CA2843997A1

CA2843997A1 - Improved materials

Info

Publication number: CA2843997A1
Application number: CA2843997A
Authority: CA
Inventors: Peter Hammond
Original assignee: CCM Research Ltd
Current assignee: CCM Research Ltd
Priority date: 2014-02-26
Filing date: 2014-02-26
Publication date: 2015-08-26

Abstract

A method of affixing carbon dioxide onto the surface of a material, the method comprising the steps of: (a) contacting a cellulosic material with a composition comprising an amino compound; (b) contacting the cellulosic material with a composition comprising a source of metal ions; and (c) contacting the cellulosic material with a composition comprising carbon dioxide.

Description

Improved Materials The present invention relates to a method for the transportation and/or storage of carbon dioxide.
Due to increased global industrialisation the emissions of carbon dioxide into the atmosphere from the burning of fossil fuels is causing significant environmental changes throughout the world. There exists therefore an urgent need to reduce the level of carbon dioxide in the atmosphere. Whilst reduction of emissions through the use of alternative greener technologies is being used to reduce emissions of carbon dioxide, significant levels are still being released through the burning of fossil fuels. There are various methods by which carbon dioxide produced from the combustion of fossil fuels can be "captured" and stored.
However such methods are often complex and expensive and long term storage solutions are problematic.
Current methods of transporting carbon dioxide long distances include via pipelines or in tankers. However pipelines are difficult and expensive to build and only connect particular points. Tankers such as those used to transport liquefied petroleum gas can also be used.
However gases having a maximum pressure of about 15 bar can typically be transported in this way and thus tankers of this type are not practical for transporting very large quantities of carbon dioxide.
The present invention seeks to provide an improved method by which carbon dioxide, and in some cases sulfur dioxide can be stored and/or transported.
According to a first aspect of the present invention there is provided a method of affixing carbon dioxide onto the surface of a material, the method comprising the steps of:
(a) contacting a cellulosic material with a composition comprising an amino compound;
(b) contacting the cellulosic material with a composition comprising a source of metal ions;
and (c) contacting the cellulosic material with a composition comprising carbon dioxide The method of the present invention involves the treatment of a cellulosic material.
The cellulosic material may be a natural material or it may be a synthetic material, or it may be a semi-synthetic material, for example a natural material processed into a different form.
Suitable materials include a natural cellulosic material or a semi-synthetic, processed, cellulosic material, for example, rayon or lyocell. The cellulosic material may comprise natural =

2 fibres and/or synthetic fibres and/or semi-synthetic fibres, for example regenerated cellulose products. Preferably the material comprises natural fibres.
The use of natural fibres may help improve the environmental profile of the product obtained by the method of the present invention.
Preferably the cellulosic material of the present invention is derived from plant fibres, for example vegetable fibres, or wood fibres.
Suitable natural fibres for use in the method of the present invention include cotton, hemp, flax, silk, jute, kenaf, ramie, sisal, kapok, agave, rattan, soy bean, vine, banana, coir, stalk fibres, wood fibres and mixtures thereof.
The cellulosic material is preferably in the form of small strands or fibres, or in powdered or particulate form. The size and shape of the particles or strands of cellulosic material will depend on the source from which it is derived. For example the cellulosic material may comprise fines from the processing of wood fibres.
In another embodiment the cellulosic material may be derived from the waste products of bioethanol production.
Suitably the cellulosic material is provided in the form of strands or particles having an average size of less than 5 cm, for example less than 3 cm or less than 1 cm. In some emboiments the cellulosic material is provided in the form of strands or particles having an average size of less than 5 mm, preferably less than 1 mm. A typical size may be from 1 to 100 pm, preferably from 5 to 50 pm, preferably from 10 to 20 pm.
Step (a) comprises contacting the cellulosic material with a composition comprising an amino compound. The amino compound may be any compound containing an amino or substituted amino moiety for example ammonia, an aliphatic or aromatic amine, an amide or urea.
Preferably the amino compound is selected from ammonia or an amine. Any suitable amine may be used including aromatic and aliphatic amines. Preferred amines are aliphatic amines for example alkyl amines, alkenyl amines or alkynyl amines. Such amines may be substituted or unsubstituted. Suitable substituted amines include amino acids and alcohol amines (alkanolamines), for example of formula R1R2R3N where R1 is a group of formula HO-X- where X represents a C14 alkylene group, preferably an ethylene group, R2 represents a hydrogen atom or a group of formula HO-X-, and R3 represents a hydrogen atom or a group of formula HO-X- (the groups X being the same or different). Monoalkanolamines and dialkanlamines are preferred, especially ethanolamine (diethanolamine and/or monoethanolomine).

