Draining Oil from Receiver

[R717Kid]

My two cents worth....

In regards to most plants not being able to run lower head pressures, for whatever reason....during a recent project I was able to lower head pressure through system optimization. In the upper midwest I can run 110 psig on a 70 degree night with 60% relative humidity. Winter I can run 95 psig with fans only. In addition, lower head pressure does increase velocity of the gas through the system and it is the older compressors in need of servicing or oil seperators that need help that lend way to oil carryover. Recording everything while making systematic changes is paramount. Motor amperage at the compressors will be very notable when reducing head pressure. Knowing how much oil you are putting into and blowing through a compressor should be part of condition based monitoring. If you are troubleshooing without all the data, then you are playing a guessing game essentially.

Now, if you have operators proping self closing valves open or other bad habbits then you have operators deviating from safe work practices/procedures followed by management who doesn't hold people accountable for these actions and this is how ammonia gets a bad name and accidents happen.

[Segei]

My two cents worth....

In regards to most plants not being able to run lower head pressures, for whatever reason....during a recent project I was able to lower head pressure through system optimization. In the upper midwest I can run 110 psig on a 70 degree night with 60% relative humidity. Winter I can run 95 psig with fans only. In addition, lower head pressure does increase velocity of the gas through the system and it is the older compressors in need of servicing or oil seperators that need help that lend way to oil carryover. Recording everything while making systematic changes is paramount. Motor amperage at the compressors will be very notable when reducing head pressure. Knowing how much oil you are putting into and blowing through a compressor should be part of condition based monitoring. If you are troubleshooing without all the data, then you are playing a guessing game essentially.

Now, if you have operators proping self closing valves open or other bad habbits then you have operators deviating from safe work practices/procedures followed by management who doesn't hold people accountable for these actions and this is how ammonia gets a bad name and accidents happen.

You are focused on lowering head pressure. This approach will always save energy for the compressors , but not always for the system(plant). Sometimes reduction of head pressure from 120 psig to 110 psig will save you 20 HP of compressor power, but this step require additional 30 HP of condenser power. It means that plant is more efficient at 120 psig. During summer operation to minimize energy use condensing pressure should "float" up and down based on wet bulb temperature.
Oil carry over is a barrier to operate plant at low condensing pressure, but every barrier has a solution.