Spanish English Chinese

The scaling of circulating cooling water systems is a common problem encountered in industrial production. The scale can significantly reduce the efficiency of the heat exchange system. At present, the industry has adopted a method of adding a phosphorus-containing scale inhibitor to the cooling water system to prevent corrosion and scaling of the water pipe wall.

Hydroxyethylidene diphosphonic acid (HEDP) and phosphonic acid butane tricarboxylic acid (PBTCA) are two scale inhibitors widely used in the industry. The phosphorus content of PBTC acid is relatively low, only 38.2% of the phosphorus content of HEDP. Although the use of phosphorus-containing scale inhibitors has been very successful, there is no consistent method for scale inhibition mechanisms.

pipe wall scale
Calcium carbonate is the main component in scale. Calcium carbonate crystals usually have three crystal phases: calcite, vaterite, and aragonite. Crystals separated from the calcium carbonate solution at room temperature.

In recent years, in the microscopic mechanism of studying the scale inhibition effect of scale inhibitors, many researchers believe that the scale inhibition effect that can be exerted by scale inhibitors should be related to the mutual effects of their molecules on the appearance of insoluble salts.

The key effect on the scale inhibition effect is the negatively charged functional groups in the organic scale inhibitor molecules. These negatively charged groups and the positively charged calcium ions in the insoluble calcium salts can exert a strong Coulomb electrostatic effect on each other.

If the distance of the functional group is close to that of the isomorphic ion, the electrostatic attraction will cause a strong adsorption action. This hinders the further accumulation of calcium ions and carbonate ions and then inhibits the growth of calcium carbonate crystals.

The electrical properties of the HEDP molecule and the PBTC acid molecule are neutral overall, with a negative charge only at the phosphonic acid group [(HO)2OP-] and the carboxylic acid group [-COOH]. This is consistent with the theory presented earlier. Negatively charged oxygen ions are prone to strong electrostatic effects with Ca2+ on the surface of calcium carbonate.

The Following Describes HEDP and PBTCA in Detail.

HEDP is an organic phosphonic acid scale and corrosion inhibitor. It can form a stable complex with various metal ions such as iron, copper, and zinc. HEDP acid dissolves oxides on metal surfaces. It still provides excellent corrosion and scale inhibition at 250 °C. HEDP is still stable at high pH values, is not easily hydrolyzed, and is generally difficult to differentiate under photothermal conditions.

HEDP chemical has better acid and alkali resistance and chlorine oxidation resistance than other organic phosphonic acids (salts). It forms a six-ring chelate with metal ions in water, especially with calcium ions. Therefore, HEDP acid has a good scale inhibition effect and has a significant solubility effect. It exhibits excellent synergistic effects when used in combination with other water treatment agents.

PBTC acid full name 2-phosphonobutane-1 2 4-tricarboxylic acid. CAS No. 37971-36-1. Molecular formula C7H11O9P. Relative molecular mass: 270.13.

PBTCA (2-phosphonobutane -1 2 4-tricarboxylic acid) is a new generation of phosphocarboxylic acids created in the 1980s. It is currently popular with low phosphorus corrosion and scale inhibitor. PBTCacid is now widely used in industrial production. It is composed of a dialkyl phosphite, a dialkyl maleate, and an alkyl acrylate as raw materials, and is subjected to one-step repeated reaction under strong basic catalytic conditions. The yield was 87.7%.

PBTC chemical is widely used in circulating cooling water systems and oilfield water injection systems. PBTCA has excellent functions of blocking calcium carbonate and calcium phosphate scale. It has a common stability effect on zinc ions and the like. Zinc ions can be stabilized in circulating cooling water having a pH of 8.3. It is also stable at a pH of 9.5. This makes it possible to formulate zinc-containing alkaline formulations.

PBTC acid also has outstanding high-temperature resistance, oxidation resistance, and chlorine stability. It has a good dispersing function for circulating water with high turbidity and high iron.

After professional research and analysis of the effects of HEDP and PBTC in the circulating cooling water system, the final solution needs to be determined according to the environment. Avoid losses due to mistakes in selection.

