D2L quiz questions Flashcards
The amount of moisture contained in an air volume compared to the maximum amount that it could hold at saturation is known as:
Relative Humidity
What is the primary purpose of a coalescing filter?
To remove oil from air flow.
Reactivation of liquid dehydration dryers is accomplished by:
Heating the glycol in a still.
What dryer provides the lowest dew point?
Desiccant dryer
also know as Adsorption Dryer, dew point as low as -70C
Desiccant dryers are also known as:
Adsorption Dryers
What are dryer pre-filters used to trap?
Solid contaminants and Oil
The air leaving the evaporator in a refrigeration dryer has a dew point of 2 degrees C. What is the dew point after it leaves the air to air exchanger and exits the dryer?
Equal to 2 degrees C
Absorption type dryers use a chemical bond between the drying agent and the gas stream. What absorption dryers use a consumable deliquescent?
Chemical Dryers
What is the name for the temperature at which water vapour will condense to a liquid?
Dewpoint
As air is heated, its ability to hold water vapour will:
Increase
What desiccant is commonly used in adsorption dryers?
Activated Alumina
Flow rates which exceed the stated capacity of a dryer will result in:
Poor dew point reduction
After air leaves the aftercooler, any further reduction of temperature will result in:
Condensation
What is installed to prevent oil contamination of the desiccant in an adsorption dryer?
Coalescing pre-filters
What dryer does water vapour adhere to the surface of a desiccant?
Adsorption dryer
The desiccants found in air dryers can be:
Regenerated
How does an increase in the temperature of a given volume of air affect its dew point?
It is unaffected
What sequence of heat exchangers does the compressed air flow through in a refrigerated dryer?
Air to air - evaporator - air to air
What dryer uses glycol as a drying agent and has a still for regenerating the glycol?
Liquid Dehydration
In an absorption dryer a deliquescent changes from?
a solid to a liquid(brine)
The limitation of the adsorption dryer is the amount of moisture the media can hold. What is done to overcome this limitation?
Regeneration
What can cause an increased pressure drop across a desiccant dryer:
The desiccant breaking down
Chemical dryers use deliquescent materials that slowly ______ and cannot be _______.
Dissolve, and cannot be Regenerated
What type of dryer is designed to lower the dewpoint to 2 or 3° C?
Refrigerant
Who must install a lock while performing maintenance tasks?
All persons involved in the maintenance.
What method is used to remove liquids and solids from the gas stream upstream of a gas compressor?
Reduction in velocity / change in direction of gas
The four main categories of dryers are:
Mechanical, Refrigeration(cooling), adsorption and absorption.
What are the steps in a heated regeneration desiccant dryer cycle in the correct order?
Drying, regeneration, cooling
A refrigeration dryer has two flow paths. They are:
The compressed air circuit and the refrigerant circuit
On an adsorption MD type dryer, what gas is used for regeneration?
Compressed air from upstream of the aftercooler
Heatless dryers rely on what (%) portion of the dry gas flow being circulated through the bed to be regenerated.
15%
Check __________ differential for an increase indicates time to changed out filters
Pressure differential
Demister pads are used where?
Outlet/exit of process vessels
(Can be found after glycol contractor on liquid dehydration dryer)
