Organic amine neutralizer for atmospheric-vacuum distillation unit and application thereof

Abstract

The present application relates to a kind of organic amine neutralizer for atmospheric and vacuum unit and its application, belong to neutralizer technical field.The neutralizer of the present application is compounded by multiple organic amines, and the main component is ethylene amine and ethanol amine.Directly according to formula, single-component organic amine is added to compound, it can also be prepared by two-step combination of first synthesis and then compounding, the latter can reduce cost, with higher economic benefit.The organic amine neutralizer of the present application is applied to refinery atmospheric and vacuum unit fractionating column top volatile line corrosion prevention, can replace conventional ammonia water.It has the following advantages: suitable for tower top volatile line environment in distillation range;easily soluble in water at dew point temperature, not corrosive in dew point area;with low melting point, good water solubility, no ammonium salt scale, not accumulated, not blocked;stable pH, easy to control;safe and environmentally friendly;good corrosion inhibition effect;excellent performance, high cost performance, etc.

Description

TECHNICAL FIELD

[0001] The present application relates to an organic amine neutralizer for a crude oil distillation unit and application thereof, and belongs to the technical field of neutralizers. BACKGROUND

[0002] In the process of crude oil distillation, HCl and H2S are inevitably produced in the crude oil distillation unit of a refinery. HCl and H2S do not cause corrosion when there is no water. However, as the temperature of the overhead effluent gradually decreases to the dew point temperature, water condenses on the surface of the equipment in the form of a film. At this time, the concentration of hydrogen chloride is the highest and the pH value is the lowest. The HCL-H2S-H2O corrosion environment at the low-temperature part of the overhead is very severe, and the corrosion protection of the equipment at this part is particularly important. Domestic and foreign refineries generally use the "three injections after one removal" process protection measures (crude oil desalting, ammonia water injection, water injection, and corrosion inhibitor injection). Among them, ammonia water is injected to neutralize the acidic substances in the condensate. However, NH3 has a very low boiling point (-33℃), and after being injected into the overhead, NH3 is basically in the gas phase, and the concentration in the liquid phase is not more than 10% (about 2% when the overhead temperature is 120℃). Therefore, the initial condensation zone of water is very poor in neutralization by NH3.

[0003] In the initial condensation zone of the overhead, when the condensate water reaches 5%, about 50% of HCl has dissolved into the condensate water; when the condensate water reaches 50%, almost all of the HCl has dissolved into the condensate water.

[0004] Therefore, it is difficult to control HCl in the initial condensation zone of water and in the liquid phase by NH3. If the injection rate of NH3 as a neutralizer fluctuates by 5%, the pH value will have a large fluctuation. If the pH value changes to the low side, acidic corrosion will occur. If the pH value changes to the high side, high-boiling salts will be deposited, resulting in under-deposit corrosion. Therefore, corrosion still occurs at the "dew point part". Even if the pH value of the condensate at the discharge port is 9, the pH value at the dew point area is still 2-3. Therefore, this part is prone to destructive corrosion. SUMMARY

[0005] The technical problem solved by the present application is to provide an organic amine neutralizing agent for a crude oil distillation unit, which is compounded by multiple organic amines and classified into ethylene amine and ethanol amine.

[0006] To solve the above technical problem, the technical solution of the present application is an organic amine neutralizing agent for a crude oil distillation unit, which is compounded by multiple organic amines or synthesized and then compounded, and includes ethylenediamine EDA, diethylenetriamine DETA, triethylenetetramine TETA, piperazine, monoethanolamine MEA, diethanolamine DEA, N-methylethanolamine MMEA, N-methyldiethanolamine MDEA, water-soluble imidazoline and water.

[0007] The mass fraction of each component is: ethylenediamine EDA 45-87 parts; diethylenetriamine DETA 6-16 parts; triethylenetetramine TETA 2-6 parts; piperazine 4-10 parts; monoethanolamine MEA 14-26 parts; diethanolamine DEA 2-6 parts; N-methylethanolamine MMEA 4-10 parts; N-methyldiethanolamine MDEA 4-10 parts; imidazoline 1 part; and water 45-87 parts.

[0008] Preferably, the mass fraction of each component is: ethylenediamine EDA 22.5-43.5%; diethylenetriamine DETA 3-8%; triethylenetetramine TETA 1-3%; piperazine 2-5%; monoethanolamine MEA 7-13%; diethanolamine DEA 1-3%; N-methylethanolamine MMEA 2-5%; N-methyldiethanolamine MDEA 2-5%; imidazoline 0.5%; and water 22.5-43.5%.

[0009] Preferably, the neutralizing agent is directly compounded by one-step method using single organic amine, imidazoline and water as raw materials, or two types of mixed organic amines, i.e., ethylene amine and ethanol amine, are prepared by synthesis, and then the ethylene amine, ethanol amine, imidazoline and water are compounded.

[0010] The main raw materials for the synthesis of the neutralizing agent are preferably 1,2-dichloroethane (DCE), ethylene oxide (EO), ammonia, aqueous methylamine and a catalyst.

[0011] The synthesis of the neutralizing agent is preferably prepared by the dichloroethane method for ethylenediamine, the ethylene oxide method for ethanolamine and the ethylene oxide method for methyl ethanolamine, and appropriate side reactions are added. In the later stage of the reaction, the products and by-products of the same category are not deeply separated, and the mixed products containing various organic amines of the same category are directly used as the main raw materials for the preparation of the neutralizing agent.

