content ◽  
Electric Energy ◽  
Chemical Properties ◽  
H2 Production ◽  
Low Rank ◽  
Energy Potential ◽  
Plasma Gasification ◽  
Gasification Process

Indonesia's coal reserve is abundant with its lower price and widely distributed than oil and natural gas. However, the coal emits high carbon dioxide gas (CO2) and sulfur compounds (H2S, SOx) to the environment during utilization. Plasma gasification can overcome those lacks using the external electric energy through a plasma torch. The chemical properties of coal have impacts on the energy content and environmental benchmarking. Using steam as a gasifying agent should be adequate to produce H2 and CO syngas. A research has been carried out to analyze and understand the benefit of using different gasifying agent for maximizing the H2 production and minimizing the environmental impact. Pure Steam (PS) gasifying agent to coal ratio of 0.4 has shown 43.76% H2 composition in syngas and cold gasification efficiency (CGE) with 37.71%. The PS to coal ratio of 0.2 has a significant carbon conversion efficiency of 4.75% and the PS to coal ratio of 0.6 has a gross energy potential of 86.5 kW. Using such the PS is significantly better than the mixture of steam oxygen (SO) as the gasifying agent since it needs to have a greater SO flow rate to have the SO to coal ratio of 1.00.

scholarly journals Examination of steam gasification of coal with physically mixed catalysts

2019 ◽  
Vol 21 (4) ◽  
pp. 51-57 ◽  
Author(s):  
Katarzyna Śpiewak ◽  
Grzegorz Czerski ◽  
Agnieszka Sopata
Keyword(s):  
Coal Gasification ◽  
Steam Gasification ◽  
Conversion Degree ◽  
Process Time ◽  
Gasification Process ◽  
Kinetics Of Formation ◽  
Short Time ◽  
Kinetics Of ◽  
Positive Effect

Abstract The aim of this study was to analyse the steam gasification process of ‘Janina’ coal with and without Na-, K- and Ca-catalysts. The catalysts were physically mixed with the coal due to the simplicity of this method, short time of execution and certainty that the amount of catalyst is exactly as the adopted one. The isothermal measurements were performed at 800, 900 and 950°C and a pressure of 1 MPa using thermovolumetric method. The obtained results enabled assessment of the effect of analysed catalysts on the process at various temperatures by determination of: i) carbon conversion degree; ii) yield and composition of the resulting gas; and iii) kinetics of formation reactions of main gas components – CO and H2. The addition of catalysts, as well as an increase in operating temperature, had a positive effect on the coal gasification process – reactions rates increased, and the process time was reduced.

Air-Steam Gasification of Dairy Biomass Using Small Scale Fixed Bed Gasifier

2009 ◽  
Author(s):  
Gerardo Gordillo ◽  
Kalyan Annamalai
Keyword(s):  
Energy Conversion ◽  
Fixed Bed ◽  
Energy Conversion Efficiency ◽  
Steam Gasification ◽  
Small Scale ◽  
Gasification Process ◽  
Green Power ◽  
Endothermic Process ◽  
Conversion Efficiencies ◽  
Rich Mixtures

The composition of gases obtained from gasification of biomass fuels depends principally upon parameters like fuel and oxidizing medium supplied, equivalence ratio (Φ), steam-fuel ratio (S:F), pressure, reaction temperature, and residence time in the gasifier. Gasification with steam only is an endothermic process which produces rich mixtures of CO and H2 while gasification with air-steam may not require heat input in order to produce H2 rich mixtures of CO and CO2. Furthermore, gases produced by gasification with-air-steam can be supplied to a shift reactor to produce mixtures of H2, CO2, and N2. When pure O2 is used instead of air, the H2 separated from CO2 can be used for in situ sustainable green power generation. The gasification process can handle low quality fuel and larger sized particles. While coal has higher fixed carbon (FC) providing more heat for gasification, the Dairy biomass (DB) selected in current study has lower FC and hence contributes less heat. While most of the past studies deal with gasification of coal, current study concentrates on DB as fuel. Experimental results are presented for gasification of i) dairy biomass (DB) and ii) DB ash blends (DBAB) using a 10 KW fixed bed counter-flow gasifier and air-steam as oxidizing source. The results show that the reactor operates almost adiabatically. The effects of the Φ and S:F ratio on peak temperatures, gas composition, gross heating value of the products (HHV), and energy conversion efficiency (ECE) are investigated. A mass spectrometer has been used to analyze the composition of gases in real time continuously. Increasing Φ or S:F increases the production of H2 and CO2 but decreases the production of CO; thus, the reaction of CO+H2O→CO2+H2 seems to control the composition of gases. The operating parameters include 1.59<Φ<6.36 and 0.36<S:F<0.8. Energy Conversion efficiencies (ECE) range from 0.26 to 0.80.

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