Patent ID: 12247194

DETAILED DESCRIPTION

FIG.2illustrates an exemplary system200in which air210is processed using a nitrogen separator220employing a nitrogen separation technology to produce a gaseous stream of nitrogen230and a residual gaseous stream240substantially of oxygen. At least some of the separated nitrogen is directed into a nitrogen fixation reactor250(referred to herein also as a Haber reactor) which also receives a stream of hydrogen260, while the residual oxygen rich stream240is optionally directed into a bioreactor270, depending on whether the microbes being cultivated require, or benefit from, the presence of oxygen. At least some of the ‘fixed’ nitrogen from the nitrogen separator220, in the form of ammonia, ammonium, or other soluble form of nitrogen is directed into the bioreactor270. As used herein, “Haber reactor250” refers to the overall system ofFIG.1from condenser to cooling chamber unless context indicates otherwise.

It will be appreciated that while the ammonia pathway280shows ammonia flowing directly from the Haber reactor250to the bioreactor270, the pathway280represents both the direct flow from the Haber reactor250to the bioreactor270as well as indirect flow through further processing steps to generate other suitable nitrogen containing compounds from the ammonia. As used herein, “fluid communication” encompasses both direct flow between the end points as well as indirect flow that includes passing through one or more of valves, regulators, condensers, reservoirs, and chemical processing steps. Thus, the bioreactor270can be in fluid communication with the Haber reactor250through one or more chemical processing steps that convert the ammonia from the Haber reactor250into another fixed nitrogen compound derived from the ammonia stream. In this context, ammonia will be understood to be an example of a fixed nitrogen compound derived from the ammonia stream.

Any ammonia produced in the Haber reactor250but not immediately directed into the bioreactor270can be stored for later use (seeFIG.5) or directed to another use. It will be understood that in various embodiments the residual oxygen-rich stream240can be further fractionated to remove one or more residual gases and in this way create an oxygen rich stream with or without carbon dioxide, with or without carbon monoxide, with or without argon, and so forth, so better suit particular microbes. If the residual oxygen rich stream240contains some CO2or residual N2, these might also be absorbed, or fixed by the autotrophic microbes, or, in other cases passed through the bioreactor270.

In some embodiments, the ammonia that has been produced can be stored and later disassociated back to molecular hydrogen and molecular nitrogen. This reaction may be performed in a number of ways including spontaneously, via heating, via use of catalysts, or other methods. A method of separating the disassociated gases includes membrane based separation, selective adsorption using an adsorbent such as a zeolite, which in some cases may have a metal organic framework, or another selective adsorbent, selective reactivity, or other method to separate the nitrogen and hydrogen. Since the reverse of thirone Haber process, 2NH3to N2+3H2, is endothermic, it can be used as a source of cooling or heat removal. In some embodiments this transition may be carried out in such a way as to provide cooling to a process by transferring heat to the reaction and thus cooling the process either directly, or indirectly via a heat exchanger. In further embodiments the ammonia is disassociated, and optionally used for cooling as described, but the resulting gases are not separated, instead the mixed gases are directed into the bioreactor270.

The bioreactor270, in these embodiments, comprises a vessel filled with a liquid medium in which a population of microbes is dispersed which are capable of using ammonia as a source of nitrogen. The liquid medium in the bioreactor270comprises a variety of chemical nutrients which supply the nutritional requirements of the microbes. These include but are not limited to phosphate, carbonate, chloride, iron, magnesium, manganese, cobalt, calcium, tungsten, selenium, bromine, sodium, nickel, protons, hydroxide, ammonia, ammonium, nitrate, nitrite, zinc, potassium, iodine, copper, and oxygen, in various forms, most of which are as charged ions.

The bioreactor vessel270comprises, in various embodiments, at least one sparger through which gases are added to the bioreactor270. The bioreactor vessel270also comprises at least one liquid input port via which liquids can be added, at least one port through which gases can be vented, and at least one port through which the liquid medium can be withdrawn. The various ports of the bioreactor270may be controlled by valves which can be configured to allow the passage of material, block the passage of material or vary the amount of material which passes into or out of the bioreactor.

The Haber reactor250receives molecular nitrogen (N2) from the nitrogen separator220, and receives molecular hydrogen (H2)260from a hydrogen source (not shown). Exemplary sources for feedstock hydrogen are described below. The nitrogen separator220, in various embodiments, can employ fractional distillation, pressure swing adsorption, or any other suitable method, or combination of methods or steps, to concentrate nitrogen from the air.

