LU83085A1 - METHOD FOR PRODUCING ENERGY FROM COAL AND INSTALLATION THEREFOR - Google Patents

Description

The. 'MÎst-L -i i ’·. „'‘ -Fit: gold. c '; .cxr: .s nn improved ocelé of energy production, in particular electrical energy, in which the energy source consists of coal (coal). It also extends to an installation suitable for the implementation of this process.

The recent trend for electric power production on an industrial scale is "to use coal in open or closed thermal cycles using gas turbines, as a result of the good thermal efficiency of these cycles. However, the dedusting of gases at high temperature, which is necessary to avoid too rapid wear of the turbine, appeared to be particularly difficult to carry out effectively. Indeed, the filters which can be used are quickly destroyed at high temperature. It has therefore been proposed to use heated air cycles in fluidized beds of solid fuel. These techniques have however caused difficulties due to the risk of rapid destruction of these tubes located in the fluidized bed.

The present invention aims to provide improvements to a method of producing energy, by ", i in particular electrical energy, avoiding the drawbacks Γ of prior art methods, jt i According to the invention, coal sprayed suddenly

I, pyrolysis at a temperature of the order of 500 ° C to 1200 ° C

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| in a pyrolysis oven, followed by fractionation j, ‘of a solid phase consisting of carbon particles I having the appearance of coke and of a volatile phase consisting of a mixture of combustible gases; after condensation on the king: .s partielle partial £ of the liquefiable constituents of the volatile phase, t

If b the non-condensed caz are supplied to the

Ij. combustion of a gas turbine to burn with air from a compressor producing combustion gases which are expanded in the turbine after which the exhaust gases, still under slight pressure, are conveyed to at least one bed combustion chamber. j | fluidized which is also supplied with particles of r carbon from the pyrolysis oven, with air supply! of additional combustion with a view to causing an 11 ji combustion serving to heat steam intended for i 3 I a steam turbine, i I The exhaust gases coming from the gas turbine I l therefore undergo post-combustion in the fluidized-bed combustion chamber il ji similar to post-j | combustion of conventional combined cycles with natural gas i 1 I; i g for example.

g If more than one • I is used; i i; i | combustion chamber with a fluidized bed, said chambers can be arranged in series or in parallel.

\ i | According to a particularly advantageous operating variant, steam is injected into the oven ΐ || pyrolysis to produce an additional amount II; !, volatile gases which are added to the gases coming from the pyrolysis proper, starting from the particles of this carbon I formed during the pyrolysis, according to the reaction: I C + h2o - = * CO + h2

Ipar a reaction called hydropyrolysis.

This operating variant is of certain interest because it contributes to a specific energy supply g in the gas turbine, the thermal efficiency of which is well known. The use of a hydropyrolysis reaction i j.

is particularly re-’vvv-'a: 'der when using coal with a low volatile content.

Another operating variant of the invention consists in preheating the air of the compressor of the gas turbine and / or the air injected into the fluidized bed using the fumes coming from the fluidized bed combustion chamber, after heating of the steam intended to drive the steam turbine.

The liquefiable constituents of the volatile phase originating from the pyrolysis oven can be, after condensation and separation, used in the process of the invention, for example by injecting them into one of the motive power production cycles. These liquefiable constituents are, however, preferably used for other purposes, either as fuel or as raw materials for organic syntheses.

According to the invention, it is possible to temporarily store the non-condensed combustible gases and the carbon produced during the pyrolysis or the hydro-pyrolysis, thus creating a power station with variable charge according to the energy needs of the moment.

Transiently, according to the invention, it may be advantageous to use the gas turbine without producing a driving force, the exhaust gases then undergoing, instead of post-combustion, almost complete combustion in the or the fluidized bed combustion chambers.

The invention also relates to an installation for practicing the described method consisting of a pyrolysis furnace fed with pulverized coal, "· Y",. R "r-" fl {'· - ·' ', tv. 4 - A - · * '-i .... i,. . * · W · v -: * · f · - - 'i *' "· ^ - £ separation of particulates» 5 s carbon these volatile materials which are brought by a circulation fan in a installation of condensation making it possible to separate the liquefiable fraction, a gas turbine supplied with the non-condensable gases coming from the condensation installation and at least one combustion chamber with a fluidized bed supplied by the exhaust gases of the gas turbine and by carbon particles from pyrolysis producing · superheated steam for driving a steam turbine.

