Archive for October, 2012

Shell-and-Tube Heat Exchanger Selections

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There are three basic types of shell-and-tube heat exchangers: fixed tube sheet, floating head, and U-tube. The list below summarizes the comparison between these three exchangers. Fixed Tube Heat Exchanger Advantages 1. Low cost 2. Fewer gaskets. 3. Individual tubes are replaceable. Disadvantages 1. The shell can not be clean or inspect. 2. Limited temperature …

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Parallel Plate Interceptor Design Diagram

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Parallel Plate Interceptor Design Diagram

The parallel plate interceptor (PPI) is the early form of a plate coalescer. The basic design of parallel plate interceptor is a series of plates installed parallel to the longitudinal axis of an API separator as shown in figure above. The plates form a “V” shape so that the oil sheet moves up the underside …

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Dispersed Gas Units Separator

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Dispersed Gas Units Separator

A vortex set is used to disperse gas bubbles in the stream on dispersed gas units. The figure above shows a dispersed gas units with hydraulic eductor schematic. Clean water from the effluent is pumped to a recirculation header (E) that feeds a series of venturo eductors (B). Water flowing through the eductor sucks gas …

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SP Pack Separator

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SP Pack Separator

The SP Pack separator is developed by Paragon Engineering Services, this separator creates turbulent flow by forcing the water to flow through a serpentine pipe path. The path is correctly size to create a correct turbulence to cause coalescence but not great enough to shear the droplets. The pipe path will not cause a plugging …

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Dissolved Gas Flotation Unit

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Dissolved Gas Flotation Unit

Dissolved gas unit allows the water and gas saturation in a contactor. A typical Dissolved gas unit works on 20 to 40 psig contact pressure, more gas can be saturated in higher pressure. The water is taken from the treated water; the gas saturated water is then injected into the floatation tank. The dissolved gas …

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Corrugated Plate Interceptor Design

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Corrugated Plate Interceptor Design

Corrugated plate interceptor (CPI) is the most common parallel plate interceptor in oil facilities. CPI is an improvement of the PPI, CPI take less area for the same particle size removal. The figure above shows down flow CPI diagram. The parallel plates in CPI are corrugated parallel to the flow direction. The plate pack is …

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Increasing Retention Time to Create Larger Water Droplet

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A small increase in water droplet diameter will increase the settling rate since water droplet is squared in the settling equation. The water droplet size will increase within a retention time in the coalescing section, adding a heat input will speedup the process since heat will excites the collisions of small droplet to create larger …

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Gravity Separation Velocity Calculation

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Gravity Separation Velocity Calculation

The gravity force is commonly used in oil treating equipment to separate the water from the oil in continues phase; the water droplet tends to separate from the oil since it’s heavier than the oil. The separation speed is limited by the drag force caused by the water movement through the oil; the constant velocity …

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Plate Coalescers to Improve Gravity Separation

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Plate Coalescers to Improve Gravity Separation

We can use plate coalescers to improve gravity separation process, a plate coalescers can be formed as internal plates on skim tanks or vessels. The plate coalescers configurations are: parallel plate interceptors (PPI), corrugated plate interceptors (CPI), or cross-flow separators. All of these configurations depend on gravity separation. When coalescence occurs, the oil droplets will …

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Foamy Crude in Production Separator

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The non-water substance appearance in crude is the major cause of foam in crude problems. Those substances will not be removed until the crude enters the separator. The separator must be designed properly to have adequate time or coalescing surface to break the foam. Three major problem of foaming crude in separator is as follow: …

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