Turbine Steam Usage problem
Turbine Steam Usage problem
(OP)
I'm trying to spec out some new turbine steam trip valves for a client. The valve manufacturer is requesting the steam flow rates through the turbine. I've asked the client for the information and the Process engineer has given me a couple of numbers based off of the pump data sheets that have some basic turbine numbers on them as well. I'm having an issue understanding the Process engineer's response.
The data sheet states the steam flow rate as
85.5 lb/BHP/hr
The process engineer said in the email that this is "85.5 MPPH".
Is MPPH = mass pounds per hour? If so, is this correct? I'm not that familiar with these units but it seems like I'd need to multiply 85.5 lb/BHP/hr x 150 hp (from the data sheet) to get the lb/hr?
Also, he only had the data sheets for 2 out of the 5 turbines I've requested. I am using a Turbine Steam-Consumption calculator to estimate the steam flow rate for my other turbines as well as to compare with the numbers given on the 2 data sheets that I do have. Using the following inputs, the calculator is giving me numbers that are no where close to 85.5 x 150 hp lb/hr.
P in = 600 psig
T in = 700 F
P out = 250
T out = 520
Power = 150 hp
calculated steam usage = 5036 lb/hr
What am I missing?
The data sheet states the steam flow rate as
85.5 lb/BHP/hr
The process engineer said in the email that this is "85.5 MPPH".
Is MPPH = mass pounds per hour? If so, is this correct? I'm not that familiar with these units but it seems like I'd need to multiply 85.5 lb/BHP/hr x 150 hp (from the data sheet) to get the lb/hr?
Also, he only had the data sheets for 2 out of the 5 turbines I've requested. I am using a Turbine Steam-Consumption calculator to estimate the steam flow rate for my other turbines as well as to compare with the numbers given on the 2 data sheets that I do have. Using the following inputs, the calculator is giving me numbers that are no where close to 85.5 x 150 hp lb/hr.
P in = 600 psig
T in = 700 F
P out = 250
T out = 520
Power = 150 hp
calculated steam usage = 5036 lb/hr
What am I missing?





RE: Turbine Steam Usage problem
RE: Turbine Steam Usage problem
is MPPH equivalent to Lbs/hp/hr like he's saying? That doesn't seem right.
RE: Turbine Steam Usage problem
Best of luck!
RE: Turbine Steam Usage problem
You are missing the information that you need to do your job correctly.
If you suspect that the process engineer you have already corresponded with is not the right person in your client's organization to provide that information then find the right person.
If there is no right person then make arrangements to get the information yourself.
Somewhere in the facility there is certainly a file that contains the original design parameters. Of course maybe no one knows where it is.
If you can't find it then you'll need to directly measure.
You are unlikely to get the information you need from random strangers on the internet.
RE: Turbine Steam Usage problem
Am I incorrectly thinking about this?
RE: Turbine Steam Usage problem
I strongly recommend picking up the phone and talking to the process engineer (yes, I'm an introverted engineer and don't like phones either, but sometimes you have to.) Clear up your units. Random strangers on the internet cannot interpret this for you (well we could, but just because someone confirms your math doesn't mean you've met what the process engineer wants. He might really want 85 MPPH.) Being right sometimes is not the important thing -- sometimes what's important is getting the process to do what the customer wants.
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RE: Turbine Steam Usage problem
** MPPH Machu Picchu Pueblo Hotel
** MPPH 2-Methyl-1-Phenyl-2-Propyl-Hydroperoxide (biochemistry)
* MPPH Magnesium Potassium Phosphate Hexahydrate
RE: Turbine Steam Usage problem
RE: Turbine Steam Usage problem
The current Metric standard uses a prefix for thousands (k, or kilo), so if we want to express 15,000 PPH, it can be written 15 kPPH
The trouble then starts with the standard Metric designation for millions (M, or Mega)
the USA industry for several decades uses "M" for thousands (based on Roman number designations), which in current industry is sometimes mistaken for "Millions" by Metric oriented people.
As a result, the USA standard is currently to express "Millions" as MM, such as 5,000,000 PPH = 5 MMPPH In this case the older (Roman "M") designation becomes 1000 x 1000 = Millions, and there is no conflicting Metric prefix to be confused with. Similarly, we use kPPH for thousands, and there is again no conflicting interpretation.
The confusion for the issue here is clearly that someone is mixed up on the numbers, 85.5 LBm/BHP-hr gives 12,825 PPH steam flow for a 150 Horsepower machine, a fairly high, but not unreasonable steam consumption for a small turbine. But the same data supplied has 5036 PPH steam consumption stated, and evidently the engineer stated "85.5 MPPH", which in any interpretation would be either 85,500 PPH, or 85,500,000 PPH, which are values far too high for anything close to reasonable. So in conclusion, the data needs to be sorted by someone who actually knows what is what.
RE: Turbine Steam Usage problem
We got it sorted out, my inclination was correct and the process engineer apologized for being quite confused on the issue.
RE: Turbine Steam Usage problem
RE: Turbine Steam Usage problem
The quantity such as 85 lb/BHP/hr is a "steam rate" for the turbine in question -- the amount of steam flow required (lb/hr) per unit of power (hp). It is represented as lb/hp-hr, or (somewhat sloppily & confusingly) lb/hp/hr.