High-temperature-resistant lignite resin and preparation method thereof

Abstract

The invention discloses a high-temperature-resistant lignite resin and a preparation method thereof, and belongs to the field of drilling fluids, and the preparation method comprises the following steps: obtaining and preparing an extracting solution containing humic acid from lignite; adding hydrochloric acid into the extracting solution, separating, filtering and precipitating, dissolving the precipitating in a sodium hydroxide solution to obtain a humic acid solution, adding formaldehyde and sodium pyrosulfite into the humic acid solution, preheating to 80 DEG C, adding the extracting solution, heating to 110-130 DEG C, continuously stirring, reacting for 1-3 hours, and cooling to 60 DEG C or below to obtain a reaction product; transferring a reaction product to a neutralizing tank, dropwise adding a NaOH solution, adjusting the pH value to 10-11, and controlling the temperature below 55 DEG C; the mass ratio of the dry basis mass of sulfonated humic acid to ECH is 1: (0.05-0.15), the temperature is kept at 45-55 DEG C, the stirring speed is 400-600 rpm, and the reaction is performed for 2-4 hours; meanwhile, a NaOH solution is continuously added, and the pH is kept at 10-11. Adjusting the pH value of the reaction liquid to 7-8 by using dilute HCl, and terminating the reaction; and obtaining a resin product.

Description

Technical Field

[0001] The present invention relates to lignite resin, and more specifically to a high-temperature resistant lignite resin and a preparation method thereof. Background Art

[0002] Sulfonated lignite is a derivative of lignite humic acid, which is synthesized from lignite under the conditions of a sulfonating agent, appropriate temperature, etc. Its appearance is brownish-black powder, and it is a viscosity reducer and filtration loss control agent for drilling fluids.

[0003] The patent document with the application number 202311561417.0 discloses a preparation method of lignite resin and the application of lignite resin. The preparation method includes: crushing and screening lignite and then introducing it into a leaching device, heating and stirring during the dissolution and precipitation process, introducing the leaching solution of the leaching into a sedimentation tank and a centrifuge for separation and then performing evaporation treatment, and performing precipitation, adsorption, and filtration treatment on the pure solution after evaporation treatment and then introducing it into a drying device for drying treatment. The present invention uses coal tar as a leaching solvent, heats and stirs during the leaching process to ensure the dissolution and precipitation effect of lignite resin organic matter, separates the solid and liquid of the leaching solution through a sedimentation tank and a centrifuge, dehydrates using an evaporator, performs purification treatment by combining precipitation, adsorption, and filtration, then heats and dries, and then introduces it into a cyclone separator for further drying and impurity removal under the action of an air heater.

[0004] However, the current sulfonated lignite resin has insufficient high-temperature resistance performance and is restricted in use in drilling fluids. Summary of the Invention

[0005] The purpose of the present invention is to disclose a preparation method of a high-temperature resistant lignite resin for the problems in the prior art, and the steps are as follows:

[0006] Obtain an extract containing humic acid from lignite;

[0007] Add hydrochloric acid to the extract, separate and filter the precipitate, dissolve the precipitate in sodium hydroxide solution to obtain a humic acid solution

[0008] Add formaldehyde and sodium metabisulfite to the humic acid solution, preheat to 80°C, add the extract, raise the temperature to 110°C - 130°C and continuously stir. After the reaction for 1 - 3 hours, cool to below 60°C to obtain a reaction product

[0009] Transfer the reaction product to a neutralization tank, dropwise add NaOH solution to adjust the pH to 10 - 11, and at the same time control the temperature below 55°C;

[0010] Add epichlorohydrin (sulfonated humic acid dry basis mass: ECH = 1:0.05 - 0.15 (mass ratio)), keep the temperature at 45 - 55 °C, the stirring speed is 400 - 600 rpm, and react for 2 - 4 hours; at the same time, continuously add NaOH solution to keep the pH at 10 - 11.

[0011] Adjust the reaction solution to pH 7 - 8 with dilute HCl to terminate the reaction;

[0012] Separate the product with a vacuum filtration device, wash it with deionized water until the conductivity of the filtrate < 100 μS / cm to obtain the resin product.

[0013] In the preferred scheme, the reaction temperature in step three is 120 °C - 130 °C.

[0014] In the preferred scheme, the concentration of the NaOH solution is 20%.

[0015] In the preferred scheme, the temperature in step four is controlled at 50 °C - 55 °C.

[0016] In the preferred scheme, the method for obtaining an extract containing humic acid from lignite is as follows: Select natural lignite with a humic acid content > 50%, crush it to 80 - 100 mesh; dry the lignite at 60 - 80 °C until the moisture content < 5%, add an alkali solution, where the solid - liquid ratio is 1:5 - 1:20, stir for 1 - 3 hours, and filter to obtain the extract. In the preferred scheme, the solid - liquid ratio is 1:5.

