Two-stage Entrained Flow Coal Gasifier Research Articles

Polycyclic aromatic hydrocarbons (PAHs) and soot formations under different gasifying agents: Detailed chemical kinetic analysis of a two-stage entrained flow coal gasifier

The injection of CO2 with coal into coal gasifier is a promising approach to achieve CO2 recirculation. Predicting the formation and evolution of polycyclic aromatic hydrocarbons (PAHs) and soot during coal gasification is particularly important as their presence poses challenges to the gasifier operation and environment. However, the effect of CO2 injection on their formation must be elucidated in more detail to optimize the gasifier design. This work investigates PAHs and soot formations in gas-phase reactions under different gasifying agents (Air, O2/CO2, O2/H2O) in a two-stage entrained flow coal gasifier using a detailed chemical kinetic model (DCKM). Under the O2/CO2– and O2/H2O-blown conditions, aromatics reforming was progressed whereas the yields of tar and soot were effectively suppressed. The benzene was observed as the most abundant PAHs species, followed by naphthalene and acenaphthalene. Regarding the relative oxygen concentration, the conversion behavior of aromatics was significantly influenced in the O2/CO2-blown condition, while the somewhat effect was found in the O2/H2O-blown condition. Tar yield peaked at 50% relative oxygen concentration in the O2/CO2-blown condition. The present finding may have practical significance in the O2/CO2-blown gasifier to facilitate CO2 recirculation for the oxy-fuel IGCC system.

Polycyclic Aromatic Hydrocarbons (Pahs) and Soot Formations Under Different Gasifying Agents: Detailed Chemical Kinetic Analysis of a Two-Stage Entrained Flow Coal Gasifier

Polycyclic Aromatic Hydrocarbons (Pahs) and Soot Formations Under Different Gasifying Agents: Detailed Chemical Kinetic Analysis of a Two-Stage Entrained Flow Coal Gasifier

2-5 詳細反応化学速度モデルを用いた噴流床石炭ガス化炉における芳香族炭化水素の改質およびスス生成シミュレーション

2-5 詳細反応化学速度モデルを用いた噴流床石炭ガス化炉における芳香族炭化水素の改質およびスス生成シミュレーション

1-2-2 石炭ガス化炉内硫黄化合物転換特性の詳細化学反応速度モデルに基づく解析

1-2-2 石炭ガス化炉内硫黄化合物転換特性の詳細化学反応速度モデルに基づく解析

Verification Test Results of 50 t/d O2/CO2-blown Two-stage Entrained Flow Coal Gasifier and Development into Commercial Scale Gasifier

熱効率の高いCO2回収型火力発電システムとしてOxy-fuel IGCCの開発が進められている。Oxy-fuel IGCCに適用されるO2/CO2吹きガス化プロセスの検証のため，石炭処理量が日量50 ton（50 t/d）規模のO2/CO2吹きガス化試験を初めて行った。スラグ流下特性は良好で，ガス化炉を安定して運転できることを確認した。主要生成ガス成分の計測の結果，50 t/d炉の特性は従来の予測手法で検討可能であることが確認された。O2/CO2吹きガス化で生成ガス中のハイドロカーボン計測を行い，運転条件の調整でハイドロカーボン量が調整可能であることが示唆された。さらにガス化試験にて確認した予測手法を適用して商用規模Oxy-fuel IGCCシステムへの適用性を検討した。

No.45 加圧二段噴流床石炭ガス化炉のガス化特性に関する検討 : ガス化剤酸素濃度の影響(ガス化・燃焼・液化(5))

No.45 加圧二段噴流床石炭ガス化炉のガス化特性に関する検討 : ガス化剤酸素濃度の影響(ガス化・燃焼・液化(5))

Numerical investigation of effects of CO2 recirculation in an oxy-fuel IGCC on gasification characteristics of a two-stage entrained flow coal gasifier

Effects of CO2 recirculation within an oxy-fuel IGCC plant on a gasification characteristics of a two-stage entrained flow coal gasifier was numerically investigated by means of a three-dimensional unsteady Reynolds-averaged Navier-Stokes(RANS) simulation. The RNG k−ε model and the Eulerian-Lagrangian manner were used to consider the effect of turbulence and the particles' motions, respectively. A char gasification model in which the Langmuir-Hinshelwood formulation was coupled with the random pore model was employed to estimate gasification reaction rate. Results showed that the gasification performance such as the per pass carbon conversion efficiency for the oxy-fuel condition in which CO2 replaced N2 in the primary and secondary gas flows was in the same level for the air-blown condition in which O2 flowed into the gasifier with N2, while the gaseous temperature drastically decreased for the former case. It was also found that the gaseous temperature was recovered to the same level for the air-blown condition with at least more than 35% of oxygen concentration in the gasifying agent and simultaneously the highly gasification performance was observed. It is essential to control O2 and CO2 concentrations in the gasifying agent to turn the CO2 recirculation to advantage in utilization of the O2-CO2 blown gasifier in the oxy-fuel IGCC system.

