報告書番号

W97015

タイトル（和文）

溶融石炭灰粒子の慣性分離技術の検討（その１）円柱列の粒子分離性能の数値解析と高粘度液体の微粒化特性

タイトル（英文）

INERTIA SEPARATION OF MOLTEN ASH PARTICLES (PART-1) -NUMERICAL SIMULATION OF INERTIA SEPARATORS USING CYLINDRICAL OBSTACLES AND DISPERSION PROPERTIES OF HIGHLY-VISCOUS LIQUID-

概要 （図表や脚注は「報告書全文」に掲載しております）

石炭直接燃焼ガスタービンシステムに適用する高温集塵方式として，慣性分離を選定し，その分離性能の数値解析に着手した。また高温下の集塵性能をコールド試験によって模擬するため，高粘度液体を用いた分離試験を計画したが，液滴粒子に燃焼器直後の灰粒子と同程度の粒径分布を持たせる必要が生じた。そのためグリセリンを用いて，その噴霧特性を検討した。分離性能の数値計算で円柱列の捕集効率を求めたところ，５０％分離径は２．６～５ミューｍであり，分離部の形状を変更し捕集性能を高める必要があることが判明した。また慣性パラメータを使用することで，部分捕集効率が１本の線でまとめられた。グリセリンの噴霧では平均粒径１０ミューｍ程度の液滴粒子の発生が可能で，燃焼器出口の灰に近い粒径分布が得られた。従って，コールド試験によって高温下の性能を模擬することがある程度可能であることが判明した。

概要 （英文）

A DIRECT COAL FUELED GAS TURBINE (DCFT) SYSTEM CAN ACHIEVE MUCH HIGHER THERMAL EFFICIENCY THAN CONVENTIONAL COAL FIRED POWER PLANTS BUT REQUIRES A HIGH-TEMPERATURE PARTICLE REMOVAL SYSTEM TO PROTECT THE GAS TURBINE. SINCE THE PARTICLES IN THE DCFT FLUE GAS ARE MOLTEN SLAG, INERTIA SEPARATORS COULD ACHIEVE EFICIENT GAS TURBINE PROTECTION. HOWEVER, EVALUATION OF INERTIA SEPARATORS REQUIRES INVESTIGATION OF THE COLLECTION EFFICIENCY AND DISCHARGE PROPERTIES OF SLAG COLLECTED FROM SEPARATORS. TO ESTIMATE THESE PROPERTIES, NUMERICAL SIMULATION AND COLD-FLOW TESTING USING HIGHLY VISCOUS FLUID PARTICLES ARE PLANNED. THIS REPORT CALCULATED THE COLLECTION EFFICIENCY OF CYLINDRICAL OBSTACLES AS A REFERENCE FOR INERTIA SEPARATORS, AND TESTED THE DISPERSION OF HIGHLY VISCOUS LIQUID BECAUSE THE COLD TEST REQUIRES A PARTICLE SIZE DISTRIBUTION SIMILAR ASH IN THE DCFT COMBUSTOR. IN THE NUMERICAL CALCULATION, CYLINDRICAL OBSTACLES WERE PLACED IN STAGGERED ROWS AND THE VOID RATIO WAS SET AT 40% OR 50%. THE FRACTIONAL COLLECTION EFFICIENCY CHANGED DEPENDING ON THE INLET FLOW VELOCITY TO THE SEPARATOR AND THE 50% CUT-OFF DIAMETER VARIED FROM 2.6 TO 5 M. HOWEVER, THE FRACTIONAL EFFICIENCY CONVERGED IN A LINE BY USING AN INERTIA PARAMETER, WHEN THE FLOWFIELD WAS SAME. THIS COLLECTION EFFICIENCY IS INSUFFICIENT TO PROTECT THE GAS TURBINE, BUT THERE IS A POSSIBILITY OF INCREASING THE EFFICIENCY BY CHANGING THE OBSTACLES. THE COLD TEST NEEDS TO GENERATE SMALL PARTICLES SIMILAR TO ASH PARTICLES IN A DCFT COMBUSTOR. ALTHOUGH IT WAS THOUGHT DIFFICULT TO GENERATE MICROMETER PARTICLES BY SPRAYING HIGHLY VISCOUS LIQUID, GLYCERINE PRODUCED SMALLER PARTICLES THAN WATER. SINCE THE SIZE DISTRIBUTION OF GLYCERINE PARTICLES WAS SIMILAR TO ASH PARTICLES IN A DCFT COMBUSTOR, THE COLD TEST IS REGARDED AS SUITABLE FOR SIMULATING HIGH-TEMPERATURE DUST REMOVAL.

報告者

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