Propane VS Diesel in ~20-30kW generator ranges.

kwired

Electron manager
Location
NE Nebraska
Ask any OTR driver to answer your question.
Not all that familiar with this or it's problems, but how does it create same problems as gasoline washing cylinder walls in a gas engine if it is injected into the exhaust? Not saying it doesn't have some other problems - again I really don't know much about it.
 

hillbilly1

Senior Member
Location
Atlanta,Ga
Not all that familiar with this or it's problems, but how does it create same problems as gasoline washing cylinder walls in a gas engine if it is injected into the exhaust? Not saying it doesn't have some other problems - again I really don't know much about it.
Not saying it DEF causes cylinder wall washing, The whole DEF thing greatly reduces the reliability of a Diesel engine, engine shutdown resulting from malfunction is much greater than gas or lpg. Cummins is very susceptible to bad DEF, Ford has turbo issues that are exasperated by DEF. DEF also freezes, has very limited storage life, especially at high temperatures. GM has the best system, but it can’t overcome all of DEF’s shortfalls.
 

kwired

Electron manager
Location
NE Nebraska
Not saying it DEF causes cylinder wall washing, The whole DEF thing greatly reduces the reliability of a Diesel engine, engine shutdown resulting from malfunction is much greater than gas or lpg. Cummins is very susceptible to bad DEF, Ford has turbo issues that are exasperated by DEF. DEF also freezes, has very limited storage life, especially at high temperatures. GM has the best system, but it can’t overcome all of DEF’s shortfalls.
I will agree it introduces potential problems, just not with the engine itself. Some those problems result in engine not performing well, but is more of a result of sensors telling engine to not run so well. Like when you have a truck and it is out of DEF, default operation often is to still allow it to run but with limited output, nothing wrong with the engine itself though.
 

Todd0x1

Senior Member
Location
CA
I have two fords with DEF a 2015 and a 2017. Zero issues. Although I did purchase 200k mile factory warranties with them just in case. The newest gen engines are very complicated. Open the hood on one of these and it looks like a rocket engine -all densely packed pipes and harnesses.

I had a generator with no DEF/SCR but it did have a DPF. That thing was a nightmare, the DPF would clog from running the unit lightly loaded and the engine couldnt get hot enough to regenerate so it would shut down.
 

Russs57

Senior Member
Petersonra, I live in an area with a lot of hurricanes. I have been without power for over a month at my house. Hurricanes don't happen every month but 72 hours is nothing these days. Most numerous I can recall was ten within a 12 month period, but spread out over two hurricane seasons.

Here, certain gas stations...grocery stores.....pharmacies....etc, are required by law to be at least "generator ready".

At work at a hospital on the ocean. I have 6.75 megawatt of generator capacity and will bring in more if a serious storm is coming. I typically have 50,000 gallons of diesel on site and don't consider it enough.....but it meets the letter of the law.

I have no clue about what a serious blizzard means in terms of loss of power nor the need to have power to ride out such an event in safety.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
I live in northern illinois. we get blizzards, tornados, ice storms, and assorted other weather events, but no hurricanes.

I bought my house in 1986. I doubt I have been without power for more than 100 hours total since then. maybe not even 50. Most outages have been for less than an hour and there have only been a handful of very short outages since the power lines out front in the road were moved underground 8 or 9 years ago, and I only noticed them because the microwave display was blinking and the computer rebooted.

There are cases where having better power protection is well worth it and if you suffer from loss of power for long periods of time in your area you might well have a good case to get a generator. But for most people, there just is not all that much need.
 

brantmacga

Senior Member
Location
Georgia
Occupation
Electrical contractor
Also, the Kohler (and probably the Generac) diesel generators run at 1800 rpm, while the propane ones are running at 3600 rpm.
Generac offers 1800 rpm in liquid cooled LP/NG generators. Cost is roughly 15% higher than 3600 rpm versions. It’s worth the added cost not only for sound reduction but longevity.


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tortuga

Senior Member
Location
(44.057116, -123.103394)
Occupation
field supervisor
Generac offers 1800 rpm in liquid cooled LP/NG generators. Cost is roughly 15% higher than 3600 rpm versions. It’s worth the added cost not only for sound reduction but longevity.


Sent from my iPhone using Tapatalk
Interesting thanks, that must be their protector line?
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
Interesting that Junkerack does not make any diesel gensets for the US market. Everything is gas/propane/NG and single phase. Their diesels can be had in 3 phase but they are all 50Hz and not for sale in the US or CA.

-Hal
 

tortuga

Senior Member
Location
(44.057116, -123.103394)
Occupation
field supervisor
Interesting that Junkerack does not make any diesel gensets for the US market. Everything is gas/propane/NG and single phase. Their diesels can be had in 3 phase but they are all 50Hz and not for sale in the US or CA.

-Hal
No its just that their website is kinda confusing, these can be used in the US:
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
Keep in mind by the time you turn a gallon of diesel into electrcity, in very rough terms a 25 kw genset run at half load is going to use about 25 gallons a day.

That presents a significant storage problem for a typical residential user who expects to be able to use it for more than a few hours at a time.
 

oldsparky52

Senior Member
At work at a hospital on the ocean. I have 6.75 megawatt of generator capacity and will bring in more if a serious storm is coming. I typically have 50,000 gallons of diesel on site and don't consider it enough.....but it meets the letter of the law.
I am curious about some things.

Do you "polish" the fuel? If yes, how often?

