Removal and storage of carbon emissions through biolysis

Abstract

A method for removal and for removal and storage of carbon emissions through biolysis comprises the following steps: placing a mixture of biomass and water in an oxygen-free environment, and in that environment decreasing or increasing the temperature of the mixture and subjecting the mixture to a controlled pressure to thereby generate a saturated vapor, separating lighter fractions from the saturated vapor from heavier fractions to thereby obtain a fine water vapor with humic components dissolved in it, condensing the fine water vapor, collecting the condensate and realizing sedimentation of solid particles in order to obtain a solution of humic acids from the condensate, and lowering the pH of the solution and separating sediment resulting therefrom from the remaining fraction of the solution. Prior to the first step, the pH of the mixture of biomass and water is increased and clay catalysts and metal catalysts are added to the mixture.

Description

[0001] Title: Removal and storage of carbon emissions through biolysis

[0002] The invention relates generally to removal of carbon from the natural carbon cycle, with the underlying aim of reducing the carbon footprint.

[0003] The invention provides a new method of carbon dioxide removal (CDR, Carbon Dioxide Removal) that can be categorized as biomass-based carbon removal followed by storage of the product obtained (BiCRS, Biomass Carbon Removal and Storage). Currently, for the purpose of removing carbon from the air, a method combining biological energy with carbon dioxide capture and storage (BECCS, Bio Energy with Carbon Capture and Storage) is often applied. This method emphasizes energy production at the expense of some carbon dioxide removal. In this sense, produced energy can be seen as a missed opportunity to remove carbon. Bioenergy, obtained by burning wood, among other things, is wrongly promoted as a green energy solution in that context. Research has shown that emissions per unit of electricity from biomass can be even higher than from fossil fuels, depending on factors in the supply chain, such as biomass type, biomass moisture content and transportation distance. BECCS plants currently operate primarily with combustion or fermentation. Despite capturing some carbon dioxide, the plants are still net emitters, with emissions to supply the supply chain outweighing captured emissions. The carbon removal potential of BECCS is currently under debate, and BiCRS offers a new solution.

[0004] By shifting the primary focus from BECCS to BiCRS, i.e. , from bioenergy production to carbon removal, BiCRS solutions can be implemented on a regional or local scale in the short term. An important fact is that most likely within a few years the value of carbon is going to exceed the value of bioenergy, which means BiCRS solutions do not have to involve the sale of energy to be viable. Pyrolysis and biolysis are alternative, non-energy BiCRS solutions. Of these, biolysis offers the opportunity to look at the optimal mix for energy and carbon from a different perspective.

[0005] It is an objective of the invention to provide a BiCRS solution that is effective and cost-effective, and that allows full operation on sustainably generated green electricity. The stated objective is achieved through a method for removing carbon from biomass and fixing the carbon, comprising: - mixing the biomass with water and increasing the pH of the mixture, such as to a pH in a range of 8-12,

[0006] - adding clay catalysts and metal catalysts to the mixture of biomass and water, in that order,

[0007] - placing the mixture of biomass and water in an oxygen-free environment, and in that environment decreasing or increasing the temperature of the mixture, such as to a temperature in a range of 65°C-155°C, and subjecting the mixture to a controlled pressure, wherein the pressure may particularly be in a range of higher than 0.8 bar and lower than 1 .5 bar, in order to generate a saturated vapor from the mixture, in which phytonutrients from the plant cells that are part of the biomass are dissolved in a water fraction,

[0008] - separating lighter, fully soluble fractions from the saturated vapor from heavier, saturated fractions in order to obtain from the saturated vapor a fine water vapor with humic components dissolved in it,

[0009] - condensing the fine water vapor,

[0010] - collecting the condensate and realizing sedimentation of solid particles in order to obtain a solution of humic acids from the condensate, and

[0011] - lowering the pH of the solution containing humic acids and separating sediment resulting therefrom from the remaining fraction of the solution.

[0012] The invention provides a method which when carried out yields emissions containing carbon dioxide and carbon dioxide equivalents, capturing and sequestering the carbon dioxide and carbon dioxide equivalents. The amount of carbon dioxide to be captured and sequestered is calculated by comparing BECCS and BiCRS data and relating those to the available input for a given project. Carbon emissions, sulfur emissions and nitrogen emissions are captured and removed.

