FI20185748A1 - Porous, formable material and method for manufacturing the same - Google Patents

Abstract

The invention relates to a porous molding material and a method for producing the same. The process uses a lignocellulosic starting material to form a lignin-containing mixture from the fractions from biomass fractionation, which is treated to produce a porous body. In the method, the material is foamed, shaped, heat treated, carbonized and activated. The available charred and activated part is suitable for e.g. filler, filter and catalyst filler.

Description

PORRY MOLDING MATERIAL AND METHOD FOR ITS MANUFACTURE

Engineering

The present invention relates to porous moldable biomaterial-based materials, their preparation and their use.

In particular, the invention relates to a method according to the preamble of claim 1 for obtaining a porous shaped body and to a product obtainable by such a method.

The invention also relates to a porous body according to claim 16 and to its use.

State of the art

So-called porous carbon is found to be used in many different applications, such as thermal insulation (even at very high temperatures), various filters and catalysis. In catalytic reactions, porous carbonized materials are used in particular as catalyst supports due to their high specific surface area.

Traditionally, porous carbon materials are mainly made by carbonizing synthetic resin foams such as polyurethane and phenolic resin foams. Such materials are non-ecological and expensive to manufacture. Thus, research seeks to find alternative materials for these synthetics. It is known e.g. use of lignin to replace phenols in polyurethane foam.

In the past, efforts have been made to produce various bio-based foam products based mainly on pure biomaterial-based starting materials, such as tannin, lignin and furfural alcohol, but the use of impure starting materials has also been studied.

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The prior art in this respect is represented, for example, by US3894848, which discloses the preparation of a porous molding material from an aqueous solution of lignin. The process comprises foaming the starting material and. heat treatment in a mold as well as carbonization of the porous material thus obtained.

The articles “Tannin based foams and its derived carbon foams” (Tondi, G. et al, 2010) and “Chemistry, morphology, micro tomography and activation of natural and carbonized tannin foams for different applications” (Pizzi, A., 2012) have described 95% pure tannin foams and their carbonization and possible activation.

WO2005016818 describes a process for preparing a carbon foam from a metal salt of a lignosulfonate. In the process, flotation and carbonization of the starting material are performed simultaneously in an oxygen-free atmosphere, at pressures above 100 psi and at temperatures above 250 ° C.

It is also known to make activated carbon from carbon materials, the operation of which is based on adsorption, in which case the activated carbon acts as an adsorbent, binding to its surface certain molecules from either a gaseous or a liquid substance. Typically, in the pores of the foamed carbon material 20, depending, of course, on the pore size and the size of the molecules, the molecules are trapped solely because of their physical size, whereby the porous material already functions as such. sihtinä. A significant feature of activated carbon is its particularly porous structure, which provides its high specific surface area and at the same time improves the filterable properties of activated carbon.

The size of the effective surface area of activated carbon varies greatly depending on the degree of activation of the carbon and the raw material used to make the activated carbon. The aim is to choose a material that gives the best properties of activated carbon for future use. The most commonly used activated carbon raw materials are wood, sawdust, peat, 30 coconut shells, coal and crude oil waste. Typically, the selected feedstock is crushed and then carbonized at a temperature of about 800-1000 ° C. During charring most. hydrocarbon and part. the carbon is removed, leaving the surface area of the carbon. grow.

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Activation of carbon can improve the adsorption capacity of carbon organic matter by increasing the pore collector diameter. During the activation, various substances are removed from the carbon pores, leaving empty spaces in the structure, i.e. the volume of the pores increases. The substances removed as a result of the activation also form completely new pores in the carbon. The specific surface area of activated carbon is typically 500-1500 m7g.

When choosing a raw material, it is important to take into account the desired particle size of the final product, the structure of the pores, the total surface area and the empty space between the ingredients, and of course the price of the raw material.

Typically, the activated carbon is either in a fine powder or in granular form, but foamed activated carbon has also been prepared.

