WO1994002680A1

WO1994002680A1 - Hydrocyclone photo-reactor

Info

Publication number: WO1994002680A1
Application number: PCT/US1993/001974
Authority: WO
Inventors: Bruno S. Marcoccia; J. W. Chamblee
Original assignee: Kamyr, Inc.
Priority date: 1992-07-24
Filing date: 1993-03-04
Publication date: 1994-02-03

Abstract

Non-gas fluid (45), such as a cellulose pulp slurry (e.g. kraft pulp), a liquid containing dissolved solids, etc. is treated with electromagnetic radiation, such as ultraviolet light from a mercury arc lamp, or a laser UV light source. The fluid to be treated (45) is introduced into the first end of a vortex, and the electromagnetic radiation (26) is introduced into the fluid from the central axis of the vortex. A reactive fluid, such as bleaching gas or liquid (21), is typically also introduced into the fluid within the vortex from the exterior of the vortex. The treatment is effected with a large surface area to volume ratio, and with a large surface renewal rate, and with the UV light passing in the opposite direction of the reactant fluid, resulting in highly efficient treatment.

Description

HYDROCYCLONE PHOTO-REACTOR

BACKGROUND AND SUMMARY OF THE INVENTION

The parent applications describe methods and apparatus for chemically and/or physically reacting different types of fluids. For example, according to the parent applications it is possible to react a slurry or liquid with a reactive gas or liquid in such a way as to provide rapid intimate contact, to provide the fastest reaction that is practical. The methods and apparatus of the parent applications can be used to react caustic solutions, sulfur dioxide solutions, and spent alkaline bleach plant liquors with chlorine and chlorine dioxide, or for reacting kraft mill white, green, and black liquors with an oxygen containing gas, or reacting various types of cellulose pulp, including virgin or recycled kraft pulp, TMP, εulfite pulp, and CTMP pulp with ozone, or like treatment gases.

According to the present invention, some of the basic principles from the parent applications are utilized for reactions that are induced by electromagnetic radiation. The invention is particularly applicable to reactions in which ultraviolet light is a catalyst or other important component for reaction of dissolved solids in a liquid, for the bleaching of pulp, or for a wide variety of other uses. The electromagnetic radiation may be supplied by itself, although preferably a reactive fluid, such as a bleaching chemical, is utilized in conjunction with the electromagnetic radiation. Some examples of treatment that can be performed according to the invention are vaεte water purification (for example removing color and chlorinated organic compounds (AOX) from bleach plant effluents utilizing ultraviolet light, and oxygen, ozone, hydrogen peroxide, and/or chlorine dioxide, or deodorizing, disinfecting and neutralizing hazardous pollutants in industrial waste and wastewater streams), photo-oxidative bleaching of kraft pulps,- fiber surface treatment of all grades of cellulose pulp, and de-halogenation of AOX in fully bleached kraft pulps.

According to one aspect of the present invention, a method of effecting electromagnetic radiation induced reaction of a first non-gas fluid is provided. The method comprises the following steps: (a) Introducing the first fluid into a first end of a vortex, having an exterior, and a central interior, the vortex action being minimal at the central interior. (b) Introducing electromagnetic radiation into the first fluid from the central interior of the vortex to cause a perceptible change in the first fluid. And, (c) removing treated first fluid from the second end of the vortex. Also there is preferably the further βtep (d), coincident with step (b), of introducing a reactive fluid into the first fluid in the vortex from the exterior of the vortex, the combination of reactive fluid and electromagnetic radiation causing a perceptible change in the first fluid.

Step (b) is preferably practiced by introducing ultraviolet light radiation into the first fluid, such as from a mercury arc lamp. Where the reactive fluid is a treatment gas, any residual treatment gas may be removed from the first end of the vortex. The method is practiced on liquids, slurries (such as cellulose pulp having a consistency of about 1-8%) or the like, typically, but not necessarily, related to the production of cellulose pulp.

The vortex action allows for the treatment of the fluid both by thin-film radiation and by radial mixing of the irradiated substrates, in addition to providing a "counter-current" treatment of the irradiated substrate (in that chemical reactants and the electromagnetic radiation are introduced throughout the opposite sides of the thin film) . Thus the invention also includes a method comprising the steps of: (a) Establishing a flow path of the first fluid in which the first fluid has a large surface area to volume ratio. (b) Effecting movement of the first fluid in the flow path to provide a large surface renewal rate. And, (c) causing reactant fluid and electromagnetic radiation to pass into the first fluid in the flow path in generally opposite directions.

