Recently, a customer with operations in the Eagle Ford was experiencing erratic temperature swings in their triethylene glycol (TEG) reboiler. The producer was trying to maintain a temperature of 390 Farehnhiet (199 Celsius).
Glycol dehydration is a method of removing water from natural gas. Gas containing water—often referred to as “wet gas”—can cause a variety of problems for downstream processes, measurement, and equipment. A glycol dehydration system typically consists of a drums, pumps, condensers, tanks, and a reboiler. The design is to heat wet glycol in order to boil out the water. Furthermore, the reboiler is a critical component of this system.
A reboiler has a fire tube inside. A burner valve controls this. The burner valve receives a signal from the burner management system (BMS). As a result, it sends the appropriate amount of gas into the fire tube. This is done in order to maintain a desired temperature.
Temperature in a glycol reboiler is critical. This is because the fluid inside needs to stay hot enough to remove the water vapor. Yet, it must stay cool enough that it does not cause the glycol to decompose. The burner valve this producer was using appeared unable to hold a steady temperature. Also, their vessel temperature gauge was bouncing between 375 and 395 F (191-202 C).
After discussing the issue with one of our Kimray representatives, the producer installed a Kimray E-LO Control Valve. They connected it to their BMS to address the problem. The E-LO is an electric low-pressure valve that uses a 4-20mA signal to open, close, or throttle.
As shown by the chart above, after installing the E-LO there was a dramatic leveling off of the temperature in the reboiler. Said the South Texas producer, “We were able to install the valve with basically no modification to the piping. The big drop is where it was installed, so there is a pretty significant leveling off on temperature swing with the Kimray E-LO in place.”