Direct-fired heating method and facility for implementing same

Patent metadata

Field	Value
Publication number	US-10359191-B2
Application number	US-201414392225-A
Country	US
Kind code	B2
Filing date	Jun 26, 2014
Priority date	Jun 26, 2013
Publication date	Jul 23, 2019
Grant date	Jul 23, 2019

Abstract

The invention relates to a direct-fired heating method and to a facility for implementing same, According to said method, a load is heated in a furnace with heat generated by burning fuel with an oxidant; the smoke generated is evacuated from the furnace, the evacuated smoke containing residual heat energy; residual heat energy is recovered from the evacuated smoke and introduced into a synthesis reactor wherein syngas is produced; and at least part of the syngas is burned in the furnace in order to heat the load.

First claim

What is claimed is:

1. A direct-fired heating process, in which process:
(a) a feedstock to be heated is introduced into a furnace, wherein the furnace is a vitrification furnace or a furnace for the reheating or melting of metals,
(b) fuel is burnt with the oxidant with generation of heat and flue gases in the furnace,
(c) the feedstock is heated in the furnace with the heat generated,
(d) the heated feedstock and the flue gases generated are discharged from the furnace, the discharged flue gases containing residual thermal energy,
(e) syngas is produced in a synthesis reactor by an endothermic chemical reaction between reactants including (i) a carbon-based material and (ii) steam and/or CO 2 , the synthesis reactor comprising at least one reaction region into which the reactants are introduced and in which the endothermic chemical reaction takes place and from where the syngas produced is extracted:

characterized in that:
residual thermal energy is recovered from the flue gases discharged from the furnace, at least a portion of the residual thermal energy thus recovered being introduced into the synthesis reactor and consumed by the endothermic chemical reaction of stage (e), and
at least a portion of the fuel burnt in the furnace in stage (b) is syngas produced in stage (e).

2. The process of claim 1 , wherein the synthesis reactor also comprises at least one heating chamber into which said at least a portion of the recovered residual thermal energy is introduced, said at least one heating chamber being positioned, with respect to the at least one reaction region, so that recovered residual thermal energy is transferred from the at least one heating chamber to the endothermic chemical reaction in the at least one reaction region through at least one separating wall between the at least one heating chamber and the at least one reaction region.

3. The process of claim 2 , wherein each reaction region is surrounded by a neighboring heating chamber or housed between two neighboring heating chambers.

4. The process of claim 2 , wherein the synthesis reactor has a lamellar structure comprising an alternation of heating chambers and reaction regions, said heating chambers and reaction regions being situated between two successive plates.

5. The process of claim 1 , wherein residual thermal energy is recovered from the discharged flue gases by heat exchange between the discharged flue gases and a heat-exchange fluid so as to obtain moderated flue gases and heated heat-exchange fluid containing the recovered residual thermal energy, at least a portion of the heated heat-exchange fluid being introduced into the synthesis reactor in order to provide the at least a portion of the recovered residual thermal energy to the endothermic chemical reaction of stage (e).

6. The process of claim 2 , wherein residual thermal energy is recovered from the discharged flue gases by heat exchange between the discharged flue gases and a heat-exchange fluid so as to obtain moderated flue gases and heated heat-exchange fluid containing the recovered residual thermal energy, at least a portion of the heated heat-exchange fluid being introduced into the at least one heating chamber in order to provide the at least a portion of the recovered residual thermal energy to the endothermic chemical reaction of stage (e) through the at least one separating wall.

7. The process of claim 1 , wherein the discharged flue gases are laden with dust and/or volatile substances capable of condensing at temperatures between 600° C. and 800° C. and in which the stage of recovery of residual thermal energy from the flue gases discharged from the furnace comprises at least a first phase of recovery at a first range of temperatures of the flue gases and a second phase of recovery at a second range of temperatures of the flue gases which is below the first range and in which:
at the temperatures of the first range of temperatures, there is no condensation of the volatile substances present in the flue gases, and
the flue gases are subjected to a cleaning operation between the first and the second phase of recovery, said cleaning operation comprising the removal of dust and/or of volatile substances which are capable of condensing at the temperatures of the second range of temperatures.

8. The process of claim 7 , wherein a heat-exchange fluid is partially heated by heat exchange with the flue gases in the second phase of recovery and in which the heat-exchange fluid partially heated in the first phase of recovery is heated by heat exchange with the flue gases in the first phase of recovery.

9. The process of claim 8 , wherein the heat-exchange fluid is chosen from air, nitrogen and steam.

10. The heating process of claim 1 , wherein at least a portion and preferably all of the fuel is burnt in the furnace with an oxygen-rich oxidant.

11. The process of claim 8 , wherein the furnace is a vitrification furnace or a furnace for the melting of metals.

12. The process of claim 1 , wherein the endothermic chemical reaction is SMR or DMR or a mixture of the two.

13. The process of claim 1 , wherein a portion of the thermal energy recovered from the discharged flue gases is used for at least one of the following purposes:
a) for preheating the carbon-based material before it is used as reactant in the endothermic chemical reaction;
b) for generating and/or superheating steam before it is used as reactant in the endothermic chemical reaction;
c) for preheating CO 2 before it is used as reactant in the endothermic chemical reaction;
d) for preheating the oxidant upstream of its use in the combustion of the fuel.

14. The process of claim 1 , wherein water is extracted from the syngas by condensation before it is used as fuel in the furnace.

15. A heating plant suitable for the implementation of the process of claim 1 , said plant comprising:
a furnace provided with an inlet for a feedstock to be heated, with an outlet for the heated feedstock, with one or more burners for the combustion of a fuel with an oxidant and the generation of heat for heating the feedstock, and with at least one outlet for flue gases,
a plant for the recovery of thermal energy by heat exchange between the discharged flue gases and the heat-exchange fluid and comprising an outlet for heated heat-exchange fluid, and
a reactor for the synthesis of syngas,

characterized in that:
the synthesis reactor is connected to the furnace so as to enable the provision of syngas produced in the reactor as fuel to at least one burner of the furnace;
the outlet for the flue gases from the furnace is connected to the plant for the recovery of thermal energy so as to enable the provision of flue gases resulting from the furnace to said recovery plant,
the outlet for the heated heat-exchange fluid from the plant for the recovery of thermal energy is connected to the reactor for the synthesis of syngas so as to enable the provision of at least a portion of the heated heat-exchange fluid to the synthesis reactor.

Assignees

• Air Liquide

Inventors

• Beaudoin Philippe
• Del-Gallo Pascal
• Flin Matthieu

Classifications

• C10J2300/164

  with conversion of synthesis gas · CPC title

• Y02E20/12

  Heat utilisation in combustion or incineration of waste · CPC title

• F23G5/14

  including secondary combustion · CPC title

• C10J2300/0976

  as steam · CPC title

• Y02P20/129

  Energy recovery, e.g. by cogeneration, H2recovery or pressure recovery turbines · CPC title