Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
  • B01D53/34—Chemical or biological purification of waste gases
  • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
  • C10J3/00—Production of combustible gases containing carbon monoxide from solid carbonaceous fuels
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12M—APPARATUS FOR ENZYMOLOGY OR MICROBIOLOGY; APPARATUS FOR CULTURING MICROORGANISMS FOR PRODUCING BIOMASS, FOR GROWING CELLS OR FOR OBTAINING FERMENTATION OR METABOLIC PRODUCTS, i.e. BIOREACTORS OR FERMENTERS
  • C12M43/00—Combinations of bioreactors or fermenters with other apparatus
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12M—APPARATUS FOR ENZYMOLOGY OR MICROBIOLOGY; APPARATUS FOR CULTURING MICROORGANISMS FOR PRODUCING BIOMASS, FOR GROWING CELLS OR FOR OBTAINING FERMENTATION OR METABOLIC PRODUCTS, i.e. BIOREACTORS OR FERMENTERS
  • C12M43/00—Combinations of bioreactors or fermenters with other apparatus
  • C12M43/02—Bioreactors or fermenters combined with devices for liquid fuel extraction; Biorefineries
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12P—FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE
  • C12P7/00—Preparation of oxygen-containing organic compounds
  • C12P7/02—Preparation of oxygen-containing organic compounds containing a hydroxy group
  • C12P7/04—Preparation of oxygen-containing organic compounds containing a hydroxy group acyclic
  • C12P7/06—Ethanol, i.e. non-beverage
  • C12P7/065—Ethanol, i.e. non-beverage with microorganisms other than yeasts
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
  • C25B1/00—Electrolytic production of inorganic compounds or non-metals
  • C25B1/01—Products
  • C25B1/02—Hydrogen or oxygen
  • C25B1/04—Hydrogen or oxygen by electrolysis of water
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
  • C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
  • C25B9/70—Assemblies comprising two or more cells
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
  • C10J2300/00—Details of gasification processes
  • C10J2300/09—Details of the feed, e.g. feeding of spent catalyst, inert gas or halogens
  • C10J2300/0913—Carbonaceous raw material
  • C10J2300/0946—Waste, e.g. MSW, tires, glass, tar sand, peat, paper, lignite, oil shale
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
  • C10J2300/00—Details of gasification processes
  • C10J2300/09—Details of the feed, e.g. feeding of spent catalyst, inert gas or halogens
  • C10J2300/0953—Gasifying agents
  • C10J2300/0959—Oxygen
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
  • C10J2300/00—Details of gasification processes
  • C10J2300/09—Details of the feed, e.g. feeding of spent catalyst, inert gas or halogens
  • C10J2300/0953—Gasifying agents
  • C10J2300/0969—Carbon dioxide
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
  • C10J2300/00—Details of gasification processes
  • C10J2300/09—Details of the feed, e.g. feeding of spent catalyst, inert gas or halogens
  • C10J2300/0983—Additives
  • C10J2300/0989—Hydrocarbons as additives to gasifying agents to improve caloric properties
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
  • C10J2300/00—Details of gasification processes
  • C10J2300/16—Integration of gasification processes with another plant or parts within the plant
  • C10J2300/1603—Integration of gasification processes with another plant or parts within the plant with gas treatment
  • C10J2300/1618—Modification of synthesis gas composition, e.g. to meet some criteria
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
  • C10J2300/00—Details of gasification processes
  • C10J2300/16—Integration of gasification processes with another plant or parts within the plant
  • C10J2300/164—Integration of gasification processes with another plant or parts within the plant with conversion of synthesis gas
  • C10J2300/1656—Conversion of synthesis gas to chemicals
  • C10J2300/1665—Conversion of synthesis gas to chemicals to alcohols, e.g. methanol or ethanol
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
  • C10J2300/00—Details of gasification processes
  • C10J2300/16—Integration of gasification processes with another plant or parts within the plant
  • C10J2300/1681—Integration of gasification processes with another plant or parts within the plant with biological plants, e.g. involving bacteria, algae, fungi
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
  • C10J2300/00—Details of gasification processes
  • C10J2300/16—Integration of gasification processes with another plant or parts within the plant
  • C10J2300/1684—Integration of gasification processes with another plant or parts within the plant with electrolysis of water
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
  • C10J2300/00—Details of gasification processes
  • C10J2300/18—Details of the gasification process, e.g. loops, autothermal operation
  • C10J2300/1807—Recycle loops, e.g. gas, solids, heating medium, water
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E50/00—Technologies for the production of fuel of non-fossil origin
  • Y02E50/10—Biofuels, e.g. bio-diesel
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E50/00—Technologies for the production of fuel of non-fossil origin
  • Y02E50/30—Fuel from waste, e.g. synthetic alcohol or diesel

