HPRT

[dhdsvr]

Request to provide experiences of using hydraulic pressure recovery turbines in refineries.

Vendors/suppliers/designers of HPRT is also required.

Thank you

 

[JJPellin]

We have a number of hydraulic recovery turbines in our refinery. They are all Flowserve machines, though some were originally nameplated as Ingersoll-Rand, Pacific or Byron Jackson. Most of them run very well. The main problem we have are mechanical seals. The seal support systems for a recovery turbine should be very different from a pump. If you let your seal supplier put an API plan 11 or 21 set up the same way as it would be on a pump, you will likely have problems. Most of our RT's are on the outlet of a hydrotreater reactor. Some are Naphtha, some are fuel oil. We also have two on the outlet amine stream from an amine contactor. In all cases, the fluid is saturated with gas. If you drop pressure across an orifice for a plan 11 or 21, gas will flash out of solution and you will gas up the seal. We have had better luck with dead-ended primary seals or unusual plans. In one machine, there is a flush line from the inboard seal to the outboard with no other interconnections. This actually works quite well. If you can get the seals to last, a Recovery Turbine is a machine that prints money. The horsepower savings can be very great relative to the installed cost.

 

[checman]

I agree with JJPellin. A couple things you might want to look at to extend your seal life. On the API 11 if the fluid is clean and the pump and seal design allow, use a close clearance throttle bushing made of VESPEL or PEEK to control the flush rate rather than the orifice. You will take the pressure drop after the seal so any degassing will happen after the seal. The higher box pressure will also lower the chance of flashing at the seal faces. On the plan 21 you can do the same or put the cooler before the orifice. In most cases the cooler fluid is less likely to degas or flash. A variation of ANSI plan 14 might be what you need to get good seal life. Remember that gasses are extremely difficult to expel from a seal area. The peripheral shaft speed tends to centrifuge gasses towards the shaft or seal faces.

Regards checman