Scale inhibitor and preparation method thereof

Abstract

The invention belongs to the technical field of oil and gas field produced water treatment, and particularly relates to a scale inhibitor and a scale inhibitor preparation method. The scale inhibitor comprises amino trimethylphosphonic acid, hydroxyethylidene diphosphonic acid, ethylenediamine tetraacetic acid, modified sulfonate and potassium hydroxide. The scale inhibitor has a good scale inhibition effect, greatly prolongs the cleaning period of equipment, ensures the long-term stable operation of the equipment, and plays an important role in improving the operation efficiency and reducing the maintenance cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil and gas field produced water treatment, and specifically relates to a scale inhibitor and a preparation method thereof. Background Art

[0002] Produced water from heavy oil contains cations such as calcium, magnesium, strontium, and anions such as sulfate and carbonate. Compounds composed of these ions will crystallize and precipitate due to changes in concentration and temperature reaching supersaturation, thus forming scale.

[0003] During the treatment of produced water from heavy oil, after the cations and anions in the produced water from heavy oil crystallize and precipitate supersaturated, they will adhere to the inner wall of the treatment equipment to form scale, especially under high-temperature conditions, this situation is more severe. Of course, in production, due to various reasons such as operation reasons and inaccurate measuring instruments, salt crystallization and precipitation will also occur, adhering to the inner wall of the treatment equipment to form salt scale. The generation of salt scale will not only reduce the effective volume of the equipment, but also reduce the heat transfer coefficient of related equipment, deteriorate the production conditions, and in severe cases, will also reduce the equipment life or even damage the equipment, increasing energy consumption.

[0004] Currently, there are the following several conventional scale removal methods.

[0005] Alkali boiling - acid pickling method: First, prepare a cleaning solution with a concentration of 3% - 5% using soda ash, circulate it under heating, then circulate it with an acid cleaning solution, and finally rinse it with fresh water. This method can remove scale layers such as calcium sulfate, but the cost is high, and it is difficult to obtain the used acids and alkalis, with a relatively high cost.

[0006] Mechanical method: Use a "pipe cleaner" to remove the scale layer by scraping it with a mechanical knife under the accompaniment of water flow. However, this method has low cleaning efficiency and causes great damage to copper and titanium pipes, so it is not suitable for use.

[0007] Currently, the components of commonly used water treatment scale inhibitors all have some disadvantages, such as being easily decomposed under high-temperature conditions, insufficient stability, and poor effects in the case of complex scaling ions in water. Summary of the Invention

[0008] In view of the above technical problems, the present invention aims to provide a scale inhibitor, which has a good scale inhibition effect, greatly extends the equipment cleaning cycle, ensures the long-term stable operation of the equipment, and plays an important role in improving the operation efficiency and reducing the maintenance cost.

[0009] The present invention also provides a preparation method of a scale inhibitor.

[0010] According to the present invention, a scale inhibitor is provided, comprising: aminotrimethylphosphonic acid, hydroxyethylidene diphosphonic acid, ethylenediaminetetraacetic acid, modified sulfonate, and potassium hydroxide.

[0011] According to the present invention, in a preferred embodiment, by weight, 25 to 35 parts of aminotrimethylphosphonic acid, 5 to 15 parts of hydroxyethane diphosphonic acid, 1 to 5 parts of ethylenediaminetetraacetic acid, 1 to 10 parts of modified sulfonate, and 1 to 10 parts of potassium hydroxide.

[0012] According to the present invention, in a preferred embodiment, 29 parts of aminotrimethylphosphonic acid, 10 parts of hydroxyethane diphosphonic acid, 3 parts of ethylenediaminetetraacetic acid, 5 parts of modified sulfonate, and 4 parts of potassium hydroxide.

[0013] According to the present invention, there is also provided a preparation method of the scale inhibitor provided by the present invention, including:

[0014] Step 1, adding aminotrimethylphosphonic acid, hydroxyethane diphosphonic acid, ethylenediaminetetraacetic acid and water into a reaction kettle, and stirring evenly;

[0015] Step 2, adding potassium hydroxide into the reaction kettle;

[0016] Step 3, adding modified sulfonate and water into the reaction kettle, and stirring evenly.

