Overview

Flare gas can have different origins and with it different approaches on how to handle them. The most common flows of flare gas are:

  • Oil gas flow: appears at oil exploration plants during oil extraction.
  • Nitrogen recovery flow: return flow of the nitrogen blanket gas stream which contains hydro carbons particles.
  • Emergency/Maintenance gas: collected during maintenance activities. Polluted by all sorts of hydrocarbons.
  • Mixed Off gas: is a mix of above flows from the refinery processes or others.

For each flow Gazpack has developed an approach that can help reduce or even stop flaring. Because of their different contents, each flow needs a different approach.

OIL GAS FLOW

Sulaway unit

Oil gas can be recovered depending on the composition of the gas. Mostly it contains components that can be extracted, only in some cases it might be so heavily polluted that recovery is not commercially interesting. Our Sulaway® system is developed to clean the gas and make it usable. 

NITROGEN RECOVERY FLOW

Nitrogen recovery gas has a similar composition to oil gas and can be recovered depending on the composition of the gas. Mostly it contains components that can be extracted, only in some cases it might be so heavily polluted that recovery is not commercially interesting. With the help of membranes or our Sulaway® package (in case of sulphur content) the nitrogen can be cleaned and recycled.

MAINTENANCE GAS

Since this gas is only 'produced' when maintenance is done it will not be a continuous flow and therefore not worthwhile economically to give a special treatment (flow scheme 4). For this purpose, a gas stack can be used which is a simple configuration of the flare. The stack needs to be purged to prevent rust forming which can hamper the functioning of the stack. In many cases methane gas is being used for purging but this is a large contributor to the greenhouse effect and should be prevented. A good alternative which is very environmentally friendly is high purity nitrogen gas. It does not only prevent rust but the oxygen content in the nitrogen also enhances the flammability of the maintenance gas when it is burnt in the gas stack. Gazpack can deliver a small nitrogen generator to produce the required nitrogen for this application. 

MIXED OFF GAS

Quencher

Mixed off gas is often heavily polluted with all sorts of hydrocarbons and high contents of sulphur. Heavy hydrocarbons are difficult to separate and therefore transforming this gas into a usable product is not feasible. However, the sulphur inside the gas can be transformed into acid water with our Gazpack Quencher. The water needed for the transformation can be used from equipment water drains recycling the outgoing streams. On platforms, where water is not easily available, sweet water can be generated from seawater with special membranes. Acid water can be sold for the use in batteries (if not polluted with other components) or it can be diluted and released into the sea (according to Marpol Annex VI resolution MEPC 184(59) 1 kg/s = 14 ton seawater per hour). Another option is to inject this into an old oil well.

Advantages:

  • A usable product is generated with low volume which is interesting for transportation (i.e. 5000 Nm3/h sour gas with 0,5 % H2S will be quenched down until 3 m3 acid water containing SO2).
  • The process is environmentally friendly since all polluting components are captured and Sulphur is transformed into a harmless component or usable product.
  • Heat can be recovered from the process that can be used in other systems (i.e. for heating of air).