Hoppers
Originally Posted by ansoni
I am working on 350MW TPP. I wanted to know that what are the considerations for designing Track Hopper Capacity for BOBR Wagons. What is the thumb rule for the same?
Regards,
Amit Soni
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The isssues include:
Available coal quality
What is the available budget versus actual costing.
What is the time frame for construction after signing the contracts?
Errors and omissions clauses.
The plant siting details including:
Where are the water intake and discharge lines in relation to the unloading system?
Available land for the unloading system.
how adequate is the drainage ?
How many cars are to be unloaded at one time?
Will the unloading site have an unloading loop for one continuos rake of cars or
will each car be moved individually and unloaded?
How much room for full rakes of cars?
How much room for empty rakes of cars?
Are empty cars to be stored on empty car sidings for later removal or unloaded and returned to the railroad company
the same day?
Will fill be needed to stabilise it?, how deep are the foundations for the trestles going to to be and will we need sheet piling to anchor and pour the concrete for the foundations of each trestle? will concrete ties be used and imbedded in concrete for in plant rail lines?
b is the coal removed by rubber tired loader, dozer or a plow conveyor to the takeaway conveyor from under the trestle?
c. how is the stuck coal going to be removed from the cars?
d. how far from the coal stock pile to the coal bunkers above the boilers and how is the coal to be delivered.
2. How big is the stock pile going to be on a daily basis?
a. How often can coal be delivered?
b. what amount of coal can be stock piled for buffer capacity?, typically being 90 days at a minimum to have carry over coal stocks in case of labor strikes and disasters due to weather, earthquakes, typhoons etc.
c. Water supply for fire fighting and dust suppression.
d. rail guage
e. labor force.
f. available railroad engines to be if any or if an automated car moving system is to be used to move rakes of cars.
What provisions are in place if any for any unforseen circumstances/liabilities/land disputes? ■
Track Hopper Capacity
Open hopper car with rapid (pneumatic) bottom discharge doors, air-braked. BOBRN and BOBR (see above) are most often used for carrying coal to thermal power plants, and also for ore, stone, track ballast, etc. Each wagon holds some 60t of coal loaded from the top and unloaded from the bottom by means of the pneumatically operated doors. The contents of the wagon can be discharged completely in about 15 seconds.
The door-opening mechanism is triggered by lineside devices running on a 24V or 32V DC source. As the wagons in a rake pass by the triggering devices, their doors open and their contents are unloaded into the pits below the tracks (the 'merry-go-round' system). The versions used by the power plants have 12 bottom doors, whereas IR uses variants that have 8 doors.
* Tare: 25.6t
* Payload: 55.68t, 57.2m3
* Length over headstock: 9.671m
* Height: 3.735m
* Width: 3.5m
* Distance between bogie centres: 6.79m
Length over coupler faces 11.6m. AAR 'E' high-tensile coupler with high-capacity draft gear. CASNUB 22 NLB cast steel bogies. Air brakes and parking brakes. Rated at 100km/h. (Power plant versions without air brakes are rated at a lower speed.)
Some BOBRN wagons have been made of aluminium (BOBRAL / BOBR-AL). In these, the underframe is made of steel while the rest of the body is made of aluminium. The maximum axle load is the same as that of the regular BOBRN (20.32t), but the tare weight is reduced by 3.2t and the payload correspondingly increased by the same amount. The aluminium alloy used is 'RDE-40', and has 4% zinc, 2% magnesium, 0.35% manganese, and 0.15% zirconium.
I think you are referring to these wagons.
You are required to unload a rake carrying 3000 T of coal in about three hours.
You may need a track hopper with length for accommodating five wagons. Width of the hopper will we wider than Broad gauge used in India Railways. Side slope will be 55 to 60%. A conveyor rated at about 1500 TPY to take away material from the track hopper.
IRCON may help you in designing a system.
A pic of wagon is attached.
Attachments
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A Black Art
Originally Posted by ansoniI am working on 350MW TPP. I wanted to know that what are the considerations for designing Track Hopper Capacity for BOBR Wagons. What is the thumb rule for the same?
Regards,
Amit Soni
Coal consumption is approximately 0.5kg per kWh. 
That'll get you started until the boffins chip in. ■
Track Hopper Capacity
I do not know linkage for 350 MW power plant being set up. If it is using Indian coal with calorific value of about 3500 and ash content of around 35%, lot of care is required in designing the coal and ash handling systems in the plant. ■
Re: Track Hopper Capacity
Sir,
I thank you so much for the reply.
I have some more informations about our Plant.
Actually, this is a pit head plant. Coal Mines are nearby say105 Kms.
The Railway has confirmed to deliver 118 Wagons (2 Rakes) each of 64 Tonnes of weight.
Our stock pile Storage is about 40days.
The belt Carrying capacity is about 550TPH. There are 2 belts below Track Hopper.
