The present disclosure provides a gas collection apparatus. The present apparatus may be used, for example, in devices, systems and methods for processing biomass. For instance, the present apparatus may be used in pyrolytic systems and methods of producing biochar, torrefied wood, or biocoal.
There is an increasing interest in fuel derived from biomass such as forestry, agricultural products or construction or demolition waste. There are various technologies for converting biomass to fuel such as direct burning, co-firing, gasification, fermentation, pyrolysis, and the like. Depending on the feedstock and the process used the resultant product will have different utilities and properties. In many cases, it is desired to produce a product to replace a fossil fuel leading to sustainability and environmental benefits.
Pyrolysis is a type of thermal decomposition in which a substance is heated in the absence of oxygen. Pyrolysis may be termed ‘fast’, ‘slow’ or ‘mild’ depending on the target temperature, the heating rate and the residence time of the biomass. In the case of dried biomass, the pyrolysis can result in decomposition into three major products: biochar (also known as biochar), bio-oil, and syn-gas. In the case of ‘mild’ pyrolysis or torrefaction, woody biomass decomposes into two major products: torrefied wood (also known as biocoal) and a process gas similar to syngas. The development of efficacious technology that enables the pyrolytic conversion of lower-value biomass into higher energy bio-fuels and products (biocoal, biochar and bio-oil) is desirable. In particular, it is of interest to provide technology for the production, optimization, and delivery of bio-fuels, particularly biochar and biocoal, to be used in various agricultural, forestry, and industrial applications that can benefit from using bioproducts and renewable fuel sources.
Pyrolysis for the conversion of biomass into fuel products are described, for example, in CA 2,242,279 which discloses an apparatus for continuous charcoal production; which CA 2,539,012 discloses a closed retort charcoal reactor system; and CA 2,629,417 which discloses systems and methods for the continuous production of charcoal by pyrolysis of organic feed.
The disclosure provides a gas collection apparatus. The present apparatus may be used, for example, in a system for producing biocoal or biochar or bio-oil from biomass. The present gas collection apparatus may be part of a thermochemical biomass reactor. The present gas collection apparatus may be part of a syngas management system.
Embodiments of the present disclosure relate to a gas collection apparatus for fluidly communicating with a retort of a biomass reactor, said collection apparatus comprising two or more gas collection pipes in fluid communication with spaced apart sections of said retort; and a gas collection manifold in fluid communication with said pipes. The gas collection apparatus is designed such that the gases collected by one pipe do not mix with those collected by another within the piping network.
Embodiments of the present disclosure relate to a collection apparatus for fluidly communicating with a retort of a biomass reactor, said collection apparatus comprising two or more gas collection pipes in fluid communication with spaced apart sections of said retort; wherein said sections relate to different temperature zones within the reactor. For example, the zones may correspond to the temperatures at which hemicellulose, cellulose, and/or lignin decompose within the reactor. Embodiments the present apparatus may comprise three or more collection pipes in fluid communication with zones which correspond to hemicellulose, cellulose, and lignin decomposition within the reactor.
Embodiments of the present disclosure relate to a collection apparatus for fluidly communicating with a retort of a biomass reactor, said collection apparatus comprising two or more gas collection pipes in fluid communication with spaced apart sections of said retort; wherein the gas collection pipes are heated. Such heating may, for example, reduce unwanted condensation within the collection pipes.
Certain embodiments of the present apparatus enable the collection of off-gases and vapours from various locations along the path of material flow in a reactor used for the pyrolysis or torrefaction of biomass. These off-gases may be comprised of numerous chemical constituents that evolve from the biomass during pyrolysis or torrefaction, and can cause tar formation or coking deposits that can degrade or block the off-gas piping. The chemical constituents can be separated by their boiling and dew points and evolve from the biomass as its internal temperature increases. At least in part, the present disclosure provides an apparatus that enables the collection of off-gases grouped within a range of boiling points, and their conveyance away from a reactor. Embodiments of the present apparatus reduce the incidence of deposits forming in the off-gas piping.
