Northey have extensive experience working closely with a number of Oil majors, and smaller up and downstream companies. We work both onshore and offshore, specialising in sour gas, vent gas recovery, and solving difficult process problems.

Northey Technologies Ltd has built up, over many years, a reputation for reliability and workmanship that is pivotal to a successful partnership offshore. With the ever-increasing cost of downtime, the use of Northey equipment has enabled our customers to plan life cycle costs and maintenance schedules with confidence.

 

The systems were first developed for offshore gas production platforms but they can be adapted for any application where gas is flared or vented to the environment.

Many of the existing gas production platforms produce wet gas. In some cases this is pumped ashore directly, in others it is dried before being transferred on shore to reduce corrosion in the pipeline.

Drying is usually done using Tri Ethylene Glycol (TEG) which is then recovered by distillation.

There is a problem with the distillation process because there is an emission to the environment of a certain amount of vapours. These vapours contain Natural Gas, BTEX, water and inerts (Nitrogen, Carbon dioxide), which under current legislation should not be discharged to the environment.

The vent gas from the Still Vapour Condenser is released at a temperature of approximately 40oC and is saturated. The condensate formed is drained to a holding tank. In this tank the Hydro Carbon phase and the Water phase are separated and brought via separate lines to the sump.

The vapour is extracted via the existing LP vent line. This line contains a number of bends which collect condensed liquids and prevent liquid entrainment. This vent line is continuously drained to the holding tank. In order to remove the maximum of condensates the gas is compressed and then cooled using a shell and tube aftercooler. Further cooling is achieved using a refrigerated chiller system and droplets of condensate are removed in a separator. The processed gas is then reheated using the incoming gas stream to reduce the dew point and prevent any further condensation in the process line.

Installation of these systems is necessary to ensure that the operator complies with the latest environmental legislation regarding emissions from offshore platforms and avoids penalties.

The added benefit is that the waste gas is maximised to aid the Glycol Generator and service local burners and generators.

Due to their stand alone function the skids can be installed and commissioned with little or no process down time.

Northey Technologies will design and build these systems as “plug and play” units and provide installation and commissioning.