German fuel situation and what to improve on it, 2.0

[marathag]

Benzene was popular as a racing fuel for drag racing and dirt track until outlawed in the 60s.

As was Hydrazine, normally a rocket fuel, used for a time in the '60s, when Nitromethane wasn't enough

 

[z42]

I believe that in the book "The Jet Race" the author asserts that the Germans never really had a shortage of jet fuel, kerosene, diesel fuel. They just had a shortage of machines that could use that fuel. They had no trouble filling up U-boats right up to the last day of the war.

IIRC fuel shortage was one of the reasons why the surface fleet spent most of the war holed up in harbors and fjords. Not saying that doing more sorties would have lead to any other outcome than the surface fleet being sunk sooner, but as it was they didn't really have that option.

VW bugs were modified to start on gasoline and then run on kerosene.

This was quite common before and after the war in things like boat and tractor engines, before diesels took over.

In India, at least a couple of decades ago, imported cars often had to be significantly detuned due to low octane fuel. Ostensibly the fuel standard was/is roughly in line with what you might find in the Western world, however it was common that gas stations illegally blended kerosine into the gas. Kerosine being pretty cheap as it was highly subsidized by the government so that poor people could afford to cook food. Wouldn't surprise me if other developing countries have similar issues.

German tanks were not diesel; Soviet tanks were. They could have switched their tanks over to diesel early in the war and and freed up high octane gasoline for the Luftwaffe.

I think German car manufactures were making diesel engines for cars already in the mid 30'ies, so the technology was definitely there. And an added advantage of diesel fuel for front line combat vehicles is that it's a lot less flammable than gasoline.

Of course, jet aircraft could have used the kerosene but their shortage of high temperature engine materials was even worse than the fuel shortage. Jet engines with an MTBF of around 25 hours was about the best they could do.

I think there is a bordering on plausible alternative timeline where they develop the high temperature alloys for turbines earlier, and stockpile nickel and other critical raw materials, and then they could have something like the He 280 deployed as the main frontline fighter mid war.

The big leap of faith needed for this, I think, is that they would have needed to start a huge R&D program for turbines and materials in the mid 30'ies or so.

 

[Deleted member 68059]

The most efficient, not best, and Perfect is the enemy of Good enough, is to use more of that Coal, as Coal.

Save on not needing those expensive Synth Fuel conversion plants.

Rather than taking the hit of 6+ tons of Coal to one ton of Liquid fuel, just use the existing Coal distribution network to power civilian and rear are Heer needs for moving things around.

They were using Horses, that was even more inefficient than Coal.

Let's compare Fuels
Diesel Engine efficiency is 38% for 1940s, Gasoline 26% for stuff that is roadbound.

Boilers and double acting cylinders like the Stanley Steamer or Sentinel Road Waggon, 9%

External Combustion just isn't that efficient. but is low tech, 1890s stuff.

Diesel has roughly 40% more BTU/lbs than Coal, depending on the grade, but it takes 4-8 tons of Coal to make 1 ton of synthetic oil, depending on the type of Coal, so you lose on using Synth plants, and not just of the fuel input stage.

Germany devoted over 4 million tons of Steel for the various Bergius hydrogenation or the Fischer-Tropsch process plants, and around 70,000 Workers at the start of operations at the start of the War.
From the USSBS

View attachment 720019
Bombing hurts.



The number of workers engaged in operating and maintaining the oil plants was 34,000 in June, 1938. The Karin Hall plan called for 6,600 additional operating personnel in mid-1939, to be increased to 66,000 by the second half of 1942.
In September, 1944, according to a statement by the Economic Group of the Fuel Industry, 20,000 persons were employed in crude production, 14,500 in crude refining, 89,200 in the synthetic industry, and 13,100 in coal tar distillation a total of 136,800. This estimate did not include miners, and probably omitted construction workers. Hence, some 200,000 workers were probably engaged in the production of oil in Germany. In the United States, about 270,000 persons were employed in drilling, producing, and refining oil in 1939, but this country's production then was more than twenty times the peak of 8,000,000 tons per year which the Germans attained shortly before the strategic bombers began to smash up their plants.


