CN104194756B - Novel hydrate kinetic inhibitor as well as preparation method and applications thereof - Google Patents

Abstract

The invention discloses a novel hydrate kinetics inhibitor and its preparation method and application. The preparation method comprises: dissolving monomers in a solvent, adding an initiator to initiate solution polymerization, and obtaining a novel hydrate kinetics inhibitor The main component of the inhibitor is a polyhydroxy polymer; the monomer is obtained by reacting chlorophenol with N-vinylcaprolactam or N-vinylpyrrolidone. The inhibitor of the present invention has the effect of compound use of other inhibitors and alcohols, can withstand lower supercooling, can make the hydrate formation induction time longer, and improve the inhibitory effect of the hydrate inhibitor, with high efficiency, low Dosage, wide applicability and other advantages.

Description

A novel hydrate kinetic inhibitor and its preparation method and application

technical field

The invention relates to the technical field of oil and gas hydrates, in particular to a novel hydrate kinetics inhibitor and a preparation method and application thereof.

Background technique

During the pipeline transportation of oil and natural gas, due to the existence of low temperature and high pressure, the low boiling point hydrocarbon gases (CH4, C2H6, C3H8, etc.) form gas hydrates. The generated hydrates will block the pipes and valves in severe cases, resulting in pipe bursts and instrument damage. For offshore oil and gas field development and submarine pipeline transportation, the problem of hydrate formation is particularly prominent, because the seabed temperature is low and the pressure is high, which is very suitable for the formation of hydrates. For example, under a pressure of about 1 MPa, ethane can form hydrates at a temperature lower than 4°C, and at a pressure of 3 MPa, ethane can form hydrates at a temperature lower than 14°C. Therefore, seeking effective inhibitors to inhibit the formation of hydrates has become a major concern of scientists in the oil and gas industry.

The current industrial inhibition of hydrate formation mainly reduces the conditions for hydrate formation by adding chemical additives. The traditional additives are mainly thermodynamic inhibitors, including methanol, ethylene glycol and other alcohols or electrolytes to change the equilibrium conditions of hydrates, but the use of thermodynamic inhibitors requires a large demand and high cost, and at the same time, the loss of inhibitors is also large and leads to damage. Therefore, seeking new low-dose and environmentally friendly hydrate inhibitors has become the research focus of current scientists.

Low-dose inhibitors, including kinetic inhibitors and anti-aggregation agents. The addition of kinetic inhibitors can inhibit or delay the growth time of hydrate, so as to achieve the purpose of inhibiting hydrate formation. Its addition concentration is low, does not affect the thermodynamic conditions of hydrate formation, and can delay the nucleation and crystal growth time of hydrates under the thermodynamic conditions of hydrate formation. The anti-aggregation agent is to prevent the aggregation of hydrate crystal grains by adding some low-concentration surfactants or polymers to ensure the safe delivery of fluids.

Currently known inhibitors to inhibit hydrate formation are mostly alcohol complex inhibitors.

Contents of the invention

The object of the present invention is to provide a novel hydrate kinetics inhibitor and its preparation method; the inhibitor is a polyhydroxy polymer with strong solubility and less dosage, and is suitable for oil-gas-water three-phase system, oil-water or gas Water two-phase coexistence system.

A novel hydrate kinetic inhibitor has one of the following structures:

Where n=40-300.

A preparation method of a novel hydrate kinetics inhibitor. Dissolve monomers in a solvent, add an initiator to initiate solution polymerization, and obtain a novel hydrate kinetics inhibitor. The main component of the inhibitor is a polyhydroxy polymer; The above-mentioned monomer is obtained by reacting chlorophenol with N-vinyl caprolactam or N-vinyl pyrrolidone.

In the above preparation method, the monomers include 1-[(2-hydroxyphenyl)vinyl]caprolactam, 1-[(2-dihydroxyphenyl)vinyl]caprolactam, 1-[(2-trihydroxyphenyl) yl)vinyl]caprolactam, 1-[(2-hydroxyphenyl)vinyl]pyrrolidone, 1-[(2-dihydroxyphenyl)vinyl]pyrrolidone or 1-[(2-trihydroxyphenyl)ethylene Base] pyrrolidone.

In the above preparation method, the chlorophenol is p-chlorophenol, m-chlorophenol, o-chlorophenol, chloroquinone or chloroglucinol.

In the above preparation method, the solvent includes soluble alcohols or soluble ethers.

In the above preparation method, the volume ratio of the monomer used to synthesize the inhibitor to the solvent is 1:3-4:1.

