JP5216783B2 - Plant and method for dry recovery / cooling of heavy ash and combustion control of residues with high unburnt content - Google Patents

Description

  The present invention relates to a plant and method for dry or primarily dry recovery / cooling and reduction of unburned material in heavy ash generated by boilers of the type used in solid fuel thermal power plants.

  The plant and its method are particularly unconventional fuels such as conventional solid fuels (typically coal dust) and especially biomass and / or municipal solid waste (RDF) derived fuels, especially under mixed combustion conditions. Suitable for boilers that burn.

The CO ₂ emission reduction request strongly demands the use of alternative fuels such as biomass and so-called “RDF” (fuel derived from municipal solid waste) instead of coal.

On the one hand, using mixed biomass and unprecedented fuels under co-firing with coal dust reduces overall CO ₂ emissions into the atmosphere, but on the other hand, like fuel crushing A series of problems related to complex combustion systems are derived. In fact, these alternative fuels, especially biomass, are very reactive to coal, but a significant amount of energy is used to grind them to the appropriate size / degree to ensure high combustion efficiency. I need. Further crushing to an excessive degree causes greater fatigue to the crusher members.

  Thus, in normal operation, it is preferable to grind biomass to a coarser stage in order to limit energy consumption and extend the life of the worn parts of the grinder member, thereby reducing combustion efficiency.

  As a result, the amount of unburned in heavy and light ash is increased simply by the partial burning of coarse biomass particles.

  The heavy ash is removed from the bottom of the combustion chamber by a dry recovery / cooling system, typically made as illustrated in EP 0 470 155 B1, and at least partially afterburning on those recovery systems To reduce unburned material content in the final ash.

  However, in known art plants, their post-combustion management mode is, above all, inferior to optimal conditions in the most important applications related to biomass and RDF utilization described above, and simply reduces the total amount of unburned material slightly. It is only reduced. In particular, there is a risk of post-combustion phenomena that cannot be controlled with known collectors in the plant, and this risk is also implicitly (full) measures to cause or promote such post-combustion. The usability will be limited.

  Thus, based on the above disclosure, the technical problem set up and solved by the present invention is a plant for post-combusting unburned material present in a dry or primarily dry heavy ash recovery system and A method is provided to overcome the above-mentioned drawbacks associated with known techniques.

  Such a problem is solved by a plant according to claim 1 and a method according to claim 30.

  Preferred features of the invention are in the dependent claims. The present invention provides several related advantages. The main advantage is that the present invention, above all, effectively and efficiently post-combusts the unburned material on the primary collector in the study of biomass or RDF co-firing, thereby It is to reduce the total content and at the same time prevent the risk of uncontrolled post-combustion.

  In particular, to facilitate the reduction of unburned material, the present invention typically provides recovery at the portion of the collector that is fitted with a belt located immediately downstream of the combustion chamber and facing the combustion chamber. It is preferable to operate both at the temperature of the produced heavy ash and the residence time of the heavy ash in an environment having a suitable temperature. As the temperature in the post-combustion zone rises and the residence time of the correlated zone fuel increases, the flammability rating of the fuel increases proportionally. The present invention provides a heated air inlet into the collector to raise the temperature, and in a preferred embodiment, the fuel residence time is adjusted by affecting the speed of the conveyor belt. In accordance with the present invention, in order to control the combustion process and prevent excessive amounts of biomass or RDF from causing uncontrolled heat generation—preferably normally provided in a plant to which the present invention is applied. Collected downstream of an electrical filter (or electrostatic precipitator) —combustion exhaust gas (fumes) is used to partially or completely replace combustible air.

  Therefore, the present invention creates a recovery environment in which the ash is moved to a more favorable location to reduce the unburned material present in the ash itself, and increases the post-combustion capacity of the dry or primarily dry collector. increase.

  According to the present invention, the combustion of unburned material on the belt of the collector afterburner can be controlled entirely by utilizing a combination of heated air and combustion fumes.

  As mentioned above, the post-combustion process preferably occurs and is completed in the collector zone corresponding to the throat section at the bottom of the boiler, and in some cases, if necessary and appropriate for plant requirements, It may happen in subsequent parts.