So lets avoid Synth Plants as much as possible

But lump Coal, isn't very efficient to store on vehicles, or to feed into the Boiler. So you can take the efficiency hit, and have a full time job of moving Coal into the Boiler.
This is fine for Civilian and Rear Area Army usage.

Buyt besides working the Coal thru Synthetic Plant, there is another way, but a bit more Technology than a Guy with a Shovel.

Grind it very finely, and add water.

Bingo- Coal Slurry. It can be pumped to a burner easily for Steam Engines
View attachment 720022

Coal Slurry looks like a poor Diesel, but the process is far simpler than hydrocracking Coal for Bergius process, that had pulverization as part of the process anyway.

I'm not saying Coal Slurry is awesome, but in areas where you don't need high speed diesels, you aren't wasting 4-8 tons of Coal to make one of Diesel of very pure nature(and you want some sulfur as to not wear out your mechanical injectors and pump)

Smoke is the sign of incomplete combustion, in Coal fired, or for that matter, Diesel applications. Coal slurry has much less problem in ash and incomplete combustion that solid Coal, so you gain back in efficiency what is lost in using water for the slurry

Now Actual Diesel Engines are more complex than a Boiler using a Coal Slurry Burner, in going thru mechanical injectors to each cylinder, and firing at the right moment, and the Slurry is more abrasive than 'Real' Diesel or Synthetic Diesel, so will be more wear.


Still could work for Trucks and Panzers.
The history of Aero-Diesel engines is not a happy one, so little relief for the Luftwaffe

There is a ray of sunshine in that cloud, Coal Slurry in Turbines. They already had low times before rebuild, so no change there

This is a move from the Coal Dust that they tried OTL to Slurry

USA during the Malaise Era coming out for other fuels, given the Shadow of the Arab Oil Embargo, did do research on Coal Slurry for vehicles stationary plants, and abandoned, as that threat receded.

Germany did spend years developing various such things, enabling for example many piston engine farm tractors to run on nearly anything that could burn, like wood etc. These
things were in production and were used. About half a million wood-burning converted vehicles were in use by about 1945. Apparently they could also run on
solid coal but I`m not sure how often that was actually done, I suspect not often as I would imagine most spare coal domestically would be used for cooking
and heating.

Stuff like Bismark was powered by pretty high performance oil fired boilers, so converting your navy probably isnt really a practical proposition, and you cant do it with aircraft
or higher performance vehicles like tanks. You`re left with agricultural vehicles and cars, many of which pretty much were converted to non-oil/fuel
product.

The cost of synthetic fuel is a bit of an irrelevance for Germany in war, and they have mountains of coal, so again
its not really a huge problem that you need lots of coal.

I`d just point out that crunching coal up and making it into a slurry is pretty much the first step of hydrogenation processing,
although you dont mix it with water, but oil. So you`re kindof doing the first step of processing there anyway for that side of things.

 

[z42]

They were using Horses, that was even more inefficient than Coal.

Indeed. It's easy to forget that the Blitzkrieg part of the army with tanks etc. was a small fraction of the total. The vast majority of the army moved by marching and horses for pulling equipment. I read somewhere the Germans were very surprised when the Allies landed in Normandy and they didn't bring vast amounts of horses with them; it was all mechanized.

However, a lot of German logistics was trains and river barges. Trains at the time were obviously steam, I'm not sure about river barges, did they use diesel engines already at the time, or steam?

Boilers and double acting cylinders like the Stanley Steamer or Sentinel Road Waggon, 9%

External Combustion just isn't that efficient. but is low tech, 1890s stuff.

Steam for road vehicles is just too bulky, I'm afraid. But a coal or wood powered gas generator is, I think, somewhat usable for civilian vehicles, and was indeed widely used.

