METHOD FOR REMOVING TOXIC AND EXPLOSIVE GASES AND CLEANING METAL SURFACES IN HYDROCARBON EQUIPMENT

Abstract

Method for rapid decontamination and for making hydrocarbon-contaminated equipment safe for entry (104) by sequencing a cleaning foam or spray, an encapsulating spray or foam, and a dry carrier gas.

Description

SYSTEM AND METHOD FOR THERMAL PROCESSING OF BULK MATERIAL USING INTENSE CONCENTRATED SOLAR ENERGY field of invention The present invention relates to a system, plant and method for the thermal treatment or processing of solid bulk material, for example, sand, limestone, mineral or metal, by means of concentrated solar radiation. Background of the invention Many solid materials in bulk form require massive heat treatment, in order to acquire certain properties, for example, for brittleness / embrittlement, to initiate chemical reactions, for example, for calcination, or simply to heat materials for further use. . The supply of thermal energy to such bulk solid material normally requires fuel combustion and produces polluting and greenhouse gas emissions, harmful to people and the environment, including carbon monoxide and dioxide, nitrogen dioxide, ozone , suspended particulate matter (PM), lead and sulfur dioxide. Similar problems are found in the valuable exploitation of thermal energy of solar origin when it comes to effectively achieving a conversion into electrical energy or another form of energy readily available to an end user, which includes industry. Brief description of the invention The technical problem raised and solved by the present invention is, therefore, to overcome the drawbacks mentioned above with reference to the state of the art and, in particular, to achieve an effective heat treatment of the solid bulk material. The above problem is solved by a system according to claim 1 and by a method according to claim 14. Preferred features of the invention are the subject of the dependent claims. The present invention solves the above technical problem by using concentrated solar energy to provide thermal energy to the bulk solid material received and transported by a high temperature resistant mechanical conveyor. The mechanical conveyor describes a route that passes through or under a heating, or high temperature, chamber in which solar radiation is concentrated. The mechanical conveyor is obtained, in a preferred configuration, using Magadi Superbelt® technology, based on a double-wire steel mesh that transports partially overlapping steel pans bolted and supported by upper rollers over its entire width. Compared to conventional chain conveyors, the mesh design ensures maximum reliability in the most severe conditions (such as very high temperature and abrasive materials). The mechanical conveyor may be manufactured in accordance with the disclosure of any of WO8704231A1, W02004110674 A1, W02007034289A1 or W003071189A1. The heating chamber includes an opening, preferably obtained in a side or upper wall thereof, for the admission of concentrated solar radiation. The heating chamber may include multiple internal surfaces, also as defined by the side walls and / or roof, i.e., the top wall, of the chamber. In a preferred configuration, the lower part of the chamber may be open and connected to, or associated with, the mechanical conveyor, in order to allow the passage of a linear length portion of the latter with thermal communication between the interior of the chamber. chamber and the bulk material received on the conveyor. The chamber may be provided with a hood for collection and delivery of hot air or other gas to a chimney or gas treatment devices. Therefore, a linear length of the mechanical conveyor is located below or within the chamber, such that the bulk material being transported receives thermal energy from the concentrated solar energy. Solar radiation can directly affect the bulk material, through reflections on the walls of the chamber and / or by re-irradiation from the walls. In the above configuration, the chamber is preferably lined internally with high temperature resistant tiles or refractory materials, which are exposed to solar energy entering directly through the opening and, indirectly, reflected and / or re-radiated by the walls of the chamber. chamber and the roof. Inside the chamber, behind the tiles or refractory surfaces, layers of thermal insulation can be installed to limit the dispersion of heat to the environment. High temperature tiles or refractory surfaces exposed to solar energy may have, in a preferred configuration, high reflection and emissivity, in order to maximize the release of solar energy to the material located below or within the chamber. To concentrate solar radiation in the heating chamber, an optical system may be provided. Such a system may include a field of heliostats to collect and concentrate solar radiation in the heating chamber, eventually through the interposition of one or more secondary reflectors. In the above configuration, the temperature of the bulk material can be increased to a desired value, for a desired time, suitable for performing a thermal or thermochemical process or for performing a desired heat treatment. In particular, under the effect of intense solar radiation energy within the heating chamber, the material transported on the mechanical conveyor is heated to high temperature values, for example, to a range of about 6001,000°C. The invention finds application in many industrial processes, such as limestone calcination, mineral comminution or embrittlement and decarbonization. For example, in the case of limestone calcination, the conveyor is fed with limestone, the solar