CN109762601B

CN109762601B - Coke inhibitor

Info

Publication number: CN109762601B
Application number: CN201910201223.7A
Authority: CN
Inventors: 王洪雷; 郭钢福
Original assignee: Inner Mongolia Dajiang Runye Environmental Protection Technology Co ltd
Current assignee: Hubei Dajiang runye renewable resources Co.,Ltd.
Priority date: 2019-03-15
Filing date: 2019-03-15
Publication date: 2021-01-22
Anticipated expiration: 2039-03-15
Also published as: CN109762601A

Abstract

The invention provides a coke inhibitor capable of delaying coking of a furnace tube, a filler and a heat exchanger in a waste oil distillation process and effectively prolonging a start-up period, which makes full use of the coke inhibitor to soften coke blocks, inhibit condensation and polymerization of condensed aromatic hydrocarbon and prevent or reduce formation of coked substances, and effectively reduces acid corrosion of acid value control equipment after the product is added in the waste oil atmospheric and vacuum distillation process; the coking speed is greatly reduced, the start-up period is prolonged, the maintenance once per month is prolonged to the maintenance once in three months, the production days are increased, and the maintenance cost investment is reduced to bring direct economic benefits to factories.

Description

Coke inhibitor

Technical Field

The invention relates to the technical field of waste oil regeneration, in particular to a coking inhibitor capable of delaying coking of a furnace tube, a filler and a heat exchanger in a waste oil distillation process and effectively prolonging a start-up period.

Background

Delayed coking is used as a deep processing technology of residual oil and plays an important role in the oil refining industry of China. As crude oil in the world gets heavier and worse, petroleum processing conditions become more severe and the problem of coking of refinery equipment and pipelines becomes more prominent. In the field of waste oil regeneration, the problem that the shutdown and maintenance are necessary because the pressure is increased and finally the heat exchanger is blocked due to coking at furnace tubes, fillers, heat exchangers and other parts cannot be avoided by using an atmospheric and vacuum distillation process at present. In particular, the deterioration of raw oil of a delayed coking device causes the heating furnace tube to be easy to coke, the heat efficiency of the heating furnace is reduced, and sometimes, the pipeline is blocked, so that the operation period of the device is shortened, the potential safety hazard is brought to the device, and the normal production of the device is seriously influenced.

Nearly all domestic atmospheric and vacuum factories have a start-up period of about one month, frequent maintenance affects normal production, the total annual production days are reduced, and the maintenance process is expensive. And the industry has little means to combat this problem.

Researchers at home and abroad began to pay attention to the coking problem in the petroleum refining process from 50 years and researched the coking mechanism. At present, a chemical method is generally adopted, and a certain amount of chemical substances are added into raw oil to be used as a coking inhibitor to inhibit coking.

Disclosure of Invention

The invention aims to provide a chemical coke inhibitor which is fully utilized to soften coke blocks, inhibit condensation and polymerization of condensed aromatic hydrocarbon and prevent or reduce coke formation.

The invention provides a chemical coke inhibitor, which comprises potassium hydroxide, magnesium oxide, sodium dodecyl benzene sulfonate, phosphorus diphenoxy and dodecyl sulfopropyl betaine.

The mass ratio of the components is 50-80:10-30:5-15:10-20: 2-5.

The preparation method of the anti-coking agent provided by the invention is to mix the components together according to the proportion.

The coke inhibitor is used in 2-3 kg/ton waste oil (clean oil).

The invention also provides a using method of the coking inhibitor, which comprises the steps of adding 3-4 times of water into the coking inhibitor, fully stirring the mixture into turbid liquid, pumping the turbid liquid into an oil tank, uniformly stirring the turbid liquid, and feeding waste oil in the tank into a distillation section.

The invention also provides a method for delaying coking of a furnace tube, a filler and a heat exchanger in the waste oil distillation process, wherein the chemical coke inhibitor provided by the invention is injected into the raw materials before distillation in proportion, and after the raw materials are uniformly stirred in the stirring tank, the raw materials are normally fed and are sent to a distillation tower through a pump.

