Thursday, September 8, 2016

Twin Screw Pumps In Multiphase Pumping Technologies

By Laura Smith

A technology that is used in transferring fluids like slurries, liquids, or gases is called a pump. This has three major groups namely the direct lift, the displacement, and the gravity pumps. The one that moves fluid by trapping the fixed amount of fluid and displacing it in the discharge pipe is called the positive displacement.

Gravity pumps are also called as hydraulic rams. These are used by taking water from the underground to higher areas in lower elevations. Multiphase pumping technologies have types and features which includes helicoaxial, twin screw pumps, progressive cavity, electric submersible, and buffer tanks. The advantages of multiphase production are simpler and smaller installation, lesser equipment cost, and increase in production rates.

Centrifugal is another term for helicoaxial. This works by the conversion of rotational kinetic energy to hydrodynamic energy to transport fluids. Rotational energy is coming from the electric motor. The fluid enters the impeller near its rotating axis, and impeller will be accelerating it towards the exit.

A twin screw have two intermeshing screws which will force the fluid movement that is pumped. High volume of gases and fluctuation of the inlet conditions are two types of pumping conditions which are commonly used. To seal these two shafts, four mechanical seals are required.

Progressive cavity is one type of the positive displacement. Sequence progress of small, fixed shape, discrete cavities is used in this type while the rotor is turned. This also acts as motor or mud motor if the solution is being pumped through the interior. Well drilling can be one good application for this.

An electric submersible contains a hermetically sealed motor which is close coupled to the pump. The construction is submerged to the solution that is being pushed. One main advantage of using this is it prevents cavitation, which is a problem about the difference of pump and fluid surface. Submersibles are more efficient than jets, since it pushes liquids to the surface, while jets pulls liquids.

A buffer tank Cobourg ON is installed in the upstream of the suction nozzle in case of slug flows. This breaks the energy of liquid slugs, smoothens fluctuations in incoming flows, and act as sand traps. Pumps are mostly rated in its horsepower, outlet pressure of its head, inlet suction of its head, and flow rate. The head is simplified as the number of meters or feet that the pump raises or lowers the column of water of atmospheric pressure.

Materials that can be used in a pump includes stainless steel, cast iron, and some more. The material will depend on the application of the pump. For pharma application in water industries, stainless steel is commonly used because high temperature of stainless steel can give better result.

Because of the name, multiphase, it involves many variations of its conditions and services which includes changing processes of liquid composition, operation of high and low pressures, temperature variations, and abrasive or erosive media exposure. And the challenge now is selecting the suitable arrangement of support system and mechanical seals in order to know its effectiveness.

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