energy is concentrated by an optical system in the chamber and / or the conveyor, with the walls of the chamber ultimately reflecting and / or re-radiating thermal radiation or energy to the belt conveyor. Under the effect of the intense concentration of solar energy, the temperature of the limestone increases to the calcination temperature and is converted into lime, which remains in the band, and CO2, which is extracted ηη£7 ίη / 77Ω7 / Β / ΥΙΛΙ of the camera and finally is treated additionally. The use of solar energy in processes reduces fuel and / or electricity consumption and CO2 emissions. The heat captured by the bulk material can also be used for other processes downstream of the heating chamber, for example, electrical power generation. Process parameters such as the speed of the conveyor, the thickness of the material on the conveying surface of the conveyor, the length and width of the conveyor under exposure to thermal energy in the chamber, can be selected and adjusted, to meet the specific conditions of a required thermal process. According to specific embodiments, downstream of the mechanical conveyor, a heat recovery system may be installed to extract (part of) the thermal energy contained in the hot material, for subsequent uses. For example, a solid particle to steam heat exchanger can be arranged downstream of the mechanical conveyor or along its route, in order to produce superheated steam that can be used for industrial purposes or, in turn, can drive a turbine. steam for electricity generation. To allow the continuity of the process, in the absence or in combination with solar radiation (night or cloudy weather), a conveyor casing or cover can be equipped with auxiliary heating elements, for example, radiant burners or IR radiant panels, which have the function of helping to heat the bulk material. Other advantages, features and modes of use of the present invention will become evident from the following detailed description of some embodiments, provided by way of example and not for limiting purposes. Brief description of the drawings Reference will be made to the figures of the attached drawings, in which: Figure 1 shows a plant design or system according to a preferred embodiment of the present invention, for application, for example, in limestone calcination; Figure 2 shows a plant design or system according to another preferred embodiment of the present invention, for its application, for example, in the brittleness, comminution or embrittlement of materials; Figure 3 shows a plant design or system according to a further preferred embodiment of the present invention, for application, for example, in the generation of electrical energy: Figure 4 shows a cross-sectional view of one embodiment of a heating chamber and a mechanical conveyor of any of the designs or plant systems of the previous figures. Detailed description of the invention Various modalities and variants of the invention will be described below, with reference to the figures already introduced. Generally speaking, analogous components are indicated in the various figures using the corresponding reference numbers. Other modalities and variants other than those already described will be explained only together with the relevant differences, if any, with respect to the previous ones. Furthermore, the characteristics of the various modalities and variants described below should be understood as combinable, when compatible. With initial reference to Figure 1, a plant, or system, for the calcination of a solid bulk material, in particular limestone, is denoted globally by 100. The bulk material is represented exemplarily and is denoted by B. The calcination system in Figure 1, and the process thus implemented, allow the production of lime, with the potential for CO2 recovery. Calcination of limestone is a decomposition process, according to the following chemical reaction: CaCOs = CaO + CO2. The chemical decomposition reaction in air for pure CaCOs begins at approximately 850°C. Calcination of calcium carbonate is a highly endothermic reaction, which begins when the temperature is above the dissociation temperature of carbonates in limestone, the latter commonly in the range of approximately 850-1,340°C. Once the reaction begins, the temperature must be maintained above the dissociation temperature and the CO2 generated in the reaction must be removed. According to the current embodiment, the system 100 comprises an optical arrangement 110 for concentrating solar radiation in a heating or high temperature chamber 130. A mechanical conveyor 150, in particular a belt conveyor, resistant to high temperatures, is also provided. and configured to transport the solid material in bulk. A length portion of the belt conveyor 150, denoted by 151, passes through or under the heating chamber 130. The direction of transport of the mechanical conveyor 150 is indicated by arrows in Figure 1. The optical system 110 comprises a field of heliostats, in particular a plurality of heliostats, one of which is denoted by 111. The heliostats 111 are located on the ground and solar radiation falls directly on them. Preferably, the optical system 110 comprises a tracking system that allows heliostats, or other optical elements, to track the apparent movement of the sun across the sky. The heating chamber 130 is, in the present embodiment, elevated above ground level, and is configured to receive concentrated solar energy reflected by the heliostats. To this end, a lifting support structure may be associated with the heating chamber 130 and / or the mechanical conveyor 150. In the present embodiment, the heating chamber 130 