Dual Fuel Generation 1

[Peter Mather]

Hi all,

I'm looking to upgrade the power gen on out oil processing facilities.
The obvious choice is gas engine but I need to also be able to operate on diesel in the event that the fuel gas system fails.

So I'm in the market for 4 x 2.5MW; 400V; 50Hz gas/diesel reciprocating machines.
To date I found only one supplier in Ghent, Belgium but would appreciate input from the forum on other options.

Thanks in advance.

 

[LittleInch]

You might find a better option is a gas / distillate engine like kerosene, but ask the manufacturers what they provide.

Diesel to gas sounds like a different type of combustion system (spark versus high compression fuel injection into the cylinder, but there seem to be a number of engines, CAT, wartsilla, various Indian and Chinese vendors supplying this.

Or use LPG as a back up?

Why would the fuel gas system fail? cheaper to have a 2 x 100% system.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[cranky108]

Gas/LPG/Natural gas is a better switchable scheme.

 

[LittleInch]

Probably need to be a bit more precise about (natural) gas / methane versus gas(oline)....

I mean natural gas when I say "gas" and petrol when I mean gasoline....

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[wayne440]

My (limited) experience in the power generation industry has been that "gas" = gaseous fuels (natural gas, propane etc.) and that "gasoline" = liquid fuels sold as gasoline (gasoline, E10, etc.)

 

[FacEngrPE]

The other approach is Natural Gas + ignition by diesel pilot fuel injection.

https://dieselnet.com/tech/engine_natural-gas.php

Suggest this search

https://duckduckgo.com/?q=Lean+Burn+Otto+Cycle+dual+fuel+generator&t=lm&ia=web

 

[waross]

The other approach is Natural Gas + ignition by diesel pilot fuel injection.

I first encountered a red-neck version of this in Northern Canada in the mid 80's.
In the winter's truckers had an issue going from a high humidity area to a lower temperature area.
Moisture in the brake-lines would condense and then freeze.
This tended to happen in control valves when releasing air.
The condensate would freeze and stick the valves.
This often led to the brakes being applied.
Northern truckers often carried a "Tiger-Torch" to enable them to thaw frozen brake valves.

An old trucker's trick was to carry the propane tank in the cab.
The torch would be taken off of the hose and the hose passed out the passenger side window and stuck into the air cleaner.
When the driver wanted to pass a more powerful truck on an up-grade, he would reach over and crack the propane valve open.
The addition of propane to the intake air often allowed an engine to develop more HP than a nominally more powerful engine.

And about the same time I heard of an LNG experiment.
A trucking company had a regular freight haul between two cities about 150 miles apart.
They outfitted some trucks with insulated LNG tanks and ran the route using mostly LNG for energy.
Just enough diesel fuel was used to ignite the gas.
The tanks were insulated but not refrigerated.
Vaporizing the gas for use kept the liquid cool and the vapour pressure down.
It was a use it or lose it system.

With a suitable diesel engine, the diesel fuel governor would be set at idle.
The speed and energy output would be controlled by the amount of gas vapour added to the intake, by a governor controlled control valve.
On the failure of the gas vapour supply, the diesel fuel governor would be set to working speed.
I apologize for providing anecdotes rather than hard information and links.
However, you may find it rewarding to pursue and research this approach.
I do hope that your intended gas supply is not sour gas.
The engine will not last very long burning sour gas.


--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[Peter Mather]

Thanks all but as i have been less than definitive let me add more detail
Being a Brit, when i say 'gas' I mean natural gas and not gasoline.
Our engines need to run on both natural gas and diesel.
The natural gas has a predominantly methane base and comes from cleaning up associated gas that comes from the oil wells
The gas is treated with amine to strip the H2S and CO2 plus other contaminants.
Tha Amine system may go out for maintenance which, to answer LittleInch, is why we would lose the fuel gas.
Our production facilites are extremely remote and are self sufficient.
So whilst I appreciate the comments I'm not looking to change the fuel source to anything different, just wanted to understand if anyone has experience of vendors who can supply gensets that can run on 100% natural gas or 100% diesel.
Have a good day.