[0017] According to the present invention, in a preferred embodiment, the water is soft water.

[0018] According to the present invention, in a preferred embodiment,

[0019] In Step 1, adding 29 parts by weight of aminotrimethylphosphonic acid, 10 parts by weight of hydroxyethane diphosphonic acid, 3 parts by weight of ethylenediaminetetraacetic acid and 40 parts by weight of soft water into the reaction kettle, and stirring evenly;

[0020] In Step 2, adding 4 parts by weight of potassium hydroxide into the reaction kettle;

[0021] In Step 3, adding 5 parts by weight of modified sulfonate and 9 parts by weight of soft water into the reaction kettle, and stirring evenly.

[0022] According to the present invention, in a preferred embodiment,

[0023] In Step 1, after mixing hydroxyethane diphosphonic acid, ethylenediaminetetraacetic acid and soft water, stirring for at least 30 minutes;

[0024] In Step 2, after adding potassium hydroxide into the reaction kettle, waiting for the raw materials in the reaction kettle to react for at least 1 hour, and then proceeding to Step 3;

[0025] In Step 3, after adding modified sulfonate and soft water into the reaction kettle, stirring for at least 30 minutes.

[0026] According to the present invention, a scale inhibitor is also provided, which comprises: hydroxyethylidene diphosphonic acid, aminotrimethylphosphonic acid, PBTCA and polyaspartic acid.

[0027] According to the present invention, in a preferred embodiment, by weight, there are 40 - 50 parts of hydroxyethylidene diphosphonic acid, 10 - 20 parts of aminotrimethylphosphonic acid, 5 - 10 parts of PBTCA, and 5 - 10 parts of polyaspartic acid.

[0028] According to the present invention, in a preferred embodiment, the working temperature of the scale inhibitor is 60 - 105 °C.

[0029] Compared with the prior art, the advantages of the present application are as follows.

[0030] In view of the characteristics of complex scale - forming ions and high operating temperature in produced water from heavy oil production, the present invention has successfully achieved scale inhibition during the operation of the produced water treatment equipment for heavy oil, thereby reducing the operating cost and extending the maintenance cycle of the produced water treatment equipment for heavy oil.

[0031] The components of the scale inhibitor of the present invention cooperate with each other, mainly playing the roles of chelating solubilization and dispersion, preventing the scale - forming particles from forming a regular lattice point structure, promoting lattice distortion of the scale - forming particles, and being easily washed away by the water flow. Detailed implementation manners

[0032] The following introduces the present invention.

[0033] According to the present invention, a scale inhibitor is provided, which comprises: aminotrimethylphosphonic acid, hydroxyethylidene diphosphonic acid, ethylenediaminetetraacetic acid, modified sulfonate and potassium hydroxide.

[0034] In a preferred embodiment, by weight, the scale inhibitor comprises:

[0035] 25 - 35 parts of aminotrimethylphosphonic acid;

[0036] 5 - 15 parts of hydroxyethylidene diphosphonic acid;

[0037] 1 - 5 parts of ethylenediaminetetraacetic acid;

[0038] 1 - 10 parts of modified sulfonate;

[0039] 1 - 10 parts of potassium hydroxide.

[0040] The components in the above - mentioned scale inhibitor cooperate with each other, mainly playing the roles of chelating solubilization and dispersion, preventing the scale - forming particles from forming a regular lattice point structure, promoting lattice distortion of the scale - forming particles, and being easily washed away by the water flow.

[0041] In a better embodiment, by weight, the components of the scale inhibitor are:

[0042] 29 parts of aminotrimethylphosphonic acid;

[0043] 10 parts of hydroxyethylidene diphosphonic acid;

[0044] 3 parts of ethylenediaminetetraacetic acid;

[0045] 5 parts of modified sulfonate;

[0046] 4 parts of potassium hydroxide.

[0047] The present invention also provides a preparation method of a scale inhibitor, comprising:

[0048] Step 1, adding aminotrimethylphosphonic acid, hydroxyethylidene diphosphonic acid, ethylenediaminetetraacetic acid and water into a reaction kettle, and stirring evenly;

[0049] Step 2, adding potassium hydroxide into the reaction kettle;

[0050] Step 3, adding modified sulfonate and water into the reaction kettle, and stirring evenly.

