SYSTEM AND METHOD FOR CRYOGENIC CONDENSING

Abstract

A method and apparatus for condensing vapor in a gas. A cryogen, such as liquid nitrogen, may be provided into first and second coil sets in a condenser housing to cool the condensable vapor in the housing to condense the vapor into a liquid or solid form. The flow of cryogen in the first and second coil sets may be independently controlled, coils in the first and/or second coil sets may have a substantially equal length, and/or coils in the first and/or second coil sets may have uppermost portions that are located at a substantially equal height.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. provisional application Ser. Nos. 61/498,869 filed Jun. 20, 2011, the disclosure of which are incorporated by reference herein.

FIELD OF THE INVENTION

The present invention relates to methods and systems for removing a condensable vapor, such as water vapor, from a gas, and more particularly, to a cryogenic condenser.

BACKGROUND

Cryogenic condenser systems for removing condensable vapor from a gas such as those describes in U.S. Pat. No. 6,505,472 are generally known in the art. In some applications, particularly freeze-drying applications that use alcohol base formulations, very low condensation temperatures are required (i.e. colder than −100 C and lower than the freezing point of most heat transfer fluids).

Freeze drying is a sublimation process that removes water from a product in the form of ice. Freeze drying is especially useful in the pharmaceutical industry to remove water from biological products because it preserves the integrity of the biological products. In freeze drying, the water-containing or alcohol containing product is frozen and, under vacuum with the partial pressure of water vapor reduced below the triple point of water, the frozen water sublimes and the sublimated ice is removed from the dryer.

Accordingly, what is needed is an improved cryogenic condensing system and method for effectively removing a condensable vapor, such as water vapor, from a gas stream and which can operate efficiently and effectively at very low or cryogenic temperatures often seen during freeze drying cycles. Ideally, the cryogenic condensing system should be able to handle large thermal cycling in a freeze drying process without stress cracking caused by thermal expansion and contraction.

SUMMARY OF INVENTION

Aspects of the invention relate to systems and methods for condensing or otherwise removing a condensable vapor from a gas stream, such as a gas stream used to effect a freeze drying process. In one embodiment, a gas stream, such as a nitrogen gas stream containing condensable water vapor, is provided to a cryogenic condenser that includes two or more coils that carry a cryogen, such as liquid nitrogen or other similar material. By passing the gas stream across/near the coils, the coils may remove heat from the gas stream, causing the condensable vapor in the gas stream to condense into liquid and/or solid form. Thereafter, the condensed vapor may be removed from the condenser, and the gas, now having a reduced amount of condensable vapor, exhausted.

In one embodiment, the two or more coils of the condenser may have a substantially equal length from an inlet to an outlet. This feature may permit the coils to operate in removing condensable vapor in a more uniform way, e.g., the coils may operate at the same or similar rate in generating condensate, may carry similar amounts of cryogen, and/or have other similar operating characteristics that allow the condenser to operate more efficiently.

In another embodiment, the coils may have uppermost portions that are located at a substantially equal height relative to each other. This arrangement may allow the coils to experience a same fluid pressure of cryogen carried in the coils, e.g., due to the force of gravity, in the coils, and thus the coils may have the same or similar cryogen flow rates. This may help the coils to operate in the same, or substantially the same, way with respect to condensate production.

In yet another embodiment, the cryogen flow in the coils may be independently controllable. Such an arrangement may permit the condenser to continue operation even if one coil fails or otherwise stops proper operation. For example, if a first coil begins to leak cryogen, the first coil may be shut down (such as by stopping cryogen supplied to the coil) while a second coil continues to operate.

In one embodiment, a cryogenic condenser includes a housing defining an interior space with a gas inlet for introducing gas with a condensable vapor into the interior space and a gas outlet for exhausting gas. First and second coil sets may be located in the interior space, with each of the coil sets including at least one coil having an inlet and an outlet and arranged to conduct a cryogen from the inlet to the outlet. The coils may therefore be arranged to cool the condensable vapor in the interior space to condense the vapor into a liquid or solid form. A cryogen supply including at least one valve may be arranged to independently control flow of cryogen in each of the coils and/or coil sets. Coils of the first and second sets, or coils within at least one of the sets, may have a substantially equal length from the inlet to the outlet, and/or may have uppermost portions that are located at a substantially equal height relative to each other.

