CASCADING ENERGY SYSTEM
An energy system for a processing or manufacturing facility is considered a cascading system, as it sequentially utilizes the output product or waste of higher energy processes as at least part of the input energy for lower energy processes. Multiple absorption chillers are incorporated throughout the system along the cascading process stages to step-down the energy in the output product of one stage to at or near the appropriate input energy level for a subsequent stage. Cooling capacity is created by the absorption chillers during each step-down phase for use elsewhere in the facility.
The present invention relates to energy systems for processing and manufacturing facilities.
Resource efficiency and conservation are important aspects of designing processing and manufacturing facilities.
SUMMARYThe present invention provides an improved energy system for a processing or manufacturing facility. The system is considered a cascading system, as it sequentially utilizes the output product or waste of higher energy processes as at least part of the input energy for lower energy processes. Multiple absorption chillers are incorporated throughout the system along the cascading process stages to “step-down” the energy in the output product of one stage to at or near the appropriate input energy level for a subsequent stage. Cooling capacity is created by the absorption chillers during each step-down phase for use elsewhere in the facility.
Additionally, the system is a fully balanced system in terms of water consumption. Fluid flow rates are determined for the entire system such that little or no excess water is used and/or wasted. The system is designed such that components in the system get precisely the amount of water needed for each specific operation. Therefore, water consumption, and the associated costs, are also reduced as compared to existing systems.
In one embodiment, the invention provides an energy system for a facility. The energy system includes a first process stage resulting in an output fluid at a first temperature T1, a second process stage utilizing an input fluid at a second temperature T2 lower than the first temperature T1, and a third process stage utilizing an input fluid at a third temperature T3 lower than both the first and second temperatures T1 and T2. The system further includes a first absorption chiller in fluid communication between the first process stage and the second process stage. The first absorption chiller is operable to reduce the temperature of the output fluid of the first process stage from the first temperature T1 to the second temperature T2 to provide the input fluid for the second process stage. The system also includes a second absorption chiller in fluid communication between the first absorption chiller and the third process stage. The second absorption chiller receives fluid at the second temperature T2 from the first absorption chiller and is operable to further reduce the temperature of the fluid to the third temperature T3 to provide the input fluid for the third process stage.
No additional fluid is added to the output fluid in the system between the first process stage and the second process stage, or between the first process stage and the third process stage. Furthermore, no additional fluid is added to the output fluid in the second process stage. Additional fluid is added to the output fluid in the third process stage.
Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.
Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways.
Referring to
As a result of the rendering operation at the rendering station 38, condensate returns to the boiler system 22 at line 50. Additionally, the rendering operation results in output fluid or waste fluid in the form of water at a temperature T1 of about 200 degrees Fahrenheit at line 54. The output fluid maintains the flow rate of between about 700 to about 1,050 gallons per minute, and in the illustrated embodiment, a flow rate of about 712 gallons per minute for a lower capacity system and about 1,045 gallons per minute for a higher capacity system. In other embodiments, the output fluid could be steam or other gas/liquid combinations. As a byproduct of the high energy rendering operation, the output fluid is at a lower energy (i.e., a lower temperature) than the input fluid (i.e., steam) to the rendering operation. However, the cascading energy system 10 will make use of the output fluid from the rendering stage as at least a portion of the input fluid for one or more subsequent, lower energy operations. The output fluid can be collected in one or more surge tanks 58 to accommodate pressure changes in the system and until needed for the next section of the energy system 10. In the illustrated embodiment, three to six 75,000 gallon surge tanks can be used depending on system requirements and capacity. Line 62 provides fluid communication for the output fluid between the surge tanks 58 and the next sections 66a and 66b (see
The fluid flow rate of the output fluid from the surge tanks 58 can be regulated to between about 500 to about 750 gallons per minute depending on system requirements and capacity. For a lower capacity system, the flow rate can be about 504 gallons per minute, while for a higher capacity system, the flow rate can be about 740 gallons per minute. Conventional rendering operations typically result in much higher output flow rates (e.g., about 1,500 gallons per minute for lower capacity systems and about 2,200 gallons per minute for higher capacity systems) of waste water at about 140 degrees Fahrenheit, much of which is simply dumped to a wastewater treatment stage or a sewer without being used further. In these conventional systems, the 1,500 to 2,200 gallons per minute flow rate is what is provided from the well or water source, and is at least about double that necessary with the present invention. The additional water results in a smaller temperature increase in the output water, which is why the conventional waste water exiting the rendering stage is only at about 140 degrees Fahrenheit. Therefore, with the energy system 10 of the present invention, more of the waste heat is retained for subsequent use. As will be further understood from the description below, the energy system 10 is a balanced system in terms of water consumption, such that little or none of this initial output fluid is wasted.
