Antifoaming agent for delaying coking

Abstract

The invention relates to an antifoaming agent for delaying coking. The antifoaming agent comprises 10-35% of modified polysiloxane, 30-60% of long chain fatty alcohol and 20-50% of a solvent. The antifoaming agent is prepared through the following steps: mixing above components in proportion, stirring the above obtained system at 60-90DEG C for 1h, and cooling. The antifoaming agent has a low content of silicon of below 3%, is used for a coking delaying technology, can effectively inhibit and eliminate foams in a coke tower, and has the advantages of good antifoaming effect, small addition amount of 30-50ppm, wide sources of raw materials, and low cost.

Description

technical field [0001] The invention relates to a defoamer, in particular to a defoamer for delayed coking. Background technique [0002] Delayed coking process is a processing technology for converting residual oil into gas, gasoline, diesel oil, wax oil and coke through deep thermal cracking. It is an important means for processing residual oil in refineries and improving the yield of light oil. It is adaptable to different raw materials Strong, mature technology, but the raw material residue contains natural surfactants, which make the material in the coke tower produce a stable foam layer, which will have many adverse effects on the operation of the coke tower, such as: (1) The foam will The entrained material enters the pipeline before the fractionation tower, causing coking or even blockage in the pipeline, requiring regular decoking, which reduces the operating cycle; (2) The excessively high foam layer also occupies the effective space of the coke tower, resulting i...

AI Technical Summary

Problems solved by technology

[0002] The delayed coking process is a process for converting residue oil into gas, gasoline, diesel oil, wax oil and coke through deep thermal cracking. It is an important means to improve the yield of light oil. It has strong adaptability to different raw materials and mature technology, but the raw material residue contains natural surfactants, which make the materials in the coke tower produce a stable foam layer, which will cause the coke tower The operation has many adverse effects, such as: (1) The foam will entrain the material into the pipeline before the fractionation tower, causing coking or even blockage in the pipeline, requiring regular decoking, which reduces the operating cycle; (2) Excessive foam The layer also occupies the effective space of the coke tower, which reduces the utilization rate of the coke tower; (3) affects the yield of light oil; (4) the mechanical strength and electrical conductivity of coke decrease due to the existence of air bubbles

[0003]At present, the main means to solve the foam in industrial production is to add defoamer at the top of the coke tower. Most of the defoamers currently used are silicone defoamers, such as Silicone oil, its unique structure and properties make it widely used, but in practice, it is felt that the silicon-containing defoamer will bring harm to the downstream hydrofining process, such as silicon will be deposited on the refined catalyst, leading to catalyst deactivation and shortening catalyst life , and a large amount of precipitates will be produced during the hydrogenation process, resulting in short operating periods of the device and loss of catalysts. Therefore, people have done a lot of research work on reducing the silicon content of the defoamer and finding a substitute for the silicon-containing defoamer ,For example:

[0004]USP5,169,560 proposes to use sulfonate and phosphate compounds to replace silicon-containing compound defoamers; USP5,472,637 proposes to use polyisobutylene compounds to replace Silicon-containing compound defoamer; USP5,389,299 proposes to use animal oil instead of silicon-containing defoamer; USP4,961,840 proposes to use polysilazane mixed with inert gas to directly inject the foam to reduce the foam of the coke tower, and the injection method is from coke Injected at the top of the tower, the inert gas is used as an accompanying gas. Its function is to control the viscosity of polysilazane and prevent the injection port from being blocked, but it has little effect on reducing the silicon content.

[0005] Chinese patent CN1289819 reports a delayed coking process that reduces the coke tower foam layer, this method can eliminate a certain amount of foam in the coke, and can partially improve the utilization of the coke tower Compared with injecting silicon-containing defoamer in the whole operation cycle, the silicon content in coking distillate oil is greatly reduced. The disadvantage is that the efficiency is not high and the utilization rate of equipment is low; the patent CN101045880 proposes a 30-50% high molecular Block polyether, 20-40% fatty alcohol and 20-40% solvent composite additive, used to suppress the formation of foam in delayed coking coke towers, but the disadvantage is that the required amount of addition is large