TEG Circulation Rate Calculation
In this blog, we’ll show you how to calculate the amount of triethylene glycol (TEG) you need to run through your dehydration system to meet dew point, and help you size the right glycol pump to circulate the TEG.
Water Content of Natural Gas
The chart below shows the water content of your natural gas at various pressures and temperatures. This is the maximum amount of water you can expect your natural gas production to hold at the given pressures and temperatures.
On the left side of the chart is temperature. On the top is pressure.
So for example, if your gas measures 100 degrees F at 400 PSI, your water content will be 128 pounds of water for every 1 MMCF (million cubic feet) of production.
Moving down to the equation, this means you:
- multiply water content (W = 128)
- by the flow rate (in this example we’ll use 1 MMCFD) (M = 1)
- by gallons of glycol to remove 1 pound of water, which most producers set at 3 (G = 3)
- and then divide by 24 (hours)
You’ll get the “GPH,” which is the Gallons Per Hour of TEG you want to move through your system to dehydrate your gas.
In this example, our TEG circulation rate calculation gives us 16 gallons per hour.
The chart below will show us which glycol pump is capable of that.
Glycol Pump Sizing and Stroke Count
If the goal is to move 16 gallons per hour, we’ll locate that in either the 1720 PV or 4020 PV pump.
Moving up to the row of bold numbers, we can see that in order to move 16 gallons per hour, we need our pump to stroke 16 times per minute.
You adjust your Energy Exchange Glycol Pump by opening and closing the two needle valves (at the same rate) on the pump. This controls the speed at which the glycol is entering the pump, which changes the circulate rate.
To know your stroke count, you’ll need to listen to the the distinct sound on the pump itself and count the strokes. Note that one stroke of the glycol pump is the piston moving one direction (not both there and back).
After 15 seconds, you can multiply your number of strokes by 4 to get the stoke rate per minute.
So for our example, we would need 4 strokes in 15 seconds to equal 16 per minute.
To speak with a regional expert about your gas dehydration system, contact your local Kimray store or authorized distributor.