FR3007829A1 - HEATING METHOD WITH GENERATION AND COMBUSTION OF SYNGAZ AND INSTALLATION FOR ITS IMPLEMENTATION - Google Patents

Abstract

A method of heating by syngas combustion in a furnace (300), wherein the syngas (110) is produced in a synthesis reactor (100), the flue gases (301) generated by combustion are removed, recovered from the thermal energy of the fumes (301) by heat exchange with a heat transfer fluid (602, 401), the heated heat transfer fluid (402) being then introduced into the synthesis reactor (100) so as to use the thermal energy recovered for the production syngas (110).

Description

The present invention relates to industrial combustion heating processes. These industrial heating processes are, for example: vitrification, such as, for example, glass melting, metal melting, such as, for example, the second melting of metals, and reheating of metals. The heating process can be continuous or discontinuous. Industrial heating processes generally use fossil fuels such as natural gas, fuel oil and coal. The combustion may be an air combustion or combustion with an oxidant having an oxygen content higher than that of air, such as oxygen-enriched air or substantially pure oxygen. Combustion with an oxidant richer in oxygen than air is known as oxy-combustion.

Oxy-combustion has many advantages over air combustion, also known as aerocombustion: - reduction of NOx emissions, - reduction of the volume of fumes generated, - reduction of fuel consumption and thus also emissions of CO2 of fossil origin. This reduction in fuel consumption is, however, limited when oxycombustion is compared with aerocombustion processes that allow the combustion air to be preheated by heat recovery from the fumes generated by the combustion. To improve the economic performance of oxy-combustion, it is sought to further reduce the fuel consumption by: - the type and design of the oxy-fuel burner, - the design of the combustion chamber allowing in particular a lowering of the fuel consumption. temperature of the fumes at the furnace outlet, a reduction of the thermal losses, etc., the preheating of the oxidant and / or the fuel by heat recovery of the fumes generated. However these techniques cap relatively quickly and the gap between the most efficient oxy-combustion process and the most efficient preheated air combustion method remains weak. This restricts the market for oxy-combustion in industrial heating processes. US-A-20090011290 discloses a thermochemical recovery process. According to this method, a part of the flue gases from the combustion furnace is used as a reagent for the reforming of a fuel. The reformed fuel is burned in the combustion furnace. Before being used as a reforming reagent, the fumes from the furnace are used as heat transfer fluid for the preheating of the combustion oxidant and the reformed fuel in recuperators upstream of their introduction into the combustion furnace.

Such use of fumes for the preheating of fuel and oxidizer in recuperators is possible in an industrial installation only when the fumes are poor in pollutants (condensables) likely to be deposited on the walls of the recuperators.

EP-A-1143200 discloses a method of combustion in an oven, such as a glass melting furnace, in which synthetic products resulting from an endothermic chemical reaction, such as synthesis gas or syngas, are used as fuel. . Production of said synthesis products takes place in two regenerators which operate alternately and which are heated by fumes coming from a source other than the furnace in which the products of synthesis are used as fuel. Indeed, fumes from a glass melting furnace are highly charged condensable materials. Said other source of fumes may be another facility at the industrial site that produces relatively clean smoke or an installation for the combustion of a fuel with air specifically intended for the production of hot fumes for heating the two regenerators . The first case can only be envisaged if there is an installation producing relatively clean fumes near the furnace and in this case, the implementation of the combustion process in the furnace will depend on the simultaneous operation of this other installation. The second case involves the construction and operation of an additional combustion plant, which is particularly expensive. In any case, the method described in EP-A-1143200 does not significantly improve the energy balance of the furnace insofar as said method depends on an additional external thermal energy source.

The present invention is made in the context of techniques for reducing fuel consumption and reducing fossil CO2 emissions in high temperature industrial heating processes. It aims to at least partially overcome the problems associated with known methods described above.

