Product Announcement from Max Machinery, Inc.
Typically, state regulations dictate the minimum odorant concentration. Since these odorants (mercaptan organosulphurs being the most common) are expensive, there are economic concerns regarding excessive dosing.
The odor threshold of mercaptans is approximately one part per billion. Typical mercaptan doses are in the range of 2 - 4 ppm (by volume, to gas); this translates to about 1 - 200 cc/min, depending on pipeline size and natural gas velocity.
Sophisticated flow monitoring equipment is essential to ensure proper dosing; low flow accuracy and repeatability are required as well as easily-integrated (via computer, P.C. and/or telemetry interface) signals.
MAX Equipment Specified: The MAX-213 meter is used when the minimum dosage rate (averaged out on an instantaneous basis) falls below 40 cc/min; the 214 meter is used when the minimum rate is over 40 cc/min or the maximum rate is over 1500 cc/min. Typical applications are either in the 1 - 10 cc/min or in the 50 - 200 cc/min ranges. A solid state transmitter is required because of low flow and sudden on-off conditions usually associated with mercaptan injections (since plunger-type pumps typically are used, intermittent and/or pulsating flow rates are the rule).
Max meters are the industry standard for city gate sites. Please consult your injection pump manufacturer or Max Machinery to add precision to your system.