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Title:
PROCESS AND RELATED SYSTEM FOR REMOVING ASHES FROM BIOMASSES
Document Type and Number:
WIPO Patent Application WO/2017/208268
Kind Code:
A1
Abstract:
A process is described for removing ashes from biomasses, through a system (1) comprising mixing means (10) and (20), filtering means (30) and distilling means (40) and at least one storage system (50) to allow separating and removing ashes from biomasses, comprising the following steps: depolymerizing organic material present in the biomass and separating the organic material, depolymerized and dissolved in the solvent, with respect to a solid ash-rich residue; filtering the organic material, depolymerized and dissolved in the solvent; distilling and regenerating the solvent present in an environment with high temperature; and extracting and storing biomass without ashes. A system (1) for removing ashes from biomasses is further described.

Inventors:
FAUSSONE GIAN CLAUDIO (IT)
GRILC MIHA (SL)
LIKOZAR BLAZ (SL)
Application Number:
PCT/IT2016/000140
Publication Date:
December 07, 2017
Filing Date:
May 30, 2016
Export Citation:
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Assignee:
INSER ENERGIA S P A (IT)
KEMIJSKI INST LJUBLJANA (SI)
International Classes:
C10G31/09; C10G1/00; C10G1/02; C10G1/08
Domestic Patent References:
WO2016058031A12016-04-21
WO2016150965A12016-09-29
Foreign References:
EP2891748A12015-07-08
KR20090016392A2009-02-13
US20120009660A12012-01-12
US20120009660A12012-01-12
Attorney, Agent or Firm:
GARAVELLI, Paolo (IT)
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Claims:
CLAIMS

1. Process for removing ashes from biomasses through a system (1) comprising mixing means (10) and (20) , filtering means (30) and distilling means (40) and at least one storage system (50) to allow separating and removing ashes from biomasses, characterized in that it comprises the following steps :

a) through said mixing means (10), depolymerizing organic material present in the biomass, to allow converting the organic material into a soluble state by means of a solvent, and separating the organic material, depolymerized and dissolved in the solvent, with respect to a solid residue, rich of ashes, of inorganic substances and possibly of residues of not depolymerized organic material;

b) through said filtering means (30), filtering the organic material, depolymerized and dissolved in the solvent;

c) through said mixing means (20) and said distilling means (40) , distilling and regenerating the solvent present in an environment with high temperature; and

d) through said storage system (50), extracting and storing biomass without ashes.

2. Process for removing ashes from biomasses according to the previous claim, characterized in that the step of depolymerizing the organic material present in the biomass occurs at a reaction temperature included between 150 °C and 250°C, by melting in at least one solvent, of the methanol, ethanol, isopropyl alcohol, diethylene glycole, ethylene glycole, glycerol and water type, in combination with a homogeneous catalyst to allow accelerating the melting of the organic material.

3. Process for removing ashes from biomasses according to any one of the previous claims, characterized in that the step of filtering the organic material, depolymerized and dissolved in the solvent, occurs downstream of an environment with high autogenous pressure to be able to increase the filtering efficiency induced by autogenous pressure.

4. Process for removing ashes from biomasses according to any one of the previous claims, characterized in that the step of distilling and the regenerating the solvent occurs by vaporizing the solvent in an overheated environment.

5. System (1) for removing ashes from biomasses adapted to implement a process for removing ashes from biomasses according to any one of the previous claims, characterized in that said mixing means (10) comprise at least one continuous reactor with stirred tank adapted to allow controlling the melting degree in solvent of the organic material present in the biomass, to generate an autogenous pressure enough to allow keeping at liquid state the majority of volatile solvent.

6. System (1) for removing ashes from biomasses according to the previous claim, characterized in that said mixing means (20) comprise at least one continuous reactor with stirred tank adapted to contain the biomass without ashes, said mixing means (10) and (20) being connected by said filtering means (30), through an inlet valve (31) and an outlet valve (32) .

7. System (1) for removing ashes from biomasses according to the previous claim, characterized in that said filtering means (30) comprise porous means (33) adapted to keep big-sized particles of ashes due to the passage of organic material present in the biomass and of solvent pushed by the autogenous pressure of the continuous reactor with stirred tank of said mixing means (10), said porous means (33) allowing to remove the ashes for following processing and disposing actions.

8. System (1) for removing ashes from biomasses according to claim 6, characterized in that said continuous reactor with stirred tank of said mixing means (20) containing the solvent without ashes, hot filtered at high pressure, comprises at least one heat exchanger (21) to integrate the necessary heat to allow the differential distillation of the solvent through said distilling means (40) , reducing the pressure through a valve (22) .

9. System (1) for removing ashes from biomasses according to the previous claim, characterized in that said distilling means (40) comprise at least one condenser (41) cooled with water at ambient pressure, and collecting means (42) for re-using the solvent.