Storage facilities consisting of a gasometer and a material storage chamber! solids allow to store gases respectively! condensables and carbon particles.

Advantageously, the pyrolysis oven is; equipped with a steam supply from a boiler which can be that of the fluidized bed) in order to carry out a hydropyrolysis reaction.

The additional equipment of the installation is well known to those skilled in the art and does not require any additional description.

The main advantages and characteristics of the invention are essentially: S - the use of a combined cycle for combustion; coal from gasification or liquefaction s,. -t.

paruelxe; the possibility of using under the best conditions, that is to say in a fluidized bed, solid residues of carbon having the appearance of coke or semi-coke, in one or more stages of combustion by recourse to one or fj: several combustion chambers with a fluidized bed, arranged * ~ (an sSrip nn e "r, rcar-s 1 '" - - possibility of carrying out combustion under pressure in the said chamber or chambers; the back pressure and exhaust gas from the gas turbine under optimal conditions during post-combustion in the fluidized bed chamber (s); - flexibility of the process depending on the load required by storing non-combustible gas condensed and / or | - particles of coal and / or use of the gas turbine without producing a driving force; '- possibility of obtaining partial preheating of the air after compression by passage through the flue gases of the boiler by the combustion chamber (s); with fluid bed idealized; | [- use of a gas turbine and a steam turbine powered from a single fuel (coal) under optimal conditions for each of these motive power production units.

The driving force is of course advantageously used to produce electrical energy using alternators according to conventional techniques.

The invention will be described in more detail with reference to a preferred embodiment of the invention, given solely by way of illustration without limitation. Reading this description will reveal other important advantages and characteristics of the invention.

The single appended figure represents a diagram of an installation in accordance with the invention.

In an i'-uur of py.r olysis τοχ “.an t the rep.- *» 5 general 1, pulverized coal is injected in 3, an electric heater 5 ensuring the airless distillation of this pulverized coal which undergoes a pyrolysis in a conventional manner. According to a particularly advantageous variant of the invention, steam from the boiler of the installation (which will be described below) is also injected into the electric heating zone of the pyrolysis oven * (item 7 A) Said pyrolysis oven is equipped at its upper part with a recuperator 9. At the top of the pyrolysis oven, on the one hand, solid particles of carbon are separated which are dedusted in a deduster 11.

I On the other hand, the volatile fraction circulates by a pump 13 to a condensation installation 15 equipped with a cooling coil 17. A liquid phase is taken from the bottom of the condensation tower while the non-condensed gases after passing through a dust collector 19 are brought to a gas turbine 21.

Bypass on the line bringing the carbon particles having the appearance of coke or semi-coke, a storage unit 23 is provided while a gasometer 25 makes it possible to store the non-condensed gases.

The gas turbine conventionally comprises an air compressor 22.

. The installation also includes at least one combustion chamber è fluidized bed bearing the general reference 27 which is supplied by the carbon particles coming from the dust collector 11 and by the exhaust gases of the gas turbine 21. The chamber (s) this combustion 27 constitutes a boiler supplying superheated steam i at the outlet of the steam turbine to be injected via line 7 A into the pyrolysis chamber.

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Advantageously, the fumes from the combustion chamber I with a fluidized bed also serve to preheat! the air supplied to the compressor 22 / the air circuit being i I shown diagrammatically by the coil 31.

! i Although an embodiment i ** has been described; Particularly preferred of the invention illustrated by the attached diagram, it should be understood that many operating variants remain possible.

3 «| It was indicated in particular that the injection of water vapor

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’J via line 7 A in the pyrolysis chamber in order to carry out hydropyrolysis constitutes an advantageous variant of the ir. But it is not compulsory.

- In the same way, the steam taken from the boiler constituted by the fluidized bed combustion chamber 27 can, if desired, come from another source depending on availability.

Complementary circulators can be i: also provided in the circuit while the gasometer 21 jj- and the storage 23 can be omitted.

ï It is also possible to provide several l,

Ir | combustion plants 27 in parallel or in series as well for the supply of exhaust gases from! of the gas turbine 21 that particles this carbon from î | of the dust collector 11.

In some cases, the gas turbine 21 may not produce a motive force, without modification of the connections.

