Compressor Basics and Multi-Stage Systems

Study Notes

Compressor Basics

A compressor is a mechanical device that increases the pressure and reduces the volume of vapor, moving it through piping or for storage.
Similar to pumps, compressors are designed for vapors and come in centrifugal and positive displacement types.

Multi-Stage Compressors

Multi-stage compressors use two or more compressor stages on a single driver shaft to achieve higher pressure outputs.
Suction gas enters the first stage, is compressed, and then sent to a knockout (KO) drum to remove any liquid before entering the next stage.

C-120A/B (Charge Gas Compressors)

C-120A/B are Dresser-Rand horizontally opposed compressors operating at 325 rpm and 2500 hp, designed for multi-stage positive displacement.
Both compressors typically run in parallel for normal operations.

Suction/Discharge Bottles

Also known as pulsation dampeners, these devices mitigate pressure pulsations during compression cycles to prevent compressor overloading and vibration issues.
Equipped with pulsation dampeners before and after each cylinder in C-120A/B compressors for smoother operation.
Specially designed bottles allow for one-way gas flow resembling check valves, enhancing operational efficiency.
Monitoring valves' temperatures is crucial; high temperatures may indicate valve failures or leaks.

E-120A/B (Charge Gas Interstage Coolers)

E-120A/B are multi-tube U-type exchangers that cool ethylene on the shell side using cooling water on the tube side, installed between the first and second stages of the compressor.
Their primary function is to remove heat generated during compression.

D-120A/B (Charge Gas Interstage K.O. Drums)

D-120A/B are 4’D x 8’2”L vessels equipped with internal demister pads to separate entrained liquid from ethylene after cooling.
Ethylene enters the drum from the side, with liquids exiting at the bottom and vapor exiting from the top.

Description

Explore the essential concepts of compressors, including their functions, types, and designs. This quiz covers both single-stage and multi-stage compressors, with a focus on specific models like the C-120A/B. Gain insights into suction/discharge bottles and their roles in maintaining pressure stability during operation.