[0013] Further, when the invention is applied, marketable products such as humic acids (AHS, Accelerated Humic Substances or EHS, Enhanced Humic Substances) and hydrochar are produced. This is done in an oxygen-free environment, particularly in a reactor. Organic material such as green waste, manure and wood is fixed in the said humic acids and hydrochar during an oxygen-free reaction, under defined physiological / biochemical / thermal conditions. The invention eliminates oxidation (combustion) of biomass and also prevents metabolic processes of microorganisms from taking place, unlike what is normally the case in nature and during digestion, fermentation and composting. The process is a form of bio-mimicry, converting organic matter to fixed carbon, except that the biolysis process takes a few hours rather than many centuries. The final product hydrochar is a pure form of carbon that has not been subjected to decomposition, digestion, fermentation, oxidation or combustion.

[0014] A device configured to perform the method according to the invention, which may be characterized as a method for removal and storage of carbon emissions through biolysis, may comprise in particular the following components:

[0015] - a reactor for receiving and containing the mixture of biomass and water,

[0016] - mechanisms for controlling the temperature in the reactor, controlling the pressure in the reactor, and ensuring low oxygen conditions in the reactor,

[0017] - a vapor handling system for receiving the saturated vapor, separating lighter, fully soluble fractions from the saturated vapor from heavier, saturated fractions, and discharging fine water vapor thus obtained,

[0018] - a condenser unit for receiving and condensing the fine water vapor, and

[0019] - a phase separator for receiving and fractionating the condensate.

[0020] The device may be designed for batch implementation of the method for removal and storage of carbon emissions through biolysis, but it is also possible that the device may be designed for continuous implementation of the method. In practice, the latter option will usually be preferred. For example, the device may be designed to process 20 tons of biomass per day in a continuous process.

[0021] In the following, a process is described as a practical example of what is possible in the context of the invention. Biomass derived from streams of waste, including manure, verge waste and kitchen waste, is mixed with water and a light chemical component with pH increasing effect. After a time period in the order of an hour, the mixture is ground into a slurry and introduced into the reactor through an automatic feed system. Relatively hard waste such as wood waste is first presoaked, for example for a day, wherein optionally amylase (enzymes) may be added as an accelerator.

[0022] Under a pressure which is atmospheric pressure or near atmospheric pressure, particularly just below atmospheric pressure, that is to say, under sub- atmospheric (vacuum) conditions, or just above atmospheric pressure, that is to say, under slightly elevated pressure conditions, and a temperature which is at most 155°C, a cracking process is initiated in the reactor, during which the phytonutrients are extracted from the biomass cells and dissolve in the water fraction of the mixture. It is an insight of the invention that the elevated pH combined with time and temperature causes the cells to open without the need for high pressure. The reactor is heated with propane or by other means such as solar or green electricity. The slurry is continuously stirred by an agitator in the reactor which initially slowly raises the temperature to the boiling point of water. The reactor then continues to operate at the same operational temperature, producing vapor containing extracted phytonutrients dissolved in it.

[0023] Heating with propane is the least harmful in terms of carbon dioxide and significantly cheaper than electric heating. It is possible to add application of microwaves (MAE, Microwave Assisted Extraction) or ultrasound (UAE, Ultrasound Assisted Extraction) to the pretreatment to open up the cells so that the reaction time can be shorter.

[0024] According to the invention, use is made of catalysts so that as many as possible phytonutrients are dissolved and can eventually be converted to humic fractions or their precursors. After the pH of the slurry has been increased, clay catalysts are added first, and metal catalysts are added later. A practical example of a clay catalyst is bentonite.

[0025] The clay catalysts have a negatively charged surface, and are therefore useful to protect the amino acids, phenols and saccharides as they adhere to the clay. The clay catalyzes hydrolysis of hemi-cellulose and pectins, stimulates condensation reactions and activates polymerization of fulvene-like structures. De catalyst action is based on creating a kind of matrix (structure formation of the molecules on the basis of valence) in which the humic and fulvene precursors are assembled, while humic formation is accelerated. The pretreatment time varies strongly with the constitution of the biomass. For example, at room temperature and with a long residence time, which may be in a range of one hour to an entire day, possibly combined with agitation, phenols, organic acids and the clay become bio-inspired humic complexes.

