CN102816586B - Demetalization method for crude oil - Google Patents

Abstract

The invention relates to a demetalization method for crude oil. The method includes that (1) phosphate ester, oil soluble peroxide and the crude oil are mixed and react for a period of time>=30 min at the temperature of 80-180 DEG C, the mass of the crude oil serves as a standard, use amount of phosphate ester is 80-10000 mu g/g, use amount of oil soluble peroxide is 5-2000 mu g/g, and nickel content and/or vanadium content >=5 mu g/g; and (2) the crude oil obtained in the step (1) is processed through electro-desalting processing. The method has the advantages of being high in demetalization rate, small in chemical agent use amount, mild in reaction conditions, simple in process and devices and the like and is especially suitable for crude oil with high content of nickel and vanadium.

Description

A kind of method of crude oil demetallization

technical field

The invention belongs to a method for refining hydrocarbon oil. Specifically, the present invention relates to a method for demetalling crude oil. the

Background technique

With the deep exploitation of crude oil and the wide application of tertiary oil recovery technology, a large amount of heavy crude oil has been extracted, and the metal content of these crude oils, such as calcium, magnesium, sodium, iron, nickel, vanadium, copper, etc., is on the rise. Among the metal impurities in crude oil, nickel and vanadium are high in content and mostly exist in the form of porphyrin complexes and complex oil-soluble polymer compounds, and it is difficult to remove them in the process of electric desalting. Metal impurities in crude oil will have a negative impact on the secondary processing of crude oil, leading to catalyst poisoning, reduced activity, and increased reagent consumption, among which the hazards of nickel and vanadium are the most prominent. the

The metal compounds in crude oil decompose at high temperature, and the metals produced after the decomposition are deposited on the surface of the catalyst, thereby changing the properties of the catalyst. Metallic nickel is mainly deposited on the surface of the catalyst carrier, showing a strong dehydrogenation effect, increasing the yield of hydrogen and coke, that is, changing the selectivity of the catalyst without significantly affecting the catalyst activity. Metal vanadium is initially deposited on the surface of the catalyst, but it will gradually migrate to the molecular sieve. Due to the increase of sodium content, vanadium can form a low melting point eutectic with it, which destroys the structure of the molecular sieve, reduces the surface area of the catalyst, and reduces the activity. The poisoning effect is irreversible. In the process of heavy oil hydrotreating, because the demetallization reaction is the easiest to proceed, the removed metals are deposited on the surface of the catalyst in the form of sulfide, which blocks the pores of the catalyst and causes catalyst poisoning. the

At present, the industrial methods for removing metal impurities in crude oil are mainly hydrogenation method and solvent deasphalting method. Hydrodemetallization can effectively reduce nickel and vanadium in raw oil, but it is not suitable for raw materials with high metal content, and has the disadvantages of huge equipment investment and difficult regeneration of spent catalysts; solvent deasphalting is only suitable for removing asphalt content High crude oil, and can only remove nickel and vanadium in asphalt, and the investment is large and the operating cost is high. People have been exploring new methods of crude oil demetallization, such as chelation separation, solvent extraction, electrolytic reduction, thermal cracking, adsorption and so on. These new methods have not yet been industrialized due to the problems of low metal removal efficiency and high operating costs. the

Since the 1950s, foreign countries began to study the chemical removal of nickel and vanadium. Chemical removal of nickel and vanadium is to add chemical agents to the raw oil to make it react with nickel and vanadium compounds in the raw oil, and then separate the reaction products to achieve the purpose of nickel and vanadium removal. US4645589 discloses a method for demetallization of crude oil. The aqueous solution of phosphorus-containing compounds is reacted with raw oil in special equipment to extract metal nickel and vanadium into the water phase, and then separate the water phase to remove nickel and vanadium. In the method, the mass ratio of agent to crude oil is 0.01-0.04, the mass ratio of water to crude oil is 0.2-1, the reaction temperature is 80-200°C, the contact time is 5-60 minutes, and the removal rates of nickel and vanadium can reach 39% and 41% respectively. US4529503 discloses a method for demetalling hydrocarbon-containing streams, mixing elemental phosphorus or phosphorus-containing compounds (such as phosphorous acid) with metal-containing hydrocarbon oil, and reacting at 300-450°C under high pressure and hydrogen conditions to make elemental phosphorus or Phosphorus-containing compounds form oil-insoluble compounds with metals such as nickel and vanadium in hydrocarbon oil, and then the reaction products containing nickel and vanadium are separated by means of centrifugation, sedimentation or filtration. the

