Fuel Gas Electric Pre-Heater 2

[reiszal]

Hi guys,
I have been surfing in the net for hours but still couldn't find the information about common or average inline gas heater efficiency. Could anyone in this forum group help me sharing their experience regrarding this issue? Maybe you guys know about the average or commonly assumed inline gas heater efficiency.

Thanks a lot guys!

 

[quark]

Generally electric heaters are 100% efficient (i.e 1kW electric energy gives out 1kW heat). But Joule proved that the process itself is very inefficient (no, not oxymoron. You can get upto 5kW heat from 1kW electic power by using a heat pump)

Regards,




Believe it or not : Though he couldn't prove, Einstein never agreed with Heisenberg on his Uncertainty Principle.

 

[speco]

Reiszal,

The fuel gas heaters that I have seen used in practice were heating fuel gas going to an engine-driven compressor. The engine typically has a jacket water cooling loop with hot glycol available at around 180 deg. F. This glycol needs to be cooled anyway, so some of the jacket water is used to heat the fuel gas. It's like free energy.

Regards,

speco (

http://www.stoneprocess.com)

 

[mb44]

Inline natural gas heater can be considered to be 100% efficient, however you will have voltage fluctuation that will effect the power you get out fronm an electric heater. I have purchased lots of these from Heatex and Eltron. Tell me more about your application and I will put you in touch with the right people or help if I can

email; mb@ogsl.com

 

[reiszal]

Hi mb44!
Thanks a lot for the very useful info. My application for the fuel gas inline heater is to preheat the hydrocarbon gas that we tapped from the main production manifold (offshore drilling / riser gas platform). This preheating purpose is to make sure that the natural gas that we are going to supply to the Capstone Model C30 Microturbine will not going to form hydrate (be it Type 1 or Type 2)due to two times of decreasing the incoming pressure from the manifold via self-regulating PCV. As we all know the pressure of the feed stream (gas)to the gas turbine is dependent on the type of the turbine that we used. In our case we only use microturbine type since the platform that we are designing now is an unmanned type.

And at this moment of time we are looking for an electrical inline gas heater type. Based on our study, the required duty for the preheater that we are looking for is about less than 1.5 kW. I hope the information that I shared is sufficient enoguh for you mb44, but if you wanna know more feel free to ask.

One more thing mb44, I am interested with the info regarding the voltage fluctuations which will affect the power output of my electric heater. Let say if this scenario happen to our Fuel Gas inline preheater, is there any means that we can control our preheater; i.e. trip the main heater and run the stand-by (meaning that we have to propose to the client to install two preheaters - which i think is not the best idea), or is the effect is not that too much to the heater? Or do you mind sharing the experience that you have regarding the control of such electric heater.. please.
Last but not least mb44, are these two Heatex and Eltron have the kind of heater that I am looking for - 1.5kW or may be less?


Quark,
Thanks for the info.

Speco,
Thanks for your experience sharing. But anyway my concerns at this moment is not the energy requirement for our heat exchange equipment since we have decided to use electrical type heater. We are only concerns about the efficiency. But anyway thanks for your kind reply. Stay cool!

 

[mb44]

1.5 kW thats small. Most of the units I have used are sort of 50 to 2500 kW pre heating gas for GTis or engines.

You would need to speak to potential vendors about the best way of controlling this. I would suggest buy a 5 kW unit that way what ever the voltage flucctuation you will get 1.5 kw out. Probably control with a thyristor (SCR if you are in the US), this varies the power output so will enable a 5 kw heater to operate at 1.5 kw normally. Control this via downstrem or differential temperature controller in the heater control panel or DCS, depending on if you need to give your turbine a minimum temperature or dewpoint + K superheat.

Also remeber as the heater will be in a hazardous area if you are in Europe it needs to meet ATEX and hazardous area requirments

There is a calculation for voltage drop and power but basically a 10% voltage drop means you need a heater oversized by 23%

The other thing to consider is that the heater will need to go in a little pressure vessel, flanged connections, design coded etc

Contact details for Heatex are John Cawcutt phone + 44 (0)1953 886268 or email john.cawcutt@heatex.co.uk, tell him I gave you his contact details, he should be able to help.

 

[reiszal]

Thanks mb44!