Use of biochar to reduce hydrogen sulfide emissions in a bituminous composition

Abstract

The present invention relates to the use of biochar to reduce hydrogen sulfide emissions in bituminous compositions, in particular bitumen / sulfur crosslinked polymer compositions.

Description

Title of the invention: Use of biochar to reduce hydrogen sulfide emissions in a bituminous composition. Technical field

[0001] The present invention relates to the field of bituminous compositions and their performance additives. The invention relates in particular to the use of biochar in bituminous compositions to reduce hydrogen sulfide emissions in said compositions. The invention also relates to a method for reducing hydrogen sulfide emissions during the application and use of bituminous compositions. Prior art

[0002] Bitumen, or bituminous binder, is the main hydrocarbon binder used in road construction and civil engineering. It is notably used for road surfacing and as a waterproofing material.

[0003] In order to be used as a binder in these different applications, bitumen must have certain mechanical and dynamic properties.

[0004] It has long been known that the properties of conventional bitumen compositions can be modified by the addition of polymers. For example, copolymers of an aromatic monovinyl hydrocarbon and a conjugated diene, and in particular of styrene and butadiene or styrene and isoprene, are particularly useful, since these copolymers have good solubility in bitumen compositions and the resulting bitumen / polymer compositions exhibit improved mechanical properties compared to bitumen alone.

[0005] The stability of these bitumen / polymer compositions can be improved by adding crosslinking agents such as chemically unbound sulfur, a polysulfide, and / or a sulfur-donating vulcanization accelerator. These agents allow in-situ crosslinking of the polymer, thus creating a more stable bond. The crosslinked bitumen / polymer compositions thus obtained are known by the English acronym "PmB," for Polymer-modified Bitumen, or "PmA," for Polymer-modified Asphalt. This crosslinking gives the bituminous compositions very good properties in terms of storage stability, cohesion, elongation capacity, and resistance to aging.

[0006] However, a problem associated with the use of sulfur in these crosslinked bituminous compositions is the release of hydrogen sulfide (H2S). During the crosslinking of polymers with sulfur, chemical reactions occur, resulting in the release of H2S as a by-product. This H2S emission can can occur during the crosslinking process, but also during the subsequent use of bituminous compositions, particularly under the effect of heat.

[0007] Furthermore, bitumen, being a product derived from crude oil, naturally contains sulfur compounds. During the refining and production of bitumen, some of these sulfur compounds can decompose and release H2S. During the storage, transport, or application of bitumen at high temperatures, thermal reactions can cause the release of H2S from the sulfur compounds present in the bitumen.

[0008] H2S is a colorless and toxic gas with a characteristic odor even at very low concentrations. Besides the risk of inhalation for workers and its unpleasant odor, H2S can react with metals present in infrastructure, leading to accelerated corrosion and can cause the formation of pyrophoric iron pyrite in storage tanks, thus increasing the risks of fire and explosion.

[0009] For reasons of safety and compliance with environmental constraints, the reduction or even the elimination of H2S emissions during the production of bituminous compositions constitutes an industrial challenge.

[0010] Solutions have been proposed in the literature to reduce H2S emissions during the preparation of bituminous compositions. In particular, the addition of an agent capable of trapping H2S (known by the Anglo-Saxon term "scavenger H2S") to the bituminous composition has been proposed.

[0011] WO2005 / 065177 describes the addition of organic or inorganic metallic salts in Bituminous compositions are used as agents capable of trapping hydrogen sulfide. The metallic salts can be based on zinc, cadmium, mercury, copper, silver, nickel, platinum, iron, and / or magnesium. The process implemented to reduce H2S emissions involves directly introducing the metallic salt into a reactor containing a pre-mixed composition of bitumen and a polymer. The metallic salt, added in bulk to the reactor, is then agitated while the crosslinking reaction occurs. WO2013 / 092531 proposes adding the same metallic salts to a distribution line after the preparation of the crosslinked bitumen / polymer composition in the reactor.

[0012] However, some of these metallic salts used to trap H2S, such as platinum, nickel or mercury, can be expensive and raise environmental concerns related to their production, use and disposal.

[0013] Furthermore, the effectiveness of metal salts may be limited. For example, in WO2015 / 071154, the applicant showed that some of these metal salts capable of neutralizing and / or trapping hydrogen sulfide are deactivated in the presence acidic additives such as phosphoric acid or polyphosphoric acid, commonly used in bituminous compositions to improve the consistency of bitumen.

[0014] There is therefore a need to develop new agents capable of effectively reducing and / or eliminating H2S emissions during the production and use of bituminous compositions, favoring solutions that are environmentally friendly, non-toxic, economical, and readily available. Furthermore, it is essential that these agents retain their effectiveness in the presence of other additives commonly used in bituminous compositions.

[0015] The applicant discovered that biochar has the surprising ability to effectively trap H2S and thus significantly reduce H2S emissions during the preparation processes of bituminous compositions, in particular crosslinked bitumen / polymer compositions. Summary of the invention

[0016] The invention relates to the use of biochar in a bituminous composition to reduce and / or eliminate and / or inhibit and / or suppress H2S emissions.

[0017] According to one embodiment, biochar is obtained from the thermochemical conversion of biomass selected from forest products; crop residues; animal waste; municipal waste and any of their mixtures.

[0018] Preferably, biochar is obtained from the thermochemical conversion of biomass selected from hardwoods, in particular ash wood; cereal husks; nut shells, in particular cashew nuts; food waste; coffee grounds and any mixture thereof.

[0019] According to one embodiment, the bituminous composition is a bitumen / crosslinked polymer composition.

[0020] Preferably, the polymer is chosen from statistical or sequenced copolymers of an aromatic monovinyl hydrocarbon and a conjugated diene, preferably from statistical or sequenced copolymers of styrene and butadiene.

[0021] Preferably, the polymer is crosslinked by a sulfur-donating crosslinking agent.

[0022] Preferably, the sulfur-donating crosslinking agent is chosen from elemental sulfur, hydrocarbyl polysulfides, sulfur-donating vulcanization accelerators, mixtures of such products together and / or with non-sulfur-donating vulcanization accelerators.

[0023] According to one embodiment, the quantity of biochar in the bituminous composition is from 0.1 to 50% by weight relative to the total weight of the bituminous composition.

[0024] Advantageously, hydrogen sulfide emissions in the bituminous composition are reduced to 50 ppm or less, preferably to 20 ppm or less, and even more preferably to 10 ppm or less.

[0025] According to one embodiment, the bituminous composition further comprises at least one non-bituminous binder, and optionally at least one additive.

[0026] Advantageously the non-bituminous binder is chosen from a bio-based binder, a binder derived from recycled materials or waste, or mixtures thereof.

[0027] Preferably, the bituminous composition comprises from 5% to 60% by weight of a non-bituminous binder, relative to the total weight of the bituminous composition, preferably from 5% to 40% by weight, more preferably from 10% to 30% by weight.

[0028] Preferably, the bituminous composition has a compound content measured according to ASTM D6866, greater than or equal to 5% by mass, relative to the total mass of the composition, preferably greater than or equal to 10% by mass, more preferably greater than or equal to 15% by mass.

