Coal-fired merchant shipping?

In the 19th century, most ocean shipping was powered by coal/steam and wind. There was a well distributed system of coaling stations and ports worldwide. This was gradually switched over to oil. Today, there may be a strong rationale for going back to coal. Many ports are set up to load up ships with coal for export anyway, and material handling systems for coal have become very automated and advanced. Ease of handling was one of the big reasons for switching from coal to oil, but the advantage of oil in this regard is not as great as it was when coal had to be shoveled by hand. The price of oil has gone up dramatically lately, and shows no sign of going down much soon. Coal prices are lower and more stable by comparison. For energy security, coal has the advantage hands down for western nations. Comments?-Jitney

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Low thermal efficiency, means lots of coal, conversion of ships to steam plants and coal bunkers won't be easy nor cheap. Won't happen. About as likely as the railroads going back to steam engines (albeit much modernized steam engines).

Might happen: conversion of coal to diesel-compatible liquid fuel.

Are there economical conversion processes out there, is it being done at all?


Reply to
Damon Hill

If you want to use coal, then the obvious way is to use pulverised coal firing, to provide steam for turbines.

You then need coal bunkers with automatic extraction, pulversisng mills and the appropriate air handling system to the burners. You will also need some means of intercepting and handling the ash produced, and of disposing of it when re-bunkering. Storing the coal in pulverised form is not a good thing, because of the fire hazard.

Technically it's possible. An alternative is to gasify the coal and then use a gas turbine.

Reply to
Terry Harper

Where will you find voluntary slaves to go mining?

Who is again prepared to pay compensation for anthraco-silicosis and widows?

Where will you dump the huge new heaps of refuses in our legal evironment?



Reply to
jacques jedwab

Possibly automation and advanced coal handling would have improved however consider that:

1 Fischer-Tropsch synthesis of coal to diesel is now 60% efficient. 2 Low speed 2 stroke marine diesels are up to 55% efficient. This overall efficiency of about 30%-33% is about what could be produced by a steam engine. That is about what is normal for a steam engine. Potentially the finest large scale superheated steam power plants could achieve 44% efficiency but I can't see that being achieved in a shipboard installation.

Note that Fischer-Tropsch is excellent at synthesising diesel (diesel is long linear chains and easier to make than isomers such as iso-octane) and that FT diesel is also completely clean and sulphur free far superior to petroleum derieved fuel.

Note also that coal and heavy bunker oil is responsible for heavy metals pollution (eg Cadmium and Mercury) mainly from exhausts (but also colliery washeries).

Maybe some of the techniques such as refining coal and converting it to consistent briketts or granules suitable for handling, blowing etc might be an approach.

As an alternative to steam consider some other engine types: in the

1920s to 1930s the Germans ran constant volume gas turbines developed by the engineer Holzwarth that ran of powdered coal. Potentially more practical is the closed cycle gas turbines can directly run of coal as the turbine disk is not exposed to combustion.

Personally the Synthesis approach seems the most compelling to me.

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Very unlikely that synthesized fuel would ever become cheaper than the residue that they sell as Heavy Fuel Oil, which would be called chemical wastage if they couldn't power ships with it.


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Reply to
Timo de Beer

There are lots of unemployed coal miners who would gladly collect the none-too-shabby wages paid to miners. There are even other unemployed people who would also go down the shafts for that level of wage, myself among them.

With the proper personal protective equipment, brown lung is not a danger, so there is no need to compensate. With tele-operated mine equipment, even cave ins are less than a disaster.

About time you came up with an actual problem.

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Richard Bell

I agree with previous posters that a coal-derived liquid fuel seems far more likely than direct use of coal aboard ships.

My impression that the traditional powerplant consisting of a boiler and steam turbine has largely been replaced by diesel engines or gas turbines in newer ships.

Even if the ship has a boiler, coal contains much more unburnable mineral matter (slag/ash) than does oil. This affects the design of the boiler.

Regarding jacques jedwab's question about where are we going to find people to mine the coal, etc., coal is extensively used in the U.S. (annual production roughly 1 billion tons per year), mostly for electrical power generation.

Olin Perry Norton

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Olin Perry Norton

Damon Hill a utilisé son clavier pour dire :

Yes, in South Africa Sasol produce 165 000 barrels per day of synthetic fuel, using fischer-Tropsh process. Most of it is made from coal, and some from natural gas - most people believe south africa has no hydrocarbons, in fact they do have a bunch of small offshore fields (mostly gas, some oil too).

It theory, any kind of fuel made of carbon of hydrogen could be used. Of course, only a fool would use a fuel that is not much cheaper on a per megajoule basis than crude oil.

During aparatheid area, this was developped because South Africa wanted to have indigenous liquid fuels. Coal is difficiult to exctract in south africa (no surface mining, coal seems are deep) but apartheid meant they had a extremely low cost workforce for their mines.

Now with oil at 50$, the process must be quite competitive, even with more expensive coal.