The illustrated chiller 70 is a conventional lithium-bromide type absorption chiller. Water enters the chiller 70 at about 60 degrees Fahrenheit in line 90 and exits the chiller 70 at about 50 degrees Fahrenheit in line 94. The 50 degree water is used in the facility's ammonia refrigeration system 66b, as shown in
The 200 degree Fahrenheit water in line 62 enters the one or more absorption chillers 70 at a flow rate of between about 450 to about 700 gallons per minute depending on system requirements and capacity. For example, a lower capacity system might use a 285 ton absorption chiller receiving water at about 472 gallons per minute and a higher capacity system might use a 457 ton chiller receiving water at about 692 gallons per minute. These flow rates result from the output fluid from the surge tanks 58 being blended with other 200 degree Fahrenheit water provided from microturbines 228 and 240 (and possibly from turbine 252) at a lower relative flow rate (e.g., 425 to 650 gallons per minute), as discussed below with respect to an electricity generation stage 224 (see
Referring again to
The portion of the 177 degree Fahrenheit water exiting the first chiller 70 and that does not get diverted to the second chiller 112 continues in line 86 to a second process stage 120, which in the illustrated embodiment, is an equipment (e.g., knife) sterilization stage or operation illustrated in
Referring again to
The illustrated booster water heater 136 is provided with a natural gas supply 140 to heat the 177 degree Fahrenheit water to about 180 degrees Fahrenheit. Because the input water at 177 degrees Fahrenheit is so close to the 180 degree Fahrenheit temperature requirement for the sterilization stage 120, the lower energy consumption booster water heater 136 can be used instead of a larger, higher energy consuming boiler. In conventional systems, well water or water at about 140 degrees Fahrenheit must be heated to 180 degrees Fahrenheit for the sterilization stage, thereby requiring a boiler and the use of more energy. In the event that the water in line 86 is coming from the facility's heating system due to winter bypass, the booster water heater 136 may not be required, as the water in line 86 may be at about 180 degrees Fahrenheit.
The 180 degree Fahrenheit water is provided by line 144 to one or more knife or other equipment sterilizers 148 for an equipment sterilization operation. The water used for the equipment sterilization process is then sent in line 152 to another process stage of the energy system 10, and in the illustrated embodiment, to a wastewater treatment stage to be discussed further below. Alternatively, the water used in the equipment sterilization process can be sent through line 152 to a sewer.
Referring to
The input fluid to the sanitation stage 160 passes through one or more surge tanks 164, and enters line 168 where it is mixed with cold well water from line 172 at about 55 degrees Fahrenheit and flowing at a rate of about 100 to about 200 gallons per minute to cool the 167 degree Fahrenheit input fluid to about 140 degrees Fahrenheit. In the illustrated embodiment, two to four 75,000 gallon surge tanks 164 can be used depending on system requirements and capacity. The surge tanks 164 in combination with the supply of well water from line 172 cooperate to regulate the pressure of the input fluid to a value suitable for the sanitation process or processes 176. In the illustrated embodiment, pressure requirements for fluid used in the sanitation process 176 can range from about 80 to about 300 pounds per square inch. The water balance of the system 10 is maintained as only the required amount/flow of well water is added to achieve the output needed for the sanitation process 176.