[0029] Preferably, the bituminous composition has an eco-material content of at least 5%, preferably at least 10%, preferably at least 15%.

[0030] The invention also relates to a method for reducing and / or eliminating and / or inhibiting and / or suppressing H2S emissions in a bituminous composition, particularly during the production and / or use of a bituminous composition, the method comprising at least one step of introducing biochar into said bituminous composition.

[0031] Preferably, the process includes at least one step of heating the bitumen to a temperature between 90°C and 230°C for at least 10 minutes under stirring followed by a step of adding biochar, and optionally at least one additive, the reaction medium then being maintained at this temperature for at least 10 minutes under stirring.

[0032] According to one embodiment, the process further comprises a step of adding a polymer and a crosslinking agent, and a step of crosslinking the polymer with the crosslinking agent, it being understood that the bituminous composition is then a crosslinked bitumen / polymer composition.

[0033] According to one embodiment, the biochar is mixed with the bitumen, and optionally the additive, before the step of adding the polymer and the crosslinking agent.

[0034] According to another embodiment, the biochar is added to the bitumen / crosslinked polymer composition during the polymer crosslinking step by the crosslinking agent. Detailed description

[0035] The expression "consists essentially of" followed by one or more characteristics means that components or steps which do not significantly modify the properties and characteristics of the invention may be included in the process or material of the invention, in addition to the components or steps explicitly listed.

[0036] The expression "between X and Y" includes the bounds, unless explicitly stated otherwise. This expression therefore means that the interval in question includes the values ​​X, Y, and all values ​​from X to Y.

[0037] The different embodiments, variants, preferences and advantages described for each of the objects of the invention apply to all the objects of the invention and can be taken separately or in combination.

[0038] According to a first aspect, the invention relates to the use of biochar in a bituminous composition to reduce and / or eliminate and / or inhibit and / or suppress hydrogen sulfide (H2S) emissions.

[0039] The applicant discovered that biochar can act as an agent capable of trapping H2S, thus acting as an "H2S scavenger", in the processes of preparing and / or using bituminous compositions.

[0040] Biochar is distinguished by its bio-based nature and non-toxicity, making it safer than the agents classically used in the prior art to capture H2S in bituminous compositions.

[0041] Biochar also has the advantage of capturing H2S in bituminous compositions without being deactivated by other additives present in the composition, in particular acid adjuvants.

[0042] Bituminous composition, in the sense of the invention, means any composition comprising at least bitumen.

[0043] Preferably, the bituminous composition according to the invention comprises, in addition to bitumen, at least one other constituent, for example, at least one non-bituminous binder, at least one polymer, and / or at least one additive. In one embodiment, the bituminous composition is a composition of unmodified bitumen with a polymer.

[0044] According to another embodiment, the bituminous composition is a modified bitumen composition with a polymer, in particular a bituminous composition comprising at least one crosslinked polymer, preferably a polymer crosslinked with a sulfur-donating crosslinking agent.

[0045] For the sake of simplicity, the term "bitumen / crosslinked polymer composition" will be used hereafter to designate a composition comprising bitumen, a polymer and possibly other additives.

[0046] In the context of this invention, the terms "trapping H2S", "neutralizing H2S" and "capturing H2S" are used interchangeably. The terms "H2S emissions", "H2S release" and "H2S release" are also used interchangeably. Biochar

[0047] According to the International Biochar Initiative (IBI), biochar is defined as a solid material obtained by thermochemical conversion, in particular by heating and / or pyrolysis, of biomass in an oxygen-limited environment, or even in the total absence of oxygen.

[0048] In particular, the thermochemical conversion of biomass leads to the production of a complex mixture consisting mainly of hydrocarbon compounds of varying chain lengths. The mixture is then separated into different fractions according to their evaporation temperature. This yields, in particular, a gaseous fraction, a (bio)fuel fraction, an oily fraction, and also a residue. This distillation residue then constitutes the biochar.

[0049] Biochar differs from charcoal in its use (as a material of interest rather than as a fuel) and therefore in its environmental impact. Biochar acts as a carbon sink, unlike charcoal, whose combustion releases carbon dioxide into the atmosphere. Furthermore, biochar is generally in powder form, while charcoal is in lump form. It is also distinguished by a highly variable surface chemistry, depending on the processing method, typically flash pyrolysis (Li, L., Rowbotham, JS, Greenwell, HC, & Dyer, PW (2013). An Introduction to Pyrolysis and Catalytic Pyrolysis: Versatile Techniques for Biomass Conversion. In SL Suib (Ed.), New and future developments in catalysis: catalytic biomass conversion (173-208). Elsevier). Finally, unlike charcoal, biochar does not contain toxic polycyclic aromatic hydrocarbons.

[0050] The chemical and physical properties of biochar depend on several parameters including the nature of the starting biomass ("feedstock" in English) but also on the parameters of the thermochemical conversion process, in particular the pyrolysis conditions.

[0051] The nature of the starting biomass is not particularly limited. Thus, the biochar used in the present invention can be obtained from the thermochemical conversion of any type of biomass. For example, the biochar used in the present invention can advantageously be obtained from the thermochemical conversion of biomass selected from among forest products; agricultural crop residues; animal waste; municipal waste; and any mixture thereof.

[0052] Among forest products, one can notably mention hardwoods (also called hardwoods), for example maple, oak, ash, cherry, walnut, apple, and pear; and softwoods, such as coniferous woods including pine, spruce, and fir. Forest products may also include leaves, needles, or fruits (acorns, pine cones, etc.). Preferably, forest products are chosen from among hardwoods, and more preferably ash wood.

[0053] Among crop residues, we can mention in particular straw, for example maize straw, wheat straw or rice straw; bagasse (fibrous residue) obtained by crushing sugar cane; cereal husks; peanut shells; nut shells, in particular almonds, Brazil nuts, cashew nuts, hazelnuts, pecans or walnuts.

[0054] For the purposes of this invention, "cereal chaff" or "grain" refers to a co-product derived from the processing of cereals and consisting of the glumes and lemmas that enclose the grain. In other words, cereal chaff constitutes the outer layer in which the cereal grain is contained.

[0055] By way of example, we can mention corn husks, wheat husks, barley husks, sorghum husks, wheat husks, spelt husks as well as husks of any other cereal.

[0056] Preferably, the crop residues are chosen from cereal husks, nut shells, in particular cashew nut shells, and mixtures thereof.

[0057] Among animal waste, we can mention in particular slurry, manure or bedding from farm animals, especially poultry, pigs or cattle.

[0058] Among municipal waste, we can mention in particular food waste, especially organic waste such as peelings or coffee grounds, but also municipal biosolids.

[0059] For the purposes of this invention, "municipal biosolids" or sewage sludge refers to the material resulting from the treatment of municipal wastewater that is of sufficient quality to be recycled. It consists mainly of organic matter.

[0060] Preferably, municipal waste is chosen from food waste, coffee grounds and mixtures thereof.

