WO2010056456A2

WO2010056456A2 - Vacuum degassifier-photochamber

Info

Publication number: WO2010056456A2
Application number: PCT/US2009/060795
Authority: WO
Inventors: Jens Wiik Jensen; Eric Dickman
Original assignee: Uni-Control, Llc
Priority date: 2008-11-12
Filing date: 2009-10-15
Publication date: 2010-05-20
Also published as: WO2010056456A3

Abstract

Herein disclosed is a degassed photochamber system. The system comprises a pressure vessel, disposed above a reactor generating a gas product, in fluid communication with the reactor, having a gas volume above the reactant surface of the reactor; a gas removal means, in fluid communication with the gas volume contained in the pressure vessel; and a radiation source, disposed above the pressure vessel and reactor, having at least one emitter for exposing a portion of the reactant surface of the reactor.

Description

VACUUM DEGASSIFIER-PHOTOCHAMBER

BACKGROUND

Field of the Invention

[0001] This invention relates generally to microbial fermentation, and more specifically, to the activation and product recovery of during a microorganism mediated fermentation process. Background of the Invention

[0002] Certain biological reactions also produce gaseous products suitable for recover and harvesting. For example, a number of processes have been known for the production of methane gas by fermentation. In this process, the continuous fermentation operation is configured for obtaining 300 1 of a fermentation gas per kg of the organics having a methane concentration of 70% by volume. In this instance, the temperature conditions of thermophilic range (60° C.) where the high fermentation efficiency is achieved are adopted. The quantity of methane gas generated is 6.3 m ³ /day and the retention times required for the gasification and liquefaction are, respectively, 6 and 2 days. The methane gas formation process in the gasification tank is the rate-limiting step of the whole fermentation process. [0003] Alternatively, hydrogen may be produced in a fermentation reaction. Biological production of hydrogen using photosynthetic, fermentative, and/or heterotrophic microorganisms have been described. Certain photosynthetic bacteria have been demonstrated to oxidize carbon monoxide to hydrogen by the water-gas shift reaction:

CO + H₂O → CO₂ + H₂ (1)

In particular, the Rubrivivax, Rhodospirillum, Rhodopseudomonas, and other genus's have been described as including such a pathway. Further, carbon monoxide exposure induces the de novo expression and synthesis of a hydrogenase capable of converting the CO component of syngas into gaseous hydrogen (H₂).

[0004] As the microorganisms preferentially inhabit aqueous environments, the solubility of product gases represents a harvesting limiting step in fermentation process to produce a gaseous product. The mass transfer of a gaseous material from the aqueous environment without toxicity complications represents a challenge to industrial implementation of a bio-mediated gaseous product methods.

[0005] Furthermore, microorganisms capable of fermentation reactions typically require the supplemental energy, or environmental signals for activation. In particular, the light or radiation absorption, in a certain wavelength activates, up-regulates, or generally enhances the production of commercially important gaseous products. Natural sunlight activation is inefficient in continuous operations, and may not adequately serve to activate reaction at the correct timing to maximize production. As the microorganisms preferentially inhabit aqueous environments, light penetration into the media is another critical factor, and represents a reaction activation-limiting step.

[0006] Particularly, the recent implementation of deep shaft reactors for fermentation reactions has demonstrated a need in the industry for a reactor-head design for synthesis gas harvesting coupled with a radiation emitter for activation.

BRIEF SUMMARY

[0007] Herein disclosed is a degassed photochamber system. The system comprises a pressure vessel, disposed above a reactor generating a gas product, in fluid communication with the reactor, having a gas volume above the reactant surface of the reactor; a gas removal means, in fluid communication with the gas volume contained in the pressure vessel; and a radiation source, disposed above the pressure vessel and reactor, having at least one emitter for exposing a portion of the reactant surface of the reactor. In some embodiments, the pressure vessel further comprises a reactor head. In some embodiments, the pressure vessel comprises a gas volume that is in a gas volume to reactor volume ratio of at most 1 :5. In an embodiment, the pressure vessel is configured to have a width that is larger than the reactor width. [0008] In some embodiments, the reactor comprises a deep shaft reactor. In some embodiments, the reactor comprises a fermentation reactor. In some embodiments, the gas removal means comprises a vacuum device. In some embodiments, the gas removal means further comprises at least one outlet means fluidly coupled to pressure vessel, configured for degassing pressure vessel. In some embodiments, the gas removal means further comprises at least one separation means, configured for separating product gas from waste gas. In some embodiments, the separation means comprises a recycle stream, configured for recycling waste gas to reactor for further processing. In some embodiments, the separation means comprises a waste outlet in fluid communication with gas removal means. In an embodiment, the separation means comprises a waste outlet configured for removing waste gases from gas removal means.