=

3 Especially preferred amines for use herein are alkyl amines, most preferably unsubstituted alkyl amines and alkanolamines.
The amino compound may be ammonia, a primary amine, a secondary amine or a tertiary amine. Preferred amines for use in step (a) of the present invention are primary amines, secondary amines, or mixtures thereof. Especially preferred amines for use herein are primary or secondary alkyl amines, especially alkyl amines having up to 12 carbon atoms, preferably up to 10 carbon atoms, suitably up to 8 carbon atoms, more preferably up to 6 carbon atoms, for example up to 4 carbon atoms. Preferred amines for use herein are methylamine, dimethylanine, ethylamine, diethylamine, propylamine, dipropylamine, butylamine, dibutylamine and mixtures and isomers thereof. In an especially preferred embodiment step (a) comprises contacting the surface of the material with a composition comprising ethylamine, diethylamine or a mixture thereof.
The composition used in step (a) of the method of the present invention may comprise neat concentrated amino compound in gaseous or liquid form or it may comprise one or more further components including, for example, a diluent or carrier. Preferably the composition used in step (a) is a liquid composition. This may be applied by any suitable technique such as will be well known to the person skilled in the art. For example it may be applied by spraying, padding or, immersion. Suitably a solution of amine in a solvent may be applied to the material and then the material dried to effect evaporation of excess solvent and/or amine.
Suitable solvents include water, organic solvents and mixtures thereof. In some embodiments the composition used in step (a) comprises an amino compound provided as a vapour.
Suitably in such embodiments the material is placed in a sealed vessel and the amino compound vapour is then passed through the vessel.
In preferred embodiments step (a) comprises contacting the cellulosic material with a composition comprising at least 10 wt% amino compound, preferably at least 20 wt% amino compound, suitably at least 40 wt%, at least 60 wt% or at least 70 wt%.
Suitably step (a) comprises applying a composition comprising up to 100 wt% amino compound, for example up to 95 wt% or at least 90 wt%.
In preferred embodiments step (a) comprises contacting the cellulosic material with a composition comprising from 10 to 40 wt% amino compound.
Preferably the composition containing an amino compound contains at least 5 wt% water, preferably at least 10 wt% water, for example about 20 wt% water. In some embodiments the composition may comprise up to 50 wt% water.

4 Some preferred compositions for use in step (a) consist essentially of water and the amino compound. The amino compound is preferably in an amount as defined above and the water is the balance of the composition.
The skilled person will however appreciate that commercially available amines often contain mixtures and/or impurities.
In some preferred embodiments the composition comprises the amino compound as a neat liquid.
However, the presence of water in the composition containing the amino compound is believed to be beneficial and is preferred.
Step (a) may be carried out at any suitable temperature and pressure. Suitable temperatures include from 0 to 80 C, for example from 5 to 60 C, suitably from 10 to 40 C, for example from 15 to 35 C. Suitably in step (a) the material is contacted with a composition comprising an amino compound at room temperature. Step (a) may be carried out under high pressure.
However in preferred embodiments step (a) involves contacting the material with an amino compound under standard atmospheric pressure.
Preferably the contact time of the cellulosic material with the composition comprising the amino compound is from 0.1 to 500 minutes, preferably from 1 to 200 minutes, for example from 2 to minutes, suitably from 5 to 60 minutes.,preferably from 10 to 40 minutes.
Suitably in step (a) of the method of the present invention an interaction occurs between the surface of the cellulosic material and the amino compound. Any type of interaction may occur and depends on the particular amino compound. The surface of the material and the amino compound are believed to interact in a way which (though not at present fully understood) appears to promote the take-up of carbon dioxide in step (c).
Without being bound by theory, it is believed that hydrogen bonding occurs between the amino functionality and the surface of the cellulosic material.
The uptake of the amino compound by the cellulosic material is suitably at least 5% omf, preferably at least 10% omf, more preferably at least 15% omf, for example at least 20 A omf.
The uptake of the amino compound on the cellulosic material may be up to 100%
omf, preferably up to 80% omf, more preferably up to 70% omf, for example up to 60%
omf.

