A method for synthesizing crystalline granular acid ammonium fluoride salt from fluorine-containing spent concentrated sulfuric acid, products and applications

Abstract

The application discloses a method for synthesizing a granular acid ammonium fluoride salt from fluorine-containing waste concentrated sulfuric acid, a product and application thereof, and relates to the technical field of oil and gas field chemical industry. The fluorine-containing waste concentrated sulfuric acid, which is a by-product in the production of boron trifluoride, is added with a dehydrating agent for dehydration, then added with ammonium fluoride, and stirred and kept warm at 90-120 DEG C, and then added with iron sulfate, and stirred and reacted at 90-120 DEG C to obtain an acid ammonium salt. The acid ammonium salt not only realizes the resource utilization of the fluorine-containing waste concentrated sulfuric acid, but also can be used as an oil and water well plugging remover for the acidification and plugging removal of oil and water wells. The acid ammonium salt is convenient to store, transport and use, has good safety in the use process, has a slow corrosion speed of near-well formation, a long swept distance, and has a better acidification and plugging removal effect.

Description

Technical Field

[0001] This invention relates to the field of oil and gas field chemical technology, and in particular to a method, product, and application for synthesizing granular acidic ammonium fluoride salts from fluorine-containing waste concentrated sulfuric acid. Background Technology

[0002] The production of boron trifluoride generates a large amount of byproduct sulfuric acid (approximately 96%). This sulfuric acid is not only highly concentrated but also contains up to 16.8 g / L of fluorine, which cannot be directly neutralized and discharged. Furthermore, there are many obstacles to its direct resource utilization. The problem of waste acid buildup in the factory is very serious, and a solution is urgently needed.

[0003] In view of this, the present invention is proposed. Summary of the Invention

[0004] The purpose of this invention is to provide a method, product, and application for synthesizing granular acidic ammonium fluoride salts from fluorine-containing waste concentrated sulfuric acid, in order to solve the problems existing in the prior art.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] One of the technical solutions of this invention provides a method for synthesizing acidic ammonium salts from fluorine-containing waste concentrated sulfuric acid, comprising the following steps:

[0007] A dehydrating agent is added to fluorine-containing waste concentrated sulfuric acid for dehydration, then ammonium fluoride is added, and the mixture is kept at 90-120°C with stirring. Ferric sulfate is then added, and the mixture is stirred and reacted at 90-120°C to obtain the acidic ammonium salt.

[0008] As a further preferred embodiment of the present invention, the dehydrating agent is anhydrous sodium sulfate.

[0009] As a further preferred embodiment of the present invention, the mass-to-volume ratio of ammonium fluoride, ferric sulfate and fluorine-containing waste concentrated sulfuric acid is 400-500 kg: 25-30 kg: 200 L.

[0010] As a further preferred embodiment of the present invention, the fluorine-containing waste sulfuric acid is a byproduct of the production of boron trifluoride; the fluorine content in the fluorine-containing waste sulfuric acid is 1.8-100 g / L.

[0011] As a further preferred embodiment of the present invention, the heat preservation and stirring time is 15-20 min; the stirring reaction time is 5-10 min.

[0012] The second technical solution of the present invention is to provide an acidic ammonium salt prepared by the above preparation method.

[0013] The third technical solution of this invention is to provide the application of the above-mentioned acidic ammonium salt as an unblocking agent for oil and water wells.

[0014] The fourth technical solution of the present invention is to provide an oil and water well unblocking agent containing the above-mentioned acidic ammonium salt.

[0015] The acidic ammonium salt product prepared by this invention is crystalline, white, and extremely soluble in water, with a solubility of approximately 70 g / 100 g in water. The pH value of the saturated solution is 3-3.5.

[0016] The treatment of fluorine-containing waste concentrated sulfuric acid involves complex chemical reactions. This invention implements a series of measures to obtain a product with high hardness at room temperature and easy to crush and process:

[0017] First, add an appropriate amount of anhydrous sodium sulfate, a dehydrating agent, to the fluorine-containing waste concentrated sulfuric acid to prevent the sulfuric acid from boiling up violently.

