Waste Heat Recovery in Gas Processing by Organic Rankine Cycle

Abstract

ADNOC Gas Processing is looking into the energy saving opportunities to improve plants energy performance, aiming continual improvement and also for sustaining the already achieved efficiency improvement in varying operating scenarios. It is in line with the ADNOC Sustainability Strategy target for the Year 2030 which requires reducing the Green House Gases (GHG) intensity by 25% in Year 2030 considering Year 2018 as the baseline. Therefore, multiple avenues and opportunities were looked into to contribute towards this ambitious target. One of the promising contributors, having substantial potential of energy savings, is the Waste Heat Recovery. In this context, ADNOC Gas Processing has evaluated the option of utilizing waste heat from different heat sources across different plants using the Organic Rankine Cycle to generate power. Waste heat sources like exhaust gases from power generators, mechanical drive gas turbines, heaters and incinerators stacks, and low pressure steam condensers have been assessed. This opportunity of waste heat recovery exhibits substantial potential to contribute towards GHG emissions intensity reduction, reduce power import, improve energy efficiency and reduce the operating costs. The paper presents the techno-economic appraisal of the opportunity for the selected waste heat sources.

Opportunities of waste heat recovery from various sources: Review of technologies and implementation

“…The rising interest in CHP systems is hinged on their ability to offer a cost-effective means of reducing GHG emissions, in addition to their higher flexibility compared to other power generation systems such as single Joule or Rankine Cycles [ 116 , 117 ]. The installation of HRSGs for the recovery of the WH from a gas turbine exhaust gas to generate superheated steam is viable economically with a high return on investment and attractive financial indicators [ 118 ]. The major disadvantage of CHP system is large investment costs as the following are required in its setup: (i) Space for the CHP energy centre (ii) A large diameter-heavily insulated metal piping (iii) Costs to administer and sustain the energy centre throughout the life of the equipment, etc.…”