As noted above, the Haber reactor250optionally comprises a catalyst and also comprises a heater to raise the temperature of the reactor250to a temperature higher than the external ambient temperature, and the reactor250can operate at a pressure greater than the ambient atmospheric pressure. In the exemplary Haber reactor shown inFIG.1, employing an iron catalyst with a suitable promoter like K2O, CaO, SiO2, and Al2O3, or another catalyst, the gases are brought to a pressure of 200 atm and a temperature of 450° C. Inside the Haber reactor the N2and H2react to form ammonia (NH3). A cooling chamber cools the resulting gases to the point where the ammonia will condense into a liquid. The liquid ammonia is then removed from the cooling chamber via a port and then conveyed either directly, or indirectly via a holding vessel (not shown), to the bioreactor270. The movement of liquid ammonia into the bioreactor270may be assisted by a pump or other pressure source such as the elevated pressure inside the Haber reactor. Ammonia from the Haber reactor may also be further reacted to form other nitrogen-containing compounds, such as urea, and conveyed either directly, or indirectly via a holding vessel, to the bioreactor270. Since in this invention it is not paramount to react hydrogen as completely as possible, a lower efficiency catalyst is preferable. Examples of such include an iron catalyst with a suitable promoter like K2O, CaO, SiO2, and Al2O3, and/or catalysts comprising Cr, Ru, Mn, Pt, and Pd. A suitable catalyst can additionally, or in the alternative comprise a biocatalyst such as one or more enzymes like a nitrogenase, and/or an organism which comprises at least one nitrogenase enzyme such as bacteria including cyanobacteria such asTrichodesmium, Nostocand Cyanothece, green sulfur bacteria, Azotobacteraceae,rhizobiaandFrankia, Clostridia, and Archea and others. Any catalyst which affects the reaction of H2and N2to form NH3potentially can be used. Also, no added catalyst may be used in some embodiments, as the reaction of H2and N2to form NH3can proceed without a catalyst.

The catalyst may be dispersed within the reactor as a coating, powder, or particle, or disposed within other particles such as a zeolite or other molecular sieve, and the catalyst can be incorporated into, or provided as, a porous structure, or impregnated on a membrane, or packed in a bed of a fluidized bed, or dispersed in a solution, or incorporated into biomass or any other type of support or structure. Moreover, the lower efficiency catalyst may be also comprised of a higher efficiency catalyst, but at a lower purity than used in high-efficiency ammonia production. Suitable catalysts can also comprise a mix of catalysts of varying efficiency. The advantage of some lower efficiency catalysts can be their lower costs.

In addition to, or in place of, the catalyst the reactor may comprise a molecular sieve or other material meant to increase the residency time of the respective gases in the reactor or their exposure to the catalyst or catalytic conditions from NH3formation.

It is noted that a Haber reactor250can be run differently when being used to manufacture ammonia to supply nitrogen to a bioreactor process because the bioreactor270does not have to be run continuously, or for maximum throughput, or in the case of supporting the culture of hydrogen oxidizing bacteria, for maximizing utilization of hydrogen. The factors of pressure, temperature and residence time thus can be different than those favored for the bulk industrial production of ammonia. It is possible that these parameters can be tuned to yield an overall higher efficiency for production of ammonia for support of a bioreactor than those which are used for industrial ammonia production. The reactor may comprise any catalyst as described above with respect to the catalyst for the Haber reactor250.

One modification to the normal operation of the Haber reactor250is to change the ratio of nitrogen to hydrogen provided into the Haber reactor250. Normally in the Haber process the molar ratio of N2to H2is 1 to 3, in line with the stoichiometry of the reaction. In some embodiments of the present invention, the ratio of N2to H2may be between 1:3.1 and 1:10, or between 1:10 and 1:100, or between 1:100 and 1:1000, or between 1:1000 and 1:10000, or between 1:10,000 and 1:1,000,000.

Decreasing the amount of nitrogen relative to the amount of hydrogen entering the reactor250favors a more complete reaction of the nitrogen fraction into ammonia and thus reduces the amount of unreacted nitrogen in the unreacted stream while it increases the amount of unreacted hydrogen therein, making the unreacted stream more suitable for introduction into the bioreactor270as a source of hydrogen (seeFIG.3). Though the presence of nitrogen gas is not normally deleterious to the bioreactor270, and in certain cases may provide a benefit, the nitrogen gas in some cases will pass through the bioreactor270and can also accumulate in the headspace of the bioreactor270. The presence of unreacted nitrogen in the headspace of the bioreactor270, or in pass through gas, will increase as headspace gases are recycled and this effect may necessitate occasionally purging the nitrogen gas from the headspace.

Controlling the ratio of nitrogen to hydrogen supplied to the Haber reactor250can be an element of the control system described herein, and this ratio may be changed depending on the degree of present or projected need for a nitrogen compound, such as NH3, or hydrogen in the bioreactor270. Normally, the ratio of hydrogen to nitrogen supplied to a Haber reactor is 3:1 on a volume to volume basis, and this results in an output from the Haber reactor250of an unreacted gas stream comprising both unreacted hydrogen and unreacted nitrogen. By increasing the ratio of hydrogen to nitrogen to above 3 to 1, the amount of unreacted nitrogen leaving the Haber reactor250in the unreacted stream will decrease. In normal operation of a Haber reactor250, about 15% of the hydrogen and nitrogen react in each pass through, so even in the case of a system operated under conditions different than those used to manufacture ammonia commercially, it may be desirable to recirculate the gases multiple times. However, by having an excess of hydrogen above the normal 3 to 1 ratio of hydrogen to nitrogen it can be guaranteed that the final pass through gas will be very rich in hydrogen and have very little nitrogen. In various embodiments the ratio of nitrogen (N2) to hydrogen (H2) is maintained for at least part of the time at a ratio between 1:4 and 1:10, or between 1:10 and 1:100, or between 1:100 and 1:1000, or between 1:1000 and 1:10000, or between 1:10,000 and 1:1,000,000.

