HK40100641A - System and method for ultraviolet sterilization of fluids - Google Patents

Description

Systems and methods for ultraviolet sterilization of fluids

Technical Field

This disclosure relates to the field of sterilizing water and other fluids using ultraviolet (UV) light irradiation. More specifically, this disclosure relates to systems and methods for UV sterilizing fluids using plate and frame UV reactors that expose the fluids to UV radiation with controlled depth and surface area.

Background Technology

Ultraviolet (UV) radiation has been used for sterilization purposes for some time. A specific high-frequency band of UV radiation known as UVC is particularly effective for sterilization. Multiple studies have shown that when microorganisms such as bacteria, viruses, molds, yeasts, and protozoa are exposed to deep UVC radiation in the spectral wavelength range of 100 nm to 280 nm, this deep UVC radiation is absorbed by DNA, RNA, and proteins. More specifically, some amino acids that make up proteins actually absorb UV light. This can disrupt the cell membrane of the microorganism, leading to its death. DNA absorption of UVC can lead to thymine-thymine dimerization and the death of the organism. If enough strands are inactivated, DNA/RNA replication is interrupted, and the cell cannot replicate.

UV irradiation technology has been used in the food industry for disinfection/sterilization processes for some time due to its advantages. It is generally the preferred treatment method because chemicals are not introduced into the treated liquid substances during irradiation. Furthermore, the irradiation process does not produce any undesirable byproducts.

A key parameter for microbial sterilization is the UV dose, which is the amount of UV radiation to which a microorganism is exposed. The dose depends on the intensity of the UV radiation and the duration of exposure. Numerous biological studies have established widely accepted typical UV dose requirements for the most common target microorganisms in disinfection. For example, a dose of 60 mJ/ ^cm² is required to achieve a 3-log reduction (99.9%) in Bacillus subtilis (ATCC 6633).

To date, conventional UV systems have been inefficient due to insufficient and inconsistent UV exposure. Therefore, there is a need for UV sterilization systems and methods that provide adequate and consistent UV dosing.

Summary of the Invention

In one aspect, this disclosure describes a reactor for sterilizing a fluid flow. The reactor includes: a frame structure having a longitudinal dimension; and a plurality of UV plate reactors removably insertable into the frame structure in the form of a series extending along the longitudinal dimension of the frame structure, each of the plurality of UV plate reactors including at least one channel of a selected diameter into which the fluid flow is delivered and through; and at least one ultraviolet light source having a selected radiant flux, the at least one ultraviolet light source being coupled to one or more of the plurality of channels.

In another aspect, this disclosure describes a method for sterilizing a fluid flow. The method includes conveying the fluid flow through a reactor having a series of modular UV plates arranged longitudinally, each UV plate reactor including a single or multiple channels of a selected diameter; and irradiating the fluid flow with ultraviolet radiation of a selected radiant flux as the fluid flow is conveyed through the multiple channels of the UV plate reactor. The diameter of the multiple channels and the radiant flux of the ultraviolet light source are selected to provide a precise dose of ultraviolet radiation to the fluid flow within the confined space of the multiple channels in order to achieve sterilization of the fluid flow.

In another aspect, the dosage and flow characteristics of the flow can be selected to optimize the sterilization of the fluid flow.

These and other aspects, features, and advantages will be understood from the following description of certain embodiments of the invention, as well as from the accompanying drawings and claims.

Attached Figure Description

Figure 1 is a perspective view of a section of a UV reactor system according to an embodiment of the present disclosure, depicting two plate reactors arranged in series with a unidirectional flow channel.

Figure 2 is a further perspective view of an embodiment of the UV reactor system, showing a total of ten plates assembled in a series with single-channel flow. The fluid passes through each plate sequentially as it is exposed to UV irradiance.

Figure 3 is a side view of an exemplary arrangement for a plate reactor that flows in a single channel or multiple channels.