According to another aspect of the present invention, a fluid treatment device is provided. The fluid treatment device comprises: A main body defining an interior hollow vortex chamber having a first end, a second end, and a central axis. A tangential fluid inlet at the first end of the main body, remote from the central axis, for introducing fluid with a whirling action so that a vortex is established in the vortex chamber. A treated fluid outlet from the second end of the vortex chamber. Means for generating electromagnetic radiation. And, means for mounting the means for generating electromagnetic radiation along the central axis within the vortex chamber.

The main body of the fluid treatment device preferably comprises an interior porous wall defining the vortex chamber, with means for introducing a fluid (e.g. gas) through the interior porous wall. The interior porous wall is typically a surface of revolution, such as a cylinder or a cone. The means for generating electromagnetic radiation preferably comprises a mercury arc lamp having an elongated transparent (e.g. quartz) tube, a high pressure glass bulb containing mercury and mounted within the tube, and a pair of electrodes attached to the bulb. The mercury arc lamp also includes a non-reactive gas (e.g. nitrogen) purge system for the tube. The means for mounting the mercury arc lamp comprises a pedestal having a plurality of hollow legs extending from it, and connected to the second end of the main body. The legs straddle the treated fluid outlet but do not interfere with the passage of treated fluid through it.

It is the primary object of the present invention to provide for the effective reaction of fluids while irradiated with electromagnetic radiation. This and other objects of the invention will become clear from an inspection of the detailed description of the invention, and from the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGURE 1 is ^~ longitudinal view, partly in cross-section and partly in elevation, of an exemplary fluid treatment device according to the present invention;

FIGURE 2 is a longitudinal view, partly in cross-section and partly in elevation, of a mercury arc lamp utilized in the device of• FIGURE 1;

FIGURE 3 is a top plan view of the mercury arc lamp of FIGURE 2; and

FIGURE 4 is a bottom plan view of the mercury arc lamp of FIGURE 2 with mounting structures, the electrical cords and nitrogen purge not being shown.

DETAILED DESCRIPTION _.OF THE DRAWINGS

The most basic apparatus according to the present invention, as illustrated in FIGURE 1, is a form of gas sparged hydrocyclone such as shown in parent application serial no. 07/573,978 filed August 28, 1990. The device 10 comprises a main body 11 defining a hollow interior vortex chamber 12 having a first end 13, a second end 14, and a central axis 15. A tangential fluid inlet 16 is provided at the first end 13, remote from the central axis 15 for introducing non-gas fluid (e.g. a liquid, liquid slurry, or liquid solution) with a whirling action so that a vortex is established in the chamber 12. A treated fluid outlet 17 extends from the second end 14 of the vortex chamber 12.

Also, preferably, the main body 11 includes an exterior wall 18, and a porous interior wall 19, a space 20 being defined between them. Means are provided, such as the inlet 21, for introducing a treatment fluid (typically a treatment gas, but also possibly a treatment liquid) into the space 20, to pass through the porous wall 19 radially inwardly into the vortex chamber 12. The porous wall 19 typically is a surface of revolution, such as a cylinder, cone, or the like. When treatment gas is utilized, an outlet 23 for residual gas is provided at the first end 13 of the body 11, along the central axis 15. An optional, tangential, second outlet 24 adjacent the bottom 14 of the body 11 also may be provided, if desired.

According to the present invention, means 26 for generating electromagnetic radiation are provided within the vortex chamber 12. The means 26 preferably comprises a UV light source laser, or — as illustrated — a mercury arc lamp or a laser operating in the appropriate wavelength (e.g. UV), and means — shown generally by reference numeral 27 in FIGURE 1 — are provided for mounting the means (e.g. lamp) 26 substantially along the central axis 15 within the vortex chamber 12. The means 27 preferably comprises a pedestal 28 having a plurality (e.g. three -- see FIGURES 1 and 4) of legs 29 connected to the bottom 14 of the main housing 11 for supporting the lamp 26. If desired, one or more radially extending arms (one such arm shown in dotted line at 30 in FIGURE 1) may be provided at the top of the electromagnetic radiation generating means 26 for stabilizing it within the vortex chamber 12.

An exemplary mercury arc lamp according to the present invention is illustrated at reference numeral 26 in FIGURES 2 and 3, and the pedestal 28 thereof, with dependent legs 29, is illustrated in FIGURE 4.

The mercury arc lamp 26 preferably comprises an elongated transparent tube 32 (e.g. a quartz well), with a high pressure glass bulb 33 mounted within it. The bulb 33 contains mercury, shown schematically at 34 in FIGURE 2, only a small amount of mercury being necessary. Electrodes 35, 36 are connected to the bulb 33 to supply an arc which excites the mercury and generates ultraviolet light. Electrical cords 37, 38 lead from the electrodes 35, 36 to a source of electric power (see 39 in FIGURE 1).

