Module 4- Gas Compression Operation

Question 1

If you observed a high temperature discharge on a compressor, what 4 possible causes would there be?

Answer 1

1. Aerial cooler problem
2. Inadequate lubrication
3. High Engine Speed
4. Worn, broken or dirty valves

Question 2

If you observed a high second stage suction temperature, what would the 3 possible causes be?

Answer 2

1. Aerial cooler problem
2. High intercooler pressure
3. High discharge pressure

Question 3

If you observed high oil temperature on a compressor, what would the 5 possible causes be?

Answer 3

1. Low coolant injection
2. Dirty water jackets
3. Aerial cooler problem
4. Incorrect oil for application
5. High discharge temperature

Question 4

If you observed low discharge pressure on a compressor what would the 5 possible causes be?

Answer 4

1. Low suction pressure
2. System leakage
3. Low engine speed
4. Worn piston rings
5. Low receipt point pressure

Question 5

If you observed high discharge pressure on compressor, what would the 3 possible causes be?

Answer 5

1. Restrictions in gas processing unit
2. High line pressure at receipt point
3. High engine speed

Question 6

If you observed a high oil consumption on a compressor, what would the 3 possible causes be?

Answer 6

1. oil leaks at gaskets, seals or fittings
2. High oil circulation rate
3. Oil level too high

Question 7

If you observed vibration on a compressor, what would the 5 possible causes be?

Answer 7

1. Loose or damaged mountings
2. Loose or damaged pipe supports
3. incorrect engine speed
4. high discharge pressure
5. couplings misalignments

Question 8

In oilfields operations, how much is gas compressed? what result does that have on temperature?

Answer 8

Gas is often compressed to one-tenth of its origin volume.

This results in corresponding increase in temperature.

Question 9

What does the ideal gas law state about gas reduction and temperature?

Answer 9

Reduction in volume of a given mass = increase in the temperature of the gas.

Question 10

How is heat generation from compression controlled in the oilfield?

Answer 10

compression and cooling between stages

Question 11

what kind of compression enables more efficient cooling between stages?

Answer 11

multistage

Question 12

why is after cooling done?

Answer 12

to reduce the gas volume shrinkage caused by cooling in the transmission lines, thus increasing efficiency of the transmission pipeline.

Question 13

What are aerial coolers designed for?

Answer 13

to reject a tremendous amount of heat from the gas in a very short time.

Question 14

What is gas from a final compression stage passed through before it is passed through the sales meters and onto transmission companies?

Answer 14

aerial coolers

Question 15

What happens as the compressor pistons move forward to compress gas?

Answer 15

differential pressure acting on the piston results in a gas force pushing against the piston, and causing a compressional force on the piston rod.

Question 16

What happens as the compressor move forward to compress gas in a double acting piston?

Answer 16

the compressional force is balanced by the suction action of the back end of the piston as it draws gas in to be compressed.

Question 17

Where is the piston when the maximum compression force occurs?

Answer 17

at its maximum forward travel just before the gas discharge from the top end of the piston.

Question 18

How are reciprocating compressors usually rated?

Answer 18

In terms of horsepower, speed and road load.

Question 19

Define gas loads/inertial forces?

Answer 19

The forces that act simultaneously on a reciprocating compressor during one revolution of the crankshaft include piston rods loads, connecting road loads, crosshead pin loads, crank pin loads, and the frame load.

Question 20

What is volumetric efficiency?

Answer 20

the actual pumping capacity of the cylinder compared to the piston displacement of swept volume.