Energy optimization of a manufacturing / packaging process for clear binders (bitumen)

Abstract

A process for manufacturing clear binders where the liquid is coated / encapsulated around the powder or, conversely, the liquid is coated by the powder, while the entire assembly is cryogenically cooled to stabilize it. This operation can be carried out in a coating screw, a mixer, or other equipment. The resulting product is then ready for bagging before being preheated at the point of use, for example, to a temperature in the range of 120-150°C. [Figure 1]

Description

Title of the invention: Energy optimization of a manufacturing / packaging process for clear binders (bitumen)

[0001] The present invention relates to the field of manufacturing and / or packaging processes for clear binders (bitumen).

[0002] In the road sector, light-colored plant-based binders are of great interest because of their environmental, practical and aesthetic advantages.

[0003] It should be noted that light-colored binders are characterized by their lack of pigmentation and sometimes their transparency, unlike traditional bituminous road binders, which are dark due to the presence of asphaltenes in bitumen. The family of light-colored binders includes plant-based binders, derived from bio-based materials, and synthetic binders ("mineral" or "hydrocarbon") composed primarily of petroleum products. This lack of dark pigmentation allows them to be easily colored with a wide range of light and bright colors. They also allow the natural color of aggregates to stand out for projects related to active transportation (bike paths, parking lots) and urban development (parks, schoolyards, city centers).

[0004] Combined with light-colored aggregates, they help reduce the urban heat island effect, since light-colored pavements absorb less solar radiation energy. At the same time, light-colored binders also serve to delineate specific traffic zones to improve user safety.

[0005] Plant-based (or "bio-based") clear binders are composed primarily of ingredients of plant origin and therefore have a high renewable carbon content. They are manufactured by mixing several bio-based organic compounds, modified or unmodified, to improve their resistance to oxidation. These compounds generally come from the wood sector used by the paper industry and are extracted from by-products that are now being repurposed. Examples include tall oil pitch and plant resins, whose resin compounds have a strong binding capacity.

[0006] Plant-based binders offer a number of advantages over hydrocarbon binders. Even though they still tend to oxidize more quickly and have lower softening temperatures, these alternative binders are already preferred solutions for aesthetic coatings, localized repairs, and low-traffic areas, with very interesting performance.

[0007] The volume of Life Cycle Assessment (LCA) data available on plant-based binders is still low due to Despite the relative newness of these solutions, studies conducted to date clearly demonstrate their potential to reduce the environmental impact of infrastructure. This can be explained, among other things, by: • the renewable nature of raw materials; • lower manufacturing temperatures; and • low ecotoxicity.

[0008] Furthermore, clear plant-based binders are compatible with applications for recycling asphalt aggregates and for use in emulsions for the production of cold-mix asphalt, further reducing the carbon footprint of construction sites compared to traditional methods. For these various applications, the formulator has considerable freedom to adapt the rheological and mechanical properties of the plant-based binder. Nature of ingredients, origin, proportions, additives: the possibilities are numerous for specifically tailoring the penetrability, softening temperature, or even the viscoelastic properties of plant-based binders.

[0009] Apart from the component assembly stage, the manufacturing processes are very similar to those used for bituminous binders. The same methods can therefore be used to process bio-based binders. However, to preserve the transparency of the binders and comply with current quality and safety standards, companies wishing to produce and apply plant-based binders must have dedicated machines and equipment, preferably mobile and of a size adapted to current production volumes.

[0010] The present invention then aims to propose a new method of production and packaging of bitumen or clear binders (vegetable-based).

[0011] A current process for manufacturing binders is known, comprising essentially the following steps: - we have a cold base powder, we proceed to grind it into a fine cold powder at a temperature typically in the range of 5°C-20°C; - we have a hot liquid (typically at 120°C-150°C), in particular what is called an "HMPL" (the technical term for "High Melting Point Liquid"); - all the components of the clear binder (liquid and solid) are then mixed and heated (for example around 110 to 150°C); - then, to carry out its conditioning, this mixture is cooled to a temperature typically between -10°C and ambient temperature; - the bagged material will be heated to the point of use, typically between 120 and 150°C.

[0012] We can therefore see that a significant amount of energy is required for these different stages.

[0013] As will be seen in more detail below, the present invention proposes to eliminate some of the heating steps of the current process as recalled above.

[0014] Indeed, in the existing process, a hot fluid is mixed with powder at room temperature. The resulting mixture is heated to a temperature equivalent to the hot fluid, i.e. typically around 120-150°C.

[0015] Since the fluid / powder ratio is usually around 50%, the energy required to heat the mixture is therefore very significant. This is especially true because in the subsequent cold-conditioning step, it is necessary to cool the entire mixture. This powder-fluid mixing step is usually crucial and cannot be omitted because the mixture needs to "mature" for several hours at this temperature (typically 110-150°C) to acquire certain physical properties.