But even if it is competitive for cars, it may not be for merchant ships. Cars use distillated fuels, like gasoline or diesel. Ships use residual fuel oil, a low-grade fuel that is probably cheaper than crude oil itself.

Synthetic fuels work, but they are quite wasteful. Only 55 to 60% of the primary energy (the calorific value of coal, gas, petcoke, or anything else used as feedstock) is recovered in the resulting liquid fuel. Efficiency can be improved a little if waste heat and tail gas are used.

If the primary fuel is coal, CO2 emissions on a full cycle basis are awfull.

-- "We do not consider that aeroplanes will be of any possible use for war purposes" Richard Haldane, ministre à la guerre brittanique, 1910

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A friend just visited a couple of surface mines in South Africa. They were using large draglines to collect the coal. They were toward the east of Pretoria about 100 km.

It's interesting that they don't seem to be expanding the Sasol plant, even though most of their liquid fuel is imported, at least I haven't seen any announcements.

As traditional crude oil gets more scarce, it wouldn't surprise me to see countries with large coal supplies, like China, Russia, the US, and South Africa shift to more synthetic fuel. The opportunity to get indigenous fuel at lower cost would be too tempting to ignore.

Reply to
James Robinson

Ok, i'm wrong, i checked in fact a part of their coal is produced from open pit mining.

That's right. However, sasol is exporting its technology : the group is involved in a Gas-To-Liquid (GTL) project in Qatar. They don't seem to expand theiur coal-to-liquids capacity. And their Gas-To-liquid project (Mossgas) in running out of reserves, the fields in mosselbay from which it take its feestock is almost depleted, they are trying to connect new, further (perharps in mozambique!) natural gas reserves to it.

In the short term, natural gas may be the preferred feedstock where it is available. It is easier to convert into syngas, make less CO2 and is cheaper to extract from the ground. Also, it doesn't left you with tons of ash and sulfur.

Gas, because it's expensive to transport from one continent to another, is not as "globalized" as oil. It can be scarse somewhere and abondant elsewhere.

Countries like bolivia, australia, egypt, argentina, indonesia, malaysia have a oil production that is insuffisant to meet their needs and/or in decline, but they have quite a lot of gas.

So they began by using oil instead of gas for big stationnary need : electric plants, cement kiln, hydrogen production in refineries, and so on. but their is not much left to do. Most of these consumers HAVE shifted to gas. GTL may be a solution to go further.

-- "We do not consider that aeroplanes will be of any possible use for war purposes" Richard Haldane, ministre à la guerre brittanique, 1910

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Not impossible, but doubtful. It would rob precious cargo space. I think simple, low maintenance, nuclear reactors with a discardable fuel cartridge would be more interesting. The power to weight ratio required is low. Then there is wind, or synthetic oil if you like oil that much.

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Surely coal has an advantage over oil if the ship sinks too ? Solid lumps of coal staying in the hulk and/or lying on the bottom would be less destructive than an oil slick floating on the top, wouldn't it ?


------------------------------------- The power of accurate observation is commonly called cynicism by those who have not got it.

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Reply to
Bruce Sinclair

Liquid is not nessary propane and butane are good enough they are nearly twice as good for motor fuel as gasoline on pound for pond basis. Being under 200 to 300 PSI is a PITA but it not any worse than any other plan and it has a 70 year history

Gordon Couger Stillwater, OK

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Gordon Couger

Thanks for the (usually) good input. The synthetic fuel route may develop on its own if economics permit. The key to overcoming the volume/energy ratio, I believe, is the placement of coaling stations at coastal facilities. Some of these already exist for the purpose of exporting large amounts of coal to consuming nations, and could be adapted to the purpose of refueling pretty easily. Modern material handling technology has overcome the problems associated with loading coal that spurred the switch to oil on ships in the early 1900's. The problem of coal ash is a real one, fly ash removal systems were set up at power plants because of air quality issues. The composition of fly ash is remarkably similar to cement powder, and a significant amount is blended into concrete. The rest is landfilled, having been designated by the US EPA as non-toxic solid waste. Perhaps it could be solidified into large concrete blocks and dropped into the sea?-Jitney

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Four coal fired bulk carriers have been sailing the coast of Australia for the past 25 years.

River Boyne, River Embley, Endeavour River and Fitzroy River all about

85,000 tonnes have been trading between Gladstone and Weipa in the bauxite trade for the past 25 years. Two vessels have twin boilers and the other two single boiler installations fired by mechanical stokers (detroit stokers) using nugget coal.

These ships are managed by ASP Ship Management

Good operation is dependant on coal quality and the variable coal quality in diffrent ports around the world from calorific content, ash content and swell factors have marked results in performance.


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Ian Rogers

Ian Rogers schrieb:

what happened here - I find only a repost?

seed oil may have similar problems but smaller I do expect.


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Reply to
doug roberts

I think accumulation of ash would be an insurmountable problem in such a system. In a large ship, a steam turbine fed by a coal-fired boiler might be best. Whether direct drive or though an electric, I leave to the mechanical engineers.-Jitney

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