Reducing costs for clients, inspiring public confidence and protecting the environment all in one solution.
The Problem
Gas flaring is a safe and effective way of disposing gases associated with drilling for crude oil. It is also considered a major environmental problem. Every year around 150 billion cubic metres of natural gas is being wasted by flaring. Not only is it a waste of resources but the rise of environmental pressures and standards in recent years has caused Oil & Gas companies to seriously consider ways to reduce their carbon footprint on the environment. The World Bank's Global Gas Flaring Reduction public-private partnership (GGFR) estimates that at least 400 million tons of CO2 are released annually due to oil and gas flaring alone.
Another environmental problem is vapour release after processes such as TEG distillation. These vapours are often not flared but contain gasses that should not be discharged into the environment and doing so is also a waste of resources.
Managing environmental requirements can be costly both in time and money but are becoming more and more essential every year. There is a need to find other uses for these gases and the infrastructure for these uses, rather than flaring. The reduction of gas flaring and vent emissions will greatly contribute to increasing energy efficiency and sustainable development in the oil and gas industry.
The Solution
Vent Gas Recovery Systems (VGRS) designed by Northey Technologies , combine the highest levels of reliability and durability with an oil free lubrication system, offer the ideal solution by converting gases previously vented into the atmosphere into a reusable resource, whilst removing harmful contaminants. This helps to reduce overall costs, increase profits and protect the environment. The system recovers pollutants from vent gas and returns the gas for use as fuel and for stripping. This has been achieved through chilling the gas to condense the water and HC's, and then reheating it - providing a clean source of natural gas with a dew point of 5°C.The systems were first developed for offshore gas production platforms but they now can be adapted for any application where gas is flared or vented to the environment.
The Northey Compressor has now been successfully installed in 5 platforms in the North Sea. The VGRS is solely distributed in Australia by Dynapumps. Due to its unique design and fabrication these systems come as “plug and play” systems, which further reduce costs as there is little to no process down time. Spare parts and servicing can be organised locally through the after sales team at Dynapumps.
How it works
Unlike many alternatives these compressors are not lubricated with oil and so gas pollution is avoided. The Northey Compressor is designed to recover vapours such as natural gas, BTEX, water and inerts (nitrogen, carbon dioxide) from TEG (tri ethylene glycol) boilers and distillers which are the main pollutants of gas flaring and vent emissions.
The vapour is extracted via an existing LP vent line, which is continuously drained to a holding tank. The line contains a number of bends which collect condensed liquid and prevent liquid entrainment. To remove the condensates, the gas is compressed, then cooled using a shell and tube after-cooler, and cooled further by a refrigerated chiller system, while droplets 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. Although a complex process, it ensures that operators are in line with environmental legislation.
Northey are also currently supplying a system to handle the off gas, saturated with water at 80 deg celcius resulting from the extraction of heavy oil from oilfields using steam.
Jim Ellery, General Manager, Dynapumps says, “It’s exciting to see such innovative and forward thinking technology available now in Australia. This system is truly beneficial to both our clients and the environment as it increases efficiency and leaves a really positive outcome for the environment.”