CN108017666B

CN108017666B - Phosphate amine salt natural gas drag reducer and preparation method and application thereof

Info

Publication number: CN108017666B
Application number: CN201610965436.3A
Authority: CN
Inventors: 赵巍; 王晓霖; 李遵照; 陈建磊
Original assignee: China Petroleum and Chemical Corp; Sinopec Fushun Research Institute of Petroleum and Petrochemicals
Current assignee: China Petroleum and Chemical Corp; Sinopec Fushun Research Institute of Petroleum and Petrochemicals
Priority date: 2016-11-01
Filing date: 2016-11-01
Publication date: 2021-03-05
Anticipated expiration: 2036-11-01
Also published as: CN108017666A

Abstract

The invention discloses a phosphoric acid amine salt natural gas drag reducer. The molecular structural formula is as follows:

. The drag reducer is prepared by the following method: dissolving diester phosphate in a solvent, dropwise adding diamine at the temperature of 20-50 ℃, reacting for 2-4 h at the temperature of 20-50 ℃, heating to react for 6-15 h at the temperature of 60-100 ℃, and removing the solvent after the reaction is finished to obtain the product. The drag reducer provided by the invention has a multi-polar end and a multi-nonpolar end, and has good adsorption performance and excellent drag reduction and delivery increase effects. The invention has the advantages of simple synthesis process, mild condition, short time, low requirement on equipment and easy realization of large-scale industrial production.

Description

Phosphate amine salt natural gas drag reducer and preparation method and application thereof

Technical Field

The invention belongs to the field of organic chemistry, and particularly relates to a phosphate amine salt natural gas drag reducer as well as a preparation method and application thereof.

Background

As an efficient and clean energy source, natural gas has become the best choice for improving the environment and promoting the sustainable development of economy in all countries of the world, and the demand of natural gas is increasing day by day.

At present, the main transportation mode of natural gas is pipeline transportation. However, in the process of transporting natural gas by a pipe, the roughness of the inner wall of the pipe can generate frictional resistance, so that gas vortex is generated, and the pressure drop along the way and the energy loss are caused. Therefore, to increase the gas transportation amount, it is necessary to reduce the resistance during the transportation of the natural gas and reduce the energy loss. At present, the main methods for reducing drag and increasing delivery are an inner coating drag reduction technology and a drag reducer drag reduction technology. The natural gas drag reducer can obviously increase the output, save energy, reduce consumption, meet the seasonal peak load regulation of in-service pipelines, improve the operation safety factors of full-load operation pipelines and corrosion aging pipelines, and the like. The natural gas drag reducer has great economic value and application potential, and has good actual production demand and market prospect.

The natural gas drag reducer is a compound similar to a surfactant structure, has a polar end and a non-polar end, after the natural gas drag reducer is filled into a pipeline, the polar end is adsorbed on the inner wall of the pipeline through a coordination bond, and the non-polar end exists between a fluid and the inner surface of the pipeline and is suspended in an airflow in a downstream direction under the action of shear stress to form a layer of film. The film can partially fill the depressions on the wall surface of the tube, and serves to reduce roughness. Meanwhile, in the process of recovering and extending the molecules, part of energy of the fluid molecules impacting the inner wall is absorbed and returned to the fluid, the radial pulsation of the gas and the pulsation generated by the rough bulges are reduced, and the vortex energy is reduced, so that the flow resistance is reduced, and the aim of reducing the resistance is fulfilled. Therefore, the development of natural gas drag reducers with strong polar-end adsorptivity and moderate flexible-end has become one of the active petrochemical additive fields in recent years.

US 5902784A and Chinese patent CN 101575495A respectively disclose a synthetic method of a nitrogen-containing natural gas drag reducer, and the nitrogen-containing natural gas drag reducer is used for drag reduction and transportation increase of a gas pipeline. CN 102040908A discloses that trimethoxy silane and alpha-dodecene are used as raw materials to synthesize dodecyl trimethoxy silane drag reducer in the presence of platinum catalyst. The Mannich alkali type drag reducer synthesized by the patent CN 101328442A through a two-step method can be applied to drag reduction and transportation increase of natural gas gathering and transportation pipelines.