In some embodiments of the invention the pressure in the Haber reactor250will be above ambient pressure. Increasing pressure is a well-known and commonly practiced method of favoring the rate of nitrogen fixation in a Haber reactor. In general, commercial Haber reactors are large in size because they are used as a method for producing large amounts of NH3and other fixed nitrogen products. These systems are often operated at 15 MPa, (2200 psi). In some instances the reaction conditions are much higher, 25 MPA (about 3700 psi), or more, however, constructing large systems with such high pressure capabilities is very expensive. In some embodiments of this invention the smaller size of this Haber reactor250will allow operation at higher pressure while maintaining good economics. In some embodiments, the Haber reactor250is maintained at a pressure between 75 TO 65 MPA, (11,000 to 9500 PSI), 65 to 55 MPA, (9500 to 8000 psi), 55 to 45 MPA (8000 to 6500 psi), 45 to 35 MPA (6500 to 5000 psi), 35 to 25 MPA (5000 to 3600 psi), 25 to 15 MPA, (3600 to 2000 psi), 15 to 5 MPA, (2000-800 psi), or 5 to 0.2 MPA (800-30 psi). In some embodiments pressure increases or decreases are used to increase or decrease the rate of reaction. These increases or decreases can be facilitated by high pressure introduction of gases, compression of gases in the reactor, or other means. The reaction of the formation of NH3from hydrogen and nitrogen is exothermic, and this release of energy may be used to increase the pressure of the reaction gas mixture via increased heat or other means.

Normally the Haber reactor250, will be operated to react most of the nitrogen, often over 98% of the nitrogen. In this system there will be an excess of hydrogen and thus the nitrogen will react almost completely and the final pass though gas from the Haber reactor250will have less than 5% residual nitrogen but still contain additional hydrogen. The increased hydrogen in the mix will shift the reaction equilibrium towards ammonia formation and this can allow the Haber reactor250to be operated at lower temperature or pressure. Lower temperature or pressure will greatly slow the Haber reaction to form NH3but will also allow for increased efficiency. In some embodiments the temperature of the reaction will be maintained between 500° C. and 400° C., 400° C. and 300° C., 300° C. and 200° C., 200° C. and 100° C., 100° C. and 30° C., 30° C. and 25° C., or 25° C. and 0° C. In some embodiments the residency time in the Haber reactor250will be increased relative to the residency time in a commercial system. It should also be noted that residual nitrogen in the gas exiting the Haber reactor250which is later introduced into the bioreactor270will not have a deleterious effect on the bioreactor process as the microbes are tolerant of nitrogen and in some cases capable of biological nitrogen fixation.

Because the reaction of H2and N2to produce ammonia is exothermic, the temperature in the Haber reactor250can be increased by retaining the heat produced by the reaction in the reactor250. By operating the reactor250in a cyclical manner where the H2and N2are introduced and then allowed to react exothermically to produce heat in the reactor250, it is possible to modulate the fraction of the gases which react. By operating the reactor250in a cycle where H2and N2are first introduced into the reactor250and the ports of the reactor250are at least partially closed, then the gases are allowed to react exothermically to produce heat in the reactor250whereupon a desired fraction of the gases react, then the output port of the reactor250is at least partially opened. The remaining unreacted gases are either conveyed to the bioreactor270, recycled or vented, and the NH3formed is removed from the reactor250and utilized as described above. Likewise, the above cyclical operation can be configured to allow an increase in pressure which is at least in part due to the increase in heat of the system and its effect on the gases, including the input gases and the ammonia which is formed. The pressure formed in the reactor250can be used in the cycle to vent the gases from the reactor250and to expel the ammonia.

In some embodiments a tube furnace type arrangement can be employed where a tubular reactor shaped like a pipe is configured to receive a stream comprising nitrogen gas, and where the tubular reactor is configured to receive a stream comprising hydrogen gas, and where the tubular reactor is thermally insulated (seeFIG.11). At least some of the H2and N2are reacted within the tubular reactor to product NH3. In some embodiments the tubular reactor may comprise a catalyst. In some embodiments the tubular reactor may be followed by a cooling chamber, which may be a section of pipe, or a vessel, where the temperature of the products is allowed to decrease, or where the temperature is reduced via removal of heat via chilling or other heat reduction, and where the heat may be reduced via reduction of pressure of the gases. Liquid ammonia condenses in the cooling chamber and may be then released, in some embodiments, via the opening of a valve, and may then be collected and used, such as by introduction into the bioreactor, stored for later use in the bioreactor, or diverted for other uses. The pass-through gases may be vented, recycled back into the tubular reactor or introduced into the bioreactor.

In some embodiments a steam methane reformer (SMR) may be used to produce the hydrogen260for the process. SMR is a well understood and widely practiced technique and a dominant technology for industrial hydrogen production. In SMR, methane reacts with steam under 3-25 bar pressure (1 bar=14.5 psi) in the presence of a catalyst to produce hydrogen, carbon monoxide, and a relatively small amount of carbon dioxide. The steam reforming reaction is endothermic, i.e. heat must be supplied to the process for the reaction to proceed.

