Phymetrix portable moisture analyzer model PPMa shown in use at a natural gas cryogenic fractionator. The PPMa is hooked up after the mole sieve dryer after the methanol injection, just before the fractionating cryogenic separator. The PPMa is setup to log overnight the moisture content of the gas in order to evaluate the capacity and column switching times of the mole sieve dryer. Keeping the moisture content low has many benefits including a lessening need for thawing out the cryogenic separator to remove the accumulated ice.
The ability of the PPMa to operate in a wide temperature range and its impact resistant IP 65 weatherproof housing allows it to be used even in the toughest environments such as this Colorado winter snow storm overnight logging. The sensing technology’s insensitivity to methanol is also a unique and important factor in this measurement.
The data shows that the mole sieve dryer is undersized and the columns are not switched often enough. The breakthrough of moisture that occurs about 6 or 7 hours into the cycle adds undesirable quantities of moisture. It shows engineers that they need to switch the columns more often and regenerate the mole sieve better by increasing regeneration cycle temperature and/or flow.
No other portable analyzer can be used in this kind of rough environment. However the PPMa not only operates but makes accurate and fast measurements that other analyzers can not perform. Most other analyzers experience interference from the methanol being injected into the gas stream.