Converting diesel engine to run on LP. Anyone done this?

I have been in the vapor abrasive blasting business for about 4 years (retirement job). My unit is portable and the compressor is a Kaeser 375 cfm unit powered by a Kubota 100 hp turbocharged tier 3 industrial diesel . I just landed a long term commercial contract with a company to blast components that are used in their operation. It is a good gig and I won't be travel with the unit anymore so it is going to become stationary.

Anyone have experience with converting a mechanical injected diesel to run on LP? Pros/cons?. From what I have read it burns cleaner ,is more efficient , provides a bump in performance and you can extend oil service intervals longer and no more multiple fuel filters.

Right now oil and filter changes are conducted every 150-175 hrs.

TIA

 

Propane auto ignites under compression? I suppose it can in the presence of O2. Does the cost of propane make this reasonable? I always assumed that forklifts that use propane were only used due to exhaust concerns and that they used regular spark type engines.

 

Years ago, the GC I was with converted over two of the three Terminal tractors for the yard and interior usage to LPG. The road one stayed diesel because the tanks were just two forklift tanks and they didn't want to risk running out between buildings ( ~ 2 miles on public roads).

It was years ago and I don't remember it being all that difficult or expensive and for what they used them for, was cash well spent.

 

Compressor runs on electricity, supplied by Kubota gen that uses diesel?

Take gen out of picture; connect compressor to AC power sourced from local utility. Is it available, or do you live in Stickboy-like country?

 

That was my thought also, if it's stationary, run electricity to it?

 

Why not stay diesel?
Your service interval is very short, why so? You using oil analysis to determine it?

 

That's my thought. It must be pretty frugal on fuel and if you take care of it, it'll probably run forever. Why go thru the hassle ?

 

Diesel gen efficiency = ~40%.

1 gal diesel = $2.67, per nearby to me WM.

1 gal diesel = 40.7 kWh energy equivalence

x 0.40 = 16.2 kWh

Electricity here = ~ $0.12/kWh

1 gal DGE = $1.95 of electricity; no oil, filter changes, etc.


1.95/2.67 = ~ 27% reduction in operating costs on fuel alone

[edited to correct an earlier value]

 

This is likely a direct coupled compressor and engine. Similar to this
https://america.sullair.com/en/products/400hh-tier-4-final-portable-air-compressor

 

The engine powers a screwblower that makes the air.

The oil change interval is based on the owners manual. On big commercial jobs the compressor/engine gets worked hard. Kinda like a race or track day. People like doing the preventive maintenance. Oil and filters are cheap. Engine rebuilds and downtime aren't.

I was trying break down fuel consumption for both diesel and LP. I converted the hp (100) to KW and came up with 74 KW full load. Used a formula and came up with 5.7 gal of diesel per hour wide ass open. Variables such as hose length, psi at the nozzle, nozzle size and abrasive amount could change thing but the usage per hour amount is about right based on my fuel tank size (38 gallons). Still can't figure consumption on LP. If some one can figure that out it would be awesome.

Pain meds and math don't work well. Three weeks ago my 85 yr mother and I were hit from the rear while we were stopped at a light. She is fine but my back is jacked. Never had back issues in my life besides the occasional pulled muscle or just over exertion. Seeing the ortho surgeon tomorrow.

Yep except mine is a tier 3 no shitty ass emissions crap. The T4's have had all kind of issues with computer shit, DEF sensors and exhaust filter issues. Nothing like having your machine quit or go into limp mode while out on the job. I'm not sure they have them figured out and it added another 10-15 K to the cost of the compressors.

TIA

 

Use electric motor with hydraulic pump and use that to drive the blower

 

I'd have to drop some serious coin on e-motor and and I'm guessing the pump would be incorporated into a drive system. Cool idea but wouldn't be viable as I don't think I would have access to the voltage to drive such a big E-motor and all blasting is done outdoors.

The blower is a roots style design and essentially looks like a supercharger on ICE. Not sure of it's displacement.Maybe a 10-71 but it is definitely bigger than a 8-71. The blower or air end as some call it has a 375 CFM output. PSI of the air inlet side is constant 110 psi to the blaster control panel. The pressure in the blast pot must maintain a specific pressure for the best performance . The blast hose has a inside diameter of 1 in. I also use air that runs through a scrubber filter system the provides cool air to my protective blasting hood.

Thanks for the input.

 

In true beeb fashion, people are giving all kinds of answers to the questions that weren't asked. From this, I gather that nobody on here has any clue on how to convert diesel to propane. But that is OK, just keep telling the OP how to do it in a way that you feel qualified to give advice, no matter how wrong you are.

 

Ken, in my defense, a lot of assumptions had to be made. No specific config info was provided. And my numbers showed strong potential for increased economic performance.

If you want me to suggest a great production bike to race that will be tons of fun, I'll always say TZ250; 1996 or newer. I didn't know some of the requirements were the bike needs to be equipped with an electric starter and run on pump gas.

 

Gentlemen, I surely didn't start this thread to cause any kind of conflict. I appreciate everyones input.

With that being said y'all have a great Thanksgiving!

 

I’ve yet to see a compression ignition engine solely fueled by propane. Dual fuel diesel/propane is not uncommon.
But, given the OP’s aversion to emission technology. I suspect the additional complexity would become bothersome. Better to remain on the fringe of the topic.

 

No worries. I consider Ken a great guy and was just needling him a bit. I'm glad you started the thread as I've learned from it.

 

My blowers on my big vac trucks also require a lot of power to run when they are at max vacuum.

You're far better off buying OFF ROAD diesel in a fuel cell in a pickup truck bed and calling it a day......or put in a big tank and have it delivered.

My biggest is I think 2500 CFM 6"
Blower is driven hydraulically but off a 500 hp. Cummins and it's also running a couple other things at same time and the truck. Plus that is with 1.25" lines then you need large hydro tank (150gal) and coolers for the oil.

 

I would think electrically you could pull it off with ease if you have a good local pulley guy and run a belt /chainsystem with different size pulleys and a VFD for the motor

If you have to get propane delivered.......might as well stick with getting off road tax free diesel delivered and save all the work

 

A pump service company in OK/TX can provide you with answers, as they run CAT diesels on CNG to run generators that power well pumps. I’d say any of the big CAT service centers could at least get you pointed in a direction for conversion.