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Energy Savings through Internal Flows in Stock Tank

Energy Savings through Internal Flows in Stock Tank
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Energy Savings through Internal Flows in Stock Tank

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Energy Savings through Internal Flows in Stock Tank Introduction Paper stock normally contains more than 95 % of water. This means that a mill which produces 100,000 tons per year must handle about two million cubic meters of stock. All this stock is pumped from the beginning of the process to its end through several tanks. And the filtrate water, about 95 % of that two million cubic meters, will also be pumped in the opposite direction back to the beginning of the process. For all this, a considerable amount of pumping energy is needed, both for transfer pumping and for internal pumping in...

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Energy Savings through Internal Flows in Stock Tank - 3

Influence of shaft length The low pressure zone between the propeller and the tank causes an internal flow. A lot of energy can be lost if the tank/agitator configuration is not taken into consideration. If the propeller is very near the tank wall, the agitator loses much of its pumping capacity due to the throttled flow behind the propeller. Most side entry agitators have too short a shaft as we can see in Figure 2. Figure 3 shows a modern SALOMIX™ agitator with a long shaft so that the propeller can work with high efficiency. Bottom fillets, dilution Tank bottom fillets play an important...

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Energy Savings through Internal Flows in Stock Tank - 4

Dilution High density stock is diluted before being pumped out of the tower. To make the dilution process most effective, Sulzer recommends the use of DILCO, a dilution cone. The dilution water is pumped and blown through the DILCO into the center of the propeller where the turbulence is highest and thus mixing of the water and stock is also at its best, Figure 4. By using DILCO, dilution can be carried out with less energy, and sometimes even a smaller agitator can be selected. Upper part of a tower When we talk about agitation in a stock tower, we must understand that there is a border...

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Energy Savings through Internal Flows in Stock Tank - 5

Under level charging Some large storage towers are normally operated at a rather low level so that the inlet pipe enters the tower through the tower roof. The pump lifts the stock all the way up and then it is allowed to fall down 10 maybe 30 meters depending on the height of the tower and the operational stock level. When the stock finally hits the surface, the splashes of stock mix a lot of air into the storage zone. Later on in the system, this air must be removed by some energy consuming way. A lot of energy is wasted just by pumping the stock onto the roof of an almost empty tower,...

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Energy Savings through Internal Flows in Stock Tank - 6

www.sulzer.com ppi-info.pumps@sulzer.com E00527 en (4) 2.2014, Copyright © Sulzer This brochure is a general product presentation. It does not provide a warranty or guarantee of any kind. Please, contact us for a description of the warranties and guarantees offered with our products. Directions for use and safety will be given separately. All information herein is subject to change without notice.

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