HP40合金试样氧化表面的催化结焦

CATALYTIC COKE FORMATION ON THE OXIDIZED SURFACE OF HP40 ALLOY SPECIMEN

以石脑油为裂解原料,在850℃下进行了HP40合金试样氧化表面的催化结焦实验。采用扫描电子显微镜(SEM)、能量色散谱仪(EDS)和拉曼光谱表征了HP40合金试样的氧化层和结焦层。结果表明,HP40合金试样表面氧化层疏松、多孔,主要由(Cr,Fe)尖晶石和少量的Fe2O3组成。在结焦初始阶段,结焦速率较大,然而随着结焦实验时间的增加,结焦速率开始降低,最后趋于稳定值0.0084mg/(cm2.min)。在形核阶段,结焦层的粒子直径约为1μm,在催化结焦的后期,丝状焦直径约为0.2μm,当结焦机理为热裂解结焦时,丝状焦直径又增加到0.5μm。

A test for the catalytic coking was carried out on the oxidized surface of HP40 alloy specimen at 850℃ with naphtha as steam cracking material.The oxidized surface of HP40 alloy specimen and the cokes formed in the coking test were characterized by scanning electron microscopy （SEM）,X-ray energy dispersive spectroscopy （EDS） and Raman spectroscopy.The results showed that the oxidized surface of HP40 alloy specimen was a porous layer and mainly composed of （Cr,Fe）-spinel and a small amount of Fe2O3.The coking rate was high at the beginning of the coking test,while the coking rate decreased with the coking test time increasing,and finally reached the stable value of 0.0084 mg/（cm^2·min）.The diameter of coke particle was about 1 μm at the phase of nucleation,then about 0.2 μm at the end of catalytic coking.The diameter of filamentous coke increased to 0.5 μm again with the coking mechanism turning to the thermal cracking coking.