WO2020002474A1

WO2020002474A1 - Installation and method for producing energy

Info

Publication number: WO2020002474A1
Application number: PCT/EP2019/067080
Authority: WO
Inventors: Frank Tabaries; Bernard Siret; Eddie MARCARIAN; Christophe Lehaut
Original assignee: Constructions Industrielles De La Méditerranée - Cnim
Priority date: 2018-06-28
Filing date: 2019-06-26
Publication date: 2020-01-02
Also published as: FR3083263A1; FR3083263B1

Abstract

In order to produce energy from biomass and another renewable energy source in an optimal manner, the installation according to the invention comprises a first steam generation system (100), having a combustion unit (101) for biomass and a boiler (102) including both a vaporizer (102.2) and a superheater (102.3). The installation also comprises a turbine unit (300) in order to turbine the superheated steam (4) produced by the superheater in order to produce energy, in particular electrical energy. The installation further comprises at least a second steam generation system (200, 200'), which is coupled to the first system, wherein the or each second system is adapted to produce steam (10, 10') from a renewable energy source other than biomass, which is sent to the boiler so as to supply the superheater in conjunction with the steam produced by the vaporizer. The boiler (102) furthermore includes a balloon (102.4) which is adapted to collect in a same internal volume of the balloon both the steam produced by the vaporizer (102.2) and the steam (10) produced by the or the at least one of the second systems (200, 200'), the balloon (102.4) being also adapted to supply the superheater (102.3) with the steam contained in the internal volume of the balloon.

Description

Energy production plant and method

The present invention relates to an installation and a method for producing energy from renewable energies.

The production of energy, in particular electricity, can be carried out by the combustion of a material, which delivers heat used to produce water vapor which is then turbinated to supply energy, in particular electricity.

Many fuels can be used. We can first mention petroleum products, natural gas, coal, lignite or coke. Solid recovery waste or residues can also be recovered energetically, such as household waste, industrial residues, etc., grouped under the acronym CSR for "Solid Recovery Fuel". Finally, biomass, such as wood or straw, can also be used as fuel.

That said, water vapor to be turbined to produce energy, in particular electricity, can also be produced by relying on heat sources other than combustion, such as geothermal or solar thermal .

Each of these various modes of energy production has its own advantages and disadvantages. In particular, the combustion of CSRs, which are products often containing a lot of chlorine, can only be carried out by limiting the temperature levels for the steam produced, for reasons linked to corrosion, fouling or deposit. of molten salts on the heat exchange equipment between the combustion fumes and the water to be vaporized. For its part, biomass, which is a renewable energy source, can feed cleaner combustion, producing water vapor at higher temperature, which allows an optimal thermodynamic cycle to be achieved. Regarding the other renewable energies that are thermal solar and geothermal energy, their use to produce energy does not generate C0 ₂ and, unlike nuclear energy, can be operated in small units or average; however, the temperature of water vapor produced by thermal solar or geothermal means often remains limited, in particular for reasons related to the technical and economic constraints inherent in these technologies. It is therefore understandable that systems for producing steam with different renewable energy sources, such as biomass and solar thermal or geothermal energy, are difficult to couple, in the sense that the temperature difference between the flows of steam generated respectively by these production systems prevents working in optimal thermodynamic conditions a turbine to which would be sent directly and separately the steam flows. US 2015/0007567 proposed to add a fuel boiler to a solar thermal power plant, the latter however not being used to produce water vapor but to heat the condensates resulting from the turbination of the steam produced by the boiler, before these condensates are returned to the boiler to be vaporized.

EP 2 623 778 discloses an installation and a method for producing electricity, which couple a system for producing steam from the combustion of biomass and a system for producing hot water from solar energy . The steam generation system from biomass combustion includes a boiler that heats an evaporator tank to produce steam sent to a superheater before being sent to a turbine. The evaporator flask is supplied with water which comes, in part, from condensate from the turbine, heated by a boiler economizer, and, for the rest, from solar collector tubes, these tubes being supplied by condensate of the boiler.