The present invention particularly covers a combustion heating process. According to this method, syngas is produced in a synthesis reactor by endothermic chemical reaction between reagents. These reagents include, on the one hand, a carbonaceous material and, on the other hand, water vapor and / or CO2. Fuel is burned with oxidant in an oven, at least a portion of the fuel being syngas produced as described above. This combustion generates heat and smoke in the oven. The fumes from the furnace are often charged with dust and / or volatile substances that can condense at temperatures in the so-called "range of condensation" range, generally from 600 ° C. to 800 ° C. and in particular from 600 ° C. to 700 ° C. ° C. The fumes are removed from the furnace and thermal energy is recovered from the flue gases evacuated by heat exchange with a coolant. According to the invention, during this step, the thermal energy of the fumes discharged from the furnace is recovered by heat exchange with a heat-transfer fluid so as to obtain a heated heat-transfer fluid. At least a part of said heated heat transfer fluid is then introduced into the synthesis reactor and used as a thermal energy source for the endothermic chemical reaction. The invention thus makes it possible to use at least a portion of the energy recovered for synthesis. of syngas.

According to a preferred embodiment, the thermal energy recovery step comprises at least a first recovery phase at a first flue gas temperature range and a second recovery phase at a second temperature range. At least a portion of the heat transfer fluid is used as a source of thermal energy for the endothermic chemical process.

The first temperature range is chosen so that there is no condensation of volatile substances present in the fumes at these temperatures.

Therefore, when the fumes from the furnace are charged with volatile substances as defined above, the first range of temperature is chosen a range greater than the range of condensation. Between the first and the second recovery phase, the fumes are subjected to a cleaning which involves the elimination of dust and / or volatile substances that can condense at the temperatures of the second temperature range. When the fumes contain volatile substances as defined above, the cleaning step allows an efficient recovery of thermal energy fumes in the second temperature range even if this second range covers or is less than the range of condensation.

The present invention thus allows an efficient and practical recovery of thermal energy present in the fumes discharged from the furnace. Dust and / or condensable substances can be produced by burning in the furnace, especially when syngas is not the only fuel burned. The dust and / or condensable substances present in the flue gas may also have other origins, such as, for example, entrainment or volatilization of part of the charge to be heated or melted in the oven. According to one embodiment, the synthesis reactor comprises a first chamber, said reaction chamber and in which the endothermic chemical reaction takes place and a second chamber, said heating chamber which contains heated heat transfer fluid.

In the method, thermal energy recovered from the fumes is transmitted from the heating chamber to the reaction chamber by heat exchange with the heat-transfer fluid, and this through a heat exchange wall separating the enclosure of reaction of the heating chamber.

The carbonaceous material of the reactants of the endothermic chemical reaction is advantageously a gaseous carbonaceous material, preferably natural gas or methane. It is also possible to produce syngas in two synthesis reactors operating alternately.