[0009] In some embodiments, the emitter comprises a visible light emitter. In some cases, the emitter comprises a UV emitter. In some cases, the emitter comprises an IR emitter. In some embodiments, the radiation source comprises a plurality of emitters. In an embodiment, the plurality of emitters is differentially activated. In an embodiment, the plurality of emitters is discontinuously activated.

[0010] In an embodiment, the radiation source is hermetically sealed within the pressure vessel. In an embodiment, the radiation source is hermetically sealed from the gas volume. In an embodiment, the radiation source comprises at least one optical channel, configured for transmitting light below the reactant surface of the reactor.

[0011] Thus, embodiments described herein comprise a combination of features and advantages intended to address various shortcomings associated with certain prior devices. The various characteristics described above, as well as other features, will be readily apparent to those skilled in the art upon reading the following detailed description of the preferred embodiments, and by referring to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] For a detailed description of the preferred embodiments of the invention, reference will now be made to the accompanying drawings in which:

[0013] FIGURE 1 illustrates a vertical cross-section of an embodiment of a degassed photochamber.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Referring to Figure 1, degassed head 10 comprises headspace 12, vent system 14, and radiation system 16. Degassed head 10 is configured for placement about, or above a reactor 20 configured for fermentation to produce a gas. Degassed head 10 is disposed at least level with or above ground level 1. In certain instances, degassed head 10 may be partially below ground level 1. Degassed head 10 is further configured as a pressure vessel. In certain instances, degassed head 10 is configured to withstand high internal vacuum pressures; alternatively, degassed head 10 is configured to withstand high external vacuum pressures. [0015] Headspace 12 is configured to capture gases released from the fermentation reaction. Headspace 12 is disposed above reactant surface 18. Vent system 14 is configured to de-gas headspace 12. Radiation system 16 is configured to provide radiation to reactor 20, specifically emitted toward reactant surface 18. Reactor 20 comprises a vertical reactor in certain embodiments, although many alternative configurations for may be understood by one skilled in the art. In certain instances, reactor 20 comprises a shaft reactor or a deep shaft reactor. Further, reactor 20 comprises a reactant circulation 22. [0016] Total reactor volume may be calculated by the equation π Li (Wi/2)². Where Li is the depth of the reactor from the top 20a to the bottom in the case of a shaft reactor, and Wi is the width of the reactor. Wi may be the diameter of the reactor in cylindrical instances. Volume of the head may be calculated π L₂ (Wi/2)². The reactor liquid volume may be calculated π L₃ (Wi/2)². In certain embodiments, the volume of the head comprises about 1% to about 50% of total reactor volume, preferably from about 1% to about 10%. In further embodiments, the ratio of the volume of the head to the reactor liquid volume is at least about 1 :2, preferably about 1:5, and more preferably at least about 1:10. In preferred embodiments, the width W₂ of the degassed head 10, is at least greater than the width of the reactor Wi. [0017] In embodiments, vent system 14 is configured to remove gases from reactor 20 and degassed head 10 via headspace 12. Vent system 14 comprises a gas conduit 15 to remove gases from headspace 12. Further, vent system 14 comprises any means known to one skilled in the art for removing, and/or isolating product gases. In certain instances, vent system 14 comprises a system for applying a vacuum to headspace 12. Examples of suitable systems include, but are not limited to blowers, venturi vacuum generation and mechanical vacuum systems, chemical vacuum systems, or combinations thereof as known to one skilled in the art. Chemical vacuum systems may include preferential absorption of a gas component, for example hydrogen, by a membrane. Alternatively, at least a partial vacuum may be applied by ion getter pump or the like configured for trapping atomic products. In certain instances, an ion getter pump would be suitable for capturing hydrogen, oxygen, nitrogen or other diatomic gases remaining in the headspace 12. Vent system 14 comprises product gas-storage unit for batch processing. Alternatively, vent system 14 is continuously processed to remove product gases.