[0018] Secondly, adding sufficient ammonium fluoride powder generates an acidic ammonium salt. However, the product obtained from this treatment lacks hardness and is too soft, making it unsuitable for pulverization. Furthermore, this step is an exothermic reaction and involves the release of some hydrogen fluoride, requiring protective measures.

[0019] Finally, before the acidic ammonium salt is cooled, an appropriate amount of ferric sulfate is added to partially generate ferric ammonium alum seed crystals, which increases the strength of the product after solidification and makes it easier to crush and grind.

[0020] In existing technologies, when formulating unblocking agents for oil and water wells, argillaceous acid (typically containing 10%-15% hydrochloric acid and 3%-8% hydrofluoric acid) is used to remove mud blockage and improve the permeability of mudstone and sandstone formations to facilitate water injection or oil production. Hydrochloric acid in argillaceous acid can dissolve carbonates and iron-aluminum compounds in the formation, while hydrofluoric acid can dissolve clay and silicates. The acidic ammonium salt prepared in this invention can replace the key component argillaceous acid in the unblocking agent. This acidic ammonium salt has moderate strength, a pH of approximately 3.0-3.5, and a slow dissolution rate of carbonates. It will not cause wellbore collapse due to excessive corrosion leading to formation erosion near the wellbore, nor will it cause new blockage problems due to the large-scale formation of calcium sulfate and calcium fluoride. Furthermore, the acidic ammonium salt of this invention has a longer reach, a more lasting acid-based unblocking effect, and significant benefits in increasing production and injection.

[0021] The present invention discloses the following technical effects:

[0022] This invention provides a method for synthesizing granular acidic ammonium fluoride salts using fluorine-containing waste concentrated sulfuric acid as raw material. This method realizes the resource utilization of the by-product fluorine-containing waste concentrated sulfuric acid, and the prepared acidic ammonium salts can be used as unblocking agents for oil and water wells in acid unblocking.

[0023] The acidic ammonium salt prepared by this invention is easy to store, transport and use, and has good safety during use. It has a slow near-wellbore formation corrosion rate, a long affected distance, and better acid unblocking effect. Detailed Implementation

[0024] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0025] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0026] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0027] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0028] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0029] In the following embodiments of the present invention, the fluorine-containing waste concentrated sulfuric acid came from Shandong Wanbang Chemical Co., Ltd., and its composition was as follows: 95% H2SO4, 4% H2O and 1% HF, with a fluorine content of 16.8 g / L.

[0030] Example 1

[0031] 200L of fluorine-containing waste concentrated sulfuric acid was added to a fluoroplastic stirred atmospheric pressure reactor (the reflux condenser was turned on beforehand, and the water cooling temperature was 25℃). Then, 400kg of powdered ammonium fluoride was slowly and evenly added while continuously stirring. The reactor feed port was closed promptly during the feeding intervals and after the feeding was complete. The reactor was kept at 110℃ and stirred for 15 minutes. During the reaction, a boiling explosion occurred. Due to the exothermic reaction, the temperature rose sharply, and the water in the reactor boiled rapidly. At the same time, a large amount of hydrofluoric acid was volatilized, posing a great operational risk. Finally, the product was discharged from the bottom of the reactor.

[0032] The pilot product in this batch solidified quickly, and the discharge exhibited sticking to the agitator. After cooling, the product had moderate hardness, similar to Class I soil, with a hardness coefficient of 0.3, which is not conducive to crushing and grinding.

[0033] Example 2

[0034] 200L of fluorine-containing waste concentrated sulfuric acid was added to a fluoroplastic stirred atmospheric pressure reactor (with the reflux condenser pre-activated and water-cooled at 25℃). 25kg of powdered anhydrous sodium sulfate was added at once and stirred for 5 minutes. Then, 400kg of powdered ammonium fluoride was slowly and evenly added while continuously stirring. The reactor's feed port was closed promptly after each addition and after all additions were completed. The reactor was kept at 110℃ and stirred for 15 minutes. During the reaction, there was virtually no boiling over; only a small amount of hydrofluoric acid evaporated. Finally, the product was discharged from the bottom of the reactor.

