Written on June 1, 2008 at 5:33 pm, by Dr. Mahmood Moshfeghian
As gas moves through a pipeline its pressure and temperature change due to the frictional loss, elevation change, acceleration, Joule-Thompson effect, and heat transfer from the surroundings. Due to pressure and temperature change, liquid and solid (hydrate) may also form in the line which in turn affects the pressure profile. Modeling and simulation of multiphaseContinue Reading
Written on May 1, 2008 at 5:14 pm, by Dr. Mahmood Moshfeghian
In this Tip of the Month (TOTM), we will continue our discussion on the performance of mechanical refrigeration systems employing propane as the working fluid. Specifically, we will study the effect of the flash tank and heat exchanger (HEX) economizers on the compressor power, the refrigerant circulation rate, and the condenser duty. The details ofContinue Reading
Written on March 1, 2008 at 5:07 pm, by Dr. Mahmood Moshfeghian
In this Tip of the Month (TOTM), we will continue our discussion of the effect of working fluid impurities on the performance of refrigeration systems employing propane as the working fluid. Specifically, we will study the effect on the compressor power, the refrigerant circulation rate, and the condenser duty. In the previous TOTM, the chillerContinue Reading
Written on February 1, 2008 at 4:42 pm, by Dr. Mahmood Moshfeghian
In this Tip of the Month (TOTM), we will demonstrate the effect of working fluid impurities on the performance of a simple propane refrigeration system and another one employing a flash economizer. Specifically, we will study the effect on the compressor power, the refrigerant circulation rate, and the condenser duty. The objective of a refrigerationContinue Reading
Written on January 1, 2008 at 4:29 pm, by Dr. Mahmood Moshfeghian
In this Tip of the Month, we will compare the performance of a simple refrigeration system with another one employing a flash economizer. Specifically, we will evaluate compressor power saving, the effects of compressor suction–line pressure drop and the interstage pressure drop on compressor power requirement and condenser duty. The objective of a refrigeration systemContinue Reading
Written on December 1, 2007 at 10:51 pm, by Dr. Mahmood Moshfeghian
In the last Tips of the Month, we discussed the phase behavior of water-sweet natural gas and water-sour natural gas mixtures. In this tip, we will demonstrate the acid gas–water phase behavior. The water content of a gas depends on the system temperature, pressure and composition of the gas. The phase equilibria in the system H2SContinue Reading
Written on November 1, 2007 at 10:38 pm, by Dr. Mahmood Moshfeghian
In the last Tip of the Month, we discussed the phase behavior of water-sweet natural gas mixtures. In this tip, we will demonstrate the water-sour natural gas phase behavior. In a future tip, we will address water content of acid gases. Water is produced with oil and gas. A question that comes to mind is: “WhyContinue Reading
Written on October 1, 2007 at 10:31 pm, by Dr. Mahmood Moshfeghian
In the past Tips of the Month, we discussed the phase behavior of water-free natural gas mixtures. In this tip, we will demonstrate the water-sweet natural gas phase behavior. In future tip, we will address wet sour gas. Water is produced with oil and gas. A question that comes to mind is: “why water isContinue Reading
Written on September 1, 2007 at 10:27 pm, by Dr. Mahmood Moshfeghian
Many facility operating problems are related to improperly designed or under-sized gas-liquid separators. Due to the importance of separators, in the July Tip of the Month (TOTM), we studied the effect of liquid carry over in a simple dew point control plant. In that study, assuming variable area of the heat exchangers, we found thatContinue Reading
Written on July 1, 2007 at 10:12 pm, by Dr. Mahmood Moshfeghian
Problems in meeting sales-gas dew point specifications are not unusual. A facility engineer often suspects separator carryover when trouble-shooting such a plant. Proper sizing of equipment for vapor-liquid separation is essential to almost all processes. The fundamentals of a simple separator design may be extended to several other processes such as fractionation towers, two-phase flow,Continue Reading