EP 3 130 770 discloses an installation and a method for producing electricity, which couple a boiler, supplied with heat by the combustion of biomass, and a system for producing steam, including both a vaporizer, supplied with heat by a solar unit, and a boiler supplied with heat by the combustion of an “auxiliary” fuel (coal, gas or fuel). The biomass boiler includes an economizer, a vaporizer and a superheater. The superheated steam from the biomass boiler is sent to a turbine. The water vapor produced by the solar vaporizer and the water vapor produced by the auxiliary boiler are provided saturated to be mixed in a common pipe before joining the superheater of the biomass boiler, in which they are directly admitted in input, together with the water vapor produced by the evaporator of the biomass boiler. The auxiliary boiler produces water vapor that complements or even replaces the water vapor produced by the solar evaporator, depending on the variations in solar energy received by the solar unit.

The aim of the present invention is to propose a new installation and a new process, which make it possible to produce energy in an optimized manner from biomass and from at least one other renewable energy source, such as solar. thermal or geothermal.

To this end, the invention relates to an energy production installation, as defined in claim 1.

The invention also relates to a method of producing energy, as defined in claim 8. The idea underlying the invention is to couple a first system for producing steam, based on the combustion of biomass, and at least a second system for producing steam, based on another renewable energy source, in particular thermal solar or geothermal energy, by providing that the coupling between these systems is done by sending water vapor, produced by the second system or systems, to the boiler of the first system. The energy produced by the or each second system is in the form of water vapor, possibly slightly overheated, which is not sent directly to a turbine unit, but which is sent together with the water vapor produced by the first system, to the superheater of the boiler of the first system, the output of this superheater being sent to a turbine unit. The above-mentioned turbine unit is therefore common to production systems and can operate under optimal thermodynamic conditions, in particular at high temperature and pressure levels for the superheated steam which is produced by the superheater of the first system from the combination water vapor produced by the first system, and water vapor produced by the second system (s). In other words, the invention makes it possible to couple a main system, which uses biomass as fuel and whose thermodynamic cycle is optimized for the turbination of the superheated steam which it produces, with one or more secondary systems, which use sources d renewable energy other than biomass and which operate at lower temperatures, in particular for technical and economic reasons. Of course, the invention can only be implemented if the production of water vapor of the first system, compared to the production of the second system, remains at a sufficient minimum level, below which the energy produced by combustion biomass will not be sufficient to ensure the overheating of the mixture of water vapors from the first and second systems respectively. The production of or at least one of the second systems passes through a balloon of the first system, this balloon making it possible to collect the water vapor produced by the vaporizer of the boiler of the first system and the water vapor, produced by this second system. The production of at least one other of the second systems can, if necessary, be directly admitted to the inlet of the superheater of the boiler of the first system. In all cases, the production of energy by the second system (s), which are non-emitters of C0 ₂ , can be continuous production or backup production, while being maximally valued: energy production by the second system (s) thus makes it possible to optimize the operating cost of the overall installation and to reduce the production of C0 ₂ reduced to a unit of energy produced, for example reduced to the MWh of electricity produced. Of more, the energy production according to the invention can be guaranteed at a target value, by regulating the first system so as to compensate for variations in production for the second system (s), so that the invention makes it possible to overcome energy storage systems, in particular electricity, without risk of production interruption.

Additional advantageous characteristics of the installation and of the process according to the invention are specified in the dependent claims.

The invention will be better understood on reading the description which follows, given solely by way of example and made with reference to the single figure which is a diagram of an installation according to the invention, implementing a process according to the invention.

In Figure 1 is shown an energy production installation, comprising a first steam production system 100 and a second steam production system 200, as well as a turbine unit 300.

The system 100 includes a combustion unit 101 designed to burn biomass. By way of nonlimiting examples, the biomass burned in the combustion unit 101 consists of wood, in particular in the form of chips, granules or fragments, straw, fodder and / or bagasse of sugar cane. More generally, the biomass envisaged here consists of products, waste and residues, composed of an agricultural or forestry plant material capable of being used as fuel in order to use its energy content: in essence, biomass is a source of renewable energy and the products, wastes and residues which compose it contain little chlorine and make a fairly clean combustion in the sense that the fumes from their combustion are only slightly corrosive and not very fouling for the equipment through which these fumes, fumes thus requiring only a relatively simple treatment. The fumes resulting from combustion by the combustion unit 101 are referenced 1 in the figure.