Grind it very finely, and add water.

Bingo- Coal Slurry. It can be pumped to a burner easily for Steam Engines

Coal Slurry looks like a poor Diesel, but the process is far simpler than hydrocracking Coal for Bergius process, that had pulverization as part of the process anyway.

I'm not saying Coal Slurry is awesome, but in areas where you don't need high speed diesels, you aren't wasting 4-8 tons of Coal to make one of Diesel of very pure nature(and you want some sulfur as to not wear out your mechanical injectors and pump)

Smoke is the sign of incomplete combustion, in Coal fired, or for that matter, Diesel applications. Coal slurry has much less problem in ash and incomplete combustion that solid Coal, so you gain back in efficiency what is lost in using water for the slurry

Now Actual Diesel Engines are more complex than a Boiler using a Coal Slurry Burner, in going thru mechanical injectors to each cylinder, and firing at the right moment, and the Slurry is more abrasive than 'Real' Diesel or Synthetic Diesel, so will be more wear.

Still could work for Trucks and Panzers.
The history of Aero-Diesel engines is not a happy one, so little relief for the Luftwaffe

There is a ray of sunshine in that cloud, Coal Slurry in Turbines. They already had low times before rebuild, so no change there

This is a move from the Coal Dust that they tried OTL to Slurry

USA during the Malaise Era coming out for other fuels, given the Shadow of the Arab Oil Embargo, did do research on Coal Slurry for vehicles stationary plants, and abandoned, as that threat receded.

IIRC the US railroads did quite a lot of investigation into using coal dust and/or slurry for diesel locomotives. But turned out it's just too abrasive for diesel engines. I suspect it would be the same issue if you try to burn coal dust or slurry in a gas turbine.

Though I do wonder about coal dust that you mentioned, as did I in an earlier post in this thread. Obviously nothing for road vehicles, but what about ships? In ships the issue is historically a bit muddled as there were really three revolutions that happened more or less at the same time:

• Switching from coal to oil
• Switching from fire tube to water tube boilers
• Switching from (typically triple) expansion steam engines to turbines

So what if you keep the fire tube boilers and turbines, but instead of switching from lumps of coal handled by guys with shovels to oil, switch to pulverized coal combustion. Obviously coal has poorer energy density than fuel oil, and the handling, be it conveyor belts or shovels and wheelbarrows, and pulverizing equipment will take more space than simple fuel pumps. But still, the technology did exist at the time, and is today what is found in a coal power station.

 

[Engineman]

Outside of dragsters and such, I don't think methanol ever became much used in racing outside the USA?

Hi,
Methanol has been widely used in racing in the UK. However, it is limited in how many classes allow it. Speedway bikes (short dirt oval) and Sprint/Drag racing are/were the main users.

Eng

 

[ThomasP]

re Benzol, Benzene, Benzin, etc

I ran into some problems a while ago trying to sort out the different PN/Octane numbers for the different high percentage aromatic fuels, and this is some of what I have found re the terms/names Benzol, Benzole, Benzene, Benzin.

Although the racing industry sometimes used (pure) benzene in its racing fuels, the military aircraft fuel industry did not. When the terms Benzol/Benzole/Benzene/Benzin are used relative to military aircraft fuels they are referring to a mix of benzine/toluene/xylene. Additionally, xylene may be broken down into 3 groups - o-xylene, m-xylene, and p-xylene. (There are other very low proportions of other 'benzenes' present in the mix, but they usually amount to a total of only about 1-2%)

The following RON are from several modern sources (petroleum industry and scientific research) for fuel data, and they are consistent to within 1 or 2 points:

___________________________Freezing
______________RON________ Point
benzene______ 101 (pure)___ +42°F(+5.5°C)
toluene_______ 121 "_______ -139°F(-95°C)
o-xylene______120 "________ -13°F(-25°C)
m-xylene_____ 145 "________ -54°F(-48°C)
p-xylene______146 "________+56°F(+13°C)

The brand of fuel sold in the US in the 1920s and '30s called Motor Benzol was a 'natural' mix of benzene/toluene/xylene.

