## Pressure Drop the Cost Implications for Separation

As in solid-liquid hydrocyclones, pressure drop Ap & Qm where 2.1 <m <2.2. In dimensionless terms defining:

Euler Number NEu =

Ap i pu2

Reynolds Number NRe =--

v where uf = Qf/Ai and the inlet port diameter = Di (for multiple or noncircular inlets Di is the diameter of the circular port with equal Ai).

Leads to the dimensionless relationship where

The use of uf in terms of Qf and Ai will be reflected by changes in the swirl number S.

Values of p and v are based on arithmetic averages of the mixed liquids. Uncertainty in the value of the kinematic viscosity v is not serious due to the small value of n. Typical Euler Number values are in the range 10-20 and do not seem to be affected by variations in Cf.

The de-oiling hydrocyclones have a substantial pressure gradient along the hydrocyclone axis not present in solid-liquid hydrocyclones with an air core. Thus pressure drop between the feed and the overflow Apfo is greater than the pressure drop between the feed and the underflow Apfu, the relationship between the two being variable and set by external valves. The ratio between the two is important for control and optimization and this pressure drop ratio (PDR = Apfo/Apfa) varies with split ratio, Rf and also its complement F. Apfo has two principal components - one due to the radial pressure gradient and the other arising from the velocity through the overflow port. The radial pressure gradient and Apfu are both proportional to the u2 and S, since uf = Qf/Ai. For a fixed geometry the PDR = B1 + B2 x F2 where B1 and B2 are constants, where B1 = /1(S) and B2 = f2 (S, AT1). The oil concentrated overflow rate is regulated by using a fixed PDR value as set-point.

Pumped installations In younger oilfields the driving pressure stems from reservoir pressure. In older fields where pumping is necessary, this represents a cost. To reduce droplet break-up a low shear positive displacement pump should be used, however centrifugal pumps have proved satisfactory provided their speed is not too high and the duty is not too far from their best efficiency point. Fields with electrical submersible pumps have utilized de-oiling hydrocyclones satisfactorily.

## Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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