Definitions

• the invention regards the field of processes and apparatuses suitable to convert RDF (Refuse Derived Fuel), MSW (Municipal Solid Waste) and similar materials such as plastic residues into products with higher added value by ensuring eco-compatibility in terms of absence of greenhouse gas emissions, and it specifically consists of a process and apparatus for producing bioethanol without CO 2 emissions by converting syngas obtained from the thermal conversion of waste at high temperature.
• RDF Refuse Derived Fuel
• MSW Mounicipal Solid Waste
• GHG greenhouse gas
• the conventional way to dispose of municipal, agricultural and industrial waste through incineration is also one of the main sources of greenhouse gas emissions, mainly CO 2 , CH 4 and nitrogen oxides.
• the waste can be used as a source of carbon and hydrogen by converting it into a syngas, a mixture of CO, CO 2 and H 2 .
• the processes for such a conversion are known in the art.
• patent WO/2018/066013 describes a gasification process through the use of pure oxygen for the conversion of waste into syngas controlling the temperature along the vertical axis of the reactor.
• Patent WO/2018/134853 describes a waste conversion process at high temperature for producing syngas, followed by the purification of the syngas and the regulation of the H 2 /CO ratio for the purpose of producing methanol.
• Patent US9518237 describes a process for converting a syngas into oxygenated hydrocarbon products through anaerobic bioconversion; said hydrocarbon products are in particular ethanol, acetic acid, n-propanol and n-butanol.
• Patent US2019/0078121 describes a different method for improving the CO/H 2 composition of the flow of gas available for supplying a microbial production of oxygenated compound.
• Refuse derived fuel is a sort of fuel produced after the separation of the organic fraction, metals, paper and plastic.
• the aim of the invention is to overcome the limits of the prior art by providing a process and apparatus which are compatible with the guidelines of the regulations aiming at reducing greenhouse gas emissions in the environment to zero and suitable for the conversion of municipal waste, together with other industrial waste, such as non-recyclable plastics, into bioethanol .
• the provided solution is a process, and the related apparatus, in which the CO 2 emissions are avoided due to the synergistic effect of a fermentation step and a methanation step, also by considering that it is well known that the gasification of such feed implies a greater production of CO and CO 2 , so as to produce a syngas which is enriched with extra hydrogen from electrolytic processes and thus maximizing the biological fermentation process for producing ethanol.
• Figure 1 shows a general conceptual diagram of the invention.
• Figure 2 shows a block diagram of a preferred embodiment of the invention with introduction of hydrogen upstream and downstream of the fermenter, and with units for refining the raw ethanol and purifying the recovered water.
• Figure 3 shows a block diagram of an alternative embodiment of the invention with introduction of hydrogen completely upstream of the fermenter.
• Figure 4 shows a detailed diagram of a preferred embodiment with introduction of hydrogen upstream and downstream of the fermenter.
• Figure 5 is an alternative embodiment with respect to figure 4 in which hydrogen is only introduced upstream of the fermenter.
• the present invention relates to a process for producing raw bioethanol by means of the fermentation of the syngas produced by the thermal conversion of the feed composed of one or more types of waste.
• the invention further describes an apparatus for carrying out the aforementioned process.
• waste such as, for example, ethanol
• said waste comprises Municipal Solid Waste (MSW), agricultural waste or derivatives thereof such as Refuse Derived Fuel (RFD) or even industrial waste, such as non-recyclable plastic waste.
• MSW Municipal Solid Waste
• RFD Refuse Derived Fuel
• industrial waste such as non-recyclable plastic waste.
• the process exploits the availability of hydrogen, produced by electrolysis, to allow the conversion into ethanol of the carbonaceous elements contained in the gasified waste.
• the availability of hydrogen produced by electrolysis further allows to avoid any emission of CO 2 into the atmosphere since any carbonaceous elements not converted during the fermentation step are converted into methane through a methanation reaction by simply adding further hydrogen; the methane thus produced can be sent for distribution or recycled to the gasifier to control the waste conversion temperature .
