Liqui-Cel® Membrane Contactors are used for degassing liquids. They are most commonly used for O2 removal from water and CO2 removal from water, but they are also capable of controlling a variety of other dissolved gasses as well, such as Nitrogen. Membrane technology has displaced vacuum tower, forced draft deaerator, and oxygen scavengers around the world for the past 20 years.

Liqui-Cel®, SuperPhobic®, MiniModule® and MicroModule® Membrane Contactors are used extensively in the microelectronics, pharmaceutical, power, food & beverage, industrial, photographic, ink and analytical/research/laboratory markets.

CORROSION CONTROL
One of the key benefits of installing a Liqui-Cel® Membrane Contactors to control dissolved gasses is to protect piping and system components from oxidation. Replacing corroded equipment and old piping is costly and time-consuming. By adding a small compact membrane degassing system, the expected lifetime of metal components can be extended and plant downtime is minimized.

Liqui-Cel® Membrane Contactors have become the preferred technology for controlled removal of oxygen and carbon dioxide from water for corrosion control. Competing technologies, such as oxygen scavengers and forced draft deaerators are not as environmentally friendly and lack the efficiency of a membrane contactor system.

Oxygen scavengers require the handling, disposal and storage of chemicals, which can be problematic given today's emphasis on environmental concerns. Liqui-Cel® Membrane Contactors do not require chemicals to operate.

Older forced draft systems cannot remove CO2 to under 5 ppm. However, Liqui-Cel® Membrane Contactors can remove CO2 to 1 ppm. Degassing contactors also operate in a completely closed system so there is no risk of introducing contaminants into the water system.

MICROELECTRONICS/FLAT PANEL
The microelectronics industry has used Liqui-Cel® Membrane Contactors for over 15 years to remove oxygen and carbon dioxide from DI water used in semiconductor wafer manufacturing processes. Liqui-Cel Contactors can easily remove dissolved oxygen down to 1 ppb and dissolved carbon dioxide down to 1 ppm.

Semiconductor wafers and flat panel displays go through a multi-step process where layers are photo exposed and developed. As each layer is processed, ultrapure water is required to wash the residual processing materials from the wafer. If gasses are present in the water they can deposit on the surface of the wafer and cause a defect on the wafer surface.

Additionally, EDI and CDI have become a common technology for Ion Exchange in the semiconductor industry. These technologies operate more efficiently if the dissolved CO2 is first removed from the water. Excess CO2 in the water will load the EDI and require the installation of more EDI stacks than are necessary. Additionally CO2 loading negatively impacts the silica and boron outputs of the EDI/CDI technologies.

Liqui-Cel® Contactors have become the degassing standard in the microelectronic and flat panel industry because they are clean, have very low extractables, and they do not negatively impact the water quality. They also have 10 times the surface area compared to a vacuum deaerator making them compact so that they can be placed virtually anywhere in a building.

PHARMACEUTICAL DEGASSING
The pharmaceutical industry requires a continuous source of purified water with a conductivity of < S/cm.?1.3 Controlling and removing the dissolved CO2 from the water will allow the water to reach this conductivity level. Historically chemical dosing with NaOH was used to control the CO2. Today people are moving away from using chemicals because of their negative impact on the environment and the safety implications of people having to handle the chemicals.

Additionally, EDI and CDI have become a common technology for Ion Exchange in the pharmaceutical industry. These technologies operate more efficiently if the dissolved CO2 is first removed from the water.

The pharmaceutical industry also requires high water quality without contamination. Liqui-Cel® systems are closed systems that do not introduce environmental contaminants into the water like an old forced draft deaerator used to do. They also replace the need to use chemical injection.

POWER/BOILER FEEDWATER DEAREATION
Controlling gas levels in the power plant and boiler feedwater systems is very critical to plant operation. It is important to remove dissolved CO2 from water and dissolved O2 from water. Both of these gasses are corrosive and they can negatively impact the boiler performance and corrode metals in the boiler system. Historically chemical injection, vacuum towers, and/or forced draft deaerators were used to remove oxygen and carbon dioxide from boiler feedwater. Liqui-Cel® Membrane Contactors, however, offer many advantages over these outdated technologies and many plants are choosing membrane systems because they are economical and compact.

Chemical injection often used in boiler maintenance puts excess deposits on metal surfaces. As chemical deposits accumulate on the boiler surfaces, the boiler has to be shut down and cleaned in a process called blow down. Blow down frequency periods increase when chemicals are injected into the feedwater. Increases in blow down frequency = higher operating costs which can be minimized with the use of Liqui-Cel® membrane degasifiers.

Oxygen removal to 1ppb can easily be achieved with membrane contactors. Compare that to a typical vacuum tower that can only achieve 7ppb. Likewise dissolved CO2 can also be removed to 1ppm. That is also lower than what a typical forced draft deaerator can produce.

There are so many other applications where Liqui-Cel Contactors have been put into operation. Most all liquids that need gasses removed from them or gasses added to them can benefit from the installation of Liqui-Cel Membrane Contactors. Membrane contactors have been used for over 15 years to control gasses in a variety of processes.

Case Studies

• TB 33: Oxygen Removal from Water to 3 ppb at IMEC
• TB 38: Chemical-Free Membrane Degassing in Pharmaceutical Plants
• TB 45: Degassing Boiler Feed Water In China With Liqui-Cel® Membrane Contactors
• TB 46: Membrane Contactors Improve Electrodeionization (EDI) Performance
• TB 47: Nuclear Power Plant Uses Liqui-Cel® Membrane Contactors for Corrosion Control and Liquid Degassing
• TB 50: Taiwan O2 CO2 Removal Case Study
• TB 56: Power Plant in Thailand Uses Liqui-Cel® Membrane Contactors to Remove CO2 From Water
• TB 57: Rokeby Generating Station Saves 50% in Capital Expense by Using Liqui-Cel® degasifiers to Remove CO2 from water
• TB 19: Improving The Outlet Water Quality Of An RO Membrane – Electrodeionization (EDI/CDI)* System Using Liqui-Cel Membrane Contactors
• TB 72: Chinese Chemical Plant Optimizes Water Treatment By Replacing Double Pass RO With A Single Pass RO And Liqui-Cel® Contactor System

Technical Papers

• Intro to Membrane Contactors
• Boiler Feed Water Degasification Using Membrane Contactors—New Methods For Optimized Performance
• CO2 -- Liqui-Cel® Contactors compared to Forced Draft Deareators

To learn even more about our experience in the water industry visit our web site at www.liqui-cel.com.