As used herein, the term ‘biomass’ refers to material derived from non-fossilized organic material, including plant matter such as lignocellulosic material and animal material such as wastes, suitable for conversion into biofuels.
As used herein, the term ‘pyrolysis’ refers to thermal decomposition in which a substance is heated in the absence of substantial amounts of oxygen.
As used herein, the term ‘biomass reactor’ refers to a chamber suitable for performing pyrolysis or torrefaction of biomass.
As used herein, the term ‘gas collection apparatus’ refers to an exhaust manifold comprising two or more pipes adapted to fluidly communicate with a retort of a biomass reactor. The gas collection apparatus may comprise a common gas collection area but the apparatus is designed such that the gases collected from the retort do not mix in the piping network.
As used herein, the term ‘biochar’ or ‘biocoal’ refers to pyrolyzed biomass. Generally biochar will have a calorific value of about 15 MJ/Kg or greater, such as about 17 MJ/Kg or greater, or about 19 MJ/Kg or greater, about 21 MJ/Kg or greater, about 23 MJ/Kg or greater, about 25 MJ/Kg or greater, about 27 MJ/Kg or greater, about 29 MJ/Kg or greater.
As used herein, “a” or “an” means “one or more”.
This summary does not necessarily describe all features of the invention. Other aspects, features and advantages of the invention will be apparent to those of ordinary skill in the art upon review of the following description of specific embodiments of the invention.
In the accompanying drawings, which illustrate one or more exemplary non-limiting embodiments:
The present disclosure provides, at least in part, gas collection apparatus adapted to fluidly communicate with a retort of a biomass reactor.
The reactor may have at least one retort extending through it. For example, the reactor may have two, three, four, or more retorts. The retort comprises a suitable biomass conveyor such as, for example, an auger or paddle conveyor, an inlet and an outlet. The inlet receives biomass which passes through the reactor by way of the conveyor to the outlet. The reactor further comprises a heating system which preferably indirectly heats the biomass as it passes through the reactor. The heating system can heat the biomass to a temperature suitable to cause pyrolysis of biomass. The heating system may be any suitable design such as, for example, a plurality of heating elements, heat exchangers, or burners throughout the length of the reactor.
Gases exit the retort(s) via the present gas collection apparatus. The apparatus comprises at least two gas collection pipes in fluid communication with, and dispersed along at least a portion of, the retort(s) such that gases developed in the retort(s) during the pyrolysis process enter the pipes and are carried out of the reactor. Where the reactor comprises more than one reactor chamber it is preferred that each retort have at least two separate gas collection pipe(s). The separate pipes may feed into a gas collection module such as, for example, a gas storage tank, thermal oxidizer or burner. It has been found that having separate pipes running from different sections of the retort that correspond with a particular biomass temperature and thermochemical stage of decomposition (see, for example,
The present disclosure provides a syn-gas management system comprising; at least two gas collection pipes in communication with a retort of a biomass reactor, the gas collection pipes in communication with a gas collection module, a syn-gas storage tank having an inlet and an outlet, said inlet in communication with the gas collection module, and said outlet in communication with a heating system for the reactor.
The present reactor may comprise one or more thermosensors. The thermosensors monitor the temperature within the reactor and thus the temperature may be kept at the appropriate level to achieve the desired result. Multiple sensors allow for more accurate assessment of the temperature at different points in the reactor. Based on the temperature reading the heating may be increased or decreased.
The present reactor may comprise one or more additional sensors such as, for example, a sensor for sensing the speed of the conveyor. This sensor enables the controller to assess the speed with which the biomass is moving through the reactor chamber and determine the residence time for the process. If this speed is too slow the controller may speed up the conveyor or if the speed is too fast the controller may slow the conveyor down.
