Cotton Mill Steam Engine Coal Usage

[Andy873]

By the early 1960's many of Lancashire's cotton mills were closing at a rate of about 1 a week.

These mills were powered by static steam engines, many running 6 days a week - the question is how much coal would one of these engines use say in a week? I'm trying to determine how much coal traffic would have been lost along my old branch line around this time due to these mills closing down or changing over to electricity.

This one was one of the last in Burnley. I'm told it was a 450 hp cross compound engine, with 150 psi. It powered 600 looms.

Thanks,
Andy.

 

[Gloster]

I suspect there are just too many variables to make anything but the vaguest estimates. Different boilers, different practices, some mills converting to other means (oil?) or using water power, etc. And of course there was a massive amount of domestic coal and there would have been other industrial users. Middleton Press books normally included tonnage figures for two years in the 1920s and 1930s, so they would have been publicly available then; I am not sure if Middleton have got that far north (yet). BR would obviously have had some figures, but I don’t know where they would be available: closure minutes?

 

[Andy873]

I suspect there are just too many variables to make anything but the vaguest estimates. Different boilers, different practices, some mills converting to other means (oil?) or using water power, etc. And of course there was a massive amount of domestic coal and there would have been other industrial users. Middleton Press books normally included tonnage figures for two years in the 1920s and 1930s, so they would have been publicly available then; I am not sure if Middleton have got that far north (yet). BR would obviously have had some figures, but I don’t know where they would be available: closure minutes?

That's the thing, the closure minutes (1964) for the line don't mention any mills specifically, just a list of coal merchants.

 

[30907]

That's the thing, the closure minutes (1964) for the line don't mention any mills specifically, just a list of coal merchants.

I wonder how many mills were still receiving coal by rail then, given that
(1) mills were closing and being repurposed (Oxo, Metflex....) well before WW2 - they may then have used coal for heating though
(2) local pits were close by but not on a direct rail route.

Possibly this is one for a cotton industry forum?

 

[zwk500]

That's the thing, the closure minutes (1964) for the line don't mention any mills specifically, just a list of coal merchants.

If the mills were using the Coal merchants to manage their supplies rather than dealing with the railway directly, then they wouldn't be listed specifically.
I don't know if this was the case, and if these merchant's records would still be preserved anywhere. But you may be able to find books on the cotton industry which contain comparable figures.

 

[billh]

Many cotton mills were built next to navigable waterways such as the Leeds & Liverpool canal, the canal provided water for the boilers and a very convenient supply of coal from the Lancashire pits to the mills' boilerhouses.
In the 1960s there were still some mills receiving coal by water but there was an on going last ditch attempt to modernize their machinery to electric power and the use of stationary steam power faded.
A very few mills had their own railway sidings where coal could be delivered but mostly coal delivered from remote railway sidings to mills by road, motor lorry by that time sometimes direct from the colliery, not necessarily the nearest, it
depended on the type of coal preferred for the boilers. I remember one Burnley mill where the coal used to arrive by canal boat but that traffic had finished and from then on two boats were moored next to the mill and used as bunkers for road delivered coal!
I visited the part preserved Queen St Mill a few years ago and was told that the coal stock in the boiler house was their last delivery from Kellingley Colliery (closed 2015), was it burnt or put in a glass case?

 

[RUFJAN15]

As Gloster has suggested there are many variables and it is only possible to make an 'order of magnitude' estimate.

If we start with the 450hp engine, this is equivalent to 336kW of mechanical power, so it would seem reasonable to assume that it operated with an average output of 250-300kW. To estimate the energy going into the boiler we need to know the efficiency, and this is largely dependent on the steam conditions (temperature/pressure of the steam entering the engine compared with temperature/pressure of the exhaust steam). As the quoted engine operated at 150 psi, similar to a railway locomotive, we can hazard a guess that it's efficiency was similar. The typical efficiency quoted for a steam locomotive is 10%, so the boiler of the mill engine would require to generate 2500 - 3000kW of thermal power to support the mechanical output.

The next step is to estimate the weight of coal that would need to be burnt per hour to generate 2500-3000 kW hours of energy (9,000 - 11,000 MegaJoules [MJ]). This has to be an even wilder guess as the calorific value of coal can be very variable, but 25MJ/kg is a typical value for thermal coal, so that gives us a coal burn of 400 kg per hour or around 10 metric tonnes/day if operating continuously.

The answer to your question would appear to be 1x 10 ton wagon load of coal per day for a 450 hp engine operating continuously.

It is more than 40 years since my very brief placement in a power station efficiency department, so I may have missed something. However, the numbers do seem to make sense.

 

[Andy873]

As Gloster has suggested there are many variables and it is only possible to make an 'order of magnitude' estimate.

If we start with the 450hp engine, this is equivalent to 336kW of mechanical power, so it would seem reasonable to assume that it operated with an average output of 250-300kW. To estimate the energy going into the boiler we need to know the efficiency, and this is largely dependent on the steam conditions (temperature/pressure of the steam entering the engine compared with temperature/pressure of the exhaust steam). As the quoted engine operated at 150 psi, similar to a railway locomotive, we can hazard a guess that it's efficiency was similar. The typical efficiency quoted for a steam locomotive is 10%, so the boiler of the mill engine would require to generate 2500 - 3000kW of thermal power to support the mechanical output.