In one embodiment, the condenser housing may define a cylindrical space having a top and a bottom, and a first of the coil sets may be located above a second of the coil sets in the interior space. Alternately, the coils may be nested or be arranged side-by-side. The housing may have the gas inlet arranged at a side of the cylindrical space and the gas outlet arranged at the top of the cylindrical space. An inlet baffle may be arranged at the gas inlet to direct gas toward the bottom of the cylindrical shape, and/or other baffles may be provided, e.g., at the top or bottom of the cylindrical space, to direct gas flow in the interior space in a vertical direction.

In one embodiment, each of the coil sets includes at least four coils that have a substantially equal length and that are arranged in a nested form. The coils of each set may be provided with cryogen from a common conduit. Cryogen exhausted from the outlets of the coils may be removed from the condenser via a common cryogen outlet.

In another aspect of the invention, a method for removing condensate from a gas stream includes providing a gas with a condensable vapor into a condenser housing, providing a liquid cryogen into first and second coil sets in the condenser housing to cool the condensable vapor in the interior space to condense the vapor into a liquid or solid form in the condenser housing, and independently controlling a flow of liquid cryogen in the first and second coil sets. Independent control of flow of cryogen for the coil sets may be performed by operating at least one valve for a first cryogen supply for the first coil set independently of operation at least one valve for a second cryogen supply for the second coil set. The first and second coil sets may each include first and second coils, each having an inlet and an outlet and arranged to conduct a cryogen from the inlet to the outlet. The first and second coils may be nested with the second coil being at least partially surrounded by the first coil, and the first and second coils each having a substantially equal length and/or an uppermost portion that are located at a substantially equal height. Each of the first and second coil sets may include at least a third coil that is nested with the first and second coils, with the third coil having a substantially equal length as the first and second coils and/or an uppermost portion that is located at a substantially equal height at the uppermost portions of the first and second coils. Liquid cryogen may be provided to the first, second and third coils of each coil set with liquid cryogen from a common conduit, and the first coil set may be positioned above the second coil set.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of the present invention will be more apparent from the following, more detailed description thereof, presented in conjunction with the following drawings, wherein:

FIG. 1 is a perspective view of a cryogenic condenser in an illustrative embodiment;

FIG. 2 shows an upper right side perspective view of an embodiment of a cryogenic condenser that is similar to that shown in FIG. 1;

FIG. 3 is a lower left side perspective view of the FIG. 2 embodiment;

FIG. 4 is a front view of the FIG. 2 embodiment;

FIG. 5 is a right side view of the FIG. 2 embodiment;

FIG. 6 shows a cross sectional view along the line 6-6 as shown in FIG. 5;

FIG. 7 shows a cross sectional view along the line 7-7 as shown in FIG. 4;

FIG. 8 shows a side view of the first coil set of the FIG. 2 embodiment;

FIG. 9 shows a top view of the first coil set of the FIG. 2 embodiment;

FIG. 10 shows a cross sectional view along the line 10-10 in FIG. 9; and

FIG. 11 shows a perspective view of the coil set of FIGS. 8-10.

DETAILED DESCRIPTION

It should be understood that illustrative embodiments are described in accordance with aspects of the invention. However, the embodiments described are not necessarily intended to show or incorporate all aspects of the invention, but rather are used to describe a few illustrative embodiments. Thus, aspects discussed herein are not intended to be construed narrowly in view of the illustrative embodiments. In addition, it should be understood that aspects of the invention described may be used alone or in any suitable combination with other aspects also described.