The 140 degree Fahrenheit water is then used in a sanitation process or processes 176 to sanitize various equipment and features within the facility. Output fluid from the sanitation process 176 travels through line 180 to another process stage of the energy system 10, and in the illustrated embodiment, to the wastewater treatment stage to be discussed further below. Alternatively, the water used in the sanitation process can be sent through line 180 to a sewer.
The illustrated electricity generation stage 224 further includes a second microturbine or microturbines 240 powered by a natural gas supply 244 to generate electricity that is output to line 232 for the facility's electrical system. Suitable microturbines 240 are available from Capstone under model numbers C65 and C65-ICHP (65 kW). As with the microturbines 228, the microturbines 240 can be cooled by water provided/diverted from lines 116, 116′ at the temperature T3 of about 167 degrees Fahrenheit. The flow rate of cooling water to the microturbines 240 ranges from about 250 to about 500 gallons per minute, with the lower capacity system having a flow rate of about 273 gallons per minute (440 gpm−167 gpm=273 gpm) and the higher capacity system having a flow rate of about 477 gallons per minute (644 gpm−167 gpm=477 gpm). The flow rate of the heated water exiting the microturbine 240 remains the same as the flow rate of the cooling water entering the microturbine 240. The cooling fluid is heated via heat exchange with the microturbines 240 to about 200 degrees Fahrenheit and exits the microturbines 240 at line 236, combining with the heated cooling fluid exiting the microturbine 128, where it then returns to the absorption section 66a by fluid communication with lines 62, 62′, thereby providing an additional or alternate source of high-energy output or waste fluid for the energy cascading system 10. As shown in
Referring now to
Referring again to
Those skilled in the art will understand that modifications to the illustrated embodiment can be made without departing from the scope of the invention. For example, it is understood that while each of the rendering stage 14, the electricity generation stage 224, and the electricity generation stage 248 can together provide the source of high-energy water at the first temperature T1, other embodiments may include fewer or more stages to provide the source of high-energy water used in the cascading energy system 10. Furthermore, the number of stages utilizing input fluid at each of the second temperature T2 and the third temperature T3 can vary from the illustrated embodiment. Furthermore, and as mentioned above, the specific processes described with respect to each stage and the specific water temperatures and flow rates set forth in the above description of the illustrated embodiment are by way of example only, and can vary depending upon the specific facility in which the energy system 10 is utilized.
In addition, the system can be utilized in facilities in which the initial output or waste fluid is steam instead of hot water. Steam absorption chillers can be used in place of or in combination with the illustrated water absorption chillers 70, 70′, 112, 112′ to vary the number of energy step-down phases as appropriate for the particular system.
Various features and advantages of the invention are set forth in the following claims.
Claims
1. An energy system for a facility, the energy system comprising:
- a first process stage resulting in an output fluid at a first temperature T1;
- a second process stage utilizing an input fluid at a second temperature T2 lower than the first temperature T1;
- a third process stage utilizing an input fluid at a third temperature T3 lower than both the first and second temperatures T1 and T2;
- a first absorption chiller in fluid communication between the first process stage and the second process stage, the first absorption chiller operable to reduce the temperature of the output fluid of the first process stage from the first temperature T1 to the second temperature T2 to provide the input fluid for the second process stage; and
- a second absorption chiller in fluid communication between the first absorption chiller and the third process stage, the second absorption chiller receiving fluid at the second temperature T2 from the first absorption chiller and operable to further reduce the temperature of the fluid to the third temperature T3 to provide the input fluid for the third process stage.
2. The energy system of claim 1, wherein the first process stage is an animal rendering stage, the second process stage is an equipment sterilization stage, and the third process stage is a sanitation stage.
3. The energy system of claim 2, wherein the first temperature T1 of the output fluid from the rending stage is about 200 degrees Fahrenheit, wherein the second temperature T2 of the input fluid to the equipment sterilization stage is about 177 degrees Fahrenheit, and wherein the third temperature T3 of the input fluid to the sanitation stage is about 167 degrees Fahrenheit.
4. The energy system of claim 2, wherein the energy system further includes a heater in the equipment sterilization stage to heat the input fluid to a sterilization temperature above the second temperature T2.