When you get a fuel delivery, is it dumped into the tank with other fuel or is it segregated in it's own tank until your testing is complete? Do you test the delivered fuel prior to attempted usage?

I ask because I sat with a real fuel system engineer and he was telling me the way he designs critical fuel systems (like for hospitals, data centers) and I had never considered some of the things he mentioned.

I also heard a story a while back where the underground tanks at a gas station lost all of there fuel (30k gallons) when the area was flooded. Apparently the tanks openings (fill?) were not all water tight. Water heaver than gas so ... they lost 30k of gas and had 30k of water instead. Story sounds a little dubious, but it makes a valid point.

I'm also curious, are your generators pulling from the UG storage tank (I assume yours are underground) or from a day tank that the underground feed?

Do you have just one piping system from the UG tanks or is there a redundant piping system?

I used to do fuel work and it is interesting to me what type of operations are out there.
 

oldsparky52

Senior Member
I think if you don't use it, you have to get it pumped out and replaced now and then. Not sure how often.
I think you are correct, but cleaning it (polishing) and additives can extend the shelf life. With the cracking methods being used now (at the refinery) the shelf life has come down from what we had decades ago.
 

tortuga

Senior Member
Location
(44.057116, -123.103394)
Occupation
field supervisor
Keep in mind by the time you turn a gallon of diesel into electrcity, in very rough terms a 25 kw genset run at half load is going to use about 25 gallons a day.

That presents a significant storage problem for a typical residential user who expects to be able to use it for more than a few hours at a time.
Note it looks more like 32 gallons a day to be on the safe side, A 150 gallon diesel tank can be had for ~700-800 USD. The local propane delivery folks around here wont 'rent' tanks for generators, as they make money on deliveries. I have gotten people 500 and 1000 gallon tank upgrades whom alredy had service but they still charged around 1500.
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Russs57

Senior Member
Do you "polish" the fuel? If yes, how often?

Yes, once a year.

When you get a fuel delivery, is it dumped into the tank with other fuel or is it segregated in it's own tank until your testing is complete? Do you test the delivered fuel prior to attempted usage?

Sadly, it is dumped on top of other fuel. It isn't tested but is "supposed" to be treated.

I ask because I sat with a real fuel system engineer and he was telling me the way he designs critical fuel systems (like for hospitals, data centers) and I had never considered some of the things he mentioned.

There is a lot to it, especially on the leak detection side.

I'm also curious, are your generators pulling from the UG storage tank (I assume yours are underground) or from a day tank that the underground feed?

The only time I have not seen day tanks used are when the fuel tank is local to the engine, like a skid mount package with a tank under the generator.....or a diesel fire pump with a tank in the pump room. Some of my tanks are above ground and some are below.

Do you have just one piping system from the UG tanks or is there a redundant piping system?

In the past all my systems were underground tanks with redundant piping. These days I'm under new ownership so I have above ground tanks without redundant piping.

I used to do fuel work and it is interesting to me what type of operations are out there.

Biggest differences I see are in coax hose vs steel pipe with fiberglass pipe for secondary containment. Also leak detection system based on maintaining a certain pressure on pipelines at all times vs systems that need to prove a certain PSI and GPM within a certain time period. To a smaller extent if a system monitors the presence of water between primary and secondary hose/pipe and containment.

IMHO the problems are the end users often don't fully understand their protection systems and how to quickly get out of a problem. Heck I have even seen installations where the entire fuel delivery system wasn't on emergency power! Nothing like coming to work with all generator batteries totally dead and all fuel filters plugged solid and no normal power available.
 

Open Neutral

Senior Member
I weighed this for a friend in NoCal about a decade above.

Fuel storage is a non-trivial issue.

At least in his area, your choices are propane buried or aboveground vs. Diesel aboveground. Don't even think of burying a Diesel tank in any watershed area unless you want to spend major $$$$$ on getting the needed Federal/state/local approval. From what I was told, buried propane tanks were the opposite, a non-issue.

Any aboveground tankage was a threat in a wildfire, but buried propane was seemingly not. It might overpressure vent and burn, but was unlikely to explode.

Propane stores forever. Diesel is another kettle of fish. You must groom the fuel, i.e. filter it and inject biocide, or you are SOL. But I have wondered what the longevity of Diesel is, long-term. In the late 1960s-1990, AT&T Long-Lines built underground bunkers every 150 miles along Her transcontinental coaxial cable routes. These were designed to survive WWIII: 30 ft down, 2 ft thick walls, 40,000-160,000 ft^2, rated for 10+ psi shock waves, and had dual 700 KVA White Superior Diesels or later, multiple Solar Corp. turbines. To keep those facilities going for ~3 weeks, they had 85,000-150,000 gallons of Diesel on site. While they groomed the fuel, what's it like after 5-10 years? I'd think you could inject a few gallons of light ends such as gasoline but never heard of it.

(When Long_Lines sold them off, they pumped the tanks out and filled them with cement slurrry; a retiring employee told me the line of mixer trucks was "endless...")
 

Todd0x1

Senior Member
Location
CA
What do the datacenters do with their diesel? Some of these places have hundreds of thousands of gallons onsite. I can't really see them replacing all that every few years. I think they polish, test, and treat.
 

hillbilly1

Senior Member
Location
Atlanta,Ga
What do the datacenters do with their diesel? Some of these places have hundreds of thousands of gallons onsite. I can't really see them replacing all that every few years. I think they polish, test, and treat.
They burn through a lot of it. At minimum, weekly exercising, at least one hour. Some under load, some not. They do test the fuel regularly.
 
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