[0012] The mixture contains 25-55 wt% of mixed ethyleneamine, 11-30 wt% of mixed ethanolamine, 0.5 wt% of water-soluble imidazoline and 20-50 wt% of water.

[0013] The synthesis method of the neutralizing agent is preferably as follows:

[0014] (1) Preparation of mixed ethyleneamine: DCE, ammonia, catalyst and dichloromethane are subjected to ammonolysis reaction under certain conditions to replace the chlorine in DCE; process conditions: pressure 3-4 MPa, reaction time 25-40 min, reaction temperature 120-140°C; ammonia content 30-35 wt%, DCE content 99.9 wt%; ammonia to DCE molar ratio 20:1; catalyst is a mixture of 2,2-dipyridyl, cuprous chloride and ferrous chloride in a mass ratio of 1:1:1, and the catalyst addition amount is 0.5 wt% of the mass of dichloromethane; the reaction product is separated by vacuum distillation to obtain the target component, and the conditions are 0.5 MPa, 90-175°C.

[0015] (2) Preparation of mixed ethanolamine: EO is reacted with ammonia and aqueous methylamine; process conditions: the reaction is divided into two stages, in the first stage, EO is reacted with ammonia, the reaction is controlled at a temperature of 40-50°C, the reaction time is 30 min, and the pressure is 0.1-0.3 MPa; in the second stage, aqueous methylamine solution is added, and EO is continuously introduced for reaction, and then the temperature is increased to 130°C, and the reaction is carried out at a constant temperature for 35 min under the catalysis of water and a pressure of 2.5 MPa; ammonia concentration is 20-25 wt%; aqueous methylamine concentration is 40 wt%; ethylene oxide content is 99.9 wt%; ammonia to EO molar ratio is 2:1; methylamine to EO molar ratio is 3:1; the reaction product is separated by vacuum distillation to obtain the target component, and the conditions are 0.5 MPa, 115-210°C.

[0016] (3) mixed organic amine complex: the mixed ethylene amine, mixed ethanol amine prepared by the above steps are mixed with water to obtain a mixed solution of multi-component organic amine, and finally a trace amount of water-soluble imidazoline is added to obtain a mixed organic amine neutralizer with certain corrosion inhibition effect; the complexing amount is: mixed ethylene amine 25-55wt%, mixed ethanol amine 11-30wt%, water-soluble imidazoline 0.5wt%, and water 20-50wt%.

[0017] Preferably, the blending preparation method of the neutralizer is as follows: a certain amount of water (desalted water or distilled water) is added to a blending kettle, stirring is started (stirring speed 75r / min), and the kettle jacket cooling water is started, and the kettle temperature is controlled to be less than 40℃; then various organic amines are added, and the organic amines are added within 40-60min, and then stirring is continued for 30min; finally, water-soluble imidazoline is added, and stirring is continued for 10min. The mixed organic amine neutralizer is prepared.

[0018] The addition ratio of various organic amines is: EDA 22.5-43.5%; DETA 3-8%; TETA 1-3%; 2-5%; MEA 7-13%; DEA 1-3%; MMEA 2-5%; MDEA 2-5%; imidazoline 0.5%; and water 22.5-43.5%.

[0019] Preferably, the synthesis method of the neutralizer is combined with the following steps:

[0020] (1) preparation of mixed ethylene amine: 1,2-dichloroethane DCE and ammonia water are subjected to ammonolysis reaction under certain conditions to replace the chlorine in DCE, and the reaction is carried out according to the preferred raw material molar number and process conditions. The product is separated by rotary evaporator under reduced pressure to obtain the required components as the intermediate of the blending neutralizer-mixed ethylene amine. The conversion rate of 1,2-dichloroethane (molar titration) is greater than 99%; the content of each component in the obtained mixed ethylene amine (determined by chromatography) is: EDA>58wt%, DETA+TETA<20wt%, and piperazine>5wt%.

[0021] The reaction equation is as follows: ClCH2CH2Cl+NH3→ClCH=CH2+NH4Cl; ClCH2CH2Cl+2NH3→NH2CH2CH2NH2•2HCl;

[0022] ClCH2CH2Cl+NH2CH2CH2NH2•2HCl+2NH3→NH4Cl+NH2CH2CH2NHCH2CH2NH2•3HCl;

[0023] ClCH2CH2Cl + NH2CH2CH2NHCH2CH2NH2 • 3HCl + 2NH3→ NH4Cl + NH2CH2CH2NHCH2CH2NHCH2CH2NH2 • 4HCl;

[0024] ClCH2CH2Cl + NH2CH2CH2NH2→ C4H 10 N2 • 2HCl.

[0025] Main experimental apparatus: high-pressure reactor, adjustable speed, with jacket or coil; rotary evaporator, vacuum pump.

[0026] Preferred process conditions: pressure 3-4 MPa, reaction time 25-40 min, reaction temperature 120-140°C; the reaction product is separated by vacuum distillation to separate the target component, the condition is 0.5 MPa, 90-175°C.

[0027] Preferred raw material ratio: ammonia concentration 30-35wt%, DCE content 99.9%; ammonia and DCE molar ratio 20:1.

[0028] Preferred catalyst: 2,2-dipyridyl, cuprous chloride, ferrous chloride, mass ratio 1:1:1, addition amount 0.5wt% of dichloromethane.

