US 4,177,575 A · Organic material treatment process

Abstract

A method and apparatus are disclosed for drying and pelletizing organic material such as animal waste, sewage and the like. The organic material is dried in two stages using a high temperature, rotating primary drying drum, and a lower temperature secondary louvred drying drum. The primary drum includes an inlet section and an outlet section. The inlet section includes a plurality of transverse chain curtains for increased heat transfer to the organic material, for breaking up the organic material and for cleaning the sides of the drum. The primary drum outlet section includes a plurality of vanes angularly attached to the inside of the drum to form an auger to retain the material in the drum until it is partially dried to a desired level. The organic material is then transported to the secondary louvred dryer. The louvred dryer includes an input section, an output section and a central pelletizing section formed by adjacent portions of the input and output sections. The louvred dryer input section is connected to a supply of heated air and the louvred dryer output section is connected to a supply of cooling air. An adjustable baffle is located in the pelletizing section for use when it is desired to pelletize the organic material. The baffle defines a continuous cylindrical rolling surface which blocks the air flow through the louvres in the pelletizing section and which rolls the organic material to form pellets. The longitudinal location and the longitudinal length of the baffle may be adjusted for controlling the point where pelletizing begins and for controlling the size of the pellets. Suitable air-pollution apparatus is provided to prevent atmospheric pollution.

Claims16

Dependent claims

A method of drying and pelletizing organic material such as sewage, the method comprising:

introducing the organic material into a rotating louvred drying drum having longitudinal, circumferentially spaced-apart, radially inwardly disposted louvres, said drum having an input section, an output section and a central pelletizing section formed by adjacent portions of the input and output sections;
passing heated air through the louvred drying drum input section louvres to dry the material, said air being at a temperature between 500.degree. and 800.degree. F. and at a velocity through the drum between 200 and 400 feet per minute;
passing cooling air through the louvred drying drum output section louvres to cool the material;
and interrupting the flow of heated air and cooling air through the louvres in the pelletizing section by closing the louvres to form a cylindrical rolling surface in the pelletizing section, whereby the organic material is rolled in the pelletizing section to form pellets.

1 more element

A method of drying organic material such as animal waste or sewage, the method comprising:

introducing the material into an elongate rotating primary drying drum having an inlet section and an outlet section;
passing a stream of air through the primary drum, said airstream being heated to a temperature between 800.degree. and 2,000.degree. F., and said airstream having a velocity between 350 and 600 feet per minute;
contacting the organic material in the inlet section with a plurality of chains suspended from the walls of the primary drum;
lifting the organic material into the airstream in the outlet section by a plurality of auger vanes attached to the walls of the primary drum, said vanes being angularly disposed so that the material tends to move contra the direction of the stream of air;
controlling the rate of introduction of organic material into the primary drum to maintain the moisture content of the organic material emerging from the primary drum at a predetermined initial level;
introducing the organic material emerging from the primary drum into a rotating secondary louvred drying drum, the secondary drum havng an input section and an output section;
and passing heated air through the secondary drum louvres in the input section, and passing cooling air through the secondary drum louvres in the output section, whereby the organic material is dried in the secondary drum to a desired predetermined final level.

4 more elements

Dependencies are inferred from the claim text.

Organic material treatment process

Life of this patent

Organic material treatment process

Life of this patent

Abstract

Claims16