Method of operating a solar thermal process heat plant and solar thermal process heat plant

• US 20080184789A1
• Filed: 01/23/2008
• Published: 08/07/2008
• Est. Priority Date: 01/24/2007
• Status: Abandoned Application

• Current Assignee: Deutsches Zentrum Fã¼R Luft- Und Raumfahrt E.V.
• Original Assignee: Deutsches Zentrum Fã¼R Luft- Und Raumfahrt E.V.
• Inventors: Hirsch, Tobias, Eck, Markus, Koch, Stephan
• Application Number:
  US12/011,033
• Publication Number:
  US 20080184789A1
• Time in Patent Office: Days
• US Class Current: 73/204.16
• CPC Class Codes: F03G 6/065 having a Rankine cycle
• CPC Class Codes: F22B 1/006 using solar heat solar heat collectors per se F24S; devices for producing mechanical power from solar energy F03G6/00
• CPC Class Codes: F22B 35/16 responsive to the percentage of steam in the mixture of steam and water
• CPC Class Codes: F24S 50/00 Arrangements for controlling solar heat collectors
• CPC Class Codes: Y02E 10/46 Conversion of thermal power into mechanical power, e.g. Rankine, Stirling or solar thermal engines

Abstract

There is proposed a method of operating a solar thermal process heat plant, in which a heat carrier medium is heated in a heating section by solar radiation, wherein the heating section comprises a plurality of heating branches, among which the heat carrier medium is distributed, comprising measuring at heating branches a state variable of the heat carrier medium, respectively, calculating a mean value of measured state variables over heating branches, and controlling mass flow control valves in the respective heating branches in dependence upon the respective deviation between the measured state variable of the flowing heat carrier medium in the respective heating branch and the calculated mean value.

Claims

1. Method of operating a solar thermal process heat plant, in which a heat carrier medium is heated in a heating section by solar radiation,

wherein the heating section comprises a plurality of heating branches, among which the heat carrier medium is distributed, comprising:

measuring at heating branches a state variable of the heat carrier medium, respectively;

calculating a mean value of measured state variables over heating branches; and

controlling mass flow control valves in the respective heating branches in dependence upon the respective deviation between the measured state variable of the flowing heat carrier medium in the respective heating branch and the calculated mean value.

2. Method according to claim 1, wherein precisely one mass flow control valve is provided per heating branch.

3. Method according to claim 1, wherein the heat carrier medium as it flows through the heating section is gaseous or vaporous or liquid or a multiphase mixture.

4. Method according to claim 1, wherein heat carrier medium is split from a basic flow into parallel partial flows, wherein the respective partial flows flow through respective heating branches.

5. Method according to claim 1, with a control circuit associated with the heating section, in which adjusted variables are valve settings of the mass flow control valves and controlled variables are the respective state variables of the heat carrier medium in the respective heating branches.

6. Method according to claim 5, wherein a target variable for the controlled variables is the mean value of the state variables.

7. Method according to claim 5, wherein the control circuit comprises PI controllers, which are associated with the respective heating branches and by means of which the mass flow control valves are controlled.

8. Method according to claim 1, wherein the state variables at different heating branches are measured at mutually corresponding points of the heating branches.

9. Method according to claim 1, wherein at the respective heating branch the state variable of the flowing heat carrier medium is measured at or in the vicinity of an outlet of a solar collector device.

10. Method according to claim 1, wherein at the respective heating branch the state variable of the flowing heat carrier medium is measured downstream of a penultimate solar collector device.

11. Method according to claim 1, wherein at the respective heating branch the state variable of the flowing heat carrier medium is measured at or in the vicinity of an outlet end of the heating branch.

12. Method according to claim 1, wherein mass flow control is carried out in the heating branches without mass flow measurement.

13. Method according to claim 1, wherein the mass flow control valves are started in an initial position, in which the valve setting is a partial lift of a possible complete lift or a complete lift.

14. Method according to claim 1, wherein the state variable is the temperature of the heat carrier medium.

15. Method according to claim 1, wherein the state variable is the vapour content in the heat carrier medium when the heat carrier medium is multiphase.

16. Method according to claim 1, wherein at one or more heating branches the mass flow is reduced by means of at least one restrictor.

17. Method according to claim 16, wherein the respective at least one restrictor is disposed at or in the vicinity of a single-phase flow region of the associated heating branch.

18. Method according to claim 1, wherein at the respective heating branch fluid heat carrier medium is injected.

19. Method according to claim 18, wherein by means of the injection the state variable and/or a final temperature of the heat carrier medium on leaving the heating branch is controlled.

20. Method according to claim 18, wherein the injection is carried out upstream of a last solar collector device of the heating branch.

21. Method according to claim 20, wherein the injection is effected after the measurement of the state variable that is included in the mean-value generation.

