Circulating water scale inhibitor and application thereof

Abstract

The invention belongs to the technical field of circulating water treatment, and particularly relates to a circulating water scale inhibitor. The invention discloses a water-soluble detergent, which is prepared from the following ingredients in percentage by weight: 3 to 7 parts of tannin, 3 to 7 parts of sodium gluconate, 5 to 15 parts of polyaspartic acid, 5 to 15 parts of sodium polyacrylate, 5 to 15 parts of itaconic acid / 2-acrylamide-2-methylpropanesulfonic acid (IA / AMPS) copolymers, 10 to 20 parts of zinc sulfate, 10 to 20 parts of sodium orthosilicate, 15 to 25 parts of sodium citrate and 5 to 15 parts of sodium dodecyl benzene sulfonate. According to the invention, a water treatment agent with good biodegradability is selected and optimized and compounded, so that the phosphorus-free, environment-friendly and high-performance circulating water corrosion and scale inhibitor is successfully prepared; the cleaning agent does not contain nitrite, phosphate and other substances causing water source pollution, and is green, environment-friendly, convenient to use and low in cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of circulating water treatment, and particularly relates to a circulating water scale inhibitor and its preparation and application. Background Art

[0002] Cooling water circulates in an open recirculating cooling system. Due to factors such as rising water temperature, changing water flow velocity, water evaporation, concentration of various inorganic ions and organic substances, exposure of the cooling tower and cooling water to outdoor sunlight, wind, rain, and the entry of dust and debris, as well as the comprehensive effects of equipment structure and materials, if the water quality is not treated or the water treatment is improper, the system will have three major problems: serious sediment attachment (scaling), equipment corrosion, and massive growth of microorganisms, as well as problems such as the blockage of pipelines by slime and dirt formed therefrom. These will seriously threaten and damage the operation of production devices, bringing huge economic losses to enterprises.

[0003] Sediments are collectively referred to as dirt, and are divided into water scale (hard scale) and sludge (soft scale). Among them, sludge includes silt, slime, and corrosion products. Water scale, also known as hard scale or inorganic scale, is the scale formed when the poorly soluble or slightly soluble salts brought into the makeup water change under the conditions of circulating water. Common ones include calcium carbonate, calcium phosphate, calcium sulfate, magnesium hydroxide, magnesium silicate, etc. Sludge, also known as soft scale, often contains sludge, dust, sand, corrosion products, natural organic matter, microbial colonies and secretions, iron phosphate, aluminum oxide, aluminum phosphate, and general debris.

[0004] The deposition of hard scale and soft scale on the heat exchanger will affect heat transfer, resulting in a decrease in the efficiency of the heat exchanger. In severe cases, it will block the heat exchanger, increase the system resistance, reduce the efficiency of the water pump and cooling tower, and increase production energy consumption. In addition, soft scale will promote under-scale corrosion, and this local corrosion is more harmful than general corrosion and can cause the corrosion perforation of the water cooler. In particular, the under-scale corrosion caused by microbial slime can cause the leakage of the water cooler in a short time and even lead to abnormal production stoppage.

[0005] In the water treatment method of the circulating cooling water system for the scaling problem, the main treatment methods are to remove scaling ions from the cooling water, add acid or charge CO2 to lower the pH, stabilize bicarbonate, add scale inhibitors, reduce the turbidity of makeup water, and increase side-stream filtration facilities, etc. According to the characteristics of the circulating cooling water system and the water quality properties, using reasonable corrosion and scale inhibitors and biocides can reduce the hazards caused by the corrosion, scaling, and microbial growth of metal materials in the system, extend the service life of the system, improve the utilization rate of equipment and water, and achieve the purpose of water conservation and energy saving. At present, the formulations of commonly used scale and corrosion inhibitors are prone to cause eutrophication of water bodies, resulting in environmental pollution, and are inconvenient to use, with poor scale inhibition effect and high cost. Low-phosphorus, phosphorus-free, and nitrite-free scale inhibitors have become the main research directions. Therefore, it is necessary to develop a circulating water scale inhibitor to solve these problems, reduce environmental pollution, and lay a good foundation for water conservation and emission reduction. Summary of the Invention

[0006] In order to achieve the above object, the technical solution adopted by the present invention is to provide a circulating water scale inhibitor and its preparation and application.

[0007] A circulating water scale inhibitor contains the following components in weight percentage: 3-7 parts of tannin, 3-7 parts of sodium gluconate, 5-15 parts of polyaspartic acid, 5-15 parts of sodium polyacrylate, 5-15 parts of itaconic acid / 2-acrylamide-2-methylpropanesulfonic acid (IA / AMPS) copolymer, 10-20 parts of zinc sulfate, 10-20 parts of sodium orthosilicate, 15-25 parts of sodium citrate, and 5-15 parts of sodium dodecylbenzenesulfonate.

