Process and apparatus for treating waste

A heat exchanger for transferring heat between first waste solids and second waste solids, said heat exchanger comprising:

• a first waste solids source for supplying first waste solids;
• a second waste solids source separate from said first waste solids source and for supplying second waste solids, the second waste solids being at a temperature different from the first waste solids;
• a heat transfer portion remotely located from and fluidly interconnected with said first waste solids source and said second waste solids source, said heat transfer portion including
• a first channel in fluid communication with said first waste solids source such that first waste solids from said first waste solids source are passed through said first channel, and
• a second channel in fluid communication with said second waste solids source such that second waste solids from said second waste solids source are passed through said second channel, said second channel having a thermally-conducting wall disposed substantially adjacent said first channel for transferring heat between first waste solids and second waste solids passing through said heat transfer portion;
• a recirculating system fluidly interconnected with said first channel such that at least a portion of the first waste solids is passed through said first channel at least twice, wherein said first channel has an inlet and an outlet, and wherein said recirculating system includes a conduit connecting said outlet to said inlet so that the portion of the first waste solids passed through said first channel is recirculated through said first channel;
• a valve fluidly connected to said conduit and operable to selectively direct at least a portion of the first waste solids through said conduit such that the portion of the first waste solids is recirculated through said first channel;
• and
• a tank fluidly connected with and receiving waste solids from said first waste solids source, wherein said valve is operable to selectively direct the portion of the first waste solids through said recirculation system to return to said first waste solids source and to direct an other portion of the first waste solids to said tank.

A heat exchanger for transferring heat between first waste solids and second waste solids, said heat exchanger comprising:

• a first waste solids source for supplying first waste solids;
• a second waste solids source separate from said first waste solids source and for supplying second waste solids, the second waste solids being at a temperature different from the first waste solids;
• a heat transfer portion remotely located from and fluidly interconnected with said first waste solids source and said second waste solids source, said heat transfer portion including
• a first channel in fluid communication with said first waste solids source such that first waste solids from said first waste solids source are passed through said first channel, and
• a second channel in fluid communication with said second waste solids source such that second waste solids from said second waste solids source are passed through said second channel, said second channel having a thermally-conducting wall disposed substantially adjacent said first channel for transferring heat between first waste solids and second waste solids passing through said heat transfer portion;
• a first recirculating system fluidly interconnected with said first channel such that at least a portion of the first waste solids is passed through said first channel at least twice, wherein said first channel has an inlet and an outlet, and wherein said recirculating system includes a first conduit connecting said outlet of said first channel to said inlet of said first channel so that the portion of the first waste solids passed through said first channel is recirculated through said first channel;
• and
• a second recirculating system fluidly interconnected with said second channel such that at least a portion of the second waste solids is passed through said second channel at least twice, wherein said second channel has an inlet and an outlet, and wherein said second recirculating system includes a second conduit connecting said outlet of said second channel to said inlet of said second channel so that the portion of the second waste solids is recirculated through said second channel.

A heat exchanger for transferring heat from first waste solids to second waste solids, said heat exchanger comprising:

• a first waste solids source for supplying first waste solids;
• a second waste solids source separate from said first waste solids source and for supplying second waste solids, the second waste solids being at a temperature different from the first waste solids;
• a heat transfer device remotely located from and fluidly interconnected with said first waste solids source and said second waste solids source, said heat transfer device including
• a first channel in fluid communication with said first waste solids source and for conveying first waste solids from said first waste solids source, and
• a second channel in fluid communication with said second waste solids source and for conveying second waste solids from said second waste solids source, said second channel having a thermally-conducting wall disposed substantially adjacent said first channel for transferring heat between first waste solids and second waste solids passing through said heat transfer device;
• and
• a recirculating system for selectively causing recirculating flow of first waste solids from said first waste solids source through said first channel and back to said first waste solids source.

A heat exchanger for transferring heat from first waste solids to second waste solids, said heat exchanger comprising:

• a first waste solids source for supplying first waste solids;
• a second waste solids source remote from said first waste solids source and for supplying second waste solids, the second waste solids being at a temperature different from the first waste solids;
• a heat transfer device remote from said first waste solids source and said second waste solids source, said heat transfer device including
• a first channel in fluid communication with said first waste solids source for passing first waste solids through said heat transfer device, said first channel having an inlet and an outlet, and
• a second channel in fluid communication with said second waste solids source for passing second waste solids through said heat transfer device such that, when first waste solids and second waste solids move through said heat transfer device, heat is transferred between the first waste solids and the second waste solids;
• and
• a recirculation device fluidly interconnecting said first waste solids source and said first channel such that at least a portion of the first waste solids from said first waste solids source is passed through said first channel and returned to said first waste solids source, said recirculation device including a conduit connecting said outlet to said inlet so that the portion of the first waste solids is recirculated through said first channel and returned to said one of said first waste solids source.