In a “water-gas shift reaction” carbon monoxide and steam are reacted using a catalyst to produce carbon dioxide and hydrogen. The water-gas shift reaction can be applied to the products of the steam methane reformation reaction to yield still more hydrogen and to convert the carbon monoxide to carbon dioxide. In a final process step the products of the water-gas shift reaction are provided to a separator (analogous to the nitrogen separator220) to remove the carbon dioxide, and any other impurities, from the gas stream, leaving essentially pure hydrogen. The chemical reactions for steam methane reformation and the water-gas shift reaction are shown below:
Steam Methane Reforming Reaction CH4+H2O(+heat)→CO+3H2
Water-Gas Shift Reaction CO+H2O→CO2+H2(+small amount of heat)

The CO2removed from the hydrogen stream in the water-gas shift reaction can at least partially be used as a source of CO2for carbon fixing microbes in the bioreactor270by being conveyed into the bioreactor270. Because the final separation of CO2from the hydrogen stream has a cost associated with it, in cases where the microbes in the bioreactor270require both hydrogen and CO2, it is possible to divert a stream of mixed hydrogen and CO2to the bioreactor270to supply both CO2and hydrogen before the CO2removal step has been completed. Pressure swing adsorption (PSA) is commonly used to remove CO2or other non-hydrogen gases from syngas mixtures. The method works by introducing, for instance, a mixture of H2and CO2into an adsorption system that preferentially traps the CO2in a porous material such as a zeolite, which may have a metal organic framework element, or by another means, thus allowing a hydrogen enriched stream to pass through. The adsorbed CO2is then released to produce a second stream predominantly of CO2, however, this second gas stream still may retain some hydrogen and can thus be used similarly to the gas streams mentioned above.

The system300ofFIG.3is similar to that described inFIG.2but also provides hydrogen to the bioreactor270for the cultivation of hydrogen-oxidizing microbes. In methods of the invention in which hydrogen-oxidizing microbes are cultivated, the microbes consume hydrogen for at least some of their sustenance. In some embodiments, that hydrogen comes from the unreacted stream310.

In further embodiments, hydrogen introduced into the bioreactor270can also comprise hydrogen which did not pass through the Haber reactor250. Such hydrogen can come from a common source that also feeds the Haber reactor250, but provides a stream of hydrogen to the bioreactor270that bypasses the Haber reactor250, or the hydrogen can come from an independent second source. In practice, when growing hydrogen-oxidizing microbes, the hydrogen input to the bioreactor270is sometimes mixed with carbon dioxide and oxygen, however for the sake of clarity this description omits steps of mixing or introducing other gases, and the analogous structures that facilitate the monitoring and control of the mixing and use. Systems where these further gases are mixed are intended to be included in this invention. Likewise this invention also includes systems where hydrogen is added as an aid to the fermentation of heterotrophic substrates, or, where hydrogen is first reacted, often with CO2, to produce formate, acetate, methanol or another energy rich molecule which are then fermented in a system which also requires a source of fixed nitrogen.

It should also be noted that hydrogen is sometimes added to reaction mixtures used for other types of gas fermentation such as carbon monoxide oxidizing bacteria and methane oxidizing bacteria. Since all of these chemoautotrophic fermentation methods require nitrogen which can be added in the form of ammonia, the integration of a Haber reactor250with any of these chemoautotrophic fermentation systems to supply necessary nitrogen is also within the scope of this invention.

System400ofFIG.4is similar to that described with reference toFIG.3. System400further includes at least one nitrogen sensor410disposed within the bioreactor270, or exterior to the bioreactor270and in fluid communication with the interior of the bioreactor270, and a computer-based control system420configured to take sensor readings from the nitrogen sensor410and use this data to control the operation of the various system elements. The nitrogen sensor410, in various embodiments, can be any sensor or sensor system which can detect nitrogen or nitrogen containing compounds including chemical reaction based sensor systems, Raman spectrometers, gas chromatographs, electrochemical probes or any other method or system for measuring nitrogen or its various species including NH3, urea, NO3, etc. In this illustration the computer-based control system420comprises a computing system such as a PC or server, or programmable logic controller, having a processor and running an executable program in order to control various elements of the system, including regulating the flow of hydrogen260to the Haber reactor250and to the bioreactor270, in order to achieve a desired condition such as maximum hydrogen utilization efficiency, maximum microbe growth efficiency, minimum environmental impact, or any other metric or set of metrics.

The computer-based control system420also comprises memory, such as random access memory (RAM), to store information including the executable program, received data, and a log of commands sent to systems, like the nitrogen separator, and controllers such as gas flow regulators. Some or all of the computer-based control system420can be implemented in firmware or hardware. The computer-based control system420includes interfaces with which to take in manual instructions, external data, and sensor readings, and to output control signals and to display an operational status to operators. Computer-based control systems420of the invention are described in greater detail with respect toFIG.4.

The system ofFIG.4further comprises a gas control unit430, such as a gas manifold, in fluid communication with a hydrogen source440and both of the Haber reactor250and the bioreactor270. The gas control unit440receives control signals from the computer-based control system420to regulate the amount of hydrogen delivered to the bioreactor270and to the Haber reactor250. The computer-based control system420can also be in electrical communication with the Haber reactor250and the nitrogen separator220in order to regulate either or both. For example, a detected drop in the concentration of nitrogen in the bioreactor270below a threshold can be corrected by the control system420by increasing the supplies of nitrogen and hydrogen into the Haber reactor250and/or by changing the operating conditions of the Haber process by varying temperature and/or pressure, gas flow rate, gas composition, actuating of valves which control the entrance or egress of gases or liquids in the reactor, and or residence time.

