Boiler Water Treatment in Palm Oil Mills

 Having eight years of experience animate as soon as biomass-shining boilers in palm oil mills, I can accustom that boiler water treatment in palm oil mills is a inspiring task if compared subsequent to industrial boilers. Unlike industrial boilers which rely heavily in description to condensate reward and industrial water for boiler feed water makeup, the source of raw water for boiler feed water in palm oil mills comes from lake, river, or ably. Relatively not much condensate can be recovered in palm oil mills due to the high amount of unrecoverable sterilizer condensate and the application of living steam in some of the process heating. In palm oil mills, low cycle of cassette is not out of the shadowy which indicates more chemicals are wasted through blowdowns.

The raw water from natural resources is high in impurities, turbidity, dissolved gases, and mineral content. Sometimes algae, mud and oil could be say around and silica is particularly a difficulty in water from lakes, and this scenario complicates treatment added. Lack or inadequate water treatment is risky as it may cause scaling and corrosion which perform the reliability, efficiency, and broadcaster operation of the boiler.

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In general, boiler water treatment consists of outdoor and internal water treatment. External water treatment refers to conditioning boiler feedwater by removing impurities, hardness, oil, oxygen, dissolved and suspended solids, outdoor the boiler and usually lithe by mechanical means such as continuous clarifier, pressure sand filter, water softener, and deaerator. Because it is not feasible to get your hands on a do boiler feed water by outdoor water treatment, an internal water treatment, which mainly by chemical means, shall be employed. All boiler engineers must be familiar that the external treatment of boiler feedwater must be emphasized in front more chemical assistant in the boiler is undesirable.

In industrial boilers, the removal of turbidity and suspended matters is already finished by the municipal water treatment system. This is however a oscillate description in palm oil mills. The external treatment for boiler makeup (feedwater) consists of pH getting used to, coagulation, flocculation, sedimentation, filtration, water softening, and finally, deaeration. Soda ash is accrual if the pH of the water is low. Soda ash acts as pH adaptation because coagulant functions at pH ranges exceeding 5.5 to 8.0. The coagulation chemicals are dosed into the inlet pipe leading to the bottom of a continuous water clarifier. Coagulation and flocculation are the basic steps in boiler water treatment to shorten turbidity, organic substances, and color of raw water. Coagulation neutralizing the negative charges about the subject of colloid surfaces, allowing the particles to agglomerate to form floc, which is slow settling. The most common coagulants are aluminum sulfate (alum), sodium aluminate, and polyaluminum chloride (PAC). Synthetic polymers called polyelectrolites have been developed for coagulation process. Flocculation is subsidiary agglomeration of slowly-settling coagulated particles into large hastily-settling floc behind the buildup flocculant such as organic polymer (starch) or synthetic polymer such as polyacrylamide (PAM) to put in and bridge together in the midst of particles to form larger agglomerates.

From the natural resources, the water is pumped by booster pumps into the continuous clarifier to make a clean breast flocs to burning the length of. The water rises in the appearance of decreasing velocity and the resultant floc forms a sludge blanket at the upper portion of the conical section. The clarifier is blowdown periodically to remove the stuffy sludge, which arranged at the bottom even though complimentary water is transported to a sure water tank in the to the front passing through a pressure sand filter where solids escaped from the clarifier and pleasant particles are filtered and removed. Normally, the sand filter removes fine particles happening to 10 m. Sand filters normally contain sands and gravels, 100% anthracite, or assimilation of sand, anthracite, and gravel. Sufficient water reservoir is maintained in the overhead tank and if the level of water in the tank becomes low, the operation of boilers could be affected. In water softener, sodium zeolite ion-quarrel process is used to remove hardness. The take steps of a softener is to surgically remove water hardness (calcium and magnesium) using ion dispute process. Normally sodium zeolite is used and a softener would contain 30~36" of synthetic ion disagreement resin. For example, calcium bicarbonate, Ca(HCO3)2 dissolves in water and split going on to Ca2+ and (HCO3)-. In ion-dispute process, Ca2+ is removed by replacing sodium ion using resin ion-disagreement bed which is covered in the middle of Na+ ions. Here in palm oil mills, the softeners are prone to bio and iron fouling. Soft water is plus pumped into the deaerator for deaeration. The pressurized deaerator operates by allowing steam into the feed water through a pressure rule valve to desist the desired thriving pressure, and therefore temperature at a minimum of 105C. The steam raises the water temperature causing the official pardon of O2 and CO2 gases that are next vented from the system. This type can condense the oxygen content to 0.005 ppm. The water produced is oxygen-pardon so oxygen corrosion in the boiler can be avoided.

The internal treatment involves the have emotional impact ahead of reactant chemicals such as sulfite, sodium phosphate, chelates, polymers, and vitriolic, which each has vary be in in treating boiler water. To prevent oxygen corrosion, the chemical known as oxygen scavenger is unconventional. The common oxygen scavengers are sulfite, hydrazine, and DEHA. Hydrazine however should be avoided because it is carcinogenic.. Phosphate prevents scaling by precipitating calcium as calcium triphosphate or hydroxylaptite, which can be removed via blowdown.