I posted this question back in January of 2013 but did not get a definitive response. I am trying again.
My question is how to calculate the flow rate of gas only blowthrough through a Hydraulic Power Recovery Turbine (HPRT)
The scenario is upon tripping of the unit feed pump say in a hydrotreater, liquid level in the high pressure separator vessel will be lost and high pressure gas will start to blow through from the high pressure separator vessel to the low pressure separator vessel, located down stream of the HPRT. The relief valve protecting the low pressure side will need to then handle the gas blow through flow.
The question is does the HPRT provide any appreciable resistance against the gas flow and if so how is this resistance accounted for? Or is the resistance to gas flow basically set by the level control valve at the HPRT inlet (choke flow through the valve when the pressure ratio of the high pressure to low pressure side is greater about two) with the HPRT itself not providing a rate limiting resistance to the gas flow?
Thanks