[0029] (2) Preparation of mixed ethanolamine: EO is reacted with ammonia water and methylamine aqueous solution, and a multi-component mixed ethanolamine is generated by optimizing the raw material ratio and process conditions. The product is collected by rotary evaporator vacuum distillation to collect ethanolamine components, and the final product can be used as an intermediate-mixed ethanolamine of blending neutralizer. The conversion rate of EO (Furher titration) is >98%; the content of each component in the obtained mixed ethanolamine (determined by chromatography) is: MEA >53wt%, DEA <8.0wt%, MMEA >18wt%, MDEA <20wt%. The reaction equation is as follows: NH3+C2H4O→H2NCH2CH2OH; H2NCH2CH2OH+C2H4O→HN(CH2CH2OH)2; HN(CH2CH2OH)2+C2H4O→N(CH2CH2OH)3;

[0030] CH3NH2+C2H4O→CH3NHCH2CH2OH; CH3NH2+2C2H4O→CH3N(CH2CH2OH )2 。

[0031] Main experimental apparatus: high-pressure reactor, adjustable speed, with jacket or coil; vacuum pump, rotary evaporator.

[0032] The preferred process conditions are that the reaction is divided into two stages, the first stage is that EO reacts with ammonia, the reaction is controlled at a temperature of 40-50 DEG C, the reaction time is 30 min, and the pressure is 0.1-0.3 MPa; after the reaction is completed, the aqueous methylamine solution is added, the EO is continuously introduced to participate in the reaction, the temperature is increased to 130 DEG C, the reaction is carried out at a constant temperature for 35 min under the catalysis of water, and the pressure is 2.5 MPa; the reaction product is separated by reduced pressure distillation to separate the target component, and the condition is that the pressure is 0.5 MPa and the temperature is 115-210 DEG C.

[0033] The preferred raw material ratio is that the ammonia water concentration is 20-25 wt%, the aqueous methylamine solution concentration is 40 wt%, the content of the ethylene oxide is 99.9%, the molar ratio of ammonia to EO is 2:1, and the molar ratio of methylamine to EO is 3:1.

[0034] (3) mixed organic amine compounding: the mixed ethylene amine, the mixed ethanol amine and water prepared in the above steps are compounded to obtain a mixed solution of multi-component organic amine, and finally a trace amount of water-soluble imidazoline is added, and stirring is carried out for 30 min (stirring speed is 60 r / min). Finally, a mixed organic amine neutralizing agent with certain corrosion inhibition effect is prepared.

[0035] The preferred compounding amount is that the mixed ethylene amine is 25-55 wt%, the mixed ethanol amine is 11-30 wt%, the water-soluble imidazoline is 0.5 wt%, and the water is 20-50 wt%.

[0036] In order to solve the above technical problems, the neutralizing agent compounded according to the technical scheme of the present application is applied to the overhead volatile line of a crude oil distillation unit, and the preferred application method is that the neutralizing agent is pumped from a raw material barrel to a neutralizing agent batching tank; the neutralizing agent is injected into the overhead system of the fractionating tower by using an injection pump, the use amount is adjusted according to the content of the acidic corrosive substances in the system to a relatively appropriate proportion, so that the operating conditions of the overhead are stable; when used, the neutralizing agent is diluted with water to 5-10%, or the neutralizing agent can be directly injected.

[0037] The present application has the following beneficial effects: the neutralizing agent prepared by the present application is mainly composed of various organic amines and imidazolines, has excellent neutralizing effect, and has certain corrosion inhibition effect. The neutralizing agent is a light-colored liquid, is soluble in water, has a density of 0.95-1.05 g / cm 3 , a pH value of >11, and a corrosion inhibition rate of >70%. The neutralizing agent overcomes the shortcomings of traditional ammonia injection in a crude oil distillation unit, and can effectively reduce the corrosion of the condensing system in the low-temperature light oil part of the overhead.

[0038] The neutralizer body of the present application is distilled at 110-150 DEG C, and the slope of the main part curve is small. The distillation temperature range conforms to the three top volatile line environment of the atmospheric-vacuum unit, especially the atmospheric tower top which is more seriously corroded. When the organic amine neutralizer is injected, the pH value will become stable with the change of temperature, and it is in the gas phase at the upstream of the condensation zone and is easily dissolved in water in the condensation zone, fully reacts with HCl, and the pH value will not obviously increase or decrease, which can play the role of full coverage of neutralization and corrosion prevention of the tower top volatile line equipment.

[0039] In the distillation tower top oil gas, there are a large number of acidic substances. Due to gradual condensation, the temperature drops to the dew point area of HCl and H2S, which causes serious dew point corrosion of the equipment. Because the solubility of ammonia water and HCl in water is different, the solubility of ammonia water in the dew point temperature range decreases sharply, while the solubility of HCl is not affected by temperature and changes little. Therefore, ammonia water cannot be quickly dissolved in the condensate to neutralize HCl and H2S acidic substances.

[0040] However, the organic amine neutralizer prepared by this method is not affected by temperature and is easily dissolved in water, which can quickly dissolve in the condensate to neutralize HCl and H2S acidic substances, and the pH value of the condensate at the tower top discharge outlet is consistent with the change in the dew point area. In the process of industrial application, the dew point corrosion of the device injecting ammonia water has been a long-standing problem, and the dew point corrosion of the device injecting mixed organic amine neutralizer will be significantly reduced. The combination of injecting mixed organic amine neutralizer and low-temperature corrosion inhibitor can make the corrosion rate below 0.2 mm / a.

