A Study of Chemical Cleaning to Remove Deposits in a Cold Box: The 10th Refinery of South Pars

The 10th Refinery of the South Pars Gas Complex in Iran experienced a notable decrease in gas production due to the formation of deposits in the cold box. To tackle this issue, a comparison of data was conducted before and after the refinery's annual turnaround. After extensive investigations, it was determined that the Xylene solvent wash was the most suitable solution to address the cold box pressure drop in the ethane recovery unit. The scale of the cold box studied in this article is significant in terms of dimensions and flow rate. The Phase 19 gas plant encountered the issue in interesting way according to limitations such as large-scale continuous production. A chemical wash procedure was designed and implemented during the refinery shutdown, which resulted in a successful reduction in the cold box pressure drop and an increase in production rate by approximately 188 tons/hour. This led to a yearly revenue increase of approximately 387 million USD, emphasizing the significance of addressing deposit buildup in cold boxes to maintain optimal gas production and achieve substantial financial gains.