Control system for particulate material drying apparatus and process

• US 7,987,613 B2
• Filed: 08/08/2005
• Issued: 08/02/2011
• Est. Priority Date: 10/12/2004
• Status: Active Grant

• Current Assignee: Rainbow Energy Center LLC
• Original Assignee: Great River Energy
• Inventors: Coughlin, Matthew P, Johnson, Adam M, Ness, Mark A, Wheeldon, John M
• Primary Examiner(s): GRAVINI, STEPHEN MICHAEL
• Application Number:
  US11/199,744
• Publication Number:
  US 20060112588A1
• Time in Patent Office: 2,185 Days
• Field of Search: 343/60, 341/38, 341/80, 34/80, 34/90, 110/249, 202/99, 444/92
• US Class Current: 34/138
• CPC Class Codes: C10L 9/08 by heat treatments, e.g. calcining
• CPC Class Codes: Y02E 20/12 Heat utilisation in combustion or incineration of waste

Abstract

A control system for controlling the utilization of heated waste streams for fluidizing particulate matter such as coal in a fluidizing bed dryer. The control system includes a number of graphic user interfaces that allow an operator to more easily monitor and/or control the various regulator devices. The control system controls coal handling or transportation, fluid handling or flow, and the discharge of discarded or separated coal from the dryer.

Claims

1. A system for controlling the operation of a low-temperature, open-air process for reducing moisture contained within particulate material, wherein such process incorporates a source of wet particulate material, a dryer apparatus, a first heat exchanger operatively connected to the dryer apparatus, and a first waste heat source provided to the first heat exchanger for delivering heat content contained within the first waste heat source to the dryer apparatus, a second heat exchanger operatively connected to the dryer apparatus, a second waste heat source different in type from the first waste heat source provided to the second heat exchanger for delivering heat content contained within the second waste heat source to the dryer apparatus, such controller system comprising:

(a) means for regulating delivery of the wet particulate material to the dryer apparatus;

(b) means for regulating the delivery of the first waste heat source to the first heat exchanger;

(c) means for regulating the delivery of the second waste heat source different in type from the first waste heat source to the second heat exchanger;

(d) means for actively combining predetermined amounts of heat content contained within the first waste heat source and second waste heat source to deliver an aggregate heat content to or within the dryer apparatus;

(e) means for maintaining the particulate material within the dryer apparatus exposed to the aggregate heat content for a sufficient temperature and time duration to achieve the desired degree of moisture reduction to produce dried particulate material; and

(f) means for regulating delivery of the dried particulate material discharged from the dryer apparatus to a dried particulate material discharge destination;

(g) wherein “

waste heat source”

means a gaseous or liquid stream having an elevated heat content resulting from operation of a process or piece of equipment used within an industrial plant operation different from the dryer apparatus, such gaseous or liquid stream being used for the secondary purpose of providing heat content to the particulate material moisture reduction process.

2. The controller system of claim 1, wherein the dryer apparatus is a fluidized-bed dryer.

3. The controller system of claim 1, wherein the dryer apparatus is a fixed-bed dryer.

4. The controller system of claim 1, wherein the particulate material is coal.

5. The controller system of claim 1, wherein the waste heat sources are selected from the group consisting of cooling water streams, hot condenser cooling water, hot flue or stack gas, waste process steam, and discarded heat from operating equipment.

6. The controller system of claim 1, wherein the predetermined temperature delivered to the dryer apparatus by the heat source does not exceed 300°

F.

7. The controller system of claim 1, wherein the predetermined temperature delivered to the dryer apparatus by the combined first and second waste heat sources is about 200-300°

F.

8. The controller system of claim 1 further comprising means for regulating the delivery of at least one additional waste heat source to the dryer apparatus by means of an associated heat exchanger to which was provided an additional type of waste heat, wherein “

waste heat source”

means a gaseous or liquid stream having an elevated heat content resulting from an operation of a process or piece of equipment used within an industrial plant operation different from the dryer apparatus, such gaseous or liquid stream being used for the secondary purpose of providing heat content to the particulate material moisture reduction process.

