May 2013

Special Report: Maintenance/Reliability

Prevent methane hydrate formation in natural gas valves

The discussion here focuses on the thermodynamics involved and on the requirements for a successful natural gas valve application in which the incidences of hydrate formation and icing of the valve are reduced.

Glaun, A., Shahda, J., GE Oil & Gas

Gas flow across a control valve is considered a classic “throttling” process that is defined by energy not being added or extracted from the process gas as it traverses the valve. Therefore, total enthalpy is preserved, entropy increases and the process is thermodynamically irreversible. The consequences of this process are that many real gases experience a drop in temperature while following the constant enthalpy line as the pressure drops across the valve. This effect was first described by William Thomson and James Joule, and it now bears their names. The Joule-Thomson effect is leveraged in the production of cryogenic fluids such as liquid oxygen, nitrogen and argon, and it is

Log in to view this article.

Not Yet A Subscriber? Here are Your Options.

1) Start a FREE TRIAL SUBSCRIPTION and gain access to all articles in the current issue of Hydrocarbon Processing magazine.

2) SUBSCRIBE to Hydrocarbon Processing magazine in print or digital format and gain ACCESS to the current issue as well as to 3 articles from the HP archives per month. $409 for an annual subscription*.

3) Start a FULL ACCESS PLAN SUBSCRIPTION and regain ACCESS to this article, the current issue, all past issues in the HP Archive, the HP Process Handbooks, HP Market Data, and more. $1,995 for an annual subscription.  For information about group rates or multi-year terms, contact J'Nette Davis-Nichols at or +1 713.520.4426*.

*Access will be granted the next business day.

Related Articles

From the Archive



{{ error }}
{{ comment.comment.Name }} • {{ comment.timeAgo }}
{{ comment.comment.Text }}