It is also known to produce activated carbon from biomass. Such have been described e.g. in CN1070021486 and US4552863. CN1070021486 discloses a process for producing activated carbon from biomass by foaming, calcining and finally activating the carbonized foam using a gas. In the process of US4552863, activated carbon is produced using wood as a carbon source.

Heat-treated foams alone have often been found to be quite brittle. In addition to other properties, carbonization or activation also improves the mechanical resistance of the porous material.

Furthermore, there is room for improvement in the properties of porous materials, and in particular in formability and in the starting materials used. In particular, the use of ecological feedstocks must be made more efficient and the utilization of industrial by-products must be further increased. Nor has any starting material succeeded in optimizing all the advantageous properties simultaneously with environmental friendliness and affordability.

The desired properties are relatively low density, mechanical strength, and high thermal conductivity, which is usually the result of at least a partially organized crystal structure.

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General description of the invention

It is an object of the present invention to provide a novel method for producing porous moldable materials from organic starting materials. In particular, it is an object to provide a process for the preparation of carbon foams using low-cost starting materials which, however, have the necessary physical and chemical properties for use.

In particular, it is an object of the invention to provide a process for preparing carbon foams from a lignocellulosic starting material.

It is also an object of the invention to provide a novel mouldable material.

The invention is based on the finding that by treating the lignocellulosic starting material with the process according to the invention, a bioavoidable porous shaped body can be formed which is carbonized throughout and. enabled.

In the process according to the invention, the mixture containing a liquid medium is formed from a lignin-containing fraction obtained from a biomass fractionation furnace, to which other fractions formed as a result of the biomass fractionation are optionally added.

The formed mixture is foamed and shaped in a mold to a predetermined shape. The shaped foam thus obtained is further subjected to a heat treatment, after which it is carbonized and finally activated.

As shown, foamed biomass-based bodies are provided which can be used, for example, in various cleaning applications, such as the cleaning or purification of gases and liquids, as a filler or as a catalyst filler.

More specifically, the invention is characterized by what is set forth in the characterizing parts of the independent claims.

The invention provides considerable advantages. Thus, the method achieves

20185748 prh 07-09- 2018 self-supporting monolithic, activated, porous structures. In particular, porous shaped bodies are obtained which are carbonized and activated throughout. The carbonized and activated porous body of the invention has advantageous properties such as low electrical conductivity, low thermal conductivity and low density. These features can also be customized in a variety of ways. In the case of insulators, for example, poor thermal conductivity can be sought by reducing the density, and the electrical conductivity can be adjusted, for example, by adding metals to the foam that conduct electricity better. Electrical conductivity is also affected by, for example, the temperature used in the heat treatment, heat treatment at high temperatures typically improves the electrical conductivity. Thus, the shaped body according to the invention has a wide range of applications.

Most preferably, the flotation according to the invention takes place at normal pressure and at room temperature. However, flotation can also be carried out under reduced or overpressure, for example at 0.1-10 harm absolute pressure. When the mixture is foamed without external heating, the foaming can be better controlled and uniform foam bodies are obtained.

A wide variety of lignocellulosic feedstocks can be used as a starting material in the invention, such as various plants and parts thereof, by-products of various fractionation processes, as well as digestate from peat and biogas plants and other partially biodegraded or treated materials. The bio-based raw materials used in the invention reduce the need for fossil raw materials and reduce the carbon footprint of the product. The process according to the invention thus makes it possible to utilize or combine cheaper, crude, starting materials or purified raw materials. This also makes use of the side fractions of the fractionation process.

The manufacturing method according to the invention also has the advantage of environmental friendliness, simple technology and low energy consumption. Energy consumption can be reduced by utilizing the energy of the gas streams used in the different process steps by recovering them and utilizing them, for example, in preheating. In addition, volatile components used for flotation can be recycled

20185748 prh 07-09- 2018 by condensing and reusing. The volatile fractions generated in the carbonization step can also be utilized as a source of energy or heat can be recovered from them by condensation, in which case these liquid fractions can also be utilized in other processes. Non-condensable gases can be burned and the energy produced in this way can be utilized, for example, in process, heating or electricity generation.