In addition, there are some reports on the synthesis of nitrogen-containing drag reducers, such as patent CN 102838606 a also discloses the preparation of a porphyrin-based natural gas drag reducer, and patent CN 101575497 a; US 5549848A; CN 101328441A; CN 101329011A; w.g. Xing et al (polymer. degrad. stab. 2011, 92: 74-78); asahi et al (Natural gas industry 2010, 30: 92-96). Patents CN 102443022A and CN 102863473 a report phosphorous drag reducers octadecyl alcohol phosphate ammonium salts and six-membered cycloalkyl siloxane-phosphate esters, respectively. However, the natural gas drag reducers reported in these patents and documents have some disadvantages, mainly including single polar end, weak adsorptivity, few nonpolar ends (such as octadecyl alcohol phosphate ammonium salts), unobvious drag reduction effect, and poor solubility (such as hexa-membered cyclic alkyl siloxane-phosphate), which cannot be applied to natural gas pipeline drag reduction in large scale, so the application range is greatly limited, and the drag reduction effect needs to be further improved.

Disclosure of Invention

Aiming at the defects of poor adsorptivity, few polar chain ends and few non-polar ends and poor drag reduction effect of the existing natural gas drag reduction agent, the invention provides the phosphate amine salt natural gas drag reduction agent and the preparation method thereof. The drag reducer has the characteristics of strong adsorption of a plurality of polar ends and good drag reduction effect of a plurality of nonpolar ends. The preparation method is simple, the reaction time is short, and the solvent is low in toxicity and pollution-free.

The invention provides a phosphate amine salt drag reducer, the molecular structural formula of which is shown as the formula (I):

formula (I);

in the formula (I), R₁Is C₄-C₁₆Any of the aliphatic chains, R₂Is C₄-C₁₆An aliphatic chain or an aromatic hydrocarbon.

The invention also provides a preparation method of the phosphate amine salt drag reducer, which comprises the following steps:

dissolving a phosphoric acid diester in a solvent, dropwise adding diamine at 20-50 ℃, reacting for 2-4 h at 20-50 ℃, heating to 60-100 ℃, reacting for 6-15 h, and removing the solvent after the reaction is finished to obtain the phosphoric acid amine salt drag reducer.

In the method, the molar ratio of the diester phosphate to the diamine is 2: 1-3: 1, preferably 2: 1-2.5: 1.

in the method, the solvent is one or more of methanol, ethanol and toluene, and ethanol is preferred.

In the method of the invention, the diamine is C₄-C₁₆One of aliphatic chain diamine or aromatic diamine with the structural formula of H₂NR₂NH₂(ii) a Wherein R is₂Is C₄-C₁₆Aliphatic chains or aromatic hydrocarbons. The phosphoric acid diester is C₄-C₁₆Any one of aliphatic chain phosphodiesters.

In the method, the heating rate is generally 1-20 ℃/h, preferably 1-10 ℃/h.

The preparation route of the drag reducer provided by the invention is as follows:

。

the invention also provides an application (use) of the synthesized natural gas drag reducer in natural gas pipeline transportation. The drag reducer can reduce gas transmission power, improve gas transmission capacity, meet the requirement of seasonal peak shaving in the natural gas pipeline transmission, and simultaneously can reduce the danger of full-load operation to a certain extent. Besides, the synthesized drag reducer has the auxiliary functions of corrosion inhibition, internal coating repair and the like.

The product of the invention is used as a natural gas drag reducer, and is generally prepared into solutions of ethanol, gasoline, diesel oil or acetone and the like to be applied to drag reduction and transportation increase of natural gas pipelines. The concentration of the drag reducer in the prepared solution is 5-200 g/L.

Besides, the product of the invention also has a certain corrosion inhibition function on the natural gas pipeline.