Also, it is desirable to cool the lamp 26, particularly the bulb 33, for a proper and long life operation. This is preferably accomplished utilizing a gas purge system, including a non-reactive gas such as nitrogen. For example, in the pedestal bottom 28 of the lamp 26, a hollow nipple 40 may be provided connected by conduit 41 to a source of nitrogen gas (42 in FIGURE 1). Although not shown in FIGURE 2, the legs 29 extending from the pedestal 28 (see FIGURES 1 and 4) preferably are hollow, and the electrical wires 37, 38 in the purge gas conduit 41 may extend through them. For example three hollow legs 29 — as seen in FIGURE 4 — may be provided, equally spaced around the periphery of the pedestal 28, and each containing either a wire 37, 38 or the purge gas conduit 41.

Utilizing the apparatus 10 heretofore described, a method of effecting electromagnetic radiation induced reaction of a first, non-gas fluid is provided. The non-gas fluid may be a liquid or a slurry, typical (but by no means exclusive) liquids being waste water liquids, such as liquids containing color and/or AOX, such as bleach plant effluents from cellulose pulp producing facilities; or cellulose pulps, of all different grades, and both virgin and recycled fibers, including kraft pulps, and typically having a solids consistency of about 1-8%, and even including fully bleached pulps.

The first fluid -- as shown by arrow 45 in FIGURE 1 -- is tangentially introduced into the vortex chamber 12 through the tangential inlet 16, establishing a vortex -- shown schematically by line 46 in FIGURE 1 — within the chamber 12. Electromagnetic radiation -- such as ultraviolet light from the mercury arc lamp 26 — is introduced into the whirling fluid in the vortex 46, passing radially outwardly from the interior of the vortex 46 (that is from the central axis 15). The treated fluid is removed — as indicated by arrow 47 in FIGURE 1 — from the outlet 17 of the second end of the body 11.

Preferably, such as in waste water purification, or photo-oxidative bleaching of pulp, a reactant chemical is also introduced into the fluid within the vortex 46. This is accomplished by supplying the treatment fluid through inlet 21 into space 20, passing through the porous wall 19 radially inwardly into contact with the fluid in the vortex 46, from the exterior of the vortex. Typical reactant fluids include ozone, oxygen, and/or chlorine dioxide; and oxygen, ozone, chlorine dioxide, hydrogen peroxide or chlorine. The first set of chemicals is typically used for removal of color and AOX from bleach plant effluents using ultraviolet radiation, while the second set of chemicals is used for the photo-oxidative bleaching of kraft pulps. A wide variety of reacting chemicals, or in some cases no reacting chemical at all, may also be used for the fiber surface treatment of all grades of cellulose pulp, or for the de-halogenation of chlorinated organic compounds and fully bleached pulps, such as kraft pulps.

The vortex action, with introduction of electromagnetic radiation from the central axis and a reactant chemical from the exterior of the vortex, results in extremely effective treatment, combining thin film irradiation (that is with large surface area to volume ratios) with the radial mixing of irradiated substrates (that is large surface renewal rates), while the radiation passes "counter-current" to the reactant chemical in the thin film. Thus, utilizing the method and apparatus heretofore described, a flow path of the fluid is established in which the fluid has a large surface area to volume ratio (vortex 46); the fluid is moved in the flow path to provide a large surface renewal rate (inherently occurring, due to radial mixing, in the vortex 46); and reactant fluid (treatment gas through inlet 21) and electromagnetic radiation (e.g. ultraviolet light from mercury arc lamp 26) pass into the fluid in the flow path (vortex 46) in generally opposite directions, achieving optimum treatment of the fluid.

It will thus be seen that according to the present invention a method and apparatus has been provided which are highly beneficial for a wide variety of procedures for treating fluids with electromagnetic radiation. While the invention has been herein shown and described in what is presently conceived to be the most practical and preferred embodiment thereof, it will be apparent to those of ordinary skill in the art that many modifications may be made thereof within the scope of the invention, which scope is to be accorded the broadeεt interpretation of the appended claims so as to encompasε all equivalent structures and procedures.

Claims

WHAT IS CLAIMED IS:

1. A method of effecting electromagnetic radiation induced reaction of a first non-gas fluid, comprising the steps of:

(a) introducing the first fluid into a first end of a vortex, having an exterior, and a central interior, the vortex action being minimal at the central interior;

(b) introducing electromagnetic radiation into the first fluid from the central interior of the vortex to cause a perceptible change in the first fluid; and

(c) removing treated first fluid from the second end of the vortex.

2. A method as recited in claim 1 comprising the further step (d), coincident with step (b), of introducing a reactive fluid into the first fluid in the vortex from the exterior of the vortex, the combination of reactive fluid and electromagnetic radiation causing a perceptible change in the first fluid.

