According to the prehydrogenation and predistillation of catalytic reforming unit, this article utilize the pinch technology to analyze, find the energy bottleneck, simulate and optimize the whole heat exchange network by Aspen energy analyzer, compared with original heat exchange network , energy saving 3 735 kW (23.5%). Aiming at reduce the amount of utility and raising the profit for the enterprise.

Through macroanalysis, chemical composition analysis, metallographic observation, and SEM, the leakage reasons for joint of tube of header and coil tube of coal economizer was analyzed. The results show that the alloy element compositions of welded tubes and conversion strength both met the standard of GB 5310—2008. The grains at fusion zone and overheated zone were coarse and even formed widmanstaten structure which made the performance of the zone weaken. Leakage from the joint of tube of header and coil tube of coal economizer resulted in the micro cracks in the weakened region of fusion and overheated zone under the thermal stress. Though throughwall crack was not formed after micro cracks initiation, micro cracks resulted in crevice corrosion and the crevice corrosion accelerated crack propagation from the inside outwords, and eventually caused the leakage.