Terminal Velocity

{0 Comments}

Terminal Velocity

Sizing of vessels for separation of liquid phases is based on a theoretical model and equations for terminal or free-settling velocity of a spherical particle in a fluid. As in vapor-liquid separation, the point is to reduce the velocity of the bulk fluid enough to allow entrained droplets to settle. The general equation is: In […]

Read More…

Liquid Surge Volume

{0 Comments}

Unless surge volume has been specified elsewhere, provide liquid volume between the maximum and minimum liquid levels to give the following residence times for each product stream. This is for control purposes: Stream Time, Minutes Distillation Column Reflux 6 Net Product to Storage 4 Net Product to Onplot Column or Heater 10 Net Product to […]

Read More…

Vapor Velocity in Mist Eliminators

{0 Comments}

Vapor Velocity in Mist Eliminators

Mist eliminators, consisting either of knitted wire mesh pads (demisters) or corrugated sheet metal vanes, are often used in critical services to improve separation of entrained liquid. Droplets that are too small to settle strike the wires or the vanes, collecting to form larger drops. The larger drops run down the wires or vanes and […]

Read More…

Mass Velocity

{0 Comments}

Mass Velocity

Entrained liquid droplets must settle out of the vapor stream as the vapor moves upward in a vertical separator or horizontally through the vapor space of a horizontal separator. The designer must keep vapor velocity sufficiently low by providing enough cross-sectional area. The area needed is found by using a correlation of maximum allowable mass […]

Read More…

Selection of Separator Type

{0 Comments}

Selection of Separator Type

Vertical Separators The vertical separator (Figure 300-5) accommodates a tangential inlet, which assists removal of entrained liquid from vapor. Knockout drums which protect compressors are a demanding service, and are usually vertical. The vertical separator takes less plot space than a horizontal separator, is not as susceptible to internal wave action, and is easier to […]

Read More…

Corrosion Inhibitor

{0 Comments}

To clean up amine, the rate of particulate generation must be slowed and the iron sulfide already in the amine filtered out. Reducing corrosion rates is the way to do this. In one Midwestern refinery, the amine solution was thick with iron sulfide. Within two weeks, the solution was restored to a light gray by […]

Read More…

Cleaning Up Amine

{0 Comments}

The iron sulfide particulates circulating in a dirty amine system have built up from a combination of factors. Foremost among these is inadequate filtering. There are three common types of filters: rotary precoat filters, cartridge filters, and stacked paper plates. In practice, paper plates are best. In particu­lar, Sparkler stacked filters are easy to maintain. […]

Read More…

Dirty Amine Ruins Operation

{0 Comments}

Running a sulfur recovery operation with dirty amine is analogous to deficit spending. You are borrowing against the future, but the day of reckon­ing will surely come. The insidious aspect of circulating dirty amine is its erosive nature. Carbon steel is corroded by clean amine. However, the sulfide products of corrosion stick to the metal […]

Read More…

Dirty Amine

{0 Comments}

Symptoms of a dirty, corrosive amine system are: Carry-over of amine from the scrubbers. Dilution of the amine system with water due to reboiler leaks. Plugging of instrument taps with particulates in the amine. Loss of amine to the sewer because of leaks. Rich amine leaking into lean amine in the cross exchanger. Problems related […]

Read More…

Amine regeneration flowsheet

{0 Comments}

Amine regeneration flowsheet

Figure 4-1 is a process flowsheet showing how amine solution is circu­lated to various refinery scrubbers to absorb H2S. The lean amine chemically combines with H2S (and unavoidably some C02) in the scrubbers. The resulting rich amine is stripped in the regenerator. Released acid gases (H2S and C02) are charged to the sulfur recovery plant. […]

Read More…