Figure 4 is a schematic side view showing the product fluid flow passing sequentially through the various plate reactors and being exposed to UV radiation.

Figure 5 is a schematic side view of a UV reactor according to another embodiment of the present disclosure.

Figure 6 is a plan view of an embodiment of a standalone UV plate reactor according to this disclosure, featuring a fishbone design.

Figure 7 is a cross-sectional view of a section of an exemplary plate reactor according to the present disclosure, in which multiple fluid channels are irradiated from multiple sides.

Figure 8 is a cross-sectional view of a section of an alternative embodiment of the plate reactor according to the present disclosure, in which multiple fluid channels are irradiated on one side.

Figure 9 is a cross-sectional view of a section of a further embodiment of a plate reactor in which a single fluid channel is irradiated on multiple sides.

Figure 10 is a cross-sectional view of a section of a further embodiment of a plate reactor in which a single fluid channel is irradiated on a single side.

Detailed Implementation

This disclosure describes a system and method for sterilizing fluids, such as water or liquid food that may or may not contain organic compounds, using ultraviolet (UV) radiation, preferably UVC radiation. The entire UV radiation spectrum covers a wavelength range of 100 nm to 400 nm and is divided into three regions, the shortest of which is UVC in the range of 100 nm to 280 nm, which emits highly efficient sterilization power. The UVC sterilization wavelength at 260 nm is most effective for killing harmful microorganisms in the air, water, and on surfaces.

The system disclosed herein includes an embodiment of a reactor (“UV reactor”) comprising a series of modular plate reactors. In some embodiments, the plate reactor includes a stainless steel shell, a quartz crystal sleeve, a UV radiation source, and at least one channel through which the fluid to be sterilized is conveyed. The steel shell and quartz sleeve separate the UV radiation source from the fluid flow. Within the UV reactor, the fluid flow is guided through the channels of the series of plate reactors. The fluid circulates into and out of the UV reactor via inlet and outlet under the control of a VFD (Variable Frequency Drive) pump. The UV sterilization method does not require the removal of oxygen from the fluid prior to irradiation. Furthermore, the method does not require limitation of the liquid temperature range during sterilization. The disclosed system further improves upon conventional methods by controlling the precise dimensions of the fluid flow to be sterilized and the amount of UV light flux directed onto that fluid flow.

The ultraviolet sterilization method uses specific UV light-emitting diodes (LEDs) to irradiate the liquid, but adaptation with non-LED lamps is also possible. Each plate reactor in the plate reactor is equipped with an array of several LEDs. The amount of UV radiation (preferably UVC radiation) directed onto the fluid depends on the amount of UV luminous flux of the LED array and also on how many plate reactors the fluid is directed through (referred to as "residence time"). The inventors have discovered that directing the fluid flow through generally uniform, small-diameter channels (which may be, for example, about 4 mm) provides sufficient (preferably optimal) dosing for sterilization purposes.

In one embodiment, the disclosed UV reactor is adapted to operate in a continuous mode, i.e., not in an intermittent mode. In this embodiment, the sterilization method is a continuous flow system, which provides a more efficient and effective sterilization process. Some sterilization reactors achieve the desired dosage in a batch mode by irradiating the fluid for a certain exposure time and then stopping the irradiation exposure. In contrast, the UV reactor embodiment disclosed herein provides dosage control in a continuous system that does not require disconnection to achieve the required quantitative dosing. The avoidance of downtime enables higher sterilization throughput. It should be noted that all fluid contact materials used are FDA (Food and Drug Administration) approved.

