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
  • B01D53/84—Biological processes
  • B01D53/85—Biological processes with gas-solid contact
• • C—CHEMISTRY; METALLURGY
  • C05—FERTILISERS; MANUFACTURE THEREOF
  • C05F—ORGANIC FERTILISERS NOT COVERED BY SUBCLASSES C05B, C05C, e.g. FERTILISERS FROM WASTE OR REFUSE
  • C05F17/00—Preparation of fertilisers characterised by biological or biochemical treatment steps, e.g. composting or fermentation
  • C05F17/10—Addition or removal of substances other than water or air to or from the material during the treatment
  • C05F17/15—Addition or removal of substances other than water or air to or from the material during the treatment the material being gas
• • C—CHEMISTRY; METALLURGY
  • C05—FERTILISERS; MANUFACTURE THEREOF
  • C05F—ORGANIC FERTILISERS NOT COVERED BY SUBCLASSES C05B, C05C, e.g. FERTILISERS FROM WASTE OR REFUSE
  • C05F17/00—Preparation of fertilisers characterised by biological or biochemical treatment steps, e.g. composting or fermentation
  • C05F17/80—Separation, elimination or disposal of harmful substances during the treatment
• • 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
  • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
  • Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
  • Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
• • 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
• • 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
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P20/00—Technologies relating to chemical industry
  • Y02P20/141—Feedstock
  • Y02P20/145—Feedstock the feedstock being materials of biological origin
• • 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
  • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
  • Y02W30/00—Technologies for solid waste management
  • Y02W30/40—Bio-organic fraction processing; Production of fertilisers from the organic fraction of waste or refuse

Definitions

• the present invention refers to a process for removing methane from landfill biogas streams.
• the present invention refers to a process for removing methane from landfill biogas streams and/or bioaerosols.
• the present invention also refers to a biofiltering unit for removing methane from landfill biogas streams and/or bioaerosols .
• the present invention also refers to a plant for removing methane from landfill biogas streams and/or bioaerosols comprising at least one biofiltering unit.
• waste is normally tapped by a collecting network;
• the term "landfill biogas” means a mixture of different kinds of gases that spontaneously forms by anaerobic bacterial fermentation of organic material, mainly with generation of methane (the so-called methanisation of the organic compounds) as well as and of carbon dioxide and molecular hydrogen .
• Biogas that contains methane and/or other combustible contaminants with concentrations higher than 25 % can be used for generating electric power, for instance by conveying it to a cogeneration system, or it can be burned, for instance by torch combustion.
• biogas that contains methane and/or other combustible contaminants with concentrations lower than 25 % is usually released to the atmosphere.
• methane is a greenhouse gas over twenty times more dangerous than carbon dioxide: the emission of 1 kg of CH 4 , on a time frame of 100 years, is equivalent to emit 21 kg of C0 2 .
• the technical problem faced by the aforesaid document concerns, besides the generation of thermal energy, the transfer and utilisation of the generated thermal energy, but it does not concern the methane removal from landfill biogas streams and/or bioaerosols.
• composting processes which involve the aerobic decomposition of organic material, generally release negligible amounts of methane and that, therefore, the problem of treating landfill biogases for removing methane and/or other combustible contaminants therein contained, and the problem of biofiltering the gaseous streams exiting the composting plants substantially to remove smells therefrom, are distinct technical problems. Solutions allowing the purification of the landfill biogas insufficient to be used for electric purposes or to be torch burned are known in the reference technical fields; some of such solutions provide for removing the so-called “poor" biogas through biofiltration before their final release to the atmosphere.
• Biofiltration is a biological process for removing methane and the smells contained in the gaseous stream that uses a natural removal process carried out by a heterogeneous microbial population present on the surface of the filtering bed.
• the microbial flora metabolises the most of the organic and inorganic compounds by means of a series of oxidative reactions that convert the inlet organic compounds into reaction products that are no longer smelling and less dangerous from the environmental point of view.
• the biological oxidation reaction of methane is the following :
• reaction products are carbon dioxide, water, new biomass and energy produced in the form of heat.