In some embodiments, the nitrogen sensor410measures, either continuously or periodically, the concentration of nitrogen in the bioreactor270. The nitrogen sensor410is configured to sense one or more nitrogen compounds, including ammonia, urea, nitrates or any other form of nitrogen. Nitrogen sensors410can be placed within the liquid medium, in the gas headspace above the medium, within input ports and output ports, within liquid and gaseous effluent streams, and so forth.

System500ofFIG.5is similar to system400ofFIG.4. System500further includes an ammonia reservoir510and an ammonia controller520in fluid communication between the Haber reactor250and the bioreactor270. The reservoir510receives ammonia from the Haber reactor250and the controller520regulates the flow of ammonia from the reservoir510into the bioreactor270under the control of the computer-based control system420.

The system500ofFIG.5also includes at least one hydrogen sensor530disposed within the bioreactor. The computer-based control system420, in these embodiments, also receives sensor readings from the hydrogen sensor530and employs both the hydrogen and nitrogen readings to determine how to regulate hydrogen production, hydrogen flows to the Haber reactor250and bioreactor270, the operating conditions in the Haber process in the Haber reactor250, and the flow of ammonia into the bioreactor270from the reservoir510.

Because the demand for nitrogen in the bioreactor270is related to the population of microbes in the bioreactor270, their growth rate and other factors, the demand for nitrogen varies over time. Therefore, the amount of nitrogen that will need to be supplied will also vary over time. Because there is a delay in time between when the demand for nitrogen exceeds the available nitrogen in the bioreactor270and the ramp-up time of the Haber reactor250(i.e., the time to change the conditions in the Haber reactor250to those favorable for ammonia production, plus the time to actually produce sufficient ammonia and supply it to the bioreactor270), it is highly beneficial to the system500to have this reservoir510of ammonia available for ready delivery, and to recharge the reservoir510when most economical to do so.

The system600ofFIG.6is similar to that described with reference toFIG.5. System600further includes at least one oxygen sensor610disposed within the bioreactor270and in electrical communication with the computer-based control system420. The system600further still includes an oxygen controller620in fluid communication between a source of oxygen, here an electrolyzer630, and the bioreactor270and under the control of the computer-based control system420to regulate the flow of oxygen into the bioreactor270. It will be appreciated that the electrolyzer630here serves as an example of a suitable water splitting method to yield oxygen and hydrogen, but other suitable water splitter systems can be used. These include thermally driven systems, plasma systems, nuclear, chemical or catalytic systems, including those employing biological or enzymatic catalysts, and selectively permeable membranes. Further, another potential oxygen source is the residual gas resulting from separating nitrogen from the air. Oxygen from the electrolyzer630and from the nitrogen separation process can optionally be combined in a reservoir before being introduced into the bioreactor270. The two instances of a nitrogen separator inFIG.6is done for clarity, and is not meant to imply that two such separators are required.

System600also comprises an exemplary source of hydrogen, here again, the electrolyzer630. The electrolyzer630optionally receives electricity from one or more sources. In various embodiments an electricity source can be part of the system600, such as when solar electricity generation is employed. The solar generation can be thermal or photovoltaic, for example. Similarly, other renewable sources such as wind turbines can be part of the system to provide electricity to the electrolyzer630, as well as to other electricity consuming processes within the system600. On-site generation can also come from non-renewable sources in addition to, or in the alternative, such as from diesel generators.

In some embodiments, the electricity for the electrolyzer630is instead purchased from an electricity provider such as the public utility grid. In further embodiments, electricity purchased from an electricity provider supplements electricity generated by the system600when either the system600cannot produce enough electricity to meet its own needs or the cost of electricity is priced below the cost to produce electricity on site.

In some embodiments the NH3may be stored in a reservoir and if a condition arises where hydrogen is in limited supply, or, the cost of producing hydrogen is high, the NH3may be reacted to produce N2and H2, where the H2can then be fed into the bioreactor270and the N2released, or the mixed H2and N2supplied to the bioreactor as a mixed gas, as discussed above. This reaction is endothermic so it can be used to provide cooling functions, such as to cool the bioreactor270.

In other embodiments, in place of electrolyzer630, concentrated solar may be used to drive a thermally driven splitting of water, which may also employ a catalyst. In this case the system600may take in or be supplied external data such as weather forecasts, season of year or other information to determine the availability of sufficient solar energy and this information, as well as information about competing demands, to determine how much hydrogen and ammonia to produce and store to satisfy current and forecasted needs as well as needs for other processes.

FIG.6also illustrates that in some embodiments hydrogen can be supplied by a pipeline from a hydrogen producer, and/or the system600can comprise a steam methane reformer (SMR) to supply hydrogen from a natural gas feedstock. In these embodiments, the computer-based control system420also receives sensor readings from the oxygen sensor610and employs all of the oxygen, hydrogen, and nitrogen readings to determine how to regulate hydrogen production, hydrogen flows to the Haber reactor250and bioreactor270, the Haber process in the Haber reactor250, and the flow of ammonia into the bioreactor from the reservoir510. It is noted that systems of the present invention can include more than one source of hydrogen, and can optionally switch between them according to favorable economics.

