Energy Recovery Systems in Acid Gas Recovery Plants


Authors (Energy Recovery): Chinmay Deshpande, Matthew Pattom, Dung Tran
Authors (Saudi Aramco): Rehan Farooqi, Mohammad Buali, Abdullalh A. Al-Ghamdi

Four sets of hydraulic turbocharger based energy recovery systems (2000 hp each) were successfully designed, manufactured, tested and commissioned for Acid Gas Recovery plants (AGR) in Saudi Arabia. The hydraulic turbocharger consists of a liquid phase turbine runner and a pump impeller mounted in a back‐to‐back configuration on a common rigid shaft, in a single seal‐less casing. The shaft is supported by process lubricated hydrodynamic radial and axial (dual‐acting) bearings of non‐metallic construction. The turbine side extracts wasted pressure energy from the rich amine and along with a series of throttle, auxiliary and bypass valves, controls the level in the absorber. The pump side boosts the lean amine solvent to the absorber. Such a design provides major advantages compared to a conventional configuration of a reverse running pump‐as‐turbine coupled to a pump. These advantages include a compact single stage hydraulic design (as opposed to a multi‐stage design for a reverse running pump), smaller footprint, higher efficiency, absence of mechanical seals & associated support system, absence of lubrication oil system as well as simpler control.

Several complex design and testing challenges were overcome through development of novel design features and incorporation of provisions in a highly specialized test loop. Some of the unique experiences are shared in the paper. The seal‐less design of the turbocharger with no exposed rotating or bearing parts presented testing challenges such as determination of shaft power, individual pump side and turbine side performance and efficiencies; measurement and validation of axial thrust & axial position; as well as monitoring & control of bearing performance parameters. The test loop was engineered to operate the hydraulic turbocharger through its testable operating range with provisions to measure, control and monitor all the needed parameters. Testing was performed using water with viscosity 2.5 times lower than the operating fluid. This implied suitable modification to the design, monitoring and controlling of process‐lubricated bearings along with the internal system during testing to account for the change in viscosity. Data was evaluated to conduct root cause analysis of apparent bearing failures such as rub marks and to eliminate root causes by improving the manufacturing method to reduce misalignment & also using non‐metallic bearings.

Four identical units were built and completed successful Factory Acceptance Tests (FAT) in early 2018. The turbochargers achieved & surpassed the pump side rated requirements of 2148ft of head at 2820 gpm, at a rated speed of 8000 rpm, as part of the FAT. All the units were installed & commissioned in early 2020 by the End User. Each unit is part of 4×50 configuration – which includes the turbocharger and three circulation pumps running in parallel. The paper will provide details about the commissioning effort of the turbocharger units in the field, and their operating experience over a period of one year.

IsoBoost for Gas Processing and Ammonia

IsoBoost is a hydraulic pumping system that saves energy in acid gas removal and CO2 removal processes in ammonia production and gas processing. This video covers the basics of how the Energy Recovery IsoBoost system works, and the benefits it can offer operators.

Optimizing Amine Process Design Using Liquid-Phase Turbochargers


Acid gas removal is a critical process step in natural gas processing and syngas production for ammonia and other uses. Application of a liquid phase turbocharger to the acid gas removal unit (AGRU) results in significant energy savings and improvement to reliability, availability and maintainability (RAM) of the plant. This paper describes conventional configurations with high-pressure pumps and new configurations utilizing liquid-phase turbochargers. Design of the equipment, process operations and controls, and reliability analysis are included. The results of a RAM study comparing conventional configurations to those incorporating liquid-phase turbochargers in multiple cases are also presented. From the RAM study, it can be concluded that flow sheet configurations that include a liquid phase turbocharger consistently provide lower plant downtime and maintenance costs as compared with conventional flow sheet configurations. This is in addition to the energy savings that result from energy recovery with the application of the liquid phase turbocharger to the AGRU. For the reference plant used in the study, the maintenance cost savings are as great as $2.5M over the 20 year lifetime of the plant and average annual downtime reduction is as much as 19.8 hours.

IsoBoost for Gas Processing Overview

This video animation describes the IsoBoost™ hydraulic system for gas processing. The skid-mounted solution recovers pressure energy at gas plants and ensures reliable operations, making plants safer and more profitable, with three times the life of a conventional pump.

GP Turbo Overview

This video shows how the GP Turbo works. The GP Turbo is the turbocharger at the heart of Energy Recovery’s IsoBoost system. IsoBoost is a hydraulic system that recovers pressure energy for gas processing. It provides reliable operations for gas processing, making plants safer and more profitable, with three times the life of a conventional pump.

Plug and Play: Installation Time Lapse

This time lapse video shows a typical shipment and installation of Energy Recovery’s Oil & Gas skid-mounted systems. This particular unit was installed in a Louisiana processing plant.


Durante el siglo pasado, la práctica del reciclaje de energía ha sido incluida en diferentes procesos industriales como un paso clave para minimizar lo que de otro modo sería energía desperdiciada. La mayoría de las industrias están familiarizadas con el concepto de recuperación de calor residual, donde el calor que habría sido disipado y desechado, es devuelto a los diferentes procesos industriales. La recuperación de calor residual ha ayudado a la industria a optimizar sus eficiencias y así aprovechar las oportunidades para volverse más rentables. Pero muchas industrias, incluyendo la del procesamiento del gas natural, aún pueden aplicar otros métodos de reciclaje de energía para obtener otro recurso de energía: la energía de la presión residual.

IsoBoost Brochure

Download our IsoBoost brochure, covering the features and benefits of our hydraulic pumping system. IsoBoost saves energy and improves reliability in both CO2 removal in ammonia production and acid gas removal in gas processing.

Improved efficiency and lifetime reliability with new hydraulic energy recovery design for CO2 removal

The CO2 removal process in ammonia production is a significant contributor to overall plant energy consumption. The bulk of the energy is used for regeneration of the rich solution, but an appreciable part is electric energy for pumping of the semi-lean solvent. Historically, hydraulic power recovery turbines, in the form of reverse running pumps, have been utilized as an energy recovery device in this application. This paper presents a new turbocharger-based solution. The use of a liquid-phase turbocharger offers simplified design, compact footprint, rapid install, and increased plant uptime with high efficiency across a wide range of operating conditions.

When pressure energy becomes a reliable energy resource featuring the IsoBoost technology

Today, energy costs represent one half of the total cost of oil & gas processing. By harnessing the wasted energy in your high-pressure environment, we can help you slash that cost by 25%, while significantly lowering your carbon footprint. And we have proof. Read all about it in this free white paper available for download now.

Six years ago, we installed our energy-saving IsoBoost Technology at the 50 million cubic-foot-a-day Jackalope Amine Gas Processing Plant in Hebronville, Texas. Since then, our solution has:

  • Ran for six straight years, requiring virtually no maintenance
  • Reduced emissions at the plant a total of 14.4 million pounds of CO₂
  • Saved the small plant $155,000/year, or close to a $1 million in power savings.

Don’t waste another year’s worth of profits. Discover how Energy Recovery can help you today!