According to a preferred embodiment, at least part or all of the fuel is burned in the oven with an oxygen-rich oxidant. Oxygen-rich oxidant is an oxidant having an oxygen content greater than the oxygen content of the air. Preferably, the oxygen-rich oxidant has an oxygen content of at least 80% vol, more preferably at least 90% vol and more preferably at least 95% vol, or at least 99% vol, and up to 100% vol. Thus, the process according to the invention may be a process using oxygen-enriched air as oxidant; a process with oxyboosting, that is to say a process in which less than 25% of the heat generated by combustion of the fuel in the furnace is generated by combustion with an oxidant having an oxygen content of at least 80% flight ; a mixed aero-oxy combustion process, that is to say a process in which at least 25% of the heat generated by the combustion of the fuel is generated by combustion in the furnace with an oxidant having an oxygen content of at least 80% vol, the remainder being generated by combustion with air as oxidant; or an all-oxy process, ie a process in which all the heat generated by combustion in the furnace is generated with an oxidant having an oxygen content of at least 80% vol. The heat generated in the furnace is usefully used to heat and / or melt a charge present in the furnace. As already mentioned, the invention is particularly interesting for processes in which the fumes discharged from the oven comprise dust and / or volatile substances from the load. The oven may thus be a vitrification furnace, such as, for example, a glass melting furnace comprising at least one of the following structures: a melting chamber, a refining chamber, a melting-refining chamber and a glass feeder . The melting chamber may also be a melting-melting chamber incorporating a melting zone and a refining zone. The oven may also be a metal smelting furnace, such as for example a second metal smelting furnace such as aluminum, lead, etc. The endothermic chemical reaction is typically SMR (Steam Methane Reforming) or DMR (Dry Methane Reforming). In one embodiment, at least a portion of the cleaned fumes obtained in the recovery step is used as a reagent in the endothermic chemical process of the syngase production step. Indeed, these cleaned fumes contain CO2 and water vapor and can therefore be used as a reagent in the endothermic chemical reaction. When the process comprises a second recovery phase, the thermal energy of the fumes is advantageously recovered, at least in the first stage of the recovery stage and preferably in the first and second phases of the recovery stage. by heat exchange with a coolant. The heat exchange between the fumes and the coolant is advantageously carried out by means of one or more recuperators. Thus, it will be usefully used a first recuperator for the heat exchange between the flue gas and the coolant in the first phase of the recovery step and a second recuperator for this heat exchange in the second phase of this recovery step. The heat transfer fluid is preferably heated partially by heat exchange with the flue gases in the second stage of recovery of the stage, that is to say at the second range of flue gas temperatures. The heat-transfer fluid partially heated in this second recovery phase is then heated by heat exchange with the flue gas in the first recovery phase, that is to say at the first flue gas temperature range that is greater than the second range. The preferred heat transfer fluids are air, nitrogen and steam.

When the heat transfer fluid is steam, it is possible to use at least a portion of the heat transfer fluid heated in the recovery step, that is to say the vapor thus heated in the recovery step, as reagent in the endothermic chemical process for the production of syngas. The coolant can be used in an open circuit, for example with air as heat transfer fluid or when the coolant is steam which is then used as a reagent. The coolant can also be used in a closed circuit. In this case, at least a portion of the coolant is returned to the recovery step after its use as a source of heat energy in the endothermic chemical reaction. When the thermal energy recovered from the exhaust fumes is higher than the thermal energy consumed by the endothermic chemical reaction, the surplus of thermal energy recovered can be used for other purposes, in parallel with or after the reaction. endothermic chemical / synthesis reactor.

Thus, it is possible to use a portion of the recovered thermal energy to preheat the carbonaceous material prior to its use as a reagent in the endothermic chemical reaction. Another possibility is to use a portion of the thermal energy recovered to generate and / or superheat steam before it is used as a reagent in the endothermic chemical reaction and / or to use a portion of the thermal energy recovered to preheat CO2 before use as a reagent in the endothermic chemical reaction. Part of the recovered thermal energy can also be used to preheat the oxidant upstream of its use for fuel combustion. Advantageously, water is extracted from the syngas by condensation before being used as fuel in the furnace. The present invention also relates to a heating installation adapted for carrying out the method according to any one of the embodiments described above. Such an installation comprises in particular the following equipment: a syngas synthesis reactor, an oven equipped with one or more burners for the combustion of a fuel with an oxidant and at least one flue gas outlet, a recovery installation thermal energy by heat exchange between the fumes and a heat transfer fluid and having a heat transfer fluid outlet. According to the invention, said equipment is connected so as to allow the implementation of the method according to the invention. This implies in particular that: the synthesis reactor is connected to the furnace so as to allow the supply of syngas produced in the reactor as fuel to at least one furnace burner; - The output of the furnace fumes is connected to the thermal energy recovery plant so as to allow the supply of fumes from the furnace to said recovery facility. - The output of the heated heat transfer fluid of the thermal energy recovery system is connected to the syngas synthesis reactor so as to allow the supply of at least a portion of the heated heat transfer fluid.

