Why do seawater desalination systems require special chemicals?

Seawater desalination systems inevitably face four core challenges during long-term operation. These issues will not only reduce system efficiency and significantly raise operating costs, but also cause equipment damage and unplanned shutdowns in severe cases. The

refore, the application and management of special chemicals are vitally important.

Chemical Solutions

Overview of Full-Process Chemical Application

To address the complex water quality and process challenges encountered in seawater desalination systems, specialized chemicals must be accurately dosed at all critical stages to deliver a comprehensive full-process solution and ensure stable system operation.

Core Product 1: Specialized chemicals for Reverse Osmosis (RO) systems—essential for ensuring the long-term, stable, and efficient operation of membrane systems.

01 Antiscalant

Mechanism of Action: Inhibits the deposition of sparingly soluble salts (such as calcium carbonate and calcium sulfate) on the membrane surface at the source by chelating scale-forming ions, dispersing particulates, and inducing crystal lattice distortion.

Key Advantages: Broad applicability; effective at very low dosages; chemically stable; and fully compatible with various RO membrane materials.

02 Cleaning Agent

Acidic Cleaning Solution: Targets inorganic scales (e.g., carbonates and sulfates); rapidly dissolves and removes hardness-related contaminants deposited on the membrane surface, thereby restoring membrane flux.

Alkaline Cleaning Solution: Specifically removes organic contaminants (such as oils and colloids) adhering to the membrane surface, and powerfully eliminates microbial slime and biofilm layers.

03 Biocide

Oxidizing Biocide: Represented by sodium hypochlorite (NaClO); acts rapidly and is used during the pretreatment stage, though it must be completely removed before entering the RO membrane system to prevent oxidative damage.

Non-oxidizing Biocide: Such as isothiazolinones; safe for membrane elements; allows for continuous dosing into the RO system to provide long-term control over microbial and biofilm proliferation.

Synergistic Effect: The scientific combination and standardized dosing of antiscalants, biocides, and cleaning agents create a comprehensive, full-lifecycle chemical protection system for RO operations, ensuring safe and reliable system performance.

Core Product 2: Specialty Chemicals for Thermal Desalination Systems

Chemicals for thermal desalination systems must withstand high temperatures and effectively address scaling on evaporator and heat exchanger surfaces, ensuring stable system operation in high-temperature, high-concentration environments.

01. High-Temperature Antiscalant

Application: Primarily used in Multi-Effect Distillation (MED) and Multi-Stage Flash (MSF) systems.

Key Requirements: Must remain stable and highly effective in harsh environments characterized by high temperatures (up to 120°C or higher) and high concentration factors.

Mechanism: Prevents the formation and deposition of scales—such as calcium carbonate, calcium sulfate, and magnesium hydroxide—on heat exchange surfaces through chelation, dispersion, and lattice distortion.

Product Value: Maintains high heat exchange efficiency, reduces steam consumption, minimizes the frequency of cleaning, and extends equipment service life.

SGR1134 Seawater Desalination Evaporation Antiscalant

Performance & Application

SGR1134 is formulated with multiple special surfactants and synergists. It chelates Ca²⁺ and Mg²⁺ in water and suppresses scale generation through lattice distortion. It provides outstanding chelating and dispersing effects on scales including calcium carbonate, calcium sulfate, calcium fluoride, barium sulfate and strontium sulfate produced during seawater desalination evaporation.

Superior Performance Features

SGR1134 is resistant to high temperature, alkali and salt, remains stable under high-temperature environments, and features low application dosage.

Application Scenarios

Primarily applied for scale control during the evaporation process of seawater desalination facilities.

Top Right Panel: Physical & Chemical Indicators

Bottom Right Panel: Operation & Usage Guidelines

1. Dosing Method: Transfer the agent into a plastic dosing tank (or bin). Dilute with water for convenient use, then continuously inject the chemical via a metering pump or regulating valve.

2. Recommended Dosage: Standard dosage ranges from 2–8 mg/L based on evaporated water flow. The exact dosing volume shall be adjusted according to actual water quality.

Layout Description for New Generated Image

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02. Thermal Desalination System Cleaner

Application: Chemical cleaning is required when heat exchange efficiency drops, indicating scale formation.

Target Deposits: Specifically formulated for mixed scales comprising calcium sulfate (CaSO4), calcium carbonate (CaCO3), and magnesium hydroxide (Mg(OH)2).

Product Features: Typically a composite formulation containing powerful chelating agents, penetrating agents, and dispersants capable of effectively dissolving and removing hard scale deposits.

Cleaning Results: Restores heat exchange efficiency, reduces energy consumption, and ensures stable system operation.

                                                                      Carbonate Cleaning Agent

To tackle calcium carbonate scale and metal oxide deposits formed after long-term operation of evaporators, heat exchangers and condensation units in thermal seawater desalination systems (MED, MSF, etc.), our company has developed a line of specialized descaling products.Customized for different equipment materials and scale types, these products adopt a composite formula of descaling agents, corrosion inhibitors and accelerators. They achieve highly efficient scale removal while lowering corrosion risks to equipment, quickly restore the heat exchange efficiency of facilities, and guarantee stable operation of seawater desalination systems.

SGR1231, SGR1232 and SGR1233 are a series of specialized cleaning agents developed by our company for sulfate scale and composite inorganic scale. Tailored to the structure and formation mechanism of scale deposits, the three products adopt swelling-type, dissolving-type, and dissolving-dispersing cleaning technologies respectively. They can efficiently eliminate deposits including sulfate scale and composite salt scale inside evaporators, heat exchangers and auxiliary facilities.