The plate reactor may comprise a corrugated metal plate having multiple fluid channels or a single channel compressed within a frame. A UV radiation source is positioned on one side of one or more channels within the plate reactor, while the liquid to be sterilized flows on opposite sides of the channels within the plate reactor. A cooling system may be coupled to the UV radiation source. The cooling system may use liquid or air to dissipate heat generated from the UV radiation source. Figure 1 is a perspective sectional view of a section of a UV reactor 100 according to an embodiment of the present disclosure, depicting the inlet end 110 of the shell and two plate reactors 120, 125 arranged in series. The number of plates shown is merely illustrative, and UV reactors typically include more than two plates, but may also include fewer. The plate reactors 120, 125 are arranged in series along a longitudinal axis defining the direction of fluid flow through the UV reactor. In some embodiments, the spacing between the plate reactors may be between 4 mm and 10 mm, but larger or smaller spacings are also possible. Plate reactors 120 and 125 may be corrugated and include multiple channels, or alternatively, the plate reactor may include a single channel through which the fluid to be sterilized flows substantially transversely to the longitudinal axis of the UV reactor.

In the embodiment depicted in Figure 1, there are three inlet ports 112, 114, and 116 at the inlet end of the housing 110. The fluid to be sterilized flows through each port. The fluid to be sterilized is also referred to herein as the “product” flow. Each fluid flow flows unidirectionally downwards (in the transverse direction relative to the longitudinal axis) from the inlet end 110 through the first plate reactor 120, where the fluid is exposed to UV radiation in the exposure area 122 of the first plate reactor 120 and is sterilized. The fluid gushing from the bottom of the plate reactor 120 flows longitudinally for a distance under fluid pressure and then flows upwards through the second plate reactor 125, where the fluid is again exposed to UV radiation in the exposure area 128 of the second plate reactor 125 and is further sterilized. Thus, the fluid entering the reactor through the inlet ports 112, 114, and 116 undergoes considerable radiation exposure along the longitudinal path of the fluid through the UV reactors in a series of plate reactors with UV light sources.

Figure 2 is a perspective sectional view depicting the entire embodiment of the UV reactor shown in the section of Figure 1. The UV reactor 100 shown in Figure 2 comprises ten plate reactors 120, 125, 130, 135, 140, 145, 150, 155, 160, and 165 arranged in series along a longitudinal axis within the shell (not shown in the cutout view). Fluid entering the UV reactor 100 passes sequentially through each plate reactor 120-165 and is exposed to the UV irradiance located within each plate reactor. In the depicted embodiment, each plate reactor 120-170 includes a single channel through which fluid is conveyed and exposed to UV radiation. The total irradiance provided by the plate reactors 120-165 is calibrated and set to the dose required to achieve complete sterilization of the fluid. The fully sterilized fluid that has flowed through the plate reactors 120-170 exits through an outlet port on the outlet end 170 of the UV reactor shell. To achieve the desired production rate of fluid through the reactor, a flow rate between 10 gallons and 1000 gallons per minute is used, depending on the size of the reactor and the desired application.

Each end plate includes an inlet and an outlet connected to external infrastructure for receiving and discharging product fluids used for sterilization. The UV light source generates heat, which affects the lifespan of the light source. Therefore, the UV light source requires cooling during operation. To cool the LEDs and provide sufficient heat transfer, the coolant fluid is also circulated through the UV reactor in a countercurrent manner, opposite to and in some cases to the flow direction of the product stream. Figure 2 also schematically depicts this circulation of the coolant. In the described embodiment, the cold coolant 210 enters the UV reactor at the top of the figure and initially proceeds horizontally, then vertically in a top-to-bottom direction via the corresponding cold fluid inlet orifice of the plate. In other embodiments, the flow may similarly be bottom-to-top. As the cold fluid 210 proceeds through the back of the UV reactor, it cools the UV LEDs. The coolant, to which heat from the UV LEDs has been transferred, exits at the bottom of the back of the reactor. In addition to the corresponding inlets and outlets for the product stream, each plate reactor 120-165 also includes corresponding inlets and outlets for the coolant stream.

