Limestone Railcar
Fran,
The concept of unloading a railcar by pressure is essentially no different than that used to unload a tipping tanker or a stationary blow tank. In this case, the conveying pressure can not exceed 2 bar.
The conveying air supply would be split upstream of the railcar, a portion going to top of the railcar and a portion going directly to the conveying line just upstream of the pickup point. The solids conveying rate is influenced by the slot opening at bottom of the railcar hopper section and the split of air going to the top of the railcar. These parameters can be increased until the desired conveying pressure, say, 1.5 bar, is achieved.
A realistic estimate of conveying rate for the 4" pipeline that you described is 6 to 8 t/h. The total air supply to the system would be in the range of 16 to 17 m3/m.
Dennis Hauch ■
Re: Limestone Railcar
Originally posted by Dennis Hauch
Fran,
The concept of unloading a railcar by pressure is essentially no different than that used to unload a tipping tanker or a stationary blow tank. In this case, the conveying pressure can not exceed 2 bar.
The conveying air supply would be split upstream of the railcar, a portion going to top of the railcar and a portion going directly to the conveying line just upstream of the pickup point. The solids conveying rate is influenced by the slot opening at bottom of the railcar hopper section and the split of air going to the top of the railcar. These parameters can be increased until the desired conveying pressure, say, 1.5 bar, is achieved.
A realistic estimate of conveying rate for the 4" pipeline that you described is 6 to 8 t/h. The total air supply to the system would be in the range of 16 to 17 m3/m.
Dennis Hauch
Dear Mr. Hauch,
I am also curious as to whether the rail cars she is referring to have a central delivery pipe which would facilitate faster unloading and by a single stream of low pressure high volume air pushing the material through the hopper bottom and whether the rail car has separate discharge pipes which would facilitate hopper bottom unloading I am also curious as to whether the cars are made by ISOVEYOR as well. ■
Limestone Railcar
Fran
Dennis Hauch has summed up the situation admirably. You can work with an air supply pressure up to the maximum rating of your rail cars. The higher the air supply pressure the higher the limestone flow rate.
With an air supply pressure of 2 bar gauge I would recommend a slightly higher air flow rate of 22 m3/min for such a granular material and for your pipeline I would expect the material flow rate to be closer to 15 tonne/h, which could be improved by stepping the pipeline to 5 inch bore part way along the length.
If the base of the rail car is porous, as with an 'air slide', most of the air directed to the rail car during discharge should be to the 'air slide'. Flow rate control is achieved by proportioning the 22 m3/min between that directed into the rail car and that injected into the pipeline at outlet from the rail car. ■
Railcars Unloading
Dear Fran
to reach 20 – 30 t/h conveying capacity you need the pipeline diameter DN 125. I presume that the railcar outlet diameter is DN 100. So you need a “reducer” in the pipeline beginning to enlarge the pipeline diameter and to add the air into the pipeline. The air pressure 2 bar is suitable for this solution. I am able to prepare an engineering of unloading equipment for you.
Petr Rayman
Technical Director
RAYMAN spol. s r. o. Kladno
Czech Republic
tel. +420 382 522 115
fax +420 382 522 117
E-mail: petr.rayman@rayman.cz
Web site: www.rayman.cz ■
Re: Limestone Railcar
Hi all again:
Thank´s for your attention and for the information.
Probably I´ll try to use a bigger diameter to improve the conveying rate.
Let´s see if this thing works! ■
Limestone Railcar
Hi all,
I have to unload silo-ralicars carrying dry limestone 0-2mm size ( all the range mixed up).The railcar owner tells me that they are designed for working at 2 bar pressure.
The idea is to pressurize the tank of the railcar (33,5 m3)(with a blower) to unload the material ,and to push it into a 4” pipe, where and inyection of air at 2 bar should be done (may be ?). (I suposse 2 bar if I don’t want the to push back the limestone into the railcar again).
This pipe has four 90º bends and about 85 meters length in horizontal and 23 meters vertical untill it reaches the silo(all 4").
My questions are:
Will this thing work, if it is supossed to convey 20-30 tn/hour?
How much air should I inject?
Something I should care about?
I don´t really think this works, so I am thinking about using boosters…(some told me about just conecting air from a blower…). How many boosters should I install and how?.
Do you know who could supply this boosters or other suitable solution, and give support in Spain?
Will I have segregation ?
Thanks in advance for the help.
Fran ■