[0061] According to a preferred embodiment of the invention, the biomass is selected from hardwoods, in particular ash wood; cereal husks; nut shells, in particular cashew nut shells; food waste; coffee grounds and any mixture thereof.

[0062] According to a still preferred embodiment, the biomass is chosen from ash wood, cereal husks, cashew nut shells, coffee grounds and any of their mixtures.

[0063] The process for converting biomass into biochar is not particularly limited. In particular, any thermochemical conversion process known to those skilled in the art can be implemented for the preparation of biochar for use according to the invention.

[0064] Suitable conversion processes are described for example in chapter 2 “Biochar for Maintaining Soil Health” of the book B. Giri, A. Vanna (eds.), Soil Health, Soil Biology 59. A. Tomczyk et al., “Biochar physichemical properties: pyrolysis temperature and feedstock kind effects”, Rev Environ Sci Biotechnol, February 5, 2020 also studies the impact of the choice of biomass and the thermochemical conversion conditions on the nature of the final biochar.

[0065] The conversion of biomass into biochar is typically carried out at a temperature greater than or equal to 350°C, preferably ranging from 350°C to 900°C.

[0066] Preferably, the biochar has a high carbon content, typically greater than 20% by mass, relative to the total mass of biochar, more preferably greater than or equal to 50%.

[0067] Advantageously, the biochar has a carbon content (also called total carbon content), determined by elemental analysis, ranging from 20% to 80% by mass, preferably from 50% to 75% by mass, relative to the total mass of biochar.

[0068] According to one embodiment, at least 80% of the carbon present in the biochar is biogenic, preferably at least 90%, more preferably at least 95%, advantageously at least 98%, more advantageously at least 99%. Advantageously, 100% of the carbon present in the biochar is biogenic.

[0069] For the purposes of this invention, "biogenic carbon" refers to the portion of carbon present in biochar that originates directly from biomass, in particular the portion of carbon fixed by the starting biomass through photosynthesis using atmospheric CO2. Biogenic carbon is thus distinguished from fossil carbon, notably by a difference in the ratio between the quantity of carbon-14 and carbon-13.

[0070] The proportion of biogenic carbon in biochar can be determined according to standard EN 16640, in particular standard EN 16640:2017.

[0071] Advantageously, biochar has a biogenic carbon content, measured according to standard EN 16640, ranging from 20% to 80% by mass, relative to the total mass of biochar, more preferably from 50% to 75% by mass.

[0072] Preferably, the biochar has an organic carbon content, measured according to ISO 9686, ranging from 1% to 60% by mass, more preferably from 2% to 50% by mass, typically from 3% to 45% by mass.

[0073] Preferably, the biochar has an inorganic carbon content, measured according to ISO 9686, ranging from 0.1% to 20% by mass, more preferably from 0.2% to 15% by mass, typically from 0.5% to 10% by mass.

[0074] Preferably, the biochar has a graphitic carbon content, measured according to ISO 9686, ranging from 5% to 90% by mass, more preferably from 7% to 80% by mass, typically from 10% to 75% by mass.

[0075] Preferably, the biochar has a low nitrogen N content, in particular less than or equal to 10% by mass, relative to the total mass of biochar, even more preferably ranging from 0.1% to 10% by mass, typically from 0.5% to 5% by mass.

[0076] Preferably, the biochar has a low phosphorus P content, in particular less than or equal to 10% by mass, relative to the total mass of biochar, even more preferably ranging from 0.01% to 10% by mass, typically from 0.05% to 7.5% by mass.

[0077] Preferably, the biochar has a low potassium K content, in particular less than or equal to 10% by mass, relative to the total mass of biochar, even more preferably ranging from 0.01% to 10% by mass, typically from 0.05% to 7.0% by mass.

[0078] Preferably, the biochar has a low calcium Ca content, in particular less than or equal to 15% by mass, relative to the total mass of biochar, even more preferably ranging from 0% to 15% by mass, typically from 0.01% to 10% by mass.

[0079] Preferably, the biochar has a low magnesium Mg content, in particular less than or equal to 10% by mass, relative to the total mass of biochar, even more preferably ranging from 0% to 10% by mass, typically from 0.1% to 3% by mass.

[0080] The content of nitrogen N, phosphorus P, potassium K, calcium Ca and / or magnesium Mg in the biochar can be measured by elemental analysis.

[0081] Preferably, the biochar has an oxygen O content, measured by elemental analysis, ranging from 0.1% to 50% by mass, relative to the total mass of biochar, more preferably ranging from 0.5% to 40% by mass, typically from 2% to 35% by mass.

[0082] Preferably, the biochar has a hydrogen content H, measured by elemental analysis, ranging from 0.01% to 20% by mass, relative to the total mass of biochar, more preferably ranging from 0.05% to 15% by mass, typically from 0.1% to 8% by mass.

[0083] According to one embodiment, the ratio between the mass of hydrogen present in the biochar and the total mass of organic carbon present in the biochar ranges from 0.01 to 5, preferably from 0.015 to 3, more preferably from 0.02 to 2.

[0084] According to one embodiment, the ratio between the mass of oxygen present in the biochar and the total mass of carbon (total carbon) present in the biochar, ranges from 0.01 to 5, preferably from 0.02 to 3, more preferably from 0.04 to 1.

[0085] According to one embodiment, the biochar is porous, preferably with open porosity.

[0086] For the purposes of this invention, "open porosity" means that the pores of the material are interconnected to form a continuous network. Therefore, all the pores of the material are accessible to water.

[0087] Preferably, the biochar has a porosity ranging from 10% to 90% by volume, more preferably from 30% to 85%, even more preferably from 50% to 85%.

[0088] Methods for measuring the porosity of a biochar are known to those skilled in the art. In particular, the methods described in CE Brewer, Biomass and Bioenergy, 66, 2014, 176-185, can be cited.

[0089] Advantageously, biochar has a specific surface area, measured according to the BET method defined in ISO 9277, ranging from 1.5 m2 / g to 500 m2 / g, more preferably from 5 m2 / g to 450 m2 / g, even more preferably from 10 m2 / g to 400 m2 / g.

[0090] Preferably, the biochar has a high pH, ​​typically greater than or equal to 5, more preferably ranging from 5 to 12, advantageously ranging from 6 to 10.

[0091] According to one embodiment, the biochar has a cation exchange capacity ranging from 1 cmol.Kg 1 to 100 cmol.Kg *, preferably from 1.5 cmol.Kg 1 to 80 cmol.Kg *, more preferably from 2 cmol.Kg 1 to 70 cmol.Kg *.

[0092] The methods for measuring the cation exchange capacity of a biochar are known to those skilled in the art. Examples include the Metson method and the Bower method.

[0093] According to one embodiment, the surface of the biochar is functionalized. Preferably, according to this embodiment, the surface of the biochar comprises at least one functional group selected from a phenol, a lactone (cyclic ester), a carboxylic acid, a carboxylic anhydride, a peroxide, an amine, a quinone, a chromene, an ether, a pyrone and any combination thereof.