10. System (1) for removing ashes from biomasses according to claim 5 or 6, characterized in that the continuous reactor with stirred tank belonging to said mixing means (10) and (20) comprises at least one stirrer (13, 23) moved by at least one external motor (14, 24), through a magnetic coupling to guarantee a perfect seal, said stirrer (13, 23) being adapted to make a mass and thermal distribution uniform and to reach a desired melting degree in solvent of the organic material present in the biomass.

Description:
PROCESS AND RELATED SYSTEM FOR REMOVING ASHES FROM BIOMASSES

The present invention refers to a process and a related system for removing ashes from biomasses.

In general, the present invention refers to a reactor for the thermal-chemical conversion of biomass having a high content of ashes to obtain a fuel without ashes.

In particular, the present invention refers to a reactor for the thermal-chemical conversion of biomass, wherein there is a step of removing ashes at liquid state with a solvent by using mixing means, for example stirrers.

Biomass with a high content of ashes used as fuel can imply serious problems, due to the presence of inorganic substances with low melting point and with high particulate emissions.

For this reason, the trend is placing a limit to the acceptable content of ashes present in the fuels. For example, the acceptable content of ashes from wooden pellets is 0.5%, while the one from dry cortex, rice husks and depuration sludges is respectively equal to 5%, 20% and 35% of the inorganic content. On the other hand, composites with a low content of ashes, which are widely available, often cannot have a correct end use.

Methods are known which are based on the removal of ash-rich biomass, before starting a process for pre-treating the biomass.

The prior art is given, for example, by patent application US20120009660A1, which discloses a process for reducing the content of ashes of raw materials from biomasses or a fraction of biomass. Such process comprises the steps of:

adding alcohol and acid to the fraction of biomass for producing a reaction mixture;

separating the reaction mixture into a solid fraction and into a liquid fraction through centrifugation;

distilling the liquid; and

- collecting the solid to recover the reaction reagents .

Patent application US20120009660A1 however has the following limitations:

among the raw materials to be treated, sludges are not mentioned; the maximum process temperature is 90°C;

to recover the solvents, a distilling apparatus is used, which lacks an auxiliary thrust ;

- a humidification step is necessary, before the solvolysis ;

several filtering / stirring / separating passages must fundamentally be used to be able to recover lipids from micro-weeds;

- the maximum ash percentage which it is possible to remove is scarce;

the speed profile of the stirrer is complicated and optimum values for the stirring speed are missing.

Therefore, object of the present invention is solving the above prior art problems, by providing a process for removing ashes from biomasses and a related system to allow separating and removing ashes from biomasses.

A further object is providing a process for converting ash-rich solid biomasses into a liquid or solid fuel, which is without ash, and into an inorganic solid residue, which is rich of ash.

The above and other objects and advantages of the invention, as will result from the following description, are obtained with a process for removing ashes from biomasses as claimed in claim 1. Moreover, the above and other objects and advantages of the invention, as will result from the following description, are obtained with a system for removing ashes from biomasses as claimed in claim 5.

Preferred embodiments and non-trivial variations of the present invention are the subject matter of the dependent claims.

It is intended that all enclosed claims are an integral part of the present description.

It will be immediately obvious that numerous variations and modifications (for example related to shape, sizes, arrangements and parts with equivalent functionalities) could be made to what is described, without departing from the scope of the invention as appears from the enclosed claims.

The present invention will be better described by some preferred embodiments thereof, provided as a non-limiting example, with reference to the enclosed drawing, in which its single Figure 1 shows the diagram of a system and of an embodiment of the process for removing ashes from biomasses according to the present invention. With reference to Figure 1, it is possible to note that a process for removing ashes from biomasses is implemented through a system 1 comprising mixing means 10 and 20, filtering means 30 and distilling means 40, and at least one storage system 50 to allow separating and removing ashes from biomasses.

Advantageously, the process for removing ashes from biomasses comprises the following steps:

a) through the mixing means 10, depolymerizing organic material present in the biomass, to allow converting the organic material into a soluble state by means of a solvent, and separating the organic material, depolymerized and dissolved in the solvent, with respect to a solid residue, rich of ashes, of inorganic substances and possibly of residues of not depolymerized organic material;

b) through the filtering means 30, filtering the organic material, depolymerized and dissolved in the solvent;

c) through the mixing means 20 and the distilling means 40, distilling and regenerating the solvent present in an environment with high temperature; and

d) through the storage system 50, extracting and storing biomass without ashes.

In particular, the step of depolymerizing the organic material present in the biomass occurs at a reaction temperature included between 150 °C and 250°C, by melting in at least one solvent, of the methanol, ethanol, isopropyl alcohol, diethylene glycole, ethylene glycole, glycerol and water type, in combination with a homogeneous catalyst to allow accelerating the melting of the organic material.