1. The phosphate amine salt natural gas drag reducer is a compound with a multi-polar end and a multi-nonpolar end, is used as a drag reduction additive of a natural gas pipeline, is atomized and injected or coated on the inner wall of the pipeline, the polar end of the compound is firmly adsorbed on the inner surface of the pipeline metal, and forms a smooth film, the nonpolar end exists between the pipeline fluid and the inner surface, part of the compound fills the depression of the inner surface of the pipeline, reduces the roughness, the nonpolar end is suspended in the airflow in a downstream direction under the action of shear stress, part of the energy of impacting inner wall fluid molecules is absorbed and returned to the fluid in the process of molecular recovery and extension, the radial pulsation of the gas and the pulsation generated by rough protrusions are reduced, the vortex energy is reduced, and the compound has good adsorption performance and excellent drag reduction and delivery effects on the metal surface.

2. In the preparation method of the drag reducer, two temperature sections of 20-50 ℃ and 60-100 ℃ are particularly selected and arranged. Since 1 mole of diamine is reacted with 2 moles of phosphoric acid, the diamine is added dropwise and reacted at a relatively low temperature to control the reaction and avoid the generation of by-products due to an excessively high temperature. After a period of reaction time, the temperature is raised and the reaction is continued in order to promote the reaction to be complete and avoid the diamine of the final product being only connected with phosphate at one end. In general, in order to promote the reaction to be complete, the reaction temperature is adjusted, i.e., the reaction temperature is appropriately raised, or the reaction time is prolonged. However, the efficiency is low only by prolonging the reaction time, and the proportion of raw materials is increased, because of the reaction, some raw materials are lost, but the by-products are increased when the proportion is too large. The method can prepare the drag reducer product with the two ends connected with the phosphate ester, and improves the service performance of the drag reducer.

3. The preparation method disclosed by the invention is simple in preparation process, mild in reaction condition, short in reaction time, low in equipment requirement, easy to realize large-scale industrial production, and meanwhile overcomes the defects of poor adsorptivity and short duration of drag reduction effect of the existing natural gas drag reducer.

Drawings

FIG. 1 is a surface SEM of a drag reducer-treated steel sheet obtained in example 1. Wherein, (a) a blank steel surface; (b) the steel surface after film forming; (c) and (5) treating the surface of the steel by using the condensate.

Fig. 2 is an electrochemical impedance spectrum of a white iron electrode and an iron electrode after film formation using the drag reducer obtained in example 1.

Fig. 3 is an electrochemical polarization curve of the electrode and the blank electrode after the film formation of the drag reducer in example 1.

Detailed Description

The amine phosphate salt natural gas drag reducer of the present invention and the process for its preparation are further illustrated by the following specific examples, which are provided by way of illustration only and are not intended to be limiting of the present invention.

In the examples, a FEI QUANTA-200 (Eindhoven, Netherlands) type scanning electron microscope was used to perform scanning test on the soaked sample, and the acceleration voltage was 15 kV; performing electrochemical test and data analysis on the tested sample by using an IM6 electrochemical workstation of Germany ZAHZER company; the used indoor loop test evaluation device is a self-made test device.

Example 1

161.2g of diisooctyl phosphate and 500mL of ethanol were put into a 1000mL four-necked flask equipped with a reflux condenser, a thermometer, a stirrer and a constant pressure dropping funnel, and 15.0g of ethylenediamine was slowly dropped while stirring, and the temperature of the system was controlled to be not more than 30 ℃. After dropping, the system is slowly heated to 40 ℃ for reaction for 3 h. The temperature is increased to 70 ℃ for reaction for 6 h. After the reaction was completed, ethanol was removed under reduced pressure to obtain a pale yellow viscous liquid.

