A kind of high-acid heavy crude oil decalcification agent and preparation method thereof

Abstract

The invention discloses a decalcifying agent for high-acid heavy crude oil and a method for preparing the decalcifying agent. The decalcifying agent comprises, by weight, 15%-30% of chitosan modified by aminodithioformic acid, 20%-40% of quaternization salicyl chitosan Schiff base, 1%-5% of phase transfer agents and 30%-50% of water. The decalcifying agent and the method have the advantages that decalcifying agent compounds contain aminodithioformic acid groups and CN bonds, excellent chelating effects can be realized, and the decalcifying agent is excellent in decalcifying performance; the decalcifying agent compounds are chitosan derivatives and come from natural macromolecular substances, accordingly, the decalcifying agent is low in service cost and corrosion and good in biodegradability, and the problem of corrosion of atmospheric and vacuum electric desalting devices and equipment in refinery plants and difficulty in treating discharged sewage can be solved.

Description

Technical field: [0001] The invention relates to the field of crude oil pretreatment, and more specifically, to a decalcifying agent for high-acid heavy crude oil and a preparation method thereof. Background technique: [0002] In recent years, with the gradual deepening of crude oil extraction, both domestic and foreign crude oil has become very heavy and degraded. Correspondingly, the metal content in these heavy and inferior crude oils is also increasing. On the other hand, offshore crude oil is a high-acid heavy crude oil with extremely high metal content, especially calcium. Some crude oils have calcium content of more than 200 mg / L. The existence of these metal compounds, especially calcium salts, has serious harm to crude oil processing. [0003] Crude oil decalcifier is a refining aid that can effectively remove calcium and other metal impurities in crude oil. Crude oil decalcifiers are used in electric desalination units in oil refineries to form water-soluble compounds ...

AI Technical Summary

Problems solved by technology

[0004] Baker Hughes Corporation of the United States carried out earlier and more comprehensive research on crude oil decalcifiers. It mainly uses water-soluble hydroxycarboxylic acids and ammonium salts and alkali metal salts of these hydroxycarboxylic acids as decalcifiers. Calcium salts generate water-soluble chelates, such as CN102031142A, CN101081996, etc. This type of decalcifying agent has a good decalcification rate for crude oil with lower calcium content, but for crude oil with higher calcium content, only when the decalcifying agent and Only when the molar ratio of calcium ions in crude oil is above 5:1 will there be a better decalcification effect; at the same time, this type of decalcification agent is expensive, and due to the large amount of use, it leads to the discharge of sewage from the electric desalination unit of the refinery. COD increased significantly, and the processing difficulty increased

In China, Sinopec Petrochemical Science and Technology Research Institute is the research institute of crude oil decalcifier, which mainly uses acrylic acid series copolymers, sulfuric acid, organic phosphonates, etc. Among the decalcifying agents, acrylic acid series copolymers and sulfuric acid are organic strong acids or inorganic strong acids, which have a relatively serious corrosion effect on industrial equipment, and long-term use will affect the normal operation of the device

The use of phosphorus-containing decalcifiers such as organic phosphonic acid will also have a toxic effect on the catalysts of heavy oil hydrogenation and cracking processes downstream of the refinery.

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