[0094] Advantageously, the bituminous composition, in particular the bitumen / crosslinked polymer composition according to the invention, preferably comprises from 0.1% to 50% by weight of biochar, relative to the total weight of the bituminous composition, more preferably from 0.5% to 30%, even more preferably from 1% to 15%.

[0095] Advantageously, the use of biochar in the bituminous composition, in particular the bitumen / crosslinked polymer composition according to the invention, makes it possible to reduce hydrogen sulfide emissions to 50 ppm or less, preferably to 20 ppm or less, more preferably to 10 ppm or less, advantageously to 5 ppm or less.

[0096] In addition to being an agent capable of trapping and / or neutralizing H2S, biochar makes it possible to reduce the carbon footprint of the bituminous composition. Preferably, the use of biochar according to the present invention makes it possible to reduce the carbon footprint of a bituminous composition, in particular a bitumen / crosslinked polymer composition, by at least 10% compared to the same composition without biochar, more preferably by at least 20%, even more preferably by at least 30%, advantageously by at least 80%, more advantageously by at least 90%, typically by at least 95%.

[0097] According to another aspect, the invention relates to the use of biochar in a bituminous composition to reduce and / or eliminate and / or suppress the formation of pyrophoric iron pyrite in tanks where the bituminous composition is stored, and this by reducing H2S emissions in the bituminous composition.

[0098] According to another aspect, the invention relates to the use of biochar in a bituminous composition to reduce the corrosion of metals in infrastructure where said bituminous composition is used, and this by reducing H2S emissions in the bituminous composition. The bituminous composition

[0099] For the purposes of this invention, a bituminous composition means any composition comprising at least bitumen. Preferably, the bitumen composition according to the invention comprises, in addition to bitumen, at least one other constituent, for example, a non-bituminous binder, a polymer, and / or at least one additive.

[0100] According to one embodiment, the bituminous composition is a composition of unmodified bitumen with a polymer, in particular a composition comprising bitumen, optionally one or more bituminous binders, and optionally one or more additives but which does not comprise a crosslinked polymer.

[0101] According to another embodiment, the bituminous composition is a modified bitumen composition with a polymer (or crosslinked bitumen / polymer composition), in particular a bituminous composition comprising a bitumen and at least one crosslinked polymer, preferably a polymer crosslinked with a sulfur-donating crosslinking agent (or crosslinked bitumen / polymer composition), optionally one or more bituminous binders, and optionally one or more additives.

[0102] The use of biochar according to the invention makes it possible to obtain a final composition in which the biochar is included in the bituminous composition described above and in detail below. In this application, the quantities of the various compounds described are reported relative to the total weight of the bituminous composition comprising the biochar. The bitumen

[0103] The bituminous compositions according to the invention may contain one or more bitumens from different origins.

[0104] Examples include naturally occurring bitumens, those contained in deposits of natural bitumen, natural asphalt, or oil sands, and bitumens obtained from crude oil refining. In the context of this invention, the bitumens are advantageously selected from among those obtained from crude oil refining, particularly bitumens containing asphaltenes or pitches.

[0105] Bitumens can be obtained by conventional refining processes for bitumen production, in particular by direct distillation and / or vacuum distillation of petroleum. These bitumens may optionally be viscoreduced and / or deasphalted and / or air rectified. It is common practice to perform vacuum distillation of atmospheric residues from the atmospheric distillation of crude oil. This manufacturing process therefore consists of a succession of atmospheric distillation and vacuum distillation, with the feedstock for the vacuum distillation corresponding to the residues from the atmospheric distillation. These vacuum residues from the vacuum distillation tower can also be used as bitumens.It is also common to inject air into a feedstock typically composed of distillates and heavy products from the vacuum distillation of atmospheric residues from petroleum distillation. This process yields a blown, semi-blown, oxidized, air-rectified, or partially air-rectified base. The various bitumens or bitumen basestocks obtained through refining processes can be combined to achieve the best technical compromise.

[0106] According to the invention, for conventional processes for manufacturing bitumen basecoats, the manufacturing temperature is between 100°C and 200°C, preferably between 140°C and 200°C, and the mixture is stirred for a period of at least 10 minutes, preferably between 30 minutes and 10 hours, and more preferably between 1 and 6 hours. The manufacturing temperature refers to the heating temperature of the bitumen basecoat(s) before mixing, as well as the mixing temperature. The temperature and duration of heating vary depending on the quantity of bitumen used and are defined by standard NF EN 12594.

[0107] Blown bitumen can be manufactured in a blowing unit by passing a stream of air and / or oxygen through a starting bitumen base. This operation can be carried out in the presence of an oxidation catalyst, for example, phosphoric acid. Generally, blowing is performed at high temperatures, on the order of 200 to 300°C, for relatively long periods typically ranging from 30 minutes to 2 hours, continuously or in batches. The duration and temperature of blowing are adjusted according to the desired properties of the blown bitumen and the quality of the starting bitumen.

[0108] The bitumen used can also be chosen from fluxed bitumens by the addition of volatile solvents, petroleum-based fluxants and / or vegetable-based fluxants.

[0109] Among the usable bitumens according to the invention, recycled bitumens can also be mentioned.

[0110] Bitumens can be hard grade bitumens (such as grades 10 / 20 and 20 / 30) or soft grade bitumens (such as grade 160 / 220) as defined by standard EN 12591.

[0111] The invention is particularly suitable for cases where the bitumen base consists of a hard grade bitumen or a mixture of hard grade bitumens, in particular chosen from grade 35 / 50, 20 / 30 and 10 / 20 bitumens.

[0112] Preferably, the bitumen used in the invention has a needle penetration measured at 25°C according to standard EN 1426 of 5 to 330 1 / 10 mm, preferably of 20 to 220 1 / 10 mm.

[0113] Preferably, the bitumen used in the invention has a ring and ball softening temperature (RBW) according to standard EN 1427 of 50 to 175°C.

[0114] Preferably, the bituminous composition according to the invention comprises at least 40% by weight of bitumen, relative to the total weight of the bituminous composition, preferably at least 50% by weight, more preferably at least 60% by weight, advantageously at least 70% by weight, more advantageously at least 80% by weight, even more advantageously at least 85% by weight.

[0115] Advantageously, the bituminous composition according to the invention comprises from 40% to 99.9% by weight of bitumen, relative to the total weight of the composition, preferably from 50% to 99% by weight, more preferably from 60% to 95% by weight, even more preferably from 70% to 95% by weight, advantageously from 75% to 95% by weight, more advantageously from 80% to 95% by weight. The non-bituminous binder

[0116] According to one embodiment, the bituminous composition comprises at least one non-bituminous binder.

[0117] For the purposes of this invention, a non-bituminous binder is defined as a binder that does not contain bitumen, and in particular does not contain asphaltenes. The non-bituminous binder may be of natural origin, particularly based on renewable raw materials, or synthetic or a mixture of both. Preferably, the non-bituminous binder is a binder of natural origin based on renewable raw materials.

[0118] According to one embodiment, the bituminous binder may comprise at least one bio-based binder and / or a binder derived from recycled materials or from waste.