By % omf (% on mass of fibre) we mean to refer to the mass of amino compound as a percentage of the mass of the fibres treated.
Step (b) of the method of the first aspect of the present involves contacting the cellulosic

5 material with a source of metal ions.
Suitable metal ions include any monovalent, divalent and trivalent ions, especially those having low toxicity.
Preferred metal ions include alkali metal ions and alkaline earth metal ions.
Especially preferred are alkali metal ions. Most preferred are sodium ions.
The metal ions are preferably provided in aqueous solution. They may be provided in the form of a salt.
Preferably the source of metal ions is an alkali metal hydroxide solution.
Most preferably it is a solution of sodium hydroxide.
Suitably in step (b) the cellulosic material is contacted with a composition comprising at least 5 wt% of an alkali metal hydroxide, preferably at least 10 wt%, more preferably at least 15 wt%, for example at least 20 wt% or at least 25 wt%.
Suitably in step (b) the cellulosic material is contacted with a composition comprising up to 60 wt% of an alkali metal hydroxide, preferably up to 50 wt%, more preferably up to 40 .wt%, for example up to 35 wt%.
Step (b) may be carried out before step (a), after step (a), or at the same time as step (b).
In some embodiments steps (a) and (b) are carried out simultaneously. Step (a) may therefore comprise contacting the cellulosic material with a composition comprising an amino compound and a source of metal ions. Such a composition may be prepared by admixing an aqueous composition comprising 10 to 50 wt%, preferably 20 to 40 wt% of an alkali metal hydroxide with a composition comprising 50 to 10 wt%, preferably 70 to 90 wt% of an amino compound.
In such embodiments the cellulosic fibres may optionally be contacted with a further source of metal ions in a subsequent step.
Preferably step (b) is carried out after step (a).

=

6 Preferably step (b) is carried out at a temperature of from 0 to 100 C, suitably from 0 to 80 C, for example from 10 to 50 C. Suitably step (b) is carried out at ambient pressure. Preferably in step (b) the cellulosic material is contacted with a composition comprising a source of metal ions for a period of between 0.1 and 500 minutes, preferably between 1 and 200 minutes, more preferably between 2 and 100 minutes, suitably between 5 and 60 minutes, for example between 10 and 40 minutes.
The uptake of metal ions in step (b) is preferably at least 1% omf, preferably at least 5% omf, suitably at least 10% omf.
The uptake of metal ions on the cellulosic fibre may be up to 100% omf, suitably up to 75%
omf, for example up to 50% omf or up to 30% omf.
In some embodiments the material obtained following step (b) may be dried prior to step (c).
Suitable drying conditions will be known to the person skilled in the art.
Step (c) of the method of the present invention involves contacting the cellulosic material with a composition comprising carbon dioxide.
Steps (c) of the present invention may be carried out at the same time as steps (a) and (b), when these two steps are carried out together. However in preferred embodiments step (c) is carried out after step (a) and step (b) and thus step (c) preferably comprises contacting the surface of a cellulosic material which has been contacted with an amino compound and a source of metal ions with a composition comprising carbon dioxide. Thus step (b) suitably involves contacting a cellulosic material carrying an amino compound and a metal ion with a composition comprising carbon dioxide.
In the composition used in step (c) the carbon dioxide may be provided as carbon dioxide gas, as supercritical carbon dioxide or as solid carbon dioxide. In preferred embodiments the carbon dioxide is in gaseous form.
In some embodiments the composition contacted with the material in step (c) may also comprise sulfur dioxide.
When the composition used in step (c) comprises sulfur dioxide this is preferably provided in gaseous form.
In preferred embodiments the gas used in step (c) is provided by a gaseous composition comprising at least 1 wt% carbon dioxide. Preferably composition contacted with the cellulosic

