Improved Process Integration and Waste Heat Utilisation at Akzo Nobel´s Revamped Amines Plant

Abstract

The Akso Nobel amine plant in Stenungsund has recently undergone a debottelenecking retrofit project to increase throughput by 10%. Suggestions in previous heat integration studies have been partly implemented, process streams have changed after every retrofit. In this Master´s thesis, the aim is to investigate and analyse from the energy point of view, the most recent retrofit proje´ct on the amine production site. The basis of this study is the process energy demand before and after revamp and the plant is studied using pinch technology. The potential savings of the amine plant after retrofit has increased from about 10% to 15%. One heat source is identified for internal heat recovery of a maximum 3MW. Suggestion for improvement involves internal heat recovery in the process by installing two heat exchangers with a total of 2.376 MW. The cost of improvement is estimated to be about 1.7 MSEK with a payback period of 0.317 year. The extensive indirect heat transfer through the circulating water system is acceptable from energy efficiency of view. There is a potential for heat pumping. Further study is required. Large amounts of true waste heat are available despite of limited consumer demand.