The porous material according to the invention also has the advantage of being recyclable and reusable. The produced porous material can be directly regenerated by heating or alternatively by crushing, after which it can be used as a raw material for a new foam. Finally, the carbonized material can be used as a soil improver, allowing the carbon (CO2 negative) it contains to be stored in the soil for a long time, or alternatively it can be burned to produce green energy.

In the following, preferred embodiments of the invention will be examined in more detail with reference to the accompanying drawing. The drawing shows a simplified schematic diagram of the steps of one method according to an applicable form.

Drawings

Fig. 1 is a block diagram showing the steps of a method according to one embodiment.

embodiments

The present invention relates to a porous molding material and a method for producing the same.

The products to be manufactured are hereinafter referred to as “body” and “foam body” 30 as synonyms for each other. It is a three-dimensional body that is porous.

After flotation, the porous material comprises mainly macroporous. Typically, the smallest dimension of the pores is then at least 0.01 mm. As a result of activation

20185748 prh 07-09- 2018 a large number of micropores and mesopores are formed in the body.

Preferably, the body is porous throughout, which means that the porous structure extends from inside the body to its surface. Preferably, the porous body, i.e. the foam body, is permeable to gases.

The bodies are “monolithic”, which in this context means that their body structure consists of the same substance throughout, i.e. the body is “one substance”.

The pieces are typically mechanically strong and it is possible to make self-supporting pieces from the present material. “Self-supporting” means that they can be used to form products, such as filters and similar pieces, that do not require a separate body layer or structure.

The method according to one embodiment is shown in Figure 1.

In the first step of the process (reference number 2 in Fig. 1), a mixture containing a liquid medium is formed from a lignin-containing fraction obtained from biomass fractionation 1.

Typically, the lignin-containing fraction is derived from biomass, such as wood or annual or perennial plants. The fraction is obtained, for example, by extracting the biomass with aqueous solutions, for example by hot water extraction or pressurized hot water extraction or by conventional chemical pulp cooking. Aqueous solutions preferably contain lignin-dissolving components such as alkalis, e.g., alkali metal or alkaline earth metal hydroxides, carbonates, sulfides, or mixtures thereof. Extraction solutions may also contain peroxides as well as organic compounds such as perforic acid or Caron's salt.

The novelty can also be performed with organic or ionic solvents.

The liquid medium contained in the mixture acts as a foamer in the mixture. In one embodiment, the liquid medium is water. According to another embodiment, the liquid medium may be, for example, an organic solution such as an alcohol, or

20185748 prh 07-09- 2018 ionic solution. The liquid medium may also be a mixture of several different liquids. By using a liquid medium with a low boiling point, the energy required to dry the foam can be reduced.

In one embodiment, the liquid medium used for flotation can be collected and recycled for reuse.

The lignin may be either untreated or treated or a mixture thereof. Thus, the lignin may be in any form, such as an alkaline lignin, a thiol form, or a metal salt of a lignosulfonate.

According to one embodiment, other fractions from biomass fractionation 1 are also added to the lignin-containing mixture. These fractions may or may not contain lignin. Typically, the fractions to be added contain, for example, organic components from biomass, such as extractants, furfural or tannin, or monomeric, oligomeric or polymeric saccharides derived from cellulose or hemicellulose.

In addition, the fractions to be added may be pure or unpurified. The proportion of each such fraction 20 in the solids of the mixture to be foamed may be, for example, about 0.1 to 25% by weight.

Thus, the present invention is able to efficiently utilize various by-products of the fractionation process.

According to one embodiment, the mixture formed from biomass fractions contains at least 1% by weight of lignin, preferably at least 5% by weight of lignin, more preferably 10-80% by weight of lignin, for example 20-50% by weight of lignin, based on the dry weight of the mixture.

