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Need some help choosing a hydrogen generator?

14 Jan 2014

As customers continue to switch to gas generators as their main source for hydrogen, we often get asked for assistance to help them make the right choice.  As a result, I decided to write this post to help our customers in their selection.

 
H2 Generator

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In most cases, choosing the appropriate generator is as simple as answering two questions:

 

1.  What purity do you need?  In other words, are you going to use the hydrogen for GC carrier gas, fuel gas, or both?

If you are only going to use the hydrogen for fuel gas (or for some other purpose where the purity is not critical), we suggest a Parker Balston PEM generator.

If you are going to use the hydrogen for carrier gas (where high-purity is critical), we suggest a Parker Balston H2PEMPD generator.

 

2.  What flow rate and pressure is required?  After all, before you can select a generator, you need to have this information.

For most GC set-ups, seldom is maximum output (delivery) pressure critical unless the instrument(s):

A.  Are located several rooms away from the generator where pressure drop across the tubing may drastically decrease delivery pressure.

B.  Are using long packed columns which require high head pressure.

C.  Are using small internal diameter, or very long, capillary or micropacked columns which require high head pressure.

 

In most cases, flow rate will determine which generator you would choose.

A.  In order to calculate the maximum flow rate needed, you need to carefully look at each instrument to determine its total hydrogen flow rate used during peak consumption (which may include fuel gas, column carrier gas, and hydrogen exiting the split vent line).

B.  Once the flow rate is calculated for each instrument, add these up to determine the total flow rate needed for all instruments.

C.  Finally, multiply a buffer factor* of between 1.5 and 2.0 to this total flow rate.

* Example: if you calculated that the total hydrogen flow rate needed for all instruments is 300mL/min, you would want to choose a generator with an output of somewhere between 450mL/min and 600mL/min.  In this case, we would suggest one of our generators which have an output of 510mL/min (note: 1mL/min = 1cc/min).

 To read more about these generators, you may want to review Gas Management Supplies for GC Labs. If you still have questions, email us at technical service .

Thanks for reading.