• the process developed originates from the consideration that the syngas produced by the high temperature conversion of municipal solid waste, treated or not, or by the thermal conversion of agricultural or industrial waste, has a H 2 /CO ratio by volume equal to about 1.
• the optimal H 2 /CO ratio required to produce ethanol by fermentation is about 2.0 2.2 by volume and thus it is obvious that the thermal conversion of waste, such as the above mentioned, which produces a syngas with a lower ratio value than the optimal one, would result into an excess of carbonaceous components which would come out from the process mainly in the form of carbon dioxide.
• the process comprises a plurality of high temperature waste converters able to produce the syngas and a plurality of electrolysis cells for producing hydrogen and oxygen.
• said methane can be used in the high temperature conversion of the waste for better control of the process and sent at the battery limits for use outside this process.
• the present invention relates to an eco-compatible process for producing ethanol from waste, through a step of fermentation of the syngas, said fermentation being optimized by adding extra hydrogen obtained through electrolysis of water whereas the oxygen of the same electrolysis is used as a comburent within the thermal conversion step, allowing to avoid the emission of CO 2 into the atmosphere.
• such a process comprises the following main steps:
• Said main steps can also include some further secondary steps such as:
• the step of high temperature conversion of waste to syngas (100) comprises multiple conversion trains, or reactors; more specifically it was chosen to use a minimum of two, preferably three, thermal conversion trains for converting the feed into syngas.
• Such a solution allows to correctly manage the maintenance period so as to ensure a certain continuity of use; thereby even when a single train is stopped for maintaining the other two trains, are able to work at a greater capacity, thus ensuring a minimum turndown (75- 80%) and continuous and almost constant operation for the steps downstream of the thermal conversion.
• the operating choice to perform thermal conversion on multiple trains allows to equalize the composition of the various streams of syngas leaving each gasifier before the subsequent purification step; this implies the possibility to modulate the feed with which each gasifier is supplied in order to obtain a raw syngas that is suitable to be treated in the subsequent purification step, increasing the flexibility of the plant.
• a flow rate of waste between 8 and 10 t/h was chosen, which is supplied to each individual thermal conversion line for an overall total of 24-30 t/h of convertible waste.
• Each thermal converter is supplied with pure oxygen, produced by the electrolysis process (102), as a gasifying agent; moreover, there is provided the introduction of a certain aliquot of natural gas (CH 4 ), recycled from the methanation step (105) and subsequent separation (106), for the purpose of controlling the temperature profile inside the reactor.
• CH 4 natural gas
• the stream of CO 2 can also advantageously be used for inerting the waste supply system thus preventing any syngas losses and any air infiltration; in the embodiment described it was chosen to use CO 2 as an inerting agent which is likely to be available within the streams that evolve in the process.
• Each conversion train consists of a conversion reactor which operates at almost atmospheric pressure (max 500 mbarg) and which dispenses syngas at a temperature of 1100-1200°C; said syngas is quickly cooled to 90°C through an evaporative quench which fixes the composition of the syngas obtained at high temperature inside the reactor avoiding triggering collateral reactions responsible for the formation of pollutants such as dioxins and furans.
• the invention includes, downstream of the thermal conversion unit (100), a purification step which acts at dual pressure (101), comprising multiple units according to the capacity of the plant, the aim of which is to remove particulate, metals, chlorides, ammonia, COS and H 2 S.
• the syngas leaving every gasifier is at a pressure approximately to atmospheric pressure, about between
• syngas is routed to an acid wash column operating at pH 1-3; these conditions allow removing any collected particles and metals from the syngas stream.
• the syngas outcoming from the three conversion trains at the outlet of the acid columns is collected together and routed to a common alkaline wash column which neutralizes it by increasing the pH above 7 and reducing any corrosion phenomena on the downstream equipment.