In the above preparation method, the amount of the initiator used in synthesizing the polymer accounts for 0.3wt%-1.5wt% of the solvent used, the reaction temperature is 40-150° C., and the reaction time is 2-12 hours.

In the above preparation method, the average molecular weight M _w of the hydroxyl polymer is 50,000-300,000.

A new type of hydrate kinetic inhibitor is applied to the formation of hydrate in oil-gas-water three-phase system, oil-water or gas-water two-phase system.

In the above application, when the inhibitor is used, it is prepared into an aqueous solution first, and the concentration of the aqueous solution is 0.1wt%-5wt%.

The mass ratio of novel hydrate inhibitor (poly 1-(4-hydroxystyrene) caprolactam or poly 1-(4-hydroxystyrene) pyrrolidone) to water in the system can be in the range of 0.1%-15% provided by the present invention internal regulation. Its use concentration should be comprehensively considered according to specific conditions such as site conditions and economy.

The applicable pressure of the inhibitor is 1-25MPa, and the temperature is -25-25°C.

The molecular weight of the inhibitor is 50000-300000.

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

As a kinetic inhibitor polymer, the monomer of the present invention has a hydroxyl group, so the inhibitor can be used alone without compounding with alcohols, and overcomes the disadvantages of large dosage and high cost of thermodynamic inhibitors. At the same time, due to more hydroxyl groups, the polymer has good water solubility, can prolong the formation time of hydrates, reduce the formation amount of hydrates, and has wide applicability and good biodegradability. Typical kinetic inhibitors such as polyvinyl caprolactam (PVCap) and polyvinylpyrrolidone (PVP) contain amide groups (-N-C=O), and amide groups are inserted into the water phase as the ring where the hydrophilic group is located, forming hydrogen bonds to exert The benzene ring is far away from the water phase due to its hydrophobicity, but the appearance of the hydroxyl group on the phenol ring becomes hydrophilic, so that the entire additive is inserted into the water phase and away from the methane phase, thereby exerting an inhibitory effect.

detailed description

The present invention will be further described in detail below in conjunction with specific examples, but the embodiments of the present invention are not limited thereto, and for process parameters not specifically indicated, conventional techniques can be referred to.

Example 1

Preparation of Poly 1-(4-Hydroxystyrene) Caprolactam Homopolymer

Mix 20 grams of p-chlorophenol monomer and 0.3 grams of N-vinylcaprolactam monomer in a glass tube, use palladium as a catalyst, heat up to 60 ° C, keep the temperature for 4 hours, cool to room temperature, and then filter and distill the product to obtain 1-(hydroxystyryl) caprolactam monomer is obtained. Mix the obtained monomer 1-(hydroxystyryl)caprolactam and diethyl ether at a volume ratio of 1:1, and add azobisisobutyronitrile dropwise at 100°C with a concentration of 1.0wt% to initiate solution polymerization, and the reaction time is 6 hours , to obtain poly 1-(4-hydroxystyrene) caprolactam homopolymer.

The inhibitor described in the following examples was tested using the product obtained in Example 1, and the weight average molecular weight of the inhibitor was 300,000.

The experimental platform used in the following examples is described as follows:

The present invention adopts a visual hydrate reaction system with an external jacket with double windows and a magnetic stirrer as the experimental equipment. , vacuum pump and data acquisition instrument. The low temperature constant temperature bath can provide -30~100℃ refrigerant circulating fluid for the jacket of the reactor. Under the magnetic stirring, the hydrate can be formed in the high pressure reactor, and the formation of hydrate in the reactor can be observed through the window. The temperature and pressure data during the hydration process can be transmitted to the computer through the pressure stabilization sensor and data acquisition instrument. The working pressure of the system is 0~25MPa, and the working temperature is -30~100℃. The inhibitory effect of the new hydrate inhibitor on the hydrate formation in the reactor can be measured by the hydrate induced formation time and complete formation time. The longer the hydrate induction time and the longer the hydrate complete formation time, the better the inhibitor effect.

The initial temperature of the reaction is set at 1°C, a mixed gas of methane, ethane and propane is introduced, and the initial pressure is set at a fixed value assuming 9MPa.

The formation of hydrate is judged by the pressure change in the reactor. Before the reaction starts, the pressure in the reactor is always maintained at 9MPa. After the reaction starts, the point where the pressure in the reactor suddenly drops is the starting point of hydrate formation. Hydrate induction time is the time elapsed from the time when gas is introduced into the kettle and the pressure is kept constant at 9MPa to the point of pressure drop. The complete hydrate formation time is the time elapsed from the time when gas is introduced into the reactor and the pressure is kept constant at 9MPa to the reaction equilibrium. The effect of the inhibitor of the present invention can be judged according to the induction time and complete formation time of the hydrate.