According to one embodiment, the mixture formed from the fractions contains at least 1% by weight of lignin, preferably at least 5% by weight of lignin, more preferably 10-75% by weight of lignin, for example 30-50% by weight of lignin, based on the total weight of the mixture.

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According to one embodiment, the mixture formed contains 0.1 to 70% by weight of liquid medium, preferably 1 to 50% by weight, more preferably 5 to 30% by weight, for example about 10% by weight, based on the total weight of the mixture.

Components can also be added to the mixture, which, for example, modify the properties of the final product according to the application.

In one embodiment, these components are added prior to flotation. According to another embodiment, these components can also be added at any other stage of the process, such as before drying or carbonization, or at several different stages.

In one application, a substance or substances belonging to one or more of the following groups are added to the mixture:

a substance which modifies the mechanical properties of the articles to be manufactured (in particular substances which increase their strength), a substance which modifies the fire and rot resistance of the articles to be manufactured, a catalyst or an insecticide in the articles to be manufactured.

Furthermore, it is also possible to add various fillers, wetting agents and.

stabilizers.

The total amounts of the above substances and components are typically about 0.0125% by weight, especially about 0.1-10% by weight based on the dry weight of the starting material.

The mixture formed in the next step 3 of the method is foamed and shaped in a mold to a predetermined shape.

According to one embodiment, the mixture formed from the fractions obtained as a result of the fractionation of the biomass is foamed before it is fed into the mold, whereby the mold is thoroughly filled and the foamed body is made exactly mold-shaped. According to another embodiment, the mixture is only foamed in a mold. The mold may be heated to promote foam solidification, as described below.

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The mixture can be foamed by any commonly known flotation method, such as heating, mechanical stirring, a blowing gas process, or a brine process. Preferably, the mixture is foamed by mechanical agitation or chemically. For example, sodium carbonate or potassium carbonate can be used in chemical foaming, which decomposes to produce carbon dioxide and whose alkali moiety also acts as an activation aid. Flotation can be performed, for example, in a mixed tank.

To promote foaming, a blowing agent such as a surfactant such as polysorbate may be added to the mixture, e.g., about 0.1-10% by weight of the dry matter of the mixture.

According to a preferred embodiment, the flotation is carried out at normal pressure or low overpressure, for example at an absolute pressure of 1.1 to 10 bar. The foam temperature is preferably above 20 ° C but below 100 ° C. The reaction is exothermic, i.e. without heating the flotation is more controllable and the shaping of the part is easier.

With the help of the mold, the foamed product acquires a clear shape in three dimensions, which is in no way limited. It can be, for example, a cube, a cone, a cylinder or a ball. According to a preferred embodiment, the mold must be closed. However, the mold can also be open.

The shaped porous material prepared as described above is subjected to a heat treatment 4.

The formed porous material is heat treated at 4 mild temperatures to strengthen the foam 25. In a preferred embodiment, the heat treatment is performed while the foam is still in the mold.

However, the heat treatment can also be performed in a separate oven.

The heat treatment is carried out by heating the foamed mixture to a suitable temperature and maintaining it at this temperature for a sufficient time, such as 0.1 to 24 hours, for example 0.5 to 12 hours, depending on the composition of the mixture formed from the fractions. Advantageously

20185748 prh 07-09-2018 the heat treatment takes place at a temperature below 250 ° C, for example at a temperature below about 200 ° C, preferably at a temperature of about 101-195 ° C. Usually the heat treatment is carried out at normal atmospheric pressure (at a pressure of about 1 bar), but it is of course also possible to carry it out at an elevated pressure, e.g. at an absolute pressure of about 1.1-10 bar.

The temperature of the foam should be raised at a sufficiently low rate to allow the material to heat evenly. According to one embodiment, a suitable heating rate is about 1-120 ° C / minute, in particular the temperature is raised in a heat treatment vessel about 5-50 10 ° C / minute, for example about 10-30 / ° C / minute.