[0041] When ammonia is injected into the tower top volatile line of the atmospheric-vacuum unit of the refinery, high melting point (> 340 DEG C) ammonium chloride scale is generated near the dew point area, which can generate acidic ammonium bisulfide when contacting with hydrogen sulfide in the oil gas, causing secondary corrosion under the scale. The salt after the reaction of the mixed amine type neutralizer has a lower melting point and is quickly dissolved in water with high solubility, which does not exist under the scale corrosion and will not block the pipeline.

[0042] The pH value of the "three top water" condensate in the atmospheric-vacuum unit can be basically stabilized at 6-8 by injecting the neutralizer prepared by this method, while the pH value of the condensate fluctuates greatly by injecting ammonia water, about 3-9, and is easy to corrode and difficult to control. In the pH 6-8 range, ammonia water and a certain organic amine cannot effectively control, while mixed organic amine can effectively control.

[0043] The neutralizer prepared by the present application can be mutually soluble with water in any proportion, and the initial boiling point is greater than 100 DEG C. Compared with ammonia water, it is not easy to volatilize at room temperature, has no pungent odor, and the use environment is safer and more environmentally friendly.

[0044] The neutralizer prepared by the present application contains water-soluble imidazoline, which can form a firm and stable protective film on the metal surface, slow down the corrosion of the pipeline and equipment, and effectively prolong the service life of the equipment and the operation period.

[0045] After adding the neutralizing agent of this invention to the atmospheric and vacuum distillation unit, the following conditions can be met: the properties of the raw materials are basically stable, the unit operates normally, and the process operation is stable.

[0046] (1) The pH value of the distillate from the top of the tower should be controlled at 6-8.

[0047] (2) The neutralizing agent will not have an adverse effect on the stability of the equipment or the quality of the product.

[0048] (3) The neutralizing agent has no adverse effects on subsequent equipment and sewage treatment equipment.

[0049] (4) Neutralizing agent dosage: The recommended dosage is 5 to 20 ppm (relative to the tower feed rate).

[0050] By synthesizing mixed enamines and alcoholamines and then compounding them into an organic amine neutralizer, the cost is reduced by about 40% compared to direct compounding. If the raw materials are recycled and reused, the cost can be further reduced. Moreover, the organic amine neutralizer synthesized and compounded has a higher alkalinity, which is beneficial to effectively reduce the corrosion of the condensation system in the low-temperature light oil section at the top of the tower. Attached Figure Description

[0051] The present invention will be further described below with reference to the accompanying drawings.

[0052] Figure 1 It is a neutralization curve of hydrochloric acid titration.

[0053] Figure 2 This is a flowchart of the industrial application of the neutralizing agent of the present invention. Detailed Implementation

[0054] The present invention will be further described below with reference to embodiments.

[0055] Example 1

[0056] A one-step method was used to prepare a mixed organic amine neutralizing agent. The preparation process is as follows: 200g of distilled water was added to a 1000ml small-scale mixing vessel, and stirring was started (75rpm). Various organic amines were slowly added sequentially: EDA 175.2g; DETA 23.4g; TETA 12.6g; piperazine hexahydrate 31.1g; MEA 53.4g; DEA 11.4g; MMEA 15g; MDEA 13.8g. Cooling water was circulated through the jacket to control the vessel temperature below 40℃. After the mixed amines were added, the mixture was stirred for 30 minutes. A clean 100ml beaker was taken, and 61.0g of distilled water was added first, followed by 3.0g of water-soluble imidazoline. The mixture was stirred evenly with a glass rod to obtain an imidazoline aqueous solution. Finally, the imidazoline aqueous solution was poured into the small-scale mixing vessel, stirred for 10 minutes, and then discharged into sample bottles. The preparation of the mixed organic amine neutralizing agent was complete.

[0057] Table 1 Content of each component in the final product

[0058]

[0059] Table 2 Physical and chemical data of the product

[0060]

[0061] Table 3 Distillation range of the product

[0062]

[0063] The cost of raw materials used in this example preparation: 12401.9 yuan / ton.

[0064] Example 2

[0065] The mixed organic amine neutralizer was prepared by one-step blending. The preparation process was as follows: 200 g of distilled water was added to a 1000 ml small test blending kettle, and stirring was started (speed 75 rpm), and various organic amines were slowly added in turn: EDA 210.6 g; DETA 19.8 g; TETA 10.8; piperazine hexahydrate 31.1 g; MEA 46.2 g; DEA 9.6 g; MMEA 14.4 g; MDEA 15.6 g; cooling water was passed through the jacket, and the kettle temperature was controlled to be less than 40°C. After the addition of the mixed amine was completed, stirring was carried out for 30 min; a clean 100 ml beaker was taken, 38.8 g of distilled water was first added, then 3.0 g of water-soluble imidazoline was added, and it was stirred uniformly with a glass rod to prepare an imidazoline aqueous solution; finally, the imidazoline aqueous solution was poured into the small test blending kettle, and stirring was carried out for 10 min, the discharge was packed into a sample bottle, and the preparation of the mixed organic amine neutralizer was completed.

[0066] Table 4 Content of each component in the final product

[0067]

[0068] Table 5 Physical and chemical data of the product

[0069]

[0070] Table 6 Distillation range of the product

[0071]

[0072] The cost of raw materials used in this example preparation: 13331.9 yuan / ton.