  In a further preferred embodiment, an in-boiler recirculation device is provided downstream of the part that properly cools the recovered heavy ash, with the light ash part rich in unburned material and the heavy ash together.

Always according to a preferred embodiment, an ash cooling section with air starts downstream of the post-combustion processing section, and the air is arranged in the end of the conveying device and / or in the secondary conveyor / cooling located downstream of the primary collector. Within the vessel (postcooler), a controlled and regulated amount is introduced into the collector. It is preferred to provide an ash grinding step at the exit of the conveyor-cooler and downstream to provide a screening section that can remove any plastic or metal residues in the ash. Accordingly, the storage, or in some cases it is possible to obtain ash suitable for recycling Sasera is in the boiler.

By Rukoto continuously recirculated portion of the light ash rich in unburnt in the combustion chamber, the electric filters (or electrostatic precipitator) duration of light ash is preferred to be reduced in the. Biomass or RDF unburned material is much more reactive than coal unburned material, and as such, when biomass or RDF is used there as a fuel, it accumulates in the hopper of the electric filter and thereby Although self-combustion can cause a fire, the present invention thus reduces the risk of fire within the electrical filter.

The reduction in the total amount of unburned material achieved through both post-combustion on the conveyor belt and recirculation into the combustion chamber saves consumption of ammonia used for NOx reduction in the catalyst. In fact, the same amount of unburned material in the whole ash without recirculation will require more excess combustion air, which will increase the NOx fraction in the exhaust gas, and The amount of ammonia required for reduction increases.

Summarizing the detailed description of the preferred embodiment reported below, the present invention collects heavy ash from the bottom of the boiler and combines flammable heated air and inert combustion fumes already available in the boiler. By using it, the post-combustion on the belt of the collector is promoted and adjusted, the ash on the belt is cooled, and in some cases they (all or part) are light with high unburned substance content together with part of the ash, Ru recycled to the boiler, a system that enables.

  Other advantages, features, and modes of operation of the present invention will be given by way of non-limiting example and will become apparent from the following detailed description of several preferred embodiments. Reference numerals are attached to the figures of the accompanying drawings.

It is the schematic of the whole example of preferable embodiment of the plant of this invention. It is sectional drawing along line AA of the collector | recoverer-afterburner of the plant of FIG. 2 is a detailed top plan view of a perforated collector belt of the plant of FIG.

  Referring to the previous figure, a combustion plant made in accordance with a preferred embodiment of the present invention is indicated generally at 1.

  The plant 1 is a type used in a solid fuel thermal power plant that burns solid fuel, particularly coal dust, and is suitable for combustion (mixed combustion) of fuel derived from biomass and / or municipal solid waste (RDF). Yes.

  In this example, the plant 1 is described in relation to biomass co-firing.

For the sake of clarity, the various components of the plant 1 will then mainly refer to the path through which the biomass passes, starting from collecting biomass from the storage means and leading to their combustion, and combustion residues. begins to collect goods from the bottom of the combustion chamber (or boiler) 12, the path traveled by the combustion residues up to the post-combustion thereof (heavy ash and light ash) or itself into the combustion chamber in some cases, the This will be described with reference to the recirculating and discharging route.

  Initially, the plant 1 provides as a biomass storage means a storage similar to that known per se and already used for coal. In the present embodiment, the biomass-dedicated storages are the two shown on the left side of FIG. The other reservoirs and associated additional components shown in FIG. 1 are understood to be used for coal and are therefore known types per se, so their construction and usage will be described hereinafter. No more considerations.

  The reservoirs 21 and 22 are preferably supplied at the top level to the burner of the combustion chamber 12 so that they have a longer residence time in the combustion chamber until heavier particles fall to the bottom. .

  Biomass is extracted from dedicated storages 21 and 22 by one or more conveyors 3 or augers similar to those already used for coal. In this way, the biomass is supplied by the shut-off valve 4 to a dedicated meter 5 having three outlets, indicated in this case by 51, 52 and 53, respectively, and from there one or more dedicated meters. The pulverizer is supplied to the three shown by 61, 62, and 63, respectively, in this case. In the embodiment of the present invention, the crushers 61 to 63 are realized by a hammer mill known per se.