 

[waross]

I understand, but do you realize that the diesel ignition sets use very little diesel fuel to ignite the methane.
There is a wide choice of industrial diesel engines that may be suitable for diesel ignition.
The controls may be set up to convert seamlessly from diesel ignition to full diesel, under load.
The savings in initial cost and parts down the road may support the cost of diesel fuel.
I may be wrong, but diesel ignition-methane fuel sets may be something to ask about when talking to vendors.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[waross]

It may be worth a call to Cat to see if this is suitable for diesel ignition.

Link

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[LittleInch]

Peter,

Appreciate you're looking for suppliers, but one issue you face with that sort of gas supply is that it is too rich for most engines. Natural gas engines tend to be based on sales gas gas, I.e. quite a low CV compared to associated gas. That could be why you're not getting many takers. What is the composition and CV of the gas?

Last time I did something similar it was a nightmare trying to find an engine that would accept our gas as there was too much C2,C3, and C4 in it.

Ended up with a gas turbine which might be an option as they can burn dual fuels, but prob not diesel.

Think you might be better off installing a diesel backup if you find a gas engine to burn your unusual fuel.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Peter Mather]

Thanks all
I have approached CAT. they only produce an engine that takes a 70% gas and 30% diesel blend so a non-starter or derates by 50% on gas only.
Regards fuel gas compostion we will install a fuel gas conditioning skid to drop out any liquids etc and ensure compatibility with whatever engine we select.
Turbines are a posibility but too much CAPEX.

 

[FacEngrPE]

These suppliers make dual fuel generator systems for the power market.

Wärtsilä

https://www.wingd.com

MAN Energy solutions

https://www.man-es.com/energy-storage/products/dual-fuel-engines

Cummins

https://www.cummins.com/engines/qsk50-dual-fuel?v=1221

Caterpiller

https://www.cat.com/en_US/by-industry/electric-power/ep-prod-ser-guide/dual-fuel.html

And Others

See also Gas Turbines, you can get them in your size range, if you can tolerate the lower efficiency.

https://www.solarturbines.com/en_US/products/power-generation-packages.html

The market for these engines seems to be small relative to single fuel engines, so it is necessary to spend time hunting through OEM websites to find the engines you are interested in.

Disclaimer I do not work with diesel engines much.

 

[LittleInch]

Peter,

Even with no liquids, it's the ethane and propane / butane quantities which cause the engine manufacturers the problem.

Unless you start refrigerating the gas to drop the higher C fractions, its a question of whether the engines can burn your gas, nit the other way around.

The only one I found was a Solar gas turbine. But maybe I had a very rich gas.

Let us know when you find one.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[TugboatEng]

There are a few dual fuel marine engines available. Himsen (Hyundai) and Wartsila both have offerings. They still require a small amount of oil fuel for gas operation as they use pilot injection instead of spark plugs.

 

[waross]

derates by 50% on gas only.

Or.
An engine sized for gas only operation will have adequate capacity to run occasionally on back-up diesel fuel.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[Peter Mather]

Thanks all for your input.
I've come back to ABC in Belgium do a 2500MW dual fuel engine
Wartsila smallest engine is 5.8MW so was way too big for us.
Will try Hyundai (thanks TugboatEng).
Have a good weekend.
Signing out......

 

[Hoxton123]

Dual fuel diesel engines used to be common on UK and other sewage works.

Started on diesel then added gas, reducing the diesel flow to about 10% of COP fuel flow. This diesel was the pilot fuel to ignite the gas / diesel mixture. In simple terms the gas was bled into the engine air inlet, so no compressor required.

Big advantage was that if no gas available from the digester, then could still generate on diesel fuel.

Disadvantages:
Low efficiency
Poor emissions
High capital cost,
large size as only worked with medium to slow speed engines

Modern high speed spark ignition lean burn engines, lower cost and higher efficiency.

Unlikely you will get the dual fuel engine past the Environment Agency exhaust emissions requirements

Medium Combustion Plant Directive will probably apply.

https://www.gov.uk/guidance/medium-combustion-plant-when-you-need-a-permit

Suggest you look at combination of spark ignition sets and standby diesels

 

[GregLocock]

I was puzzling over how to this and seemed to me that a supercharged (2:1) engine with a CR of 11 would be in the ballpark. That has the disadvantage that the NA NG operation would be less powerful than the diesel cycle. Oh well I've probably just reinvented the wheel.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[wcaseyharman]

I’m assuming you need the 4 for redundancy but the Siemens SGT400 is 10MW and I think they might make that in a tri-fuel: hydrogen, natural gas and diesel.