The present gas collection pipes may comprise one or more thermosensors. The thermosensors monitor the temperature within the pipes and thus the temperature may be kept at the appropriate level to achieve the desired result. Multiple sensors allow for more accurate assessment of the temperature at different points in the pipe. The pipes may be configured for heating such as, for example, by applying heating tape. Based on the temperature reading the heating may be increased or decreased.
In certain embodiments, the reactor produces a solid biochar stream (biocoal or biochar) and a gaseous stream. Biocoal can have utility as a fuel source, and biochar can have utility as a soil additive, or the like. The gaseous stream is collected via the present gas collection apparatus and may comprise condensable and non-condensable components. The condensable components may, for example, be condensed to form pyrolysis oil (bio-oil). Bio-oil may be used as a petroleum substitute. The non-condensable gases (syn-gas) may be combustible and used, for example, to fuel the reactor heating system.
The present system may comprise a solids delivery system for receiving the biocoal/biochar exiting the reactor. The delivery system receives the biochar stream from the retort via the outlet. The system may include a biocoal/biochar cooling means. Any suitable cooling means may be used such as direct contact with a cooling medium, indirect contact with a cooling medium, direct contact fluid quenching, or the like. For example, the means may be an auger which moves the hot biochar through a cooling zone and on to densification and/or bagging areas. An airlock such as a rotary valve airlock may be positioned between the cooling zone and the compaction/bagging area, or just after the outlet. The cooling of the biocoal/biochar may be aided by the application of a liquid such as water.
It is possible enrich the biochar with additives such as nutrients or minerals. The resultant biochar could derive advantageous properties from such enrichment. For example, when used as a soil additive the addition of nutrients and minerals markedly improves the performance of the product. Examples of minerals include, but are not limited to, nitrogen, sulphur, magnesium, calcium, phosphorous, potassium, iron, manganese, copper, zinc, boron, chlorine, molybdenum, nickel, cobalt, aluminum, silicon, selenium, or sodium. Examples of nutrients include compost tea, humic and fulvic acids, plant hormones, and other solutions of benefit to plant growth and soil health such as buffers, pH conditioners, and the like.
The addition of the additives to the biochar may be achieved in any suitable manner. For example, additives may be applied at the biochar delivery system. Additives can be introduced to the cooling liquid and applied to the biochar at the cooling zone. As the cooling liquid boils off the additives can be left behind on the char. Additives may be introduced as a solid and, for example, incorporated through mixing in the cooling zone.
The present reactor may include a biomass dryer module. The drying can receive biomass feedstock and may comprise a moisture sensor. The dryer receives biomass and dries it to reduce the moisture content. Preferably, the moisture content is about 20% or less, about 18% or less, about 15% or less. The dryer may be, for example, a flash dryer, a belt dryer, or a drum dryer. Once the desired moisture content is reached the biomass can be fed into the retort via the inlet means. A rotary valve airlock may be used between the dryer and the reactor in order to control the delivery of the biomass. In an embodiment of the present disclosure hot air from the reactor can be used in the dryer thus reducing the need for external heat sources in the dryer and improving the overall efficiency of the system
Any suitable biomass feedstock may be used herein such as, for example, those comprising wood fibre, agricultural fibre, by-products or waste (from plant or animal sources), municipal waste, or the like. The selection of biomass may vary depending on availability, the desired output and the particular application. Softwood-fibre typically comprises three major components: hemicellulose (25-35% dry mass), cellulose (40-50% dry mass), and lignin (25-35% dry mass). The energy content of wood fibre is typically 17-21 GJ/tonne on a dry basis
The feedstock may be in particulate form and may have an average particle size of from about 1 mm to about 50 mm, such as from about 5 mm to about 25 mm. It is preferred that the feedstock have a moisture content of about 15% or less, such as about 10% or less, before commencement of pyrolysis.
Depending on the nature of the biomass it may be necessary to prepare the feedstock prior to pyrolysis. For example, the certain feedstocks may require grinding to produce particles of an appropriate particle size and/or shape. The present method may comprise a moisture removal step where the feedstock is heated to such a temperature that moisture is driven off.