[0026] The metal catalysts are added to the biomass slurry at a later stage. These catalysts may comprise iron salts, other metals than iron, and pure iron powder. During the pretreatment process and also the biolysis process in the reactor, iron compounds (chelates and hydroxides) are formed. These are mild Fenton reactions which can take place in the pretreatment process, due to availability of oxide and moisture, and to a lesser extent in the reactor. These mild oxidation reactions initiate the humic formation process, wherein especially the fulvene fractions are obtained as desired for the production of bio-stimulants and replacement of artificial chelates. It is beneficial if the metal catalysts are also present in the vapor handling system, albeit in lesser amounts, and react with the vapor. Synergy between the catalysts brings about controlled decomposition of cell structures and release of humic precursors.

[0027] During the heating process many water-soluble humic acids and fulvene-like substances are formed. Phytonutrients such as flavonoids, phenolic acids and lignin fragments are modified to shorter, water-soluble chains which subsequently react with iron to chelates, while the clay absorbs all intermediate products and facilitates aggregation to fulvene complexes. This yields a condensate including soluble humic precursors, iron-fulvene complexes and fulvic acids having a low molecular weight. Thus, this contains organic acids, complexes and the humic / fulvic acids having a low molecular weight.

[0028] Thus, the metal catalysts are used to improve condensation at low temperatures and low pressure and to promote redox reactions. This helps to bind amino and phenolic groups (to promote Fenton reactions which in this case generate reactive hydroxyl radicals acting to oxidize a wide range of organic compounds into humic substances). Increase of the pH is realized in a bio-organic way because of the produced hydroxyl radicals. In the reactor, iron chelates with the humic substance which is released during the process and remains stable. The fulvic acid has chelated iron as an important component. The clay catalysts absorb volatile organic compounds and ammonia (in case animal manure is processed) and create agromineral complexes in the final product. The clay catalysts increase the cation exchange capacity and bind nutrients and agro-minerals in a stable way. The clay catalysts also improve the porosity and prevents a possible collapse of the microstructure during carbonization of the final product.

[0029] When the pressure in the reactor is set at a value which is lower than atmospheric pressure, such as 0.8 bar, the boiling point of water is reduced, so that the thermal energy which is required to induce evaporation within the reactor is lowered. It appears in practice that applying a vacuum via a dedicated valve and vacuum pump, combined with modifications to the respective control mechanism (and associated PLC programming, for example), allows for moisture evaporation at significantly reduced temperatures, wherein the temperatures may be as low as 65 °C, more or less without compromising separation efficiency. Conversely, when operating at pressures in a range of 1 .2 to 1 .5 bar, the temperature of the slurry may reach a value which is between 110°C and 130°C, which favors enhanced solubilization and reaction kinetics for certain fractions. Preliminary experimental trials have demonstrated that vacuum-assisted evaporation is feasible.

[0030] The vapor handling system may comprise a coke drum with a rectification column above it. The hot water vapor rises and exits the reactor at an upper end of it through the coke drum. In the vapor handling system, lighter, fully soluble fractions are passed through to the condenser unit, while the heavier, saturated fractions, with any solid particles that do not reach suspension, are returned to the reactor for further extraction and separation. Advantageously, the coke drum is designed as a cyclone arrangement configured to remove solid particles and return those to the reactor under influence of gravity. It is further possible that the rectification column contains catalytic packing and a demister pad including metal catalysts such as ironbased catalysts.

[0031] The condensed vapors are described as produced humic acids (AHS, Accelerated Humic Substances or EHS, Enhanced Humic Substances). These are collected in the phase separator. Here, solid particles (humic) settle, oil is separated through a natural skimming process and the humic acids remain in solution. The humic acids are then further processed to achieve separation of humic and fulvic acids. To this end, the pH of the solution is lowered by adding a light chemical component. The humic acid settles while the fulvic acid remains in solution. Through centrifugation and filtration, the fractions are separated and collected in separate tanks. The molecular composition of the humic acid and fulvic acid varies such that these acids can be traded as two different products, with the fulvic acid having a significantly higher value than humic acid. The particles that do not dissolve during the cracking process and remain in the reactor are primarily mineral found carbon components (hydrochar). The hydrochar is automatically drained from the reactor and is dry. The hydrochar is an interesting end product with economic value.