3. A method aε recited in claim 2 wherein εtep (b) is practiced by introducing ultraviolet light radiation into the first fluid.

4. A method as recited in claim 3 wherein εtep (a) is practiced by introducing kraft pulp into the vortex, and εtep (d) is practiced by introducing a bleaching chemical into the vortex.

5. A method aε recited in claim 3 wherein εtep (a) iε practiced by introducing a liquid containing disεolved εolids including one or both color and AOX, and wherein εtep (d) iε practiced by introducing a fluid capable of removing one or both color and AOX from the liquid.

6. A method aε recited in claim 5 wherein step (d) is practiced by introducing a fluid selected from the group consiεting esεentially of oxygen, ozone, hydrogen peroxide, chlorine dioxide, and mixtures of two or more of oxygen, ozone, hydrogen peroxide, and chlorine dioxide.

7. A method aε recited in claim 1 wherein step (a) is practiced by introducing bleached kraft pulp into the vortex, and wherein εtep (b) iε practiced to effect de-halogenation of chlorinated organic compounds in the bleached kraft pulp.

8. A method as recited in claim 2 wherein step (a) is practiced by introducing cellulose pulp into the vortex, and steps (b) and (d) are practiced to effect surface treatment of the pulp.

9. A method aε recited in claim 1 wherein step

(a) is practiced by introducing cellulose pulp having a consistency of about 1-8%.

10. A method aε recited in claim 3 wherein εtep

(b) is practiced by generating the UV light with a mercury arc lamp, or a laser.

11. A method aε recited in claim 2 wherein εtep (d) iε practiced utilizing a treatment gaε, and compriεing the further εtep (e) of removing any residual treatment gaε from the first end of the vortex.

12. A fluid treatment device, compriεing: a main body defining an interior hollow vortex chamber having a firεt end, a second end, and a central axis; a tangential fluid inlet at the first end of the main body, remote from the central axis, for introducing fluid with a whirling action εo that a vortex iε established in εaid vortex chamber; a treated fluid outlet from the second end of εaid vortex charnber; meanε for generating electromagnetic- radiation; and meanε for r.ounting said means for generating electromagnetic radiation along said central axis within εaid vorτex chamber.

13. A device aε recited in claim 12 wherein εaid main body compriεeε an interior porouε wall defining εaid vertex chamber; and further comprising meanε for introducing a fluid through εaid interior porouε wall.

14. A device as recited in claim 13 wherein εaid interior pcrouε wall ip a εurface of revolution.

15. A device aε recited in claim 14 wherein εaid meanε for generating electromagnetic radiation comprises a mercury arc lamp, or a UV light source laser.

16. A device aε recited in claim 14 further compriεing an outlet at εaid firεt end of εaid main body along said central axis.

17. A device aε recited in claim 12 wherein εaid meanε for generating electromagnetic radiation compriεeε a mercury arc lamp, or a UV light εource laεer.

18. A device aε recited in claim 17 wherein εaid generating meanε iε a mercury arc lamp, compriεing an elongated tranεparent tube, a high preεεure glaεs bulb containing mercury and mounted within εaid tube, and a pair of electrodeε attached to the bulb.

19. A device aε recited in claim 18 wherein εaid mercury arc lamp further compriεeε a non-reactive gaε purge εyεtem for εaid tube.

20. A device aε recited in claim 18 wherein εaid means for mounting εaid mercury arc lamp compriεeε a pedeεtal having a plurality of hollow legε extending therefrom and connected to εaid second end of εaid main body, εaid legε εtraddling said treated fluid outlet but not interfering with paεεage of treated fluid therethrough.

21. A method of treating a firεt non-gaε fluid from a proceεε for the production of cellulose pulp with a reactant fluid and electromagnetic radiation, compriεing the εteps of:

(a) establishing a flow path of the first fluid in which the first fluid has a large εurface area to volume ratio;

(b) effecting movement of the firεt fluid in the flow path to provide a large surface renewal rate; and

(c) cauεing reactant fluid and electromagnetic radiation to paεε into the firεt fluid in the flow path in generally oppoεite directionε.

22 . A method aε recited in claim 21 wherein εtep (c) iε practiced by cauεing ultraviolet light to paεε into the firεt fluid.

23. A method aε recited in claim 22 wherein εtepε (a) and (b) are practiced utilizing celluloεe pulp aε the firεt fluid.

24. A method aε recited in claim 23 wherein εtep (c) is further practiced utilizing a bleaching chemical aε the reactant fluid.

25. A method as recited in claim 24 wherein εtepε (a) and (b) are practiced utilizing kraft pulp having a conεiεtency of about 1-8%.