The next step is to estimate the weight of coal that would need to be burnt per hour to generate 2500-3000 kW hours of energy (9,000 - 11,000 MegaJoules [MJ]). This has to be an even wilder guess as the calorific value of coal can be very variable, but 25MJ/kg is a typical value for thermal coal, so that gives us a coal burn of 400 kg per hour or around 10 metric tonnes/day if operating continuously.

The answer to your question would appear to be 1x 10 ton wagon load of coal per day for a 450 hp engine operating continuously.

It is more than 40 years since my very brief placement in a power station efficiency department, so I may have missed something. However, the numbers do seem to make sense.

Thanks for the detailed reply, very helpful. The best we can say is these engines used a fair amount of coal, and this was just one engine. The two towns on the branch line each had (in 1912) 19 mills each, and another 6 within striking distance in other words 44 mills along the line.

 

[RUFJAN15]

Thanks for the detailed reply, very helpful. The best we can say is these engines used a fair amount of coal, and this was just one engine. The two towns on the branch line each had (in 1912) 19 mills each, and another 6 within striking distance in other words 44 mills along the line.

A lot of coal, yes, but nothing compared with the big power stations!

A CEGB 2000MW coal fired station, although much more efficient than the mill engines, would still need to produce around 6000MW (6,000,000 kW) of thermal power to deliver 2000MW of electrical power to the Grid. That's 2000 times the thermal power going into the mill boiler, so rather than 400kg/h the coal burn would be around 800 tonnes/hour at full output.

You can understand why development of the merry-go-round coal delivery system went hand-in-hand with introduction of the new generation of power stations.

 

[Lloyds siding]

This is the sort of question that could easily have been answered, just a few years ago, by visiting the reference section of Burnley library (the books would have been there because there was a local professional interest in boiler efficiency,etc.). There's certainly books out there....I did have a book giving calorific values of coal from each of Britain's coal mines.
The boilerman at Queen St mill may be able to provide some information on throughput of coal. I had quite a long chat to him when I visited, and got to feed the firebox as a result; he asked if I'd done it before, and I said yes, at my school...when I was a schoolboy.
But you've got some good guestimates above.

 

[rototunablack5]

I have a book called “Manufacturing the Cloth of the World” by Roger N Holden and it tells me (page 147) that there are few figures available for coal consumption. However it cites Bancroft Mill in Barnoldswick which used (in the 1970s) 10 tons of coal in summer and 35 tons in winter to include heating. The cross compound engine was rated at 500hp.

This backs up one of the previous posts about 1 x 10 ton wagon load of coal per day for a 450hp engine.

One final stat from my book for you Andy, in 1911, Great Harwood had 14,534 weaving looms and Padiham had 14,221. Burnley had 98,923. Figures taken from Worrall’s Lancashire Textile Directory

 

[randyrippley]

As Gloster has suggested there are many variables and it is only possible to make an 'order of magnitude' estimate.

If we start with the 450hp engine, this is equivalent to 336kW of mechanical power, so it would seem reasonable to assume that it operated with an average output of 250-300kW. To estimate the energy going into the boiler we need to know the efficiency, and this is largely dependent on the steam conditions (temperature/pressure of the steam entering the engine compared with temperature/pressure of the exhaust steam). As the quoted engine operated at 150 psi, similar to a railway locomotive, we can hazard a guess that it's efficiency was similar. The typical efficiency quoted for a steam locomotive is 10%, so the boiler of the mill engine would require to generate 2500 - 3000kW of thermal power to support the mechanical output.

The next step is to estimate the weight of coal that would need to be burnt per hour to generate 2500-3000 kW hours of energy (9,000 - 11,000 MegaJoules [MJ]). This has to be an even wilder guess as the calorific value of coal can be very variable, but 25MJ/kg is a typical value for thermal coal, so that gives us a coal burn of 400 kg per hour or around 10 metric tonnes/day if operating continuously.

The answer to your question would appear to be 1x 10 ton wagon load of coal per day for a 450 hp engine operating continuously.

It is more than 40 years since my very brief placement in a power station efficiency department, so I may have missed something. However, the numbers do seem to make sense.

Don't forget that most cotton mills would have been using Lancashire boilers, much lower pressure and lower efficiency than a locomotive firetube boiler.

 

[Andy873]

I have a book called “Manufacturing the Cloth of the World” by Roger N Holden and it tells me (page 147) that there are few figures available for coal consumption. However it cites Bancroft Mill in Barnoldswick which used (in the 1970s) 10 tons of coal in summer and 35 tons in winter to include heating. The cross compound engine was rated at 500hp.

This backs up one of the previous posts about 1 x 10 ton wagon load of coal per day for a 450hp engine.

One final stat from my book for you Andy, in 1911, Great Harwood had 14,534 weaving looms and Padiham had 14,221. Burnley had 98,923. Figures taken from Worrall’s Lancashire Textile Directory

Very interesting facts here, even the two smaller towns of Great Harwood & Padiham in 1911 had lots of weaving looms, get to a bigger town like burnley and the number jumps right up. Thank you for those great facts!

Don't forget that most cotton mills would have been using Lancashire boilers, much lower pressure and lower efficiency than a locomotive firetube boiler.

Yes, it's a fair point, 10 ton of coal per day (per mill) is probably about the best estimate we can get to, but it's also fair to say that the mills all needed quite a bit of coal delivering (no matter how much per day).

Thanks everyone,
Andy.