Methods for conserving the use of fresh wash water in crude oil desalting are described. A crude oil stream including salt mixes with a wash water stream to form an emulsion. The emulsion flows to a desalter, and the wash water coalesces to reform the wash water stream and to transfer at least a portion of the salt from the crude oil stream to the wash water stream. The crude oil stream with reduced salt content separates from the wash water stream. The effluent, which includes the wash water stream, flows from the desalter to a processing unit. The effluent is processed to reduce a concentration of salt in the effluent to be substantially equal to or less than a concentration of salt in the wash water stream. At least a portion of the processed effluent mixes with the crude oil stream before the emulsion flows to the desalter.

A process is described for reducing the total acid number of a refinery feedstock. A refinery feedstock containing naphthenic acids is contacted with an effective amount of solid catalyst that has been pretreated with an aqueous caustic base, for a period of time sufficient to neutralize at least a portion of the naphthenic acids in the feedstock. Thereafter, the aqueous phase is separated from the neutralized refinery feedstock.

The present invention describes a liquid-liquid extraction column with perforated plates and overflows, the plates also being equipped with an additional friction element which makes it possible to increase the thickness of the layer of coalesced matter and to guarantee a counter-current flow of the continuous and dispersed phases.

The systems and methods reduce the total acid number (TAN) in crude oil. The crude oil, that includes naphthenic acid, is mixed with at least a caustic solution (e.g., sodium hydroxide) to produce a mixture. After mixing, the mixture is pumped to an atomizing tank. The mixture is spray-atomized in the mixing tank to produce a condensed liquid state of the crude oil that settles at the bottom of the atomizer tank and to produce minute droplets (e.g. mist, fog or the like) of the caustic. The minute droplets interact with and neutralize the naphthenic acid in the condensed liquid state of the crude oil for a predefined period of time. As a result, the resulting crude oil in the bottom of the atomizer tank has a reduced TAN and includes salt water. Additionally, the resulting crude oil has a water concentration that does not exceed 0.5%.

A process for producing naphthenic base oils from low quality naphthenic crude feedstocks. The naphthenic base oils produced by the process have improved low temperature properties at high yields based on feedstock.

The invention relates to a hydrocarbon blend for input to a refinery and comprising a first blend component containing a renewable hydrocarbon component and a second blend component containing petroleum derived hydrocarbon to form at least part of a final hydrocarbon blend for processing in a refinery where the first blend component is characterized by comprising a hydrocarbon substance with at least 70% by weight having a boiling point above 220? C. and by having the characteristics (?.sub.d1, ?.sub.?1, ?.sub.h1)=(17-20, 6-12, 6-12) and; where the second blend component is characterised by having the characteristics (?.sub.{acute over (?)}2, ?.sub.?2, ?.sub.h2)=(17-20, 3-5, 4-7), where the first blend component is present in the final hydrocarbon blend in a relative amount of up to 80 wt %.

It has been discovered that contaminants such as metals and/or amines can be transferred from a hydrocarbon phase to a water phase in an emulsion breaking process by using a composition that contains water-soluble C5-C12 polyhydroxy carboxylic acids, ammonium salts thereof, alkali metal salts thereof, and mixtures of all of these. The composition may also optionally include a mineral acid to reduce the pH of the desalter wash water. The method permits transfer of metals and/or amines into the aqueous phase with little or no hydrocarbon phase under-carry into the aqueous phase. Resolving the emulsion into the hydrocarbon phase and the aqueous phase occurs in a refinery desalting process using electrostatic coalescence. The composition is particularly useful in treating crude oil emulsions, and in removing calcium and other metals therefrom. The polyhydroxy carboxylic acid additionally inhibits metal corrosion of metal pipe or other equipment used in a crude unit.

The invention relates to a method of characterization of one petroleum, wherein the petroleum is placed in contact with a metal part, and which includes the following steps: i. Modifying the water content (W) of the petroleum, ii. Measuring the corrosion (CR) of said metal part by the petroleum whose water content (W) has hence been modified, iii. Building, by reiterating several times the two previous steps (i, ii), a database containing a plurality of different values of water content (W) of the petroleum and a plurality of values of corrosion (CR) each corresponding to one of said values of water content (W), iv. Determining, by processing said database, an optimum value or an optimum range of values of water content (M.sub.W) of the petroleum for which the corrosion of the metal part shows a minimum value (M.sub.CR).

Problems of corrosion in the petroleum exploitation plants.

Processes for selective extraction of surface active naphthenic acids from high total acid number crude oils for use in enhanced oil recovery are provided.

A process for producing naphthenic base oils from low quality naphthenic crude feedstocks. The naphthenic base oils produced by the process have improved low temperature properties at high yields based on feedstock.