Thermodynamic assessment and proposal of new configurations of an indirect water bath heater for a City Gate Station (a case study)

This paper deals with thermodynamic modeling and proposal new configurations of an indirect water bath heater used in a city gate station (CGS) to preheat the natural gas (NG). In the transmission pipeline of natural gas before reducing NG pressure, it is necessary preheating to prevent hydrate formation. In the traditional systems, an indirect water bath heater is used for this purpose. Thermodynamic modeling of the proposed systems has been done in EES software, and an effective analysis based on proposed new configurations is conducted. The results indicate that using exhaust combustion products to preheat the combustion air can increase the thermal efficiency of the system from ۴۶.۳۶% (for base case) to ۷۳.۸۴%. In addition, with the use of an ORC to utilize the exhaust waste thermal energy, the system efficiency of ۵۵.۲۷% with an electrical output of ۷۹ kW can be achieved. A comparison between configurations indicates that the second configuration (preheating combustion air) with ۷۸.۹۷ kg/h has the lowest emission rate.

Keywords:

Indirect Water Bath Heater , Energy Efficiency , Excess Air , combustion