Performances And Simulation Of A30000nm~3/h Air Separation Rectifying Column Of Yankuang Guohong Chemical Co.

Air separation is one of the typical public utility engineering projects, whichutilizes air as the raw material to get pure oxygen, nitrogen and argon as the mainproducts. Air separation is widely used in iron and steel, chemical, coal gasificationand papermaking industries as well as in other fields. The main methods for airseparation include the newly occurred noncryogenic and traditional cryogenictechnologies. The former has the advantages of simple operation and low cost, but itis hard to produce large amounts of products while still keep high product purities.The latter has the drawbacks of complicated process and high cost, but it is a welldeveloped technology with a great reliability and has been widely adapted in industryfor producing high purity of oxygen and nitrogen in large scales.The production process of500kt methol/a of Yankuang Guohong Chemical Co.,Ltd, was briefly introduced with a focus on the accessory2×30000Nm~3/h internalcompression air separation system. The distillation separation unit of the airseparation system was simulated using the chemical process simulation softwareChemCad by choosing appropriate state equations. The simulation results were foundto be in well agreements with the production data when the operation is within thedesigned flexibility of70-110%, indicating the validity of the simulation.The feasibility of expending the current methanol production system from500kt/a to600kt/a was evaluated with a focus on the capacity of the air separation unit. Ithas been concluded that the pre-cooling purification system, pressurized expander andfractionation system can meet the requirements of expension any transformations.However, the air flows from the current two screw machines need to be combined andincorporated into the gas outlet of the air compressor to increase the gas flow into thetower. In addition, owing to the higher-than-designed outlet gas temperature of thepressurized expander, suitable measures must be taken to meet the design randexpension requirements by synergistically considering the structural design, flowsheetarrangement and over, operation procedure of the cooler of the pressurized expender.Moreover, the interstage cooler of the air compressor needs to be replaced by a newone with a higher cooling capacity and the cooling of the bearing of the liquid oxygenpump needs to be performed using water instead of air.