[0018] In certain instances, the waste gases from the fermentation reaction comprise a toxic compound or mixture to the suspension. The waste gases are disposed from vent system 14 by waste removal stream 24. Waste removal stream 24 may comprise combustible gases and be sent to a high temperature incinerator or other combustion facility. Alternatively, waste removal stream 24 may be combusted on-site to provide electrical power. [0019] In further embodiments, vent system 14 comprises gas recycle stream 26. In certain instances, gas recycle stream 26 is removed from waste removal stream 24. Gas recycle stream 26 is in fluid communication with reactor 20. Gas recycle stream 26 may be coupled to reactor 20 by a plurality of conduits. Alternatively, gas recycle stream 26 is fed directly into reactor 20 in order to provide gas lift, decrease density, or otherwise influence circulation 22 as understood by one skilled in the art. In certain embodiments, recycle stream 26 may comprise compounds capable of being combusted, and exhaust gases may be introduced to reactor 20. [0020] Degassed head 10 comprises radiation system 16, disposed at or above the reactor top 20a. Radiation system 16 is disposed above or in headspace 12. In certain instances, radiation system 16 is hermetically sealed from headspace 12 to improve durability. Keeping radiation system 16 hermetically sealed from headspace 12 reduces exposure to corrosive gases, high humidity, and fluctuating temperatures. In embodiments, radiation system 16 is configured to provide radiation to reactor volume surface 22 through out degassed head 10. Radiation system 16 may be configured to provide radiation to a portion of reactor volume surface 22. Radiation system 16 may further comprise a plurality of radiation components 30. Radiation components 30 may be bulbs, tubes, electrodes, light emitting diodes, or other electromagnetic emission sources. In certain instances, radiation components 30 are bulbs.

[0021] Radiation components 30 emit a pre-determined wavelength of light that preferentially penetrates below reactance surface 18. Alternatively, radiation components 30 emit radiation at a predetermined energy, amplitude, or frequency of radiation. In embodiments, the wavelengths penetrate at least to a depth L₄. Depth L₄ maximally is equal to L3. Depth L₄ is pre-determined to affect the largest quantity of microorganisms in reactor 20, and participating in circulation 22.

[0022] In further alternative embodiments, it can be envisioned that radiation components 30 are coupled to an optic channel 32. Optic channel 32 comprises a light path for directing light into reactor 20. In embodiments, optic channel 32 may penetrate into reactor 20 from any direction, or component. In certain embodiments, optic channel 32 is a component of reactor 20, or degassed head 10. Optic channel 32 may be run through vessel, vessel walls, or alternately positioned adjacent to the walls, or other internal structures, without limitation. Alternatively, optic channel 32 may be incorporated into the structure of reactor 20, degassed head 10, or other apparatus, component, or structure in reactor 20. Optic channel 32 is configured to direct light into reactor 20 in regions that light does not typically reach, for example near reactor bottom 20b. Further, optic channel 32 is a coherent light guide. [0023] In certain embodiments, optic channel 32 comprises lenses, prisms, and mirrors configured to direct light into reactor 20. Optic channel 32 may include plastics. Alternatively, optic channel 32 comprises a dielectric material for directing light into reactor 20. Suitable dielectric materials include, but are not limited to fiber optics. [0024] In preferred embodiments, coated, jacketed, or clad fiber optics are implemented to maximize the penetration of light into reactor 20. In preferred embodiments, the optic channel conducts at least about 2.5% (250 foot candles) of the light of the sun (-10,000 foot candles). Alternatively, the optic channel is configured to provide at least about 1,400 foot candles to the reactor 20. Optic channel may be further modified exteriorly such that reactants and/or microorganisms are prevented from attaching, forming biofϊlms, plaques, or otherwise altering or fouling the light conduction of the optic channel 32. As understood by one skilled in the art, such modifications would be beneficial for maximizing light energy conduction into reactor 20. [0025] Radiation system 16 is configured to provide radiation for activation of microorganisms. Specifically, radiation system 16 may be targeted to specific wavelengths of light understood by one skilled in the art to activate a CO oxidation pathway. Alternatively, radiation system 16 may be configured to provide radiation for sterilization of reactor 20. In sterilization embodiments, radiation system 16 may comprise ultra-violet (UV) lights configured to eliminate microorganisms. Additionally, radiation system 16 may comprise infrared (IR) emitters, or heaters, in order to raise the temperature of headspace 12, reactor volume surface 22, or reactor 20.