The system 100 also includes a boiler 102 which makes it possible to transfer the heat from the fumes 1 to the water 2 supplying this boiler. The boiler 102 thus makes it possible to recover part of the thermal energy resulting from the combustion of the biomass. At the outlet of the boiler 102, the fumes, referenced 3 in the figure, have a lower temperature than the fumes 1 and are sent to a smoke treatment unit 103 before being discharged. The smoke treatment unit 103 is based on known technology and will not be detailed here further.

The boiler 102 produces, from the water 2 supplying it, steam 4 which, at the outlet of the boiler, is sent to the turbine unit 300 to be turbinated therein and thus producing energy, in particular electrical energy. To produce water vapor 4 from water 2, the boiler 102 includes:

- an economizer 102.1 allowing the temperature of the water 2 supplying the boiler 102 to be raised,

- a 102.2 vaporizer used to vaporize the water heated by the economizer

102.1, and

a superheater 102.3 making it possible to superheat the water vapor produced by the vaporizer 102.2, the superheated water vapor coming from the superheater 102.3 forming the water vapor 4.

Each of the elements 102.1, 102.2 and 102.3 corresponds to a heat exchanger, which is based on a technology known per se and which makes it possible to recover the thermal energy of the fumes 1.

The boiler 102 also includes a balloon 102.4 making it possible to collect the water vapor produced by the vaporizer 102.2 and to supply with this water vapor the superheater 102.3. In other words, the balloon 102.4 serves both to store water vapor for the vaporizer 102.2 and as a nurse in water vapor for the superheater 102.3. In practice, the water vapor contained in the balloon 102.4 is dry or wet steam: wet steam means water vapor which is at a temperature equal to the dew temperature for the pressure considered, or else which contains a little water in liquid form; dry vapor means water vapor which is entirely in gaseous form and whose temperature is higher than the dew point temperature for the pressure considered.

According to a preferred operating mode of the system 100, the water vapor 4 produced by the superheater 102.3 has a temperature between 450 and 550 ° C. and a pressure between 80 and 130 bars relative, the system 100, in particular its superheater 102.3 , being adapted to bring the water vapor 4 to these temperature and pressure levels.

Note that, from a functional point of view, the 102.1 economizer, the vaporizer

102.2, the superheater 102.3 and the balloon 102.4 form, within the boiler 102, an integrated block, capable of supplying the superheated steam 4 from the water 2 supplying this block.

Outside the boiler 102, the water vapor 4 is turbinated by the turbine unit 300, seeing its thermodynamic condition change there, until forming, at the output of the turbine unit 300, a flow 5 admitted into a cooling unit 400, such as an air condenser. The turbine unit 300 comprises for example a turbine or a turbo-alternator. The liquid water 6 leaving the cooling unit 400 is sent to a condensate tank 500. A flow of liquid water, coming from the condensate tank 500, returns to the boiler 102, constituting the water 2 feeding this boiler, which thus loops the thermodynamic cycle of the water.

The system 200 comprises, for its part, a solar thermal collection unit 201 designed to collect solar energy and communicate it, in the form of heat, to water 8 supplying this thermal solar collection unit. The solar thermal collection unit 201 is based on a technology known per se: for example, this unit 201 heats the water 8 by concentrating the solar radiation thereon by a set of mirrors and / or lenses. In all cases, the water 8 supplying the solar thermal collection unit 201 comes from the condensate tank 500 and forms, at the outlet of the unit 201, a flow 10 consisting of water vapor.

The water vapor 10 is sent to the balloon 102.4 of the system 100, and this totally and directly, in the sense that all or part of this water vapor 10 is not introduced into the turbine unit 300 without passing through the boiler 102 of the system 100. Thus, the water vapor 10 produced by the solar thermal collection unit 201 is found, in the balloon 102.4, mixed with the water vapor produced by the vaporizer 102.2 of the boiler 102, to form the water vapor supplying the superheater 102.3 of the boiler 102. The balloon 102.4 is thus designed to, in the same internal volume of this balloon, together contain the water vapor produced by the vaporizer 102.4 and the vapor of water 10 produced by the solar thermal collection unit 201. In practice, to allow the circulation and regulation of the flow of water vapor 10 between the boiler 102 and the solar thermal collection unit 201, the water vapor 10 is produced by the thermal solar collection unit 201 at a pressure higher, in particular slightly higher, than the pressure of the internal volume of the balloon 102.4. Furthermore, according to an advantageous optional arrangement, the balloon 102.4 is equipped, at its entrance, with a mixer, making it possible to separately receive then mix the water vapor produced by the vaporizer 102.2 and the water vapor 10 produced by the solar thermal collection unit 201, before sending the resulting mixture into the internal volume of the tank 102.4.