5. The energy system of claim 2, wherein the energy system further includes a cold water supply in the sanitation stage to mix cold water with the input fluid to cool the input fluid to a sanitation temperature below the third temperature T3.
6. The energy system of claim 1, further comprising a fourth process stage, wherein an output fluid from at least one of the second and third process stages is an input fluid for the fourth process stage, and a fifth process stage, wherein an output from the fourth process stage provides an energy source to the fifth process stage.
7. The energy system of claim 6, wherein the fourth process stage is a wastewater treatment stage and wherein the fifth process stage is an electricity generation stage, the wastewater treatment stage providing methane gas to power a turbine used for the electricity generation stage.
8. The energy system of claim 1, further comprising an electricity generation stage and wherein at least a portion of the fluid reduced to the third temperature T3 by the second absorption chiller is diverted to the electricity generation stage to act as a cooling fluid for a turbine used in the electricity generation stage.
9. The energy system of claim 8, wherein the electricity generation stage results in an output fluid at about the first temperature T1 and that is provided to the first absorption chiller.
10. The energy system of claim 8, wherein natural gas is used to power the turbine.
11. The energy system of claim 1, wherein the first and second absorption chillers provide cooling capacity for the energy system.
12. The energy system of claim 11, wherein the first and second absorption chillers provide a chilled output fluid at a temperature of about 50 degrees Fahrenheit.
13. The energy system of claim 1, wherein the first process stage is an electricity generation stage, the second process stage is an equipment sterilization stage, and the third process stage is a sanitation stage.
14. The energy system of claim 13, wherein a portion of the fluid reduced to the third temperature T3 by the second absorption chiller is diverted to the electricity generation stage to act as a cooling fluid for a turbine used for the electricity generation stage.
15. The energy system of claim 13, further comprising a wastewater treatment stage, wherein output fluid from at least one of the equipment sterilization stage and the sanitation stage is an input fluid for the wastewater treatment stage, and wherein methane gas generated at the wastewater treatment stage powers a turbine used for the electricity generation stage.
16. The energy system of claim 13, wherein the first temperature T1 of the output fluid from the electricity generation stage is about 200 degrees Fahrenheit, wherein the second temperature T2 of the input fluid to the equipment sterilization stage is about 177 degrees Fahrenheit, and wherein the third temperature T3 of the input fluid to the sanitation stage is about 167 degrees Fahrenheit.
17. The energy system of claim 13, further comprising an animal rendering stage that results in an output fluid at about the first temperature T1 and that is provided to the first absorption chiller.
18. The energy system of claim 1, further comprising a first cooling tower in fluid communication with the first absorption chiller and a second cooling tower in fluid communication with the second absorption chiller.
19. The energy system of claim 1, wherein the first absorption chiller includes at least two absorption chillers in fluid communication, and wherein the second absorption chiller includes at least two absorption chillers in fluid communication.
20. The energy system of claim 1, further including a bypass line between the first process stage and the second process stage such that output fluid from the first process stage selectively bypasses the first and second absorption chillers.
21. The energy system of claim 1, wherein the output fluid is regulated to a flow rate that provides a balanced system of water consumption so that little or none of the output fluid is wasted.
22. The energy system of claim 21, wherein no additional fluid is added to the output fluid in the system between the first process stage and the second process stage, or between the first process stage and the third process stage.
23. The energy system of claim 22, wherein no additional fluid is added to the output fluid in the second process stage.
24. The energy system of claim 22, wherein additional fluid is added to the output fluid in the third process stage.
25. The energy system of claim 21, wherein at least one surge tank is provided to regulate the flow rate of the output fluid.
26. The energy system of claim 21, wherein the output fluid is regulated to a flow rate of about 500 to about 750 gallons per minute.
Type: Application
Filed: Apr 14, 2010
Publication Date: Oct 20, 2011
Applicant: A. EPSTEIN & SONS INTERNATIONAL, INC. (Chicago, IL)
Inventors: Jeremy R. Poling (Glendale, WI), Darrin D. McCormies (Orland Hills, IL)
Application Number: 12/760,036