Leave a Reply

Your email address will not be published. Required fields are marked *

01Nov 2019

Abstract: Maleic anhydride is used as raw material, sodium tungstate is used as catalyst, hydrogen peroxide is used as a cyclizing agent and Ca(OH)2 is used as an initiator. Polyepoxysuccinic acid (PESA) water treatment chemical was prepared by aqueous solution polymerization. PESA is a green, highly effective scale inhibitor. The optimal synthesis conditions were determined […]

31Oct 2019

Benzotriazole Corrosion Inhibitor Analysis in the Action Mechanism Abstract: This post introduces the properties and mechanism of benzotriazole corrosion inhibitors. The synergistic action of benzotriazole and imidazole better illustrates the progress of the sustained release. Combined with the corrosion example of copper in sodium chloride solution to illustrate the corrosion inhibition of triazole compounds. Keywords: […]

17Sep 2019

Abstract: A water-soluble copolymer scale inhibitor was synthesized from acrylic acid (AA) and 2-acryloyl-2-methyl propane sulfonic acid (AMPS). The scale inhibition and dispersion properties of the copolymer were determined. The effects of monomer ratio, reaction temperature and molecular weight modifier on the scale inhibition performance of the copolymer were investigated. Keywords: sulfonic acid, copolymer, scale […]

09Sep 2019

This article describes the commonly used experimental methods for assessing the biodegradability of polyacrylic acid polymers. It is recommended to use the carbon dioxide (PCD), oxygen consumption (COD) and infrared spectroscopy images of biodegradation to comprehensively analyze the biodegradability of polyacrylic acid polymers. The volume of the bioreactor is 2L, the concentration of the tested […]

23Aug 2019

2-Hydroxyphosphonoacetic acid is a good scale inhibitor. Its appearance is a dark brown liquid with a molecular formula of C2H5O6P and a relative molecular mass of 156.03. The preparation method generally has the following three methods. Method One 16.3 parts (0.11 mol/L) 50% aqueous solution of dihydroxyacetic acid (hydrated glyoxylic acid) and 8.2 parts (0.1 […]

30Jul 2019

Through the static scale inhibition test, we studied the scale inhibition performance of PBTC and HEDP on calcium carbonate scale under low-temperature conditions (2°C-15°C). The results show that the scale inhibition performance of PBTC and HEDP on calcium carbonate scale is good at 2°C-15°C. The initial calcium ion + alkalinity has a great influence on […]

27Jun 2019

The full name of DBNPA is 2-2-dibromo-3-nitriloproion amide. It is a broad-spectrum and efficient industrial fungicide. DBNPA is used to prevent bacteria and algae from growing in papermaking, industrial circulating cooling water, mechanical lubricants, pulp, wood, paint, and plywood. 2-2-Dibromo-3-Nitrilopropionamide (DBNPA) is currently popular at home and abroad. Organic bromine fungicides. Sterilization mechanism of DBNPA […]

26Jun 2019

1. The Introduction of Reverse Osmosis Chemicals The reverse osmosis chemical, IRASD-200 is a highly effective scale inhibitor developed for reverse osmosis (RO) systems. During the water treatment, dirt and iron scale are formed on the reverse osmosis membrane. They can degrade the performance of the water treatment system. Contaminants and deposits that accumulate on […]

25Jun 2019

2-mercaptobenzothiazole (MBT) is an important variety of thiazole rubber vulcanization accelerators. At the same time, it is also an important auxiliary agent for oxidation and corrosion resistance. 2-MBT is a pale yellow powder or granule. It has an unpleasant smell. The melting point is above 173.0°C. The relative density is 1.41 to 1.48. 2-mercaptobenzothiazole is […]

25Jun 2019

1. Active component (1-hydroxyethylidene-1 1-diphosphonic acid) content. 1.1 Oxidative decomposition method The active component of the finished product, 1-hydroxyethylidene-1 1-diphosphonic acid, and impurity phosphorous acid. Under appropriate oxidative decomposition conditions, both are converted to n-phosphonic acid. Then measure the data in a corresponding method. The total amount of n-phosphonate represents the amount of phosphinate which […]