7 material in step (c) is a gaseous composition comprising at least 5 wt% carbon dioxide, preferably at least 10 wt% carbon dioxide, preferably at least 20 wt% carbon dioxide. In some embodiments step (c) involves treating the cellulosic fibres with a composition comprising at least 50 wt% carbon dioxide, for example at least 75 wt%, at least 90 wt% or at least 95 wt%.
Preferably the composition contacted with the cellulosic material in step (c) of the method of the present invention comprises carbon dioxide. In some embodiments the composition used in step (c) consists essentially of carbon dioxide.
In some embodiments the composition contacted with the cellulosic material comprises sulfur dioxide.
In some preferred embodiments the composition comprises a mixture of carbon dioxide and sulfur dioxide. It may comprise other components, suitably other gaseous components, for example nitrogen.
In some preferred embodiments the composition contacted with the cellulosic material in step (c) comprises or is derived from the exhaust gas of a combustion system. For example the composition may comprise the flue gases of a power station, for example a wood-burning or coal-burning power station.
In some embodiments such exhaust gases may be concentrated or otherwise treated prior to contact with the fibres of cellulosic material.
In especially preferred embodiments the carbon dioxide and/or sulfur dioxide is provided by the exhaust of a fossil fuel burning engine, boiler, furnace or turbine. Thus the present invention may involve a method of capturing carbon from the atmosphere.
The composition used in step (c) may comprise at least 0.1 wt% sulfur dioxide, preferably at least 0.5 wt%, for example at least 1 wt%. It may comprise up to 20 wt% sulfur dioxide, for example up to 10 wt% or up to 7 wt%.
In one embodiment the composition contacted with the cellulosic material is a gaseous composition comprising from 50 to 90 wt%, preferably 60 to 80 wt% nitrogen, from 10 to 40 wt%, preferably 20 to 30 wt% carbon dioxide and up to 20 wt%, preferably up to 10 wt% sulfur dioxide.

=

8 In some embodiments in step (c) a gaseous composition may be pumped into a vessel containing the material. In some embodiments the cellulosic material may have been dried following steps (a) and (b). Alternatively the material may still be damp.
Step (c) may be carried out at atmospheric pressure or it may be carried out at higher pressures. The skilled person will appreciate that when elevated pressures are used the contact times needed are generally shorter than when lower pressures are used.
In some embodiments the composition contacted with the material in step (c) may comprise carbon dioxide, sulfur dioxide or a mixture thereof along with a diluent or carrier. In some embodiments the composition may comprise only carbon dioxide, sulfur dioxide or a mixture thereof.
In some preferred embodiments the composition contacted with the material in step (c) consists essentially of carbon dioxide, i.e. it is provided from a source of carbon dioxide without the addition of a diluent or carrier. Minor impurities may be present.
In embodiments in which the cellulosic material is contacted with neat carbon dioxide gas this may be provided at a pressure of up to 40,000kPa, preferably from 100 to 5000 kPa. In some embodiments carbon dioxide may be delivered to the cellulosic material at ambient pressure, and preferably at ambient temperature. In preferred embodiments the carbon dioxide gas is at a supra-atmospheric pressure. In one embodiment a pressure of from 2000 to 4000 kPa, for example about 3000 kPa is used.
Preferably in step (c) the cellulosic material is contacted with the composition comprising carbon dioxide for a period of 0.1 to 500 minutes, preferably to 200 minutes, more preferably to 100 minutes, suitably 5 to 60 minutes, for example 10 to 40 minutes.
The uptake of carbon dioxide on the cellulosic material is preferably at least 1% omf, preferably at least 5% omf, more preferably at leas 10% omf, for example at least 15% omf.
The uptake of carbon dioxide on the cellulosic material may be up to 100% omf, suitably up to 80% omf, preferably up to 60% omf, for example up to 50% omf or up to 40% omf.
For the avoidance of doubt, the above amounts refer to the increase in weight of the treated cellulosic material, i.e. material that carries an amine and metal ions on the surface thereof.
It is an advantage of the present invention that relatively short contact times can be used in steps (a), (b) and (c) to achieve sufficient retention of carbon dioxide and optionally sulfur =