[0017] In the preferred scheme, it further includes reacting the resin product with 3 - mercaptopropionic acid to obtain the final product.

[0018] This application also discloses a lignite resin prepared according to the described method.

[0019] The lignite resin disclosed in this application has excellent high - temperature resistance performance and can improve the use effect in drilling fluids. Detailed Description of the Invention

[0020] In order to more clearly understand the above - mentioned objects, features, and advantages of the present invention application, the following further describes the present invention application in conjunction with embodiments. It should be noted that, without conflict, the embodiments of the present application and the features in the embodiments can be combined with each other.

[0021] In the following description, many specific details are set forth to fully understand the present invention application. However, the present invention application can also be implemented in other ways different from those described herein. Therefore, the present invention application is not limited by the specific embodiments disclosed in the following specification.

[0022] Comparative Example 1: Select natural lignite with humic acid content > 50%, and crush it to 100 mesh; dry the lignite at 80 °C until the moisture content < 5%, add an alkali solution with a solid-liquid ratio of 1:20, stir for 3 hours, and filter to obtain an extract; add appropriate hydrochloric acid to the extract, separate and filter the precipitate, dissolve the precipitate in an appropriate amount of sodium hydroxide solution to obtain a humic acid solution; slowly add formaldehyde to the humic acid solution with a mass ratio of dry humic acid basis: formaldehyde = 1:0.4, control the temperature at about 65 °C for reaction, and stir for 1.5 hours. Then add sodium metabisulfite powder (dry humic acid basis mass: sodium metabisulfite = 1:0.6), adjust the pH to 6 with dilute HCl, raise the temperature to 85 °C and react for 3 hours, cool to below 60 °C to obtain a reaction product; transfer the reaction product to a neutralization tank, dropwise add NaOH solution to adjust the pH to 10 to terminate the reaction; separate the product, wash it with deionized water until the conductivity of the filtrate < 100 μS / cm to obtain lignite resin.

[0023] Example 1: Select natural lignite with humic acid content > 50%, and crush it to 100 mesh; dry the lignite at 80 °C until the moisture content < 5%, add an alkali solution with a solid-liquid ratio of 1:20, stir for 3 hours, and filter to obtain an extract; add appropriate hydrochloric acid to the extract, separate and filter the precipitate, dissolve the precipitate in an appropriate amount of sodium hydroxide solution to obtain a humic acid solution; slowly add formaldehyde to the humic acid solution with a mass ratio of dry humic acid basis: formaldehyde = 1:0.4, control the temperature at about 65 °C for reaction, and stir for 1.5 hours. Then add sodium metabisulfite powder (dry humic acid basis mass: sodium metabisulfite = 1:0.6), adjust the pH to 6 with dilute HCl, raise the temperature to 85 °C and react for 3 hours, cool to below 60 °C to obtain a reaction product; transfer the reaction product to a neutralization tank, dropwise add NaOH solution, and when adjusting the pH to 10, heat the temperature to about 53 °C; add epichlorohydrin (sulfonated dry humic acid basis mass: epichlorohydrin = 1:0.1 (mass ratio)), keep the temperature at about 53 °C, stir at a speed of 500 rpm, and react for 3 hours; at the same time, continuously add NaOH solution to keep the pH between 10 and 11. Adjust the reaction solution to pH 7 with dilute HCl to terminate the reaction; separate the product with a vacuum filtration device, wash it with deionized water until the conductivity of the filtrate < 100 μS / cm to obtain lignite resin.

[0024] Example 2: Obtain the resin product of Comparative Example 1. Dissolve 50 g of the resin product powder in 200 mL of DMF, stir at 60 °C for 2 h to ensure complete dissolution, add 5% NaOH solution to adjust the pH to 8, test the active sites of the resin product, and the result is 2.7 mmol / g. Add 3-mercaptopropionic acid (ensure that the molar ratio of active sites of lignite resin to 3-mercaptopropionic acid is 1:1.2), add 0.5 mL of concentrated sulfuric acid, react at 80 °C under nitrogen protection for 7 h, cool to room temperature, adjust the pH to neutral with dilute hydrochloric acid, pour the mixture into excessive ethanol for precipitation, centrifuge and separate, wash with ethanol three times, and dry under vacuum to obtain the modified product, and measure the relevant properties.