[0119] By "bio-based binder", according to the invention, a binder is understood to be entirely or at least partially made from bio-based compounds, that is to say, from materials of biological origin (for example, plant or animal) derived from renewable resources.

[0120] The integration of a bio-based binder into the bituminous composition makes it possible to reduce the carbon footprint of the final product while improving its mechanical properties and durability.

[0121] In particular, the bio-based binder is derived from materials obtained from renewable resources. Examples of these include vegetable oils such as soybean, linseed, rapeseed, and sunflower oil; used oils from the food industry, fatty acids and their derivatives; natural resins derived from rosin; lignin from the paper industry; as well as modified starches, natural polymers such as starch and cellulose, and semi-synthetic polymers such as cellulose ethers. Other examples include natural fibers such as cellulose, hemp, flax, and jute, and natural waxes such as beeswax.

[0122] In particular, the bio-based binder may advantageously comprise at least one plant-based plasticizer comprising an ester compound derived from tall oil and / or at least one plant-based structuring agent comprising at least one resin selected from natural rosins, modified rosins, rosin esters, and any mixture thereof. Such a bio-based binder is, for example, described in application WO2023 / 180360.

[0123] Advantageously, the bituminous composition has a content of bio-based compounds (included in the bio-based binder), measured according to ASTM D6866, greater than or equal to 5% by mass, relative to the total mass of the composition, preferably greater than or equal to 10% by mass, more preferably greater than or equal to 15% by mass.

[0124] The bio-based material content of a sample is typically determined by measuring the Carbon 14 (radioactive isotope of carbon) content present in said sample.

[0125] According to a preferred embodiment, the bituminous composition has a bio-based carbon content, measured according to ASTM D6668, of at least 5%, preferably at least 10%, preferably at least 20%, preferably at less than 75%, preferably at least 80%, more preferably at least 85%, advantageously at least 90%.

[0126] For the purposes of this invention, "binder made from recycled materials or waste" means a binder manufactured from recycled materials or industrial by-products. This includes, for example, recycled millings, recycled tire rubber, recycled plastics, recycled glass granules, and other similar materials.

[0127] Advantageously, the bituminous composition according to the invention can comprise from 5% to 60% by weight of a non-bituminous binder, relative to the total weight of the bituminous composition, preferably from 5% to 40% by weight, more preferably from 10% to 30% by weight.

[0128] Advantageously, the bituminous composition has a high eco-material content. The eco-material content can be defined by the following equation: Eco-material content = 100% - [% of non-bio-based, non-biodegradable, non-recycled or non-waste-derived materials], the percentages being expressed by mass, relative to the total mass of the bituminous composition.

[0129] Preferably, the bituminous composition has an eco-material content of at least 5%, preferably at least 10%, preferably at least 15%. The polymer

[0130] According to a preferred embodiment of the invention, biochar is used in a crosslinked bitumen / polymer composition.

[0131] The polymers used in bituminous compositions are well known in the art. They are mainly elastomers that can be crosslinked to form a network that improves the rheological properties of the bitumen. Examples of these polymers include polybutadiene, polyisoprene, butyl rubber, polyacrylate, polymethacrylate, polychloroprene, polynorbomene, polybutene, polyisobutene, and polyolefins. Other examples include copolymers of ethylene with various acrylates, methacrylates, anhydrides, and glycidyls, as well as terpolymers such as EPDM and ABS.

[0132] Preferably, the polymer is chosen from statistical or sequenced copolymers of a vinyl aromatic hydrocarbon, in particular an aromatic monovinyl hydrocarbon, and a conjugated diene.

[0133] The conjugated diene is preferably chosen from those having 4 to 8 carbon atoms per monomer, for example butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene and 1,2-hexadiene, chloroprene, carboxylated butadiene, carboxylated isoprene, in particular butadiene and isoprene, and mixtures thereof. Preferably, the conjugated diene is butadiene.

[0134] The monovinylaromatic hydrocarbon monomers of the copolymer may include known monovinylaromatic hydrocarbon monomers such as: styrene, o-methylstyrene, p-methylstyrene, p-tert-butylstyrene, 2,4-dimethylstyrene, alpha-methylstyrene, vinylnaphthalene, vinyltoluene and vinylxylene or mixtures thereof.

[0135] Preferably, the monovinyl aromatic hydrocarbon monomer is styrene, which can be used as an essentially pure monomer or as a major component in mixtures with minor proportions of one or more other structurally related aromatic vinyl monomers, such as o-methylstyrene, p-methylstyrene, p-tert-butylstyrene, 2,4-dimethylstyrene, alpha-methylstyrene, vinylnaphthalene, vinyltoluene and vinylxylene.

[0136] According to a preferred mode, the polymer is a copolymer of styrene and butadiene.

[0137] Advantageously, the polymer has a weight-average molecular weight Mw, measured by gel permeation chromatography with conventional detection and polystyrene standard, ranging from 10,000 to 600,000 g / mol, preferably from 40,000 to 500,000 g / mol, preferably still between 30,000 and 400,000 g / mol.

[0138] A particularly suitable polymer is a copolymer comprising at least one block obtained by polymerization of monovinylaromatic hydrocarbon monomers, typically styrene, designated S, and at least one block obtained by polymerization of butadiene, designated B.

[0139] Advantageously, styrene is used alone or in a mixture with at most 10% by weight of one or more other aromatic vinyl monomers, based on the total weight of the monomers in the S blocks of the polymer. The use of essentially pure styrene is particularly preferred.

[0140] Preferably, each block B is based on essentially pure butadiene monomers or monomers comprising minor proportions, up to 10% by weight, of structurally related conjugated dienes. Preferably, the blocks B consist exclusively of units derived from butadiene monomers.

[0141] Preferably, the content of monovinylaromatic hydrocarbons, preferably styrene, in the copolymer, determined by 13C NMR spectroscopy, is greater than or equal to 5% by weight, preferably between 5% and 50% by weight, more preferably between 15% and 40% by weight, relative to the total weight of the copolymer.

[0142] Preferably, the conjugated styrene-diene copolymer, in particular the styrene-butadiene copolymer, advantageously has a butadiene (1-2 and 1-4) content by weight ranging from 50 to 95%. The conjugated styrene-diene copolymer, in particular the styrene-butadiene copolymer, advantageously has a butadiene 1-2 content by weight ranging from 5% to 70%. Preference of 5 to 50%. The 1-2 butadiene motifs are the motifs that result from polymerization via the 1-2 addition of butadiene motifs.

[0143] Advantageously, the copolymer is chosen from among the triblock copolymers of styrene and butadiene.

[0144] More advantageously, the copolymer is chosen from among the SBS copolymers, where each S represents a block obtained by polymerization of monovinylaromatic hydrocarbon monomers, typically styrene, and B represents a block obtained by polymerization of butadiene.

[0145] According to a preferred embodiment, the polymer is chosen from linear copolymers, preferably from linear triblock copolymers.

[0146] Advantageously, the polymer is selected from linear triblock copolymers of styrene and butadiene. The DI 192A polymer marketed by KRATON is an example of this type of polymer.