FIG. 1 shows an illustrative embodiment of a cryogenic condenser 1 that incorporates one or more aspects of the invention. In this embodiment, the condenser 1 includes a housing 10 that defines an interior space that has a cylindrical shape. However, it should be understood that the housing 10 may have any suitable shape, size or other arrangement, and may define an interior space having any suitable size or shape, such as a box shape, a spherical shape, etc. The housing 10 includes a gas inlet 11 through which a gas having a condensable vapor (such as air or nitrogen gas including water vapor) may be introduced into the housing 10. In this embodiment, the gas inlet 11 is arranged at a side of the housing 10, but may be located at any suitable location or locations, such as the top, bottom, and/or side(s) of the housing 10. The housing 10 also includes a gas outlet 12 through which gas may exit the housing 10, e.g., after having at least some condensable vapor removed. In this embodiment, the gas outlet 12 is arranged at the top of the housing 10, but may be arranged at the bottom, side(s) and/or the top, as desired. (Although portions of housing 10 are referred to as being a top, bottom, or side, these references are for convenience and do not necessarily require that the condenser 1 be used in any particular orientation. For example, condenser 1 may be used so that gas outlet 12 at the “top” is arranged at a position that is below, or at a same height, as gas inlet 11, e.g., with housing 10 tilted so that both the gas flow at inlet 11 and outlet 12 are generally in a horizontal plane.)

The condenser 1 includes first and second coil sets 13a, 13b (which may each include one or more coils) in the interior space of the housing that are arranged to cool the condensable vapor so as to condense the vapor into a liquid or solid form, e.g., for removal from the gas provided at the gas inlet 11. For example, in some applications, it may be desired to remove water vapor from a gas stream (e.g., including mostly air or nitrogen gas). The coils sets 13a, 13b may be arranged to cool the water vapor so as to cause the water vapor to condense into liquid or solid water (e.g., water droplets or ice). Once condensed into liquid and/or solid form, the water may be removed, e.g., via a condensate outlet 14 (e.g., a pipe or opening in the housing 10) located at a bottom of housing 10. If the condensable vapor is condensed into solid form, the ice or other solid may be removed from housing 10 in any suitable way, such as by scraping coils sets 13 to remove the solid, which is then removed by a conveyor belt, falling through a condensate outlet 14 opening in housing 10. Alternately, coil sets 13 may be heated (or the solid ice otherwise heated) to change the condensate to a liquid form or otherwise cause the solid to be removed from coil sets 13, which may then fall from coils sets 13 for removal.

In accordance with one aspect of the invention, one or more coils in the coil sets may have a length from an inlet to an outlet that is the same or substantially the same. That is, a length of a coil in the first coil set 13a may be equal or substantially equal to a length of a coil in the second coil set 13b, and/or a length of a coil in the first coil set 13a may be equal or substantially equal to a length of another coil in the first coil set 13a. In this context, the length of a coil from the inlet to the outlet is the length of a region of the coil between the inlet and the outlet where the coil functions to remove heat from gas in the housing 10 to help cause condensation of the condensable vapor. By having the length of the coils be the same or substantially the same, the coils may remove heat from the interior space at a same or similar rate, may produce condensate at a same or similar rate, may carry a same or similar amount of cryogen or other cooling substance, and/or have other similar operating characteristics. Having the coils (or at least some coils) in the housing 10 operate with the same or similar condensate forming characteristics, the condenser 1 may operate more efficiently and/or effectively. For example, equal length coils may carry a same volume and/or flow rate of cryogen, and thus share the same or similar cooling rate, condensate generation or other characteristics, helping to avoid one coil being colder or warmer (on average) than another. Avoiding such an imbalance may help avoid excessive ice production on one coil versus another, and/or undesirably low condensate production by one coil versus another.

Accordingly, in one aspect of the invention, one coil set, such as the first coil set 13a, may include two or more coils that have a same or substantially the same length from inlet to outlet as each other. In another embodiment, one or more coils in one coil set (such as the first coil set 13a) may have the same or substantially the same length as one or more coils in the other coil set (such as the second coil set 13b). The coils may be stacked one on the other, e.g., as shown for the coil sets 13a, 13b in FIG. 1, may be nested one inside the other (as discussed in more detail below where one outer coil at least partially surrounds another inner coil), or have another suitable arrangement, such as side-by-side positioning.