comprises several side walls or a side skirt 131, and a roof or top wall 132. One or more side walls of the heating chamber 130 are equipped with an opening, or opening, for the admission of concentrated solar radiation into the heating chamber 130. In the representation of Figure 1, a single opening is visible and is denoted by 135. In a preferred ηη£7 ίη / 77Ω7 / Β / ΥΙΛΙ embodiment, the inlet opening 135 puts the interior of the heating chamber 130 in direct communication with the external environment, being deprived, in use, of means closure or protection. The heating chamber 130 has internal wall surfaces, exemplarily denoted by 136 in Figure 1, comprising at least one reflective and / or re-radiating surface configured to reflect solar radiation entering the heating chamber 130 directly onto the length portion 151 of the mechanical conveyor 150 or on another reflective and / or re-radiating surface of the heating chamber 130. According to a specific embodiment, the internal surfaces or walls of the heating chamber 130 comprise a plurality of reflective surfaces, each configured to reflect solar radiation entering through the inlet opening 135, where the general configuration is such that the input radiation impinges on the bulk material downward from multiple reflections on the reflective surfaces. According to one embodiment, the internal surfaces or walls of the heating chamber 130 comprise a plurality of reflective and / or re-radiating surfaces that are configured to re-radiate within the chamber the thermal energy absorbed by solar radiation, advantageously according to a irradiating cavity configuration. Advantageously, the reflective and / or re-radiating surfaces have mutual viewing factors capable of reducing the output of radiant energy from the aperture 135. The aforementioned reflective and / or re-radiating surfaces, or at least one of them, have a reflectivity belonging to one of the following schemes: specular reflectivity, with a radiation reflection angle equal to the angle of incidence; diffuse reflectivity, with reflection in all directions, regardless of the plane of radiation incidence; bright reflectivity, with hybrid behavior between specular and diffuse reflectivity. In a preferred embodiment, the heating chamber 130 has a casing, for example, as defined by the wall 131 and 132, made (at least partially) of thermal insulating materials. Preferably, as in the present example, the bottom of the heating chamber 130 is open and connected to, or associated with, the conveyor belt 150. The heating chamber 130 may be provided with a hood and / or chimney 138 for the removal of CO2 and hot air, which helps the calcination process continue. The gas stream, containing CO2, can be delivered to one or more gas treatment devices, which preferably include a CO2 capture system and / or a waste heat recovery system. As mentioned above, the conveyor 150 is configured to receive the bulk solid material on a conveying surface 158 thereof, preferably in a substantially flat configuration, and to move the material from a loading region 155 to a discharge region 156. In the present embodiment, the conveyor 150 is based on a continuous belt, for example, driven by mechanical components known in the art. In the present example, the conveyor belt follows, as it travels forward or at least within or below the heating chamber 130, a substantially straight path. As mentioned above, the linear length portion 151 of the belt conveyor 150 is located below or within the heating chamber, 130 and allows the bulk material to receive thermal energy from concentrated solar energy. Solar radiation can directly affect the bulk material, through reflections on the walls of the chamber and / or by re-radiation from the walls. In other words, the belt conveyor 150 is thermally connected to the heating chamber 130 at its length portion 151, such that solar radiation entering the chamber 130 through the opening 135 transfers thermal energy to the material to be bulk being transported on belt conveyor 150. As mentioned above, preferably the heating chamber 130 is lined internally with high temperature resistant tiles and / or refractory materials, which directly receive the solar energy entering through the opening 135 and / or which indirectly receive the solar energy through reflection and / or re-radiation by the other walls of the chamber 131, 132. The heating chamber 130 is configured in such a way that the internal surfaces of its walls 131, 132 can present suitable viewing factors, suitable to maximize the emission of energy towards the bottom of the chamber, where the limestone is being transported. by mechanical conveyor 150. In a preferred embodiment, the bulk material has an absorbance value higher than that of the aforementioned reflective walls, to favor the rapid transfer of the energy reflected and / or re-radiated by the walls towards the material itself. In a preferred embodiment, the chamber surfaces have a high resistance to high temperatures, preferably greater than 1,000°C, and / or a reflectivity higher than that of the bulk material, preferably greater than 70% if calculated with reference to ASTM G173 and IS07668 standard regulations. Process parameters such as the speed of the conveyor, the thickness of the material on the conveyor, the length of the belt of the portion 151 under solar exposure, and the residence time under solar radiation, can be selected and adjusted to meet specific needs and conditions. of the calcination process. Under the effect of intense solar radiation inside the chamber, the temperature of the material increases to the desired calcination value, for