[0147] Advantageously, the bituminous composition according to the invention comprises from 0.5 to 20% by weight of polymer, more preferably from 1 to 15% by weight, more preferably from 2 to 10% by weight, and more preferably from 2.5 to 7.5% by weight, of said bitumen / polymer composition. The crosslinking agent

[0148] The crosslinking agents usable according to the present invention are of a very varied nature and are chosen according to the polymer to be crosslinked in the bitumen / crosslinked polymer composition.

[0149] The crosslinking agent is advantageously chosen from the group consisting of elemental sulfur, hydrocarbyl polysulfides, sulfur-donating vulcanization accelerators, mixtures of such products together and / or with non-sulfur-donating vulcanization accelerators.

[0150] Elemental sulfur is advantageously sulfur in bloom and, preferably, crystalline sulfur in the orthorhombic form and known as alpha sulfur.

[0151] The vulcanization accelerators are either hydrocarbyl polysulfides, sulfur-donating vulcanization accelerators, or non-sulfur-donating vulcanization accelerators. The hydrocarbyl polysulfides may be selected from those described in FR2528439.

[0152] Sulfur-donating vulcanization accelerators can be selected from thiuram polysulfides, such as, for example, tetrabutylthiuram disulfides, tetraethylthiuram disulfides and tetramethylthiuram disulfides.

[0153] Non-sulfur-donating vulcanization accelerators may be sulfur compounds selected in particular from mercaptobenzothiazole and its derivatives, dithiocarbamates and their derivatives, and thiuram monosulfides and their derivatives.

[0154] Examples include zinc-2-mercaptobenzothiazole, zinc dibutyldithiocarbamate, and tetramethylthiuram monosulfide. Sulfur-donating and non-sulfur-donating vulcanization accelerators are described in particular in EP0360656, EP0409683, and FR2528439.

[0155] Preferably, the bituminous composition, in particular the bitumen / crosslinked polymer composition, comprises from 0.01% to 2% by weight of crosslinking agent relative to the total weight of the bituminous composition, preferably from 0.01% to 1% by weight, preferably again from 0.02% to 0.5% by weight. Additives

[0156] According to one embodiment, the bituminous composition according to the invention, and preferably the bitumen / crosslinked polymer composition, further comprises one or more additional additive(s).

[0157] By way of example, the following additives may be cited: a) Adhesion enhancers and / or surfactants. These are generally selected from alkylamine derivatives, alkylpolyamine derivatives, alkylamidopolyamine derivatives, and quaternary ammonium salt derivatives, used alone or in mixtures. The quantity of adhesion enhancers and / or surfactants present in the bitumen / polymer composition is, for example, between 0.2% and 2% by weight, preferably between 0.5% and 1% by weight, relative to the total weight of the bitumen / polymer composition. b) Waxes of animal or vegetable origin or hydrocarbon waxes, in particular long-chain hydrocarbon waxes, for example polyethylene waxes or paraffins, possibly oxidized. Amide waxes, such as ethylene bis(stearamide), may also be added. (c) Paraffins with chain lengths of 30 to 120 carbon atoms (C30 to C120). The paraffins are selected from polyalkylenes. Preferably, the paraffins are polymethylene paraffins and polyethylene paraffins. These paraffins may be of petroleum origin or may come from the chemical industry. Preferably, the paraffins are synthetic paraffins derived from the conversion of biomass and / or natural gas. d) melting agents, such as oils based on animal and / or vegetable fats or hydrocarbon oils of petroleum origin. Oils of animal and / or vegetable origin may be in the form of free fatty acids, triglycerides, diglycerides, monoglycerides or in esterified form, for example as methyl ester. e) resins of plant origin, such as rosin. f) antifoaming additives, including (but not limited to) selected from polysiloxanes, oxyalkylated polysiloxanes and fatty acid amides derived from vegetable or animal oils. (g) detergent additives and / or corrosion inhibitors, including (but not limited to) those selected from the group consisting of amines, succinimides, alkenylsuccinimides, polyalkylamines, polyalkylpolyamines, polyetheramines and imidazolines. (h) sliding agents or anti-wear agents, including (but not limited to) those selected from the group consisting of fatty acids and their ester or amide derivatives, including glyceryl monooleate, and mono- and polycyclic carboxylic acid derivatives. (i) additives modifying crystallization, additives inhibiting paraffin deposits, additives for lowering the pour point; low-temperature rheology modifiers, such as ethylene / vinyl acetate (EVA) and / or ethylene / vinyl propionate (EVP) copolymers, ethylene / vinyl acetate / vinyl versatate (EA / AA / EOVA) terpolymers; ethylene / vinyl acetate / alkyl acrylate terpolymers; graft-modified EVA copolymers; polyacrylates; acrylate / vinyl acetate / maleic anhydride terpolymers; amide copolymers of maleic anhydride / alkyl (meth)acrylate capable of being obtained by reaction of a maleic anhydride / alkyl (meth)acrylate copolymer and an alkylamine or polyalkylamine having a hydrocarbon chain of 4 to 30 carbon atoms, preferably of 12 to 24 carbon atoms;Amidated α-olefin / maleic anhydride copolymers that can be obtained by reacting an α-olefin / maleic anhydride copolymer with an alkylamine or polyalkylamine, the α-olefin being selectable from C10-C50 α-olefins, preferably C16-C20 α-olefins, and the alkylamine or polyalkylamine advantageously having a hydrocarbon chain of 4 to 30 carbon atoms, preferably 12 to 24 carbon atoms. j) antioxidants, for example of the hindered phenolic type or of the amino type, of the alkylated para-phenylenediamine type. k) metal passivators. 1) Acidity neutralizers. (m) Additives that lower the mixing temperature of asphalts and asphalt mixes, and those that improve the adhesion of bituminous binders to fillers and aggregates, such as, for example, polyisobutylene succinimides. n) acidic adjuvants, such as polyphosphoric acid, or diacids, in particular fatty diacids. m) organic and inorganic salts enabling the reduction of H2S emissions as described for example in WO2005 / 065177.

[0158] According to one embodiment, the bituminous composition does not include other agents for reducing H2S emissions other than biochar; in particular, the bituminous composition does not include organic and inorganic salts based on metals such as zinc, cadmium, mercury, copper, silver, nickel, platinum, iron, and / or magnesium.

[0159] Additives are used in quantities well known to those skilled in the art, depending on the nature of the additive, the bitumen base and the expected properties.

[0160] Preferably, when present in the bituminous composition, the content of additives varies from 0.1% to 10% by weight, preferably from 0.5% to 5% by weight, more preferably from 0.5% to 2.5% by mass, relative to the total weight of the bituminous composition.

[0161] Method for reducing H2S emissions in a bituminous composition

[0162] The present invention also relates to a method for reducing and / or eliminating and / or inhibiting and / or suppressing H2S emissions in a bituminous composition, the method comprising at least one step of introducing biochar into said bituminous composition.

[0163] The various embodiments, variants, preferences and advantages described above for biochar and its use according to the invention, as well as for bituminous compositions, also apply to the process according to the invention.