In particular to facilitate the transport of the flow of water vapor 10 from the solar thermal collection unit 201 to the balloon 102.4, this flow 10 is mainly, or even exclusively, made up of dry water vapor.

In all cases, in particular for technical and economic reasons relating to the solar thermal collection unit 201, the temperature of the flow of water vapor 10 is lower than that of the vapor 4 leaving the boiler 102 and supplying the turbine unit 300. According to a preferred operating mode, the water vapor 10 is thus produced by the solar thermal collection unit 201 at a temperature which is both between 250 and 400 ° C, preferably between 250 and 380 ° C, and at least 100 ° C below the temperature of the vapor water 4.

As a variant, the invention may comprise, in addition to the system 200, one or more other systems for producing water vapor 200 ’: in FIG. 1, such an additional system is shown in dotted lines, being referenced 200’. This system 200 'includes a geothermal capture unit 201' making it possible to collect the thermal energy of the Earth and to communicate it, in the form of heat, to water 8 ', which feeds this geothermal capture unit 20T and which , like the water 8, comes from the condensate tank 500, so as to form, at the outlet of the geothermal capture unit 20T, a stream 10 'consisting of water vapor, this stream 10' being sent to the tank 102.4 similarly to flow 10. This variant illustrates the possibility of providing several systems, such as systems 200 and 200 ′, making it possible to produce water vapor, such as flows 10 and 10 ′, from various sources renewable energy other than the biomass used by system 100.

Of course, in a variant not shown, the system 200 can be eliminated in favor of the only system 200 ’.

As a variant, rather than passing the water vapor flows 10 and 10 ′ through the balloon 102.4, one or other of these flows 10 and 10 ′ may, preferably when these flows consist of dry water vapor, be directly admitted to the inlet of the 102.3 superheater to supply the latter together with the water vapor produced by the 102.2 vaporizer. In this variant, considerations similar to those developed above can advantageously be applied, concerning the temperature and pressure differentials between the boiler 102 and the systems 200 and 200 ’.

The installation described so far and the method implemented by this installation have multiple advantages.

In particular, the intelligent coupling of systems 100 and 200 and / or 200 'makes it possible to reduce the production of exogenous C0 ₂ per unit of energy produced, in particular per MWh of electricity produced, thanks to the use of biomass and other renewable energies.

Furthermore, the combustion unit 101 can be operated so as to regulate the total production of energy by the installation coupling the systems 100 and 200 and / or 200 ′. This regulation can for example be provided to reach a target value, requested by an electricity distributor to which the electricity produced by the turbine unit 300 is delivered. To do this, the power supply to the turbine unit 300 with the superheated steam 4 produced by the boiler 102 is maintained at a value predetermined, linked to the aforementioned target value of energy production, by regulating the system 100 as a function of variations in the water vapor flows 10 and / or 10 ′ sent by the thermal solar collection unit 201 and / or by the geothermal capture unit 201 'to the boiler 102: in practice, the aforementioned variations result from the actual level of production of water vapor by the systems 200 and / or 200', in particular in connection with diurnal or seasonal cycles , and also result from the possible shutdown of the systems 200 and / or 200 ′, in particular when one and / or the other of these does not operate continuously but for an additional production, or else when one and / or the other 200 and / or 200 'systems must be stopped to intervene on all or part of these systems. More generally, whatever the operating state of the systems 200 and / or 200 ′, the installation ensures the production of energy, in particular of electricity, thanks to the system 100 and to the turbine unit 300, in particular by avoiding an additional energy storage system which would be associated with systems 200 and / or 200 '.

Finally, various arrangements and variants to the installation and to the process described so far are conceivable.