[0032] It follows from the above that the reactor is the place in the device where biomass with an elevated pH is received and brought to a higher temperature and pressure creating a saturated vapor. It is practical when an agitator is used to keep the biomass composition and temperature in the reactor homogeneous. Stirring also achieves good mixing of the biomass with the pH increasing agent. The vapor passes through the coke drum to the rectification column, with heavier particles (that are not in suspension) falling back into the reactor. For the rectification column, at a certain temperature, only a fine water vapor containing the dissolved humic components (polyphenols, saponins, polysaccharides, alkaloids, fatty acids, amino acids, terpenes, etc.) passes through the column. Heavier particles re-enter the reactor through the coke drum for further treatment. In the condensing unit, the vapor condenses to liquid humic substances, and in the phase separator, by reducing the pH, separation of humic acid and fulvic acid is accomplished.

[0033] As suggested above, a unique aspect of the method according to the invention is that no pressure is applied to extract the contents of the biomass cells. Chemistry in conjunction with temperature and residence time are the key variables in the process. Conventionally, pressure is applied as a variable. This is used to obtain a rapid progression of the process, allowing more biomass to be processed in a shorter time. Surprisingly, however, it turns out that it is not necessary to increase pressure significantly. Additional advantages are then that the quality of the outgoing products increases and that it is not necessary to apply pressure vessels so that risks are reduced.

[0034] The aforementioned and other aspects, features and advantages of the invention will be further clarified by the following description, wherein reference will be made to the drawing, wherein equal reference numerals indicate equal or similar parts, and in which: figure 1 diagrammatically shows a perspective view of a practical embodiment of a plant according to the invention, configured for removal and storage of carbon emissions through biolysis; and figure 2 is a diagram of components of the plant and connections between the components.

[0035] Figure 1 schematically shows a perspective view of a practical embodiment of a plant 100 according to the invention, configured for removal and storage of carbon emissions through biolysis, in the manner already described in the foregoing. In the figure a number of components of this plant 100 can be distinguished, including a reactor 10, a vapor handling system 20, a condenser unit 30, a phase separator 40 and a biomass system 60. These components are located in a frame structure 101.

[0036] Figure 2 is a diagram of the above-mentioned and more components of the plant 100 and connections between them. The following is an explanation. Connected to a feed 11 for the reactor 10 is the biomass system 60 with a shredder 61 , a feed 62 for solid biomass to the shredder 61 , a feed 63 for water to the shredder 61 , and two tanks 64, 65 for taking the mixture from the shredder 61 and soaking the mixture. A suitable pumping system may be provided for moving the mixture from the shredder 61 to the two tanks 64, 65. The tanks 64, 65 are also connected to a feeder 66 for material usable for process activation. Further material to be added to the mixture comprises clay catalysts and metal catalysts such as iron chloride and fine iron powder. A screw hopper 67 and a pump 68 are provided to receive the mixture from the tanks 64, 65 and convey it to the feed 11 for the reactor 10, which comprises a hopper.

[0037] A conduit 51 leading from the reactor 10 to a chimney 50 for exhausting gases from the reactor 10 includes a heat recovery unit 52 for extracting heat from the gases moving through this conduit 51. A blower 53 is provided for supporting flow in this conduit 51 .

[0038] A burner 12 is provided at the reactor 10, and an agitator 13 is provided in the reactor 10. Further, a screw system 14 for carbon removal is connected to the reactor 10.

[0039] A vessel 31 for collecting liquid is connected to the condenser unit 30. The liquid is fed via a pump 32 and a valve system 33 as desired to a receptacle 34 of the liquid for recovery and cleaning, which receptacle 34 is provided with a drain 35, to the feed 11 for the reactor 10, and to a reactor with mixer 70 connected via a pump 71 to the phase separator 40 for extracting humic acids from the liquid. Optionally, the liquid can be drained directly from the vessel 31 through a drain 36 of the vessel 31.

[0040] The phase separator 40 comprises a pressure filter 41 for separating humic, a stabilization tank 42 in which the pH of the humic acids is lowered, an acid supply 43 for the stabilization tank 42, lines 44, 45 with tanks 46, 47 at the end for separately collecting humic and fulvic acid in liquid form from the stabilization tank 42, and also a centrifuge 48 connected to lines 44, 45. To generate the various flows required in the phase separator 40, a pump 80 is provided behind the pressure filter 41 . Valve systems 81 , 82, 83 are also used in the phase separator 40 to direct the various flows as appropriate.