According to one embodiment, the temperature of the heat-treated porous material is preferably lowered to a temperature of about 50-100 ° C. The lowering of the temperature is preferably carried out so slowly that there are no cracks in the carbon foam due to thermal stress.

A suitable cooling rate is about 1-120 ° C / minute, especially the temperature in the heat treatment vessel is lowered to about 5-50 ° C / minute, for example about 10-30 / ° C / minute. This is typically done if the shaped porous body is removed from the mold at this point and the following method steps are performed without the mold. Typically, the porous body is also held in the mold by carbon during germination and activation, if the mold is such that the gases released during carbonization and activation can pass freely therein.

In another, preferred embodiment, the heat-treated porous material is taken directly, without substantially lowering its temperature, to the next process step, where it is charred and activated.

According to a preferred embodiment, the carbonization 5 after the heat treatment takes place in the inert gas phase at a temperature above 500 ° C, such as at a temperature of 500-1500 ° C, preferably at a temperature of about 800-1000 ° C. The temperature of the foam is slowly raised to the carbonation temperature. A suitable heating rate is about 1-120 ° C / minute, especially the temperature in the heat treatment vessel is raised to about 5-50 ° C / minute, for example about 1030 / ° C / minute.

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The inert gas phase used in carbonization may contain any gases that are substantially inert under the conditions of carbonization. Examples of such gases are nitrogen, helium, carbon dioxide and argon and mixtures thereof.

Carburization can be performed in a sealable reactor or furnace. Typically, such a reactor or furnace operates at near atmospheric pressure or at low overpressure.

According to one embodiment, even after carbonization, the temperature of the body should decrease slowly enough so that no cracks occur in the body. A suitable cooling rate is about 5-50 ° C / minute.

In another preferred embodiment, the carbonized porous material is taken directly, without substantially lowering its temperature, to the next possible process step in which it is activated.

According to a preferred embodiment, the carbonized body is activated to further increase its specific surface area. It is by the method of the present invention that the material is first uniformly carbonized and then activated throughout.

The carbonization and activation steps of the material also increase the mechanical strength of the porous material.

In one embodiment, the body is chemically activated. Preferably, the chemical activation occurs by heating the material treated with the activation chemicals to a temperature of 400 to 800 ° C. Activation chemicals are used to remove moisture from the material. For example, alkali salts, phosphoric acid, zinc chloride or sulfuric acid or a mixture thereof can be used as activating chemicals.

According to another embodiment, the body is physically activated, wherein the carbon is activated by gas at a temperature of about 800-1100 ° C. The gas used can be, for example, water vapor, carbon dioxide or a mixture thereof. As a result of exothermic reactions of activation, hydrogen, carbon monoxide and carbon dioxide are removed from the material.

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According to a preferred embodiment, the body is activated with steam. In this case, the external adsorption surface of the activated material becomes large and the structure becomes small pores, whereby the foam mainly comprises micropores (pores below 2 nm) and mesopores (pores 2-50 nm), respectively.

According to a preferred embodiment, the specific surface area of the body after activation is more than 500 m ² / g, which corresponds to the minimum surface area requirement for activated carbon. More preferably, the specific surface area of the body after activation is more than 600 m / g, for example 750-2500 m / g.

According to a preferred embodiment, the pore volume of the body after activation is more than 0.3 cm '/ g. More preferably, the pore volume of the body after activation is greater than 0.4 cm / g, for example 0.5-0.7 cm / g.

According to one embodiment, the carbonized porous body can be further graphitized before activating the body by heating the body to an even higher temperature, above 1500 ° C. Graphitization can further modify the properties of carbon foam.

According to one embodiment, even after activation, the temperature of the body must decrease slowly enough so that no cracks occur in the body. A suitable cooling rate is about 5-50 ° C / minute.

In one embodiment, the porous carbonized body 25 produced by the method can be washed to reduce any inorganic materials. The washing can be carried out, for example, with water, aqueous acids, bases or some other solution, especially an aqueous solution. The body can then optionally be dried by well-known drying methods.