the desired time, adequate to obtain the decomposition of the limestone. Depending on the size and geometry of the optical system, the mechanical conveyor 150 may also be located at a certain elevation above ground level, in which case an auxiliary conveyor system 160 is used upstream of the heating chamber 130 to raise the material and feeding it to the belt conveyor 150 in the loading region 155. For this purpose, a conventional lifting conveyor, such as a belt conveyor, hopper elevators or similar devices and systems, may be used. You can use an auxiliary conveyor 161 in the discharge region 156. ηη£7 ίη / 77Ω7 / Β / ΥΙΛΙ In the exemplary representation of Figure 1, an articulated route for bulk material is shown above the main belt conveyor 150 and the lateral auxiliary transport or lifting systems 160 and 161. In the plant configuration of Figure 1, a crushed material feeding device 170 and a heated material collecting device 180 are also shown, located upstream and downstream of the heating chamber 130, respectively. In a simplified embodiment, the mechanical conveyor may be a passive conveying surface, for example, a chute. Figure 2 refers to a second embodiment of a plant or system according to the present invention, which is configured in particular for the brittleness or embrittlement of minerals to improve comminution. The floor plan in figure 2 is globally denoted by 200. The fragility of the minerals makes it possible to reduce the electrical energy required for subsequent grinding, thus improving the overall mineral comminution process. Comminution is the process in which the mineral is reduced to the desired size, allowing maximum release of minerals, without changes in the chemical and physical properties of the mineral. There are several comminution methods, usually carried out in two stages, crushing and pulverizing / grinding. However, mineral comminution requires the majority of the energy consumed in mining operations, 30 to 70%, which in global terms is equivalent to a large amount of energy needed for the mining sector worldwide. For this reason, many sustainability initiatives have been designed to reduce energy consumption in mining and the associated CO2 emissions related to the use of fossil fuels for power generation and, generally speaking, provide a solution to improve the efficiency of energy consumption in comminution. One of the possibilities to reduce the electrical energy required for comminution is to embrittle the mineral through an appropriate phase of the thermal shock process. A conventional solution includes a phase of heating the mineral by fuel combustion, which however generates CO2 emissions, followed by a phase of rapid cooling of the mineral in water, which embrittles the minerals, but also requires availability of water. In accordance with the invention, the plant of Figure 2 employs concentrated solar energy to provide thermal energy to the mineral, transported as solid bulk material on a mechanical conveyor 250, in particular a belt conveyor, within or below a heating chamber. 230. The heating phase can be carried out, using system 200, in a very rapid manner and providing the required thermal shock that embrittles the mineral. Also in this embodiment an optical system is provided, denoted herein by 210 and includes a field of heliostats arranged on the ground and comprising a plurality of heliostats 211, or primary reflectors, similar to those already described. The heliostats 211 concentrate the incident solar radiation on one or more secondary optical elements ηη£7 ίη / 77Ω7 / Β / ΥΙΛΙ, in particular one or more secondary reflectors, one of which is represented in Figure 2 and is denoted therein by 212. Therefore, one or more secondary reflectors 212 are placed at the respective primary focal points, or foci, F1 of the heliostats 211. The secondary reflector 212 is located at a suitable elevation above ground level and is configured to receiving concentrated solar energy from the heliostats 211 and reflecting it at one or more (common) focal points, or foci, F2 that are located within the heating chamber and / or in a length portion 251 of the belt conveyor 250 arranged below or within the heating chamber 230. The heating chamber 230 has an upper opening 235 disposed in a roof wall 232 thereof. Therefore, the optical system 210 is configured as a downward beam focusing system, where solar radiation is reflected to impact the heating chamber 230 and / or the material on the belt conveyor 250 from above. Also in this case, process parameters such as the speed of the conveyor, the thickness of the material on the conveyor, the extension of the belt length portion 251 and the residence time under solar radiation can be selected and adjusted to meet the conditions. specific to the embrittlement process. Therefore, under the effect of intense solar radiation on the mechanical conveyor, the temperature of the material is increased to the desired value, with the requested temperature raising gradient, suitable to make the mineral brittle. Figure 3 refers to another embodiment of a plant or system according to the present invention, which is configured in particular for the collection of thermal energy from solar energy and for the subsequent or concomitant generation of thermal or electrical energy suitable for its exploitation by an end user. The floor plan in figure 3 is globally denoted by 300. Similar to the configuration of Figure 1, the plant or system 300 comprises an optical system 310 for concentrating solar radiation in a heating, or high temperature, chamber 330. A mechanical conveyor 350, in particular a belt conveyor, High