Crude oil flowing from wells contain fair amount (often 20-30%, sometimes up to 60-65%) of water with dissolved salts from basis point up to 1-2%. This significantly increases viscosity of crude oil, generates stable emulsion and makes the oil inadequate for refining and transportation. Water produced together with oil is usually in very unusual state, i.e. it is spread in oil in the form of droplets (emulsified form). Less the size of droplets, more stable the emulsion. One of the main reasons of emulsion stability is also the presence of resin, pyrobitumеn, paraffin, and other oil admixtures like glycerine, microcrystal of paraffin, ceresin in crude oil. These substances generate quite firm and thick (protective films) on the surface of water and solid particles thus preventing merging of water drops and solid particles and their spontaneous segregation from oil.
At present physical, thermal, physicochemical, electrical and combined methods of oil emulsion breaking are used for oil dehydration and oil desalting.
One of the widelyused and most effective methods is physicochemical combined method using chemical reagents demulsifiers.
Demulsifiers are substances with high surface activity. They are concentrated in interfacial areas of oil emulsion, break protective films covering solid particles, water droplets and neutralise their electric charges. After this, small droplets will merge into bigger drops under the influence of mutual attraction, loosen and segregated from oil.
Oil dcmulsifying is carried out in oil field and oil refinery plants.
Oil usually is not completely dehydrated and desalted in field demulsifying plants and residual water content often equals to 1 -2%, salt content 70-150 ml/1. Therefore oil undergoes secondary demulsification and additional desalting in refinery.
Residual water and salt complicate oil refining. Large amount of generated water vapours interrupt distillation process and chloride salts of calcium, especially manganese produce free salt acid, corrode metallic parts of equipment, sediments on heat-exchanging units, capacitors, oven pipes, interrupts operation process, reduces remedial work period.
A lot of demulsifiers for oil dehydration and desalting were produced, but each of them has several shortages, related to considerable expense of demulsifiers, low efficiency, toxicity, and mainly expensive price.
In order to improve efficiency of oil dehydration and desalting processes, “KARVAN-L” company has produced local natural ecologically clean crude based demulsifiers. Reagents exhibiting necessary set of properties for relevant application comditions are selected on their basis using blending or chemical modification method. Process impact efficiency of produced demulsifiers is provision of fast and complete segregation of water and salts at minimum reagent discharge.
At present “KARVAN-L” company tries to provide integrated work cycle: – development production supply and implementation of produced demulsifiers together with consumer.
Demulsifier Karvan-200 is designed for oil dehydration and desalting in gathering system and oil treatment plant. Reagent can also inhibit corrosion processes.