The brand of fuel sold in the UK in the 1920s and '30s called Benzole was primarily a mix of benzene and toluene (the majority of xylenes were removed from the mix for use in other industrial applications). Benzole was also mixed with gasoline in various blends.

Benzene and/or Benzol in some languages are specific to pure benzene, and are used in the scientific fields as such. But over the years, depending on which industry and/or country, the terms Benzol/Benzole/Benzin/etal may also be used to refer to any of several motor fuels containing a blend of the 'benzenes'.

When the British were referring to Benzene or Benzenes in their aromatic blends of aviation gasolines they were referring to a mix of benzene/toluene/xylene. These 'benzenes' were mixed with gasoline along with other compounds to arrive at the various Octane ratings.

The proportions of the different 'benzenes' in the blend, along with whatever other chemistry (TEL for example) was used in the fuel, determined the effective RON values of the aromatic blends.

While the freezing temperature of (pure) benzene was relatively high at +42°F(+5.5°C), the freezing point of toluene -139°F(-95°C) rendered the freezing problem of pure benzene moot. The xylenes varied from +56°F(+13°C) for p-xylene to -54°F(-48°C) for m-xylene. The effective freezing points of blends used for anything other than racing were such that the normal blends used had no particular problems at high altitudes.

Hopefully this info is useful in some way?

 

[Shortround6]

• Switching from coal to oil
• Switching from fire tube to water tube boilers
• Switching from (typically triple) expansion steam engines to turbines

In the 1920s-30s there was a huge improvement in boilers. The ability to make power (steam) increased several fold for the same tonnage of boilers and the same foot print (square footage of boiler room)

The change from fire tube to water tube took place in the 1890s. the change from reciprocating to turbines took place from 1900 (ok 1897) through the early 19 teens. Oil came in the mid teens.

Using very large boilers that could be fired by oil sprays instead of how far a man could throw coal with a shovel took a while. Geared turbines also took a while. Running turbines at the same speed the propellers were turning meant very large/heavy turbines.


Now for road vehicles steam does have a few advantages.
You don't need a transmission, or at least not much of one. The reciprocating steam engine is reversible. It also makes maximum torque at stall so getting a heavy load started is rather easy. The road vehicles shifted to a water tube boiler in the 1920s. They did need liquid fuel to keep the boiler compact and for easy start up.

 

[ThomasP]

A bit of info on alcohol based ICE fuels used in the early-1900s to mid-1930s.

Albizol_________ethanol/benzol (ethanol specifically from potatoes)
Monopolin_____ ethanol/gasoline, ≤25/≥75, 56-70 RON (ethanol specifically from potatoes)
Discol_________ ethanol/gasoline/benzol
Hector Fuel____ cyclohexane/benzol 70/30 (not alcohol based but interesting for comparison)
Alcogas________ethanol/gasoline/benzol/other 40/35/17/8
Power Alcohol__ethanol, 109 RON
Methanol______ methanol, 109 RON

Albizol and Monopolin were of German origin. Discol was British in origin (I think). Hector Fuel and Alcogas were US in origin. Power Alcohol was a term used in various countries when referring to bio-alcohol/ethanol for use as a motor fuel, and became available in Australia in the late-1920s.

When I looked up Albizol I was surprised at how many hits I got for model railroad tank cars.

 

[Daggerr]

re Benzol, Benzene, Benzin, etc

...................... When the terms Benzol/Benzole/Benzene/Benzin are used relative to military aircraft fuels they are referring to a mix of benzine/toluene/xylene.

......................

Benzene and/or Benzol in some languages are specific to pure benzene, and are used in the scientific fields as such. But over the years, depending on which industry and/or country, the terms Benzol/Benzole/Benzin/etal may also be used to refer to any of several motor fuels containing a blend of the 'benzenes'.