9 dioxide on the surface of the cellulosic material. For example contact times of less than 1 hour, preferably less than 30 minutes can be used, in each of steps (a), (b) and (c).
Without wishing to be bound by theory it is believed that the carbon dioxide or sulfur dioxide interacts with the amino compound which is carried by the surface of the cellulosic fibres following step (a). The nature of this interaction is not fully understood. It is believed that there may be a polar interaction, a hydrogen bond may form, or covalent bonding may occur.
Following step (c) the method may provide a cellulosic material in which carbon dioxide, and optionally sulfur dioxide, are retained on the surface.
By retained on the surface it is meant that the carbon dioxide and sulfur dioxide when present is not labile, i.e. the molecules of carbon dioxide (and optionally sulfur dioxide) are not merely associated with the surface and simply present in the same general area.
Rather they are fixed at the surface. They may be permanently or temporary fixed at the surface. Suitably the molecules of carbon dioxide and when present sulfur dioxide are not readily displaced from the surface of the cellulosic material without the application of an external stimulus.
The carbon dioxide and when present sulfur dioxide may be retained on the surface may physical and/or by chemical means. For example the carbon dioxide and/or sulfur dioxide may be retained by Van der Waals forces, hydrogen bonding or ionic forces.
Preferably the carbon dioxide and/or sulfur dioxide is retained on the surface by means of a chemical bond, suitably a covalent bond.
Following step (c) the carbon dioxide may be permanently retained or bonded or it may be retained in a manner such that it could be released later. Hence the carbon dioxide and, when present, sulfur dioxide may be fixed to the surface of the material in a reversible or irreversible manner.
In some especially preferred embodiments the carbon dioxide and, when present sulfur dioxide, retained on the surface is not readily released from the material under normal storage and transport conditions. Thus the treated cellulosic material is preferably stable at all humidities, at standard atmosphere pressure and at temperatures of between -30 C and 70 C, for example between -20 C and 60 C, between -10 C and 50 C, or between 0 C and 40 C.
The treated cellulosic material is suitably weatherproof and carbon dioxide is not released under normal climatic extremes of heat or cold or in very wet, very dry, windy or stormy environments.

=
Following step (c) the material may be dried. Suitable drying conditions will be known to the person skilled in the art.
In some embodiments the method of the first aspect of the present invention may include a =
5 further step (d) of forming the material obtained following step (c).
Suitable forming steps will be known to the person skilled in the art. In one embodiment the material is formed into pellets to facilitate transport and improve bulk density.
According to a second aspect of the present invention there is provided a cellulosic material

10 which has been treated with an amino compound and a source of metal ions and which has carbon dioxide retained on the surface thereof.
The material of the second aspect is preferably prepared by the method of the first aspect.
Preferred features of the second aspect are as defined in relation to the first aspect.
The material of the second aspect is a material on the surface of which carbon dioxide is retained. Thus this material may be used as a means for storing and/or transporting carbon dioxide. In some embodiments sulfur dioxide may also be retained on the surface of the material.
Preferably the material of the second aspect comprises at least 5 wt% carbon dioxide, preferably at least 10 wt%, more preferably at least 15 wt%, for example at least 20 wt%.
The material of the second aspect may comprise up to 50 wt% carbon dioxide, for example up , to 40 wt%.
The material of the present invention is preferably stable at temperatures of up to 50 C and thus can be easily transported large distances, for example in container ships.
The material of the second aspect may find utility in subsequent applications, for example it could be used as a fertiliser, as a strengthening aid in plastics or as a filler in building materials.
In some embodiments the material may be prepared at or delivered to a location suitable for long term storage, to avoid releasing the carbon dioxide into the atmosphere.
Suitable long term storage locations preferably are not subjected to extremes of heat or pressure.
However in preferred embodiments the material will be used directly in another application or will be coverted into or incorporated in a useful product.