In another aspect of the invention, the cryogen supply for the coil sets in a condenser may be individually controlled. Such an arrangement may permit the condenser to continue operation, albeit at a potentially lower output (e.g., a lower condensate output), if one of the coil sets fails or otherwise stops proper operation. For example, if the first coil set 13a in the FIG. 1 arrangement begins to leak cryogen, the first coil set 13a may be shut down (such as by stopping cryogen supplied to the coil set 13a) while the second coil set 13b continues to operate. Continued operation of a condenser may be important in some operations, such as where the condenser is involved in removing vapor as part of a batch treatment process that cannot be stopped without causing damage to the product being treated (such as a food product) or otherwise incurring loss. Thus, the condenser may be enabled to continue operation to complete a batch and repaired after processing of the batch of product is complete. As shown in FIG. 1, the first and second coil sets 13a, 13b each have respective cryogen supply conduits 14a, 14b that are part of a cryogen supply. The cryogen supply may also include valves 20a, 20b for each of the conduits 14a, 14b or other suitable arrangements for controlling the flow of cryogen to the coil sets 13a, 13b. Of course, flow of cryogen to a coil set 13 may be controlled in other ways, such as by controlling operation of a pump, insertion of a plug or other stop in the conduit 14, and/or in other ways. As discussed above, this aspect of the invention may be used with respect to coils in a set that are stacked as shown in FIG. 1, nested, arranged in a side-by-side fashion, and/or in other ways.

Another aspect of the invention shown in FIG. 1 is that the condenser housing 10 includes the gas inlet 11 at a side of the housing arranged so that gas enters the housing 10 in a generally horizontal direction, and the gas outlet 12 is arranged at a top of the housing 10 so that gas exits the housing 10 in a generally vertical direction. Thus, in one aspect of the invention, gas may enter the housing 10 of the condenser 1 in a direction that is generally transverse, e.g., perpendicular, to a direction in which gas exits the housing 10. In addition, the condenser 1 may include an inlet baffle 15 arranged at the gas inlet 11 to direct gas toward the bottom of the housing 10, as well as potentially toward a side of the housing 10 opposite the gas inlet 11. In this embodiment, the inlet baffle 15 is arranged as a curved sheet, but may take any suitable form, including one or more flat plates, fins, conduits, etc. The condenser 1 may also include one or more baffles 16 near a bottom of the housing 10, e.g., to generally direct gas flow upwards and toward the coil sets 13. In this embodiment, one baffle 16 is located between a bottom of the housing 10 and the second coil set 13b toward a side of the housing that is offset from the gas inlet 11. Of course, two or more baffles or other elements could be used to influence gas flow, and could be arranged in any suitable way. This embodiment also includes two baffles 17 near a top of the housing 10. These baffles 17 may function to generally direct gas flow toward the gas outlet 12, and/or to inhibit flow of gas from the gas inlet 11 from “short circuiting” to the gas outlet 12. For example, a forward baffle 17a may be arranged to help prevent gas entering at the gas inlet 11 from traveling upwardly, along the inlet baffle 15 and directly to the gas outlet 12. Again, the baffles 17 may be arranged in other suitable ways, and using other suitably configured elements.

FIG. 2 and FIG. 3 show a upper right side perspective view and a lower left side perspective view of an embodiment that is similar to that shown in FIG. 1. Like the FIG. 1 embodiment, the condenser 1 shown includes a housing 10 (shown in dashed line to reveal the internal components of the condenser 1) with a generally cylindrical shape, a gas inlet 11 at a side of the housing 11, and a gas outlet 12 at a top of the housing. A pair of coils sets 13a and 13b are also included, although in this embodiment each coil set 13 includes four coils that are nested. In accordance with an aspect of the invention, and as described in more detail below, the coils in each coil set 13 have a same or substantially same length, and have an uppermost portion that are at the same or substantially the same height, e.g., to help ensure similar cryogen flow rates in the coils. In addition, the coil sets 13 are individually controllable, i.e., a supply or flow of cryogen in the coils of each set may be controlled independent of each other, e.g., by controlling flow in the supply conduits 14a, 14b for the coil sets 13a, 13b. Although the coil sets 13 share a common cryogen outlet 18, the coil sets 13 may be provided with individual cryogen outlets 18, if desired.

