Chemical Recovery of Green House Effect Gas by Using Waste Heat

该项目的目的是从根本上研究一种利用化学吸热反应的新型热回收系统的可能性，其中选取炼钢工业的高温熔渣和甲烷蒸汽重整反应。研究分为两个课题。1）熔渣催化性能：在不同温度、压力、流量和熔渣成分条件下测定CH4 H2O=3H2 CO和CH4 CO2=2H2 2CO的重整率，然后用Arrehnius型方程进行关联。结果清楚地表明反应发生在熔渣表面，没有积碳。结果还表明，反应的完成需要扩大气体和炉渣之间的表面积。2）工艺设计：两种方法都存在炉渣和反应气体之间进行换热的可能性。一种是顶部/底部吹气式，另一种是炉渣粉碎式。对于前者，空腔的形状是评价气体与炉渣接触面积的关键信息。但此类实验数据尚未见报道。在本研究中，我们利用X射线CT方法成功地观察到了1550摄氏度下的空腔。形状不是抛物线形，而是圆柱形。这些信息将有助于工艺设计。对于粉碎熔融炉渣，转杯雾化器可以有效地控制炉渣的尺寸和形状。随着转速的增加，所得颗粒逐渐减少，呈均匀的球形。所获得的粒子数据由报道的半理论方程解释。

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.