A side view of an exemplary arrangement of plate reactors for flow in a single or multiple channels is shown in Figure 3. As in the embodiment shown in Figure 2, ten plate reactors (two of which, 130 and 155, are labeled for illustration) are assembled in a string extending longitudinally on a frame 105. Fluid to be sterilized enters at inlet 112, flows through the plate reactor, and the sterilized fluid exits at outlet 175. The plate reactors are modular and can be easily and safely inserted into or removed from the reactor frame. The size (and surface area) of the plate reactors can also vary widely depending on the application. Exemplary dimensions, for example, range from 5 ft to 11 ft in height/width. As shown in Figure 3, the plates are vertically assembled in a string extending longitudinally between the end plates of the frame.

Figure 4 is a schematic side view illustrating the fluid flow through the UV reactor. As shown, the fluid enters the UV reactor at the top of the figure and initially travels longitudinally through the reactor from right to left via the corresponding inlet orifice 112 of the first plate 110. As the fluid travels through the UV reactor, it is alternately directed downwards and upwards into channels such as 410, 420, and 430. For example, after exiting the first plate reactor 120, the fluid is redirected to flow vertically to the top of the second plate 125, where it exits. From the second plate reactor, the fluid flows downwards. This movement is facilitated by baffles such as 445 and 450, which abut the reactor shell and prevent further longitudinal flow of the fluid, thus vertically redirecting the flow. The baffles may be, as shown, part of an extension of the plate reactor, or may be separate components for redirecting the flow. The fluid exiting the last plate 165 is directed to the fluid outlet 175 and the exterior of the UV reactor.

Figure 5 is a schematic side view of a UV reactor according to this disclosure with an alternative design. In this UV reactor 500, the fluid to be sterilized enters the bottom inlet 512 and travels horizontally along the bottom of the shell 505 to the end of the reactor. When the bottom of the reactor is filled with fluid, the liquid enters a channel between plate reactors (e.g., 520, 530) and two channels 510, 550 located at the longitudinal ends of the reactor between the plate reactors and the shell 505 (a total of eleven channels in the depicted embodiment). In each of these channels, the fluid is unidirectionally conveyed upwards in a vertical path. After exiting the vertical channel, the liquid travels horizontally along the top of the UV reactor to the outlet 560.

In all the above embodiments, the number and size of the channels in the plate reactor are designed to provide the desired radiation exposure and residence time. For example, in some embodiments, it is desired that the channel diameter is about 3-5 mm and the residence time in each plate is in the range of 30 seconds to 1.5 minutes. It should be noted, of course, that these are exemplary parameters and can be adjusted to provide sufficient dosage for the purpose of fluid sterilization.

As previously stated, the radiation source is preferably an LED that emits radiation in the ultraviolet range of the EM spectrum, more preferably in the UVC range, which, as previously stated, is the wavelength range of the electromagnetic spectrum between 100 nm and 280 nm. In some embodiments, the plate reactor is corrugated and includes grooves, slots, or single channels with depths ranging from 4 mm to 11.5 mm. The slots of the plate may contain a number of UV LEDs or a single channel with a number of UV LEDs. For example, each slot may include approximately 100 LEDs, but more or fewer LEDs may be used depending on the desired application.

The spacing between LEDs in the reactor relative to the channel in which the LEDs are located is a crucial parameter for achieving the desired irradiance. The distance-to-height ratio (DHR) is defined as the ratio of the distance between two adjacent LEDs to the height of the channel. The DHR is determined by the channel area to provide the required irradiance for sterilizing the fluid. Light refracted at the surface of the quartz sheath provides an irradiance pattern on the target plane of the fluid, thus allowing for a uniform radiation distribution.