• the operating principle of a biofilter provides for using a heterogeneous microbial population consisting of, for instance, bacteria, actinomycetes and fungi that, by colonising the filtrating matrix, are able to metabolise the substances present in the gaseous effluents passing therethrough, irrespective of whether they are natural or synthetic, inorganic or organic, aliphatic or aromatic compounds.
• bioaerosols that is of vapours and powders containing moulds, bacteria and other organisms potentially bad, at high concentration, for the health of people working near the plants.
• Aspergillus fumigatus has an optimum growth temperature of about 37 °C.
• the present invention intends to overcome drawbacks and limitations of the prior art solutions and to meet the still unsatisfied need for a solution for the biological treatment of the "poor" biogas extracted from landfills that allows to minimise, and even to nullify, the release of the methane contained in the biogas into the surrounding environment.
• the present invention intends to meet the still unsatisfied need for a solution for the biological treatment of the "poor" biogas extracted from landfills that guarantees optimum humidity and temperature conditions for the biological process and minimises, or even nullifies, the release of the methane contained in the biogas into the surrounding environment.
• the present invention also intends to meet the still unsatisfied need for a solution for the biological treatment of bxoaerosols.
• biofiltering unit and the relevant plant and process, used for removing landfill biogas and/or bxoaerosols according to the invention that, advantageously because being equipped with a double covering, allows to obtain optimum humidity and temperature conditions for the biological process and to minimise, and even to nullify, the release of the methane contained in the biogas into the surrounding environment as well as to decrease bioaerosols .
• the biofiltering unit according to the invention comprises said double covering comprising, in its turn, a permeable sheet, equipped with a suitable supporting system, and a cover.
• the solution according to the invention allows to treat the biogas also at the first cultivation stage of the landfill, when a conventional system is not yet active, as well as at the production "tail" stage, when a conventional system is no more applicable.
• FIG. 1 is a front perspective view of the biofiltering unit according to the invention.
• FIG. 2 is a rear perspective view of the biofiltering unit according to the invention.
• FIG. 3 is a top perspective view of the biofiltering unit according to the invention.
• FIG. 4 is a front view, with open door, of the preferred embodiment of the biofiltering unit according to the invention.
• FIG. 5 is a side view of FIG. 4;
• FIG. 6 is a section taken along line A-A of FIG. 5;
• FIG. 7 is a section taken along line B-B of FIG. 6;
• FIG. 8 is a top view of the supporting system of the permeable sheet of the double covering of the biofiltering unit according to the invention.
• FIG. 9 is a section taken along line A-A of FIG. 8;
• FIG. 10 is a top plan view of FIG. 5, which shows the wetting system of the biofiltering unit according to the invention ;
• FIG. 11 is a section taken along line B-B of FIG. 10;
• FIG. 12 is a section taken along line A-A of FIG. 10, which shows the condensate and leachate collection and discharge system of the biofiltering unit;
• FIG. 13 is an enlargement of detail D of FIG. 12, which shows the condensate storage gutter of the biofiltering unit according to the invention.
• FIGS. 1, 2 and 3 show a biofiltering unit 1 for removing landfill biogas according to the invention.
• Said biofiltering unit 1 preferably comprises a roll-off container; according to a variant of the invention, said biofiltering unit 1 may comprise a marine container.
• Said biofiltering unit 1 preferably made as standard- version, may also be provided with flameproof protection.
• the roll-off container 2 of the biofiltering unit 1 is provided with ribbings 20 and it is preferably made of steel, more preferably of Fe 360 steel; preferably, said container 2 has an epoxy painting both on the outside and on the inside surfaces thereof, the outside painting being able to be personalised with logos and or drawings for instance made of metal or aluminium, adhesives, serigraphated, etc..
• said container 2 has a size of about 6.5 m x 2.5 m x 2.65 m, equal to a useful internal volume of about 22 m 3 .
• the roll-off container 2 of the biofiltering unit 1 comprises an openable cover 3, an inlet 4 for the biogas to be purified, a condensate and leachate collection and discharge system 5 and at least two sliding rolls 10; preferably, said container also comprises a first stairway 11 to facilitate the access to the cover top from the front side.
