Dew point of gas-hydrogen blends

[siricosm]

Wow, that is a lot by the time you get to pure hydrogen, around 25C. This means that boiler running on pure hydrogen will not really need over sized rads to be condensing most of the time.

 

[Chuck]

Wow, that is a lot by the time you get to pure hydrogen, around 25C. This means that boiler running on pure hydrogen will not really need over sized rads to be condensing most of the time.

I think you must mean 15°C. Keep in mind that if the return temperature is at the dew point the amount of condensation will be negligible. It needs to be significantly lower to actually have a significant impact.

For example, at a dew point of 57°C the partial pressure of H2O in the combustion products will be 131 mmHg. A return temperature of 45°C will reduce the H2O SVP to 72 mmHg, which means that only about 45% of the H2O will be condensed.

According to my calculation, a boiler that runs on pure H2 with lambda = 1.1 will have a pp(H2O) = 240 mmHg. A return temperature of 55°C, which corresponds to SVP of 118 mmHg, will allow 50% of the H2O to condense.

 

[SJB060685]

I think you must mean 15°C. Keep in mind that if the return temperature is at the dew point the amount of condensation will be negligible. It needs to be significantly lower to actually have a significant impact.

For example, at a dew point of 57°C the partial pressure of H2O in the combustion products will be 131 mmHg. A return temperature of 45°C will reduce the H2O SVP to 72 mmHg, which means that only about 45% of the H20 will be condensed.

According to my calculation, a boiler that runs on pure H2 with lambda = 1.1 will have a pp(H2O) = 240 mmHg. A return temperature of 55°C, which corresponds to SVP of 118 mmHg, will allow 50% of the H2O to condense.

I'm liking your maths and clearly clarifies what I said above in my comment.

 

[siricosm]

Haha, yes, 15C.