CA2741266C - Device for drying solid biomass and use of said device - Google Patents

Abstract

The invention relates to a solid biomass drying device comprising a plurality of cyclones (1A to 1E) arranged in series, each cyclone comprising a conical lower part, of which a first upper cyclone (1A) comprises a biomass feed pipe ( 6) and a gas outlet pipe (3A) and whose other cyclones (16 to 1E) comprise an inlet pipe (4B to 4E) and an outlet pipe (3B to 3E) of the gas, each cyclone comprising a lower vertical flow (5A to 5E) of flow of solids to the ceiling of the adjacent cyclone. According to the invention, said first cyclone (1A) also comprises a hot gas supply pipe (2) opening into the ceiling of the upper cyclone (1A) and said gas inlet pipe (46 to 4E) of the other cyclones also leads into the ceiling of the corresponding cyclone.

Description

Application No .: 2,741,266 Attorney Docket No .: 11559-011 SOLID BIOMASS DRYING DEVICE AND USE THEREOF
DEVICE
The invention relates to a device for drying solid biomass and a use of this device.
In the context of climate change and the imposition of quotas emissions of carbon dioxide emitted by industrial installations and especially energy production based on solid fossil fuels, it appears that capture and the storage of carbon dioxide that is envisaged in the medium and long term for the large facilities will be insufficient to meet the factor four of division of carbon dioxide emissions in 2050.
The capture and storage of carbon dioxide will have to be supplemented by the use of agricultural and forestry biomasses for capacity medium and lower which are able to collect these biomasses in an area limited geographical area.
These biomasses of natural origin have the disadvantage of high levels in humidity, which has a penalizing effect on the efficiency of conversion both combustion and gasification. Knowing that efforts Technological be made on all stages of the thermochemical conversion of the biomass it is necessary to improve the performance of the drying step and to avoid drying is emitting specific emissions of carbon dioxide.
It is known in industries that use biomass of the type manufacture of particle boards, to perform this drying in rotary kiln, powered by fumes produced by generators powered by natural gas. These fumes allow to reduce the starting moisture of the biomasses, which is 55 to 60%, at around 20 to 25 A, at the price expensive energy consumption and carbon dioxide.
The use of a rotary kiln is a primary technique of gas contact solid and compact, known for average drying performance of biomass. On the other hand, it has the advantage of tolerating biomasses coarse and to be well adapted to papermaking chips but to be limited by sawdust fines.

Application No .: 2,741,266 Attorney Docket No. 11559-011 There are also technologies in development for the drying of high moisture lignite produced in dense fluidized bed possessing submerged heat exchangers traversed by steam. But these technologies are adapted to lignite of small particle size, intended for combustion in the state pulverized very fine.
US patent document 2005/0274067 discloses a drying device for biomass as a fuel in a cement plant. The vintage of cement plant containing these biomasses is dried in a preheating section comprising a series of cyclone-type preheating stages, the raw material being introduced into the cyclone and the hot gas from a rotary kiln being introduced into the cyclone lower, the drying being carried out against the current of solids and gases.
The upper cyclone preheater receives the solids via a pipe horizontal side also bringing the gas at the end of the gas loop and the solid separate gases flow from one cyclone to another through a vertical pipe less than cyclones. The lower cyclone preheater receives the hot gas through a conduct lateral horizontal at the beginning of gas loop.
Such a drying device poses the following technical problems.
Such a drying device is very bulky, each cyclone having a diameter of the order of 10 meters and the total height of the series of cyclones being of the order of 80 meters, and can not be installed in any place.
Counter current drying applies exclusively to a type cement plant where the supply of hot gas is low.
The invention solves these technical problems and proposes a device for drying specifically for biomass, which is compact and particularly integrated into a rapid fluidized bed thermochemical conversion plant, while ensuring a strong mixing turbulence with hot gases.
To do this, the invention proposes a device for drying solid biomass comprising a plurality of cyclones arranged in series, of which a first cyclone superior includes a biomass supply line and a exit from the other cyclones have an inlet pipe and a conduct of gas outlet, each cyclone having a lower vertical pipe flow solids to the ceiling of the adjacent cyclone, characterized in that said first

