Part of refinery complex

Fouling inhibitors provide extended runtimes and energy savings.

Fouling is a serious problem at oil refineries. It may lead to insecure operating conditions with high production losses. Shortened runtime is a drawback, which requires cleaning procedures. In some cases, a material exchange could be necessary. Mechanical designs, process conditions and feed qualities influence the fouling potential and operation. Typical fouling components are waxes, asphaltenes, carbon deposits, stable emulsions, inorganic solids or polymers. In oil refineries, most organic fouling is caused by asphaltene precipitation, including coke formation. Asphaltenes are sensitive to shearing forces and electrostatic interactions. Crude preheat trains, vacuum column bottoms and downstream heat exchangers can plug. The economic implications are significant and can cost millions of dollars.

The best strategy to avoid asphaltene precipitation is the stabilization of asphaltenes. Kurita´s asphaltene dispersants keep the particles small avoiding agglomeration. They work by surrounding the asphaltene molecules, similar to the natural resins in crude oil. This keeps the hydrocarbons in a colloidal system. The asphaltenes stay in a disperse phase why asphaltene precipitation is prevented.

Gasification with partial oxidation (POX) is an old technology. The process has been developed for over 200 years. It is far older than modern oil refineries for the production of fuel oils. Gasification is an exothermic, non-catalytic reaction of the feedstock and limited amount of oxygen. In a highly reducing atmosphere hydrocarbons are converted into electric power, synthesis gas, fuels, fertilizers and chemicals. The produced raw gas has a temperature of about 1300 – 1400°C. Severe fouling of the syngas cooler because of carbon deposits may result in an unwanted shutdown. Under such process conditions commonly used antifoulants will decompose at once with no effect. Kurita developed an antifoulant technology for the POX process. This fuel additive has an excellent thermal stability and reduces carbon deposits. It minimises the fouling potential in the waste heat reboilers by softening the deposits. This keeps the coke particles small to be transported with the syngas.

In oil refineries, small amounts of oxygen can cause or accelerate polymerisation. Our antioxidants terminate the peroxide radicals which are formed when oxygen reacts with hydrocarbons. This prevents gum formation derived from thermal and catalytic cracking operations. The antioxidants act as chain-stoppers and stop the initiation or propagation reactions of the radical reaction process. Kurita provides a complete range of programmes consisting of dispersants, oxygen scavengers, stabilizers, antioxidants and metal deactivators.

Kurita adapts the treatment concepts to your needs to prevent fouling and operational limitations. Our fouling inhibitors have a good thermal stability. They can be used as well at higher temperatures, where precipitation, polymerisation or coke formation would occur.

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