The structural formula of the product obtained in this embodiment is as follows:

。

and (5) testing film forming property and stability. FIG. 1 shows an SEM of the surface of a blank steel sheet and a steel sheet after spraying a drag reducer. As can be seen from the figure, the blank sheet has a deeper surface indentation and a greater roughness, and the gas flowing through its surface is affected by a greater resistance (FIG. 1-a). The indentations on the surface of the steel sheet (fig. 1-b) after the drag reducer coating are filled more uniformly with the product. The drag reducer forms a layer of compact protective film on the surface of the steel sheet, so that the surface of the steel sheet becomes smoother, and the roughness of the steel sheet is greatly reduced. The experimental result shows that the product has good film-forming property on the steel surface and has the properties required by the natural gas drag reducer. FIG. 1-c shows SEM images of the experimental back surface of the film-formed steel sheet in the configured simulated condensate. It can be seen that the steel sheet surface treated with the condensate had some dimples visible, but the roughness was still reduced compared to the blank sheet, and a certain amount of the drag reducing agent product was still adsorbed in the dimples. The experimental result shows that although the roughness of the steel sheet is increased compared with that of a sample which is not subjected to suspected liquid system scouring after the steel sheet is stirred in the simulated condensate liquid for 30 days, the drag reducer has no obvious chemical change in the simulated condensate liquid system, and the synthesized drag reducer still has good film forming stability on the surface of the steel sheet.

And (4) performing electrochemical test. The iron electrode (Q235) was encapsulated with epoxy, exposing only the tip to contact the solution. Before each experiment, the surface of the iron electrode is polished to a mirror surface by using No. 2000 abrasive paper, washed by water and ethanol, naturally dried, sprayed with 20g/L of prepared drag reducer ethanol solution, and naturally dried. A three-chamber electrolytic cell is adopted, a working electrode is an iron electrode, a reference electrode is a saturated calomel electrode, a platinum electrode is an auxiliary electrode, a sine perturbation signal with the amplitude of 5mV is selected, the sine perturbation signal is scanned from high frequency to low frequency within the frequency range of 0.02Hz-60kHz, and electrochemical impedance spectroscopy test is carried out in 3.5% NaCl solution. The film forming property of the drag reducer on the surface of the steel is tested by electrochemical impedance spectroscopy.

FIG. 2 is the electrochemical impedance spectrum of the blank iron electrode and the iron electrode after film formation. The literature reports that the charge transfer resistance of the film is increased, and the capacitive arc is also increased, so that the higher the low-frequency arc is, the better the barrier effect of the film on the surface electrode process and the film forming effect on the iron electrode are. Because the iron electrode is in a semicircular capacitive arc resistance in a low-frequency area, the electrochemical reaction process of the surface of the iron electrode is mainly controlled by a charge transfer process. As can be seen from fig. 2, the blank sample has a smaller capacitive arc resistance, indicating that the blocking effect of the iron electrode without film formation is smaller. After the film of the drag reducer is formed on the surface of the iron electrode, two continuous capacitive arcs are formed from a high frequency area to a low frequency area. The smaller capacitive arc is formed in a high-frequency area and is the capacitive arc of film formation of the drag reducer, which shows that the drag reducer forms a barrier film on the surface of an iron electrode, and then forms a larger capacitive arc in a low-frequency area, and is the capacitive arc of the iron electrode after film formation, and the diameter of the capacitive arc is larger than that of a blank iron electrode.

Fig. 3 and table 1 show the electrochemical polarization curve test results after film formation of the blank electrode and the drag reducer. From the results, it can be seen that the change of the cathodic polarization curve is not obvious compared with the blank iron electrode, the anodic polarization curve becomes steep under the protection of the drag reducer, the self-corrosion potential value is increased from-0.644V to-0.508V and is increased by 0.136V, and the logarithmic value of the self-corrosion current is reduced from-4.87 lgA to-5.23 lgA and is reduced by 0.36 lgA. The electrochemical polarization curve test result shows that the drag reducer can form a stable protective film on the surface of the iron electrode to block the interaction between the electrode and the test solution, so that the iron electrode is more stable, the self-corrosion potential is increased, and the self-corrosion current is reduced. The film forming process of the synthesized drag reducer belongs to an anode control type, and a product forms a film on the surface of an anode.