[0073] Example 3

[0074] The mixed organic amine neutralizer is prepared by synthesis and blending. The preparation process is as follows: 1. Preparation of mixed ethylene amine: 33.0wt% ammonia water 3100.3 g and catalyst (2,2-dipyridine, cuprous chloride, ferrous chloride, mass ratio is 1:1:1) 1.5 g are added into a 5000 ml high-pressure reactor; a stirrer is kept rotating at a speed of 175 rpm, then raw material dichloroethane 297.0 g is introduced into the reactor, and the reactor jacket is heated; the reaction pressure is 3.5 MPa, the reaction temperature is 130°C, and the reaction time is 30 min. After the reaction is completed, the reaction mixture is transferred to a distillation device and separated by rotary evaporator pressure distillation (-0.5 MPa, 90-175°C) to obtain a mixture of ethylenediamine, piperazine, diethylenetriamine and a small amount of triethylenetetramine 242.2 g; the separated ammonia water and heavy component residue can be used for comprehensive utilization.

[0075] The reaction equation is as follows: ClCH2CH2Cl+NH3→ClCH=CH2+NH4Cl; ClCH2CH2Cl+2NH3→NH2CH2CH2NH2•2HCl;

[0076] ClCH2CH2Cl+NH2CH2CH2NH2•2HCl+2NH3→NH4Cl+NH2CH2CH2NHCH2CH2NH2•3HCl;

[0077] ClCH2CH2Cl+NH2CH2CH2NHCH2CH2NH2•3HCl+2NH3→NH4Cl+NH2CH2CH2NHCH2CH2NHCH2CH2NH2•4HCl;

[0078] ClCH2CH2Cl+NH2CH2CH2NH2→C4H 10 N2•2HCl.

[0079] Product analysis: sampling is performed after the reaction is completed, and the conversion rate of dichloroethane is 99.1% measured by Mohr titration; the composition of various ethylene amines after distillation is determined by chromatography, and the content is as follows: ethylenediamine 58.5wt%, diethylenetriamine 13.1wt%, triethylenetetramine 3.9wt%, and piperazine 6.9wt%.

[0080] Table 7 Physicochemical data

[0081]

[0082] 2. Preparation of mixed ethanolamine: In a 2000 ml autoclave, 332.1 g of 24.0 wt% ammonia water was added and the stirrer was kept rotating at 175 rpm, then the raw material EO 103.1 g was slowly introduced into the reactor, the reaction temperature was 43°C (pay attention to temperature control due to reaction heat), the reaction pressure was 0.1-0.3 MPa, and the reaction time was 60 min.

[0083] After the above reaction was completed, 540.9 g of 40 wt% methylamine aqueous solution was added to the reactor; the stirrer was kept rotating at 175 rpm, then the temperature was raised to 130°C, and then the raw material EO 106.9 g was slowly introduced into the reactor, the reaction pressure was 2.5 MPa, and the reaction time was 30 min. After the reaction was completed, the mixture of MEA, MMEA, and MDEA 386.0 g was separated by rotary evaporation under reduced pressure (-0.5 MPa, 115-210°C).

[0084] The reaction equation is as follows: NH3+C2H4O→H2NCH2CH2OH; H2NCH2CH2OH+C2H4O→HN(CH2CH2OH)2;

[0085] HN(CH2CH2OH)2+C2H4O→N(CH2CH2OH)3; CH3NH2+C2H4O→CH3NHCH2CH2OH; CH3NH2+2C2H4O→CH3N(CH2CH2OH)2.

[0086] Product analysis: After the reaction was completed, sampling was performed, and the conversion rate of EO was 98.9% as determined by the Volhard method; the composition of each type of ethanolamine after distillation was determined by chromatography, and the content was as follows: MEA 53.1 wt%, DEA 6.0 wt%, MMEA 18.8 wt%, and MDEA 15.7 wt%.

[0087] Table 8

[0088]

[0089] 3. Mixed organic amine compounding: In a 500 ml beaker, 200.0 g of the mixed vinylamine prepared in the above step, 80.0 g of the mixed ethanolamine, and a certain amount of water were mixed, stirred uniformly, and a multi-component organic amine mixed solution 398 g was obtained, then 2 g of water-soluble imidazoline was added, and stirred uniformly to prepare a mixed organic amine neutralizing agent product.

[0090] Table 9 Content of each component in the final product

[0091]

[0092] Table 10 Physical and chemical data of the product

[0093]

[0094] Table 11 Product distillation range determination

[0095]

[0096] The cost of raw materials used in this example preparation: 9257 yuan / ton.

[0097] Example 4

[0098] The mixed organic amine neutralizer was prepared by synthesis and blending, and the preparation process was as follows:

[0099] 1. Preparation of mixed ethylene amine: In a 5000 ml high pressure reactor, 31.0 wt% ammonia water 3422.2 g and catalyst (2, 2-dipyridyl, cuprous chloride, ferrous chloride, mass ratio of 1:1:1) 1.5 g were added; keep the stirrer rotating at 175 rpm, then add the raw material dichloroethane 308.1 g into the reactor, and start the reactor jacket heating, the reaction pressure is 3.5 MPa, the reaction temperature is 130℃, the reaction time is 30 min. After the reaction, cool to room temperature, transfer the reaction mixture to a distillation apparatus, and separate by rotary evaporator pressure distillation (-0.5 MPa, 90~175℃) to obtain a mixture of ethylenediamine, piperazine, diethylenetriamine and a small amount of triethylenetetramine 260.9 g, the separated ammonia water and heavy component residue can be used for comprehensive utilization.