According to a preferred embodiment, the recovery installation comprises a first heat energy recovery equipment and a second heat energy recovery equipment. The first and second equipment are preferably heat exchangers as described above. The outlet of the furnace fumes is then connected to the first thermal energy recovery equipment so as to allow the supply of fumes from the furnace to said first equipment. The first equipment is advantageously connected to a flue gas cleaning system so as to allow the supply of fumes to the cleaning installation and the cleaning installation is in turn connected to the second heat energy recovery equipment so as to allow the supply of cleaned fumes from the cleaning installation to said second recovery equipment. The thermal energy recovery installation preferably comprises at least one heat exchanger which allows the thermal energy recovery of the flue gases by heat exchange with a heat transfer fluid. The installation according to the invention can be adapted for the implementation of any one of the embodiments of the heating method according to the invention. Thus, for the combustion of a fuel with an oxidizer, the furnace is not only connected to one or more fuel sources, and at least to the synthesis reactor as a source of syngas as a fuel, but also to one or several sources of oxidant. In a preferred embodiment, the furnace is connected to at least one source of an oxidant having an oxygen content greater than the oxygen content of the air. The oxidant is provided as an oxidant to at least one furnace burner. In a useful manner, said oxidant has an oxygen content greater than 80% vol 02, preferably 90% vol 02, more preferably greater than 95% vol 02, and more preferably greater than 99% vol 02. L' Comparative example below describes in more detail the present invention and its advantages, reference being made to the figure which is a schematic representation of a method / a heating system according to the invention using natural gas as carbonaceous material for syngaz synthesis by SMR. The figure illustrates more particularly such a method / such an installation according to the invention which is particularly suitable for heating a glass melting furnace. According to the example, the syngas is synthesized in the synthesis reactor 100 by endothermic catalytic reaction between preheated natural gas 101 and steam 102, these two reactants having a reactor inlet temperature 100 of at least 300 ° C. C, more particularly 325 ° C. The syngas 110 generated by catalytic SMIR in the reactor 100 and composed mainly of H2 and CO is then sent to the furnace 300 (not shown) in which the syngas 110 is used as fuel. In the furnace 300, the thermal energy generated by this combustion is used for the melting of batch materials. Table 1 gives the composition and the ICP (Lower Calorific Value) of the syngas thus generated from the natural gas and compares the 1 Nm3 PCI of the generated syngas with the PCI of the 0.209 Nm3 of natural gas (CH4) consumed for the production of 1 Nm3 of syngas.

Syngaz composition CH4 0.25% H2O 13.28% H2 65.78% CO 16.98% CO2 3.71% ICP 2229.04 kcal / Nm3 * LCI of 1 Nm3 2229.04 Kcal A syngas energy - natural gas 25% natural gas PCI 8534 kcal / Nm3 * PCI of 0.209 Nm3 1784 Kcal Table 1 The syngas 110 generated in the reactor 100 can be directly directed to the oven 300 or, as in the illustrated case, can first undergo a step of at least partial condensation of the steam contained in the syngas before use as a fuel. This makes it possible to increase the syngas's PCI and to control (reduce) the humidity in the furnace atmosphere. This condensation takes place in the condenser 200. The recovered water 111 may, for example, be used for the production of the vapor 102 upstream of the reactor 100. Preferably, the water condensation energy is recovered. It is thus possible to use cooling water 202 for condensing the steam in condenser 200, and to use water, heated vapor 203 coming from condenser 200 for the production of steam 102 upstream of reactor 100 or more generally, as a source of thermal energy. The dry syngas 210 from the condenser 200 is then directed to the oven 300 where the syngas dry 210 is used as fuel.

