New energy-saving temperature controller for heater at natural gas gate station

Some stations in the gas transportation system experience a decrease in natural gas (NG) pressure. The drop in pressure occurs in the regulators and causes the temperature to drop so that the gas must be preheated to prevent it from freezing. The present study investigated this phenomenon at Akand City Gate Station, which has a nominal flow rate of 120,000 SCMH. Preheating of the NG in the station regulator was shown to consume excessive fuel to run heater. A new temperature controller was installed where the NG line leaves the second regulator of the station to decrease heater gas consumption. The station was simulated in HYSYS software to calculate the amount of possible decrease in usage. The real temperature of NG stream measured at the second regulator and the results of two state equations to reach minimum deviation were compared. The results showed the new NG temperature controller decreased heater gas consumption more than 431,000 SCM, which resulted in a cost savings of over $43000 annually. It is predicted that the implementation of this controller at all of the more than 50 stations city gate stations belonging to Mazandaran Gas Company will result in significant savings for the company of up to $1 million annually. (C) 2015 Elsevier B.V. All rights reserved.