Method and Device for Gas Purification by Means of Partial Condensation, and Method for Operating the Device

• US 20110030421A1
• Filed: 10/29/2007
• Published: 02/10/2011
• Est. Priority Date: 11/10/2006
• Status: Active Grant

• Current Assignee: L'Air Liquide Societe Anonyme Pour L'Etude et L'Exploitation Des Procedes Georges Claude (L'Air Liquide SA)
• Original Assignee: L'Air Liquide Societe Anonyme Pour L'Etude et L'Exploitation Des Procedes Georges Claude (L'Air Liquide SA)
• Inventors: Stahl, Manfred, Kutz, Thomas
• Granted Patent: US 9,089,808 B2
• Time in Patent Office: Days
• US Class Current: 62/532
• CPC Class Codes: B01D 5/0015 Plates
• CPC Class Codes: B01D 53/002 by condensation
• CPC Class Codes: B01D 7/02 Crystallisation directly from the vapour phase into single crystals C30B23/00
• CPC Class Codes: F28D 7/0066 Multi-circuit heat-exchangers, e.g. integrating different heat exchange sections in the same unit or heat-exchangers for more than two fluids F28D7/103 takes precedence
• CPC Class Codes: F28D 7/1607 with particular pattern of flow of the heat exchange media, e.g. change of flow direction F28D7/1623, F28D7/1638, F28D7/1661, F28D7/1676, F28D7/1692 take precedence

Abstract

The subject matter of the invention is a method for purifying a foreign-substance-laden gas flow of the foreign substance, with the gas flow being conducted through a heat exchanger and being placed in thermal contact with a cooling medium in order to freeze and/or condense the foreign substance out, wherein the purification takes place in only one tube heat exchanger, through the interior space of which the gas flow is conducted from a first end region to a second end region, and here, is cooled by means of contact with a first group of tubes which are traversed by the coolant, and in that the gas flow, in the second end region, is directly deflected again and is conducted back through the interior space of the heat exchanger to the first end region through a second group of tubes while undergoing an exchange of heat with the gas flow flowing into the interior space. A corresponding device has a heat exchanger having at least two groups of tubes which run through an interior space of the heat exchanger from a first end region to a second end region of the heat exchanger, with it being possible for the gas flow to traverse the interior space of the heat exchanger from a gas flow inlet at the first end region to the second end region, and with a first group of the tubes being part of a substantially closed cooling medium circuit, and a second group of the tubes for recirculating the gas flow from the second end region of the heat exchanger being connected to a purified gas outlet in the first end region. In order to further reduce the operating temperature in the second end region, it is possible for additional cooling medium to be injected into the cooling medium circuit upstream of said second end region. It is even possible for the injection to take place by means of an injector, which then replaces a pump and cooler.

Claims

1-27. -27. (canceled)

28. Method for purifying a foreign-substance-laden gas flow of the foreign substance, with the gas flow being conducted through a heat exchanger and being placed in thermal contact with a cooling medium in order to freeze and/or condense the foreign substance out, characterized in that the purification takes place in only one tube heat exchanger, through the interior space of which the gas flow is conducted from a first end region to a second end region, and here is cooled by way of contact with a first group of tubes which are traversed by the coolant, and in that the gas flow, in the second end region, is directly deflected again and is conducted back through the interior space of the heat exchanger to the first end region through a second group of tubes while undergoing an exchange of heat with the gas flow flowing into the interior space.

29. The method of claim 28, wherein the cooling medium is guided substantially in a closed circuit, with said cooling medium being cooled to a predefined temperature by a primary coolant before entering the second end region of the heat exchanger.

30. The method of claim 29, wherein the cooling takes place in a cooler.

31. The method of claim 30, wherein a liquid gas is conducted as a primary coolant to the cooler, which liquid gas, in an exchange of heat, cools the cooling medium which is guided substantially in a closed circuit.

32. The method of claim 31, wherein the primary coolant is guided in an open circuit.

33. The method of claim 29, wherein the primary coolant is injected into the substantially closed circuit by an injector.

34. The method of claim 33, wherein the primary coolant is injected by an injector with such a level of kinetic energy that a flow is thereby maintained in the substantially closed circuit, in particular without the use of a pump.

35. The method of claim 28, wherein the cooling medium in the first group of tubes and the recirculated gas flow in the second group of tubes cool the gas flow in the interior space of the heat exchanger in counterflow.

36. The method of claim 28, wherein an additional quantity of liquid cooling medium is supplied to the second end region of the heat exchanger in order to reduce an operating temperature there.