In the illustrated case, the syngas is the only fuel used in furnace 300. The furnace is an oxy-free furnace, that is, the only oxidant used in the furnace is an oxidant with an oxygen content of 80. % vol to 100% vol. In another embodiment, the syngas can be used in combination with another fuel. In a similar manner, the furnace can also combine, on the one hand, the oxy-combustion as defined above with, on the other hand, an oxidizer that is less rich in oxygen, such as, for example, air. The fumes 301 generated by the combustion are removed from the furnace 300. They are at an elevated temperature, of the order of 1250 ° C. in the example illustrated. They are first sent to a first recuperator 400, said high temperature recuperator. In this first recuperator 400, the fumes are used to heat a coolant (air in the case illustrated). At least a portion 404 of the heat transfer fluid 402 thus heated is sent to the reactor 100 and is used as energy source for the endothermic synthesis syngase synthesis reaction.

Another portion 405 of the heat transfer fluid 402 is directed to other heat-consuming equipment. In the case illustrated, the air used as coolant is heated to a temperature of 800 ° C in the first recuperator 400. The first recuperator 400 is operated so that the volatile substances present in the fumes 301 do not condense at inside said first recuperator. In the illustrated case, the fumes 403 are discharged from the first recuperator at a temperature of 800 ° C. When the fumes discharged from the furnace 300 are charged with particles (dust), care is taken to maintain the flow velocity of said fumes inside the first recuperator 400 at a sufficiently high level to prevent an accumulation of particles inside said first recuperator 400.

These temperate fumes 403 are sent to a cleaning installation 500. In this installation, said fumes 403 are subjected to a cleaning treatment, that is to say to a dust removal treatment and / or to a step d elimination of volatile condensable substances. The cleaning processes used are chosen so as to avoid excessive cooling of the fumes during the cleaning treatment so as to limit losses of thermal energy during cleaning. For example, a cleaning using high temperature filters will be chosen. The cleaned fumes 501 are directed to a second recuperator 600, said low temperature recuperator.

In this second recuperator, the residual energy of the cleaned fumes 501 is recovered by heat exchange with a coolant 602. The cooled fumes 601 are then directed to an extractor 700 before being released into the atmosphere or to be treated. and captured.

By cleaning the fumes in the cleaning installation, a cleaning step in which said fumes are removed volatile substances that can condense at flue gas temperatures in the low temperature recuperator 600, it is possible to recover the residual thermal energy of the fumes. The present invention thus allows optimal recovery of the heat present in the flue gases 301 at the outlet of the furnace 300. In the illustrated case, the heat transfer fluid 602 for the second recuperator 600 is of the same type. compressed air supplied by the fan 800. It is possible to use two different heat transfer fluids 401, 602 for the first and the second recuperator 400, 600 and to use the two heat transfer fluids thus heated 402, 603 as a source of thermal energy. in the process according to the invention, for example in the synthesis reactor 100. In the case illustrated, the same heat transfer fluid is used in the first and the second recuperator 400, 600. The compressed air 602 supplied by the fan 800 is first sent to the low temperature recuperator 600. In said recuperator 600, the air is heated by heat exchange with the cleaned fumes 501 from the cleaning installation 500. The air (coolant) thus heated 603, which in the illustrated case is at a temperature of the order of 500 ° C, is then introduced in the high temperature recuperator 400. In the high temperature recuperator 400, the heated air from the first low temperature recuperator 600 is again heated by heat exchange with the uncleaned fumes 301 from the furnace 300. In the case illustrated, the The hot air (heat transfer fluid) 402 leaves the high temperature recuperator at about 800 ° C. In order to allow better control of the flue gas temperature at the inlet of the first recuperator 400 and / or the cleaning installation 500 (for example, for reasons of thermal resistance of the materials and to optimize cleaning), pipes are provided for the controlled flow injection of a tempered gas 901, 902 respectively into the flue gas 301 upstream of the first recuperator and / or into the flue gas 403 upstream of the cleaning installation 500. The tempered gas can, for example, be ambient air and / or a part of the coolant 107 at the outlet of the reactor 100 and / or the recuperators / exchangers 10, 20, or 30. The residual thermal energy present in the heat transfer fluid 103 to the outlet of the reactor 100 is advantageously used for the preheating of the reagents used in the process according to the invention. Thus, in the illustrated case, a first portion 104 of the heat transfer fluid is directed to the recuperator / boiler 10 for the generation of the steam 102 used for the syngas synthesis. A second portion 105 of the coolant is directed to a recuperator 20 for preheating the carbonaceous material (natural gas) for the syngaz synthesis reaction.