[0100] The reaction equation is as follows:

[0101] ClCH2CH2Cl + NH3→ ClCH=CH2 + NH4Cl

[0102] ClCH2CH2Cl + 2NH3→ NH2CH2CH2NH2•2HCl

[0103] ClCH2CH2Cl + NH2CH2CH2NH2•2HCl + 2NH3→ NH4Cl + NH2CH2CH2NHCH2CH2NH2•3HCl

[0104] ClCH2CH2Cl + NH2CH2CH2NHCH2CH2NH2•3HCl + 2NH3→ NH4Cl + NH2CH2CH2NHCH2CH2NHCH2CH2NH2•4HCl

[0105] ClCH2CH2Cl + NH2CH2CH2NH2→ C4H 10 N2•2HCl.

[0106] Product analysis: The conversion rate of dichloroethane was 99.0% measured by titration with Mohr method. The composition of ethyleneamines after distillation was determined by chromatography, and the content was: ethylenediamine 59.9 wt%, diethylenetriamine 13.0 wt%, triethylenetetramine 3.7 wt%, and piperazine 6.8 wt%.

[0107] Table 12 Physicochemical data

[0108]

[0109] 2. Preparation of mixed ethanolamines: 435.1 g of 22.0 wt% ammonia water was added into a 2000 ml high-pressure reactor with a stirrer rotating at a speed of 175 rpm, and then 124.7 g of raw material EO was introduced into the reactor. The reaction temperature was 44°C (the reaction was exothermic, and the temperature was controlled), the reaction pressure was 0.1-0.3 MPa, and the reaction time was 60 min.

[0110] After the above reaction was completed, 650.1 g of 40 wt% methylamine aqueous solution was further added into the reactor, and the stirrer was kept rotating at a speed of 175 rpm. Then the temperature was increased to 130°C, and 131.0 g of raw material EO was slowly introduced into the reactor. The reaction pressure was 2.5 MPa, and the reaction time was 30 min. After the reaction was completed, a mixture of MEA, MMEA and MDEA was separated by vacuum distillation (-0.5 MPa, 115-210°C) using a rotary evaporator, and 470.8 g of the mixture was obtained.

[0111] The reaction equation is as follows:

[0112] NH3+C2H4O→H2NCH2CH2OH

[0113] H2NCH2CH2OH+C2H4O→HN(CH2CH2OH)2

[0114] HN(CH2CH2OH)2+C2H4O→N(CH2CH2OH)3

[0115] CH3NH2+C2H4O→CH3NHCH2CH2OH

[0116] CH3NH2+2C2H4O→CH3N(CH2CH2OH)2

[0117] Product analysis: The conversion rate of EO was 98.2% measured by Fehling method. The composition of ethanolamines after distillation was determined by chromatography, and the content was: MEA 54.9 wt%, DEA 5.9 wt%, MMEA 18.9 wt%, and MDEA 14.9 wt%.

[0118] Table 13 Physicochemical data

[0119]

[0120] 3. Mixed organic amine compounding: In a 500ml beaker, add the mixed ethylene amine 200.0g, mixed ethanol amine 100.0g prepared in the above step and mix with a certain amount of water, stir evenly to obtain a multi-component organic amine mixed solution 497.5g, then add water-soluble imidazoline 2.5g, and stir evenly to prepare a mixed organic amine neutralizer product.

[0121] Table 14 Content of each component in the final product

[0122]

[0123] Table 15 Physical and chemical data of the product

[0124]

[0125] Table 16 Product distillation range determination

[0126]

[0127] The cost of raw materials used in this example preparation: 6900 yuan / ton.

[0128] Table 17 The neutralizer prepared by this example can achieve the following quality indicators

[0129]

[0130] Example 5

[0131] The comparison results of the neutralizers of Examples 1-4 with commercially available organic amine neutralizers and ammonia water are as follows:

[0132] Table 18 Comparison of neutralizers of Examples 1-4 with commercially available organic amine neutralizers and ammonia water

[0133]

[0134] As can be seen from Table 18, the boiling point range of the compounded organic amine neutralizer is most suitable for the atmospheric and vacuum overhead process conditions, and its base value is most suitable for neutralizing acidic substances at the overhead position of the atmospheric and vacuum tower.

[0135] 1. The boiling point range is suitable for the overhead volatile line environment

[0136] The boiling point of the neutralizer should be slightly higher than that of water, and the boiling point range should be slightly higher than the atmospheric and vacuum tower process operating temperature by 3-5°C.

[0137] No. 1 compounded organic amine neutralizer meets this requirement; No. 2 neutralizer has a slightly low boiling point and does not meet the requirement of being slightly higher than water; No. 3 neutralizer has a boiling point that is somewhat higher than that of water. No. 4 does not meet the requirement.

[0138] 2. The salt of neutralizing agent and acid must have very low melting point, insoluble in hydrocarbons

[0139] 1. The ammonium salt produced by No. 1 compounded organic amine neutralizing agent and No. 3 neutralizing agent has low melting point, meeting the requirement; the ammonium salt produced by No. 2 neutralizing agent and No. 4 ammonia has high melting point, which is easy to cause under-deposit corrosion and block the pipeline.

[0140] 3. In the overhead system, it must have uniform neutralization effect

[0141] From the pH value of the overhead, the pH value of No. 1 "three overhead water" condensate is basically stable at 6-7; the pH value of No. 2 "three overhead water" condensate is stable; the pH value of No. 3 and No. 4 "three overhead water" condensate fluctuates greatly.

[0142] 4. Strong neutralization effect and no violent reaction with hydrogen sulfide

[0143] The basicity of No. 1 compounded organic amine neutralizing agent can neutralize the acidic substances in the overhead of the atmospheric and vacuum distillation tower, and will not have violent reaction with the acidic substances.