FIGS. 4 and 5 show a front view and a right side view (i.e., a view from a side opposite of the gas inlet 11) of the condenser 1. As can be seen in FIGS. 4 and 5, the coils in each of the coil sets 13a, 13b have a different pitch, i.e., a different spacing between adjacent coil loops. That is, because the coils in each set 13 have a same length, the coils in the outer regions of the coil set 13 will have a greater pitch (larger distance between adjacent coils) than coils in the inner regions of the coil set 13. Support structure 22 may be used to help support the weight of the coils, as well as maintain a desired radial and/or axial location of the coils relative to each other. The support structure 22 may also allow the coils to expand (lengthen) and contract (shorten) in response to temperature changes or other causes. In this embodiment the support structure 22 includes vertically oriented bars that are connected together by horizontal stays at upper and lower ends of the housing 10, but other arrangements are possible.

To help illustrate the coil arrangement in the coil sets 13, FIGS. 6 and 7 show cross sectional views along the lines 6-6 and 7-7 as shown in FIGS. 5 and 4, respectively. For example, considering the first coil set 13a on the right side of FIG. 6, the outermost coil 5 includes six total loops, whereas the adjacent coil 4 has seven total loops. Stepping inwardly, the next coil 3 has eight total loops, and the innermost coil 2 has eleven total loops. As will be described in more detail below, the innermost coil 2 has two sets of coil loops—one inner set and one outer set. Because the innermost coil 2 has a relatively small diameter as compared to the more outer coils, the innermost coil 2 is provided with inner and outer coil loops to provide coil 2 with the same length as the other coils in the coil set 13a. Of course, the same coil length could be provided in other ways, such as by further reducing the pitch of coil loops in the coil 2.

As can also be generally seen in FIG. 6, the cryogen supply conduits 14a, 14b provide cryogen to a respective supply manifold near a bottom of the respective coil set 13a, 13b. The inlet of each coil in the set (e.g., coils 2, 3, 4 and 5 of the coil set 13a) is connected to the supply manifold. From the manifold, each coil 2, 3, 4, 5 extends upwardly to an uppermost portion (indicated generally at reference 19 in FIG. 6). From the uppermost portion, cryogen in the coils flows in a generally downward direction to an exhaust manifold near a bottom of the set 13 to which the outlet of the coils is connected. The exhaust manifold is connected to the cryogen outlet 18 so that cryogen may exit the condenser 1 after flowing through the coils.