The invention has the beneficial effects that:

the invention provides a chemical coke inhibitor, which makes full use of the chemical coke inhibitor to soften coke blocks, inhibit condensation and polymerization of condensed aromatic hydrocarbon and prevent or reduce the formation of coked substances, and effectively reduces the acid corrosion of acid value control equipment after waste oil is added into the product in the atmospheric and vacuum distillation process; the coking speed is greatly reduced, the start-up period is prolonged, the maintenance once per month is prolonged to the maintenance once in three months, the production days are increased, and the maintenance cost investment is reduced to bring direct economic benefits to factories.

Detailed Description

By adding the phosphorus-containing chemical substance of diphenoxy phosphorus, the phosphorus-containing chemical substance can be decomposed at high temperature to generate free radicals, the free radicals can be combined with the metal surface to form a film, the metal activity is reduced, and the wall of the reactor is passivated, so that the formation of coke is inhibited. In view of the fact that the acid value of domestic waste oil is about 2, the coke block softening effect is achieved by adding alkaline substance potassium hydroxide to neutralize the acid value and the combination effect of magnesium oxide and sodium dodecyl benzene sulfonate.

In addition, the asphaltene is the most complex component of chemical composition and structure in the residual oil, has the characteristics of strong polarity, large relative molecular mass, high aromaticity, high heteroatom content and the like, is the most difficult part to lighten in the residual oil processing process, and is the main reason for forming coke blocks, the asphaltene molecule is a condensed aromatic ring system core, a plurality of naphthenic rings are arranged around the condensed aromatic ring system core, and a plurality of alkyl side chains with different sizes are connected on the aromatic ring and the naphthenic rings to form the asphaltene molecule. During the hydrocracking reaction, the material can be sulfurized into active metal at the asphaltene position, and the hydrogenation saturation of the asphaltene can be better promoted, so that the condensation and polymerization of polycyclic aromatic hydrocarbon and the asphaltene are inhibited, and the formation of coked substances is prevented or reduced.

The mass ratio of the components is 50-80:10-30:5-15:10-20:2-5, and the preferable ratio is 60: 20: 10: 15: 3.

In view of the fact that the acid value of domestic waste oil is about 2, the usage amount of the coke inhibitor is 2-3 kg per ton of waste oil (clean oil), and the specific addition amount is determined by the acid value obtained by sampling and testing an oil tank in a laboratory of a factory.

The invention also provides a using method of the anti-coking agent, which comprises the steps of adding 3-4 times of water into the anti-coking agent, fully stirring the mixture into turbid liquid, pumping the turbid liquid into an oil tank, uniformly stirring the turbid liquid, feeding the waste oil in the tank into a distillation section, completely neutralizing the acid value, hardly gathering microscopic coke particles generated by a heating furnace on the surface of a furnace tube in the presence of magnesium oxide and sodium dodecyl benzene sulfonate, dispersing the microscopic coke particles on the whole waste oil system, pumping the waste oil system into a distillation tower along with a tower bottom raw material pump for lateral line separation, limiting the condensation of asphaltene by dodecyl sulfopropyl betaine, reducing the formation of coked substances, decomposing phosphorus diphenyl oxide at high temperature to generate free radicals, combining the free radicals with the metal surface to form a film, reducing the metal activity and passivating the wall of a reactor.

The invention also provides a method for delaying coking of a furnace tube, a filler and a heat exchanger in the waste oil distillation process, wherein the chemical coking inhibitor is injected into the raw materials before distillation in proportion, after the raw materials are uniformly stirred in a stirring tank, the raw materials are normally fed and are conveyed to a distillation tower through a pump, and the intermolecular interaction force of residual oil is reduced to achieve the purposes of neutralizing acidity and delaying coking by neutralizing the acid value and dispersing the freshly generated coke particles in the distillation process.

The following embodiments are described in detail to solve the technical problems by applying technical means to the present invention, and the implementation process of achieving the technical effects can be fully understood and implemented.

Chemical coke inhibitor

Potassium hydroxide, magnesium oxide, sodium dodecylbenzene sulfonate, phosphorous diphenoxy, and dodecylsulfopropyl betaine were mixed together to obtain a chemical scorch retarder for the following tests, the specific amounts being shown in table 1.