According to one embodiment, impregnates can be added to the starting material, i.e. additives which further improve, for example, the adsorption of certain substances on the material during its use. The amount of such substances is typically about 0.1-10% by weight.

20185748 prh 07-09- 2018 on the dry weight of the starting material.

Based on the above, the method according to the invention comprises in the first embodiment 1) fractionation of biomass and formation of a liquid medium mixture 5 from fractions, at least one of which contains lignin, 2) placing the mixture in a closed mold, 3) foaming the mixture, 4) heat treating the porous material to foam; carbonizing the reinforced foam and 6) finally activating the carbonized body.

In another embodiment, the method of the invention comprises 1) fractionating biomass and forming a liquid medium mixture of fractions, at least one of which contains lignin, 2) foaming the mixture, 3) placing the porous material in a closed mold, 4) heat treating the porous material to reinforce the foam, 5) reinforcing the foam; and 6) finally activation of the carbonized body.

According to one embodiment, efficient energy use can be combined with the method according to the invention when utilizing the energy of the gas streams used in the different process steps. Such a process diagram is shown in Figure 1.

According to one embodiment, the volatile fractions generated in the carbonization step of the process according to the invention are condensed, whereby thermal energy is recovered from them. At the same time, liquid fractions are formed that can be utilized in other processes. Liquid fractions can be recovered or incinerated.

According to another application, which can also be combined with the previous one, the volatile fractions in the carbonization stage and, in the previous application, possibly non-condensable gases are burned to produce energy. The generated energy can be utilized, for example, in process, heating or electricity generation.

According to one embodiment, the recovered thermal energy can be utilized in the internal heating of the process, i.e. in the raw materials or building.

20185748 prh 07-09- 2018 in the heating. According to another embodiment, thermal energy can be sold to external houses.

The carbon content of the porous body of the present invention depends on the starting material used and the temperature used in the carbonization or graphitization of the foam.

According to one embodiment, the carbon content of the finished porous body is 50 to 100% by weight, preferably 75 to 100% by weight, for example 80 to 98% by weight, based on the weight of the finished body.

According to one embodiment, the porous body according to the invention has a density of 20950 g / dm ³ , preferably 50-500 g / dm ³ and a compressive strength of about 0.07-7 MPa, preferably about 0.1-1.0 MPa.

The present invention also relates to a porous body made by the method of the invention.

In addition, the present invention relates generally to a porous, monolithic, self-supporting and shaped body made from a lignocellulosic lignin-containing starting material that is carbonized and activated throughout.

eXAMPLES

Example 1

First, 150 g of water, 200 g of furfuryl alcohol and 25 g of surfactant (polysorbate) were mixed together until they formed a homogeneous mixture. Then, 200 g of powdered lignin and 200 g of tannic acid were added to the mixture, after which the mixture was stirred vigorously for several minutes. In the third step of forming the mixture, 50 g of a volatile compound (n-pentane) was added. Finally, 100 g of an acid catalyst (para-toluenesulfonic acid) was added, which started the reaction and foaming began as a result of the chemical reaction.

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After the foaming had stabilized, the mixture was placed in a mold and transferred to an oven to consolidate the foam. The foam was kept in the oven for 1200 minutes at 110 ° C.

After solidification, carbonization was performed in the inert gas phase by raising the temperature of the foam to 550 ° C. After carbonization, the body was activated at 800 ° C using steam as the activating gas. After activation, the body temperature was lowered to room temperature and the finished porous body was removed from the mold.

Industrial applicability

The method according to the invention can be utilized for the production of various porous mouldable materials, and the material produced by the method can generally be widely used for various industrial applications. The material can be used as such or used as a starting material in other processes.

The produced activated porous material can be utilized e.g. in various cleaning applications, such as cleaning gases and liquids, and in cleaners and filters, such as fresh air filters for cars.

Other applications for the material according to the invention are, for example, use as a filler, as a catalyst filler, for the storage of gases and as a porous electrode.