To sum up, the existing chemical demetallization technology has disadvantages such as large amount of chemical agents, complex process, high equipment requirements, harsh reaction conditions, etc., and its demetallization rate needs to be further improved. the

Contents of the invention

Aiming at the deficiencies of the prior art, the invention provides a method for demetalling crude oil. The method has the characteristics of high demetallization rate, small amount of chemical agents, mild reaction conditions, simple process and equipment, etc., and is especially suitable for crude oil with high nickel and vanadium content. the

A method for demetallizing crude oil, comprising:

(1) Mix phosphite, oil-soluble peroxide and crude oil, and react at 80-180°C for ≥30 minutes. Based on the quality of crude oil, the amount of phosphite is 80-10000 μg/g, and oil-soluble peroxide The dosage of the substance is 5-2000 μg/g, and the nickel content and/or vanadium content in the crude oil is ≥5 μg/g;

(2) Treating the crude oil obtained in step (1) by using an electric desalting process. the

The nickel content and/or vanadium content in the crude oil is preferably ≧20 μg/g. the

Based on the mass of crude oil, the amount of phosphite is preferably 400-5000 μg/g. the

Based on the mass of crude oil, the amount of oil-soluble peroxide used is preferably 25-1000 μg/g. the

Described phosphite can be selected from one of dimethyl phosphite, trimethyl phosphite, diethyl phosphite, triethyl phosphite, diphenyl phosphite and diisopropyl phosphite or Several, preferably dimethyl phosphite and/or trimethyl phosphite. the

The oil-soluble peroxide can be selected from isopropyl hydroperoxide, tert-butyl hydroperoxide, di-tert-butyl peroxide, 1,1,3,3-tetramethylbutyl hydroperoxide, peroxide Bis-(1-hydroxycyclohexane), 1,1-bis-(tert-butyl peroxy)cyclohexane, 2,2-bis-(tert-butyl peroxy)propane, 2,2-bis- One or more of (tert-butyl peroxide) butane, cumene peroxide, dicumyl peroxide, tert-butyl benzene peroxide and di-tert-butyl cumene hydroperoxide, preferably peroxide tert-butylbenzene. the

The reaction temperature in step (1) is preferably 100-140°C. the

The reaction time of step (1) is preferably 30-240 min. the

In step (1), one or more combinations of mechanical stirring, mixing valve and static mixer can be used to mix the phosphite, oil-soluble peroxide and crude oil. the

In step (2), a conventional electric desalting process can be used, and its operating conditions are generally: based on the quality of crude oil, the amount of demulsifier is 10-100 μg/g; based on the quality of crude oil as 100%, the amount of water injection 4%-10%; temperature 110-150°C; electric field strength 400-2000V/cm; residence time 20-120min. the

The present invention has no special limitation on the demulsifier, and conventional demulsifiers, such as polyether demulsifiers, can be selected. The polyether demulsifier can be polyoxyethylene-polyoxypropylene block copolymer, such as polyoxyethylene-polyoxypropylene block copolymer with fatty alcohol as initiator, amine as initiator Polyoxyethylene-polyoxypropylene block copolymer, polyoxyethylene-polyoxypropylene block copolymer with phenolic resin or phenolic resin as initiator or polyoxyethylene-polyoxypropylene with toluene diisocyanate as chain extender Oxypropylene block copolymer. The number average molecular weight of the polyoxyethylene-polyoxypropylene block copolymer can be 1,000 to 50,000. the

The reaction and electric desalination process in the present invention are preferably carried out in a continuous manner. the

The existing chemical demetallization technology has disadvantages such as large amount of chemical agents, complex process, high equipment requirements, harsh reaction conditions, etc., and its demetallization rate needs to be further improved. The present invention uses phosphite and oil-soluble peroxide to react with nickel and vanadium compounds in crude oil to convert nickel and vanadium compounds into precipitated, hydrophilic or water-soluble compounds, and then separates the reaction products through an electric desalting process, thereby To achieve the purpose of demetallization of crude oil. the

Compared with prior art, the present invention has the following advantages:

1. The nickel and vanadium removal rate of the present invention is high. By adopting the method of the invention, the removal rate of nickel can reach more than 60%, the removal rate of vanadium can reach more than 80%, and the total removal rate of calcium, magnesium and iron can reach more than 80%. the

2. The reaction temperature and pressure of the present invention are lower, and the amount of chemical agents is smaller. the