.....................

The German word Benzin strictly speaking means gasoline, not benzene.

In German language benzene is called Benzol and toluene is called Toluol. However Benzol can also refer to a coal tar or other product rich in aromatics (benzene, toluene, xylene).

It easily gets confusing when the word benzol or benzin is used in a text. What the author really meant can often only be deduced from the context.

Not sure if benzol really is pure benzene. Per the previously cited wiki page, it seems it was a trade name for a product produced from coal tar. So probably some kind of liquid containing mostly aromatics, of which likely a fairly high fraction was benzene.

Anyway, current automotive gas regulations typically limits benzene to < 1% due to the toxicity & cancer issue. Aromatics in general, while perhaps a bit offensive to current sensibilities wanting a clean-burning fuel (aromatics tend to produce quite a lot of soot), constitute about 20% of typical auto gas. In current 100LL aviation gasoline I understand toluene is the major aromatic fraction, and it has more aromatics than automotive gas due to the good rich octane rating. Non-benzene aromatics like toluene, (some isomers of) xylenes, and ethylbenzene also have somewhat more agreeable melting points.

In the EU auto gas has a 35 v% limit on total aromatics and a 1 v% limit on benzene. No lead (TEL) allowed.

Today's 100LL aviation gasoline specification ASTM D910 allows some lead and has no limit on max aromatics or benzene content, although other specs (vaporization and freezing point) will be a limiting factor for aromatics content. Surprisingly there is no limit on carcinogenic benzene.

During WW2 nobody cared about limiting lead, aromatics or benzene in gasoline for health reasons.

 

[z42]

The German word Benzin strictly speaking means gasoline, not benzene.

Yes, similarly in many languages, with some slight variation in spelling. So we're running our cars on 'benzin' containing at most 1% benzene.

In German language benzene is called Benzol and toluene is called Toluol.

Over here we have a popular brand of household cleaning agents called 'Tolu', which I'm quite sure doesn't contain any toluene.

Today's 100LL aviation gasoline specification ASTM D910 allows some lead and has no limit on max aromatics or benzene content, although other specs (vaporization and freezing point) will be a limiting factor for aromatics content. Surprisingly there is no limit on carcinogenic benzene.

Wouldn't surprise me if D910 is old enough that at the time there was no benzene limit in automotive gas regulations either.

 

[tomo pauk]

The cost of synthetic fuel is a bit of an irrelevance for Germany in war, and they have mountains of coal, so again
its not really a huge problem that you need lots of coal.

Coal was as 'free' in Germany as possible. What was costly - in money, materials and manpower used to make - were the synthetic fuel factories.
Trick with coal is that one can use locally-sourced coal to power the coal-powered vehicles (doh), that can come in handy for logistical units away from Germany, like beyond Warsaw, in France, or Yugoslavia.

 

[Shortround6]

Today's 100LL aviation gasoline specification ASTM D910 allows some lead and has no limit on max aromatics or benzene content, although other specs (vaporization and freezing point) will be a limiting factor for aromatics content.

Another limit was the BTU content of the fuel specification.
Pure gasoline was about 19,000 BTUs per pound. Aviation fuel (at least British and American fuel) was 18,700-18,800 BTUs per pound.
There are a bunch of aromatics but some of the common ones, like benzene and toluene have 17,300-17,400 BTUs per pound.
Some are better than gasoline.
Some respond better to lead.
Some are much more expensive to manufacture than others.
Some are more important than others in time of war. Toluene was a very large part of TriNitroToluene.

A lot of the alternative fuels can be used for ground transport.

The importance of lead cannot be underestimated though. Just 1 cc of lead was enough to raise straight run gasoline from PN 40 to PN 73. This made the production of motor fuel (car/truck) very cheap and easy from low grade gasoline.
The allied change from 4cc per gallon to 4.6 cc per gallon increased production of 100/130 by over 20% from the same feed stocks.