37. The method of claim 28, wherein all the cooling media of the entire system are identical and in that primary cooling medium is injected into the second end region upstream of the inlet.

38. The method of claim 37, wherein the cooling medium which traverses the tube heat exchanger being guided in a substantially closed circuit, from which primary cooling medium, which is injected into the heat exchanger upstream of the inlet, is discharged again downstream of the heat exchanger.

39. The method of claim 33, wherein the injected quantity of primary cooling medium makes up between 5 and 20% of the quantity of cooling medium which traverses the heat exchanger per unit time.

55. The method of claim 31, wherein the liquid gas is liquid nitrogen or liquid carbon dioxide.

56. The method of claim 37, wherein the cooling media is nitrogen or carbon dioxide.

57. The method of claim 39, wherein the injected quantity of primary cooling medium makes up between 10 and 15% of the quantity of cooling medium which traverses the heat exchanger per unit time.

40. A device for purifying a foreign-substance-laden gas flow of the foreign substance, with the gas flow being conducted through a heat exchanger and being placed in thermal contact with a cooling medium in order to freeze and/or condense the foreign substance out, characterized in that a tube heat exchanger is provided as a heat exchanger, having at least two groups of tubes which run through an interior space of the heat exchanger from a first end region to a second end region of the heat exchanger, with it being possible for the gas flow to traverse the interior space of the heat exchanger from a gas flow inlet at the first end region to the second end region, and with a first group of the tubes being part of a substantially closed cooling medium circuit, and a second group of the tubes for recirculating the gas flow from the second end region of the heat exchanger being connected to a purified gas outlet in the first end region.

41. The device of claim 40, wherein the second end region of the heat exchanger is embodied as a deflection for the gas flow into the second group of tubes.

42. The device of claim 40, wherein the cooling medium circuit has a delivery device and a cooler which is traversed by primary coolant and which is arranged upstream of the second end region of the heat exchanger.

43. The device of claim 42, wherein the cooler is connected to an open or closed primary coolant circuit.

44. The device of claim 40, wherein the substantially closed cooling medium circuit has, as viewed in its throughflow direction, an additive inlet for an additional quantity of cooling medium upstream of the inlet into the second end region of the heat exchanger, and an additive outlet for the additional quantity of cooling medium downstream of the first end region of the heat exchanger.

45. The device of claim 40, wherein an injector for additional cooling medium of a two-phase mixture and an additive outlet for the additional cooling medium are provided in series in the flow direction in the substantially closed cooling medium circuit, between which injector and additive outlet is situated the heat exchanger.

46. The device of claim 44, wherein adjusting devices for controlling or regulating the inlet and the outlet with regard to additional cooling medium are provided.

47. The device of claim 40, wherein the heat exchanger is arranged with a gradient in the direction of the throughflow of cooling medium of less than 10°

with respect to the horizontal.

48. The device of claim 40, wherein the heat exchanger has two or more condensate outflows on its underside which are arranged at intervals in series in the direction of the throughflow with cooling medium.

49. The device of claim 40, wherein the heat exchanger is provided at least with a first measuring sensor for measuring a measurement value from which the temperature of the gas flow in the second end region of the heat exchanger can be derived.

50. The device of claim 40, wherein at least one actuating element is provided in the cooling medium circuit and/or one is provided in the coolant circuit, which actuating elements are connected to a process regulator, so that the refrigerating power supplied to the heat exchanger can be regulated.

51. The method for regulating a device of claim 40, wherein a measurement value which is proportional to the temperature of the gas flow in the second end region of the heat exchanger is measured and adjusted in a regulated fashion to a predefined nominal value, by virtue of the throughflow and/or the temperature in the cooling medium circuit being correspondingly adapted.

52. The method of claim 51, wherein a process regulator processes the measurement value and activates a delivery device in the cooling medium circuit and/or a regulating valve in the coolant circuit as actuating elements so as to keep the measurement value constant.

53. The method of claim 52, wherein substantially the temperature in the cooling medium circuit upstream of the heat exchanger is regulated by the regulating valve in the coolant circuit, and substantially the temperature in the cooling medium circuit downstream of the heat exchanger is regulated by the delivery device.

54. The method of claim 51, wherein the supply of coolant into the cooling medium circuit is regulated by an injector, a temperature in the cooling medium circuit upstream of the heat exchanger being regulated by the quantity of supplied coolant, a temperature in the cooling medium circuit downstream of the heat exchanger being regulated by a speed of the supplied coolant and/or the type of supply.

58. The device of claim 43, wherein the primary coolant is liquid nitrogen or carbon dioxide.