It will be appreciated that “SMR” in the drawing ofFIG.6serves to represent a chemical processing system having the ability to perform a steam methane reformation reaction, the ability to perform a water-gas shift reaction on the products of the steam methane reformation reaction, and the ability to separate the products of the water-gas shift reaction into a hydrogen stream and a CO2stream. Only the hydrogen stream is represented inFIG.6flowing to the hydrogen controller, the CO2stream has been omitted for clarity. Although not shown inFIG.6, additional carbon monoxide can be produced by a gasifier capable of receiving a carbon-containing substrate such as municipal solid waste, plastic waste, coal, petroleum, natural gas, hydrocarbons, biomass, textile waste, food waste, sewage, medical waste, chemical waste, byproducts, or any other carbon rich feedstock suitable as a gasification substrate to produce a gas stream including carbon monoxide. The CO gas stream can be reacted with water by the water-gas shift reaction to also produce a stream of hydrogen and CO2. Alternately, the CO gas stream from the gasifier can be added to the output of the steam methane reformation reaction and the combined streams then subjected to the water-gas shift reaction.

FIG.7illustrates an exemplary control system700of the present invention that extends the embodiment ofFIG.6to include a source of CO2, a CO2controller in fluid communication between the source and the bioreactor, and at least one CO2sensor disposed within the bioreactor and in electrical communication with the computer-based control system420, where the computer-based control system420includes instructions that can be executed by the processor to regulate a flow of CO2into the bioreactor based on readings from the CO2sensor, alone or in combination with readings from other sensors in the bioreactor. In various embodiments the source of CO2can be a CO2stream from an SMR as described with respect toFIG.6, or can be from another source, like a commercially delivered CO2tank.

The system700ofFIG.7extends that ofFIG.6to also include one or more growth sensors disposed within the bioreactor and configured to monitor the rate of growth and/or the concentration of microbes in the medium, for instance an optical density sensor which measures cell density in the medium. The system700ofFIG.7further extends that ofFIG.6to include reservoirs for any or all of ammonia, oxygen, hydrogen, CO2, and additional liquid medium.

As shown inFIG.7, the computer-based control system420can be configured to control any or all of a hydrogen generation system, an air separation system for supplying nitrogen, a Haber reactor, a CO2source, and a bioreactor. The computer-based control system420can be further configured to control any or all of an oxygen controller, a hydrogen controller, an ammonia controller, and a CO2controller to regulate flows of these into the bioreactor. The various controls can be based on information received by the computer-based control system420from any or all of the sensors disposed in the bioreactor, sensors that measure the amount stored in any of the reservoirs (such as float sensors for stored liquids and pressure sensors for stored gases), and external data. External data can comprise any or all of weather forecast data, electricity demand projections, and current and projected prices for commodity consumables such as electricity and hydrogen.

FIG.8is a schematic representation of an exemplary system800of the present invention, the bioreactor omitted for clarity, including a number of processes that can further employ ammonia produced by the nitrogen fixation method.FIG.8shows the production of urea from ammonia and CO2.FIG.8also shows the production of nitric acid by the Ostwald process, using ammonia and oxygen, such as from electrolysis.FIG.8further shows the further production of ammonium nitrate from the nitric acid and further ammonia.FIG.8shows further still the production of sulfuric acid from a source of sulfur and oxygen, such as from electrolysis, according to the Contact process and the further manufacture of ammonium sulphate from the further reaction of sulfuric acid with ammonia. Lastly,FIG.8illustrates the production of phosphoric acid from mined phosphorous deposits, and the further reaction of phosphoric acid with calcium and fluorine to create fluorapatite.

The process of making cement and quicklime, as well other mineral processing activities produces a great deal of CO2and requires a great deal of energy. These processes produce CO2from both the combustion of fuels to provide needed heat and as a part of the chemical process of product creation.FIG.9shows an exemplary system900applied to the production of cement, quicklime or other process wherein a mineral substrate, such as calcium carbonate, or limestone containing CaCO3is heated in a kiln process to produce CaO mineral product and CO2gas. In this example concentrated solar is used to produce the heat in the kiln. The concentrated solar heat may also be used to supply heat to a thermal catalytic reactor capable of splitting of water into oxygen and hydrogen streams, and may also be used to provide heat to the Haber reactor. At least some of the hydrogen from the water splitting system is directed into the bioreactor, and at least some of the hydrogen is for some period of time directed into the Haber reactor. At least some of the CO2produced by the reaction of CaCO3to form cement CaO, is directed into the bioreactor. At least some of the NH3produced by the Haber reactor is directed into the bioreactor. Oxygen from the oxygen rich stream byproduct of the nitrogen separator upstream of the Haber reactor, and oxygen produced by the water splitting system, may each be to some extent directed into the bioreactor. Excess oxygen may be stored as compressed gas or liquid and if in excess may constitute an additional product. The control system can be configured to manage in real time and/or based on predictions using sensors, historical and outside data, the various flows and functions, storage, sources etc., of the end to end system900to optimize cost, carbon footprint, product formation or other desired metrics or outcomes. InFIG.9, for simplicity the sensors, controllers, and reservoirs are omitted, but as shown above every gas, liquid or material in the system900can have one, two or all three of a sensor, a controller, and a reservoir.

FIG.10shows a similar system toFIG.9however system1000employs a renewable energy source to produce electricity. The produced electricity is used to power a water splitting system, in this example an electrolyzer. Electricity produced by system1000may also be used to at least partially power the kiln or other processes of the mineral production, and also may at least partially power the Haber reactor or nitrogen separator. In other respects the system1000is similar to the system900ofFIG.9in terms of sensing, control and reservoirs.