FIG. 8 shows a side view and FIG. 9 shows a top view of the first coil set 13a from the FIGS. 2-7 embodiment. Although the coil sets 13 may be arranged differently from each other, in this embodiment, the coil sets 13a, 13b have substantially the same or identical arrangement. By arranging the coil sets 13a, 13b in the same way, the coils may perform in approximately the same way, e.g., have the same or similar condensate forming characteristics. As can be seen in FIG. 8, the cryogen supply conduit 14a is connected to the supply manifold 23 near a bottom of the coil set 13a. The inlets of the coils 2, 3, 4, 5 are connected to the supply manifold 23 and extend upwardly to an uppermost portion (indicated generally at reference number 19) from which each of the coils begin to have a coil loop shape that spirals generally downwardly toward the bottom of the coil set 13a. Thus, in one aspect of the invention, two or more coils in a coil set may have uppermost portions that are located at a same height. By having these uppermost portions located at approximately a same height, the coils may experience a same fluid pressure, e.g., due to the force of gravity, in the coils, and thus tend to have similar cryogen flow rates. This may help the coils to operate in the same, or substantially the same, way with respect to condensate production, particularly if gravity is relied on at least in part to cause the flow of cryogen in the coils. The three outer coils 3, 4 and 5 all spiral downwardly from the uppermost portion (e.g., 19) and connect to the exhaust manifold 24 at the bottom of the coil set 13a. The innermost coil 2, however, is somewhat different. As mentioned above, the innermost coil 2 has inner and outer coil loops. Although the innermost coil 2 spirals downwardly at the inner coil loop 2b (see FIG. 9) from the uppermost portion (e.g., at 19) to near the bottom of the coil set 13a, the coil 2 makes a turn (at reference 2c in FIG. 9) and begins to spiral upwardly at the outer coil loop 2a. Near the top of the coil set 13a, the outer coil loop 2a terminates and the outlet of the coil 2 extends downwardly for connection to the exhaust manifold 24. Though not shown in FIGS. 8 and 9, the exhaust manifold 24 may be connected to the cryogen outlet 18 for removal of cryogen from the condenser 1. FIG. 10 shows a cross sectional view along the line 10-10 in FIG. 9 and provides a close-up view of the inlets of the coils 2, 3, 4, 5 extending from the supply manifold 23 upwardly to the top of the coil set 13a. For further reference, FIG. 11 shows a perspective view of the coil set 13a with the inner coils shaded more lightly and outer coils shaded more darkly.

The coils of the coil sets, the cryogen supply conduits, supply and exhaust manifolds and cryogen outlet may be made of any suitable material, such as a stainless steel tubing or other suitable material, e.g., that can withstand temperature gradients to be experienced using a liquid cryogen in the coils and a potentially significantly warmer gas environment around the coils. Similarly, other components of the condenser 1 may be made of stainless steel or other suitable material, e.g., to withstand the expected temperature variations, potentially corrosive environments (such as for use with a volatile vapor condensate that is highly corrosive to metals or other materials), and other operating conditions. Although the coils in the embodiments described above have a helical shape with generally circularly shaped loops, other arrangements are possible. For example, the coils could have a helical configuration with loops having a square, rectangular, elliptical, triangular or other suitable shape, the coils could have a flat, spiral shape (e.g., where each coil is generally located in a single plane), a serpentine shape, or other suitable configurations. The cryogen may be a liquid material, such as a liquid nitrogen, liquid carbon dioxide, liquid argon, liquid oxygen, liquid helium, liquid air or other suitable material, or may be a higher temperature liquid, gas or mixture of liquid and gas. Flow of cryogen in the coils may be controlled in any suitable way, and using any suitable control parameters. For example, the condenser 1 may include one or more sensors to detect temperature, gas flow rates, condensate production rates, condensable vapor concentration in the inlet gas, cryogen flow rates, cryogen supply and/or outlet temperatures, and/or other parameters at one or more locations. A controller (e.g., including a suitably programmed general purpose computer with suitable software or other operating instructions or other suitable electronic circuitry, one or more memories (including non-transient storage media that may store software and/or other operating instructions), valves, pumps, temperature sensors, pressure sensors, input/output interfaces (such as a visible display, keyboard, mouse or other pointing device, printer, speaker, etc.), communication buses or other links, switches, relays, triacs, or other components necessary to perform desired input/output or other functions) may use the condenser parameter information (which may include user input information) to control one or more aspects of the condenser operation, such as gas inlet flow rate, cryogen flow rate to one or more coils, condensate removal (e.g., operate a scraper to remove ice from one or more coils based on detected conditions), and so on.

Having thus described several aspects of at least one embodiment of this invention, it is to be appreciated various alterations, modifications, and improvements will readily occur to those skilled in the art. Such alterations, modifications, and improvements are intended to be part of this disclosure, and are intended to be within the spirit and scope of the invention. Accordingly, the foregoing description and drawings are by way of example only. It will be apparent that other embodiments and various modifications may be made to the present invention without departing from the scope thereof. The foregoing description of the invention is intended merely to be illustrative and not restrictive thereof. The scope of the present invention is defined by the appended claims and equivalents thereto.