[0025] Example 3: Obtain the resin product of Example 1. Dissolve 50 g of the resin product powder in 200 mL of DMF, stir at 60 °C for 2 h to ensure complete dissolution, add 5% NaOH solution to adjust the pH to 8, test the active sites of the resin product, and the result is 3.2 mmol / g. Add 3-mercaptopropionic acid (ensure that the molar ratio of active sites of lignite resin to 3-mercaptopropionic acid is 1:1.2), add 0.5 mL of concentrated sulfuric acid, react at 80 °C under nitrogen protection for 7 h, cool to room temperature, adjust the pH to neutral with dilute hydrochloric acid, pour the mixture into excessive ethanol for precipitation, centrifuge and separate, wash with ethanol three times, and dry under vacuum to obtain the modified product, and measure the relevant properties.

[0026] Filtrate loss measurement:

[0027] Take clear water, start the high-speed stirrer, slowly add bentonite (the final concentration of bentonite is 9 g / 100 ml), stir for 30 minutes, and let it stand for hydration for 24 hours to obtain the base slurry. Slowly add the prepared different sulfonated lignite resin dry powders in proportion (10 kg / m 3 ) to the base slurry, continuously stir at high speed (≥6000 rpm) for 1 h to ensure full dispersion of the resin. Take 350 ml and measure the high-temperature and high-pressure filtrate loss under a high-temperature environment (200 °C, pressure 3.45 MPa). The results are shown in Table 1:

[0028] High-temperature aging test:

[0029] Take the drilling fluid sample, record the initial plastic viscosity, put the sample into the aging tank, seal it and place it in a high-temperature roller furnace, set the temperature to 200 °C, and heat it by rolling for 24 h; take out the aging tank, cool it to room temperature, and measure the plastic viscosity after aging.

[0030] Table 1: Performance measurement results

[0031]

[0032] Analysis of performance measurement results: After two cross-linking reactions with epichlorohydrin in Example 1, its high-temperature filtration loss resistance performance was significantly improved; and its high-temperature aging resistance performance was also significantly enhanced, and its effect was significantly better than that of the single cross-linking reaction. Example 2 was a further reaction of the product of Comparative Example 1 and 3-mercaptopropionic acid, and its high-temperature filtration loss resistance performance did not change significantly. Example 3 was the product of Example 1, and its high-temperature filtration loss resistance performance and aging performance had significant changes, which might be due to the reaction of 3-mercaptopropionic acid with specific functional groups of the cross-linking agent, increasing the cross-linking.

Claims

1. A preparation method of a high-temperature resistant lignite resin, characterized in that, The steps are as follows:

1. Obtain an extract containing humic acid from lignite; 2. Add hydrochloric acid to the extract, separate and filter the precipitate, dissolve the precipitate in sodium hydroxide solution to obtain a humic acid solution; 3. Add formaldehyde and sodium metabisulfite to the humic acid solution, after reacting for 1 - 3 hours and then cooling to below 60 °C, obtain a reaction product; 4. Transfer the reaction product to a neutralization tank, dropwise add NaOH solution to adjust the pH to 10 - 11, and at the same time control the temperature below 55 °C; 5. Add epichlorohydrin, keep the temperature at 45 - 55 °C, the stirring speed is 400 - 600 rpm, and react for 2 - 4 hours; at the same time, continuously add NaOH solution to keep the pH at 10 - 11; 6. Adjust the reaction solution to pH 7 - 8 with dilute HCl to terminate the reaction; 7. Separate the product with a vacuum filtration device, wash it with deionized water until the conductivity of the filtrate < 100 μS / cm to obtain a resin product.

2. The preparation method of the high-temperature resistant lignite resin according to claim 1, wherein, The solid - liquid ratio in step 1 is 1:

5.

3. The preparation method of the high-temperature resistant lignite resin according to claim 2, characterized in that, The reaction temperature in step 3 is 120 °C - 130 °C.

4. The preparation method of the high-temperature resistant lignite resin according to claim 3, characterized in that, The concentration of the said NaOH solution is 20%.

5. The preparation method of lignite resin according to claim 4, characterized in that, Control the temperature at 50 °C - 55 °C in step 4.

6. The preparation method of the high-temperature resistant lignite resin according to claim 1, wherein, The method for obtaining an extract containing humic acid from lignite is as follows: Select natural lignite with a humic acid content > 50%, crush it to 80 - 100 mesh; dry the lignite at 60 - 80 °C until the moisture content < 5%, add an alkali solution, where the solid - liquid ratio is 1:5 - 1:20, stir for 1 - 3 hours, and filter to obtain the extract.

7. The preparation method of the high-temperature resistant lignite resin according to claim 1, characterized in that It also includes reacting the resin product with 3 - mercaptopropionic acid to obtain a final product.

8. An anti-high-temperature lignite resin, characterized in that, Prepared according to any one of claims 1 - 7.

Images