On fighting toxic gases

Hydrogen sulphide or H₂S, is a colourless, toxic, flammable gas with a particularly unpleasant odour of rotten eggs. It often results when bacteria break down organic matter in the absence of oxygen, such as in swamps, and sewers. It also occurs in volcanic gases, natural gas and some well waters.

Why remove H₂S?

H₂S is recognized as a serious health hazard.  Long-term low-level exposure can produce a number of  chronic ailments; high-level exposure can be fatal.  H₂S is also highly corrosive when it comes into contact with metals and concrete, resulting in considerable maintenance and replacement costs.

Where is H₂S a problem?

H₂S is also often found in the water treatment industry where it is can be a serious health hazard.  A bad odor is typically the first sign of septic wastewater, but at higher levels, paralysis of the lungs occurs, which can result in fatal accidents, several of which occur annually in Europe.

As well as being dangerous to health H₂S is also corrosive, resulting in considerable cost implications.  By reducing H₂S corrosion in pumping stations, sewer networks and the like maintenance and capital investment costs can be reduced significantly.

Hydrogen sulphide is found in oil and gas reservoirs where souring of the fuel can be caused by Sulphate Reducing Bacteria (SRB). Fuel that is high in sulphates costs more to refine and, therefore, commands lower prices in the market. Reservoir souring and controlling hydrogen sulphide production has traditionally been an expensive problem both to treat and prevent.

How does Yara deal with this toxic gas?

Yara produces two separate but equally important products for use in the water treatment and oil & gas industries. 

The first, Nutriox, is used to eliminate and prevent the formation of hydrogen sulphide in all waste and water management plants and installations. It is a natural biological method of preventing septicity and eliminating and preventing H₂S through the controlled dosage of nitrates. The Nutriox treatment technology is well established in both Europe and North America, and customers range from municipalities to water treatment companies.

PetroCare is a family of nitrate-based products created especially for the oilfield market. They work on a similar principle to Nutriox, preventing the formation of hydrogen sulphide, though in this instance in oil reservoir installations. PetroCare products are also used to boost oil production from natural reservoirs and increase the lifetime of oil fields. It is already used extensively in the North Sea as well as in the Gulf of Mexico. The PetroCare products are regarded as being environmentally friendly. They appear on the list of chemicals regarded under The Convention for the Protection of the Marine Environment of the North-East Atlantic (OSPAR Convention) as Posing Little or No Risk to the Environment (PLONAR).