 

[thunderbird]

Not sure why anyone is looking for ways to improve Germany's outcome in WWII. just saying

 

[MIflyer]

Depends on what you call "High octane".

The C-85 engine in my Ercoupe was certified to run on 73 Octane. Despite that, there are people who do not want to use auto fuel in those engines and now you can't even find alcohol-free auto fuel that is less than 92 octane. 87 octane was "high octane" in 1940 and in fact the reason the DC-4 uses the R-2000 version of the R-1830 was because the airlines wanted to be assured that they would still get the same performance if they were forced to refuel at a field that only had the lower octane gasoline. When they were ferrying a Ju88 back to the US from N Africa they equipped it with some P-38 drop tanks and were assured that lower octane fuel was available at Ascension Island - but it was not. They were forced to use 100 octane fuel and almost did not make it the rest of the way across the Atlantic as a result.

 

[marathag]

Steam for road vehicles is just too bulky, I'm afraid. But a coal or wood powered gas generator is, I think, somewhat usable for civilian vehicles, and was indeed widely used.

Not that bad

Sentinel Semi. Hook up the trailer and go.
for Off-Road work

Both 1920s. Vertical boiler. 6 ton drawbar loads typically wasn't a problem. 30mph top speed, as limited by law, not capability of it's Steam 124HP plant.

Steam HP and Gasoline HP doesn't exactly translate.

WoodGas conversions allowed existing Gasoline IC Engines to keep functioning, at lower HP ratings. Not so good for heavy goods transportation

 

[marathag]

IIRC the US railroads did quite a lot of investigation into using coal dust and/or slurry for diesel locomotives. But turned out it's just too abrasive for diesel engines. I suspect it would be the same issue if you try to burn coal dust or slurry in a gas turbine.

Both Dust and Slurry were looked into. But with the embargo a thing of the past, not needed.

The Turbines, they were short life from the combustion section already, the issues introduced by the slurry wouldn't worsen that

 

[Deleted member 68059]

This helps provide some perspective:

(SOURCE: The Petroleum Handbook, SHELL, 1957, obviously my EXCEL)

 

[z42]

I stumbled on an article about diesel tanks in WWII Germany. It seems that there was an understanding of the benefits of diesel power, but Maybach had managed to get into more or less a monopoly position with their gasoline tank engines and fought hard to retain it, ultimately succeeding despite a series of suitable diesel engines being developed and tested in tanks. Various myths were promulgated such as, it was only possible to produce synthetic gasoline, not diesel (it wasn't ), or that the Navy was already using up the entire diesel fuel supply (also not true).

How the Wehrmacht's Diesel Stalled

A blog about World War II era archive documents, primarily dealing with armoured warfare.

www.tankarchives.ca

 

[33k in the air]

This helps provide some perspective:

(SOURCE: The Petroleum Handbook, SHELL, 1957, obviously my EXCEL)
View attachment 720274

The book Oil & War — How the Deadly Struggle for Fuel in World War II Meant Victory or Defeat by Robert Goralski and Russell W. Freeburg (first edition, William Morrow and Company, 1987; reprint, Marine Corps University Press, 2021) is an in-depth examination of the matter of oil during the war.

It can be downloaded for free from the Marine Corps University website.

 

[Deleted member 68059]

The book Oil & War — How the Deadly Struggle for Fuel in World War II Meant Victory or Defeat by Robert Goralski and Russell W. Freeburg (first edition, William Morrow and Company, 1987; reprint, Marine Corps University Press, 2021) is an in-depth examination of the matter of oil during the war.

It can be downloaded for free from the Marine Corps University website.

"Billingham was also built to produce high-quality fuel through hydrogenation identical to the German oil-from-coal process. While the British initially rejected this process as economically impractical and strategically undesirable, the Billingham project was a hedge against import uncertainties. In the end, Billingham produced no synthetic fuel." (pg69)

Hmmmm... didnt do the British research quite as well as might be expected.