  The conveyor 3 thus constitutes a bypass means of a known coal grinder, here denoted F, connected to the storages 21 and 22. Thus, by virtue of these bypasses, the plant 1 does not overly change its standard configuration for coal-only combustion and the known crusher F can also remain installed.

  The grinders 61-63 are suitable for reducing the biomass to the desired final end (exit) particle size. As will be better understood at the end of this description, the overall structure of the integrated plant 1 is designed to completely burn the biomass anyway, even if it is a “coarse” particle size. The final particle size need not be particularly fine.

  Downstream of the mills 61-63, in order to send biomass particles through a dedicated mechanical or pneumatic conveyor 8 to the meter 5 and then back into the same hammer mills 61-63 for fresh grinding, There are respective screening means 71, 72 and 73 suitable for blocking biomass particles having a particle size larger than a predetermined threshold.

  The fine biomass particles that have passed through the screening means 71 to 73 are transported to a single meter 10 by a common (shared) conveyor 9 and then fed to a known type of pneumatic conveyor 93 by a two-way valve 91. The pneumatic conveyor is already present in the existing solid fuel plant, combined with the crusher F. That is, the pneumatic conveyor 93 is developed from a coal crushing mill F (not used) coupled to the storages 21 and 22.

  The pulverized biomass is then introduced into a supply pipe for supplying coal dust, from which it is supplied to a boiler burner 12 of the type already present in an existing solid fuel plant.

  Once the coal and biomass fuel is supplied to the combustion chamber 12, the plant 1 and the recovery and post-combustion processes performed therein are performed as described below.

  The fly ash leaves the combustion chamber 12 through a conventional duct for flue gas emission, indicated generally at 13 in FIG. Alternatively, heavy ash portions and any unburned material settle to the bottom and are collected on a conveyor-type dry collector 14 such as the subject of EP 0471555. Therefore, it will not be further described here.

  According to the present invention, post-combustion of unburned material proceeds at the part facing the combustion chamber 12 on the recovery unit 14, particularly on the post-combustion or afterburner combustion part 141. For this purpose, the upper surface of the belt of the collector and in particular the upper surface of the part 141 receives heat from the burner of the combustion chamber 12 by radiation.

  According to an improved embodiment, the plant of the present invention uses unburned biomass to recover 14 itself, as also shown in FIG. 1, to initially burn unburned biomass in the post-combustion zone 141. A biomass meter 18 and a feeder 19 independent of the combustion chamber 12 may be provided upstream of the collector 14 (or at least upstream of the portion 141 or a portion corresponding thereto) so as to be directly supplied to the combustion chamber 12. In this case, the initial drying of the biomass may be performed by supplying heated air to the feeder 19, which is already present in the existing thermal power plant and is introduced below It may be advantageous to come from the exchanger 29.

  According to the present invention, the control means 100 for controlling the post-combustion of the unburned material generated in the post-combustion portion 141 is provided in order to increase the efficiency of the post-combustion and at the same time avoid the progress of the uncontrolled phenomenon.

  The means 100 includes heating air supply means 15 suitable for supplying heated air and a flow of combustion fumes, respectively, in order to promote and suppress post-combustion in a portion corresponding to the post-combustion portion 141, respectively. And means 150 for supplying combustion exhaust gas (smoke).

  In the present embodiment, the supply means 15 and 150 collect heated air from an air chamber 151 coupled to the boiler 12 and exhaust fumes from downstream of the electric dust collector (electric filter) 28 of the plant 1, respectively. Each with a conduit.

  Typically, the heated air in the air chamber 151 comes from the exchanger 29 described above, which in this embodiment is a fume / air exchanger located downstream of the combustion chamber 12 that draws external air. In order to heat, the residual heat of combustion fumes is used appropriately. According to an improved embodiment, the heated air supplied by the means 15 can be extracted directly from the latter exchanger 29.