[0016] However, for clear binders without sulfur compounds, the absence of this maturation step does not appear to impact the final performance of the clear binder. This step could therefore be eliminated in certain situations. In this scenario, it would then be possible to eliminate the heating of the powder and the cooling for conditioning, which would represent a substantial energy saving.

[0017] To achieve this, it is proposed to encapsulate the powder and the liquid: - either by coating the powder with an HMPL - or by coating an HMPL

[0018] In both cases, the resulting product is a solid product that can be directly dosed for packaging. This eliminates the packaging step by cooling, particularly by cryogenic cooling, which is in addition to eliminating the heating of the solid portion during mixing with the liquid.

[0019] We propose here to carry out an encapsulation process using a cryogenic fluid, for example: - in mixers of the meat mixer type, for example by injecting the cryogen at the bottom of the mixer (this is a "batch" mode process); or - in churns traditionally used for coating food products with a sauce, with liquid nitrogen injection (here again, it's a "batch" process); or - in cryogenic screws with liquid nitrogen injection (it is a continuous process). - or in a screw of the type described in document FR-3091467B1 in the name of the Applicant (continuous process).

[0020] The present technical proposal is based on subcooling the solid part with liquid nitrogen to then cause the liquid part to stick to this solid part and make the whole thing solid.

[0021] It is also proposed here, in the same equipment used for encapsulation, to cool and maintain the initial powder before grinding in order to optimize the particle size of the grinding of the powder and obtain a more regular particle size.

[0022] The attached [Fig. 1] provides a diagram of an embodiment of the invention detailing the various proposed steps, which will be further detailed below: - the initial cold powder (at room temperature for example) undergoes cryogenic grinding, for example in equipment such as that described in document FR3091492B1, allowing the obtaining of a cold powder at a temperature ranging for example from 5 to 20°C; - this powder may, if necessary, undergo subcooling in the range of 0°C to -60°C, according to a process option, in suitable equipment but in particular in the same equipment as that used for the grinding above; - Next, hot liquid (120-150°C) is introduced, and liquid is coated / encapsulated around the powder or, conversely, the liquid is coated with powder, while the whole is cooled to stabilize it. This operation can be carried out in a coating screw, in a mixer, or in other equipment; - the result is then ready for bagging, before moving on to practical use with preheating to 120-150°C.

[0023] The present invention relates to a method for manufacturing and possibly packaging clear binders comprising the following steps: - a cold base powder is available, in particular at room temperature, and it is ground by cryogenic grinding, allowing the obtaining of a cold powder at a temperature preferably in the range of 5 to 20°C; - this powder undergoes, where appropriate, according to a process option, subcooling in the range of 0°C to -60°C, in cryogenic cooling equipment, in particular in the same equipment as that used for said cryogenic grinding; - we have a hot liquid, the temperature of which is preferably in the range of 120°C to 150°C, preferably a liquid called "HMPL"; - hot liquid is introduced, and a coating / encapsulation of liquid is carried out around the powder or conversely i.e. the liquid is coated by powder, at the same time as the whole is cooled to stabilize it, this operation can be carried out in a coating screw, in a mixer or other equipment; - the result of the previous step being then ready for bagging, before going towards practical use with pre-heating at the point of use, for example to a temperature in the range of 120-150°C.

[0024] According to one embodiment of the invention, the coating or encapsulation operation is carried out by the intervention of a cryogenic fluid, for example: - in a meat mixer-type mixer, for example by injecting the cryogen into the lower part of the mixer; or - in a food coating churn using a sauce, with liquid nitrogen injection; or - in a cryogenic screw with liquid nitrogen injection.

Claims

Demands

1. A process for manufacturing clear binders comprising the following steps: - a cold base powder, in particular at ambient temperature, is made available and is ground by cryogenic grinding, making it possible to obtain a cold powder at a temperature in the range of 5 to 20°C; - this powder undergoes, where appropriate, according to an option of the process, subcooling in the range of 0°C to -60°C, in cryogenic cooling equipment, in particular in the same equipment as that used for said cryogenic grinding; - a hot liquid is made available, the temperature of which is in the range of 120°C to 150°C, preferably an "HMPL" liquid; - the hot liquid is introduced, and the powder is coated or encapsulated with liquid or vice versa.e to the coating of the liquid with powder, at the same time as a cooling of the whole to stabilize this whole, this operation can be carried out in a coating screw, in a mixer or other equipment; - the result of the previous step then being ready for bagging, before going to practical use with pre-heating at the point of use, for example to a temperature in the range of 120-150°C.

2. A method according to claim 1, characterized in that the coating or encapsulation operation is carried out by the intervention of a cryogenic fluid, for example: - in a meat mixer, for example by injecting the cryogen into the lower part of the mixer; or - in a food coating churn using a sauce, with injection of liquid nitrogen; or Again in a cryogenic screw with liquid nitrogen injection.

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