temperature resistant is configured to transport a solid bulk material. A length portion 351 of the belt conveyor 350 passes through or under the heating chamber 330. The optical system 310 is provided, which comprises a field of heliostats, that is, a plurality of heliostats 311, located on the ground and on which solar radiation falls directly. The above components, and associated parts or elements, may be the same as those in Figure 1 and therefore will not be described further. The heating chamber 330 may be provided with a hot air removal hood, not shown in Figure 3, so that the air can be removed and, if applicable, delivered to a waste heat recovery system. Downstream of the removal of bulk material from the heating chamber 330, a heat recovery system is provided, in particular a heat exchanger 390, for example, including tube bundles or a coil traversed by an operating fluid that extracts heat from heated bulk material. ηη£7 ίη / 77Ω7 / Β / ΥΙΛΙ The operating fluid of the heat exchanger 390 may be water, for example, to produce superheated steam, CO2 or supercritical CO2, as well as air or other fluids, as necessary. In the present embodiment, the heat exchanger 390 is arranged according to a vertical drop configuration for the bulk material. The heat exchanger 390 can be realized, in preferred solutions, according to a countercurrent configuration, to improve exergetic performances. The cold bulk material, after heat exchange, may be cycled back to a lifting conveyor 360 upstream of the heating chamber 330, for example, in the case of a closed loop system for continuous generation of thermal energy. or electrical. The heat extracted from the bulk material can be used for different energy or thermal uses, at an industrial level or not. For example, it can be used for steam generation and converted into electrical energy by means of a power block. In the case of electricity generation, heat exchanger 390 can produce superheated steam or supercritical CO2, to drive a steam turbine or a CO2 turbine respectively. The same arrangement of a heat recovery system, for example, as based on the heat exchanger 390, may also be provided in other plant configurations, for example, those described above with reference to Figures 1 and 2. In particular , in case the bulk material has to undergo a specific heat treatment process, such as ore brittleness, as described above, the heat exchanger located downstream of the conveyor performs the dual function of cooling the bulk material , so that it can be transported safely and reliably for later use, and to recover its thermal energy content, which would otherwise be lost. A hot tank (not shown in the figure) may be interposed downstream of the mechanical conveyor 350 and the heat exchanger 390 to store the hot bulk material, discharged by the conveyor 350, for a certain time, according to the capacity of the hot tank. The hot tank is thermally insulated, in order to minimize heat losses to the environment during storage time. The interposition of the hot tank between the mechanical conveyor 350 and the heat exchanger 390 adds a thermal energy storage capacity to the system 300: the stored hot material can be discharged from the hot tank to the heat exchanger 390 at any time, regardless of the solar presence and the level of solar radiation, generally at night. In this way, the solar energy capture phase is decoupled from the high temperature fluid generation phase (superheated steam, supercritical CO2, hot air, etc.), so that the generation phase can occur independently of solar presence. . Generally, system 300, provided with hot tank interposition, allows the production of electricity in the absence of sun. In another preferred configuration for the production of electricity, the heat exchanger 390 can be realized by means of thermophotovoltaic panels (TPV, for its acronym in English), for a process of direct conversion of heat to electricity. . The TPV panels may also be integrated into (a portion of) the chamber 330 and the portion of the mechanical conveyor covers 350, downstream of the chamber 330, to receive heat from the hot bulk material being transported and produce electricity. Figure 4 schematically shows one embodiment of a heating chamber, denoted by 430, that can be used in any of the system designs described above. The chamber has a sloped roof or side wall 432 that defines an internal reflective or re-radiating surface 436. Solar radiation enters the chamber 430 through a side opening 435 and is reflected onto the bulk material by reflecting the surface or element 436. arranged substantially on an opposite side with respect to the opening 435. At the bottom of the chamber 430, there is a belt conveyor 450, which has a front linear length 453 and a bottom linear length 454. According to a simplified heat balance, in a possible embodiment discussed only by way of example, in a small plant size the following common size parameter can be obtained. Assuming a solar power of 8 MWt entering the chamber opening from the heliostat field, conveyor width of 2 m, conveyor speed of 5 cm / s, average material thickness on the conveyor of 4 cm, length of heating of the material below the chamber of 8 m, specific weight of the material of 1.4 t / m3, thermal efficiency of the chamber at 90%, the system may be capable of heating up to 1,000°C, starting from ambient temperature, approximately 20 t / h of material in 160 s. The present invention has so far been described with reference to preferred embodiments. It is intended that there may be other modalities that refer to the same inventive concept defined by the scope of the following claims.

