Natural Gas Engines
 

Natural gas is an abundant clean-burning fuel that provides an important part of the overall energy usage in the United States.  Gas (CH4), also known as methane, undergoes a number of processes as it is transported from wellhead to end-user, and many of these steps require filtration of the product.  Impurities such as pipe scale, iron sulfide, hydrates, water, liquid hydrocarbons, sulfur products and carbon dioxide must be removed before it is deemed “pipeline quality”.

 

Natural Gas Wellhead

 

Natural Gas Well and “Christmas Tree”

 
Gas-fired engine-compressor sets “gather” the natural gas from the wellheads, and pump it to a gas processing plant to make it marketable.
 

The following map shows the network of pipelines that transport natural gas throughout the United States, as monitored by our Federal Energy Regulatory Commission.

 

Natural Gas Pipelines

 

Interstate Gas Pipelines

 

Notice the spider-webs of pipelines in the Gulf area, in western Texas, in the panhandle of Oklahoma and in western Pennsylvania.  Several pipelines come in from Canada.  Most of the gas is pumped to the upper Midwest and industrial sectors of the Northeast.

The natural gas is pumped in large underground pipelines, often 24” to 36” in diameter, at pressures of up to 3000 psig, traveling about 60 feet per second (approximately 40 miles per hour).

 

Natural Gas Pipeline

 

Natural Gas Pipeline & Compressor Station

 

These “compressor stations”, as they are called, are positioned about every 100 miles up the pipeline, to boost pressures and maintain flow.

 
 
 
Natural Gas Filtration Terminology
   
Antifoam chemical additive used in amine plants
Amine a solvent used to strip H2S from natural gas
Blanketing flowing gas and liquid in the same vessel
Break Time how long it takes for foam to return to a liquid
Burping process liquids exiting the top of the  contactor
Carry-Over process liquids exiting the top of the  contactor
Claus Unit a type of de-sulfurization system
Contactor a type of amine
De-Hy a unit to remove H2O from natural gas
DGA a type of amine
Downcomer a pipe going down
Fat amine or glycol saturated with H2S, CO2 or H2O
FERC-636 laws deregulating the gas transmission industry
Flash Tank a drum to separate gas from liquid
Foaming bubble formation in amine & glycol units
Glycol a chemical used to take water out of natural gas
Header a pipe distribution system
Injection pumping gas into an underground storage field
L & R’s pig traps, for launching & receiving pigs & spheres
Laterals pipes running at right angles to the main line
Lean amine or glycol , stripped of H2S, CO2 or H2O
MDA/MDEA amine or glycol , stripped of H2S, CO2 or H2O
Off-Spec Gas  natural gas that is not of pipeline quality
Overhead light-end gases separated in refineries
Pentane Ins. A measure of particulate contamination in oil
Pigging running a rubber barrel through a pipe to clean it
Puking severe foaming, causing unit shut-down
Reboiler steam heat
Reflux a return loop
Rich amine or glycol saturated with H2S, CO2 or H2O
Scrubber a slug-catcher or gas filter
Separator a mist-eliminator, similar to a gas scrubber
Sour Gas natural gas with more than 3% sulfur
Shut-In to block or purge a section of pipeline
Slip-Stream a bypass-filter diverter loop
Still a heater that separates water from glycol
Stripper a liquid-liquid contactor
Sulfides a black iron compound found in sour gas
Sump a collection tank below a gas separator
Tail Gas waste gas from refinery operations
TAN total acid number, measures lube oil degradation
TEG a type of glycol
Two-Phase running both gas & liquid through a vessel
Trays a form of tower packing
Upset severe foaming, causing unit shut-down
Withdrawal pulling gas out of storage