Location: Jiangsu Province, China

Start-up time: Sep. 2014

Background:

It was hard to meet excellent grade of new national standard because aldehyde content of EO product in EO tower was high. Once product from top of column was larger than 3t/h, it was easy to exceed national standard for EO product due to high content of water and aldehyde, such as aldehyde content could be larger than 70ppm. The real capacity was 25,000t/a EO product, much less than 36,000t/a at design point, after new national standard was implemented. Client planned to revamp EO tower to make aldehyde content less than 30ppm, which was required for excellent grade of new national standard, and turn-up should be increased to 150%.

Solution:

ZEHUA successfully established model for predicting ppm level of aldehyde content according to operation parameters from site and analysis results. ZEHUA recommended client to change operation parameters based on model. It was also verified consistency for results between site operation and ZEHUA model predicted.

All conventional valve trays were replaced by ADV® valve trays for requirements of high separation efficiency and capacity. New-design downcomer technology and bubble promoters were used to increase open area in order to improve bubble status.

Result:

(1) When capacity was 150%, the operation results showed well and each process index could meet the requirements, even some specifications were superior to related requirements.

(2) When capacity was 150%, the average aldehyde and water contents for EO product were less than 15ppm and 95ppm, respectively. EO product was able to meet excellent grade of new national standard.

(3) When capacity was 150%, steam consumption per ton of product was deceased by more than 30%.