Performance Prediction of a Pressurized Entrained Flow Ultra-Fine Coal Gasifier

Gasification is an efficient method of producing clean synthetic gas which can be used as fuel for electric generation and chemical for industries use. Gasification process simulation of coal inside a generic two-stage entrained flow gasifier to produce syngas was undertaken. Numerical simulation of the oxygen blown coal gasification process inside a two-stage entrained coal gasifier is studied with the commercial CFD solver ANSYS FLUENT. The purpose of this study is to use CFD simulation to improve understanding of the gasification processes in the state of art two-stage entrained flow coal gasifier. Three dimensions, Navier-Stokes equations and species transport equations are solved with the eddy-breakup reaction model to predict gasification processes. The influences of coal/water slurry concentration and O2/coal ratio on the gasification process are investigated. The coal-to-water slurry concentrations in this study were 0.74 and O2/coal ratio is 0.91. Coal slurry fed the predicted concentration of 47.7% and CO was 25% with higher syngas heating value of 27.65 MJ/kg. The flow behavior in the gasifier, especially the single fuel injection design on the second stage, is examined and validated against available data in the literature.

A Study on Gasification Reactivity of Pressurized Two-Stage Entrained Flow Coal Gasifier.

CRIEPI and Mitsubishi Heavy Industry, Ltd. have developed a pressurized two-stage entrained flow coal gasifier using a 2T/D bench scale gasifier. This type of gasifier was adopted for the 200T/D pilot plant project. The pilot plant test operation was started in March 1991 and was successfully finished in February 1996. Based on the results from the pilot plant, all Japanese electric power companies decided to construct the demonstration plant using the pressurized two-stage entrained flow type gasifier. In this type of coal gasifier, the product char is recycled to improve its efficiency. Using the experimental data of 2T/D gasifier, this report examines gasification characteristics such as product gas composition, cold gas efficiency and carbon conversion efficiency. Then, the effect of char recycle on gasifying efficiency and amount of product char is examined. Furthermore, per pass carbon conversion efficiency and fixed carbon conversion efficiency are evaluated.

Examination of gasification characteristics of pressurized two-stage entrained flow coal gasifier (comparison of basic performance with 2 T/D and 200 T/D coal gasifier)

Alkali metal, sulphur, and chlorine species released during coal gasification are of concern, because they can lead to problems in colder parts of the plant. Therefore, hot gas cleaning technology is recently under development. This clean-up strategy requires a comprehensive knowledge of the release characteristics of inorganic compounds. The principal objective of this work was to provide details of the influence of pressure on the release of key chemical species, e.g. sodium, potassium, sulphur, and chlorine. Hence, a total of 19 different coals were investigated in lab-scale gasification experiments in an electrical heated pressurised furnace at absolute pressures of 2, 4, and 6 bar in an atmosphere of He/7.5v%O2 at 1325 °C. Hot gas analysis was carried out by molecular beam mass spectrometry. The quantitative results showed a decreasing release of 34H2S+, 36HCl+, 39K+/39NaO+, 58NaCl+, 64SO2+, and 74KCl+ with increasing pressure. The discussion was supported by thermodynamic calculations.

Gasification rate analysis of coal char with a pressurized drop tube furnace

Two coal chars were gasified with carbon dioxide or steam using a Pressurized Drop Tube Furnace (PDTF) at high temperature and pressurized conditions to simulate the inside of an air-blown two-stage entrained flow coal gasifier. Chars were produced by rapid pyrolysis of pulverized coals using a DTF in a nitrogen gas flow at 1400°C. Gasification temperatures were from 1100 to 1500°C and pressures were from 0.2 to 2 MPa. As a result, the surface area of the gasified char increased rapidly with the progress of gasification up to about six times the size of initial surface area and peaked at about 40% of char gasification. These changes of surface area and reaction rate could be described with a random pore model and a gasification reaction rate equation was derived. Reaction order was 0.73 for gasification of the coal char with carbon dioxide and 0.86 for that with steam. Activation energy was 163 kJ/mol for gasification with carbon dioxide and 214 kJ/mol for that with steam. At high temperature as the reaction rate with carbon dioxide is about 0.03 s −1, the reaction rate of the coal char was controlled by pore diffusion, while that of another coal char was controlled by surface reaction where reaction order was 0.49 and activation energy was 261 kJ/mol.

