Kurita provides tailored treatment concepts for refinery applications

Hydrogen sulfide and mercaptan scavengers.

Hydrogen sulfide (H2S) is a naturally occurring gas obtained in many crude oils. By degradation of sulfur compounds in the oil additional hydrogen sulfide can be released. That mainly happens when sulfur compounds come in contact with water at high temperatures. Hydrogen sulfide is a toxic, colourless gas with a rotten egg odour. It is detectable a low ppb level and may be present in all refinery process streams. Mercaptans (RSH) are a common contaminant of lighter hydrocarbon components. They are less reactive than hydrogen sulfide but limit the product specifications as well. Both contaminants are corrosive to metals, can poison catalysts and are very offensive smelling.

At high temperatures, bitumen (asphalt) as the heaviest refinery product can release larger concentrations of H2S to the vapour phase. During plant shutdowns, tanks, containers and distillation columns must be opened to allow necessary on-site inspections. The concentration of H2S in the headspace of storage tanks can change because of temperature, agitation, viscosity and tank level. Hydrogen sulfide and mercaptan compounds need to be safely removed prior to any entry and inspection.

Hydrogen sulfide presents significant safety, operational, environmental and compliance issues. To meet specifications and safety requirements, hydrogen sulfide removal from refinery gas, distillates and fuels is necessary. The use of a hydrogen sulfide scavenger is necessary to lower the risks. Commercial neutralising amines are often used as H2S scavenger products, but they are not selective for hydrogen sulfide removal. At high temperature, such H2S scavenger products have reversible properties and will release the H2S again. Requirements for a good H2S scavenger are preferably oil-soluble additives, rapid and non-reversible reactions and high thermal stability.

Increased concentrations of hydrogen sulfide or mercaptans in end products reduce their quality significantly. These "low-quality" end products have to be sold at a lower price. In the worst case, they need to be reused in refinery processes. However, it means a loss of production why a high-performing H2S scavenger can be the first choice for the hydrogen sulfide removal. Kurita‘s hydrogen sulfide scavenger programmes eliminate these inconvenient components. For the removal of mercaptans very efficient chemical programmes are also available.

Our H2S scavenger products provide a rapid reaction with minimal mixing by increasing the quality and the value of the finished products. Our treatment programmes rapidly remove hydrogen sulfides and mercaptans in the product streams.

Kurita´s tailored hydrogen sulfide scavenger products allow a safe and timely inspection of the systems. The very low dosing rates and cost-effective treatment provide significant benefits for you in a variety of products. According to your specifications, Kurita will supply metal-free H2S scavenger technologies which are completely soluble in oil or water with good anticorrosion properties. Our hydrogen sulfide scavenger products have a high thermal stability. If required, Kurita can supply non-nitrogen containing hydrogen sulfide scavenger versions.

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