TABLE 1 amount of each scorch retarder (unit: g)

The test raw material is vacuum residue provided by Clarithrome petrochemical company, and the density is 0.96g/cm³(20 ℃ C.), viscosity 1180mm²The components of the aromatic gum are 37.43% of saturated components, 31.49% of aromatic components and 30.46% of gum at 100 ℃.

The experimental method comprises the following steps: by injecting the chemical coke inhibitor provided in example 1 into the vacuum residue before distillation, after the stirring in the stirring tank was uniform, the normal feed was sent to the distillation column by a pump, a condensed phase product oil sample was taken out on line at predetermined time intervals during the reaction, and then the coking rate in the taken oil sample was measured.

A detection instrument: and (3) extracting and separating coke in a Soxhlet extractor by using toluene as a solvent according to the volume ratio of the oil sample to the solvent of 1: 30. After the oil sample is extracted for 12h, the insoluble matters are coke. The component separation of heavy oil uses a flushing adsorption column method. About 15g of sample oil was weighed, n-heptane asphaltenes and n-butanol hard gums were separated using a soxhlet extractor, and saturated, aromatic and gums were separated in a neutral alumina column.

When the temperature is not too high, no obvious coking phenomenon exists in the coking induction period of oil residue thermal conversion, and obvious coking usually begins after a period of time, so the coking condition of the vacuum residue feeding at the high temperature of 500 ℃ is investigated.

The effect of adding various scorch retarders on the rate of coking and the composition of the oil samples were compared and the results are shown in Table 2.

TABLE 2 Effect of scorch retarder on coking Rate and oil sample composition

		Total amount of aromatic hydrocarbons + paraffin (%)	Coking Rate (%)
				1	Without addition of coke inhibitor	36.35％	45.29％
2	Addition of the scorch retarder of example 1	45.63％	27.18％
				3	Addition of scorch retarder of example 2	43.23％	38.62％
4	Addition of scorch retarder of example 3	49.18％	26.17％
				5	Comparative example 1 Coke inhibitor was added	44.93％	36.11％
6	Comparative example 2 Coke inhibitor	43.18％	33.16％
				7	Comparative example 3 Coke inhibitor	43.95％	37.17％

It can be seen from table 2 that the coking rate of the oil sample added with the anti-coking agent is significantly lower than that of the oil sample without the anti-coking agent, and the coking rate of the oil sample is significantly reduced after the anti-coking agent is added, and the addition of dodecyl sulfopropyl betaine can inhibit the condensation reaction and secondary reaction in the coking reaction and increase the liquid component by comparing the total white component of the aromatic hydrocarbon and paraffin (liquid component) in the whole oil sample.

All of the above mentioned intellectual property rights are not intended to be restrictive to other forms of implementing the new and/or new products. Those skilled in the art will take advantage of this important information, and the foregoing will be modified to achieve similar performance. However, all modifications or alterations are based on the new products of the invention and belong to the reserved rights.

The foregoing is directed to preferred embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow. However, any simple modification, equivalent change and modification of the above embodiments according to the technical essence of the present invention are within the protection scope of the technical solution of the present invention.

Claims

1. A chemical scorch retarder, characterized in that: potassium hydroxide, magnesium oxide, sodium dodecyl benzene sulfonate, phosphorus diphenoxylate and dodecyl sulfopropyl betaine;

the dosage mass ratio of the components is as follows: magnesium oxide: sodium dodecylbenzenesulfonate: di-phenoxy phosphorus: dodecyl sulfopropyl betaine =50-80:10-30:5-15:10-20: 2-5.

2. The process for producing a coke inhibitor according to claim 1, wherein: mixing the components together according to a certain proportion.

3. The method of using the scorch retarder according to claim 1, wherein: adding 3-4 times of water into the coking inhibitor, fully stirring the mixture into turbid liquid, pumping the turbid liquid into an oil tank, uniformly stirring the turbid liquid, and feeding waste oil in the tank into a distillation section.

4. A method for delaying coking of a furnace tube, a filler and a heat exchanger in a waste oil distillation process is characterized by comprising the following steps: the chemical coke inhibitor of claim 1 is proportionally injected into the raw materials before distillation, and after the raw materials are uniformly stirred in a stirring tank, the fed materials are conveyed to a distillation tower by a pump, and 2-3 kg of the coke inhibitor is used per ton of waste oil.