Exploring the Benefits of Carbonic acid Injection System (CISx®)
A Cost-effective & Efficient Technique for pH Correction & Remineralisation in Desalination Plants
Author: Keshav Goela      Posted on: 17-12-21

The rising impact of climate change, growing population, and industrial needs are putting stress on the world's natural resources. As water scarcity rises, so do the challenges of supplying potable water to millions of people across the planet. Desalination and water reuse play a crucial role in solving the pressing water challenges of today.

A significant challenge with desalinated water is that it is devoid of minerals once it passes through the RO membranes, thereby making it chemically unstable. Remineralisation is essential to eliminate these adverse effects.

An effective and widely accepted way to remineralise desalinated water is to inject it with CO2 (Carbon Dioxide). Calcium is reintroduced into desalinated water to create the needed carbonate/bicarbonate balance followed by the addition of an acidifier such as CO2 (Carbon Dioxide) to correct the pH.

CO2 is quickly becoming the gold standard of safe pH control in water treatment plants where mild acidification is required. Compared with mineral acids, CO2 is safe to use, easily controllable, effective, and if drinking water is the goal, it has no foul sulfur smell. It requires less equipment, low monitoring costs and zero handling costs.

CO2 Injection methods

Carbon dioxide is introduced into treated water using various techniques such as CO2 gas Injection System (CISe) and Carbonic acid Injection system (CISx). Let's compare these two popular carbon dioxide injection methods and help you find the right one that fits your needs.

What is CISe®?

It's a safe, economical, and eco-friendly method of injecting carbon dioxide as microbubbles into the treated water. In this method, gaseous carbon dioxide contact surface with water is increased to enhance the solubility into the water stream as per Henry´s law.

• Offers good solubility and pH reduction for various applications for industrial or municipal applications such as re-carbonation, desalination pre, and post-treatment, disinfection, or flocculation.

• Ideal for applications where medium efficiency is sufficient or when the water process conditions are not demanding.

• Requires external absorbers and degassers for proper dissolution.

What is CISx®

The CISx® is a Carbonic acid Injection technology that offers superior CO2 dissolution with guaranteed high efficiency. An advanced technology compared to the CISe®.

Salient Features:

• Accurate pH control

• Maximum conversion efficiency

• Quick response for unstable water (flow and pH)

• Tight control over water pH and LSI (Langelier Saturation Index)

• Protects piping and other downstream equipment: No free CO2

• Skid-mounted for quick, easy, and safe installation on site

• Durable stainless-steel construction

• Does not require external equipment such as absorber and degassers

Why choose CISx® over CISe®?

At GAS LAB, remineralisation techniques for desalination plants is one of our core expertise. We carry a thorough understanding of upstream and downstream processes and have developed various techniques with the intention of enhancing the overall efficiency of your desalination system and minimizing the total cost of ownership.

Carbonic acid Injection System (CISx®), offers an enhanced dissolution efficiency standing at a minimum of 95%, ensuring the optimal consumption of CO2 used for remineralization.

Let us illustrate the efficiency of this system with an example: Assume your desalination facility is located in the GCC and requires 100-kg/h CO2 to be absorbed by water. With our CISx® technology, you can cut your carbon dioxide requirements by a significant 15%, i.e. 15kg/h of CO2 (which is around 131,400kg/year). Even more, if the system is poorly designed.

Besides reducing the amount of CO2 required, the CISx® technology also offers other benefits such as accurate pH control, faster reactions and additional indirect savings due to optimization of pH-sensitive chemicals.

Another huge benefit is that our system comes with an in-built mixture, thereby eliminating the need to install any external static mixers or degasifiers, further cutting down capital costs.

Carbonic Injection System (CISx®) regulates the pH balance of water with the fastest possible chemical reaction due to its liquid-liquid interface, providing an optimized chemical reaction, and an accurate pH & LSI control. Our trained engineers can assist you with extensive guidance to help ensure your process runs smoothly from installation to operation.