| 摘要 |
PURPOSE:To develop a water cooling wall tube of a coal gasifying furnace having the excellent resistance to corrosion by high-temp. gas and steam oxidation by using an austenitic stainless steel added with Al and rare earth element as the water cooling wall tube material for the upper part of the coal gasifying furnace. CONSTITUTION:The inside of the coal gasifying furnace is heated by the formed gas to an extremely high temp. Refractories are used for the cooling wall part in the lower part of the gasifying furnace but the water cooling wall tube made of a heat resisting steel such as austenitic stainless steel is used for the cooling wall material in the upper part. The cooling water in the cooling wall tube 5 in the upper part of the gasifying furnace 2 is heated to 550-650 deg.C in order to be used as the high-temp. steam for power generation and since corrosive gases such as H2S co-exist in the formed crude gas 7, 0.5-5% Al and 0.01-0.5% rare earth element such as Ce, Y or La are added alone or in combination to the 18-8 austenitic stainless steel contg. <0.15% C, <1.0% Si, <2.0% Mn, 8-14% Ni, and 16-20% Cr as the cooling wall tube 5, by which the corrosion and oxidation by the formed gas and steam at high temp. are prevented.
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