9. The controller system of claim 1 further comprising means for regulating the delivery of at least one additional heat source to the dryer apparatus by means of an associated heat exchanger to which was provided a principal heat source, wherein “

principal heat source”

means a quantity of heat produced for the principal purpose of providing heat content to the dryer apparatus.

10. The controller system of claim 1, wherein the low-temperature, open-air, moisture-reduction process is used as part of a manufacturing operation.

11. The controller system of claim 10, wherein the manufacturing operation is an electric power plant.

12. The controller system of claim 1, wherein such low-temperature, open-air, moisture-reduction process further comprises:

(a) a fluidizing bed contained within the dryer apparatus for receiving a fluidizing stream to achieve repartition of fluidized particles and non-fluidized particles within the particulate material contained within the fluidized bed;

(b) a source of fluidizing stream operatively connected to the dryer apparatus;

(c) a conveyor means for transporting the non-fluidized particles inside the fluidized bed to the exterior of the dryer apparatus separate from the dried particulate material discharged therefore;

(d) means for regulating the operative connection of the fluidizing stream to the dryer apparatus; and

(e) means for regulating the operation of the conveyor means.

13. The controller system of claim 12, wherein the conveyor means is a screw auger.

14. The controller system of claim 12, wherein the fluidizing stream is air.

15. The controller system of claim 12, wherein the fluidizing stream is an inert gas.

16. The controller system of claim 12, wherein the fluidizing stream is heated by one of the waste heat sources prior to operative communication to the dryer apparatus.

17. The controller system of claim 12, wherein the non-fluidized particles removed by the conveying means from the dryer apparatus enhance the flow of the particulate material through the dryer apparatus to the dried particulate material delivery means.

18. The controller system of claim 12, wherein the non-fluidized particles removed from the fluidized dryer separately from the dried particulate material discharge stream contains an increased weight percentage of at least one contaminant contained within the wet particulate material feed relative to the weight percentage of that contaminant within the wet particulate material feed.

21. The controller system of claim 1, wherein the particulate material is lignite coal whose moisture level in the dried particulate material is reduced to a value of 10-35% wt.

22. The controller system of claim 21, wherein the moisture level in the dried particulate material is reduced to 27-32% wt.

23. The controller system of claim 1, wherein the particulate material is subbituminous coal whose moisture level in the dried particulate material is reduced to a value of 10-30% wt.

24. The controller system of acclaim 23, wherein the moisture level in the dried particulate material is reduced to 20-25% wt.

25. The controller system of claim 1 further comprising means for regulating the delivery of a third waste heat source to a third heat exchanger operatively connected to the dryer apparatus, wherein “

waste heat source”

means a gaseous or liquid stream having an elevated heat content resulting from an operation of a process or piece of equipment used within an industrial plant operation different from the dryer apparatus, such gaseous or liquid stream being used for the secondary purpose of providing heat content to the particulate material moisture reduction process.

26. The controller system of claim 25, wherein the predetermined temperature delivered to the dryer apparatus by the combined heat sources does not exceed 300°

F.

27. The controller system of claim 26, wherein the predetermined temperature delivered to the dryer apparatus by the combined heat sources is 200-300°

F.

28. The controller system of claim 1 further comprising means for regulating the operation of a discharge gate on a storage bunker containing the source of wet particulate material for controlling the discharge of particulate material from the wet particulate material storage bunker.

29. The controller system of claim 1 further comprising means for regulating the operation of a feed conveyor for transporting the wet particulate material to the dryer apparatus.

30. The controller system of claim 1 further comprising means for regulating the operation of a discharge gate on the dryer apparatus for controlling the discharge of the dried particulate material from the dryer apparatus.

31. The controller system of claim 1 further comprising means for regulating the operation of a discharge conveyor for transporting the dried particulate material discharged from the dryer apparatus to the a dried particulate material discharge destination.

