Demineralization ( DM ) Water Plants

Advancing Water Treatment: Demineralization Water Plants

In the realm of wastewater treatment and water purification, precision and efficiency are paramount. Hydroflux Engineering Pvt Ltd, with over a decade of experience, stands at the forefront of this industry, serving New Delhi and Mumbai with a wide array of cutting-edge water and wastewater treatment systems. Our comprehensive offerings include ETP, STP, DM, RO, and Water Softener Plants. In this article, we delve into the intricate world of demineralization (DM) water plants, a vital component of our repertoire.

Demineralization in DM Plants

Demineralization, or DM, is a process that excels at eliminating dissolved solids and mineral salts from water through the utilization of ion exchange. This highly effective method is employed in various industrial water purification processes, encompassing a wide spectrum of applications, from drinking water to industrial processes like steam generation and power production.

Two-Bed Deionization DM Plants

Two-bed deionization DM plants are a key solution for removing negatively-charged constituents, primarily calcium and magnesium ions, in a process commonly referred to as “softening.” These plants are adept at reducing calcium bicarbonate concentration to a range of 0–60 mg/L, making them an essential asset for water treatment. Additionally, they efficiently remove boron from the system, contributing to the overall purity of the water.

The core of two-bed deionization involves two containers, one housing a hydroxide-based cation-exchange resin, and the other comprising a strong base anion-resin. This combination ensures a thorough demineralization process, offering water of exceptional quality.

Mixed-Bed Deionization in DM

Demineralization reaches its zenith with mixed-bed deionization systems. This technique involves passing water through a single column containing both cation and anion-exchange resins, a configuration commonly known as a “Mixed-Bed Deionizer” (MBD). By amalgamating these resins, it becomes the most prevalent and effective method of demineralization.

The process is intricate; the stream is initially subjected to a strong acid cation resin, which sequesters dissolved cations. The mineral acid solution then undergoes further treatment in another demineralization resin bed. Here, anions are removed, and hydrogen atoms are released, resulting in a neutral pH product.

Electrodeionization in DM Plants

Electrodeionization (EDI) is a revolutionary technology that employs electro-regeneration to remove ions from water via ion exchange resin, obviating the need for chemical regeneration and minimizing downtime. Unlike traditional mixed-bed polishers, EDI devices produce ultrapure water with low conductivity. The effectiveness of this process is contingent upon the initial feed water quality, making it a superior choice for certain applications.

A significant distinction between conventional ion exchange and electrodeionization lies in the degree of purification. With traditional ion exchange, the ionic purity of the product water is constrained by the total number of ions captured by the resins. EDI, however, offers a level of purity unparalleled in the industry.

Major Applications of DM Plants

The applications of DM plants are far-reaching, extending to numerous industries and processes. One of their fundamental roles is the removal of ions and salts from raw water. During service, cations migrate upward within the resin bed, while sodium ions move in the opposite direction. This interplay results in the production of a caustic substance, elevating both the pH and conductivity of the treated water.

A typical demineralization water treatment plant is structured around a single unit and column. The initial unit features a high-capacity, highly acidic cation exchange resin, which reacts with ions in hard water to generate an acid. The succeeding vessel absorbs this acid, ultimately yielding exceedingly pure water with minimal dissolved solids.

Frequently Asked Questions (FAQ)

What Are the Basic Components of a Demineralization Plant?

A demineralization plant is composed of a highly efficient cation-anion exchanger and a deionizer. Raw water traverses a cation resin bed during the process, where sodium ions dissolve into the liquid and are subsequently removed from the waste stream by an anion column. This procedure restores the pH level and conductivity of the wastewater. Strong acid cation exchangers, or SAC resins, are the preferred choice for eliminating mineral salts in such plants, ensuring that conductivity remains extremely low.

What is the difference between the RO plant and the DM plant?

In simplified terms, RO (Reverse Osmosis) plants yield deionized water, devoid of minerals, while DM plants focus on eliminating minerals. Both are designed to eliminate contaminants from water, preventing scale formation and metal oxidation. However, DM plants offer even higher water purity compared to RO plants, are more cost-effective, and require less storage space, making them an advantageous choice for industrial applications.

What is the use of DM plants in thermal power plants?

DM plants play a critical role in thermal power plants by safeguarding against corrosion. These plants filter water to remove metals, preventing scale formation and metal oxidation in high-pressure boilers. They ensure that the feedwater for steam generation is free from TDS (Total Dissolved Solids), a crucial factor in maintaining the efficiency and quality of the power generation process.

What is water demineralization?

Water demineralization is a process designed to remove dissolved salts and impurities from the water supply, resulting in water with a pH level close to 7. This process finds application in various areas, including car battery maintenance and cooling systems, where the absence of certain ions in the water enhances heat transfer and reduces corrosion.

What is the pH of Demineralised (DM) water?

Demineralized water, or DM water, typically has a pH of around 7.0, making it neutral. However, the pH level can vary based on factors such as the presence of dissolved carbon dioxide, which can lead to slightly acidic conditions. It is important to note that DM water is not intended for human consumption due to its lack of essential minerals and slightly acidic nature.

Why DM water is used in the boiler?

The use of DM water in boilers is vital to prevent scale formation and corrosion. DM water effectively removes dissolved salts and impurities, ensuring that the feedwater for boilers is free from TDS. This not only improves boiler efficiency but also enhances the overall quality of products manufactured in industrial settings.

Can We Drink Demineralized Water?

Demineralized water, while stripped of minerals and salts, is not recommended for human consumption. It lacks essential minerals, has a pH level below the ideal range, and may not provide adequate nutrients. Furthermore, its slight acidity makes it unsuitable for drinking or culinary purposes. It is important to opt for drinking water with a balanced mineral content.

What is regeneration in the DM plant?

Regeneration in a DM plant involves converting strongly acidic resins to the basic form, OH-. This process is typically performed using strong electrolytes and results in a top layer of resin bed with lower contamination levels than the bottom layers. Regeneration is essential to maintain the efficiency and functionality of DM plants.

How do you convert RO water to DM water?

Converting RO water to DM water can be achieved by selecting the appropriate type of RO membrane and employing a remineralization filter when necessary. RO membranes have small pores that trap contaminants, resulting in water with low mineral content.