• a further purification step is carried out by means of a wet electrostatic precipitator (WEP) the aim of which is to remove the collected dust and which is possibly followed by a washing with subcooled water in a column with the aim of further reducing the dust and particulate in the syngas.
• WEP wet electrostatic precipitator
• a gas storage tank allows handling any flow rate and pressure fluctuations in the syngas; according to the invention the pressure at the gasometer is set at about 40 mbarg.
• the syngas Before entering the high pressure purification section, the syngas is compressed up to 12 barg through a dedicated compression unit; the pressurized syngas is then sent to an adsorbent bed with the aim of remove the residual dust, particulate and heavy metals.
• This operation is followed by a catalyst/adsorbent bed allowing the removal of HC1 and a hydrolysis reactor allowing the conversion of COS and HCN into H 2 S and NH 3 , respectively.
• the synthesis gas leaving from the hydrolysis reactor is sent to an Hg removal bed and to an H 2 S removal system according to known technologies.
• H 2 S can be carried out either through a system that allows the transformation of the H 2 S into elemental sulfur and then removed as sulfur sludge, or through amine washing.
• the syngas thus purified can be supplied to the ethanol fermentation section (103).
• the further hydrogen required to obtain an optimal H 2 /CO ratio is supplied by an electrolysis step (102) based on several cells, according to the capacity of the plant, suitable for the production of hydrogen and oxygen.
• part of the hydrogen produced by electrolysis is added to the syngas upstream of the fermentation step (103) and the remaining part is added downstream of the fermentation unit (103), before the methanation step (105) with the aim of optimizing both steps in terms of volume and operating conditions of the equipment involved; in an alternative embodiment, the stream of hydrogen produced in the electrolysis is fully added before the fermentation step (103) promoting the maximization of the conversion of CO and CO 2 into ethanol.
• the conversion of CO and CO 2 into ethanol is carried out in a fermentation step (103) in which said conversion is carried out in one or more bioreactors containing a bacterial culture dispersed in a liquid nutrient medium.
• the synthesis gas containing CO, CO 2 , added with the H 2 incoming from electrolysis is bubbled inside the liquid nutrient medium; the conversion causes the formation of dispersed ethanol in the nutrient medium in the aqueous phase and the production of a residual gaseous stream containing unreacted components and CO 2 generated by the biological conversion process during fermentation .
• the ethanol concentration in the stream outcoming from the fermentation step is comprised in the range between 3-6 %wt and thus it is required a specific step to separate ethanol from the aqueous phase in order to obtain anhydrous ethanol.
• the synthesis gas in addition with part of the hydrogen produced by electrolysis and therefore having an H 2 /CO ratio between 2.0 - 2.2 %vol, is converted into raw ethanol and a purge gas.
• the syngas in addition with all the hydrogen produced by electrolysis, will have an H 2 /CO ratio between 5 - 5.2 %vol thus converting CO and CO 2 into ethanol; according to this operating mode, the CO 2 initially contained in the syngas is converted during the fermentation process with a consequent increase in the yield of ethanol and a minimization of the purge gas stream.
• the purge gas produced by the fermentation step is further treated in the methanation step (105) in order to convert the CO 2 still present in the gas into methane preventing emissions into the environment.
• the remaining part of the hydrogen produced by electrolysis (102) is added to the stream of purge gas downstream of the fermentation step (103) in order to make the H 2 /CI optimal for performing the methanation of the amount of CO 2 still present in the purge gas and with the aim to produce synthetic methane; in the alternative embodiment described in which the hydrogen produced by electrolysis is fully added before the fermentation step, and thus generating a minimum amount of purge gas, the remaining amount of residue H 2 in the outcoming stream of purge gas at the outlet of the fermenter is sufficient for carrying out the methanation of residual CO and CO 2 without any further addition of fresh H 2 .
• the methane produced in step 105 is separated from any CO 2 unreacted in step 106, for the purpose of avoiding any emissions of CO 2 into the atmosphere.
• part of the methane is recycled to the conversion reactors (100) with the aim to control the temperature profile inside the reactors, while the remaining part is sent to other uses or sold externally .
