4) Downtime and production loss


In a cooling tower, the term makeup water denotes the replacement of water lost through evaporization and bleedoff. Cycle of Concentration is a measurement of the degree to which the dissolved solid is concentrating in the recirculating cooling water system. For example, six cycle of concentration denote that the tower water has six times the concentration of dissolved solids found in the makeup water.

An effective way to control the concentration of solids before it precipitates out as scale is to remove some of the water from the tower. This systematic removal of water is called bleeding the system and the water removed is called bleedoff. Specifically, bleedoff is the amount of water that is needed to be removed from the system in order to maintain a clean heat exchange surface and minimal biological fouling. It is normally controlled through the correct number of "Cycle of Concentration" by running the TDS in the recommended range.

Scale and corrosion inhibitors, dispersants and biocides are often used in conjunction with a proper bleedoff program. IPAC CHEMICALS LTD. utilizes unique and proprietary chemicals to provide adequate protection against scaling, fouling, corrosion and biological problems.

STEAM BOILER AND CONDENSATE SYSTEMS


A boiler at pressures above that of the atmosphere generates steam. The heat is transferred from a combustion process to the water within the boiler. Steam can be used to heat a home, is used in many industrial processes and to drive turbines in power generating stations. There are four basic types of boilers; firetube, watertube, electric, and multifuel boilers.

Boiler Feedwater

Feedwater is used to replace the water that is removed from the boiler by blowdown, steam generation and processes. Feedwater is the sum of condensate return and makeup water. Under normal conditions, you would like to maximize the amount of condensate return because it has certain BTU value and has already been treated. The required feedwater purity will depend on the quantity used, the boiler design and the working pressure of the boiler.

Pretreatment

It includes clarification, sedimentation, filtration, softening, demineralization, oxidation, degasification, chlorination and evaporation. The amount of pretreatment will be dependable upon the quality of feedwater required.

-Internal Treatment
-Internal chemical treatment is to take care of any impurities in the feedwater that enter the boiler.
-A good chemical internal treatment will:
-React with any incoming hardness and prevent it from depositing on the heat exchange surface as scale.
-Generate hardness sludge and render it nonadherent to the heat exchange surface.
-Remove any traces of oxygen from the feedwater.
-Provide alkalinity to passivate the boiler surface.
-Provide antifoaming activity to permit a reasonable cycling up of dissolved and suspended solids.
-Phosphates, chelants and polymers are used to condition calcium and magnesium hardness. Hydroxide is used to condition sludge, remove magnesium hardness, passivate boiler surface and solubilize silica impurity.
-Sludge conditioners such as natural organics (lignin and tannin) or synthetic polymers are used to condition the reacted hardness.
-Oxygen scavengers such as sulfite or hydrazine are used for feedwater oxygen removal.
-Antifoam is used to reduce foaming tendency of high solids boiler water.

Neutralizing and filming amines are used to protect the steam and condensate lines by either reacting with carbonic acid when CO2 dissloves in the condensate, or by laying down a hydrophobic layer, preventing contact among the condensate lines, carbonic acid and oxygen.


POWER TECHNOLOGY

Scale inhibitors

Scale inhibitors are used to prevent the precipitation of calcium carbonate, calcium sulphate, calcium oxalate, and many mixed salts containing calcium and barium ions found in a wide variety of industrial applications. Products are available to use in those hard-to-treat high pH, high dissolved solids applications (e.g. green liquid) where conventional scale inhibitors fail. The feed point should be as close as possible, upstream, from the problem area.

Fire-Side Additives

Fire-side additives are used in kraft recovery boilers, in sulphite mills burning concentrated red liquor and in all hog fired boilers. The additives contain metallic salts which elevate the melting point of fly ash and prevent it from sticking to the boiler tubes. In addition, the bottom ash from hog fired boilers is conditioned to make it more friable and easy to remove.

Dust Control

Dust suppressants are used in areas where dust is created and where it poses health risks and/or contamination of adjacent property. Successful applications include wood chips, hot fly ash, ores, and coal. Residual treatment remains to prevent further dust generation at transfer points and other areas of high turbulence.

H2S Control

Removal of hydrogen sulphide and mercaptans from process streams, waste streams and gas streams is accomplished using a propriety amine-based product. Unlike removal with caustic solutions, which is reversible when the pH is reduced, our product reacts chemically with the H2S or mercaptans to give a product which is readily biodegradable and is unaffected by addition of acid.

Ion Exchange Resins

Ion exchange resins are available for a full range of applications including condensate polishing and raw water softening and deionization. Resins include strongly acidic cation exchanges and strongly basic anion exchange resins in gel and porous matrices. Weakly acidic cation exchangers and weakly basic anion exchangers are also available in porous or highly porous matrices.

Green Liquor Clarification

Anionic and cationic polyacrylamides can be used for clarification of waste and process streams, including clarification of green liquor in kraft mills.

Lime Mud Additives

Lime mud additives improve the pre-coat filter mud washing operations in kraft mills. They give higher mud solids and better displacement washing on the pre-coat. The better washing reduces soda losses to the kiln, and also lower the sulphide levels in the mud, which leads to lower TRS emissions. The higher mud solids reduces the energy required in the kiln and gives a better, more uniform lime product.

De-Icer

The de-icer, cold weather release agent, is used in chip silos and fines bins to alleviate/reduce hang-up. It can also be used on smooth or ribbed chip conveyor belts, and in chip-trucks and railcars to prevent the contents from freezing to the wall and floor of the vehicle.