Claims

1.- Energy production facility, comprising:

- a first water vapor production system (100), which includes:

- a combustion unit (101) adapted to burn biomass, and

- a boiler (102) adapted to transfer to the water (2) supplying the boiler the heat produced by the combustion unit, the boiler including both a vaporizer (102.2), adapted to vaporize the water supplying the boiler, and a superheater (102.3), adapted to superheat the water vapor produced by the vaporizer,

a turbine unit (300) adapted to turbine the superheated water vapor (4) produced by the superheater (102.3), in order to produce energy, in particular electrical energy, and

- at least a second system for producing steam (200, 200 '), which is coupled to the first system (100), the or each second system being adapted to produce, from a renewable energy source other than biomass, water vapor (10, 10 ') which is sent to the boiler (102) so as, together with the water vapor produced by the vaporizer, to supply the superheater (102.3),

characterized in that the boiler (102) further includes a tank (102.4) which is adapted to collect in the same internal volume of the tank both the water vapor produced by the vaporizer (102.2) and the steam d 'water (10) produced by the or at least one of the second systems (200, 200'), the tank (102.4) also being adapted to supply the superheater (102.3) with the water vapor contained in the volume internal of the balloon.

2.- Installation according to claim 1, characterized in that the or at least one of the second systems (200) comprises a thermal solar collection unit (201) adapted to produce, from the thermal energy of solar radiation , the steam (10) sent to the boiler (102).

3.- Installation according to one of claims 1 or 2, characterized in that the or at least one of the second systems (200 ') comprises a geothermal capture unit (20T) adapted to produce, from the Earth's thermal energy, water vapor (10 ') sent to the boiler (102).

4.- Installation according to any one of the preceding claims, characterized in that the superheater (102.3) is adapted to carry the steam superheated (4) which it produces at a first temperature, and in that the or each second system (200, 200 ') is adapted to bring the water vapor (10) which it produces to a second temperature which is both between 250 and 400 ° C and at least 100 ° C lower than the first temperature.

5.- Installation according to any one of the preceding claims, characterized in that the superheater (102.3) is adapted to bring the superheated steam (4) which it produces to a temperature between 350 and 550 ° C and at a pressure between 80 and 130 bars relative.

6.- Installation according to any one of the preceding claims, characterized in that the tank (102.4) is equipped, at the inlet, with a mixer which is adapted to receive separately and then mix the water vapor produced by the vaporizer (102.2), and the water vapor (10, 10 '), produced by the or at least one of the second systems (200, 200'), before sending the resulting mixture into the internal volume of the ball.

7.- Installation according to any one of the preceding claims, characterized in that at least one of the second systems (200, 200 ') is coupled to the first system (100) so that the water vapor (10 ), produced by this second system, is sent directly to the input of the superheater (102.3).

8.- Energy production process, in which we use:

- a first water vapor production system (100), which includes:

- a combustion unit (101) adapted to burn biomass, and

- at least a second water vapor production system (200, 200 '), the or each second system being adapted to produce, from a renewable energy source other than biomass, steam from water (10, 10 '), and

- a turbine unit (300) adapted to turbine the superheated water vapor (4) produced by the superheater (102.3), in order to produce energy, wherein the water vapor (10, 10 '), produced by the second system (s) (200, 200'), is sent to the boiler (102) so as, together with the water vapor produced by the vaporizer (102.2), supply the superheater (102.3),

and in which, before supplying, together with the water vapor produced by the vaporizer (102.2), the superheater (102.3), the water vapor (10), produced by the or at least one of the second systems (200, 200 '), passes through a balloon (102.4) of the boiler (102), in the same internal volume from which the water vapor produced by the vaporizer (102.2) and the water vapor are collected (10), produced by this second system (200, 200 ').

9.- The method of claim 8, wherein the water vapor (10, 10 '), produced by the second system (s) (200, 200'), has a temperature, which is both between 250 and 400 ° C and at least 100 ° C lower than the temperature of the superheated steam (4) produced by the superheater (102.3).

10.- Method according to one of claims 8 or 9, wherein the superheated water vapor (4) produced by the superheater (102.3) has a temperature between 350 and 550 ° C and a pressure between 80 and 130 relative bars.

1 1 .- A method according to any one of claims 8 to 10, wherein the water vapor (10) produced by at least one of the second systems (200, 200 ') is admitted directly to the inlet of the superheater (102.3).

12.- Method according to any one of claims 8 to 1 1, wherein the energy produced by the turbine unit (300) is electric, and wherein the first system (100) is regulated according to variations in the steam (10, 10 ') sent to the boiler (102) by the second system (s) (200, 200'), so as to maintain the supply to the turbine unit (300) at a predetermined value ) with the superheated steam (4) produced by the superheater (102.3).