Figure 6 is a plan view of an embodiment of a standalone UV plate reactor according to the present disclosure. The depicted embodiment includes channels arranged in a herringbone design. The plate reactor 600 includes an elastomeric gasket sealing system and UV LED light sources, such as 605, 610, and 615, incorporated on the plate according to an embodiment of the present disclosure. The plate reactor 600 includes inlets and outlets/openings (referred to herein as orifices) leading to external infrastructure for product entry and exit. For example, the plate reactor shown in Figure 6 illustrates a top orifice 620 for product fluid entry. Fluid entering the top orifice 620 flows down through channels to a bottom orifice 625, where it exits. Fluid is guided through channels, such as 630 formed by a herringbone design. Orifices 620 and 625 are preferably aligned with orifices of other plate reactors located within the reactor. The outer edge of the plate reactor may include an elastomeric gasket 640 forming a peripheral seal. The gasket seal prevents fluid flow between the plate reactors from flowing outside the channels intended for fluid flow. Each plate reactor may be equipped with additional seals, such as 650, to also retain fluid within the channels. The material and design of the seals are selected based on the liquid being treated and can be implemented in a variety of ways, including, for example, from elastomeric gaskets to laser welds.

As described above, the UV reactor and ultraviolet sterilization method of this disclosure employ a modular approach that allows for modification of each part of the UV reactor assembly as needed. Plate reactor units can be added or removed for new tasks, and users can easily modify the plate reactor and other components to accommodate expanded capacity requirements. After disassembly, the plate reactor can be cleaned and inspected to the stringent standards required by the food processing, dairy, and pharmaceutical industries. The plate reactor is preferably formed using hygienic materials such as stainless steel. Similarly, suitable hygienic materials are also used to form the sealing material in areas in contact with food. The gap between the UV light source and the fluid path through the plate reactor can also be adjusted to accommodate wider separation to handle relatively viscous fluids or fluids containing particles.

Figure 7 is a cross-sectional view of a section of an exemplary plate reactor 700 in which multiple fluid channels are irradiated from multiple sides. The section of the plate reactor is formed by welding or otherwise joining plate sections such that two orifices 704, 708 are formed between the plates. A first fluid channel 710 flows through the first orifice 704. The fluid channel 710 is confined within a quartz sleeve 715. The quartz sleeve 715 is substantially transparent to UV radiation. A first UV radiation source 722 and a second UV radiation source 724 are positioned on opposite sides of the quartz sleeve 715 within the orifice 710. UV radiation emitted from both UV light sources 722, 724 passes through the quartz sleeve, and thus the fluid within the channel 710 is exposed to radiation emitted from the two light sources 722, 724. Similarly, a second fluid channel 730 flows through the second orifice 708. The fluid channel 730 is confined within a second quartz sleeve 735. The third UV light source 742 and the fourth UV light source 744 are positioned on opposite sides of the quartz sleeve 735 and the UV radiation from the two light sources 742 and 744. The fluid within the second channel 730 is thus exposed to the radiation emitted from the light sources 742 and 744. The UV radiation sources 722, 724, 742, and 744 are protected from contact with the fluid by both the quartz sleeve and a plate (e.g., stainless steel).

Figure 8 is a cross-sectional view of a section of an alternative embodiment of a plate reactor 800 in which multiple fluid channels are irradiated on one side. Similar to the embodiment shown in Figure 2, the section of the plate reactor is formed by plate sections welded or otherwise joined such that two orifices 804, 808 are formed between the plates. However, the orifices 804, 808 in this embodiment are asymmetrical, unlike the orifices shown in Figure 7. A first fluid channel 810 flows through the first orifice 804. The fluid channel 810 is confined between a plate 812 and a quartz sleeve 815. A UV radiation source 820 is positioned on the side of the quartz sleeve 815 opposite to the channel 810, irradiating the fluid flowing within the channel 810. Similarly, a second fluid channel 830 flows through the second orifice 808. The fluid channel 830 is confined between plates 832 within a second quartz sleeve 835. The second UV radiation source 840 is positioned on the side of the quartz sleeve 835 opposite to the channel 830. The second UV radiation source 840 irradiates the fluid flowing within the channel 830.