[0035] This batch of pilot-scale products also exhibited a sticking issue with the agitator. hardness It is slightly improved compared to Example 1, similar to Class II soil, with a firmness coefficient of 0.5. The product is still sticky and not easy to crush, process and grind.

[0036] Example 3

[0037] 200L of fluorine-containing waste concentrated sulfuric acid was added to a fluoroplastic stirred atmospheric pressure reactor (with the reflux condenser pre-activated and water-cooled at 25℃). 25kg of powdered anhydrous sodium sulfate was added at once and stirred for 5 minutes. Then, 400kg of powdered ammonium fluoride was slowly and uniformly added while continuously stirring. The reactor's feed port was closed promptly after each addition and after all additions were completed. The reactor was kept at 110℃ and stirred for 15 minutes. Next, 25kg of powdered ferric sulfate was added, and stirring continued at 110℃ for another 5 minutes. The viscosity of the reaction system decreased significantly. Finally, the product was discharged from the bottom of the reactor. The final product was virtually non-stick to the reactor and agitator, making discharge very convenient. A conveyor belt was used for uniform discharge, and bottom water cooling facilitated rapid solidification.

[0038] This batch of pilot-scale products exhibits rapid solidification, high strength, and similarity to Class II soil, with a solidification coefficient of 0.8. It is easily pulverized and ground into a fine white powder, and does not readily re-agglomerate. Furthermore, it possesses excellent water solubility (70g / 100g) and a pH of 3.2 for its saturated solution. The product obtained in this production run will be designated as the final product, code-named WB-F-01.

[0039] Example of effect verification:

[0040] The acidic ammonium salt product prepared according to this invention was prepared into a 25 wt.% aqueous solution (labeled as 25 wt.% WB-F-01 aqueous solution), and its effect on dissolving potassium feldspar and calcite was compared with that of terpinen acid (12 wt.% HCl + 8 wt.% HF). The results are shown in Table 1.

[0041] Table 1

[0042]

[0043] Currently, the main agent used for acidizing and unblocking oil and water wells is terrestrial acid. However, the formulation of terrestrial acid must be strictly based on the formation geology because hydrochloric acid specifically dissolves calcite but has no effect on feldspar, while hydrofluoric acid can only specifically dissolve feldspar, requiring adjustments to its dosage based on feldspar content, which poses difficulties for downhole operations. The acidic ammonium salt of this invention can effectively solve this problem. Furthermore, while the initial dissolution rate of acidic ammonium salt on potassium feldspar is slower, it gradually achieves a dissolution effect similar to that of terrestrial acid in the later stages. Moreover, the acidic effect has a longer reach, resulting in a more lasting acid-based unblocking effect and more significant production and injection benefits. In addition, the slower dissolution rate of the acidic ammonium salt of this invention on calcite is beneficial for unblocking oil and water wells.

[0044] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for synthesizing acidic ammonium salts from fluorine-containing waste concentrated sulfuric acid, characterized in that, Includes the following steps: A dehydrating agent is added to fluorine-containing waste concentrated sulfuric acid for dehydration, then ammonium fluoride is added, and the mixture is kept at 90-120°C with stirring. Ferric sulfate is then added, and the mixture is stirred and reacted at 90-120°C to obtain the acidic ammonium salt. The fluorine-containing waste concentrated sulfuric acid is a byproduct of boron trifluoride production; The fluorine content in the fluorine-containing waste concentrated sulfuric acid is 1.8-100 g / L.

2. The method according to claim 1, characterized in that, The dehydrating agent is anhydrous sodium sulfate.

3. The method according to claim 1, characterized in that, The mass-to-volume ratio of ammonium fluoride, ferric sulfate, and fluorine-containing waste concentrated sulfuric acid is 400-500 kg: 25-30 kg: 200 L.

4. The method according to claim 1, characterized in that, The heat preservation and stirring time is 15-20 minutes; the stirring reaction time is 5-10 minutes.

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