HEDP (1-hydroxyethylidene-1,1-diphosphonic acid), as a commonly used water-soluble scale inhibitor, has the following characteristics:
1. chaical stability: HEDP has good chaical stability, even at high taperature conditions can raain stable, will not occur thermal degradation.
2. Scale inhibition efficiency: HEDP can effectively inhibit the deposition of calcium carbonate (CaCO3) and other scale. Experiments show that even at a very low concentration (such as 5 mg/L), HEDP can achieve a high inhibition rate.
3. pH effect: The thermal decomposition characteristics of HEDP are different under aerobic and anaerobic conditions, but pH has little effect on its thermal decomposition.
4. Influence of environmental conditions: taperature has a greater influence on the scale inhibition ability of HEDP, and the scale inhibition effect of HEDP is better when the concentration of calcium ions and bicarbonate ions is lower.
5. Long-term effectiveness: HEDP can provide long-term scale inhibition protection. In oilfield applications, HEDP can effectively protect oil wells and production equipment from CaCO3 deposition and has a long effective period.
6. Adsorption and desorption properties: The contact layer formed by HEDP on the rock surface resists elution, which makes its desorption process in the reservoir rock slow, thus prolonging the effective action time of the scale inhibitor.
7. Environmental friendliness: HEDP, as a green scale inhibitor, is renewable, ecologically acceptable, biodegradable and environmentally friendly.
8. Compatibility: In the petroleum industry, HEDP needs to be compatible with other chaical additives to enhance oil recovery and should not initiate corrosion or be affected by corrosion products, as well as being compatible with corrosion inhibitors.
These properties make HEDP an effective scale inhibitor for industrial water treatment, widely used in circulating cool water systas, desalination equipment, heat exchangers, and oil and gas production equipment.