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US 11,788,790 B2Granted
Low energy drying of swine lagoon sludge or digestate
AssigneeNorth Carolina State University
InventorsChristopher B. Hopkins, Joseph L. Stuckey
Life of this patent
Estimating the term…
Abstract
Devices, systems, and methods for drying a bulk waste product, such as animal waste, having a moisture content of 95% or more water can include a trough configured to receive the bulk waste product and to dispense it in a form suitable for convective drying, one or more conveyors having an air-permeable conveyor belt, each conveyor receiving the waste product from the trough and transporting the waste product along a transport path; and one or more air moving devices (AMDs) that pass air through the air-permeable conveyor belt and across the waste product as it is transported along the transport path to transform the bulk waste product into a dried waste product having a moisture content of about 5% to about 20%, inclusive.
Claims20
A waste drying system, the system comprising:
- a trough comprising:
- a hopper configured to receive a bulk waste product;
- and
- an extruder configured to extrude the bulk waste product in a form of an extruded waste product that is suitable for convective drying, wherein the trough defines a first end of the system;
- a housing comprising a first opening, which is at a boundary of the housing with an external environment comprising ambient air, and a second opening;
- one or more conveyors having an air-permeable conveyor belt, each conveyor being positioned in the second opening and configured to receive the extruded waste product from the trough for transport along a path from the first end of the system to a second end of the system, wherein the second end of the system is at an opposite end of the conveyors from the first end of the system;
- and
- one or more air moving devices (AMDs) mounted in the first opening and configured to pull the ambient air from the external environment into the housing, at the first opening, and to exhaust the ambient air from the housing through the air-permeable conveyor belt, at the second opening, and across the extruded waste product while being transported on the air-permeable conveyor belt along the path from the first end of the system to the second end of the system;
- wherein the system is configured to transform the extruded waste product into a dried waste product having a moisture content of about 5% to about 20%, inclusive, without use of any heat source for heating the ambient air during transport of the extruded waste product from the first end of the system to the second end of the system, wherein the one or more conveyors comprise a first conveyor and second conveyor and the one or more AMDs comprise a first AMD and a second AMD, the system comprising:
- a first drying stage comprising the first conveyor and the first AMD;
- a second drying stage comprising the second conveyor and the second AMD;
- and
- a controller configured to simultaneously and independently control the first and second drying stages to coordinate a transport speed of the extruded waste product along the air-permeable conveyor belt of the first and second conveyors, respectively, as well as a flow of the ambient air produced by each of the first and second AMDs.
10 more elements
A waste drying system, the system comprising:
- a trough configured to receive a bulk waste product and to dispense the bulk waste product in a form suitable for convective drying, wherein the trough defines a first end of the system;
- a first drying stage comprising:
- a first housing comprising a first opening, which is at a boundary of the first housing with an external environment comprising ambient air, and a second opening;
- a first conveyor having an air-permeable conveyor belt, the first conveyor being positioned in the second opening of the first housing and configured to receive the bulk waste product from the trough for transport along a length of the first conveyor, away from the first end of the system;
- and
- a first air moving device (AMD) mounted in the first opening of the first housing and configured to pull the ambient air from the external environment into the first housing, at the first opening of the first housing, and to exhaust the ambient air from the first housing through the air-permeable conveyor belt of the first conveyor, at the second opening of the first housing, and across the bulk waste product while being transported on the air-permeable conveyor belt along the length of the first conveyor;
- wherein the first drying stage is configured to transform the bulk waste product into a partially dried waste product;
- a second drying stage comprising:
- a second housing comprising a first opening, which is at a boundary of the second housing with the external environment comprising ambient air, and a second opening;
- a second conveyor having an air-permeable conveyor belt, the second conveyor being positioned in the second opening of the second housing and configured to receive the partially dried waste product from the first conveyor and transport the partially dried waste product along a length of the second conveyor, towards a second end of the system, wherein the second end of the system is at an end of the second conveyor that is furthest from the first end of the system;
- and
- a second air moving device (AMD) mounted in the first opening of the second housing and configured to pull the ambient air from the external environment into the second housing, at the first opening of the second housing, and to exhaust the ambient air from the second housing through the air-permeable conveyor belt of the second conveyor, at the second opening of the second housing, and across the partially dried waste product while being transported on the air-permeable conveyor belt along the length of the second conveyor;
- wherein the second drying stage is configured to transform the partially dried waste product into a dried waste product;
- and
- a controller configured to simultaneously and independently control the first and second drying stages to coordinate a transport speed of the bulk waste product along the air-permeable conveyor belt of the first conveyor and of the partially dried waste product along the air-permeable conveyor belt of the second conveyor, respectively, as well as a flow of the ambient air produced by each of the first and second AMDs,
- wherein the system is configured to transform the bulk waste product into the dried waste product, which has a moisture content of about 5% to about 20%, inclusive, without use of any heat source for heating the ambient air during transport of the waste product through the first and second drying stages.
13 more elements
Dependencies are inferred from the claim text.