[0144] 5. Economic and environmental protection

[0145] Because the boiling point range and basicity of No. 1 compounded organic amine neutralizing agent are suitable for the overhead system of the atmospheric and vacuum distillation tower, the addition amount of No. 1 is the least and the corrosion rate is the lowest, and the economic and environmental benefits are better than those of No. 2, No. 3 and No. 4 neutralizing agents.

[0146] Table 19 Comparison of synthetic and directly compounded organic amine neutralizing agents

[0147]

[0148] The cost of the synthetic mixed enamine and alcohol amine, which is compounded into organic amine neutralizing agent, is reduced by about 40% compared with direct compounding, and the cost can be further reduced if the raw materials are recycled; and the basicity of the synthetic compounded organic amine neutralizing agent is higher, which is beneficial to fully and effectively reduce the corrosion of the condensing system in the overhead low-temperature light oil part.

[0149] Summary: The advantages of the neutralizing agents of Examples 1-4 are as follows:

[0150] The neutralizing agent prepared by this method is mainly composed of various amines and imidazolines, has excellent neutralization effect and certain corrosion inhibition effect. The neutralizing agent is a light-colored liquid, soluble in water, with a density of 0.95-1.05 g / cm 3 , pH value > 11, and corrosion inhibition rate > 70%. It overcomes the shortcomings of traditional refinery ammonia injection in atmospheric and vacuum distillation units, and can effectively reduce the corrosion of the condensing system in the overhead low-temperature light oil part.

[0151] 1. The distillation range is suitable for the application environment of the overhead volatile line

[0152] The neutralizing agent prepared in this example is a variety of aqueous organic amine solution, and the distillation range is more suitable for the application environment of the overhead volatile line of the atmospheric-vacuum distillation unit. The main body of the sample is distilled at 110℃-150℃, and the slope of the main body part is smaller. The temperature range of the process meets the overhead volatile line environment of the atmospheric-vacuum distillation unit, especially the overhead of the atmospheric tower, which is more severely corroded. When the organic amine neutralizing agent is injected, the pH value will become stable with the change of temperature. In the gas phase upstream of the condensation zone, it is easily dissolved in water in the condensation zone, fully reacts with HCl, and the pH value does not increase or decrease significantly, which can play a full covering neutralization and corrosion prevention role in the overhead volatile line equipment.

[0153] 2. "Dew point area" is not corrosive

[0154] In the overhead oil and gas of the distillation tower, there are a large number of acidic substances. As the temperature gradually drops to the dew point area of HCl and H2S, the equipment will produce serious dew point corrosion. Because the solubility of ammonia and HCl in water is different, the solubility of ammonia decreases sharply in the dew point temperature range, while the solubility of HCl is not affected by temperature and changes little. Therefore, ammonia cannot quickly dissolve in the condensate to neutralize HCl and H2S acidic substances.

[0155] The mixed organic amine neutralizing agent is not affected by temperature and is easily dissolved in water, which can quickly dissolve in the condensate to neutralize HCl and H2S acidic substances, and the pH value of the condensate at the tower top discharge outlet is consistent with the change in the dew point area. In the process of industrial application, the dew point area corrosion of the ammonia injection device has a long history, and the dew point corrosion of the mixed organic amine neutralizing agent will be significantly reduced. The combination of mixed organic amine neutralizing agent and low-temperature corrosion inhibitor can make the corrosion rate below 0.2 mm / a.

[0156] 3. No ammonium salt scale, no plugging, no corrosion

[0157] When ammonia is injected into the overhead volatile line of the atmospheric-vacuum distillation unit of the refinery, high-melting-point (>340℃) ammonium chloride scale is generated near the dew point area, which can generate acidic ammonium bisulfide when it comes into contact with hydrogen sulfide in the oil and gas, causing secondary corrosion under the scale. The salt after the reaction of the mixed amine type neutralizing agent has a lower melting point and is quickly dissolved in water with high solubility, which does not cause corrosion under the scale and does not plug the pipeline.

[0158] 4. Stable pH value, easy to control

[0159] The pH value of the "three-top water" condensate in the overhead volatile line of the atmospheric-vacuum distillation unit injected with the neutralizing agent prepared by this method can be basically stable at 6-8 with the change of temperature, while the pH value of the condensate injected with ammonia fluctuates greatly, about 3-9, which is easy to corrode and difficult to control, as shown in Figure 1 .

[0160] ​Figure 1 It can be seen that ammonia, certain organic amines cannot effectively control in the pH 6-8 interval, and mixed organic amines can effectively control.

[0161] 5. Safe and environmentally friendly

[0162] The neutralizing agent prepared by the application can be mutually soluble with water in any proportion, the initial boiling point is greater than 100 DEG C, and compared with ammonia water, it is not easy to volatilize at room temperature, has no pungent odor, and is safer and more environmentally friendly in use environment.

[0163] 6. Certain corrosion inhibition effect

[0164] The neutralizing agent prepared by the application contains water-soluble imidazoline, which can form a firm and stable protective film on the metal surface, slow down the corrosion of pipelines and equipment, and effectively prolong the service life of the equipment and the operation period.

[0165] The injection mode of the neutralizing agent is:

[0166] a. The neutralizing agent is pumped from the raw material barrel to the neutralizing agent batching tank; b. The neutralizing agent is injected into the top system of the fractionating column by using an injection pump, and the use amount is adjusted to a relatively appropriate proportion according to the content of acidic corrosive substances in the system, so that the operating conditions of the top are stable.

