Grey decision on oil distillation tower top exchangers maintenance overhaul

Exchangers on the top of distillation tower exposed to wash erosion seriously when Shengli refinery processed Middle-east crude oil. Used grey system theory, aimed at general tube-shell exchangers and helix-baffled structure, tube of 20 carbon steel with TH847 coating, 20 steel aluminizing, 316L and dual phase steel, carried on grey decision. For exchangers rebuilding project, grey target decision shows that helix-baffled exchangers with 20+TH847 coating tube is the best preference plan, while grey incidence decision shows that the helix-baffled structure with 20 carbon steel aluminizing tube is the preferential plan. In general, helix-baffled structure is better than general contractures, should adopt advanced manufacture technology to lower the fabricate difficulty.