Examination of Gasification Characteristics of Pressurized Two-Stage Entrained Flow Coal Gasifier. Comparison of Basic Performance with 2T/D and 200T/D Coal Gasifier.

The program for the 200T/D coal gasification pilot plant was initiated in 1986 and successfully completed in 1996. In this program, a two-stage pressurized air-blown entrained flow coal gasifier was adopted, jointly developed by Central Research Institute of Electric Power Industry (CRIEPI) and Mitsubishi Heavy Industry, Ltd. using a 2T/D bench scale gasifier. In the 200T/D pilot plant, domestic Taiheiyo coal and Australian Moura, Warkworth coal were used for test operations. The commissioned tests of these three types of coals have been carried out in a 2T/D gasifier, prior to the pilot plant operation. The gasification characteristics of 2T/D and 200T/D gasifiers were evaluated. At the same gasifier air ratio, per pass fixed carbon conversion efficiency of the 2T/D gasifier is about 10% lower than that of the 200T/D gasifier and the heat absorption rate to the gasifier wall of the 2T/D gasifier is about 2% higher than that of the 200T/D gasifier.

Examination of Gasification Characteristics of Pressurized Two-Stage Entrained Flow Coal Gasifier. Comparison of Basic Performance with 2T/D and 200T/D Coal Gasifier.

The program for a 200T/D entrained flow coal gasification pilot plant was initiated in fiscal year 1986 and successfully finished fiscal year 1996. In this program, a two stage pressurized air-blown entrained flow coal gasifier was adopted, which CRIEPI and Mitsubishi Heavy Industry, Ltd, have developed jointly using a 2T/D bench scale P.D.U.. In the 200T/D pilot plant, domestic Taiheiyo coal, and Australian Moura, Warkworth coal were used for test runs. On the other hand, the commissioned tests of these 3 types of coals by NEDO/IGC Association have been carried out in CRIEPI's 2T/D coal gasifier, prior to the pilot plant operation. The research results obtained by the 2T/D gasifier were reflected in the operation of the pilot plant. From gasification test results with 2T/D and 200 T/D gasifiers, the gasification characteristics such as carbon conversion efficiency, cold gas efficiency and heat absorption rate to gasifier wall were evaluated.

2304 加圧二段噴流床石炭ガス化炉におけるガス化反応性に関する検討

CRIEPI and Mitsubishi Heavy Industry, Ltd. have developed a pressurized two-stage entrained flow coal gasifier using a 2T/D bench scale gasifier. This type of gasifier was adopted for the 200T/D pilot plant project. The pilot plant test operation was started in March 1991 and was successfully finished in February 1996. Based on the results from the pilot plant, all Japanese electric power companies decided to construct the demonstration plant using the pressurized two-stage entrained flow type gasifier. In this type of coal gasifier, the product char is recycled to improve its efficiency. Using the experimental data of 2T/D gasifier, this report examines gasification characteristics such as product gas composition, cold gas efficiency and carbon conversion efficiency. Then, the effect of char recycle on gasifying efficiency and amount of product char is examined. Furthermore, per pass carbon conversion efficiency and fixed carbon conversion efficiency are evaluated.

Operational results of 200 t/d IGCC pilot plant in Nakoso

The New Energy and Industrial Technology Development Organization (NEDO), Engineering Research Association for Integrated Coal Gasification Combined Cycle Power Systems (IGC Association) recently succeeded in developing an air blown two-stage entrained flow coal gasifier and a fixed bed hot and dry gas clean-up system with the achievement of one month stable and continuous operation at 200 tons per day IGCC pilot plant in Nakoso. These technologies were very challenging but are the most attractive for power generation because of the significantly thermally increased efficiency due to air blown operation and few heat losses in the clean-up process. Based on these successes, the high performance of the IGCC energy effective fuel utilization and environmental compatibility has been further enhanced.

Development of a 2T/D pressurized two-stage entrained flow coal gasifier. 1st, Report, Characteristics of coal gasification.

Experimental study using a 2T/D air-blown pressurized two-stage entrained flow coal gasifier was initiated in 1983. Various tests and research efforts with the gasifier have been conducted to investigate the characteristics of coal gasification, slag discharge, etc. Sixteen bituminous coals have been tested and the total gasification time (as of August 1989) has reached 1500 hours. This report presents the experimental test results on the coal gasification characteristics for 5 typical coals. As a result of the gasification tests, it should be noted that steady discharge of molten slag was accomplished under air-blown conditions also for high-ash-melting coals. The HHV of the product gas, cold gas efficiency, and carbon conversion efficiency were highly dependent on the air ratio and the carbon recycle rate. The per pass carbon conversion efficiency and the amount of product char were affected by the gasifier air ratio and the coal types.