11 There may be instances in which it is desired to release carbon dioxide from the surface of the material, for example after a period of storage or following transport to a particular location.
Release of carbon dioxide may be achieved by application of an external stimulus, for example by heating the material, contacting the material with a chemical reagent or application of a mechanical force.
Thus the present invention may enable waste carbon dioxide from a first location to be captured, stored and transported to a second location where it can be released and used as appropriate.
The inventors have found that when using cellulosic material that has been contacted with a source of metal ions as well as an amino compound the carbon dioxide is more strongly retained on the surface than when only an amino compound is used, for example the treated material has been found to be more stable to an increase in temperature.
In embodiments in which long term storage of the carbon dioxide is desired a higher ratio of metal ions to amino compound is preferably used (i.e. an excess of metal ions).
If it is intended that the carbon dioxide is to be released from the material following transportation it is preferable to use a lower ratio of metal ions to amino compound (i.e. an excess of amino compound).
The material of the second aspect is a solid material based on organic matter and which comprises up to 50 wt%, typically 10 to 35 wt% carbon dioxide. This material is a solid and is stable under most normal atmospheric conditions. It can therefore be transported by any suitable means, in standard containers. It can be shipped and transported by road or rail in standard bulk containers which do not need to be adapted or handled in any particular way. No special precautions are necessary. Thus the material can be transported cheaply and easily from one location to another with no restrictions. This offers significant advantages over the prior art.
The invention will now be further defined with reference to the following non-limiting examples.
Example 1 kg of wheat based bioethenol waste was mixed with 500m1 of a composition comprising monoethanolamine and 20 wt% water in a tumble mixer for 10 minutes at standard

12 temperature and pressure. This mixture was then passed into a screw mixer through which pure CO2 at a pressure of 5 bar was passed. The material was contacted with the the CO2 in the screw mixer for 5 mins at stp. After 5 mins 200m1 of 50 wt% aqueous NaOH
was added to the screw mixer with CO2 being continuously fed into the system for an additional 5 minutes.
After the 5 minutes has elapsed the screw mixer was emptied via a cooled (<50 C) pelletising dye. This material obtained is sufficiently stable for onward transportation.

Claims

1. A method of affixing carbon dioxide onto the surface of a material, the method comprising the steps of:
(a) contacting a cellulosic material with a composition comprising an amino compound;
(b) contacting the cellulosic material with a composition comprising a source of metal ions; and (c) contacting the cellulosic material with a composition comprising carbon dioxide.

2. A method as claimed in claim 1 wherein the cellulosic material is a fibrous material

3. A method as claimed in claim 2 wherein the cellulosic material comprises natural fibres.

4. A method as claimed in claim 3 wherein the cellulosic material is derived from plant fibres.

5. A method as claimed in any proceeding claim wherein the amino compound comprises ammonia or an amine.

6. A method as claimed in any proceeding claim where in the amino compound is provided in a solvent, preferably water.

7. A method as claimed in any proceeding claim wherein step (a) is carried out at temperature in the range from 0 to 80°C and with a contact time, of the cellulosic material with the composition comprising the amino compound, of from 0.1 to minutes.

8. A method as claimed in any proceeding claim wherein the source of metal ions includes alkali metal ions and alkaline earth metal ions.

9. A method as claimed in any proceeding claim wherein the composition contacted with the cellulosic material in step (c) comprises or is derived from the exhaust gas of a combustion system.

10. A method as claimed in any proceeding claim wherein the uptake of carbon dioxide on the cellulosic material is preferable at least 1% omf.

11. A method as claimed in claim 10 wherein molecules of carbon dioxide are fixed on the surface of the cellulosic material.

12. A cellulosic material which has been treated with an amino compound and a source of metal ions and which has carbon dioxide retained on the surface thereof.

13. A cellulosic material as claimed in claim 12 wherein the material comprises at least 5 wt% carbon dioxide and is stable at temperatures of up to 50°C.