成果報告書詳細
管理番号20120000000265
タイトル*平成20年度中間年報 戦略的石炭ガス化・燃焼技術開発(STEP CCT)次世代高効率石炭ガス化技術開発(H19~H21)
公開日2012/6/9
報告書年度2008 - 2008
委託先名財団法人石炭エネルギーセンター 独立行政法人産業技術総合研究所 株式会社IHI
プロジェクト番号P07021
部署名環境部
和文要約1.研究開発の内容及び成果等
(1)低温ガス化
流動層を利用した水蒸気ガス化の基礎プロセス開発(IHI)
チャーの水蒸気ガス化反応は、ガス化によって発生したタールや揮発分等によって阻害されることが分かっている。数値解析ソフトにより、流動層ガス化条件における阻害効果の評価を行った。数値解析ソフトとしては、石炭の熱分解および水蒸気ガス化反応の定量評価が可能なPC Coal Lab.(Niksa Energy Associates社製)を用いた。計算の結果、熱分解ガスの分離により水蒸気ガス化反応の速度が向上し、50%炭素転換率を得るための滞留時間が40%程度低減可能なことが分かった。常圧流動層ラボガス化試験装置を用いた試験を行ったところ、熱分解過程の条件により水蒸気ガス化反応速度の向上効果が見られない場合もあることを明らかにした。これら結果より、ダウナー熱分解炉に必要な条件を検討した。
また、ガス化特性に対する水蒸気濃度の影響の把握、及び熱分解炉の仕様についての検討も着手している。
英文要約To develop next-generation exergy recuperation high-efficiency coal-fired power generation processes, a research and development program has been carried out on elemental gasification related technologies that will allow gasifier to accept fuel that has high water content or is difficult to crush. These technologies include low-temperature gasification, catalytic gasification, gasifier internal flow analysis and studies on combined cycle systems.

1) For low-temperature gasification, a continuous test on circulating fluidized bed steam gasification of a sub-bituminous coal using a laboratory-scale gasifier was conducted. The test revealed the effect of bed materials (silica sand and porous alumina particles) on gasification efficiency. The test also quantitatively revealed the difference in gasification rate between with and without a pyrolizer, i.e., the reactivity inhibition by volatile matter. In addition, a pressurized fluidized bed combustion furnace was used to conduct a char combustion experiment, which successfully showed how char combustion is affected by the combustion temperature, pressure and grain size.

2) Regarding catalytic gasification, firstly, the possibility of using natural mineral resources as gasification catalyst was examined. Natural soda ash was used to successfully cause coal to carry approximately 1.5 mass% Na. Char from this coal with Na catalyst showed a high rate of steam gasification conversion. Residual liquid of the hydrometallurgy process or waste liquid from the Ni-plating process was also effectively used to cause brown or sub-bituminous coal to carry Ni, which showed high activity. Meanwhile, support-type gasification catalysts with significant effects on activity were designed and prepared, and their performance was evaluated. Various catalysts were prepared from alumina carriers or perovskite carriers containing manganese oxide and different pore sizes and then their effects on the gasification characteristics were evaluated. Secondly, calcium oxide was used as an absorbent or chemical heat carrier during the chemical loop gasification process to determine effect of repetitive reactions on reactivity and physical properties. This experiment showed that the repetitive reactions slightly affects the reaction rate, but has almost no effect on the final conversion rate. Particles that went through 20 repetitive reactions showed a certain level of strength (equivalent to that of char).

3) For the gasifier internal flow analysis, a bench-scale circulating fluidized bed cold model was used to experimentally determine the basic flow characteristics. With the riser gas flow rate of ur = 6.0 m/s and the bubbling fluidized bed gas flow rate of ub = 3.0×10-2 m/s (ub /umf = 5.2), the experiment produced the maximum Gs (= 116 kg/(m2・s)). Also, the particle holdup was determined from the riser static pressure distribution. With εs ≤ 0.04 in the riser section, the formation of a diluted phase was found. Based on the results of the experiment, the conceptual design of a large-scale cold model was created. In addition, a flow analysis calculation code was developed for flow analysis simulation, and was used to analyze the particle residence time distribution in the gasifier.

4) In the study on combined cycle systems, the IGCC (integrated coal gasification combined cycle) and A-IGCC (advanced IGCC) were analyzed for potential performance when used with future compressors with assumed improved aerodynamic performance or with future heat exchangers with assumed improved capacity. As a result, the study showed that the A-IGCC could achieve a high efficiency of over 60% with 1700°C class gas turbines and would show even higher efficiency than the IGCC system using the entrained bed gasification technology. In terms of A-IGFC (advanced integrated coal gasification fuel cell combined cycle), efforts to improve the SOFC (solid oxide fuel cell) model were made.
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