Chemical Recovery of Green House Effect Gas by Using Waste Heat

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The aim of this project was to fundamentally study a possibility of new heat recovery system by using chemical endothermic reaction, in which high-temperature molten slag from the steel-making industry and the methane steam reforming reaction were selected. The research was classified into the two subjects.1) Catalytic Property of Molten Slag :The reforming rates of CH4+H2O=3H2+CO and CH4+CO2=2H2+2CO were measured under the different conditions of temperature, pressure, flowrate and slag compositions, and then was correlated by Arrehnius type equations. The results showed clearly the reaction occurs on the surface of molten slag without carbon deposition. The results also suggested the enlargement of surface area between gas and slag is needed for the completion of the reaction.2) Process Design :The two methods have a possibility of the heat exchanger between slag and reactant gas. One is top/bottom gas blowing type and another, slag pulverization.Regarding the former, the shape of cavity is critical information for evaluating contacting area between gas and slag. However, such experimental data was not reported yet. In this study, we successfully observed the cavity under 1550 degree Celcius by using X-ray CT method. The shape was not parabolic, but cylindrical. This information will be helpful for process designing.For pulverizing molten slag, the rotary cup atomizer was effective for controlling the size and shape of the slag. With increasing the rotating speed, the obtained particle decreased with uniform spherical shape. The obtained data of the particle was explained by the reported, semi-theoretical equations.