• the roll-off container 2 of the biofiltering unit 1 further comprises a charge/discharge door 6 and a housing 7 for the electrical panel of the adjustment and control system of the biofiltering unit 1; preferably, said container also comprises a second stairway 12 to facilitate the access to the cover top from the rear side.
• the roll-off container 2 of the biofiltering unit 1 further comprises a photovoltaic solar panel 8, preferably adjustable in height, for supplying the electrical occupancies and a chimney 9, preferably equipped with backflow cap 9a and sleeve 9b for sampling and measuring emissions; said panel 8 and said chimney 9 are accessible through said first stairway 11 and said second stairway 12 respectively .
• biofiltering unit 1 The preferred embodiment of the biofiltering unit 1 according to the invention will be now described in detail with reference to FIGS. 4 to 13.
• the roll-off container 2 of the biofiltering unit 1 is visible in FIG. 4, said container comprising an openable cover 3, an inlet 4 for the biogas to be purified, a condensate and leachate collection and discharge system 5, a charge/discharge door 6, a housing 7 for the electrical panel of the adjustment and control system of said biofiltering unit 1 (better visible in FIG. 5) , a photovoltaic solar panel 8 for supplying the electrical occupancies and a chimney 9, preferably equipped with backflow cap 9a and sleeve 9b for sampling and measuring emissions, at least two sliding rolls 10 and ribbings 20.
• Said inlet 4 for the biogas to be purified is preferably made of stainless steel and it is connected to the collecting network, as shown.
• Said photovoltaic solar panel 8 is preferably adjustable in height, as illustrated by the dotted line in figure, in order to maximise the exploitation of the solar energy depending on the change of the sun position.
• Said cover 3 is preferably of the flag-kind, as illustrated by the dotted line in figure, and it is preferably openable through a manual oleodynamic lifting system.
• Said cover 3 is accessible through the second stairway 2 provided on the rear side of said container 2, as it is well visible in FIG. 5. It is clear that any kind of stiff covering, even not fastened to the container 2 (such as, for instance, an independent roof) , known to the person skilled in the field can replace said cover 3 for the purposes of the present invention .
• the roll-off container 2 further comprises a settling chamber, or plenum, 13 placed in the lower part thereof; the biogas to be purified is blown into said settling chamber 13 through said inlet .
• the double covering 3, 30 and the ventilation bottom 40 are visible; the filtering matrix 50 is also represented in figure.
• Said permeable sheet 30 preferably consists of a fabric coupled with a plastic film, said coupling being preferably carried out by means of sticking, thermal welding or other known techniques.
• Said fabric of said permeable sheet 30 is preferably either a natural fibre fabric, such as hemp or cotton, or a synthetic fibre fabric, such as acrylic, polyester or polyamide fibres; more preferably said fabric of said permeable sheet 30 is polyester .
• Said plastic film of said permeable sheet 30 preferably consists of a plastic, for instance polyethylene or PVC, film with very small pores, preferably having diameter ⁇ 2 micron.
• Said double covering 3, 30 of the biofiltering unit 1 performs the combined action of an element preserving the humidity of said filtering matrix 50, specifically performed by said cover 3, and of an additional filter for the gas wastes, specifically performed by said permeable sheet 30; particularly, said permeable sheet 30 also allows to remove bioaereosols because of the plastic film structure, whose pores are smaller than the bioaerosols spores and that, therefore, acts as a "sieve" and, consequently, as a filter.
• Said double covering 3, 30 of the biofiltering unit 1 further allows an optimal protection against the atmospheric agents, such as UV rays, wind, rain and other inclement weather conditions, as well as the full segregation from the surrounding environment, which helps the installation thereof possibly also in zones next to areas of human settlement.
• atmospheric agents such as UV rays, wind, rain and other inclement weather conditions
• FIG. 7 clearly shows the pipe forming the inlet of the biogas to be treated in the biofiltering unit 1, the ventilation bottom 40 and the supporting system 33 of said permeable sheet 30.
