Multistage Ejectors for Flare Gas Recovery

Lead Research Organisation: University of Nottingham
Department Name: Faculty of Engineering


The project focuses on the development of a multistage ejector for use in flare gas recovery in the oil and gas industry.
Significant levels of flare gas is released in the extraction of oil and gas. This was equivalent of 140 billion metres cube in
2011. The adoption of flare gas recovery units is dependent on a financial return as there is as yet no international
convention of flare gas emission currently enforecd. This project will explore the feasibility of using a two stage ejector
based system to compress the flare gas to a useful pressure rather than "flaring" it off. The current difficulties with this
proposed system are: i) at elevated waste gas inlet pressure to the second stage ejector, currently at elevated suction
pressure the efficiency of the ejector is reduced significantly. ii) multistage ejector systems rely on phase separation
between stages, Transvac currently does not possess the necessary information on optimal separation technology for this
application. If these issues could be overcome then the multistage system would represent a significant reduction in both
the cost of flare gas recovery system installation and operation, making the process more feasible for installation.

Planned Impact

Economy: The proposed development would lead to Product security, Wealth generation and investment, and generation
of employment.
Environment: Reducing the flare gas would contribute to minimizing the CO2 output. This will provide means to meeting the
CO2 reduction targets.
People: New product development proposed here would lead to new skills improving the employability of people.
Society: The end result would see contributions towards improvement of life standards by improving the gas recovery and
improving the air quality through minimal flaring.


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Description The task is to work with a company that intend to develop a multi stage ejector compressor system to recover flare gas. As the academic partners, we have developed a design tool to select the optimal phase separator for any given ejector configuration. This tool provides dimensions of the equipment and the pressure drop across it.
Exploitation Route This software application is not limited to ejectors. It could be used to size phase separators for any industrial process where liquid has to be separated from its vapour (Eg. distillation reflux drum, oil and gas primary separators). This could be used by chemical plant design companies as a tool.
Sectors Agriculture, Food and Drink,Chemicals,Energy

Description The socio-economic benefits of this project is threefold. The grant enabled us to investigate what was considered as conventional technology in a different light that lead to considerable improvement to capture the interest of the industries. This has led to a considerable increase in company's revenue contributing to the growth of the economy of the country. The increased sales has generated several employment opportunities for the locals providing transferable skills and technology training. This has and would improve the local economy and reduce social problems due to unemployment. The technology developed during this project is in an increasing trend of being applied to reduce flare gas in relevant industries reducing their CO2 emissions improving local air quality; hence the quality of life in local communities. Further it addresses the global environmental problems to certain extent making an impact.
First Year Of Impact 2016
Sector Energy,Manufacturing, including Industrial Biotechology
Impact Types Societal,Economic

Description Multistage Ejectors 
Organisation Transvac Systems Ltd
Country United Kingdom 
Sector Private 
PI Contribution This is a collaboration to develop multistage ejector compressor for flare gas recovery. Transvac Systems Ltd has expertise on ejector systems. our contribution is in developing the two-phase separators that would minimize the area requirement. Further to this, we provide multiphase flow expertise in measurements and modelling.
Collaborator Contribution Partners have provide us access to design data as well as the high pressure two phase flow loop on their cite.
Impact Internal technical report on separator selection and design has been produced. Furthermore a software has been developed to design phase separators.
Start Year 2015
Title Gas-Liquid Phase Separator Design Software 
Description Software takes flowrates as inputs and produce optimized design parameters. It computes design data for phase separator cascades too. 
Type Of Technology Software 
Year Produced 2016 
Impact This is a software developed as a part of the InnovateUK grant and the software has been given to industrial partner. The software has not been made available widely at this moment.