The step of filtering the organic material, depolymerized and dissolved in the solvent, occurs downstream of an environment with high autogenous pressure to be able to increase the filtering efficiency induced by autogenous pressure.

The step of distilling and regenerating the solvent occurs through vaporizing the solvent in an overheated environment.

Such process is adapted to be performed through a system 1 for removing ashes from biomasses, wherein the mixing means 10 comprise at least one continuous reactor with stirred tank suitable to allow controlling the melting degree in a solvent of the organic material present in the biomass, in order to generate an autogenous pressure which is enough to allow keeping at liquid state the majority of the volatile solvent.

In particular, the mixing means 20 comprise at least one continuous reactor with stirred tank adapted to contain the biomass without ashes.

The mixing means 10 and 20 are connected by the filtering means 30, through an inlet valve 31 and an outlet valve 32.

The filtering means 30 comprise porous means 33 suitable to keep big-sized particles of ashes due to the passage of organic material present in the biomass and of solvent pushed by the autogenous pressure of the continuous reactor with stirred tank of the mixing means 10. In particular, the porous means 33 allow removing the ashes for following processing and disposing actions.

The continuous reactor with stirred tank of the mixing means 20 contains the solvent without ashes, hot filtered, at high pressure. Such reactor comprises at least one heat exchanger 21 to integrate the necessary heat to allow the differential distillation of the solvent through the distilling means 40 by reducing the pressure through a valve 22.

The distilling means 40 comprise at least one condenser 41, water cooled at ambient pressure, and collecting means 42 for re-using the solvent.

From a construction point of view, such continuous reactor with stirred tank belonging to the mixing means 10 and 20 comprises at least one stirrer 13, 23 moved by at least one external motor 14, 24, through a magnetic coupling to guarantee a perfect seal. The stirrer 13, 23 allows making mass and thermal distributions uniform, and reaching the desired melting degree in a solvent of the organic material present in the biomass.

The process and the related system for removing ashes from biomasses according to the present invention allow reaching the stated obj ects .

In particular, the first step of the process for removing ashes from biomasses of the present invention occurs in a continuous reactor with stirred tank, namely a chemical, Continuous-Flow Stirred-Tank Reactor (CFTR) , and implies the conversion of organic components from ash-rich biomasses into their solvent-soluble state, while inorganic components remain at solid state dispersed in a liquid paste. In the second step, the liquid phase is separated as suspension from the solid phase and filtered in the filtering means comprising a filter for high temperatures. The liquid mass, filtered and without ashes, enters into a second continuous reactor with stirred tank, in which the solvent is distilled and recovered, while the depolymerized biomass remains on the bottom of the reactor.

In detail, a first step provides for the melting of organic components in a single solvent or mixture of solvents, including but not limited to methanol, ethanol, isopropyl alcohol, diethylene glycole, ethylene glycole, glycerol and water. The melting rate can be accelerated with the addition of a homogeneous catalyst. Melting of organic components from ash-rich biomasses occurs discontinuously in a first continuous reactor with stirred tank, a reaction temperature included between 150 and 250 °C and at the autogenous pressure which keeps the majority of the volatile solvent at its liquid state. The reactor contents is stirred through a stirrer with magnetic coupling with perfect seal containing one or more impellers to keep the reactor homogeneous in terms of dispersion of particles and of temperature. Once having reached the desired melting degree, the first step is complete and the reaction mixture is ready for its following filtering.

A second step provides for the physical separation of depolymerized organic material dissolved in a solvent, with respect to an ash-rich solid residue which mainly contains inorganic raw material, and possibly some non-converted organic components. Filtering occurs with open admitting valves of the filtering means, allowing the hot reaction mixture to be pressed through the filter by means of autogenous pressure. Solid particles with bigger size with respect to filter pores are kept, while filtered material without ashes enters into the second continuous reactor with stirred tank. The ash-rich filter is recovered to be further processed or disposed of.

A third step of the process of the invention provides for the regeneration of solvent from hot and pressurized filtered material without ashes for differential distillation, in such second continuous reactor with stirred tank. Heat of the liquid reaction mixture, at high pressure, at a temperature much greater than the boiling point at ambient pressure, is exploited for vaporizing the solvent, reducing the pressure by opening a valve. Possible further heat necessary for recovering the solvent is provided by the heat exchanger 21. The solvent vapors condense in a water-cooled condenser at ambient pressure and are collected to re-use them. The depolymerized biomass without ashes is a product of the process and remains in the second continuous reactor with stirred tank to be collected from its bottom.

Such process product can be solid, pasty or liquid according to the nature of the biomass and to the content of possibly unrecovered solvent.