The present disclosure provides a system for pyrolysis of biomass, the system comprising:
(a) a reactor having a retort extending therethrough, said retort comprising a conveyor, an inlet, and an outlet; the reactor further comprising at least one thermosensor, the thermosensor capable of generating a signal when the temperature is below optimal levels;
(b) a heating system adapted to heat the reactor;
(c) a syn-gas management system; the management system comprising at least two gas collection pipes in communication with said retort, the gas collection pipes in communication with a gas collection module, a syn-gas storage tank having an inlet and an outlet, said inlet in communication with the gas collection module, and said outlet in communication with the heating system and syn-gas outlet such as a flare or storage tank; and
(d) a controller in communication with the reactor and the syn-gas outlet; wherein the controller switches the valve modulate the speed of the conveyor, and the temperature of the heating tape on the syngas manifold, upon receiving a signal from the thermosensor that the temperature in the reactor is above optimal levels.
In certain preferred embodiments of the present gas collection pipes are heated. It has been found that heating the pipes can help to reduce the amount of unwanted condensation in the present apparatus.
When in use the present reactor may comprise a hemicellulose decomposition step. The hemicellulose decomposition step may be at a temperature of from about 200° C. to about 280° C., such as about 220° C. to about 260° C. The temperature may vary throughout the step or may stay constant. For example, the temperature may be increased at a rate of about 100° C./min or less, about 50° C./min or less, about 35° C./min or less, about 20° C./min or less, about 15° C./min or less, about 10° C./min or less. The step may continue for any suitable length of time such as, about 1 minute or more, about 2 minutes or more, about 3 minutes or more, about 4 minutes or more, about 5 minutes or more, about 10 minutes or more. It is preferred that by the end of the pyrolysis at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, of the mass of hemicellulose in the feedstock has been decomposed. It is preferred that at least a portion (preferably the majority) of the gases formed from the pyrolysis of hemicellulose be conveyed in a common pipe. The pipe may be heated to reduce condensation.
When in use the present reactor may comprise a cellulose decomposition step. The cellulose decomposition step may be at a temperature of from about 240° C. to about 400° C., such as about 300° C. to about 380° C. The temperature may vary throughout the step or may stay constant. For example, the temperature may be increased at a rate of about 100° C./min or less, about 50° C./min or less, about 35° C./min or less, about 20° C./min or less, about 15° C./min or less, about 10° C./min or less. The step may continue for any suitable length of time such as, about 1 minute or more, about 2 minutes or more, about 3 minutes or more, about 4 minutes or more, about 5 minutes or more, about 10 minutes or more. It is preferred that by the end of the pyrolysis at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, of the mass of cellulose in the feedstock has been decomposed. It is preferred that at least a portion (preferably the majority) of the gases formed from the pyrolysis of cellulose be conveyed in a common pipe. The pipe may be heated to reduce condensation.
When in use the present reactor may comprise a lignin decomposition step. The cellulose decomposition step may be at a temperature of from about 280° C. to about 500° C., such as about 400° C. to about 500° C. The temperature may vary throughout the step or may stay constant. For example, the temperature may be increased at a rate of about 100° C./min or less, about 50° C./min or less, about 35° C./min or less, about 20° C./min or less, about 15° C./min or less, about 10° C./min or less. The step may continue for any suitable length of time such as, about 1 minute or more, about 2 minutes or more, about 3 minutes or more, about 4 minutes or more, about 5 minutes or more, about 10 minutes or more. It is preferred that by the end of the pyrolysis at least about 5%, at least about 10%, at least about 15%, at least about 20%, of the mass of lignin in the feedstock has been decomposed. It is preferred that at least a portion (preferably the majority) of the gases formed from the pyrolysis of lignin be conveyed in a common pipe. The pipe may be heated to reduce condensation.
