What type of equipment uses a high-voltage field to break down the stabilizing film surrounding suspended droplets, such as in desalting crude oils?

Correct answer: Electrical coalescers

Explanation

This question tests the knowledge of specialized separation equipment. Electrical coalescers are a specific type of coalescer that use an electric field to destabilize emulsions, a common problem in applications like crude oil desalting.

Other questions

Question 1

In gas separation, what is the term for regenerating an adsorbent by raising its temperature?

Question 2

What is the typical range for the length-to-diameter ratio (Lv/Dv) of a horizontal separator operating at a pressure between 20 and 35 bar?

Question 3

In a vertical gas-liquid separator, a demister pad is not used. By what factor should the settling velocity (ut) obtained from Equation 16.6 be multiplied to provide a margin of safety?

Question 4

What law is used to determine the settling velocity of dispersed phase droplets in the design of a decanter?

Question 5

Which type of evaporator is specifically suitable for use with materials that tend to foul heat transfer surfaces and where crystallization can occur?

Question 6

In a reverse osmosis (RO) plant, the feed water is pressurized to overcome the difference in what potential between the retentate and permeate?

Question 7

What is the term for a membrane separation process where a charged membrane is used to increase the selectivity for a solute, with a close analogy to dialysis in organisms?

Question 8

For a horizontal separator operating at a pressure greater than 35 bar, what is the recommended length-to-diameter ratio?

Question 9

In a four-bed PSA plant designed to purify hydrogen, with an adsorption time of 300 seconds and 85 percent bed loading, what is the calculated mass of adsorbent (Ma) required per bed for a feed rate of 1000 kmol/h?

Question 10

What is the ideal separation factor, or membrane selectivity (Sij), defined as?

Question 11

Which type of membrane module construction involves gluing hollow fibers into a resin to form a closure similar to a tube sheet in a heat exchanger?

Question 12

In a vertical separator designed to separate a mixture of steam and water at 4 bar, what is the calculated settling velocity (ut) if the liquid density is 926.4 kg/m3 and vapor density is 2.16 kg/m3?

Question 13

According to the procedure for designing a decanter, what is the assumed droplet size used to calculate the initial settling velocity?

Question 14

What is the typical minimum liquid hold-up time that would be allowed for in the design of a vertical gas-liquid separator for smooth operation and control?

Question 15

In the design of a decanter, what percentage of the decanter height is usually taken for the dispersion band for design purposes?

Question 16

What type of separation equipment is suitable for difficult liquid-liquid separations where the difference in specific gravity is as low as 100 kg/m3 and can handle high throughputs up to 100 m3/h?

Question 17

For the separation of dissolved solids, which process is described as the removal of a solvent by vaporization from solids that are not volatile?

Question 18

In an evaporator design for concentrating 4000 kg/h of apple juice, with a latent heat of evaporation of 2200 kJ/kg, what is the required heat exchange duty to remove 40 percent of the water content?

Question 19

Which type of crystallizer is considered the most important for large-scale use in the chemical process industry?

Question 20

What is the term for the precipitation technique where a salt like ammonium sulfate is added to an aqueous solution to cause precipitation?

Question 21

In a three-stage reverse osmosis plant designed to produce 50 kg/s of water, what is the calculated overall recovery of water from the feed?

Question 22

An anion exchange resin has a capacity of 1.8 eq/L. If a bed is designed to be 80 percent loaded at the end of a 2-hour cycle where the molar loading is 13.79 kmol, what is the required bed volume?

Question 23

Which form of chromatography is described as being more like an adsorption-desorption process and is the most widely used for recovering biochemicals and large molecules?

Question 24

What type of separation process is probably the most widely used method in gas separation, can be expensive for bulk quantities, but allows for very high purities?

Question 25

A PSA plant has a feed gas at 25 atm and the off-gas is discharged at 2 atm. The methane mole fraction in the off-gas is 0.870. What is the partial pressure of methane in the off-gas?

Question 26

What is the only commercial gas separation process that uses a microporous membrane?

Question 27

A horizontal separator is designed to separate a liquid (density 962.0 kg/m3) from a vapor (density 23.6 kg/m3). What is the calculated settling velocity (ut)?

Question 28

In a decanter separating a light oil (dispersed phase, density 900 kg/m3) from water (continuous phase, density 1000 kg/m3, viscosity 1 mN s/m2) with 150 micrometer droplets, what is the calculated rising velocity (ud) of the oil droplets?

Question 29

Which type of evaporator is specifically grouped with callandria evaporators and is commonly used in the sugar industry?

Question 30

What is the typical range for the osmotic pressure of a NaCl solution at a molality of 2.00 mol/kg at 40 C?

Question 31

In a simple cascade reverse osmosis plant, the first stage permeate has a salt concentration of 0.39 wt percent. The second stage reduces this, resulting in a permeate salt concentration of what value?

Question 32

What is the primary factor that limits the use of hydrocyclones for liquid-liquid separations compared to solid-liquid separations?

Question 33

Which technique is NOT listed as a common method for precipitation?

Question 34

What is the typical regeneration method for activated carbon used in Temperature Swing Adsorption (TSA) for removing trace organics from vent gases?

Question 35

What is the primary mechanism of permeation for a dense (non-porous) membrane used in gas separation?

Question 36

In a horizontal separator operating at 21 bar, with a liquid density of 962.0 kg/m3 and vapor density of 23.6 kg/m3, the hold-up time was found to be 7 minutes, which was unsatisfactory. To achieve a satisfactory 12 minutes, by what factor should the vessel diameter be increased?

Question 38

If a decanter is designed to separate a light oil from water, and the inlet velocity is kept below 1 m/s, what is the calculated pipe diameter for an inlet flow rate of 1.7 x 10^-3 m3/s?

Question 39

What is the primary disadvantage of scraped-surface crystallizers mentioned in the text?

Question 40

A reverse osmosis plant uses 40 m2 membrane modules that achieve a flux of 0.4 m3/m2 per day. If the required flow through a stage is 5114 m3/day, how many modules are needed for that stage?

Question 41

What is the typical amount of regenerant used in an ion exchange system, expressed as a percentage of the stoichiometric equivalent of the exchanged ion?

Question 42

In what type of chromatography is the stationary phase selected to have a pore structure that excludes the desired product, causing it to elute first?

Question 43

What type of separation uses a lead-lag arrangement of two beds in series to allow for complete use of the sorbent and reduce waste disposal costs?

Question 44

What is the primary trade-off in the design of cryogenic distillation processes?

Question 45

When designing a decanter to separate a light oil from water, the final check on the design involves calculating the entrained water droplet size. What is a satisfactory maximum size for these droplets?

Question 46

What is the typical composition of the permeate when an ion exchange process is used for full deionization of water?

Question 47

In a process to remove 1 percent acetylene from ethylene, a catalyst achieves 90 percent acetylene saturation. What separation method is mentioned for this duty?

Question 48

What is the typical hold-up time for a reflux drum in a distillation process?

Question 49

What is the primary purpose of thickening as a separation process?

Question 50

What type of filter is described as the simplest type of batch filter, consisting of a tank with a perforated base?