Water Treatment for Boiler Feed
Introduction
Generally, boilers are used in industry to generate steam or hot water which in terms of generating power and heat for various applications. These days, modern boilers require High-Quality Water to operate efficiently, but such water can never be obtained from any of the natural water sources. The presence of impurities in the water makes it unfit to use in boilers. Therefore, water purification systems must be needed for boiler feed makeup water.
ROTEK has been supplying water treatment systems for boiler feed for the past 2 decades. There are generally 3 methods to treat boiler feed water depending on the type of boiler that the customer is using.
ROTEK uses a variety of water purification technologies including:
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Pretreatment -> Water Softening (for Hot Water boiler)
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Pretreatment -> Reverse Osmosis System (for Industrial Steam boiler)
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Pretreatment -> RO System -> EDI or DI Systems (for Power Plant)
Concerns
Feed-water purity is a matter both of the quantity of impurities and the nature of impurities: some impurities such as hardness, iron, and silica are of more concern, for example, than sodium salts. The purity requirements for any feed water depend on how much feed water is used as well as what the particular boiler design (pressure, heat transfer rate, etc.) can tolerate. Feed-water purity requirements therefore can vary widely. A low-pressure fire-tube boiler can usually tolerate high feed-water hardness with proper treatment while virtually all impurities must be removed from water used in some modern, high-pressure boilers.
Design Criteria
Based on the raw water quality analysis, we will provide our design suggestions followed by the 4 major treatment setups:
Filtration Systems
This section is basically responsible for filtering out most of the fine particles, heavy metals, chlorine, organic matter, bacteria, color & and odors. The filtration system usually consists of a Clino-X Multimedia Sand Filter, Activated Carbon Filter, Water Softener, Ultra-Filtration System, Anti-Scale, and Chlorination Chemical Dosing Systems.
Purification Systems
Reverse osmosis (RO) is a water purification technology that ROTEK uses most of the time for many industries. RO can remove many types of molecules and ions from solutions and is used in both industrial processes and to produce potable water. Depending on the raw water quality, if raw water TDS is below 50 ppm, then this section of the purification system may not be required as part of the design for bottled water production.
Remineralization Systems
Although RO removes everything from the water (including good and bad minerals),
however low-mineralized water has a few adverse effects:
- High corrosion potential
- Dietary deficiency causes risks of ischaemic heart and cerebrovascular disease (WHO, 2005a; WHO, 2006; Cotruvo, 2006)
The WHO recommends 10 mg/L of Magnesium and 30 mg/L of Calcium for drinking water. Therefore adding beneficial minerals to the product water is a process called demineralization. ROTEK uses natural minerals called "Camag" for adding pure Magnesium and Calcium to the product water with great improvement on the taste and pH level.
Disinfection Systems
The most common bacteria found in bottled water is Pseudomonas fluorescens, which is common in freshwater springs. It is not considered to be a health threat until you leave the bottle open for extended periods of time and the bacteria begin to react with the carcinogens in the plastic. Reducing bacteria and microbial to the minimum is the most important issue in the bottled water production business. ROTEK disinfection system consists of UV sterilizer, Nanosilver Activated Carbon, 0.2-micron filter, and ozone disinfection. With four levels of protection, the ROTEK disinfection system will make sure the bacteria level is reduced to nil before filling the bottle.