• Said ventilation bottom 40 substantially consists of a holed paving made of modular grid tiles 41, preferably made of glass-fibres reinforced polypropylene and preferably having plan unit size of 500 x 500 mm, and of frusto-conical supports 43, preferably made of polypropylene and preferably being 500 mm high; thanks to the implemented construction type, said ventilation bottom 40 is removable, this helping the cleaning and maintenance operations of the biofiltering unit, and it turns out to be suitable to assure a low speed proper passage of the forced air as well as the homogeneous distribution of said air inside said biofiltering unit.
• a constructive variant of the ventilation bottom 40 can consist of steel plates.
• Said biofiltering matrix 50 preferably consisting of a preconstituted mixture, comprising ligno-cellulosic oversize material coming from composting processes, compost, peats and other materials, with the addition of additives such as microbial inocula and/or organic/inorganic specific activators for optimising the biological activity inside the filtering material, is placed above said ventilation bottom 40.
• biofiltering matrix 50 has the following characteristics:
• a forced air ventilation for instance by means of a fan (not shown), is preferably provided.
• Said supporting system 33 of the permeable sheet 30 is illustrated in detail with reference to FIGS. 8 and 9.
• Said supporting system 33 consists of a series of truss-beams
• Said truss-beams 23 are preferably made of stainless steel; said truss-beams 23 are provided to be removable to facilitate the recurring replacement of the biofiltering matrix 50.
• the permeable sheet 30 is placed on the structure formed by the truss-beams 23 and anchored, along its perimeter, to a suitable frame 25, said frame too being preferably made of stainless steel and fastened to container 2 by means of known methods, for instance by welding.
• Said support system 33 of the permeable sheet 30 has optimum lightness characteristics, combined with a good assembly easiness and with realisation and installation limited costs.
• a constructive variant of the supporting system 33 of the permeable sheet 30 can consist of independent frames to be applied to the frame of the truss-beams 23; in this case the anchoring frame 25 of the permeable sheet will appear to be unnecessary and, in its whole, the structure will become even lighter .
• Said support system 33 also supports the wetting system 60, used for wetting the filtering matrix 50 of the biofiltering unit 1 and shown in detail in FIGS. 10 and 11.
• Said biofiltering matrix 50 can be periodically wetted, for instance with water preferably coming from a nozzle system 66, preferably having a temporised opening, mounted above the surface of said biofiltering matrix 50; the wetting frequency and intensity can be settled and changed depending on the requirements of the specific application.
• the above-mentioned increase in terms of yield, obtained thanks to the presence of the wetted permeable sheet 30, is in the order of 10-30 % with optimum humidity and temperature conditions of the biofiltering unit 1, that is with humidity of 50-65 % and temperature of 20-60°C.
• the condensate storage gutter 35 of the biofiltering unit 1 is visible; said gutter is connected to the collection and discharge system 5.
• the condensate and leachate discharge pipe is equipped with a threaded ring.
• the activity of the biofiltering unit 1 can be monitored through the measurement of parameters such as, for instance, flowrate, concentration and temperature of the inlet biogas; concentration of the outlet biogas; temperature, relative humidity and pressure gradient between inlet and outlet of the biofiltering matrix.
• the monitoring/adjusting system of the operative main parameters of the biofiltering unit 1 is preferably housed, according to the preferred embodiment of the invention, inside the housing 7.
• Said system can be put in connection with the chimney 9, specifically with the sleeve 9b for sampling and measurement of the emissions, and also with the wetting system 60, so as to obtain an integrated and fully automated detecting/monitoring/adjusting system for controlling the management parameters.
• the methane concentrations at the entrance into and at the exit from the system, the inlet biogas flowrate, the amounts of wetting water, the inlet biogas and the biofiltering material temperatures could be monitored.
• Said system can further comprise a GSM modem, for transmitting data by sms .
• Said system is supplied by the photovoltaic solar panel 8 placed on the top of the biofiltering unit 1.
• biofiltering unit 1 guarantees the removal of smelling impact; the olfactometric surveys carried out according to UNI EN 13725-2004 regulation, have in fact highlighted a removal efficiency higher than 90 % of the inlet olfactometric units.
