Abstract: Based on the operation of 99.5% purity iso-butane production, a new process model was set up to calculate the process parameters for producing 99.9% purity iso-butane. Optimization of process parameters and production process was carried out. By updating the furnace and pressure-difference regulation system, the control of production process was more accurate and stable. Therefore, the n-butane content in the feed of iso-butane tower could be reduced to less than 0.085% from the original of less than 0.3%; the back flow of butane tower was increased to 20 m3/h; the temperature of both towers was controlled stably. Eventually the more than 99.9% high purity iso-butane product was obtained.

Key words: iso-butane, high purity, software simulation, optimization