Coal is 100% indeginious with 3300 GCV
Please guide me in Deciding Track Hopper length. ■
Track Hopper
In your case rake is 60 wagons each wagon carries 64 T. The rake is carrying 3840T of coal. If you are unloading coal while in motion (at a creep speed) and wagon gets empty in 20 seconds (Railways have designed for 15 sec). You will need a track hopper length equal to the travel distance in 30 seconds. The trigger will open gates of each wagon as it enters track hopper zone.
The conveyor capacity will have to match the rate at which wagons are being unloaded. ■
India Coal
Originally Posted by ansoniI thank you so much for the reply.
I have some more informations about our Plant.
Actually, this is a pit head plant. Coal Mines are nearby say105 Kms.
The Railway has confirmed to deliver 118 Wagons (2 Rakes) each of 64 Tonnes of weight.
Our stock pile Storage is about 40days.
The belt Carrying capacity is about 550TPH. There are 2 belts below Track Hopper.
Coal is 100% indeginious with 3300 GCV
Please guide me in Deciding Track Hopper length.
Greetings and salutations A. N. Soni,
If this is a mine mouth power station why are you using rail to begin with?
Are you using an inner and outer loop sets of tracks with passing branch switches for the full and empty rakes of cars.
Please tell us more
lzaharis
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Re: Track Hopper Capacity
Dear Mr Izaharis,
Greetings!!
Actually in india 105 Kms, you may not call it as Pit Head. Sorry using this word 'Pit Head' in my question earlier.
And it is not our own plant. Our Client has done much exercise on all the parameters like economy and finally they kept this provision.
However, sir, I also wanted to know that what would be the speed of train while it will pass over the track hopper? ■
Re: Track Hopper Capacity
Dear Shri Amit Soni,
The other respondents have already given extensive information. I would like to add only one consideration.
Firstly, one has to see whether the wagons are to be unloaded while in slow motion, automatically. In this case the entire rake of wagons gets unloaded quickly and leaves the track hopper for next trip. So, in such arrangement, accommodation of the coal content of the entire rake into the hopper is one of the primary consideration for deciding the hopper capacity.
The track hopper arrangement is also used for unloading coal when wagons are being stationary positioned for unloading. In this case, the hopper capacity will depend upon the difference between unloading rate and outflow rate at the bottom of the hopper.
Regards,
Ishwar G Mulani.
Author of Book : Engineering Science and Application Design for Belt Conveyors.
Author of Book : Belt Feeder Design and Hopper Bin Silo
Advisor / Consultant for Bulk Material Handling System & Issues.
Pune, India.
Tel.: 0091 (0)20 25871916 ■
Longhopper Serenade
Originally Posted by I G Mulani....In this case the entire rake of wagons gets unloaded quickly and leaves the track hopper for next trip. So, in such arrangement, accommodation of the coal content of the entire rake into the hopper is one of the primary consideration for deciding the hopper capacity.
Regards,
Ishwar G Mulani.
Author of Book : Engineering Science and Application Design for Belt Conveyors.
Author of Book : Belt Feeder Design and Hopper Bin Silo
Advisor / Consultant for Bulk Material Handling System & Issues.
Pune, India.
Tel.: 0091 (0)20 25871916
...& good luck when it comes to starting up the 550 tph outbye conveyors. 
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Re: Track Hopper Capacity
Louis right is right if a belt conveyor is used under the hopper in that case.
A twin apron feeder discharging onto a belt conveyor(the apron feeder on the left side feeding left to right and the right apron feeder feeding right to left) disharging into the center
above the conveyor at the incline tail pulley) used for take away works very well.
If a WR Stamler Car mover was used it could move four rakes and the locomotives at one time over a trestle used to dump the coal.
If the twin loop is used a WR Stamler car mover (not meaning to name drop) can be used to do this without cable (meaning wire rope) leaving the locomotives attached etc. as the push pull is directly over the track hopper trestle linearly etc. and the car mover can be placed in the road bed before the dumping point to push and pull back the rakes of cars with the locomotives attached relieving the locomotive driver of any responsibilty and possible derailments
Instead of dumping five cars at once why not simply continually dump them untl the rake iis empty using a hopper wider than the trestle with a hopper length apron feeder linearly positioned to feed directly to the takeaway belt and stock pile.
If you use a pair of 36 inch apron feeders feeding to the center of the hopper and discharging to the belt below it is easily done many of the pulverized coal plants built here use this design
with a pedestal mounted conveyor carrying coal to the edge of the coal pile and moved away with a tracked earth mover
It the merry go round is still in the planning stages it will be a matter of deciding where to put the dumping station and conveyor in a linear path A to B to C being the stock pile if there is room. ■
Track Hopper Capacity
Dear All,
I am working on 350MW TPP. I wanted to know that what are the considerations for designing Track Hopper Capacity for BOBR Wagons. What is the thumb rule for the same?
Regards,
Amit Soni ■