Before the reaction started, the reaction kettle was cleaned with deionized water, and after vacuum drying, 150 mL of deionized aqueous solution containing poly 1-(4-hydroxystyrene) caprolactam with a certain concentration was added, and after the temperature in the reaction kettle was stabilized at a certain value, the Add (CH ₄ 92.05%, C ₂ H ₆ 5.05%, C ₃ H ₈ 2.90% (volume content)), increase the pressure to a certain value, stir with a magnetic stirrer, and after the reaction reaches equilibrium, hydrate The thing is fully formed.

Example 2

Based on the quality of water, add 150mL of deionized water into the reactor, and wait until the temperature in the reactor is stabilized at 1°C, and then feed gas (CH ₄ 92.05%, C ₂ H ₆ 5.05%, C ₃ H ₈ 2.90%), so that The pressure is 3MPa, the reaction reaches equilibrium, and the amount of methane gas consumed is reflected by the pressure drop. The results show that the induction time required for hydrate formation is 43 minutes, and the complete hydrate formation time is 151 minutes. Prepare 150 mL of an aqueous solution of poly-1-( ₄ -hydroxystyrene) caprolactam ( _PHAO ) with a mass concentration of 0.1% and put it into a reaction kettle. The temperature in the kettle is stabilized at about ₁ °C. 5.05%, C ₃ H ₈ 2.90%), the pressure was stabilized at 3MPa, and the reaction reached equilibrium. The results showed that the induction time required for hydrate formation was 139min, and the complete hydrate formation time was 380min.

Example 3

Based on the quality of water, add 150mL of deionized water into the reactor, and wait until the temperature in the reactor is stabilized at 1°C, and then feed gas (CH ₄ 92.05%, C ₂ H ₆ 5.05%, C ₃ H ₈ 2.90%), so that The pressure is 9MPa, the reaction reaches equilibrium, and the amount of methane gas consumed is reflected by the pressure drop. The results show that the induction time required for hydrate formation is 35 minutes, and the complete hydrate formation time is 140 minutes. Prepare 150 mL of an aqueous solution of poly 1-( ₄ -hydroxystyrene) caprolactam ( _PHAO ) with a mass concentration of 0.3% and put it into a reaction kettle. The temperature in the kettle is stabilized at about ₁ °C. 5.05%, C ₃ H ₈ 2.90%), the pressure was stabilized at 9MPa, and the reaction reached equilibrium. The results showed that the induction time required for hydrate formation was 55min, and the complete formation time of hydrate was 210min.

Example 4

Based on the quality of water, add 150mL of deionized water into the reactor, and wait until the temperature in the reactor is stabilized at 5°C, and feed gas (CH ₄ 92.05%, C ₂ H ₆ 5.05%, C ₃ H ₈ 2.90%), so that The pressure is 12MPa, and the reaction reaches equilibrium. The results show that the induction time required for hydrate formation is 33 minutes, and the complete formation time of hydrate is 145 minutes. Prepare 150 mL of an aqueous solution of poly-1-( ₄ -hydroxystyrene) caprolactam (PHAO) with a mass concentration of ₁ % and put it into a reaction kettle. The temperature in the kettle is stabilized at about ₅ °C. 5.05%, C ₃ H ₈ 2.90%), the pressure was stabilized at 12MPa, and the reaction reached equilibrium. The results showed that the induction time required for hydrate formation was 86min, and the complete hydrate formation time was 340min.

Example 5

Based on the quality of water, add 150mL of deionized water into the reactor, and wait until the temperature in the reactor is stabilized at 3°C, and then feed gas (CH ₄ 92.05%, C ₂ H ₆ 5.05%, C ₃ H ₈ 2.90%), so that The pressure is 6MPa, and the reaction reaches equilibrium. The results show that the induction time required for hydrate formation is 48 minutes, and the complete formation time of hydrate is 135 minutes. Prepare 150 mL of an aqueous solution of poly-1-( ₄ -hydroxystyrene) caprolactam (PHAO) with a mass concentration of ₅ % and put it into a reaction kettle. The temperature in the kettle is stabilized at about ₃ °C. 5.05%, C ₃ H ₈ 2.90%), the pressure was stabilized at 6MPa, and the reaction reached equilibrium. The results showed that the induction time required for hydrate formation was 232min, and the complete hydrate formation time was 732min.