-2-Application No .: 2,741,266 Attorney Docket No. 11559-011 cyclone also includes a hot gas supply duct opening in the ceiling of the upper cyclone and the said gas inlet pipe of the others cyclones also leads into the ceiling of the corresponding cyclone.
The invention also relates to a device for drying solid biomass comprising a plurality of cyclones arranged in series, each cyclone with a conical lower part, of which a first upper cyclone comprises a conduct of hot gas entering the ceiling of the upper cyclone and a conduct gas outlet, each cyclone having a lower vertical pipe flow of solids to the ceiling of the adjacent cyclone, characterized what said first upper cyclone comprises a biomass feed pipe, others cyclones include an inlet pipe and a gas outlet pipe and said other cyclone's gas inlet pipe also leads into the ceiling of corresponding cyclone.
To improve the thermochemical conversion yields of biomass and reduce their humidity to about 10%, moisture equivalent to that of fuels coal-type solid fossils, it is necessary to carry out a drying putting in strong mixing turbulence with hot gases containing oxygen and possibly solids, without igniting these biomasses and a time sufficient residence for these migrations of moisture in the particles porous biomass that have been prepared in granulometry. An improvement of performances requires reducing the particle size spectrum of input biomass for control their residence time and make it homogeneous. The compactness of the drying device is essential to reduce investment costs.
The invention also relates to a use of such a drying device of solid biomass, characterized in that said hot gas is taken from fumes from combustion or on synthesis gas at a temperature of about 600 to 700 C.
The invention finally relates to a use of such a drying device of solid biomass, characterized in that inert solids are mixed with the biomass fed and are recovered at the outlet of the drying device to be recycled in the biomass fed.

-3-Application No .: 2,741,266 Attorney Docket No. 11559-01 1 The invention further relates to the use of a drying device of biomass solid as described above, characterized in that it is installed in a bed loop fluidized fluid comprising a reactor, an associated separation cyclone and a conduct back of the solids of this cyclone to the reactor, said pipe gas supply hot being fed by gases withdrawn at the outlet of said cyclone of separation.
The invention is described below in more detail with the aid of FIGS.
representative that a preferred embodiment of the invention.
FIG. 1 is a schematic view in elevation of a drying device of biomass according to the invention.
FIG. 2 is a detailed perspective view of such a device for drying of biomass according to the invention.
FIG. 3 is a top view of detail of such a drying device of biomass according to the invention.
FIG. 4 is a schematic plan view of a conversion installation thermochemical fast fluidized bed equipped with a drying device biomass according to the invention.
As illustrated in FIG. 1, a device for drying solid biomass, according to the invention, comprises a plurality of high speed cyclones arranged in series, five cyclones IA to 1 E according to the example shown, each cyclone with a conical lower part and a cylindrical upper part.
A first cyclone IA comprises a hot gas supply pipe 2 and a gas outlet pipe 3A and the other cyclones 1B to JE comprise a conduct input 4B to 4E and an outlet line 3B to 3E of the gas. Every cyclone includes a lower vertical pipe 5A to 5E of flow of the solids towards the ceiling of adjacent cyclone, arranged on the axis of symmetry of the corresponding cyclone.
The hot gas supply pipe 2 opens into the roof of the cyclone upper IA and the inlet line 4B to 4E of the other cyclones gas leads also in the corresponding cyclone ceiling.

-4-Application No .: 2,741,266 Attorney Docket No. 11559-01 The feed pipe 2 and the inlet lines 4B to 4E of the gas are inclined at least 20 to the horizontal in a final section in part high of the corresponding cyclone and flow directed downwards The outlet pipe 3B to 3E of the gas is arranged laterally to the conical part of the corresponding cyclone and inclined downwards.
The biomass is fed in the upper cyclone 1A by a pipe vertical 6 disposed on the axis of symmetry of this cyclone.
The plurality of cyclones 1A to 1E is arranged in a tower, their axes of symmetry being aligned in a line X. This arrangement minimizes the frame of support.
The drying gas containing the moisture evaporated at the outlet of the last cyclone 1E, discharged through the outlet pipe 3E, is directed to filtration and condensation for reuse of water and then transfer to a downstream process of transformation or release to the atmosphere after possible treatment of volatile substances contained.
Figures 2 and 3 show in more detail the outlet pipes and input gas between two cyclones 1B and 1C. On these figures are also represented them lower vertical pipes 5A and 5B of solid flow correspondents.
The 4C gas inlet line opens into the roof of cyclone 1C at near the periphery of the latter preferably by a slot in an arc of a circle, width constant. The outer peripheral edge of this slot is arranged in continuity with the cylindrical wall of cyclone 1C, so as not to reduce the speed of solid.
Cyclone 1B has a lateral flue outlet pipe 3B, by its lower conical part.
3B outlet line and 4C inlet line are connected in one line unique that has a minimum length connection geometry to connect the inclined lateral outlet pipe 3B of gas through the lower cone of the cyclone 113 with the 4C hot gas inlet line to cyclone ceiling following I C.
The inclined exit pipe section 3B is followed by a section of conduct vertical stroke 7 and the inclined inlet pipe section 4C. Of preferably, a angle of 45 in a horizontal plane of projection is arranged between the stretch of