A third portion 106 of heat transfer fluid is directed to a second recuperator 30 for preheating the oxidant (oxygen) before introduction into the furnace. It is also possible to use at least a portion of the heat transfer fluid 103 from the reactor 100 for preheating the syngas 210 upstream of the furnace 300. If a second fuel is also burned in the furnace 300, at least a portion of the heat transfer fluid 103 can be used for preheating the second fuel and / or syngas 210 upstream of the furnace 300. For example, it is possible to use a portion of the natural gas preheated in the exchanger 20 as fuel in the furnace 300. general to recover and use a maximum of the thermal energy present in the fumes 301 at the outlet of the oven.

In the illustrated case, the heat transfer fluid circulates in closed circuit, that is to say that the heat transfer fluid from the reactor 100 is reused as heat transfer fluid 602 in the recuperators 600 and 400. It is also possible to use the fluid coolant in open circuit. The energy efficiency of the process according to the invention applied to a glass melting furnace was compared with the energy efficiency of the most effective known processes for glass melting. In Tables 2 to 3 below: - AA1: relates to a glass melting furnace according to the prior art using the combustion of natural gas with the oxidizer of the preheated air by means of new regenerators; - AA2: relates to a glass melting furnace according to the prior art using the combustion of natural gas with non-preheated oxygen as oxidant; - AA3: relates to a glass melting furnace according to the prior art using the combustion of natural gas with oxygen preheated using the technology developed by the applicant as described in EP-A0872690; Inv 1 relates to the implementation of the process according to the invention in a glass melting furnace with combustion of the syngas generated as the only fuel in the furnace with oxygen preheated as an oxidant. Table 2 gives a comparison between the process according to the invention (ex 1) and the three processes according to the prior art (AA1 to AA3) for a technical addition or melting process identical to that carried out in example AA1 with a consumption of natural gas, used as fuel in the furnace, of 100 Nm3 / h. Table 3 gives a comparison between the process according to the invention and the three processes according to the prior art for identical extraction of the glass melting furnace. AA 1 AA2 AA3 Inv 1 Fuel: Natural gas Nm3 / h 100 102 93 Combustible temperature ° C 25 25 450 450 Fuel: Syngaz Nm3 / h 350 Overall consumption of natural gas (combustion 100 102 93 73 and / or syngas production) Nm3 / h A Overall consumption of natural gas compared to AA2 -8% -28% A Total natural gas compared to AA1 2% -7% -27% Combustion air Nm3 / h 1000 Combustion air temperature ° C 1200 Oxygen (100% ) Nm3 / h 204 188 146 Combustion oxygen temperature ° C 25 550 550 Furnace energy kW 1462 1008 989 1039 Enthalpies exhausted with flue gas kW 694 240 221 271 Thermal input to the melting process kW 768 768 768 768 Table 215 Example AA 1 AA2 AA3 Inv 1 Fuel: natural gas Nm3 / h 900 828 762 Fuel: syngas Nm3 / h 2852 Combustible temperature ° C 25 25 450 450 Overall consumption of natural gas (combustion 900 828 762 597 and / or syngas production) Nm3 / h A Overall consumption of natural gas by -8% -15% -34% compared to AA1 Combustion flow: air Nm3 / h 8900 Combustible flow rate: oxygen (100%) Nm3 / h 1630 1498 1155 Combustion temperature ° C 1200 25 550 550 Combustion fume flow rate Nm3 / h 10918 3326 3129 3744 Fume temperature at the end of the oven ° C 1450 1450 1450 1450 Table 35

Claims (15)