Example 6

Based on the quality of water, add 150mL deionized water into the reactor, and wait until the temperature in the reactor is stabilized at 6°C, and then feed gas (CH ₄ 92.05%, C ₂ H ₆ 5.05%, C ₃ H ₈ 2.90%), so that The pressure is 18MPa, and the reaction reaches equilibrium. The results show that the induction time required for hydrate formation is 29 minutes, and the complete formation time of hydrate is 170 minutes. Prepare 150 mL of an aqueous solution of poly-1-( ₄ -hydroxystyrene) caprolactam (PHAO) with a mass concentration of ₃ % and put it into a reaction kettle. The temperature in the kettle is stabilized at about ₆ °C. 5.05%, C ₃ H ₈ 2.90%), the pressure was stabilized at 18MPa, and the reaction reached equilibrium. The results showed that the induction time required for hydrate formation was 85min, and the complete hydrate formation time was 367min.

Example 7

Based on the quality of water, add 150mL of deionized water to the reactor, and wait until the temperature in the reactor is stabilized at 10°C, and then feed gas (CH ₄ 92.05%, C ₂ H ₆ 5.05%, C ₃ H ₈ 2.90%), so that The pressure is 25MPa, and the reaction reaches equilibrium. The results show that the induction time required for hydrate formation is 18 minutes, and the complete formation time of hydrate is 165 minutes. Prepare 150 mL of an aqueous solution of poly-1-( ₄ -hydroxystyrene) caprolactam (PHAO) with a mass concentration of ₁₀ % and put it into a reaction kettle. The temperature in the kettle is stabilized at about ₁₀ °C. 5.05%, C ₃ H ₈ 2.90%), the pressure was stabilized at 25MPa, and the reaction reached equilibrium. The results showed that the induction time required for hydrate formation was 225min, and the complete hydrate formation time was 689min.

Example 8

Based on the quality of water, add 150mL of deionized water to the reactor, and when the temperature in the reactor is stabilized at 15°C, gas (CH ₄ 92.05%, C ₂ H ₆ 5.05%, C ₃ H ₈ 2.90%) is introduced, so that The pressure is 25MPa, and the reaction reaches equilibrium. The results show that the induction time required for hydrate formation is 23 minutes, and the complete formation time of hydrate is 174 minutes. Prepare 150 mL of an aqueous solution of poly-1-( ₄ -hydroxystyrene) caprolactam (PHAO) with a mass concentration of ₁₅ % and put it into a reaction kettle. The temperature in the kettle is stabilized at about ₁₅ °C. 5.05%, C ₃ H ₈ 2.90%), the pressure was stabilized at 25MPa, and the reaction reached equilibrium. The results showed that the induction time required for hydrate formation was 338min, and the complete hydrate formation time was 1013min.

It can be seen from the above examples that when the mass concentration of the inhibitor is 5%, the temperature in the kettle is 3°C, and the pressure is stable at 6Mpa, it has an obvious inhibitory effect on the formation of gas hydrate and is the most economical.

The above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, rather than limiting the implementation of the present invention. For those of ordinary skill in the art, other changes or changes in different forms can be made on the basis of the above description. It is not necessary and impossible to exhaustively list all the implementation manners here. All modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the claims of the present invention.

Claims (3)

1. a kind of novel hydrates kinetic inhibitor is it is characterised in that have one of following structure：

The preparation method of described inhibitor is that monomer is dissolved in solvent, adds initiator to cause polymerisation in solution, obtains a kind of new Type hydrate dynamic inhibitor；Described monomer is reacted with N caprolactam or N vinyl pyrrolidone by chlorophenol Gained；

Described chlorophenol is parachlorophenol, chlorobenzene diphenol or chlorobenzene triphenol；

During synthetic polymer, initiator amount accounts for the 0.3wt%～1.5wt% of solvent load, and reaction temperature is 40～150 DEG C, instead It is 2～12 hours between seasonable；

Described hydroxy polymer mean molecule quantity M_w=50000～300000；

Described novel hydrates kinetic inhibitor is applied to hydration in oil gas water three phase system, profit or air water two-phase system The generation of thing；

When described inhibitor uses, first it is configured to aqueous solution, the concentration of described aqueous solution is 0.1wt%～5wt%.

2. according to claim 1 novel hydrates kinetic inhibitor it is characterised in that described solvent includes solubility alcohol Class or solubility ethers.

3. according to claim 1 novel hydrates kinetic inhibitor it is characterised in that monomer used by synthetic inhibitor with The volume ratio of solvent is 1：3～4：1.