S
Dear all,
I have idea about how does the hydrogen purity affects gas turbine generator output. If i am not wrong it is this way by reading the threads from control.com and by Googling.
Hydrogen has molecular weight of 2, while Air is 29. it does mean Air weighs more than 14 times compared to Hydrogen. so even relatively low levels of air considerably increase the density of the gas mixture. Air is the most likely impurity to affect hydrogen within the generator casing. For each percentage point increase of Air impurity in Hydrogen will have a 14 times exponential increase in Gas density within the Rotor space in the Generator. Thus, the increased drag caused is also exponential in value. The best performance of a Turbine Generator (TG) can be derived when the Hydrogen purity within the TG is maintained near constant at 98 to 99.5%.
Even small reductions in hydrogen purity directly correlate to increased windage friction losses inside the turbine generators, which have a direct impact on a power plant's bottom line.
Impurities in a hydrogen supply increase the density of the gas, and the density of a gas affects its ability to remove heat.
This can be understand <pre>
Gdens = (Hpur x 1) + (Abal x 14.4)
Where: Gdens = Increase in gas density(%)
Hpur = Purity of hydrogen in generator casing (%)
Abal = Balance of impurity (air) in generator casing (%)</pre>
Roughly, for every 1 percent of air trapped in a hydrogen-cooled generator casing, there's an average 250 kW drop in power output.
Now the thing is that there was some experimentation going in our plant...how does hydrogen purity affects gas turbine generator output for every 1% drop in purity.....
Management decided to test the unit in combined cycle at 99%, check whats the performance. and subsequently for every 1% drop, check whats the unit performance again...like this ways from 99 to 95%.. we as a performance engineers can understand how difficult it is justify this 1% drop against unit output....
so they are asking us to make report for every 1% drop whats the unit performance at base load condition.
what is the wise way to convince them as many other factors should be in consideration while calculating the unit performance...simply ambient temp, humidity, pressure, power factor, inlet dp, exhaust dp, etc. the above said parameters should be constant to calculate the difference in unit performance for every 1% drop in hydrogen purity?
Please help some one.
CSA sir...how to respond to this type of challenges. give some wise answer.
Thank you in advance
I have idea about how does the hydrogen purity affects gas turbine generator output. If i am not wrong it is this way by reading the threads from control.com and by Googling.
Hydrogen has molecular weight of 2, while Air is 29. it does mean Air weighs more than 14 times compared to Hydrogen. so even relatively low levels of air considerably increase the density of the gas mixture. Air is the most likely impurity to affect hydrogen within the generator casing. For each percentage point increase of Air impurity in Hydrogen will have a 14 times exponential increase in Gas density within the Rotor space in the Generator. Thus, the increased drag caused is also exponential in value. The best performance of a Turbine Generator (TG) can be derived when the Hydrogen purity within the TG is maintained near constant at 98 to 99.5%.
Even small reductions in hydrogen purity directly correlate to increased windage friction losses inside the turbine generators, which have a direct impact on a power plant's bottom line.
Impurities in a hydrogen supply increase the density of the gas, and the density of a gas affects its ability to remove heat.
This can be understand <pre>
Gdens = (Hpur x 1) + (Abal x 14.4)
Where: Gdens = Increase in gas density(%)
Hpur = Purity of hydrogen in generator casing (%)
Abal = Balance of impurity (air) in generator casing (%)</pre>
Roughly, for every 1 percent of air trapped in a hydrogen-cooled generator casing, there's an average 250 kW drop in power output.
Now the thing is that there was some experimentation going in our plant...how does hydrogen purity affects gas turbine generator output for every 1% drop in purity.....
Management decided to test the unit in combined cycle at 99%, check whats the performance. and subsequently for every 1% drop, check whats the unit performance again...like this ways from 99 to 95%.. we as a performance engineers can understand how difficult it is justify this 1% drop against unit output....
so they are asking us to make report for every 1% drop whats the unit performance at base load condition.
what is the wise way to convince them as many other factors should be in consideration while calculating the unit performance...simply ambient temp, humidity, pressure, power factor, inlet dp, exhaust dp, etc. the above said parameters should be constant to calculate the difference in unit performance for every 1% drop in hydrogen purity?
Please help some one.
CSA sir...how to respond to this type of challenges. give some wise answer.
Thank you in advance