Table 1 electrochemical polarization test results of the electrodes and blank electrodes after film formation.

Sample (I)	Self-corroding potential (V)	Self-corrosion current logarithm (lgA)
			Hollow white iron electrode	-0.644	-4.87
Electrode after film formation	-0.508	-5.23

Indoor loop test analysis shows that the product is prepared into ethanol solution, atomized and injected into a loop, the test pressure is 0.5-0.6MPa, when the concentration of the drag reducer is 20g/L, the average drag reduction rate can reach 10.2%, and the effective period is more than 60 days.

Example 2

105.1g of di-n-butyl phosphate and 500mL of ethanol were put into a 1000mL four-necked flask equipped with a reflux condenser, a thermometer, a stirrer and a constant pressure dropping funnel, and a 100mL ethanol solution of 21.5g of anhydrous piperazine was slowly dropped while stirring, with the system temperature being controlled not to exceed 30 ℃. After dropping, the system is slowly heated to 40 ℃ for reaction for 4 h. The temperature is increased to 70 ℃ for reaction for 7 h. After the reaction was completed, ethanol was removed under reduced pressure to obtain a pale yellow viscous liquid.

。

indoor loop test analysis shows that the product is prepared into ethanol solution, atomized and injected into a loop, the test pressure is 0.5-0.6MPa, when the concentration of the drag reducer is 300g/L, the average drag reduction rate can reach 9.7%, and the effective period is more than 60 days.

Example 3

273.4g of dicetyl phosphate and 500mL of ethanol were put into a 1000mL four-necked flask equipped with a reflux condenser, a thermometer, a stirrer and a constant pressure dropping funnel, and 32.3g of di-n-butylamine was slowly dropped under stirring while controlling the temperature of the system to not more than 30 ℃. After dropping, the system is slowly heated to 40 ℃ for reaction for 4 h. The temperature is increased to 70 ℃ for reaction for 10 h. After the reaction was completed, ethanol was removed under reduced pressure to obtain a yellow viscous liquid.

。

indoor loop test analysis shows that the product is prepared into ethanol solution, atomized and injected into a loop, the test pressure is 0.5-0.6MPa, when the concentration of the drag reducer is 200g/L, the average drag reduction rate can reach 8.1%, and the effective period is more than 60 days.

Example 4

118.6g of diisoamyl phosphate and 500mL of ethanol are placed in a 1000mL four-necked flask equipped with a reflux condenser, a thermometer, a stirrer and a constant pressure dropping funnel, and a solution of 27.0g of p-phenylenediamine in 100mL of ethanol is slowly dropped while stirring, and the temperature of the system is controlled to be not more than 30 ℃. After dropping, the system is slowly heated to 50 ℃ to react for 6 h. The temperature is increased to 80 ℃ for reaction for 15 h. After the reaction was completed, ethanol was removed under reduced pressure to obtain a yellow viscous liquid.

。

indoor loop test analysis shows that the product is prepared into ethanol solution, atomized and injected into a loop, the test pressure is 0.5-0.6MPa, when the concentration of the drag reducer is 20g/L, the average drag reduction rate can reach 7.6%, and the effective period is more than 60 days.

Example 5

The solvent used in step one of this embodiment is 500mL of methanol, and the rest is the same as in example 1.

Example 6

The solvent used in step one of this embodiment is 500mL of toluene, and the rest is the same as in example 1.

Claims

1. The molecular structural formula of the phosphate amine salt natural gas drag reducer is shown as the formula (I):

or

Formula (I).

2. Use of the phosphate amine salt natural gas drag reducer of claim 1 in natural gas pipeline transportation.

3. The use according to claim 2, wherein the phosphate amine salt natural gas drag reducing agent is formulated for use as an ethanol, gasoline, diesel or acetone solution.

4. The use according to claim 3, wherein the content of the phosphate amine salt natural gas drag reducer in the prepared solution is 5-200 g/L.