Dryers

Question 1

Relative Humidity

Answer 1

• the comparison of the amount of water a sample of air holds to the maximum amount it could hold if saturated (think %)
• the higher the temperature the lower the relative humidity because hotter air can hold more water

Question 2

Dew point

Answer 2

• the temperature to which a gas must be reduced before the water vapour it carries begins to condense
• affected by both temperature and pressure. Increasing temperature doesn’t increase the dew point but increases the gap between when you will reach the dew point, increasing pressure decreases the dew point

Question 3

Dew point depression

Answer 3

-lowering the dew point

Question 4

Types of dryers

Answer 4

• adsorption (physical)
• absorption (chemical)
• refrigeration
• mechanical

Question 5

4 Types of desiccant

Answer 5

• activated alumina
• granulated silica gel
• bead type modified silica gel
• molecular sieves (acts as a filter and restricts the size of molecules that are allowed to pass-used with hydrocarbons, nitrogen, hydrogen)

Question 6

Regeneration for heatless

Answer 6

-uses 10-15% of regenerated pressure

Question 7

What measures if your desiccant is full or breaking down?

Answer 7

-hydrometer

Question 8

Two types of Absorption dryers

Answer 8

• chemical (uses Deliquescents and can’t be regenerated)

- liquid dehydration (uses glycol and the glycol can be regenerated)

Question 9

Deliquescents

Answer 9

• calcium chloride, salts or urea

- dissolve as they combine with the moisture they are absorbing

Question 10

Liquid Dehydration Dryer

Answer 10

• the glycol can be regenerated at 98%

- can lower the dew point of a gas by 40-60 degrees from when it enters the dryer

Question 11

Latent heat

Answer 11

• heat required to create a change of state like ice to water, water to steam
• uses more heat energy because it requires additional heat to keep changing the state after it reaches the boiling state.

Question 12

Sensible heat

Answer 12

• heat you can measure as its changin

- until it reaches its boiling point

Question 13

Coalescing filters

Answer 13

• remove oil and water in the form of aerosols too small to be captured by regular filters before they can get to the desiccant bed
• Used pre filters before the inlet as well as downstream

Question 14

Rotary drum (MD)

Answer 14

-25% of the desiccant pad is regenerated at the same time as the 75% of the air is dried.

Question 15

Refrigeration Dryer

Answer 15

-least expensive method of dew point depression.

Question 16

Mechanical Dryers

Answer 16

• liquid separators (least complicated)
• Centrifugal separators (after an after cooler)
• demister pads
• over compression (only mechanical method that can lower the dew point)
• coalescing filters

Question 17

Liquid separator

Answer 17

-least complicated of the mechanical

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Question 18

Centrifugal Separator

Answer 18

-

Question 19

Demister Pads

Answer 19

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