FIG.11provides a cross-sectional view of an exemplary tubular furnace reactor1100. The reactor1100comprises at least one input port1110for H2and N2gas, a tubular section1120wrapped with insulation1130to retain at least part of the heat generated by the exothermic formation of NH3from N2and H2. The reactor1100further comprises an exit port1140from which gases are released from the tubular reactor1100, and a condensation chamber1150that condenses the NH3fraction as a liquid which is removed through port1160. In some embodiments the condensation chamber1150may be a tube. In some embodiments, in place of the condensation chamber1150, the reactor1100can include a separator which separates the H2and N2gas streams from the NH3via a membrane, fractional distillation, adsorption, or another method.

FIG.12shows a reactor1200that adds a catalyst1210to reactor1100. The catalyst1210is represented inFIG.12generically, but in various embodiments the catalyst1210may comprise any catalyst as described above with respect to the catalyst for the Haber reactor250.

FIG.13shows a reactor1300that adds controllable valves1310,1320to the reactor1200at the entrance and exit to the tubular section1120. It will be appreciated that other embodiments do not include the catalyst1210while retaining the valves1310,1320. In various embodiments the valves1310,1320are controlled independently, while in other embodiments the valves1310,1320are controlled together.

In some embodiments, the tubular reactor1300can be operated in a cyclical manner where mixed H2and N2gases are introduced into the reactor1300via the inlet port1110. After a period of time, the exit valve1140is at least partially closed, or fully closed, and also the inlet valve1110is at least partially closed or fully closed. Heat is produced by the reaction to produce NH3and that heat is substantially retained within the tubular section1120by the insulation1130. In some embodiments this leads to an increase in the pressure inside the tubular section1120. In some embodiments this leads to an increase in the temperature and pressure inside the tubular section1120. The exit valve1140is opened after a reaction period to allow the mix of unreacted gases and NH3flow into the condensation chamber1150. In some embodiments, cooling the gases in the condensation chamber1150allows the NH3to liquefy while the unreacted gases, predominantly H2, remain gaseous. In some embodiments at least part of this cooling is achieved via the endothermic process of gas expansion by modulating the exit valve1140to control the corresponding flow of the gases into the condensation chamber1150.

FIG.14shows a reactor1400that adds a second exit valve1410to the reactor1300. In reactor1400the second exit valve1410creates a region between the exit valve1140and second exit valve1410. In some embodiments, gasses are released from the tubular section1120through the exit valve1140into the condensation chamber1150at a pressure and a temperature that are both higher than the ambient. Optionally, the temperature in the condensation chamber1150may be higher than ambient, but lower than the temperature within the tubular section1120. The higher than ambient pressure zone within the condensation chamber1150can aid in the condensation of NH3by increasing the temperature at which ammonia condenses. In some embodiments any gases not condensed in the condensation chamber1150are conveyed into the bioreactor270, or recycled back into the tubular section1120, vented to atmosphere, combusted, or stored.

Various embodiments of the present invention also comprise a predictive system to allow production to take place when most economical. Thus, a predictive model as part of the computer-based control system can be used herein, for instance, to prepare the air separation system to begin nitrogen production when utility rates are low, or to wait and bypass the cheaper electricity for a day in which sunshine and steady winds are predicted, and to fill the nitrogen and oxygen reservoirs at that time, unless the model predicts that the reservoirs will be drawn down before that predicted day, in which case electricity from the grid could be used sooner. The predictive model can employ machine learning and/or artificial intelligence and be trained over time to better predict bioreactor demands and to match those demands with feedstocks produced most efficiently.

Predicting bioreactor demands can comprise, for example, training the predictive model based on measurements from sensors in the bioreactor that measure the rate of growth and the concentration of microbes in the bioreactor medium over time. A predictive model trained on accumulated microbial population and growth data correlated with nitrogen demand at the bioreactor can allow the overall system to be run with increased efficiency, as well as help ensure that growth rates and concentrations are not impeded by a lack of available nitrogen. Parameters that can be used to train the predictive model include the strain of microbe(s) being cultivated, media composition, temperature, pH, time of day, day of week, price of hydrogen at a given time, price of both grid and renewable electricity, stage of growth of the microbes and a stated or predictive end of the fermentation, external data which can correlate to sensor data such as weather, season, amount of sunlight, cost and availability or competing demands for ammonia, hydrogen, or any other ingredients used by the system.

Accordingly, a predictive model can be used to configure an electrolyzer or other water splitting technology to produce hydrogen at a rate or in an amount needed, or which is predicted to be needed, in order to supply the Haber reactor with adequate hydrogen to support predicted ammonia needs, as well as to supply the bioreactor with adequate hydrogen to support microbial growth. The computer-based control system can be configured to optimize for a number of parameters including the efficiency of resource utilization, maximum product formation, minimum carbon footprint or a balance of these or other target outcomes.

With regard to the source of hydrogen, there are a number of different ways it can be supplied with variable or fixed costs as well as different carbon footprints, and the like. For example, hydrogen can be provided from a source where the price and availability are set by contract. Hydrogen can also be provided via a number of methods including splitting of water via splitting of water in thermally driven, nuclear and electrolytic processes, by steam methane reformers, water shift reactors or other hydrogen production systems where the cost and availability of hydrogen vary. There are many examples of systems such as these, and by using reservoirs for ammonia produced by the Haber reactor, and for other constituents, the net cost of operating the system can be reduced by refilling the reservoirs when the inputs to the system are cheapest.