Figure 9 is a cross-sectional view of a section of a further embodiment of a plate reactor 900 in which a single fluid channel is irradiated on multiple sides. The plate reactor 900 includes a first plate 904 and a second plate 908 positioned parallel to each other. A first set of UV LEDs (e.g., 912, 914) is positioned in the region between the upper plates of the first plate 904, and a second set of LEDs (e.g., 922, 924) is positioned opposite a first set of LEDs on the second plate 908. A quartz sleeve 930 is positioned between the first and second sets of UV LEDs surrounding a fluid channel 940. As fluid flows through the channel 940, the fluid is irradiated by both the first and second sets of UV LEDs. The plate reactor 900 includes a first flange 942 and a gasket 944 at a first end, and a second flange 946 and a gasket 948 at a second end. The flanges and gaskets provide a peripheral seal for controlling fluid flow and fasteners that allow easy installation and removal of the plate reactor within the UV reactor. As in other implementations, in this implementation, the UV radiation source is separated from the liquid flow by a plate (e.g., stainless steel) and a quartz sleeve.

Figure 10 is a cross-sectional view of a section of an embodiment of a plate reactor 1000 in which a single fluid channel is irradiated on a single side. The plate reactor 1000 includes an irradiation plate 1004 and a base plate 1008, on which a set of UV LEDs (e.g., 1012, 1014) are positioned. A space between a sleeve 1020 and the base plate 1008 defines a fluid channel 1030. As fluid flows through the channel 1030, the fluid is irradiated by the set of UV LEDs (e.g., 1012, 1014). The plate reactor 1000 includes a first flange 942 and a gasket 944 at a first end, and a second flange 946 and a gasket 948 at a second end. The flanges and gaskets provide a peripheral seal for controlling fluid flow and fasteners that allow easy installation and removal of the plate reactor within the UV reactor. As in other embodiments, in this embodiment, the UV radiation source is separated from the liquid flow by a plate (e.g., stainless steel) and a quartz sleeve.

The disclosed UVC reactor system offers several advantages over related technologies. The disclosed reactor system provides an enhanced UV irradiation transfer zone plate and a compact design, resulting in a more efficient sterilization process. Compared to conventional UV sterilization systems, it exhibits very little to no shadowing. UV light travels in a straight line, so any shadow or obstruction will reduce its efficiency. The design of this disclosure eliminates shadowing and exposes the entire liquid to irradiation.

Simply by adding more modular panels to the frame structure, the sterilization "lethality" can be significantly improved efficiently and effectively. Traditional systems would require a complete redesign of the plasma discharge lamp and the construction of a new system. Furthermore, the reactor can be easily and inexpensively adapted to sterilize different types of products with varying sterilization specifications. Additionally, the reactor design provides more efficient cooling of the UV light source, which helps extend the light source's photolife.

Furthermore, the ultraviolet sterilization reactor and method disclosed herein do not require the removal of oxygen from the fluid prior to irradiation, nor does the presence of nitrate nitrogen necessitate effective sterilization of the liquid. Additionally, this method does not require limitation on the temperature range of the liquid during sterilization.

It should be understood that any structural and functional details disclosed herein should not be construed as limiting the systems and methods described, but are provided as representative embodiments and/or arrangements to teach those skilled in the art various ways of implementing the methods. It should also be understood that similar parts in the figures represent similar elements in several figures, and not all embodiments or arrangements require reference to all parts and/or steps described and illustrated in the figures.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used herein, unless the context clearly indicates otherwise, the singular forms “a” and “the” are intended to include the plural forms as well. It should also be understood that the terms “comprising” and/or “including”, when used in this patent specification, expressly indicate the presence of stated features, integrals, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and/or groups thereof.

Orientation terms are used herein for convention and reference purposes only and should not be construed as limiting. However, it is generally accepted that these terms may be used by the observer. Therefore, no limitation is implied or inferred.