[0051] In a preferred embodiment, the water added in Step 1 and Step 3 of the preparation method of the scale inhibitor is soft water.

[0052] Example 1:

[0053] This example provides a scale inhibitor. According to parts by weight, the proportion of each component is:

[0054] 25 parts of aminotrimethylphosphonic acid;

[0055] 5 parts of hydroxyethylidene diphosphonic acid;

[0056] 1 part of ethylenediaminetetraacetic acid;

[0057] 1 part of modified sulfonate;

[0058] 1 part of potassium hydroxide.

[0059] The preparation method of the above scale inhibitor includes: first, adding 25 parts by weight of aminotrimethylphosphonic acid, 5 parts by weight of hydroxyethylidene diphosphonic acid, 1 part by weight of ethylenediaminetetraacetic acid and 35 - 45 parts by weight of soft water into a reaction kettle, stirring evenly for at least 30 minutes; then slowly adding 1 part by weight of potassium hydroxide from the top feeding port of the reaction kettle and waiting for the raw materials inside the reaction kettle to react for at least 1 hour; finally, adding 1 part by weight of modified sulfonate and 5 - 15 parts by weight of soft water into the reaction kettle, stirring for at least 30 minutes, and after stirring evenly, measuring the materials and packaging them in plastic buckets.

[0060] Example 2:

[0061] This example provides a scale inhibitor. According to parts by weight, the proportion of each component is:

[0062] 35 parts of aminotrimethylphosphonic acid;

[0063] 15 parts of hydroxyethane-1,1-diphosphonic acid;

[0064] 5 parts of ethylenediaminetetraacetic acid;

[0065] 10 parts of modified sulfonate;

[0066] 10 parts of potassium hydroxide.

[0067] The preparation method of the above scale inhibitor includes: firstly, adding 35 parts by weight of aminotrimethylphosphonic acid, 15 parts by weight of hydroxyethane-1,1-diphosphonic acid, 5 parts by weight of ethylenediaminetetraacetic acid and 35 - 45 parts by weight of soft water into the reaction kettle, stirring evenly for at least 30 minutes; then slowly adding 10 parts by weight of potassium hydroxide from the top feeding port of the reaction kettle and waiting for at least 1 hour for the internal raw materials in the reaction kettle to react; finally, adding 10 parts by weight of modified sulfonate and 5 - 15 parts by weight of soft water into the reaction kettle, stirring for at least 30 minutes, after stirring evenly, measuring the materials and packaging them with plastic barrels.

[0068] Example 3:

[0069] This example provides a scale inhibitor, and the proportion of each component by weight is:

[0070] 29 parts of aminotrimethylphosphonic acid;

[0071] 10 parts of hydroxyethane-1,1-diphosphonic acid;

[0072] 3 parts of ethylenediaminetetraacetic acid;

[0073] 5 parts of modified sulfonate;

[0074] 4 parts of potassium hydroxide.

[0075] The preparation method of the above scale inhibitor includes: firstly, adding 29 parts by weight of aminotrimethylphosphonic acid, 10 parts by weight of hydroxyethane-1,1-diphosphonic acid, 3 parts by weight of ethylenediaminetetraacetic acid and 40 parts by weight of soft water into the reaction kettle, stirring evenly for at least 30 minutes; then slowly adding 4 parts by weight of potassium hydroxide from the top feeding port of the reaction kettle and waiting for at least 1 hour for the internal raw materials in the reaction kettle to react; finally, adding 5 parts by weight of modified sulfonate and 9 parts by weight of soft water into the reaction kettle, stirring for at least 30 minutes, after stirring evenly, measuring the materials and packaging them with plastic barrels.

[0076] Example 4:

[0077] In addition, in an embodiment of the present invention, another scale inhibitor is also provided, including: hydroxyethane-1,1-diphosphonic acid, aminotrimethylphosphonic acid, PBTCA and polyaspartic acid.