A further example is when an electrolyzer is used to produce hydrogen. Here, there is a benefit to producing ammonia when the electricity to run the electrolyzer is cheapest. In many locations electricity is less expensive when used in time periods when overall electricity usage is lower. This is referred to as ‘off peak’ electricity and thus the system can intelligently use off-peak time periods for hydrogen generation to produce ammonia more cheaply and store this in the reservoir for later use. In a similar way, if electrolytic hydrogen is employed where the electrolyzers are at least partially supplied with electricity from solar or wind power, the system can produce ammonia when there are favorable levels of solar or wind available and thus reduce cost by using less purchased electrical power.

Factors of cost are not the only consideration for how the system operates. Reducing CO2emissions for a reduced carbon footprint are also goals or performance metrics in which improvements may be sought. As a still further example, hydrogen can be supplied via water splitting, or via steam reformation of methane where some of the methane is produced from biological processes (ie: biogas or green methane), and the rest is a petrochemical. The predictive model can be trained to take into account the current and predicted ammonia requirements of the bioreactor, the CO2emissions and carbon footprint of each hydrogen source, the overall supply of hydrogen possible from each source, the cost of electricity, the cost of the several methane sources, and derive a dynamic control program which produces the optimal amount of ammonia to satisfy overall goals of lower CO2emissions and lowest cost.

In some embodiments, in which more than one source of hydrogen is available, the computer-based control system can make decisions about how much from each hydrogen source to use at any given time and dynamically regulate them or switch between them. In embodiments in which the electrolyzer can be powered by more than one electricity source, for example, by each of solar power, wind power, and the grid, the computer-based control system can decide which source to employ. Decisions on hydrogen and electricity usage can be based on availability and costs information derived from external sources. In this way reservoirs can be filled, for instance, when conditions are favorable for inexpensive production.

In some embodiments reducing carbon emissions, or atmospheric carbon may be an important goal. In a specific embodiment with this goal, renewable electricity produced by wind, solar or another low carbon method can be used to power an electrolyzer which provides at least part of the hydrogen for the system. In this type of embodiment, the computer control system may also determine the amount of renewable electricity which is supplied to the electrolyzer system to supply the current and anticipated hydrogen needed for the Haber reactor and the bioreactor. This determination can also take into account the amount of electricity demand due to competing uses of electricity and which use of electricity is best. Hydrogen in excess of what is immediately needed may be stored and used in the future or run through a fuel cell to produce electrical power. The decisions about the best uses of hydrogen, electricity, oxygen, water or other resources used or consumed in the process may be determined by using a hierarchy of rules, at least some of which may be derived by the AI system, and others which may be user input to the system as a part of a rule set. The computer-based control system can balance data from many sources, including sensor input, cost of resources, value of resources if sold elsewhere, cost of purchasing resources, projected availability of resources, amount of stored resources, safety, regulatory and other factors in determining the best distribution of resources at any time.

In some embodiments the heat required by the Haber reactor can be produced by solar or geothermal energy. Temperature sensors in the Haber reactor measure the current temperature and the computer-based control system will use this information in concert with information derived from other sensors in the system such as bioreactor nitrogen sensors, hydrogen sensors and others to determine the heat and pressure to operate the Haber reactor in order to produce the amount of ammonia needed to satisfy current or future demand.

In some embodiments where renewable energy, such as solar, wind, tidal or geothermal is used to supply energy for hydrogen production, whether via creation of electricity, or heat for thermally driven processes, the current and anticipated availability of renewable energy may be used to determine how much ammonia and/or hydrogen to produce or store, and/or how much ammonia or hydrogen to obtain from other sources. The anticipated amount of renewable energy available can be determined at least in part by considering meteorological data, geospatial data, tidal, or other data collected outside of the system, as well as sensor data. This is true for any of the inputs which may vary in cost, availability, carbon footprint or other aspect. In some cases, the purchase of ammonia or hydrogen from suppliers will be facilitated or executed by the control system. A machine learning or artificial intelligence system such as mentioned above may be employed to determine optimized outcomes of production levels by the system, cost, carbon or environmental footprint, or a mix of these. This determination can then be used to adjust the conditions of the Haber reactor, hydrogen production rate, ammonia production, and to modify other conditions of the operation of the various parts of the system to achieve the desired outcome.

The system may be controlled or configured to achieve a desired condition such as maximum hydrogen utilization efficiency, maximum microbe growth efficiency, minimum environmental impact, lowest cost of operation, quality or yield of fermentation product or any other metric or set of metrics. The system can be upgraded via hardware changes, software changes or changes to the controllable elements to improve performance. Upgrades or changes to the system can be made based on the performance of other similar systems which are not in active communication with the control system.

In the foregoing specification, the invention is described with reference to specific embodiments thereof, but those skilled in the art will recognize that the invention is not limited thereto. Various features and aspects of the above-described invention may be used individually or jointly. Further, the invention can be utilized in any number of environments and applications beyond those described herein without departing from the broader spirit and scope of the specification. The specification and drawings are, accordingly, to be regarded as illustrative rather than restrictive. It will be recognized that the terms “comprising,” “including,” and “having,” as used herein, are specifically intended to be read as open-ended terms of art.