The industry standard for water concentrations in natural gas is less than 7 pounds per MMSCF. Concentrations above this amount will risk formation of line-blocking, gas hydrates (ice formations that encapsulate gas molecules) within the pipe when line pressure drops or pipe temperature approaches freezing. A preferred method of combating hydrate formation is to reduce the dew point of the gas by adding methanol to the flowing gas. On-the-fly ratio control is set by monitoring the gas flow, computing the proper dosage of methanol, and recording the occurrence and quantity of injections. Changes in gas temperature and pressure affect the dosage flow enough that closed loop control is required to maintain the desired dehydration level under all operating conditions.
Desired dosage amounts are achieved through varying stroke count and rate on an injection pump system. The intermittent flow of methanol is only measurable with positive displacement meters which are accurate despite the start/stop flow profile. To accurately sum the small injected amounts, a high resolution meter with hundreds of pulses per cc is needed to not miss a drop and provide quick, repeatable verification of the flow.
Max equipment specified:
The Model P213 is used to accurately measure instantaneous injection rates from 1 - 1500 cc/minute. For instantaneous rates above 1500 cc/minute the Model P214 is the recommended meter. A high resolution transmitter (1000 pulses/cc – Model P213) is required because of the low flow and sudden on-off conditions associated with odorant injection pumps. If you would like a quote for a similar project, please let us know.
You all at Max Machinery are one of the most pleasurable principals to work with from my standpoint. Informative, responsive, helpful and always striving to go the extra mile. It really is appreciated - P. Lawrence, Avensys Solutions