[0078] In a specific embodiment provided by the present invention, the components of the scale inhibitor are proportioned by weight, including:

[0079] 40 - 50 parts of hydroxyethylidene diphosphonic acid;

[0080] 10 - 20 parts of aminotrimethylphosphonic acid;

[0081] 5 - 10 parts of PBTCA;

[0082] 5 - 10 parts of polyaspartic acid.

[0083] According to the water quality analysis results of heavy oil produced water, it is judged that the scaling ions are cations such as calcium, magnesium, strontium, etc. and anions such as sulfate, carbonate, etc. The scale inhibitor provided by the present invention can reduce the scaling rate of heavy oil produced water in a working environment of 60 - 105 °C.

[0084] In an embodiment of the present invention, a falling film evaporation process for heavy oil produced water is further provided. This process adds the scale inhibitor provided by the present invention to the heavy oil produced water to prevent the treatment equipment of heavy oil produced water from scaling.

[0085] In a preferred embodiment, the working temperature range of the heavy oil produced water in the falling film evaporation process is 60 - 105 °C.

[0086] In a specific embodiment, the falling film evaporation process of heavy oil produced water includes the following steps: mixing the heavy oil produced water with the scale inhibitor; passing through a falling film evaporator.

[0087] In this embodiment, the heavy oil produced water and the scale inhibitor are respectively added to the falling film evaporator through different channels, and the addition amounts of the heavy oil produced water and the scale inhibitor can be respectively adjusted. By adjusting the addition amounts of the heavy oil produced water and the scale inhibitor, the concentration of the scale inhibitor in the heavy oil produced water is adjusted.

[0088] On the falling film evaporator, there is a water injection port for adding heavy oil produced water and a plurality of injection ports for adding the scale inhibitor. The plurality of injection ports are evenly distributed along the circumferential direction of the falling film evaporator, and the amount of the scale inhibitor is adjusted through the injection ports.

[0089] In a preferred embodiment, a flow meter for measuring the flow rate of the heavy oil produced water is provided on the falling film evaporator.

[0090] Furthermore, the flow meter is arranged at the water injection port of the falling film evaporator to reduce the influence of the internal fluid of the falling film evaporator on the accuracy of flow rate detection.

[0091] In a preferred embodiment, the flowmeter is an ultrasonic flowmeter. Using an ultrasonic flowmeter can detect the flow more accurately. On the one hand, it can adjust the amount of viscous oil produced water according to the processing capacity of the falling film evaporation processor. On the other hand, it can adjust the dosage of the scale inhibitor according to the amount of viscous oil produced water.

[0092] In a preferred embodiment, each liter of viscous oil produced water corresponds to 6-9 mg of scale inhibitor.

[0093] The scale inhibitors in the prior art can only scale a single substance. For example, if the scale inhibition rate for CaCO3 can reach 80%, it is very difficult for the scale inhibition rate of SrSO4 to reach 60%; if the scale inhibition rate for SrSO4 can reach 80%, the scale inhibition rate of CaCO3 is very difficult to exceed 50%.

[0094] It has been experimentally proven that according to the technological process of the present invention, at a temperature of 60-105 °C, the scale inhibition rate is above 85%. Specifically, in the actual operation process, each liter of viscous oil produced water is correspondingly added with 4-5 mg of hydroxyethylidene diphosphonic acid, 1-2 mg of aminotrimethyl phosphonic acid, 0.5-1 mg of PBTCA, and 0.5-1 mg of polyaspartic acid. After using the scale inhibitor of the present invention, the scale inhibition rate of CaCO3 is greater than 89.5%, and the scale inhibition rate of SrSO4 is greater than 87.8%.

[0095] Example Five:

[0096] In this embodiment, the components of the scale inhibitor are proportioned by weight, including:

[0097] 40 parts of hydroxyethylidene diphosphonic acid;

[0098] 10 parts of aminotrimethyl phosphonic acid;

[0099] 5 parts of PBTCA;

[0100] 5 parts of polyaspartic acid.

[0101] The remaining technical features in this embodiment are the same as those in Example Four.

