Westinghouse 501DA Fuel Conversion 1

[turboco1]

Has anyone experience or knowledge of converting a Westinghouse 120mw combustion turbine model 501DA from liquid fuel to LNG or dual fuel? I'm looking for tech tips/advice for or against a conversion this way on this model based on experience. There is a user's group for this model but no website...

Regards

 

[Murphy99]

I worked for Westinghouse (Hamilton) as a Controls FSE from 1999 to 2001.
Mostly 501Fs and some dual fuel. What do you want to know?

 

[turboco1]

Thanks. I found a supplier of fuel nozzles and am currently looking into doing a combustion inspection to determine the requirements to convert from fuel oil to LNG/residual.

 

[Murphy99]

Cool. Residual? Is that the "high ends" off a column?
My last trip was doing Prod Mods to five D5s at Sweeny, a Phillips Refinery at Old Ocean Texas.
Do you have SUN workstations or WDPF Classic?
Lots of sophisticated software for the "Hydrogen"

 

[turboco1]

I'm actually involved at the request of an interested buyer of this CT... the goal now is to determine the economics of converting from no.2 fuel oil to: 1)no.6 heavy fuel oil which requires preheat, 2)orimulsion, 3)natural gas and 4)methane

The control system is "PowerLogic"? which I uinderstand is an old relay system.

 

[Murphy99]

The 501Ds are good machines with a reasonable base load.
They were the first Dry Low NOx machines. I don't know if Siemens is converting them to TXP (Siemens control system)or not.
If your customer is serious the first step is to look into a control system - WDPF(spares) or after market. Should be some WDPFs from TXP converted 501Fs around. Emerson bought Process Control Division after Siemens bought only the turbine division. Emissions are a big deal if you are in the US or Canada.

 

[turboco1]

Already have a aftermarket control system supplier and turbine nozzle manufacturer if the job moves forward.

Currently evaluating "Orimulsion" and LNG as fuel alternatives. The Orimulsion looks like a good alternative source from Venezuela. I'm looking for a converted Orimulsion unit in Venezuela now... any leads let me know... just to get $$numbers on fuel operating costs.

 

[ScottyUK]

WDPF is still an active product supported by Emerson. No problems with spares except on some really old stuff like the Multibus products which are legacy items incorporated into WDPF as part opf the DEH system for the steam turbines, for example. A CT in all likelihood uses standard parts which are currently available. We run tri-fuel 701DA's which are a 171MW non-DLN 50Hz design built under license by MHI in Japan.



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If we learn from our mistakes,
I'm getting a great education!

 

[turboco1]

What about any CT comparisons of burning

..."Orimulsion" verses no.2 Fuel Oil?

or ...natural gas vs no.2 Fuel Oil?

or ...methane gas vs no.2 FO

or ...no.6 FO vs no.2 FO?

 

[Romefu12]

Turboco1
Your initial e-mail states you are pondering converting the 501DA from liquid fuel to LNG or dual fuel?

This retrofit is a relatively simple option from a mechanical standpoint (without discussing fuel nozzles) and controls I understand are still available as well.

While dual fuel is an economical option in todays market it would be my opinion that you seriously research the other fuel options that your client would be wanting to pursue and start there.

There are many operational issues concerning different Low Heat Value (LHV) fuels such as no.6 heavy fuel oil, orimulsion etc. The fuel of choice for this unit would be natural gas. With natural Gas you would get the longest service life out of the Hot Gas Path (HGP)components however fuel costs are higher.

With LHV gases and distilate fuels there is normally the introduction of water or moisture into the combustion system which, when fired, results in byproducts of combustion sticking to the Hot Gas Path components increasing the heat transfer coeficients and subsequently overheating the components. This will drive up maintenance costs you would not get the longest service life out of the Hot Gas Path (HGP)components.

With other LHV fuels there must be a total mass flow increase in the unit to obtain the same performance therefore more air is needed to sustain combustion in the increased fuel flow. The 501D was a pretty robust machine and usually performs well with distilate fuels as there compressors were designed for the reduced surge margins of light distilates. Depending on the age and degredation of the engine this could cause problems with even lower LHV fuels. You do not mention the features of the engine such as firing temperature, whether the engine is equipped with Variable Inlet Guide Vanes, etc. therefore I cannot make a estimate of tuning issues. The Variable Inlet Guide Vanes will make tuning on Natural Gas much easier.

Whether you choose Natural Gas or other LHV fuels be sure that your supplier of fuel nozzles will supply you the correct swirl caps and emulsion spray nozzles for the particular fuel application and have the sets of nozzles flow tested, corrected, and certified in sets by the supplier before installation.

Hope this helps
Regards
Romefu12

 

[turboco1]

Romefu12,

Thanks for the post.
In this case, fuel oils are subsidized by the government and gas is not... residual is the best option.