Yields of biocoal, biochar, bio-oil, and syn-gas can be altered by varying the process temperatures and/or heat transfer rates. While not wishing to be bound by theory, it is believed that higher temperatures tend to favour the production of bio-oil and/or syn-gas by driving off more of the condensable volatiles produced from decomposition of cellulose. Conversely, mild pyrolysis may favour the production of biocoal by limiting the decomposition of cellulose and reducing the amount of bio-oil produced. Biocoal production can generally be maximized at temperatures of approximately 285° C. It is believed that at these temperatures hemicellulose still decomposes into syn-gas while much of the cellulose remains as a solid within the lignin matrix. By limiting the decomposition of the cellulose fraction, mass yields of biocoal can be increased to around 70%. This type of pyrolysis is known as torrefaction and the resulting biochar is referred to as torrefied wood or biocoal. Producing torrefied wood leads to a reduced amount of bio-oil thus reducing the issues associated with storing and handling such oil.
Certain embodiments according to the present disclosure may provide biocoal or biochar yields in the range of from about 20% to about 80%, such as about 25% to about 70%. In general, higher yields are seen with torrefaction than with other types of pyrolysis. Certain embodiments according to the present disclosure may provide bio-oil yields in the range of from about 10% to about 40%, such as about 20% to about 50%.
Referring now to
At least a portion of the gaseous stream is collected by the gas collection apparatus 8 which comprises two pipes leading to a gas collection manifold at the outlet end of the retort. The gas collection pipes are spaced apart on the retort to collect gases from different areas. For example, the pipes may be positioned based on the inherent differences in boiling points. The gases are then fed into a condenser 10 which can condense condensable components such as bio-oil. The condensed bio-oil is collected in a bio-oil collection tank 17 which the gaseous stream is fed to a three-way valve 19. Depending on the needs of the furnace 6 the valve can direct the gas to a flare 18 or to syn-gas burners 9 via syn-gas pipe 20.
Biochar at the downstream end of retorts 7 is collected and delivered to a cooling retort with a water jacket and auger 13. The assembly comprises a coolant (water) tank 11 and an additive tank 12. The water and/or additive are applied to the biochar via spray nozzles 14. Cooled and improved biochar is the delivered to a collection bin 16 controlled via a rotary valve airlock 15.
Referring now to
Referring now to
It is contemplated that the different parts of the present description may be combined in any suitable manner. For instance, the present examples, methods, aspects, embodiments or the like may be suitably implemented or combined with any other embodiment, method, example or aspect of the invention.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as is commonly understood by one of ordinary skill in the art to which this invention belongs. Unless otherwise specified, all patents, applications, published applications and other publications referred to herein are incorporated by reference in their entirety. If a definition set forth in this section is contrary to or otherwise inconsistent with a definition set forth in the patents, applications, published applications and other publications that are herein incorporated by reference, the definition set forth in this section prevails over the definition that is incorporated herein by reference. Citation of references herein is not to be construed nor considered as an admission that such references are prior art to the present invention.
Use of examples in the specification, including examples of terms, is for illustrative purposes only and is not intended to limit the scope and meaning of the embodiments of the invention herein. Numeric ranges are inclusive of the numbers defining the range. In the specification, the word “comprising” is used as an open-ended term, substantially equivalent to the phrase “including, but not limited to,” and the word “comprises” has a corresponding meaning.
The invention includes all embodiments, modifications and variations substantially as hereinbefore described and with reference to the examples and figures. It will be apparent to persons skilled in the art that a number of variations and modifications can be made without departing from the scope of the invention as defined in the claims. Examples of such modifications include the substitution of known equivalents for any aspect of the invention in order to achieve the same result in substantially the same way.
Filing Document | Filing Date | Country | Kind |
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PCT/CA2014/050297 | 3/20/2014 | WO | 00 |
Number | Date | Country | |
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61803739 | Mar 2013 | US |