[0167] The addition amount is:

[0168] When used, the product is diluted with water to about 5-10%, or can be directly injected; b. Injected into the system at 5-15 ppm.

[0169] The industrial application agent injection process is shown in Figure 2 .

[0170] After the neutralizing agent is injected into the atmospheric and vacuum unit, the following conditions can be met: under the conditions that the properties of the raw materials are basically stable, the unit is running normally, and the process operation is stable.

[0171] (1) The pH value of the overhead water is controlled to be 6-8.

[0172] (2) The neutralizing agent does not adversely affect the stability of the unit and the product quality.

[0173] (3) The neutralizing agent has no adverse effect on the subsequent device and the sewage treatment device.

[0174] (4) The injection amount of the neutralizing agent: the recommended addition amount is 5-20 ppm (relative to the amount of column feed).

[0175] In addition to being associated with the properties of the raw materials, the injection amount of the neutralizing agent can also be adjusted according to the pH value of the overhead condensate.

[0176] The present application is not limited to the specific technical solutions described in the above embodiments, and any technical solution formed by equivalent replacement is within the protection scope of the present application.

Claims

1. An organic amine neutralizing agent for use in atmospheric and vacuum distillation units, characterized in that: The steps of the synthesis method of the neutralizing agent are as follows: (1) Preparation of mixed ethyleneamine 3422.2 g of 31.0 wt% ammonia water and 1.5 g of catalyst were added to a 5000 ml high-pressure reactor. The catalyst was 2,2-bipyridine, cuprous chloride, and ferrous chloride in a mass ratio of 1:1:

1. The stirrer was kept rotating at 175 rpm. Then, 308.1 g of dichloroethane was introduced into the high-pressure reactor. The jacket heating of the high-pressure reactor was turned on at the same time. The reaction pressure was 3.5 MPa, the reaction temperature was 130 °C, and the reaction time was 30 min. After the reaction was completed, the mixture was cooled to room temperature and transferred to a rotary evaporator. The mixture was distilled and separated at -0.5 MPa and 90~175 °C to obtain 260.9 g of a mixture of ethylenediamine, piperazine, diethylenetriamine, and a small amount of triethylenetetramine. The reaction equation is as follows: ClCH2CH2Cl+NH3→ClCH=CH2+NH4Cl ClCH2CH2Cl+2NH3→NH2CH2CH2NH2•2HCl ClCH2CH2Cl+NH2CH2CH2NH2•2HCl+2NH3→NH4Cl+NH2CH2CH2NHCH2CH2NH2•3HCl ClCH2CH2Cl+NH2CH2CH2NHCH2CH2NH2•3HCl+2NH3→NH4Cl+NH2CH2CH2NHCH2CH2NHCH2CH2NH2•4HCl ClCH2CH2Cl+NH2CH2CH2NH2→C4H 10 N2•2HCl After the reaction was completed, a sample was taken, and the conversion rate of dichloroethane was determined to be 99.0% by Mohr's titration. The composition of various ethyleneamines after distillation was determined by chromatography, and the contents were: ethylenediamine 59.9 wt%, diethylenetriamine 13.0 wt%, triethylenetetramine 3.7 wt%, and piperazine 6.8 wt%. (2) Preparation of mixed ethanolamines Add 435.1g of 22.0wt% ammonia water to a 2000ml high-pressure reactor and keep the stirrer rotating at 175rpm. Then, introduce 124.7g of ethylene oxide (EO) into the high-pressure reactor. The reaction temperature is 44℃, the reaction pressure is 0.1~0.3MPa, and the reaction time is 60min. After the above reaction was completed, 650.1 g of 40 wt% methylamine aqueous solution was added to the high-pressure reactor; the stirrer was kept rotating at 175 rpm, and then the temperature was raised to 130℃. Then, 131.0 g of ethylene oxide (EO) was slowly introduced into the high-pressure reactor at a reaction pressure of 2.5 MPa and a reaction time of 30 min. After the reaction was completed, the mixture of monoethanolamine (MEA), N-methylmonoethanolamine (MMEA), and N-methyldiethanolamine (MDEA) was separated by vacuum distillation using a rotary evaporator at -0.5 MPa and 115~210℃ to obtain 470.8 g of a mixture of monoethanolamine (MEA), N-methylmonoethanolamine (MMEA), and N-methyldiethanolamine (MDEA). The reaction equation is as follows: NH3 + C2H4O → H2NCH2CH2OH H2NCH2CH2OH+C2H4O→HN(CH2CH2OH)2 HN(CH2CH2OH)2+C2H4O→N(CH2CH2OH)3 CH3NH2 + C2H4O → CH3NHCH2CH2OH CH3NH2+2C2H4O→CH3N(CH2CH2OH)2 After the reaction was completed, a sample was taken, and the conversion rate of EO was determined to be 98.2% using the Volhard method. The composition of various ethanolamines after distillation was determined by chromatography, and the contents were: MEA 54.9 wt%, diethanolamine DEA 5.9 wt%, MMEA 18.9 wt%, and MDEA 14.9 wt%. (3) Mixed organic amine compound Add 200.0g of the mixed ethyleneamine and 100.0g of the mixed ethanolamine prepared in the above steps to a 500ml beaker, mix with a certain amount of water, stir evenly to obtain a mixed solution of 497.5g of multi-component organic amines, then add 2.5g of water-soluble imidazoline, stir evenly again to obtain the mixed organic amine neutralizer product.

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