[0164] The bituminous composition can be prepared by any process known to those skilled in the art. Generally, these processes include mixing the components and heating the resulting mixture.

[0165] Generally, and as is known to those skilled in the art, bitumen is preheated and stirred before the other constituents of the composition are incorporated. Usually, the polymer and / or additives are added to the bitumen without having been preheated.

[0166] In particular, the bitumen is generally heated and agitated at a temperature in the range of 90 to 230°C, preferably in the range of 120 to 200°C, and preferably in the range of 150 to 180°C.

[0167] Advantageously, the incorporation of biochar according to the process of the invention is, in general, carried out while the bituminous composition is maintained at a temperature belonging to the range of 90 to 230°C, preferably to the range of 120 to 200°C, and preferably to the range of 150 to 180°C.

[0168] Preferably, heating is maintained throughout the process, and the heating temperature can be modulated during the process. Agitation can be maintained or interrupted intermittently as needed, or modulated during the process.

[0169] According to a first embodiment, the bituminous composition is a composition that is not modified by a polymer as described in detail above, and the process for reducing and / or eliminating and / or inhibiting and / or suppressing H2S emissions preferably comprises at least the following steps: - introduction of bitumen into a reactor, and possibly at least one non-bituminous binder and / or at least one additive as described above, - heating and stirring of the reaction mixture, - addition of biochar.

[0170] Alternatively, according to this first embodiment, the process may comprise, in the following order: - introduction of bitumen into a reactor, and possibly at least one non-bituminous binder, - heating and agitation of the bitumen, - addition of biochar, - addition of at least one additive as described above.

[0171] Preferably, according to this first embodiment, the bitumen, or possibly the bitumen / non-bituminous binder mixture, is heated to a temperature between 90°C and 230°C, preferably between 120°C and 200°C, more preferably between 150°C and 180°C. Advantageously, the heating is carried out for a period of at least 10 minutes, preferably between 20 minutes and 6 hours, more preferably between 1 hour and 5 hours.

[0172] Preferably, according to this first embodiment, the biochar is added while the reaction medium is maintained at a temperature between 90°C and 230°C, preferably between 120°C and 200°C, more preferably between 150°C and 180°C, for a period of at least 10 minutes, preferably between 20 minutes and 6 hours, more preferably between 30 minutes and 2 hours.

[0173] It is understood that the quantities of bitumen and the different components in the bituminous composition are those described in the preceding sections.

[0174] For example, the bituminous composition according to this first embodiment may comprise at least: - 40% to 99.9% bitumen by weight, - from 0.1% to 50% by weight of biochar, - possibly 5% to 60% by weight of non-bituminous binder, - possibly, from 0.1% to 10% by weight of one or more additives, the percentages being expressed in relation to the total weight of the bituminous composition.

[0175] According to a second embodiment, the bituminous composition is a bitumen / crosslinked polymer composition and the process for reducing and / or eliminating and / or inhibiting and / or suppressing H2S emissions includes the addition of biochar to said bituminous composition.

[0176] In particular, biochar can be added at different times during the preparation of the bitumen / crosslinked polymer composition.

[0177] The order in which the different constituents are introduced generally does not affect the properties of the final composition, although it is preferable to add the polymer before or at the same time as the crosslinking agent for better homogeneity. For example, according to a first embodiment, the biochar is mixed with the bitumen before the crosslinking step, in particular before the introduction of the polymer and the crosslinking agent.

[0178] Alternatively, according to a second variant, the biochar is added to the bitumen / crosslinked polymer composition after the addition of the polymer and the crosslinking agent, therefore after the polymer crosslinking step.

[0179] Alternatively, according to a third variant, the biochar is added to the bitumen / crosslinked polymer composition after the introduction of the polymer and before the introduction of the crosslinking agent.

[0180] Alternatively, according to a fourth variant, the biochar is added to the bitumen / crosslinked polymer composition after the introduction of the polymer and at the same time as the introduction of the crosslinking agent, i.e. during the polymer crosslinking step.

[0181] The biochar, the polymer, the crosslinking agent and possibly other additives can be introduced into the bitumen simultaneously or in a sequential manner.

[0182] According to one embodiment, the polymer and the crosslinking agent can be introduced simultaneously as a stock solution, according to any known method, during the preparation of the crosslinked bitumen / polymer composition. The stock solution generally comprises a hydrocarbon oil serving as a fluidizer, the polymer, and the crosslinking agent.

[0183] In particular, according to this second embodiment, the process according to the invention may preferably comprise the following steps:

[0184] - introduction into a reactor of a bitumen and a polymer as described above, and possibly at least one non-bituminous binder and / or at least one additive as described above, - Mix and stir until a homogeneous bitumen / polymer mixture is obtained - heating of the bitumen / polymer mixture, - addition of a crosslinking agent to the reaction medium, - addition of biochar, it being understood that these steps can be implemented in this order or in another order.

[0185] Alternatively, the method according to the invention may comprise, at least, the following steps: - introduction of bitumen into a reactor, and possibly at least one non-bituminous binder and / or at least one additive as described above, - heating and stirring of the reaction medium, - addition of biochar, - addition of a polymer as described above, - addition of a crosslinking agent, it being understood that these steps can be implemented in this order or in another order.

[0186] According to a particularly preferred embodiment of the invention, the process according to the invention comprises, at least, the following steps: - introduction of bitumen into a reactor, and possibly at least one non-bituminous binder and / or at least one additive as described above, - heating and stirring of the reaction medium, - addition of a polymer as described above, - addition of the crosslinking agent and biochar into the reaction medium.

[0187] Preferably, during the steps of adding the biochar and / or adding the polymer and the crosslinking agent, the reaction medium is maintained at a temperature between 90°C and 230°C, preferably between 120°C and 200°C, more preferably between 150°C and 180°C.

[0188] Preferably, the biochar is added to the reaction medium for a period of at least 10 minutes, preferably between 20 minutes and 6 hours, more preferably between 30 minutes and 2 hours.

[0189] It is understood that the quantities of bitumen and the different components in the bituminous composition are those described in the preceding sections.

[0190] For example, the bituminous composition according to this second embodiment may comprise at least: - from 40% to 99.9% by weight of bitumen, - from 0.1% to 50% by weight of biochar, - from 0.5% to 20% by weight of polymer, - from 0.01% to 2% by weight of crosslinking agent, - possibly, 5% to 60% non-bituminous binder, - possibly, from 0.1% to 10% by weight of one or more additives, the percentages being expressed by weight relative to the total weight of the bituminous composition.

[0191] According to another aspect, the invention also relates to a method for reducing and / or eliminating and / or suppressing the formation of pyrophoric iron pyrite in tanks where bituminous compositions are stored, thereby reducing H2S emissions from said bituminous compositions. Advantageously, the process comprises the same steps described above.