-5-Application No .: 2,741,266 Attorney Docket No. 11559-01 inclined lateral outlet pipe 3B of cyclone 1B and the section of inlet pipe inclined 4C at the ceiling of the adjacent cyclone 1C.
According to a preferred use of this solid biomass drying device, the hot gas introduced into the feed pipe 2 is taken from gases from a combustion plant, for example air combustion, oxy-fuel combustion or cycle thermochemical, or on synthesis gas, at a temperature of about 600 to 700 C.
Advantageously, to improve the contacting of the hot gases with the biomass to dry, inert solids that can act as coolants, for example sands, clays, circulating ashes or minerals, are mixed with biomass fed by the pipe 6 and are recovered at the outlet of the device drying, separated by partial sieving of the dried biomass, for recycling into the biomass at dry fed at the top of the drying device, as illustrated by a dotted line 16 in Figure 1.
This loop of inert solids mixed with biomass to dry with the gases warm favors flows by rinsing ducts, between cyclones successive and increases contact with biomass to accelerate drying kinetics.
FIG. 4 illustrates an example of use of this drying device of solid biomass.
This solid biomass drying device, comprising for example two cyclones 1A and IB in series, is installed in a fluidized bed loop fast featuring a reactor 10, an associated separation cyclone 11 and a return pipe 12 of from this cyclone to the reactor, the gas supply pipe 2 hot being fed with gases withdrawn at the outlet of the separation cyclone 11.
The dried biomass is fed via line 6 and at the outlet of the device of drying, evacuated via line 5B, is injected into the bottom of the reactor 10.
The gas of drying with evaporated moisture at the outlet of the last cyclone 1B, is evacuated by 15. Solids are withdrawn from the return line 12 and, after cooling by an exchanger 13 at a temperature of about 600 C to 700 C, are mixed by means of a biomass line 14 fed to the device of drying, by driving 6.

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Claims (9)

1. Solid biomass drying device comprising a plurality of cyclones (1A to 1E) arranged in series, each cyclone having a lower portion cone and a ceiling, of which a first upper cyclone (1A) has a first hot gas inlet pipe (2) opening into the ceiling of the first upper cyclone (1A) and a gas outlet pipe (3A), each cyclone having a lower vertical flow line (5A to 5E) of the solid to the ceiling of the adjacent cyclone; the device being characterized in this than :
said first upper cyclone (1A) also comprises a pipe biomass feed (6);
the other cyclones (1B to 1E) each comprise a gas inlet pipe (4B to 4E) and a gas outlet line (3B to 3E); and said gas inlet pipe (4B to 4E) of the other cyclones opens also in the corresponding cyclone ceiling. 2. Device according to claim 1, characterized in that said pipe hot gas supply (2) and said inlet lines (4B to 4E) of the gas are inclined in a last section in the upper part of the cyclone corresponding and flow directed downward. 3. Device according to claim 2, characterized in that said tilt is at least 20 ° from the horizontal. 4. Device according to any one of claims 1 to 3, characterized in what said gas outlet pipe (3B to 3E) is disposed laterally to said part conical cyclone and inclined downward. 5. Device according to any one of claims 1 to 4, characterized in that said biomass feed pipe (6) is a vertical pipe (6) disposed on the axis of symmetry of the first upper cyclone. 6. Device according to any one of claims 1 to 5, characterized in what said plurality of cyclones (1A to 1E) is arranged in a tower, their axes symmetry (X) being aligned. 7. Use of the solid biomass drying device as defined in Moon any of claims 1 to 6 for producing a dried biomass, characterized in that said device is installed in a bed loop fast fluidized comprising a reactor (10), an associated separation cyclone (11) and a return line of the solids (12) of this cyclone to the reactor, said conduct supplying hot gas (2) being fed with gases withdrawn from the outlet said separation cyclone (11). 8. Use according to claim 7, characterized in that the biomass dried in outlet of the drying device is injected into said reactor (10). 9. Use according to claim 7 or 8, characterized in that solids are withdrawn from said return line (12) and mixed with the biomass fed to the drying device.