Vertical Slurry Pumps

Vertical slurry pumps are particularly popular in froth handling circuits. To handle the combination of soUds, air, and liquids, a double suction impeller is often recom-... 

FIGURE 8-41 Vertical slurry pump with a recessed impeller. This pump is suitable for carbon transfer in gold cyanide circuits and for wastewater treatment applications. The addition of a cutter (rotor and stator) renders this pump particularly suitable for certain applications such as sewage treatment and newspaper recycling plants. 

An emergency pond needs its own pumping system. It can consist of a vertical slurry pump floating on a pontoon or barge (Figure 12-8). The sump pump feeds a booster pump that redirects the slurry back to the pipeline pump box or back to the thickeners. 

This is very low. and since the engineer must avoid cavitations, he or she may consider the use of a submersible slurry pump or a vertical cantilever pump instead of a horizontal pump on the shore. 

One of the most efficient implementations of the slurry process was developed by Phillips Petroleum Company in 1961 (Eig. 5). Nearly one-third of all HDPE produced in the 1990s is by this process. The reactor consists of a folded loop with four long (- 50 m) vertical mns of a pipe (0.5—1.0 m dia) coimected by short horizontal lengths (around 5 m) (58—60). The entire length of the loop is jacketed for cooling. A slurry of HDPE and catalyst particles in a light solvent (isobutane or isopentane) circulates by a pump at a velocity of 5—12 m/s. This rapid circulation ensures a turbulent flow, removes the heat of polymeriza tion, and prevents polymer deposition on the reactor walls. 

During operation the slurry is pumped under pressure into a vessel that is fitted with a stack of vertical leaves that serve as filter elements. Each leaf has a centrally located neck at its bottom which is inserted into a manifold that collects the filtrate. The leaf is constructed with ribs on both sides to allow free flow of filtrate towards the neck and is covered with coarse mesh screens that support the finer woven metal screens or filter cloth that retain the cake. The space between the leaves may... 

By virtue of their construction, diaphragm pumps cannot be used for high pressure applications. In the Mars pump, there is no need for a diaphragm as the working fluid (oil), of lower density than the liquid to be pumped, forms an interface with it in a vertical chamber. The pump, which is used extensively for concentrated slurries, is really a development of the old Ferrari s acid pump which was designed for corrosive liquids. 

Spray dryers are normally used for liquid and dilute slurry feeds, but can be designed to handle any material that can be pumped. The material to be dried is atomised in a nozzle, or by a disc-type atomiser, positioned at the top of a vertical cylindrical vessel. Hot air flows up the vessel (in some designs downward) and conveys and dries the droplets. The liquid vaporises rapidly from the droplet surface and open, porous particles are formed. The dried particles are removed in a cyclone separator or bag filter. 

You have a granular solid with SG = 4, which has particle sizes of 300 pm and smaller. You want to separate out all of the particles with a diameter of 20 pm and smaller by pumping water upward through a slurry of the particles in a column with a diameter of 10 cm. What flow rate is required to ensure that all particles less than 20 pm are swept out of the top of the column If the slurry is pumped upward into the bottom of the column through a vertical tube, what should the diameter of this tube be to ensure that none of the particles settle out in it ... 

A direct liquefaction technique, the SRC process involves mixing dried and finely pulverized coal with a hydrogen donor solvent, such as tetralin, to form a coal-solvent slurry. The slurry is pumped together with hydrogen into a pressurized, vertical flow reactor. The reactor temperature is about 825°F (440°C) and pressures range from 1,450 to 2,000 psi. A residence time in the reactor of about 30 minutes is required for the carbonaceous material to dissolve into solution. From the reactor, the product passes through a vapor/liquid separation system. The slurry solids remaining in the reactor are then removed and filtered. Various filtration techniques have been developed to remove solids from recoverable oil. 

In large-scale blasting processes in open pit mining and quarrying, rows of nearly vertical boreholes are drilled parallel to the quarry face the diameter of each borehole is 3-8 in. (in Germany more often 3-4 in.), while the borehole length is over 10 m. The holes are filled with explosive and stemmed. -> Free-flowing Explosives or pumped -> Slurries can be applied. 

Figure 15.3 shows a typical time versus consistency graph for a permafrost-sealant test composition. The low initial Be ensures a low yield stress and pumping viscosity. The increase in Be is gradual, indicating slow dissolution of MgO and wollastonite in the solution. As the Be increases, its rise to 70 is rapid, and the time versus Be curve is almost vertical. Such behavior ensures that the slurry, once placed, will set rapidly. 

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