Suspended solids are sediments or organic matter which comes along with the makeup water. If not removed prior to their entry in the boiler, they can result in multiple issues like sludge formation, foaming, corrosion, clotting etc. Methods like clarification, filtration, and chemical treatment are used to limit suspended solids from the feed water. As we have seen in the previous article, dissolved solids form scales which can be extremely difficult to be removed.
Hence, it is quite essential that they are restricted from going inside the boiler. Dissolved solids include impurities like Hardness, sulfates carbonates etc. Natural water also has silica dissolved in it which can form hard scales. Hard water can be converted into soft water by using a softener which removes these ions from the water by the process of ion exchange.
Along with this, water also has chlorides and sulfates which can be removed by the process of de-ionisation. Feed Water Treatment. Feed Water Treatment Feed water composition In order to generate steam on a constant basis, boiler should be continuously supplied with water, called as feed water. Dissolved Gases Air naturally has certain amount of dissolved gases like oxygen, carbon dioxide in it.
Suspended Solids Suspended solids are sediments or organic matter which comes along with the makeup water. Dissolved solids As we have seen in the previous article, dissolved solids form scales which can be extremely difficult to be removed.
In many cases external treatment of the water supply is not necessary and the water can be treated only by internal methods. Internal treatment can constitute the unique treatment when boilers operate at low or moderate pressure, when large amounts of condensed steam are used for feed water, or when good quality raw water is available. The purpose of an internal treatment is to. In addition, as supplementary measures an internal treatment should prevent corrosion and scaling of the feed-water system and protect against corrosion in the steam condensate systems.
During the conditioning process, which is an essential complement to the water treatment program, specific doses of conditioning products are added to the water.
The commonly used products include:. There are two general approaches to conditioning sludge inside a boiler: by coagulation or dispersion. When the total amount of sludge is high as the result of high feed-water hardness it is better to coagulate the sludge to form large flocculent particles.
This can be removed by blow-down. The coagulation can be obtained by careful adjustment of the amounts of alkalis, phosphates and organics used for treatment, based on the fee-water analysis. When the amount of sludge is not high low feed water hardness it is preferable to use a higher percentage of phosphates in the treatment. Phosphates form separated sludge particles.
A higher percentage of organic sludge dispersants is used in the treatment to keep the sludge particles dispersed throughout the boiler water. The materials used for conditioning sludge include various organic materials of the tannin, lignin or alginate classes.
It is important that these organics are selected and processed, so that they are both effective and stand stable at the boiler operating pressure. Certain synthetic organic materials are used as anti-foam agents. The chemicals used to scavenge oxygen include sodium sulphite and hydrazine. Various combinations of polyphosphates and organics are used for preventing scale and corrosion in feed-water systems.
Volatile neutralizing amines and filming inhibitors are used for preventing condensate corrosion. Common internal chemical feeding methods include the use of chemical solution tanks and proportioning pumps or special ball briquette chemical feeders.
In general, softening chemicals phosphates, soda ash, caustic, etc. They may also be fed through a separate line discharging in the feed-water drum of the boiler. The chemicals should discharge in the fee-water section of the boiler so that reactions occur in the water before it enters the steam generating area.
Softening chemicals may be added continuously or intermittently depending on feed-water hardiness and other factors. Chemicals added to react with dissolved oxygen sulphate, hydrazine, etc. Chemicals used to prevent condensate system corrosion may be fed directly to the steam or into the feed-water system, depending on the specific chemical used. Continuous feeding is preferred but intermittent application will suffice in some cases. Check also our web page about the production of high pure water through Electrodeionization EDI.
Click here for more details about deaeration deaerating heaters or membrane contractors. Contact a local reputable boiler chemical specialist, such as Garratt Callahan Company, for more information on these procedures and requirements. Pacific Northwest Customers. Nationwide Boiler Inc. Local Representatives Request a Quote How did we do?
Sell Your Boiler. Boiler Blog Nationwide Boiler Inc. Nationwide Boiler news and events, industry updates, technical resources and more. You hear it first on The Nationwide Boiler Blog! Michele Tomas. Friday, 23 January
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