It should also be understood that the wording and terminology used herein are for descriptive purposes and should not be considered restrictive. The use of “including,” “comprising,” or “having,” “containing,” “involving,” and variations thereof in this document means to cover the items listed thereafter and their equivalents and additional items.

Although the invention has been described with reference to exemplary embodiments, those skilled in the art will understand that various changes can be made without departing from the scope of the invention, and equivalents can be substituted for its elements. Furthermore, those skilled in the art will understand that many modifications can be made to the teachings of the invention to suit particular apparatus, situations, or materials without departing from the basic scope of the invention. Therefore, the invention is not intended to be limited to the specific embodiments disclosed as the best mode considered for carrying out the invention, but rather the invention will include all embodiments falling within the scope of this disclosure as understood by those skilled in the art.

Claims (18)

1. An ultraviolet (UV) reactor for sterilizing a fluid flow, the ultraviolet (UV) reactor comprising: A frame structure having a longitudinal dimension; and A plurality of plate reactors, wherein the plurality of plate reactors are removably inserted into the frame structure in the form of a string extending along the longitudinal dimension of the frame structure, each of the plurality of plate reactors including at least one channel into which the fluid flow is delivered; and At least one ultraviolet light source having a selected radiant flux, the at least one ultraviolet light source being positioned to irradiate the at least one channel. 2. The reactor of claim 1, wherein the diameter of at least one channel and the radiant flux of the ultraviolet light source are selected to provide a selected dose of ultraviolet radiation to the fluid flow in the confined space of the at least one channel in order to achieve sterilization of the fluid flow. 3. The reactor of claim 2, wherein the diameter of the at least one channel is between 3 mm and 10 mm. 4. The reactor of claim 1, wherein the ultraviolet light source comprises a plurality of light-emitting diodes (LEDs) radiating in the UVC spectral range. 5. The reactor of claim 4, wherein each of the plurality of plate reactors comprises a quartz sleeve and a housing, the housing separating the fluid within the plurality of channels from the plurality of LEDs irradiating the fluid. 6. The reactor of claim 1, wherein a coolant is conveyed through the reactor to cool the plurality of LEDs. 7. The reactor of claim 1, wherein the frame reactor and the plate reactor are made of stainless steel. 8. The reactor of claim 1, wherein each of the plurality of plate reactors includes a plurality of channels for conveying the fluid to be sterilized. 9. The reactor of claim 1, wherein each of the plurality of plate reactors includes a sealing system adapted to confine the fluid flow to the at least one channel. 10. The reactor of claim 1, wherein the sealing system comprises an elastomeric gasket. 11. The reactor of claim 1, wherein the sealing system comprises a laser weld. 12. A method for sterilizing a fluid flow, the method comprising: The fluid flow is conveyed through a reactor having a series of modular plate reactors arranged along a longitudinal dimension, each plate reactor including multiple channels of a selected diameter; As the fluid flow is conveyed through the plurality of channels of the plate reactor, the fluid flow is irradiated with ultraviolet radiation of a selected radiant flux; The diameter of the plurality of channels and the radiant flux of the ultraviolet light source are selected to provide a precise dose of ultraviolet radiation to the fluid flow in the confined space of the plurality of channels in order to optimize the sterilization of the fluid flow. 13. The method of claim 12, wherein the irradiation step is performed using a plurality of light-emitting diodes (LEDs) radiating in the UVC spectral range of 110 nm to 280 nm. 14. The method of claim 13, the method further comprising separating the plurality of LEDs from the delivered fluid. 15. The method of claim 14, wherein the plurality of LEDs are separated from the delivered fluid by a housing and a quartz crystal sheath that is transparent to UV radiation. 16. The method of claim 12, the method further comprising circulating a coolant to transfer and dissipate heat from the plate reactor. 17. The method of claim 16, wherein the coolant is circulated in a countercurrent manner along a path different from the flow of the fluid to be sterilized. 18. The method of claim 12, wherein the fluid is continuously input and transported through the reactor.