\. —Ί | ! i - 9 -; The driving force obtained both in the gas turbine 21 and in the steam turbine 29 is advantageously used to drive an alternator i and the electrical energy produced can be used | \. especially for electric heating of the oven j | pyrolysis. It is also possible to use other energy sources to carry out the pyrolysis. The recuperator 9 can also be omitted while the 1 s 9.

| liquid taken from the bottom of the condensation tower 15 I can be used either in the installation described, l or for other uses, this liquid phase being% constituted essentially of hydrocarbons which can j 3 find numerous outlets.

• r! t It should be noted that depending on whether or not hydropyrolysis is used, the gaseous fraction i | fed to the gas turbine consists of hydra- 'to y "lower carbides with more or less' t! I contents important in hydrogen and caroone oxide, which É _ I allows this cnoisier the best operating conditions I of operating the installation of the invention, as a function of the gaseous fuel content of the coal used.

I An interesting operating variant of the invention is shown diagrammatically by the broken lines i of line 7E, which can be used as a replacement for line 7A, or in conjunction with it | arm to use steam as the pulverized coal fluid.

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Claims (12)

1. Improved method of producing energy, in particular electrical energy, in which the energy source consists of coal, characterized in j "] that the pulverized coal undergoes pyrolysis at a temperature of 500 ° C. 1200 ° C in a pyx-olysis oven, 4!;!,; I followed by a fractionation of a solid phase consisting \\! J of carbon particles having the appearance of cofce and a! Jj t il volatile phase consisting of a mixture of combustible gases II * and in that after at least partial condensation of the j liquefiable constituents of the volatile phase, the uncondensed gases dd dd 4 are supplied to the combustion chamber £ $ I d a gas turbine to burn with air from a compressor, producing combustion gases which are expanded in the turbine after which the exhaust gases, still under slight pressure, are conveyed)! at least one pi fluidized bed combustion chamber which is equal coal particles! j? from the pyrolysis furnace, with air supply of 1s “additional combustion with a view to causing combustion *: used to heat steam intended for a turbine?,‘ for steam. \ ‘ 2. Method according to claim 1 characterized I in that steam is injected into the furnace ce! pyrolysis to produce an additional amount of volatile gases 1. which is added to the gases from the pyrolysis? IBent speak, starting from the carbon particles formed during pyrolysis. 3. Method according to claim 1 or 2 c & racféns | in that more than one combustion chamber is used j. fluidized bed which are arranged in series. k - 11 - 4. Method according to claim 1 or 2 characterized in that more than one combustion chamber is used which are arranged in parallel. 5. Method according to any one of claim 1 to 4, characterized in that the air intended for the compressor of the gas turbine and / or the air injected into the fluidized bed is preheated using the fumes from the combustion chamber with a fluidized bed, after heating the steam intended to drive the steam turbine. 6. Method according to any one of claims 1 to 5 characterized in that the non-condensed combustible gases and the carbon produced during pyrolysis or hydrolysis are temporarily stored by creating a power station with variable charge according to energy needs from the moment. 7. Method according to any one of claims 1 to 6 characterized in that the gas turbine is used transiently without the production of motive force, the exhaust gases undergoing almost complete combustion in the combustion chamber (s) * fluidized bed. 8. Installation for the implementation of the method according to any one of claims 1 to 7 characterized in that it is constituted by a pyrolysis oven fed by pulverized coal, eventuellerer- "- 12 -% equipped with a recuperator, a device for separating carbon particles from volatile matter which is brought by a circulation fan into a condensation installation making it possible to separate the liquefiable fraction, a gas turbine supplied u with non-condensable gases coming from the installation of condensation and at least one fluidized bed combustion chamber supplied by the exhaust gases from the gas turbine and by the carbon particles originating from the pyrolysis and producing superheated steam which is sent to a steam turbine. 9. Installation according to claim 8 characterized in that it comprises storage installations constituted by a gasometer and by a solid matter storage chamber making it possible to temporarily store non-condensable gases and carbon particles respectively. 10. Installation according to claim "8 or 9 characterized in that the pyrolysis oven is equipped with a supply of steam from a boiler in order to carry out a hydropyrolysis reaction. 11. Installation according to claim 10 characterized in that the steam supply is made in the pyrolysis furnace, at the level of the electric heating zone of this furnace. 12. Installation according to claim 10 or 11 characterized in that the steam supply is used as the fluid carrying the pulverized coal.