The invention is not intended to be limited to the embodiments exemplified above, but rather to be broadly construed within the scope defined by the claims set forth below.

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Reference numbers for biomass fractionation

2nd mixture

3. flotation and shaping

4. heat treatment

5. activation and activation

reference Publications

Patent literature

US 3894878 A

WO 2005016818 A1

CN 1070021486 A

CN 106587001 A

US 4552863

WO 2018085918 A1

Other literature

Tondi, G., Pizzi, A., Celzard, A. (2010) Tannin based foams and its derived carbon foams. Processing Technologies for the Forest and Biobased Products Industries, Kuehl / Austria.

Pizzi, A., Celzard, V., Tondi, G. (2012) Chemistry, morphology, microtomography, and activation of natural and carbonized tannin foams for different applications. Special Issue: Functional Polymeric Materials and Composites, Volume 313-314: 1, 100-111.

Claims (17)

The claims 1. A process for the preparation of porous bodies from a lignocellulosic starting material, the process comprising: - forming a mixture of lignin-containing fraction from biomass fractionation containing a liquid medium, 5 - any other fractions from biomass fractionation are added to the mixture, the mixture is foamed and shaped to a predetermined shape by means of a mold, and - the shaped mixture thus obtained is subjected to a heat treatment, after which it is carbonized, characterized in that the carbonized body is activated in order to increase its specific surface area. Method according to Claim 1, characterized in that the mixture is foamed before it is fed into the mold. Method according to Claim 1 or 2, characterized in that it is liquid The medium is water, an organic solution or an ionic solution or a mixture thereof. Process according to one of the preceding claims, characterized in that the mixture is foamed mechanically by stirring or chemically. 20 Process according to one of the preceding claims, characterized in that the mixture is foamed at an absolute pressure of 0.1 to 10 bar and at a temperature below 100 ° C, preferably at normal pressure and at room temperature. Method according to one of the preceding claims, characterized in that The method uses an open or closable mold in which the foamed product is formed into a three-dimensional body, such as a cube, cone, cylinder or ball. Method according to one of the preceding claims, characterized in that the porous material is heat-treated at less than 250 ° C, preferably below 200 ° C, More preferably at 75-150 ° C, to strengthen the foam. 20185748 prh 07-09- 2018 Method according to one of the preceding claims, characterized in that the heat treatment is carried out in a mold, in particular the heat treatment is carried out in a mold in which the foam body is shaped without removing it from the mold. Process according to one of the preceding claims, characterized in that the foam body is carbonized in the inert gas phase at a temperature of more than 500 ° C, preferably at a temperature of 600-1200 ° C. Method according to one of the preceding claims, characterized in that the foam body is activated by steam, preferably having a specific surface area of more than 500 m ² / g and / or a pore volume of the micropores and meso pores of preferably more than 0.3 cm 7 g. Process according to one of the preceding claims, characterized in that the mixture contains at least 1% by weight of lignin, preferably at least 5% by weight of lignin, more preferably 10-80% by weight of lignin, for example 20-50% by weight of lignin, based on the dry weight of the mixture . Method according to one of the preceding claims, characterized in that The lignin-containing fraction is obtained by treating biomass, such as wood or annual or perennial plants, with an aqueous solution containing lignin-solubilizing agents, such as alkali, or with an organic or ionic solvent. Method according to one of the preceding claims, characterized in that the foam body strength agents, anti-mold agents, flame retardants, catalysts or mixtures thereof are added to the mixture before the mixture is foamed. Process according to one of the preceding claims, characterized in that the volatile fractions generated during the carbonization step are condensed or incinerated. A porous body made by a method according to any one of the preceding claims. 16. A porous, monolithic, self-supporting and shaped body made from a lignocellulosic lignin-containing starting material, carbonized and activated throughout. Use of a porous body according to claim 15 or 16 in cleaning applications, such as gas or liquid cleaning or purifiers, as a filler or as a catalyst filler.