3. The equipment of the present invention is simple, the process is reasonable, and the operation is simple and convenient. The invention only needs to add a set of demetallization reaction equipment in front of the existing electric desalination device in the refinery, and the demetallization reaction process can adopt the same heat exchange process as the crude oil electric desalination process without adding any cold exchange equipment. Since the reaction temperature of the present invention is equivalent to the electric desalting temperature, the reacted crude oil can directly enter the electric desalting device of the refinery for desalting and dehydration, and remove nickel and vanadium at the same time. the

Detailed ways

Example 1

A domestic crude oil, metal content: nickel 33.5μg/g, vanadium 222.4μg/g, calcium 17.5μg/g, magnesium 1.6μg/g, iron 6.8μg/g. the

Add 1700 μg/g dimethyl phosphite and 300 μg/g tert-butylbenzene peroxide to the crude oil, stir and mix at 130° C., and react for 180 minutes. Then add the polyether demulsifier ST-14 (purchased from Shandong Binzhou Chemical Group) of 100 μ g/g in crude oil, the water of 6% of crude oil quality, after making demulsifier, water and crude oil fully mix, under 140 ℃, 1500V/ dehydration in an electric field of cm for 80 min to obtain a metal-free oil sample. The metal content of the oil sample was determined by inductively coupled plasma emission spectrometry, and the results are shown in Table 1. the

Table 1

project Nickel Vanadium calcium Magnesium iron Metal content after stripping/(μg/g) 11.5 42.2 3.0 0.3 1.6 Metal removal rate/% 65.7 81.0 82.9 81.3 76.5

Example 2

Test crude oil is identical with embodiment 1. The same method as in Example 1 was used to remove metals from crude oil, except that the amounts of dimethyl phosphite and tert-butylbenzene peroxide were both 15% of the amount in Example 1. The experimental results are shown in Table 2. the

Table 2

project Nickel Vanadium calcium Magnesium iron Metal content after stripping/(μg/g) 24.0 118.8 8.7 0.5 3.2 Metal removal rate/% 28.4 46.6 50.3 68.8 52.9

Example 3

Test crude oil is identical with embodiment 1. The same method as in Example 1 was used to remove metals from crude oil, except that the amount of dimethyl phosphite was 1940 μg/g, and the amount of tert-butylbenzene peroxide was 60 μg/g. The test results are shown in Table 3. the

table 3

project Nickel Vanadium calcium Magnesium iron Metal content after stripping/(μg/g) 17.2 78.3 2.9 0.4 1.8 Metal removal rate/% 48.7 64.8 83.4 75.0 73.5

Comparative example 1

Test crude oil is identical with embodiment 1. Adopt the method identical with embodiment 1 to remove metal in crude oil, difference is, the consumption of dimethyl phosphite is 2000 μ g/g, does not use t-butyl peroxide. The test results are shown in Table 4a. the

Table 4a

project Nickel Vanadium calcium Magnesium iron Metal content after stripping/(μg/g) 19.5 92.1 2.8 0.3 1.6 Metal removal rate/% 41.8 58.6 84.0 81.3 76.5

Example 4

Test crude oil is identical with embodiment 1. Add 2500 μg/g diethyl phosphite, 2000 μg/g diphenyl phosphite, and 500 μg/g isopropyl hydroperoxide to the crude oil, stir and mix at 120° C., and react for 180 minutes. Then add 100μg/g polyether demulsifier ST-14, crude oil mass 8% water, after fully mixing the demulsifier, water and crude oil, dehydrate 60min at 140°C in an electric field of 1800V/cm, and get metal-free oil sample. The metal content of the oil sample was determined by inductively coupled plasma emission spectrometry, and the results are shown in Table 4. the

Table 4

project Nickel Vanadium calcium Magnesium iron Metal content after stripping/(μg/g) 15.4 89.4 3.1 0.5 1.9 Metal removal rate/% 54.0 59.8 82.3 68.8 72.1

Example 5

An imported crude oil, metal content: nickel 13.4μg/g, vanadium 26.2μg/g, calcium 25.4μg/g, magnesium 2.8μg/g, iron 13.9μg/g. the

