Energy Recovery Turbines (ERT)
Energy Recovery Turbines (ERT)
(OP)
Anyone have experience with the electrical operation of operating these in parallel to serve pumps. The turbines are about 2000kw each and the pumps they will operate are at 1500HP each.
I assume the turbines will operate similar to disel engine generators in parallel.
Thanks.
I assume the turbines will operate similar to disel engine generators in parallel.
Thanks.






RE: Energy Recovery Turbines (ERT)
RE: Energy Recovery Turbines (ERT)
RE: Energy Recovery Turbines (ERT)
RE: Energy Recovery Turbines (ERT)
1. Is this an existing or planned (non-existing) installation?
2. What are the ratings of the hydro units /voltage/excitation type/ turbine type/ governors or not/head/ flow...
3. Parallel with a utility or islanded?
4. Pumps: Horizontal, started DOL with pump dewatered, or what..
It would seem unlikely that you could start such large pumps DOL with such small hydro units unless paralled with a utility source. You said VFD. Maybe you meant soft start.
It would seem that this is something in the planning stage.
Others invited to comment here.
regards, rasevskii
RE: Energy Recovery Turbines (ERT)
Basically it is a type of energy conservation method similar to wind turbines.
High Pressure Recovery Turbines (HPRT) are very common in petrochemical industry where a large induction motor is in between a pump and a turbine.At the start,the ind motor is driving the pump.After sometime, when the plant is settled there is a liquid head freely available through the turbine and by using a clutch arrangement now the motor is coupled to the turbine at a certain speed which is above the syn speed.As a result,now the induction motor is running as a simple induction generator thereby transferring active power (MW) to the network.
Unfortunately I donot have actual numbers with me at this momement.
RE: Energy Recovery Turbines (ERT)
Is this really a stand alone, islanded system? Or is it connected to the utility grid?
As others stated, there will be problems running a 1500 HP motor on a VFD with a 2 MW turbine. The harmonic currents alone will create issues with the generator unless the unit is a special design to handle the extra heating.
RE: Energy Recovery Turbines (ERT)
I am not understanding why the ERTs need to be connected to the grid to operate.
Good point about harmonics from VFDs
RE: Energy Recovery Turbines (ERT)
RE: Energy Recovery Turbines (ERT)
To help we need more information about the existing setup, and what you intend to do or add onto the existing. Is there a tie with the utility or not... What kind of plant is this..for example a paper mill..in an isolated location with a weak tie to a grid?
There are many VFD and soft start experts on this forum available, I am not one of them, but they are waiting as ever for more adventures...
regards, rasevskii
RE: Energy Recovery Turbines (ERT)
An undersized diesel generator may often start a motor that rules of thumb and sizing programs say that it can't.
If the turbines are 2000 kW that would be 2500 KVA.
The 1500 HP pumps will be about 1250 KVA with allowances for efficiency.
That meets some rules of thumb for starting a motor with no other load on the system.
When the pump motor is connected to the turbine generator, the load will most likely pull the frequency down. (If it doesn't pull the frequency down you have no worries.)
Assuming 60 Hz, when the frequency drops below 58 Hz the Under Frequency Roll Off feature of the Automatic Voltage Regulator will drop the voltage in proportion. This drops the load on the turbine and assists it it recovering speed. The voltage drop with frequency gives the motor a friendly Volts per Hertz ratio and avoids saturating the motor.
It sounds as if your turbines are well matched to your pump motors.
I expect that the system will work well. In any event please let us know how it works out when it goes into service.
Bill
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"Why not the best?"
Jimmy Carter