[0008] Preferably, the circulating water scale inhibitor contains the following components in weight percentage: 4-6 parts of tannin, 4-6 parts of sodium gluconate, 8-12 parts of polyaspartic acid, 8-12 parts of sodium polyacrylate, 8-12 parts of itaconic acid / 2-acrylamide-2-methylpropanesulfonic acid (IA / AMPS) copolymer, 13-17 parts of zinc sulfate, 13-17 parts of sodium orthosilicate, 18-22 parts of sodium citrate, and 8-12 parts of sodium dodecylbenzenesulfonate.

[0009] Preferably, the circulating water scale inhibitor contains the following components in weight percentage: 5 parts of tannin, 5 parts of sodium gluconate, 10 parts of polyaspartic acid, 10 parts of sodium polyacrylate, 10 parts of itaconic acid / 2-acrylamide-2-methylpropanesulfonic acid (IA / AMPS) copolymer, 15 parts of zinc sulfate, 15 parts of sodium orthosilicate, 20 parts of sodium citrate, and 10 parts of sodium dodecylbenzenesulfonate.

[0010] The circulating water scale inhibitor of the present invention is used for water treatment, for corrosion inhibition and scale inhibition.

[0011] Compared with the prior art, the beneficial effects of the present invention are: The present invention selects a water treatment agent with good biodegradability, optimizes the compounding, and successfully prepares a non-phosphorus, environmentally friendly, and high-performance circulating water corrosion and scale inhibitor; it does not contain substances such as nitrite and phosphate that cause water pollution, is green and environmentally friendly, easy to use, and has low cost; this corrosion and scale inhibitor meets the best first-class discharge standard of GB 8978-2002.

[0012] Among the components of the scale inhibitor of the present invention, there is an excellent synergistic effect, and it has excellent corrosion inhibition and scale inhibition performance. Its corrosion inhibition rate is 99.85% and the scale inhibition rate is 98.4%. Specific embodiments

[0013] To further understand the present invention, the present invention will be described in detail below in conjunction with embodiments.

[0014] Example 1: Performance test of circulating water scale inhibitor The circulating water scale inhibitor of the present invention is prepared according to the composition and content shown in Table 1. Table 1 Formulation of circulating water scale inhibitor , The above raw materials can be purchased from the market or synthesized by oneself. Among them, the itaconic acid / 2-acrylamido-2-methylpropanesulfonic acid (IA / AMPS) copolymer and the acrylic acid-2-acrylamido-2-methylpropanesulfonic acid copolymer (AA / AMPS) are prepared by conventional methods.

[0015] Performance test method: Scale inhibition performance test Refer to GB / T 16632—2019 "Determination of scale inhibition performance of water treatment agents - Calcium carbonate precipitation method" to conduct the scale inhibition performance test of the circulating water scale inhibitor.

[0016] The blank test water without scale inhibitor and the test water after adding scale inhibitor are respectively placed in a conical flask and immersed in a constant temperature water bath at (80±1) °C for 10 h. Dry filter with a medium-speed quantitative filter paper under hot conditions. After cooling, take a certain amount of the filtrate and determine the Ca2 + concentration.

[0017] Calculation formula: .

[0018] In the formula: η represents the scale inhibition rate, c1 represents the mass concentration of Ca2 + after the test of the test solution with scale inhibitor added, c0 represents the mass concentration of Ca2 + after the test of the blank test solution without scale inhibitor added, and c represents the mass concentration of calcium ions in the water under actual working conditions.

[0019] Corrosion inhibition performance test The corrosion inhibition performance of the circulating water scale inhibitor was determined with reference to GB / T 18175-2014 "Determination of Corrosion Inhibition Performance of Water Treatment Agents - Rotating Hanging Specimen Method". The test water quality was tap water from the laboratory. The test was carried out using an SCRCC-Ⅲ type rotating hanging specimen corrosion tester. The test was set with a water bath temperature of 45 °C, a rotation speed of 105 r / min, a test duration of 72 h, and the test specimens were type I A3 carbon steel specimens with dimensions of 50 mm×25 mm×2 mm, and the total surface area of a single specimen was approximately 28 cm 2 . Five parallel specimens were arranged in each test group, and the average value was taken. The specimens were degreased, cleaned, wiped, dried, weighed and recorded before the test; after the test, the corrosion products were first brushed off with a brush, rinsed and then pickled in pickling solution for 30 s, taken out and rinsed, then put into alkaline cleaning solution and washed for 30 s, taken out, rinsed and dried, put into absolute ethanol for 3 min, taken out, dried, weighed and recorded.