REVENDICATIONS1. A method of combustion heating, wherein (a) syngas (110) is produced in a synthesis reactor (100) by endothermic chemical reaction between reagents including (i) a carbonaceous material and (ii) (102) and / or CO2, (b) burning fuel with oxidant in a furnace (300) with heat generation and fumes in the furnace (300), at least a portion of the fuel being the syngas (110, 210) produced in step (a) (c) discharges the fumes (301) from the furnace, (d) recovering thermal energy from the fumes (301) discharged from the furnace (300), at least a part of the thermal energy recovered from the fumes (301) being consumed in the synthesis reactor (100) by the endothermic chemical reaction of step (a), characterized in that in step (d), thermal energy is recovered from the fumes discharged from the furnace (300) by heat exchange with a coolant (602, 401) and in that ns a portion of the heated heat transfer fluid (402) is introduced into the synthesis reactor (100) and used as a source of thermal energy for the endothermic chemical reaction. 2. The method of claim 1, wherein the synthesis reactor (100) comprises a reaction chamber in which the endothermic chemical reaction takes place and a heating chamber containing heated heat transfer fluid and in which thermal energy recovered from fumes (301) is transmitted from the heating chamber to the reaction chamber by exchange through a heat exchange wall separating the reaction chamber from the heating chamber. 3. The method of claim 1 or 2, wherein the heat transfer fluid is selected from air, nitrogen and steam (102). The method of claim 3, wherein the heat transfer fluid is steam (102) and at least a portion of the heat transfer fluid (402) heated in the recovery step is used as a reagent in the endothermic chemical process. 5. Process according to any one of the preceding claims, in which at least a portion of the coolant is returned to the recovery step after its use as a source of thermal energy in the endothermic chemical reaction. 6. Heating process according to one of the preceding claims, wherein the carbon material of the reagents is a gaseous carbon material, preferably natural gas or methane. 7. A method of heating according to any one of the preceding claims, wherein is burned in the oven (300) at least a portion and preferably all of the fuel with oxygen-rich oxidant. The process of any one of the preceding claims, wherein the heat generated in the furnace (300) is used to heat a charge present in the furnace (300). The process of claim 8, wherein the furnace (300) is a vitrification furnace or a metal smelting furnace. 10. Process according to one of the preceding claims, wherein the endothermic chemical reaction is SMR or DMR. 11. Process according to any one of the preceding claims, in which the fumes (301) generated in the oven (300) are loaded with dust and / or volatile substances that can condense at temperatures between 600 ° C. and 800 ° C. and wherein: the recovery step comprises at least a first recovery phase at a first flue gas temperature range and a second recovery phase at a second flue gas temperature range lower than the first flange; there is no condensation of volatile substances present in the fumes at the temperatures of the first temperature range, and - the fumes are subjected to a cleaning between the first and the second recovery phase, said cleaning comprising the elimination of dust and / or or volatile substances present in the fumes that are likely to condense at the temperatures of the second temperature range, and in which, at least in the first phase of the recovery stage and preferably in the first and second phases of the recovery stage, the thermal energy of the fumes is recovered by heat exchange with a coolant (602, 401). The process of claim 11, wherein at least a portion of the cleaned fumes (501, 601) obtained in the recovery step is used as a reagent in the endothermic chemical process for the production of syngas. 13. A method according to one of claims 11 and 12, wherein the heat transfer fluid (602) is heated partially by heat exchange with the fumes (501) in the second recovery phase and wherein the heat-exchanged heat-exchanged medium is heated. (603, 401) in the first phase of recovery by heat exchange with the fumes (301) in the first recovery phase. 14. A process according to any one of the preceding claims, wherein a portion of the recovered thermal energy is used at least one, and preferably more than one, of the following: a) to preheat the carbonaceous material prior to its use as a reagent in the endothermic chemical reaction; b) for generating and / or superheating steam prior to its use as a reagent in the endothermic chemical reaction; C) for preheating CO2 prior to use as a reagent in the endothermic chemical reaction; d) to preheat the oxidant upstream of its use for fuel combustion. 30 15. A process according to any one of the preceding claims wherein syngas is condensed from water prior to use as fuel in the furnace (300).