Provided is an indirectly heated rotary dryer which has achieved enhanced energy-saving performance by reducing heating tubes non-contacting with material to be dried and reducing power required for rotation even when a hold up ratio is increased. Specifically provided is an indirectly heated rotary dryer having four partition walls extended respectively along a shaft center in an inner space of a rotating shell at angle intervals of 90 degrees in the vertical and horizontal directions. The four partition walls partition the inner space of the rotating shell at a lateral section of the rotating shell into four approximately-sector-shaped small spaces respectively extended along the shaft center. Heating tubes are aligned in the rotating shell in three lines extended respectively in parallel to the shaft center of the rotating shell. The heat tubes heat and dry the material to be dried by supplying heated steam to the heating tubes and performing heat exchange with the material to be dried in the rotating shell.

A combination of components for use in making asphalt concrete from a mixture of virgin aggregate material with recycled asphalt products and/or recycled asphalt shingles encompasses a direct dryer for heating virgin aggregate material; a pre-dryer for heating recycled asphalt product and/or recycled asphalt shingles, said pre-dryer using warm exhaust gas from said direct dryer to heat the recycled asphalt product and/or recycled asphalt shingles; and means for conveying warm exhaust gas from said direct dryer to said pre-dryer.

To provide a drying method for processing material and a horizontal rotary dryer allowing easy performance of mass processing of the processing material and enabling size reduction by improving drying performance of the dryer. In a drying method for processing material in which a horizontal rotary dryer provided with: a rotating shell having a feed port for processing material on one end side thereof and a discharge port for processing material on the other end side thereof, and capable of freely rotating around an axial center; and a group of heating tubes through which a heating medium passes, provided within the rotating shell, and configured in a manner that the processing material is lifted up in a rotational direction by the group of heating tubes in accordance with the rotation of the rotating shell, is used, and the processing material is dried, through indirect heating, by using the group of heating tubes in a process of feeding the processing material to the one end side of the rotating shell and discharging the processing material from the other end side of the rotating shell, the rotating shell is rotated to make a critical speed ratio defined by the following expression 1 and expression 2 become 30 to less than 100% to dry the processing material,

Vc=2.21D1/2Expression 1

=V/Vc.Math.100Expression 2

wherein Vc indicates a critical speed (m/s), D indicates an inside diameter (m) of the rotating shell, indicates the critical speed ratio (%), and V indicates a rotation speed (m/s).

To provide a drying method for processing material and a horizontal rotary dryer allowing easy performance of mass processing of the processing material and enabling size reduction by improving drying performance of the dryer. In a drying method for processing material in which a horizontal rotary dryer provided with: a rotating shell having a feed port for processing material on one end side thereof and a discharge port for processing material on the other end side thereof, and capable of freely rotating around an axial center; and a group of heating tubes through which a heating medium passes, provided within the rotating shell, and configured in a manner that the processing material is lifted up in a rotational direction by the group of heating tubes in accordance with the rotation of the rotating shell, is used, and the processing material is dried, through indirect heating, by using the group of heating tubes in a process of feeding the processing material to the one end side of the rotating shell and discharging the processing material from the other end side of the rotating shell, the rotating shell is rotated to make a critical speed ratio defined by the following expression 1 and expression 2 become 30 to less than 100% to dry the processing material,

Vc=2.21D1/2Expression 1

=V/Vc.Math.100Expression 2

wherein Vc indicates a critical speed (m/s), D indicates an inside diameter (m) of the rotating shell, indicates the critical speed ratio (%), and V indicates a rotation speed (m/s).

A device and method for drying fine particulate. A parallel flow rotary drum dryer is used to dry the particulate material. There is a combustion chamber for the burner, located upstream of the dryer inlet, and the burner flame is limited to the combustion chamber so the fine particulate material does not come into direct contact with the burner flame. The output from the dryer passes through a knock-out box including a baffle system with a plurality of narrow gaps to create a pressure drop to slow down the gas flow and enable the entrained fine mesh dry particulate to drop out through a bottom outlet before the effluent gas is sent to the dust collection/air filtration system.

A device and method for drying fine particulate. A parallel flow rotary drum dryer is used to dry the particulate material. There is a combustion chamber for the burner, located upstream of the dryer inlet, and the burner flame is limited to the combustion chamber so the fine particulate material does not come into direct contact with the burner flame. The output from the dryer passes through a knock-out box including a baffle system with a plurality of narrow gaps to create a pressure drop to slow down the gas flow and enable the entrained fine mesh dry particulate to drop out through a bottom outlet before the effluent gas is sent to the dust collection/air filtration system.