Zylon Backwash Filtration System

Summary

Product Identification

The Zylon™ Backwash Filtration System is designed for one-step brine polishing without a pre-coat. It is described as a cost-effective solution that replaces conventional clarifiers, sand filters, and pre-coat systems for producing crystal clear, high-purity brine.

At its core, the system utilizes the ultra-high-efficiency GORE® Filter Sock, made from expanded polytetrafluoroethylene (PTFE) media, which provides filtration to the sub-micron level.

Key Features & Benefits

• Eliminates Conventional Systems: Removes the need for clarifiers, sand filters, and pre-coat systems.
• Reduces Waste Discharge: Eliminating the pre-coat step reduces solids discharge to waste treatment plants by more than 50 percent.
• Proven Technology: Based on expanded PTFE membrane filter technology, successfully used in thousands of applications over 25 years.
• Zero Bypass: The absence of pre-coat eliminates the chance for filter aid bleed through.
• Minimal Maintenance: Designed without moving parts, filter-aid holding/mixing tanks, metering pumps, and extra piping.
• GORE® Filter Socks: Offer fine pore size, a non-stick PTFE surface, enabling one-pass submicron filtration with efficient in-place cleaning.
• Simple, Efficient, In-Place Cleaning: Controlled back pulsing and a patented element configuration ensure 100% regeneration of the filter media.
• Tolerates Upsets: Accommodates upsets in flow or solids concentration of the brine without affecting filtered brine quality or leading to long-term media blinding.
• Patented Support Tube Elements: Made of chlorinated polyvinyl chloride (CPVC), these elements ensure equal flow distribution, high flow rates, and optimal cleaning, and are easily inspected and replaced.
• Greater Capacity: Elimination of the pre-coat step allows the filter to be online longer, processing more brine.

Operation Principles

The Zylon System consists of filter support tubes covered with tubular membrane filter elements, mounted in a tube sheet within a vertical filter tank. The lower part of the vessel features a coned bottom for densifying solids and minimizing brine loss.

Filtration Process: Brine enters the feed zone below the tube bundle. It passes through the tubular membrane filters, collecting suspended solids (detrimental to ion exchanger units) on the membranes as a filter cake. Polished brine then flows upward to the dome and exits to the ion exchange system or holding tank.

Cleaning Process (Backwash): When a pre-determined pressure drop is reached, the inlet and outlet valves close. The filter vessel is partially drained. A precise volume of filtrate from the dome is then forced into the filter candles by instantly expanding air from a separate air tank. This reverse flow, or back pulse, causes the flexible filter socks to expand, completely removing the filter cake. Continued back-flow flushes and regenerates the tubular membrane filters. The concentrated solids are collected in the conical bottom and purged in a controlled manner, eliminating brine waste.

The GORE® filter socks consist of expanded PTFE membranes laminated to strong felt supports, with filtration occurring on the membrane surface, effectively removing submicron particles. The membrane has a micro-porous structure with controlled porosity for specific filtration requirements, resulting in fine particle retention and excellent cake release.

Cost Comparisons

For a typical system with a flow rate of 1000-1200 gpm:

• Conventional Brine Treatment: Approx. $5.2M total
  • Clarifier: $2.0M
  • Set of sand filters: $1.3M
  • Pre-coat system: $1.9M
• Zylon System: Approx. $2.0M
• Capital Savings (approx.): $3.2M

Relative Capital Cost: The Zylon System represents 50% of the capital cost of a conventional brine system. Relative Floor Space: The Zylon System requires 25% of the floor space compared to a conventional system. Precoat Cost (Purchase, Handling, Disposal): The Zylon System has 0% of the precoat cost compared to a conventional system.

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Disclaimer: This summary is based on the provided text extract and may not include all figures, footnotes, or the latest revisions present in the official OEM PDF. For contractual data and complete specifications, the official OEM PDF revision used on the project must be consulted.

Official datasheet (PDF)

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