What gas does RG represent in the process flow diagram?

That should be a radioactive gas; be careful around it

You can take a look at how the design firm defines it; you can check the image on the homepage or call for inquiries.

The element RG is radioactive, but here it probably refers to return gas; think of it as exhaust gas. This can generally be seen on process diagrams

RG stands for rich gas: Rich gas corresponds to lean gas (LG). Based on the hydrocarbon components in natural gas, it can be classified into dry gas and wet gas, as well as lean gas and rich gas. For natural gas obtained from the wellhead of gas wells or separated by separators in oil and gas fields, the classification method is as follows: (1) Dry gas: Natural gas in which, per cubic meter, the amount of hydrocarbons with a molecular weight of C5 or higher is less than 10 mL in liquid form ； 　　(2) Moisture: Natural gas in which, per cubic meter of gas, the amount of hydrocarbons with a molecular weight of C5 or higher is greater than 10 mL in liquid form ； 　　 (3) Lean gas: Natural gas in which, per cubic meter of gas, the amount of hydrocarbons with a carbon count of 3 or more (C3) is less than 100 mL in liquid form ； 　　(4) Rich gas: Natural gas in which, per cubic meter, the volume of hydrocarbons with a carbon count of 3 or more (C3) in liquid form is greater than 100 mL ；

I agree with what was said above; it should be a rich gas, and I don’t think it’s a radioactive gas. However, there is an explanation on the first page of the process flow diagram

Check if it’s on your pID homepage image There should be.