Claims

1. A cryogenic condenser, comprising:

a housing defining an interior space, the housing having a gas inlet for introducing gas with a condensable vapor and a gas outlet for exhausting gas;

first and second coil sets, each coil set including at least one coil located in the interior space, each of the coils having an inlet and an outlet and arranged to conduct a cryogen from the inlet to the outlet, the coils being arranged to cool the condensable vapor in the interior space to condense the vapor into a liquid or solid form; and

a cryogen supply including at least one valve and arranged to independently control flow of cryogen in at least two of the coils.

2. The condenser of claim 1, wherein the housing defines a cylindrical space having a top and a bottom, and first coil set is located above the second coil set.

3. The condenser of claim 1, wherein the housing has a cylindrical shape having a top and a bottom, and the gas inlet is arranged at a side of the cylindrical shape and the gas outlet is arranged at the top of the cylindrical shape.

4. The condenser of claim 3, comprising an inlet baffle arranged at the gas inlet to direct gas toward the bottom of the cylindrical shape.

5. The condenser of claim 4, further comprising at least one baffle at the top or bottom of the cylindrical shape to direct gas flow in the interior space in a vertical direction.

6. The condenser of claim 4, wherein the inlet baffle is positioned between the gas inlet and the coils.

7. The condenser of claim 4, further comprising a bottom baffle at the bottom of the cylindrical shape that inhibits gas flow in a horizontal direction, and at least one top baffle at the top of the cylindrical shape that inhibits gas flow in a horizontal direction.

8. The condenser of claim 1, wherein the coils in the first and second coil sets have a substantially equal length.

9. The condenser of claim 1, wherein each of the coil sets includes at least two coils that have a substantially equal length.

10. The condenser of claim 9, wherein the coils in each coil set have a common inlet conduit and a common outlet conduit.

11. The condenser of claim 9, wherein the coils in each coil set are nested.

12. A cryogenic condenser, comprising:

a housing defining an interior space, the housing having a gas inlet for introducing gas with a condensable vapor and a gas outlet for exhausting gas;

first and second coils, each coil being located in the interior space, having an inlet and an outlet and arranged to conduct a cryogen from the inlet to the outlet, and having a substantially equal length from the inlet to the outlet, the coils being arranged to cool the condensable vapor in the interior space to condense the vapor into a liquid or solid form; and

a cryogen supply arranged to provide cryogen to the inlet of each of the coils.

13. The condenser of claim 12, wherein the first and second coils are part of a first coil set that further includes at least a third coil, the third coil having a length from an inlet to an outlet that is substantially equal to the length of the first and second coils.

14. The condenser of claim 12, wherein the first and second coils are part of a first coil set, the condenser further comprising a second coil set that includes third and fourth coils that have a substantially equal length.

15. A method for removing a condensable vapor from a gas stream, comprising:

providing a gas with a condensable vapor into a condenser housing;

providing a liquid cryogen into first and second coil sets in the condenser housing to cool the condensable vapor in the interior space to condense the vapor into a liquid or solid form in the condenser housing; and

independently controlling a flow of liquid cryogen in the first and second coil sets.

16. The method of claim 15, wherein the step of independently controlling comprises operating at least one valve for a first cryogen supply for the first coil set independently of operation of at least one valve for a second cryogen supply for the second coil set.

17. The method of claim 15, wherein the first and second coil sets each include:

first and second coils, each having an inlet and an outlet and arranged to conduct a cryogen from the inlet to the outlet, the first and second coils being nested with the second coil being at least partially surrounded by the first coil, and the first and second coils each having an uppermost portion that are located at a substantially equal height.

18. The method of claim 17, wherein the first and second coil sets each include at least a third coil that is nested with the first and second coils, the third coil having an uppermost portion that is located at a substantially equal height at the uppermost portions of the first and second coils.

19. The method of claim 15, wherein first coil set is positioned above second coil set.