Gas Ejectors for Flare Recovery

Flare gases are a combination of raw natural gas, vapours generated from crude oil tanks and other gas generated during oil & gas production and refining. Traditionally these gases were typically burnt in flare stacks.
But in the past decade Oil & gas producers and Refiners have begin to realise the disadvantages of burning flare gas. The disadvantages being
• Loss of fuel rich gas
It is estimated that 140 bcm (billion cubic meters) of gas is flared annually. In an ideal scenario if this is recovered it can be used to generate almost 8 GW Electric power enough to power multiple cities throughout the year
• Air, Heat and Light pollution
It is estimated that flaring has resulted in Green house gas (GHG) emissions equivalent to 500 Mt of CO2 annually. To put into perspective it will take 20000 Trees to absorb the generated emissions

Considering that many countries have set a goal to become a Net-Zero Carbon Emitter in the 2nd half of the 21st Century, multiple regulators bodies are coming up with regulations discouraging flaring.

But recovery of Flare gases is not an easy task and fraught with below challenges
• Availability at low Pressure
Generated flare gases are typically at atmospheric pressures and need to be compressed in order to reuse them in the plant’s fuel gas network
• Sour Service
Flared gas tends to have high concentrations of H2S. H2S possess a risk to the plant infrastructure and hence needs to be separated or neutralized during recovery

Gas Ejectors operate on the basis of jet Venturi principle and utilize energy in compressed fuel gas for their operation. During operation the gas Ejector displays a special ability to create vacuum at its inlet and at the same time creating a compressive effect between its inlet and outlet.
This enables the gas Ejector to utilize the vacuum to suck flare gases from the flare gas header and then compress it to the required pressure. The compressed flare gas can be reinjected into the fuel gas grid after appropriate treatment.

Gas Ejectors are suited for Flare Gas Recovery due to their inherent characteristics
• The flare gas generation in Each Oil & Gas facility varies drastically. Gas Ejectors can be easily customized and hence are designed as per each facility.
• Can be manufactured in materials compatible with the sour service requirements.
• Gas ejectors do not contain any moving parts and have large internal passage areas, hence are not vulnerable to liquid entry or clogging by solid particles.
• As they have no moving parts, maintenance requirements are very less. Also it reduces largely the risk of abrupt breakdowns, helps in maintaining the regular production schedule
• Fuel gas is a available at high pressures in all Oil & Gas Facility and hence no additional infrastructure is typically required.