[0192] According to another aspect, the invention also relates to a method for reducing metal corrosion in infrastructure where a bituminous composition is used, by reducing H2S emissions in said bituminous composition. Advantageously, the method comprises the same steps described above. Brief description of the drawings

[0193] [Fig-1] represents the evolution over time of the ppm content of H2S released from a crosslinked bitumen / polymer composition without additive, in the presence of L233 as an agent for trapping H2S emissions according to the prior art and in the presence of biochar. Examples:

[0194] The invention is illustrated by the following examples given by way of non-limiting example.

[0195] In the examples, parts and percentages are expressed by weight unless otherwise indicated.

[0196] 1- Materials and methods: - Bitumen base grade 35 / 50 having a P25 penetration of 42 1 / 10 mm and a TBA of 52 °C and commercially available from the company TotalEnergies under the brand AZALT®.

[0197] - Polymer marketed under the reference Kraton® DI 192 A, which is a Styrene-butadiene linear block copolymer with a total styrene content of 30% by weight. The copolymer has a molecular weight (Mw), determined by triple-detection gel permeation chromatography, of 138,000 g / mol. - 100% plant-based biochar made from hardwood. - Zinc 2-ethylhexanoate (CAS No.: 136-53-8) marketed by BAERLOCHER under the name L233 - sulfur (CAS No.: 7704-34-9) marketed by POLYTECHS.

[0198] 2- Preparation of bituminous compositions A bitumen / polymer composition was prepared according to the following procedure: the bitumen was heated to 180°C. 3% by weight of Kraton DI 192 was added to this bitumen, followed by 0.06% by weight of sulfur, which was added to the mixture at 180°C, along with the scavenger (biochar or zinc 2-ethylhexanoate). The mixture was homogenized using a high-shear mill for 15 minutes. Samples were then taken regularly to measure the amount of H₂S released. The mixture was maintained at this temperature for a further 4 hours to allow for polymer crosslinking.

[0199] The details of the compositions are given in Table 1 below. The contents are expressed by weight, relative to the total weight of the bitumen / crosslinked polymer composition. Cl (comparative) C2 (comparative) C3 (according to the invention) STYRELF®* 100% 99.75% 90% Zinc 2-ethylhexanoate 0.25% Biochar 10%

[0200] *The control composition comprising bitumen and 3% crosslinked polymer is marketed by TotalEnergies under the brand name STYRELF®.

[0201] 3- Methods for measuring H2S emissions The measurement of H2S emissions is carried out using a conventional H2S titration method. This involves bubbling nitrogen gas through the bitumen / crosslinked polymer composition being tested, maintained at 185°C, followed by measuring the concentration of H2S trapped in the nitrogen gas using an H2S gas detector. The calculation of the H2S concentration in the liquid phase is based on the initial mass of the tested bitumen / crosslinked polymer composition.

[0202] This measurement is not intended to be representative of the H2S concentration present in the atmospheric gaseous atmosphere in real time, but rather to compare the effectiveness of H2S trapping agents used under identical conditions, by determining the presence or absence of H2S release. Thus, a threshold for H2S release has been established, above which we consider the agent's effectiveness to be insufficient.

[0203] 4- Results The evolution of the H2S release rate was monitored over time for the three prepared compositions. The results obtained are presented in Table 2 below and in [Fig. 1]. Cl C2 C3 Time (h) H2S Release (ppm) 0 195 159 83 0.5 48 3 1 64 34 1.5 27 1 2 20 15 1 3 8 4 5 1 6 2 24 1

[0204] These results show that biochar exhibits the best performance in terms of reducing H2S emissions. Biochar significantly reduces emissions as soon as it is introduced into the bituminous composition and maintains them at very low levels.

Claims

Demands

1. Use of biochar in a bituminous composition to reduce and / or eliminate and / or inhibit and / or suppress h2s emissions.

2. Use according to claim 1, wherein the biochar is obtained from the thermochemical conversion of biomass selected from forest products; crop residues; animal waste; municipal waste and any of their mixtures.

3. Use according to claim 2, wherein the biochar is obtained from the thermochemical conversion of biomass selected from hardwoods, in particular ash wood; cereal husks; nut shells, in particular cashew nuts; food waste; coffee grounds and any mixture thereof.

4. Use according to any one of claims 1 to 3, wherein the bituminous composition is a bitumen / crosslinked polymer composition.

5. Use according to claim 4, wherein the polymer is selected from statistical or sequenced copolymers of an aromatic monovinyl hydrocarbon and a conjugated diene, preferably from statistical or sequenced copolymers of styrene and butadiene.

6. Use according to claim 4 or claim 5, wherein the polymer is crosslinked by a sulfur-donating crosslinking agent.

7. Use according to claim 6 wherein the sulfur-donating crosslinking agent is selected from elemental sulfur, hydrocarbyl polysulfides, sulfur-donating vulcanizing accelerators, mixtures of such products together and / or with non-sulfur-donating vulcanizing accelerators.

8. Use according to any one of the preceding claims, wherein the amount of biochar in the bituminous composition is from 0.1 to 50% by weight relative to the total weight of the bituminous composition.

9. Use according to any one of the preceding claims, wherein the hydrogen sulfide emissions in the bituminous composition are reduced to 50 ppm or less, preferably to 20 ppm or less, preferably still to 10 ppm or less.

10. Use according to any one of the preceding claims, wherein the bituminous composition further comprises at least one non-bituminous binder, and optionally at least one additive.

11. Use according to claim 10, wherein the non-bituminous binder is selected from a bio-based binder, a binder derived from recycled materials or waste, or mixtures thereof.

12. Use according to claim 10 or claim 11, wherein the bituminous composition comprises from 5% to 60% by weight of a non-bituminous binder, relative to the total weight of the bituminous composition, preferably from 5% to 40% by weight, more preferably from 10% to 30% by weight.

13. Use according to any one of claims 10 to 12, wherein the bituminous composition has a compound content measured according to ASTM D6866, greater than or equal to 5% by mass, relative to the total mass of the composition, preferably greater than or equal to 10% by mass, more preferably greater than or equal to 15% by mass.

14. Use according to any one of claims 10 to 13, wherein the bituminous composition has an eco-material content of at least 5%, preferably at least 10%, preferably at least 15%.

15. A process for reducing and / or eliminating and / or inhibiting and / or suppressing H2S emissions in a bituminous composition, particularly during the production and / or use of a bituminous composition, the process comprising at least one step of introducing biochar into said bituminous composition.

16. A process according to claim 15, comprising at least one step of heating the bitumen to a temperature between 90°C and 230°C for at least 10 minutes under stirring followed by a step of adding biochar, and optionally at least one additive, the reaction medium then being maintained at this temperature for at least 10 minutes under stirring.

17. A method according to claim 16, further comprising a step of adding a polymer and a crosslinking agent, and a step of crosslinking the polymer with the crosslinking agent, it being understood that the bituminous composition is then a crosslinked bitumen / polymer composition.

18. A process according to claim 17, wherein the biochar is mixed with the bitumen, and optionally the additive, before the step of adding the polymer and the crosslinking agent.

19. Method according to claim 17, where , biochar is added to the bitumen / crosslinked polymer composition during the polymer crosslinking step by the crosslinking agent.