[0020] Calculation formula: ; .

[0021] In the formula: μ represents the corrosion rate, m represents the mass loss value of the specimen, m0 represents the average mass loss value of the specimen in the pickling blank test, s represents the surface area value of the specimen, ρ represents the density value of the specimen, t represents the test time value, β represents the corrosion inhibition rate, μ0 represents the corrosion rate of the specimen in the blank test, μ1 represents the corrosion rate of the specimen, and 8760 is the number of hours equivalent to one year, with the unit of hours per year (h / a).

[0022] Performance test results Table 2 Performance test results of circulating water scale inhibitor , Remarks: The concentration of the scale inhibitor is 100 mg / L As can be seen from Table 2, compared with Formulas A2 - A8, Formula A1 has excellent corrosion inhibition and scale inhibition performance at the same time, with a corrosion inhibition rate of 99.85% and a scale inhibition rate of 98.4%.

[0023] In this application, tannin and sodium gluconate have both corrosion inhibition and scale inhibition performance; polyaspartic acid, sodium polyacrylate, itaconic acid / 2-acrylamide-2-methylpropanesulfonic acid (IA / AMPS) mainly play a role in scale inhibition performance; zinc sulfate, sodium metasilicate, and sodium citrate mainly play a role in corrosion inhibition performance; the components in this application cooperate with each other to play a synergistic effect, and the specific mechanism is as follows: The scale inhibition effect of the compound scale and corrosion inhibitor of the present invention is mainly achieved by the added scale inhibition monomer. The molecular structure of the scale inhibitor has multiple or various functional groups, which will simultaneously exhibit chelating, adsorption, and dispersion effects under different water quality conditions, changing the crystallization law of the scale-forming substances through physical and chemical processes, making them present a dissolved or suspended state, and preventing the formation of a large amount of scale; In the compound scale and corrosion inhibitor of the present invention, the corrosion inhibition performance mainly depends on the added corrosion inhibitor to play a leading role, and partially on the scale inhibitors that simultaneously have scale inhibition and corrosion inhibition effects to play an auxiliary role. There are electrostatic attraction and intermolecular forces between the surface of the corrosion inhibitor molecule and the metal. When the corrosion inhibitor molecules continuously adsorb on the metal surface, the formed adsorption layer greatly blocks the contact between the metal and the corrosive medium, inhibiting the occurrence of corrosion.

[0024] The embodiments described above are only used to describe the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solution of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A circulating water scale inhibitor, characterized in that It contains the following components in weight percentage: 3 - 7 parts of tannin, 3 - 7 parts of sodium gluconate, 5 - 15 parts of polyaspartic acid, 5 - 15 parts of sodium polyacrylate, 5 - 15 parts of itaconic acid / 2 - acrylamido - 2 - methylpropanesulfonic acid (IA / AMPS) copolymer, 10 - 20 parts of zinc sulfate, 10 - 20 parts of sodium metasilicate, 15 - 25 parts of sodium citrate, and 5 - 15 parts of sodium dodecylbenzenesulfonate.

2. The scale inhibitor for circulating water according to claim 1, wherein It contains the following components in weight percentage: 4 - 6 parts of tannin, 4 - 6 parts of sodium gluconate, 8 - 12 parts of polyaspartic acid, 8 - 12 parts of sodium polyacrylate, 8 - 12 parts of itaconic acid / 2 - acrylamido - 2 - methylpropanesulfonic acid (IA / AMPS) copolymer, 13 - 17 parts of zinc sulfate, 13 - 17 parts of sodium metasilicate, 18 - 22 parts of sodium citrate, and 8 - 12 parts of sodium dodecylbenzenesulfonate.

3. The scale inhibitor for circulating water according to claim 2, characterized in that It contains the following components in weight percentage: 5 parts of tannin, 5 parts of sodium gluconate, 10 parts of polyaspartic acid, 10 parts of sodium polyacrylate, 10 parts of itaconic acid / 2 - acrylamido - 2 - methylpropanesulfonic acid (IA / AMPS) copolymer, 15 parts of zinc sulfate, 15 parts of sodium metasilicate, 20 parts of sodium citrate, and 10 parts of sodium dodecylbenzenesulfonate.

4. Use of the scale inhibitor for circulating water according to any one of claims 1 - 3 in water treatment.

5. The use according to claim 4, characterized in that, For corrosion inhibition and scale inhibition.