41. The controller system of claim 1, wherein the active combining of the first waste heat source and the second waste heat source occurs inside a mixing box positioned outside the dryer apparatus.

42. The controller system of claim 1, wherein the active combining of the first waste heat source and the second waste heat source occurs within two heat exchangers positioned in series outside the dryer apparatus.

43. The controller system of claim 1, wherein the active combining of the first waste heat source and the second waste heat source occurs within a common heat exchanger positioned inside the dryer apparatus.

19. A system for controlling the operation of a low-temperature, open-air process for reducing moisture contained within particulate material, wherein such process incorporates a wet particulate material storage bunker, a feed conveyor, a dryer apparatus, a heat exchanger operatively connected to the dryer apparatus, a heat source provided to the heat exchanger for delivering heat content contained within the heat source to the dryer apparatus, a discharge conveyor, and a dried particulate material discharge destination, such controller system comprising:

(a) means for regulating the operation of a discharge gate on the wet particulate material storage bunker for controlling the discharge of particulate material from the wet particulate material storage bunker;

(b) means for regulating the operation of the feed conveyor for transporting the wet particulate material from the wet particulate material storage bunker to the dryer apparatus;

(c) means for regulating the delivery of the heat source to the heat exchanger, wherein the operative heat content delivered to the dryer apparatus by the heat source does not exceed 300°

F.;

(d) means for maintaining the particulate material within the dryer apparatus exposed to the heat source of a sufficient temperature and time duration to achieve the desired degree of moisture reduction to produce dried particulate material;

(e) means for regulating operation of a discharge gate on the dryer apparatus for controlling the discharge of the dried particulate material from the dryer apparatus; and

(f) means for regulating the operation of the discharge conveyor for transporting the dried particulate material from the dryer apparatus to the dried particulate material discharge destination.

20. The controller system of claim 19, wherein the temperature delivered to the dryer apparatus by the heat source is 200-300°

F.

32. A system for controlling the operation of a low-temperature, open-air process for heat treating a feed, by-product, or product stream within a plant operation that produces at least two different types of waste heat, wherein such process incorporates a source of feed, by-product or product stream, a heat apparatus, a first heat exchanger operatively connected to the heat apparatus, and a first waste heat source provided to the first heat exchanger for delivering heat content contained within the first waste heat source to the heat apparatus, a second heat exchanger operatively connected to the heat apparatus, a second waste heat source provided to the second heat exchanger for delivering heat content contained within the second waste heat source to the heat apparatus, such controller system comprising:

(a) means for regulating delivery of the feed, by-product, or product stream to the heat apparatus;

(b) means for regulating the delivery of the heat content contained within first waste heat source to the first heat exchanger;

(c) means for regulating the delivery of the heat content contained within the second waste heat source different in type from the first waste heat source to the second heat exchanger;

(d) means for actively combining predetermined amounts of heat content contained within the first waste heat source and second waste heat source to deliver an aggregate heat content to or within the heat apparatus;

(e) means for maintaining the feed, by-product, or product stream within the heat apparatus exposed to the aggregate heat content for a sufficient temperature and time duration to achieve the desired degree of heat treatment; and

(f) means for regulating delivery of the heated feed, by-product, or product stream discharged from the heat apparatus to a desired destination;

(g) wherein “

waste heat source”

means a fluid stream used in a plant operation having a heat content created by a process or a machine, which heat content is normally discarded after the heat content is created or the fluid stream is utilized to perform work.

44. The controller system of claim 32, wherein the active combining of the first waste heat source and the second waste heat source occurs inside a mixing box positioned outside the heat apparatus.

45. The controller system of claim 32, wherein the active combining of the first waste heat source and the second waste heat source occurs within two heat exchangers positioned in series outside the heat apparatus.

46. The controller system of claim 32, wherein the active combining of the first waste heat source and the second waste heat source occurs within a common heat exchanger positioned inside the heat apparatus.