Claims

1. A treatment system (100; 200; 300) for bulk solid material, wherein the treatment system (1) comprises: a mechanical conveyor (150), configured to receive the bulk solid material on a conveying surface (158) thereof and to move the material from a loading region (155) to a discharge region (156); a heating chamber (130), configured to receive solar radiation conveyed by an external optical arrangement (110), wherein a length portion (151) of the conveying surface (158) passes into or below the heating chamber (130) such that the thermal energy associated with the solar radiation is transferred to the bulk material by direct incidence or by reflection or re-radiation by internal surfaces or walls (136) of the heating chamber (130).

2. The treatment system (100; 200; 300) according to claim 1, wherein the mechanical conveyor is a belt conveyor (150) and wherein preferably the conveying surface (158) is at least partially a substantially flat surface.

3. The treatment system (100; 200; 300) according to claim 1 or 2, wherein the internal surfaces or walls (136) of the heating chamber (130) comprise at least one reflective and / or re-radiating surface configured to reflect the solar radiation entering the heating chamber (130) directly onto the length portion (151) of the mechanical conveyor (150) or onto another reflective and / or re-radiating surface of the heating chamber (130).

4. The treatment system (100; 200; 300) according to any of the preceding claims, wherein the heating chamber (130) comprises an inlet opening (135; 235) for solar radiation, preferably arranged in a side wall (131) or roof (132) thereof.

5. The treatment system (100; 200; 300) according to the preceding claim, wherein the inlet opening (135; 235) directly connects the interior of the heating chamber (130) with the outside environment, being deprived, in use, of any closing or protection means.

6. The treatment system (100; 200; 300) according to any of the preceding claims, wherein the heating chamber (130) comprises an outlet device (138), in particular a hood and / or chimney, for the outlet of gases, in particular air or CO2, from the heating chamber (130).

7. The treatment system (100; 200; 300) according to any of the preceding claims, further comprising a lifting device (160), in particular a lifting conveyor, positioned upstream of the heating chamber (130) with respect to a transport direction of the mechanical conveyor (150).

8. The treatment system (100; 200; 300) according to any of the preceding claims, further comprising a material crushing system (170) located upstream of the heating chamber (130) with respect to a transport direction of the mechanical conveyor ηη£7 ίη / 77Ω7 / B / YILI (150).

9. The treatment system (300) according to any of the preceding claims, comprising a heat recovery mechanism (390), in particular a heat exchanger, located downstream of the heating chamber (330) with respect to a transport direction of the mechanical conveyor (350).

10. The treatment system (300) according to the preceding claims, wherein the heat recovery system includes thermophotovoltaic panels.

11. The treatment system (100; 200; 300) according to any of the preceding claims, wherein the heating chamber (130) and the length portion (151) of the mechanical conveyor (150) are arranged in elevation with respect to the ground.

12. The treatment system (100; 200; 300) according to any of the preceding claims, comprising the optical system (110).

13. The treatment system (100; 200; 300) according to the preceding claim, wherein the optical system (110) comprises a plurality of reflecting elements (111) placed at ground level, preferably a field of heliostats.

14. The treatment system (200) according to claim 12 or 13, wherein the optical system (110) has a downward beam configuration, comprising one or more primary reflectors (211) arranged at ground level and one or more secondary reflectors (212) arranged at elevation, so as to carry solar radiation from above to the heating chamber (230).

15. The treatment system (100; 200; 300) according to any of the preceding claims, comprising a heated tank for storing the heated material, which is arranged directly below the heating chamber (330).

16. A heat treatment method for bulk solid material, wherein the treatment method comprises: conveying the bulk solid material over a conveying surface (158) according to a conveying route; causing a length of the conveying route to pass through or under a heating system (130), configured to receive solar radiation conveyed by an external optical system (110), such that the thermal energy associated with the solar radiation is transferred to the bulk material by direct incidence or by reflection or re-radiation by internal surfaces or walls (136) of the heating system (130).

17. The treatment method according to the preceding claim, which is a bulk material calcination system, in particular a limestone calcination system.

18. The treatment method according to claim 16, which is a bulk material embrittlement system.

19. The treatment method according to any of claims 16 to 18, which is a thermal or electrical power generation system.

20. The treatment method according to any of claims 16 to 19, using a treatment system (100; 200; 300) according to any of claims 1 to 15.