[0026] Degassed head 10, including vent system 14 and radiation system 16, is a de-gassed photochamber. In embodiments, the de-gassed photochamber has a vacuum applied to remove gas released into the headspace 12 for capturing and isolating gas for additional purposes. In the case of the present disclosure, degassed head 10 captures gas from fermentation reactions for fuels, fuel cells, and other purposes as known to one skilled in the art. In certain instances, vent system 14 acts to remove certain gas particles, for example oxygen radicals, which may deflect, absorb, impede, or otherwise inhibit emitted radiation from radiation system 16 from impinging on reactant surface 18.

[0027] Application of a vacuum to headspace 12 via vent system 14 is configured to control gas production in reactor 20. In certain instances, the partial pressure of product gas in headspace 12 dictates the production rates throughout the reactor system 10. In certain instances, headspace 12 may be controlled to maintain a high product gas partial pressure in order to control toxic compounds in reactor 20. High product gas partial pressure may slow further fermentation reactions.

[0028] Additionally, degassed head 10 may be configured to control overall fermentation to rate by controlling radiation system 16. Radiation system 16 is activated, flashed, or otherwise operated intermittently, serving to activate only a portion of the microorganisms, for example those located at or near reactant surface 22, at a given time. In one embodiment, the radiation system 16 may serve to operate radiation components in portions of the degassed head differentially. For instance, radiation components 30 in certain zones, areas, or other spacial patterns may be activated in time and reaction dependent means. Alternatively, the radiation system 16 is activated at time, cycle, or gas product concentration determined periods. Radiation system 16 is configured for selective operation to maximize product gas production. [0029] While the preferred embodiments of the invention have been shown and described, modifications thereof can be made by one skilled in the art without departing from the spirit and teachings of the invention. The embodiments described and the examples provided herein are exemplary only, and are not intended to be limiting. Many variations and modifications of the invention disclosed herein are possible and are within the scope of the invention. Accordingly, the scope of protection is not limited by the description set out above, but is only limited by the claims which follow, that scope including all equivalents of the subject matter of the claims.

Claims

CLAIMSWe Claim:

1. A degassed photochamber system comprising: a pressure vessel, disposed above a reactor generating a gas product; in fluid communication with the reactor; having a gas volume above the reactant surface of the reactor;

a gas removal means, in fluid communication with the gas volume contained in the pressure vessel; and a radiation source, disposed above the pressure vessel and reactor; having at least one emitter for exposing a portion of the reactant surface of the reactor.

2. The system of claim 1 wherein the pressure vessel further comprises a reactor head.

3. The system of claim 1 wherein the pressure vessel comprises a gas volume that is in a gas volume to reactor volume ratio of at most 1 :5.

4. The system of claim 1 wherein the pressure vessel is configured to have a width that is larger than the reactor width.

5. The system of claim 1 wherein the reactor comprises a deep shaft reactor.

6. The system of claim 1 wherein the reactor comprises a fermentation reactor.

7. The system of claim 1 wherein the gas removal means comprises a vacuum device.

8. The system of claim 1 wherein the gas removal means further comprises at least one outlet means fluidly coupled to pressure vessel, configured for degassing pressure vessel.

9. The system of claim 1 wherein the gas removal means further comprises at least one separation means, configured for separating product gas from waste gas.

10. The system of claim 9, wherein the separation means comprises a recycle stream, configured for recycling waste gas to reactor for further processing.

11. The system of claim 9 wherein the separation means comprises a waste outlet in fluid communication with gas removal means.

12. The system of claim 9 wherein the separation means comprises a waste outlet configured for removing waste gases from gas removal means.

13. The system of claim 1 wherein the emitter comprises a visible light emitter.

14. The system of claim 1 wherein the emitter comprises a UV emitter.

15. The system of claim 1 wherein the emitter comprises an IR emitter.

16. The system of claim 1 wherein the radiation source comprises a plurality of emitters.

17. The system of claim 16 wherein the plurality of emitters is differentially activated.

18. The system of claim 16 wherein the plurality of emitters is discontinuously activate.

19. The system of claim 1 wherein the radiation source is hermetically sealed within the pressure vessel.

20 The system of claim 19 wherein the radiation source is hermetically sealed from the gas volume.

21. The system of claim 1 wherein the radiation source comprises at least one optical channel, configured for transmitting light below the reactant surface of the reactor.