33. A system for controlling the operation of a low-temperature, open-air process for thermally amplifying a gaseous stream for use in association with a heat treatment apparatus contained within a manufacturing operation that produces at least one waste heat source, wherein such process incorporates a gaseous stream and at least one waste heat source, such controller system comprising:

(a) means for regulating delivery of the gaseous stream at a first temperature;

(b) means for regulating the delivery of the waste heat source to a first heat exchanger whereby heat content contained within the waste heat source is delivered via the first heat exchanger to the gaseous stream which exits the first heat exchanger at a second temperature that is higher than the first temperature;

(c) means for regulating the delivery of a waste heat source to a second heat exchanger whereby heat content contained within the waste heat source is delivered via the second heat exchanger to the gaseous stream which exits the second heat exchanger at a third temperature that is higher than the second temperature;

(d) means for regulating delivery of the gaseous stream heated in series via the first heat exchanger and second heat exchanger to the heat treatment apparatus; and

(e) wherein “

waste heat source”

means a gaseous or liquid stream having an elevated heat content resulting from operation of a process or piece of equipment used within an industrial plant operation different from the dryer apparatus, such gaseous or liquid stream being used for the secondary purpose of providing heat content to the particulate material moisture reduction process.

34. The controller system of claim 33, wherein the waste heat source delivered to the first heat exchanger and the second heat exchanger constitute the same waste heat source within the manufacturing operation.

35. The controller system of claim 33, wherein the waste heat sources delivered to the first heat exchanger and the second heat exchanger constitute different types of waste heat sources within the manufacturing operation.

36. The controller system of claim 33, wherein the waste heat sources are selected from the group consisting of hot condenser cooling water, hot stack gas, hot flue gas, spent process steam, and discarded heat from operating equipment.

37. The controller system of claim 33 further comprising the providing of at least one additional heat exchanger and associated source of heat, whereby the gaseous stream exits the additional heat exchanger at a temperature higher than the temperature at which it exited the previous heat exchanger.

38. The controller system of claim 33, wherein the manufacturing operation is an electrical power plant.

39. A system for controlling the operation of a coal drying system incorporated into an industrial plant operation having at least two different types of waste heat, wherein such process incorporates a source of wet coal particulate material, a fluidized bed dryer, a fluidizing air stream, an air preheater for heating the fluidizing air stream before it enters the fluidized bed dryer, a heat exchanger embedded inside the fluidized bed dryer, a first waste heat source, and a second waste heat source different in type from the first waste heat source, such controller system comprising:

(a) means for regulating delivery of the coal particles to the fluidized bed dryer;

(b) means for regulating delivery of the air stream to the fluidized bed dryer to fluidize the coal particles within the dryer unit;

(c) means for regulating the delivery of the first waste heat source to the air preheater whereby heat content contained within the first waste heat source is delivered to the air preheater;

(d) means for regulating the delivery of the second waste heat source different in type from the first waste heat source to the air preheater whereby heat content contained within the second waste heat source is delivered to the air preheater;

(e) means for maintaining the fluidizing air stream within the air preheater for a sufficient time to elevate it to a desired temperature before the fluidizing air stream is delivered to the fluidized bed dryer;

(f) means for regulating the delivery of at least one of the waste heat sources to the heat exchanger embedded inside the fluidized bed dryer for increasing the interior temperature of the dryer unit;

(g) means for maintaining the coal particles within the dryer unit exposed to a combination of the heat content contained within fluidizing air stream and provided by the embedded heat exchanger for a sufficient temperature and time duration to achieve the desired degree of moisture reduction to the coal particles;

(h) means for regulating delivery of the moisture-reduced coal particles discharged from the fluidized bed dryer to a moisture-reduced coal particles discharge destination; and

(i) wherein “

waste heat source”

means a gaseous or liquid stream having an elevated heat content resulting from operation of a process or piece of equipment used within an industrial plant operation different from the dryer apparatus, such gaseous or liquid stream being used for the secondary purpose of providing heat content to the particulate material moisture reduction process.

40. The controller system of claim 39, wherein the two different types of waste heat sources constitute hot condenser cooling water and hot flue gas produced within the industrial plant operation.