Add 800 μg/g triethyl phosphite and 200 μg/g 1,1-bis-(tert-butylperoxy)cyclohexane to the crude oil, stir and mix at 130° C., and react for 60 minutes. Then add 20μg/g polyether demulsifier ST-14 and 5% water of crude oil quality, after fully mixing the demulsifier, water and crude oil, dehydrate in an electric field of 600V/cm at 110°C for 40min, and obtain metal-removed oil sample. The metal content of the oil sample was determined by inductively coupled plasma emission spectrometry, and the results are shown in Table 5. the

table 5

project Nickel Vanadium calcium Magnesium iron Metal content after stripping/(μg/g) 6.9 10.2 7.8 1.0 5.6 Metal removal rate/% 48.5 61.1 69.3 64.3 59.7

Example 6

Test crude oil is identical with embodiment 5. Add 4000 μg/g of trimethyl phosphite, 750 μg/g of diisopropyl phosphite, 300 μg/g of di-tert-butyl peroxide, and 150 μg/g of dicumyl peroxide to the crude oil, at 140 °C Mix under stirring, react for 150min. Then add 60μg/g polyether demulsifier ST-14, crude oil mass 10% water, after fully mixing the demulsifier, water and crude oil, dehydrate 100min at 140°C in an electric field of 1400V/cm, and get metal-free oil sample. The metal content of the oil sample was determined by inductively coupled plasma emission spectrometry, and the results are shown in Table 6. the

Table 6

project Nickel Vanadium calcium Magnesium iron Metal content after stripping/(μg/g) 4.5 5.0 4.9 0.9 3.4 Metal removal rate/% 66.4 80.9 80.7 67.9 75.5

Claims (11)

1. A method for crude oil demetallization, comprising: (1) Mix phosphite, oil-soluble peroxide and crude oil, and react at 80-180°C for ≥30 minutes. Based on the quality of crude oil, the amount of phosphite is 80-10000 μg/g. Oil-soluble peroxide The dosage of the substance is 5-2000 μg/g, and the nickel content and/or vanadium content in the crude oil is ≥5 μg/g; (2) adopt electric desalting process to process the crude oil obtained in step (1); the technological conditions of electric desalting are: take the quality of crude oil as a benchmark, the consumption of demulsifier is 10～100 μ g/g; Take the quality of crude oil as 100%, The amount of water used is 4%-10%; the temperature is 110-150°C; the electric field strength is 400-2000V/cm; and the residence time is 20-120min. 2. The method according to claim 1, characterized in that the nickel content and/or vanadium content in the crude oil is ≥20 μg/g. 3. The method according to claim 1, characterized in that, based on the quality of crude oil, the amount of phosphite is 400-5000 μg/g. 4. The method according to claim 1, characterized in that, based on the quality of crude oil, the amount of oil-soluble peroxide is 25-1000 μg/g. 5. according to the described method of claim 1, it is characterized in that, described phosphite is selected from dimethyl phosphite, trimethyl phosphite, diethyl phosphite, triethyl phosphite, diphosphite One or more of phenyl ester and diisopropyl phosphite. 6. according to the described method of claim 1, it is characterized in that, described oil-soluble peroxide is selected from isopropyl hydroperoxide, tert-butyl hydroperoxide, di-tert-butyl peroxide, 1,1, 3,3-tetramethylbutyl hydroperoxide, bis-(1-hydroxycyclohexane) peroxide, 1,1-bis-(tert-butyl peroxy)cyclohexane, 2,2-bis-( tert-butyl peroxide) propane, 2,2-bis-(tert-butyl peroxide) butane, cumene peroxide, dicumyl peroxide, tert-butyl peroxide and di-tert-butyl isohydroperoxide One or more of propylene benzene. 7. The method according to claim 1, characterized in that the reaction temperature in step (1) is 100-140°C. 8. The method according to claim 1, characterized in that the reaction time of step (1) is 30-240 min. 9. according to the described method of claim 1, it is characterized in that, in step (1), adopt the combination of one or more in mechanical stirring, mixing valve, static mixer to make phosphite, oil-soluble peroxide Mix with crude oil. 10. according to the described method of claim 1, it is characterized in that, described demulsifier is the polyoxyethylene-polyoxypropylene block copolymer of aliphatic alcohol as initiator, the polyoxyethylene with amine as initiator - Polyoxypropylene block copolymer, polyoxyethylene-polyoxypropylene block copolymer with phenolic resin or phenolic resin as initiator or polyoxyethylene-polyoxypropylene block copolymer with toluene diisocyanate as chain extender segment copolymers. 11. The method according to claim 10, characterized in that the number average molecular weight of the polyoxyethylene-polyoxypropylene block copolymer is 1,000-50,000.