Process Design Scheme for High-Purity Water System in the New Materials Production Industry

1.0 Design Basis and Standards

• Product Water Use: New material synthesis, powder preparation, substrate cleaning, chemical preparation, R&D experiments, etc.

• Product Water Standards: Chinese National Standard GB/T 11446.1-2013 Electronic Grade WaterEW-I to EW-IV grades, or customized based on specific material process requirements (e.g., Resistivity ≥18.2 MΩ·cm, TOC ≤5 ppb, Particles ≤1 count/mL).

• Design Codes: Complies with relevant industry guidelines such as GMP, FDA, SEMI.

• Core Requirements: Ultra-high water purity, system stability and reliability, optimized operational costs, intelligent monitoring.

2.0 Source Water Quality and Product Water Targets

3.0 Process Flow Design

To meet the new materials industry's stringent requirements for water purity, particulates, and TOC, a comprehensive process integrating "Multi-Stage Pretreatment + Double-Pass Reverse Osmosis + EDI + Polishing Mixed Bed + Terminal Polishing" is recommended. This ensures multiple safeguards and long-term system stability.

flowchart TD
    A[Source Water<br>Municipal/Well] --> B[Raw Water Tank]
    B --> C[Pretreatment System]
    
    subgraph C[Pretreatment System]
        C1[Multi-Media Filter] --> C2[Activated Carbon Filter] --> C3[Water Softener] --> C4[Cartridge Filter]
    end

    C --> D[Primary RO System]
    D --> E[Intermediate Tank]
    E --> F[Secondary RO System]
    F --> G[EDI System<br>Electrodeionization]
    G --> H[Pure Water Tank]

    H --> I[Polishing Mixed Bed]
    I --> J[Terminal Polishing]

    subgraph J[Terminal Polishing]
        J1[UV Sterilizer] --> J2[TOC Reducer] --> J3[Ultrafiltration Unit] --> J4[Final Polishing Cartridge]
    end

    J --> K[Point of Use]
    K --> L[New Materials Production]

    M[Chemical Dosing System<br>Antiscalant/Reductant/Biocide] --> D
    N[Chemical Cleaning System] --> D & F
    O[Intelligent Control System<br>PLC+Online Instruments] --> C & D & F & G & I & J

Process Flow Step-by-Step Explanation:

Stage 1: Pretreatment System

• Purpose: Remove suspended solids, organics, residual chlorine, and hardness to protect downstream membrane elements.

• Multi-Media Filter: Removes suspended particles, sediment, and colloids ≥10 μm.

• Activated Carbon Filter: Adsorbs residual chlorine, organics, color, and odor, protecting RO membranes.

• Water Softener (Optional): Removes calcium and magnesium ions via sodium ion exchange resin to prevent RO scaling.

• Cartridge Filter: 5 μm precision filtration acting as the final safety barrier.

Stage 2: Reverse Osmosis Desalination System (Core Desalination)

• Primary RO: Removes approximately 97-99% of dissolved salts, organics, colloids, and bacteria.

• Secondary RO: Provides further desalination, producing water up to 1-5 MΩ·cm, providing ideal feed water for EDI.

Stage 3: Electrodeionization and Deep Polishing

• EDI Unit: Continuous electrodeionization + mixed ion exchange technology requiring no acid/base regeneration. It produces water with stable resistivity ≥10-15 MΩ·cm and is the core equipment for high-purity water production.

• Polishing Mixed Bed: Contains nuclear-grade high-purity ion exchange resin, elevating water quality to 18.2 MΩ·cm and providing deep removal of trace ions.

Stage 4: Terminal Polishing and Distribution

• UV Sterilizer: 254 nm wavelength for microbial control.

• TOC Reducer: 185 nm UV lamp oxidizes organics into ionic forms for subsequent polishing removal.

• Ultrafiltration Unit: Removes particles, bacteria, and endotoxins ≥0.1 μm.

• Final Polishing Cartridge: 0.1 μm or higher grade cartridge for final water quality assurance.

• Distribution System: Constructed with 316L stainless steel piping, fully automatic circulation to prevent stagnant zones and microbial growth.

4.0 Key Equipment and Design Parameters

5.0 System Features and Advantages

1. Multi-Barrier Design: Multiple safeguards from pretreatment to point of use, ensuring final water quality even with single-point failures.

2. Environmentally Friendly: EDI replaces traditional mixed beds, reducing acid/base consumption and wastewater by over 90%.

3. Intelligent Operation & Maintenance: Predictive maintenance using data analytics, real-time monitoring and alerts for key parameters (SDI, differential pressure, product water quality).

4. Modular Scalability: Flexible expansion based on capacity needs, supports future production line additions.

5. Compliance & Validation: System compliant with GMP/FDA requirements, supports IQ/OQ/PQ validation, and provides complete documentation.

6.0 Investment and Operating Cost Analysis

• Capital Investment: Primarily for RO/EDI/Polishing modules, high-grade piping, and control systems.

• Operating Costs: Mainly electricity (~1.5-3.0 kWh/ton of water), consumable replacement (membranes, resin, cartridges), periodic sanitization, and validation.

• System Recovery: Overall system recovery can reach 70-75% (via concentrate recycle to pretreatment).

• Water Conservation: Can integrate water reclamation or rainwater utilization systems to further enhance water resource efficiency.

7.0 Service and Support

• Design Support: Provide 3D layout drawings, Piping & Instrumentation Diagrams (P&ID), equipment lists.

• Installation & Commissioning: On-site guidance by professional team for system startup and performance testing.

• Training: Comprehensive training for operation, maintenance, and troubleshooting.

• After-Sales Service: Remote monitoring support, scheduled preventive maintenance, and fast spare parts response.

Summary: This scheme addresses the stringent requirements for ultra-pure water in the new materials industry by designing a technologically advanced, stable, reliable, intelligent, and environmentally friendly high-purity water production system. Through the combined process of pretreatment protection, two-stage RO deep desalination, EDI continuous polishing, and terminal multi-stage polishing, the system can stably produce ultra-pure water exceeding 18.2 MΩ·cm, meeting the needs of various high-end new material R&D and production. Before specific implementation, a complete analysis of the source water is recommended, and personalized adjustments should be made based on actual water production requirements, point-of-use distribution, and investment budget.