• CO 2 is recycled in part to the methanation step (105) and in part to the thermal conversion step (100) as an inerting agent for the waste supply system; in particular in the alternative embodiment described, where the hydrogen from electrolysis (102) is fully added upstream of the fermenter (103), the amount of CO 2 recovered in the separation step (106) is low and not sufficient for inerting the waste supply system.
• a nitrogen-rich stream deriving from the known CO 2 separation process is used and which corresponds to a sub-product of the same block 106, as shown in fig. 5.
• the liquid phase outcoming from the fermenter, containing diluted ethanol, can be sent to the raw bioethanol, produced by fermentation, purification step (104) for recovering the product; in general this step typically includes the recovery of the biocatalyst, which is recycled again to the fermenter, and an ethanol recovery and purification step, generally carried out by means of several distillation columns, followed by dehydration through molecular sieve filtration in order to comply with the requirements on the residual water.
• a stream of anhydrous ethanol and a stream of water containing traces of alcohols produced during the fermentation process as sub-products are obtained; generally, such sub-products consist of butanediol, ethyl acetate and other higher alcohols.
• Said aqueous stream produced during the distillation step can be routed to a waste water treatment step (107) such as to allow the recycling of the water purified at the electrolysis step (102).
• the stream containing the sub-products consisting of butanediol, ethyl acetate and higher alcohols, and also the excess bacteria introduced into the fermenter (103), can be advantageously sent to the thermal conversion step (100); thereby, there is obtained the dual advantage of not dispersing organic components into the environment and further contributing to controlling the thermal conversion in terms of the composition of the raw syngas produced.
• the described process allows producing bioethanol from waste such as RDF, municipal solid waste, plastic residues and the like without introducing CO 2 into the atmosphere; indeed, the synergistic effect of the fermentation step followed by the methanation step of the purge gas produced during fermentation, allows to reduce, or completely break down, the amount of CO 2 in the outlet stream, thus avoiding introduction into the atmosphere.
• the methanation step does not completely remove CO 2 but preserves a certain amount thereof which is however separated downstream of methanation, thus preventing its introduction into the atmosphere; said recovered CO 2 stream is advantageously used to inert the waste supply system, thus preventing any syngas losses and any air infiltrations which would lead to lower conversion yields of the reactor with subsequent imbalances in the fermentation steps.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Organic Chemistry (AREA)
• Zoology (AREA)
• Wood Science & Technology (AREA)
• Life Sciences & Earth Sciences (AREA)
• Health & Medical Sciences (AREA)
• Bioinformatics & Cheminformatics (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Genetics & Genomics (AREA)
• Biotechnology (AREA)
• Microbiology (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Biochemistry (AREA)
• General Engineering & Computer Science (AREA)
• General Health & Medical Sciences (AREA)
• Biomedical Technology (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Electrochemistry (AREA)
• General Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Sustainable Development (AREA)
• Environmental & Geological Engineering (AREA)
• Inorganic Chemistry (AREA)
• Analytical Chemistry (AREA)
• Processing Of Solid Wastes (AREA)
• Preparation Of Compounds By Using Micro-Organisms (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Coke Industry (AREA)

Priority Applications (6)

Applications Claiming Priority (2)

Publications (1)

Family

ID=78212530

Family Applications (1)

Country Status (8)

Citations (3)

Family Cites Families (9)

• 2021
  • 2021-08-02 IT IT102021000020819A patent/IT202100020819A1/it unknown
• 2022
  • 2022-08-01 US US18/294,972 patent/US20240344092A1/en active Pending
  • 2022-08-01 ES ES22758022T patent/ES3033156T3/es active Active
  • 2022-08-01 EP EP22758022.2A patent/EP4363532B8/en active Active
  • 2022-08-01 WO PCT/IB2022/057126 patent/WO2023012644A1/en not_active Ceased
  • 2022-08-01 PL PL22758022.2T patent/PL4363532T3/pl unknown
  • 2022-08-01 MY MYPI2024000631A patent/MY210541A/en unknown
  • 2022-08-01 JP JP2024506514A patent/JP2024531104A/ja active Pending

Patent Citations (3)

Also Published As

Similar Documents

Legal Events