Heatec Tec-Notes

Technical Paper T-140
Heating and Storing Asphalt at HMA Plants

Publication No. T-140
download T-140 in PDF format

Pages: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12,
13, 14, 15, 16, 17, 18, 19, 20,
21

 

Horizontal Vs vertical tanks
Heated asphalt storage tanks are cylindrical and may be either horizontal or vertical. Horizontal tanks are installed so their long axes are horizontal and they occupy a ground area equal to their diameter times their length. They are easily equipped with wheels and suspension for highway travel.

Vertical tanks are installed so that their long axes are upwards and they occupy a ground area only the size of their diameter (Figure 61). Consequently, you can fit four vertical tanks in the space of one horizontal tank (Figure 62).

Figure 61. Vertical Tanks Have Small Footprints.
Vertical Asphalt Tanks

 

Figure 62. Ground Area Of Vertical Tanks Vs. Horizontal Tanks.
Footprint of vertical asphalt tanks

Another advantage is that the surface area of asphalt cement exposed to atmosphere inside a vertical tank is smaller than that inside a horizontal tank for the same amount of liquid. Thus, there is less oxidation of asphalt cement in a vertical tank. Moreover, when mixers are installed to keep polymers in suspension, the liquid in vertical tanks has better flow patterns than in horizontal tanks.

However, there are other considerations when polymers are used and the tanks must also be portable. Horizontal tanks are best-suited for portability. But, as already noted, direct-fired tanks are not recommended for polymer-modified asphalts, even though they can be portable. So, the best-suited tanks for both portability and polymer asphalts are horizontal tanks that have coils heated by hot oil. And where only a single tank is needed, a unit that combines a coil tank with a heater, such as a Heli-Tank, is an excellent choice.

Heli-Tanks and other horizontal tanks heated with hot oil can incorporate either a spray bar re-circulation system (Figure 63) or mixers (Figure 64) to keep the polymer from separating from the asphalt. Although the mixing action in a horizontal tank is not as good as in a vertical tank, current experience indicates that the mixing is quite satisfactory. (Please refer to Heatec Technical Paper T-133.)

Figure 63. Horizontal Tank With Re-circulation System For PMAC.
Asphalt tank with spray bar

 

Figure 64. Horizontal Tank With Mixers For PMAC.
mixers in horizontal asphalt tank

← previous page



Home | Profile | Products - Asphalt | Products - Industrial | Products - Concrete
Literature | Tec-Notes | Parts | Service | Employment | Contacts

Please contact Heatec, Inc. at
Phone (423) 821-5200 | Toll-Free (800) 235-5200 | Fax: (423) 821-7673
5200 Wilson Road | P.O. Box 2008 | Chattanooga, Tennessee 37410

©2008 Astec Industries, Inc. All Rights Reserved.
Legal Notice | Privacy Policy | Webmaster


Heat conservation

Considerations

Basic needs

Increasing temperature Vs maintaining it

Heating systems

Direct-fired tanks

Hot oil heaters

Expansion tanks

Electric heaters

Heating fuels

Heavy fuel preheaters

Fuel heating values

Monitoring fuel usage

Heater thermal efficiency

Impact of efficiency

Efficiency factors

Heatec heaters

Determining efficiency

Case histories

Burners

Heat loss

Proper insulation

HMA plant heating costs

Heat requirements

Portability

Equipment layout

Piping

Filters and valves

Asphalt pumps

Hot oil pumps

Asphalt metering

Calibration

Heater controls

Emissions

Containment

Horizontal Vs vertical tanks