• the biofiltering unit 1 according to the invention helps to reduce the greenhouse gas (GHG) emissions since a single biofiltering unit allows to remove the methane contained in the landfill biogas in measure up to about 4,400 tons/year of C0 2 equivalent, varying depending on the biogas flowrate and on the inlet methane concentration; it has been however assessed that the average contribution of a single biofiltering unit according to the invention is equivalent to the positioning of about 1,700 trees/year on a land area of 1.7 hectars.
• GSG greenhouse gas
• a plant for removing landfill biogas and/or bioaerosols according to the present invention comprises at least one biofiltering unit 1.
• biofiltering units 1 in order to meet the actual requirements for biogas treatment, it is possible to combine two or more biofiltering units 1 as above described; thanks to the modularity of said biofiltering units, the system turns out to be easily adaptable to the specific applications and the overall treatment efficiency can be improved.
• Said plant will comprise, furthermore, at least a feed system of the biogas to be treated, a system of release to the atmosphere of the purified biogas and in case other ancillary apparatuses, such as mixers and fans, known to the person skilled in the field and, therefore, not described in detail herein .
• said plant can be provided with a predilution device, or mixer, of the biogas to be treated with ambient air, in order to produce a mixture wherein the concentration of the methane entering said biofiltering unit 1 is approximately within the threshold of 25 % v/v; said biogas is fed to said mixer preferably through a fan, and said biogas/air mixture is then conveyed to the biofiltering unit 1, which carries out the purification thereof and from which a purified gas stream containing a reduced methane amount is discharged.
• a predilution device or mixer
• the predilution system of the inlet biogas uses the Venturi principle.
• the object of the dilution with ambient air, besides lowering the inlet methane concentrations, is also to be able to enrich the biogas with oxygen, in case the concentration of said element is too low.
• said plant can also comprise an external energy source, whose main function will be to supply electrical apparatuses (for instance, thermal exchangers) that will allow to maintain the inlet biogas temperature, and therefore the biofiltering material temperature too, always optimal, with the result of maintaining high performances of methane removal.
• electrical apparatuses for instance, thermal exchangers
• said process for purifying biogases and/or removing bioaerosols further comprises the following steps: providing a wetting system 60, supported by said supporting system 33 and equipped with a nozzle system 66, preferably having a temporised opening;
• said process for removing landfill biogases and/or bioaerosols according to the invention further comprises the following step:
• said process for removing landfill biogases and/or bioaerosols according to the invention further comprises the following step:
• a particularly advantageous aspect of the biofiltering unit, as well as of the relevant plant and process, used for removing the landfill biogas according to the present invention consists in its excellent operative flexibility; in particular : the biofiltering unit according to the invention allows to treat the biogas streams in the production initial stage, when the energy recovery systems can not be employed yet;
• the biofiltering unit according to the invention makes the biogas reduction possible at the stage following the landfill closure, when the conventional systems are no longer used.
• the biofiltering unit according to the invention can be employed in the production final stage in order to optimise the biogas purification together with the energy recovery systems, thus allowing the purification of biogas streams not suitable to the energetic recover.
• biofiltering unit as well as the relevant plant and process, used for removing the landfill biogases according to the present invention, herein described by means of preferred embodiments given by way of non- limiting example, can be modified according to ways known to the person skilled in the technical field without, for this reason, departing from the scope of the present invention.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Health & Medical Sciences (AREA)
• General Chemical & Material Sciences (AREA)
• Molecular Biology (AREA)
• Life Sciences & Earth Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Biotechnology (AREA)
• Microbiology (AREA)
• Biochemistry (AREA)
• Organic Chemistry (AREA)
• Biomedical Technology (AREA)
• Environmental & Geological Engineering (AREA)
• Toxicology (AREA)
• Analytical Chemistry (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Separation Using Semi-Permeable Membranes (AREA)
• Processing Of Solid Wastes (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=42236686

Family Applications (1)

Country Status (3)

Families Citing this family (3)

Family Cites Families (7)

• 2009
  • 2009-10-05 IT ITTO2009A000756A patent/IT1396293B1/it active
• 2010
  • 2010-10-01 WO PCT/IB2010/054442 patent/WO2011042846A1/en active Application Filing
  • 2010-10-01 EP EP20100773988 patent/EP2485826A1/de not_active Withdrawn

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events