22. Method according to claim 18, wherein the injection is carried out by means of a control circuit.

23. Method according to claim 22, wherein a controlled variable of the control circuit is the state variable of the heat carrier medium and a manipulated variable is an injection quantity.

24. Method according to claim 1, wherein the closed-loop control is carried out in such a way that a mass flow control valve under stationary conditions has a defined setting.

25. Method according to claim 1, wherein the respective heating branch comprises one or more solar collector devices.

26. Method according to claim 25, wherein the at least one solar collector device takes the form of a focal-line collector.

27. Method according to claim 1, wherein the at least one solar collector device is a tower receiver device or a segment of a tower receiver device.

28. Method according to claim 1, wherein the heating section is a superheating section for vaporous heat carrier medium.

29. Method according to claim 1, wherein the total flow of heat carrier medium that is supplied to the heating section is supplied by one or more liquid-vapour separators.

30. Solar thermal process heat plant, comprising:

a heating section, in which a heat carrier medium is heatable by solar radiation;

wherein the heating section comprises a plurality of heating branches connected in parallel;

wherein at the heating branches or a majority of the heating branches a mass flow control valve is disposed, respectively;

one or more state variable sensors for measuring a state variable of flowing heat carrier medium associated with the heating branches, respectively;

a control device, by means of which the mass flow control valves are controllable; and

a mean-value generating device, by means of which a mean value of measured state variables over heating branches is calculable;

wherein the control of the mass flow control valve of a respective heating branch is dependent upon the state variable deviation between the respective measured state variable of the heat carrier medium in the respective heating branch and the calculated mean value over the heating branches.

31. Solar thermal process heat plant according to claim 30, wherein inputs of the mean-value generating device are connected to state variable sensors.

32. Solar thermal process heat plant according to claim 30, wherein outputs of the mean-value generating device are connected to controllers associated with the heating branches.

33. Solar thermal process heat plant according to claim 30, wherein the state variable sensors are temperature sensors.

34. Solar thermal process heat plant according to claim 30, wherein the state variable sensors are vapour content sensors.

35. Solar thermal process heat plant according to claim 30, with a distribution device for splitting a total flow into partial flows for flowing through the heating branches.

36. Solar thermal process heat plant according to claim 30, wherein one or more liquid-vapour separators are disposed upstream of the distribution device.

37. Solar thermal process heat plant according to claim 30, wherein a liquid-vapour separator is a central separator that is associated with a plurality of evaporator branches.

38. Solar thermal process heat plant according to claim 37, wherein the liquid-vapour separator is a separator of a recirculation device of the evaporator branches.

39. Solar thermal process heat plant according to claim 30, wherein the state variable sensors of different heating branches are disposed at mutually corresponding points.

40. Solar thermal process heat plant according to claim 30, wherein a state variable sensor of a heating branch is disposed downstream of an output of a penultimate solar collector device.

41. Solar thermal process heat plant according to claim 40, wherein a state variable sensor is disposed on a heating branch at or in the vicinity of an outlet end of the heating branch.

42. Solar thermal process heat plant according to claim 30, with a first control circuit, by means of which the mass flow control valves is controllable.

43. Solar thermal process heat plant according to claim 30, wherein at least one injection device having one or more injection points for fluid heat carrier medium is associated with a heating branch.

44. Solar thermal process heat plant according to claim 43, wherein the at least one injection device comprises at least one controller, by means of which a second control circuit is formed, by means of which the injection of fluid heat carrier medium is controllable.

45. Solar thermal process heat plant according to claim 43, wherein an injection point of a respective heating branch is disposed downstream of a state variable sensor of the heating branch that supplies state variable values for the mean-value generation.

46. Solar thermal process heat plant according to claim 43, wherein an injection device comprises a valve for controlling the injection quantity of fluid heat carrier medium.

47. Solar thermal process heat plant according to claim 43, wherein an output of the valve is disposed upstream of an input of a solar collector device.

48. Solar thermal process heat plant according to claim 43, wherein the injection device comprises at least one of a state variable sensor and a temperature sensor.

49. Solar thermal process heat plant according to claim 48, wherein the state variable sensor is disposed downstream of an output of a solar collector device.

50. Solar thermal process heat plant according to claim 43, wherein the injection device is associated with a last solar collector device of the heating branch.

51. Solar thermal process heat plant according to claim 30, wherein one or more heating branches has at least one restrictor.

52. Solar thermal process heat plant according to claim 30, wherein a heating branch has a plurality of solar collector devices.

53. Solar thermal process heat plant according to claim 52, wherein the solar collector devices are focal-line collectors.

54. Solar thermal process heat plant according to claim 30, wherein the heating section is at least partially arranged on a tower receiver.

55. Solar thermal process heat plant according to claim 30, wherein the plant is a solar thermal power plant.

56. Solar thermal process heat plant according to claim 55, wherein a generator device for the generation of electrical energy is provided.

57. Solar thermal process heat plant according to claim 30, wherein the plant is a steam generator plant.