[0102] Example Six:

[0103] In this embodiment, the components of the scale inhibitor are proportioned by weight, including:

[0104] 50 parts of hydroxyethylidene diphosphonic acid;

[0105] 20 parts of aminotrimethyl phosphonic acid;

[0106] 10 parts of PBTCA;

[0107] 10 parts of polyaspartic acid.

[0108] The remaining technical features in this embodiment are the same as those in Embodiment IV.

[0109] Embodiment VII:

[0110] In this embodiment, the components of the scale inhibitor are proportioned by weight, including:

[0111] 45 parts of hydroxyethylidene diphosphonic acid;

[0112] 15 parts of aminotrimethyl phosphonic acid;

[0113] 7 parts of PBTCA;

[0114] 8 parts of polyaspartic acid.

[0115] The remaining technical features in this embodiment are the same as those in Embodiment IV.

[0116] In the description of the present invention, it should be understood that the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality" means two or more unless otherwise specifically defined.

[0117] In the present invention, unless otherwise clearly defined and limited, the terms "installed", "connected", "connected", "fixed", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0118] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0119] Finally, it should be noted that the above are only the preferred embodiments of the present invention and do not constitute any limitation to the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments or perform equivalent replacements for some of the technical features. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A scale inhibitor, characterized in that, Comprising: Aminotrimethylphosphonic acid, hydroxyethylidene diphosphonic acid, ethylenediaminetetraacetic acid, modified sulfonate, and potassium hydroxide.

2. The scale inhibitor according to claim 1, wherein By weight parts, 25 - 35 parts of aminotrimethylphosphonic acid, 5 - 15 parts of hydroxyethylidene diphosphonic acid, 1 - 5 parts of ethylenediaminetetraacetic acid, 1 - 10 parts of modified sulfonate, and 1 - 10 parts of potassium hydroxide.

3. The scale inhibitor according to claim 2, wherein, By weight parts, 29 parts of aminotrimethylphosphonic acid, 10 parts of hydroxyethylidene diphosphonic acid, 3 parts of ethylenediaminetetraacetic acid, 5 parts of modified sulfonate, and 4 parts of potassium hydroxide.

4. A method for preparing a scale inhibitor according to any one of claims 1 to 3, characterized in that, Comprising: Step 1: Add aminotrimethylphosphonic acid, hydroxyethylidene diphosphonic acid, ethylenediaminetetraacetic acid, and water into the reaction kettle, and stir evenly. Step 2: Add potassium hydroxide into the reaction kettle. Step 3: Add modified sulfonate and water into the reaction kettle, and stir evenly.

5. The preparation method according to claim 4, characterized in that, The water is soft water.

6. The preparation method according to claim 5, wherein In step 1, add 29 parts by weight of aminotrimethylphosphonic acid, 10 parts by weight of hydroxyethylidene diphosphonic acid, 3 parts by weight of ethylenediaminetetraacetic acid, and 40 parts by weight of soft water into the reaction kettle, and stir evenly. In step 2, add 4 parts by weight of potassium hydroxide into the reaction kettle. In step 3, add 5 parts by weight of modified sulfonate and 9 parts by weight of soft water into the reaction kettle, and stir evenly.

7. The preparation method according to claim 6, wherein In step 1, after mixing hydroxyethylidene diphosphonic acid, ethylenediaminetetraacetic acid, and soft water, stir for at least 30 minutes. In step 2, after adding potassium hydroxide into the reaction kettle, wait for the raw materials in the reaction kettle to react for at least 1 hour, and then proceed to step 3. In step 3, after adding modified sulfonate and soft water into the reaction kettle, stir for at least 30 minutes.

8. A scale inhibitor, characterized in that, Comprising: Hydroxyethylidene diphosphonic acid, aminotrimethylphosphonic acid, PBTCA, and polyaspartic acid.

9. The scale inhibitor according to claim 8, characterized in that, By weight parts, 40 - 50 parts of hydroxyethylidene diphosphonic acid, 10 - 20 parts of aminotrimethylphosphonic acid, 5 - 10 parts of PBTCA, and 5 - 10 parts of polyaspartic acid.

10. The scale inhibitor according to claim 9, wherein The working temperature of the scale inhibitor is 60 - 105 °C.