[0041] Both the humic separated in the pressure filter 41 and semi-solid material from the centrifuge 48 are fed to a dryer 85. This dryer 85 is heated with heat extracted by the heat recovery unit 52 from the gases flowing from the reactor 10 to the chimney 50. Behind this dryer 85 is a unit 86 for carbon removal. This allows the plant 100 to produce dry, solid carbon as a usable end product during operation, as well as at least humic acid and fulvic acid in liquid form.

[0042] It will be clear to a person skilled in the art that the scope of the invention is not limited to the examples discussed in the foregoing, but that various changes and modifications thereof are possible without departing from the scope of the invention as defined in the appended claims.

Claims

CLAIMS1 . Method for removing carbon from biomass and fixing the carbon, comprising:- mixing the biomass with water and increasing the pH of the mixture,- adding clay catalysts and metal catalysts to the mixture of biomass and water, in that order,- placing the mixture of biomass and water in an oxygen-free environment, and in that environment decreasing or increasing the temperature of the mixture and subjecting the mixture to a controlled pressure in order to generate a saturated vapor from the mixture, in which phytonutrients from the plant cells that are part of the biomass are dissolved in a water fraction,- separating lighter, fully soluble fractions from the saturated vapor from heavier, saturated fractions in order to obtain from the saturated vapor a fine water vapor with humic components dissolved in it,- condensing the fine water vapor,- collecting the condensate and realizing sedimentation of solid particles in order to obtain a solution of humic acids from the condensate, and- lowering the pH of the solution containing humic acids and separating sediment resulting therefrom from the remaining fraction of the solution.

2. Method as claimed in claim 1 , wherein in the oxygen-free environment, the mixture of biomass and water is subjected to a pressure which is in a range of higher than 0.8 bar and lower than 1 .5 bar.

3. Method as claimed in claim 1 or 2, wherein in the oxygen-free environment, the temperature of the biomass is decreased or increased to a temperature in a range of 65°C-155°C.

4. Method as claimed in any of claims 1-3, wherein the pH of the mixture of biomass and water is increased to a pH in a range of 8-12.

5. Method as claimed in any of claims 1-4, wherein metal catalysts are also added to the saturated vapor.

6. Method as claimed in any of claims 1-5, wherein energy for the purpose of increasing the temperature of the biomass in the oxygen-free environment is obtained through combustion of propane.

7. Method as claimed in any of claims 1-6, wherein the biomass is stirred.

8. Method as claimed in any of claims 1-7, wherein the biomass is soaked in water prior to increasing the pH.

9. Method as claimed in any of claims 1-8, wherein the biomass is ground into a slurry prior to placing the biomass in the oxygen-free environment.

10. Method as claimed in any of claims 1-9, wherein separating sediment from the remaining fraction of the solution is established through centrifugation and filtration.11 . Device (100) configured to configured to perform the method as claimed in any of claims 1-10, comprising:- a reactor (10) for receiving and containing the mixture of biomass and water,- mechanisms for controlling the temperature in the reactor, controlling the pressure in the reactor, and ensuring low oxygen conditions in the reactor,- a vapor handling system (20) for receiving the saturated vapor, separating lighter, fully soluble fractions from the saturated vapor from heavier, saturated fractions, and discharging fine water vapor thus obtained,- a condenser unit (30) for receiving and condensing the fine water vapor, and- a phase separator (40) for receiving and fractionating the condensate.

12. Device (100) as claimed in claim 11 , wherein the vapor handling system (20) comprises comprise a coke drum with a rectification column above it, wherein the coke drum is designed as a cyclone arrangement configured to remove solid particles and return those to the reactor under influence of gravity.

13. Device (100) as claimed in claim 12, wherein the rectification column contains catalytic packing and a demister pad including metal catalysts.

14. Device (100) as claimed in any of claims 11-13, wherein the mechanism for controlling the temperature in the reactor comprises a propane burner (12).

15. Device (100) as claimed in any of claims 11-14, wherein an agitator (13) is located in the reactor (10).

16. Device (100) as claimed in any of claims 11-15, comprising separate tanks (46, 47) for receiving and containing different fractions separated from the condensate.

17. Device (100) as claimed in any of claims 11-16, comprising a dryer (85) for drying output material from the phase separator (40), and a heat recovery unit (52) for extracting heat from chimney gases and supplying the heat to the dryer (85).

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