  The air chamber 151, air preheater 29, and electrostatic precipitator 28 are well known to those skilled in the art and already exist in known plants. Therefore, it will not be further described.

  The heated air supply means 15 is one or more valves formed in a means 143 for controlling (regulating) introducing external air, for example in the casing of the collector 14, and preferably controlled by the control means 100. An inlet coupled to the collector 14 for allowing the air introduced into the collector 14 to have a desired oxygen concentration and a suitable temperature.

  Thus, heated air supplied by means 15 and proportioned to atmospheric air in an appropriate proportion can reach the optimum temperature for post-combustion on the collector / afterburner belt 14.

  The means 143 can also use the negative pressure existing in the combustion chamber 12 to supply air from the outside.

  The heating air supply means 15 and the fume supply means 150 have an overall configuration suitable for supplying a counter flow with respect to the traveling direction of the belt of the collector 14 at least in the post-combustion portion 141 described above. Is preferred.

  Both the air supply means 15 and the fume supply means 150 may each comprise means for automatically adjusting the flow rate, which are respectively indicated by 102 and 103 in FIG.

The control means 100 is suitable for adjusting the flow rate of heated air and / or fumes supplied to the post-combustion part 141, which for this purpose preferably corresponds to the part corresponding to the post-combustion part 141. Depending on the temperature detected by a suitable sensor arranged in the automatic means for adjusting the flow rate of the air and fumes. When the temperature value exceeds a preset threshold, the haze flow rate is increased and, as a result, the heated air flow rate is decreased. Therefore, the oxygen concentration is reduced and the combustion rate is reduced. In particular, the fumes generated in the combustion process of the boiler can be used as an inert gas due to the low O ₂ concentration in the fumes (<6%) and absorb or displace flammable air on the belt. It is possible to adjust or stop the combustion. Conversely, when the temperature is below a preset threshold, the injection of fumes is stopped, the flow rate of heated air is increased, and in some cases the flow rate of room temperature air introduced by means 143 is also decreased.

  In order to move the fumes, additional fans may be installed to supply them with the heads required to inject them into the collector / afterburner 14 if necessary.

  In order to avoid the problem of acid condensation, the fume piping of the supply means 150 should be insulated so as to be properly maintained above the condensation temperature.

  The fumes used to control the combustion exhibit an appropriate cooling capacity in addition to the fire extinguishing capability because their temperature is not higher than 150 ° C. In fact, in this embodiment, the fumes come from the downstream zone of the electrical filter, i.e. they are collected after having already lost their heat capacity.

  Thus, according to an improved embodiment, the post-combustion portion 141 is concentrated exclusively or nearly exclusively in a zone that receives radiation at the lower throat of the boiler 12 and is heated in the manner disclosed above. Controlled by supplying air and / or fumes. The portion of the collector belt that does not face the bottom of the boiler is rather dedicated to cooling, and cooling is performed by supplying combustion fumes (with dedicated means) and cold air (with means 143 described above). Take advantage of the negative pressure in the boiler, carefully put the fluid into the conveyor transport zone, and allow the fluid to lick the cover of the collector 14 to cool it.

  Finally, as a further option for the control of combustion, it is precisely metered by the distribution nozzle 104, preferably in the multiple zones of the collector / afterburner 14, in particular in the (at least) primary grinding zone (ie ash In the end of the collector 14 with respect to the direction of travel), the supplied water can be used.

  According to a preferred refined embodiment, the heated air supplied by the means 15 is recovered particularly under the belt of the collector 14 in a flow opposite the heavy ash and unburned material flow as described above. Supplied under the part 141 of the vessel. In this case, in order to make heat exchange and post-combustion more effective and efficient, the belt of the collector 14 may include a through hole (hole) or a slot 142 shown in FIG. Thus, in addition to heating the bottom of the collector 14, the heated air traverses the bed of ash and unburned material, partly returning to the combustion chamber 12 due to the negative pressure present in the combustion chamber, Return heat to. Such an air path is enhanced by the pressure differential that exists between the bottom of the belt conveyor and the bottom of the boiler. The passage of heated air through the holes in the belt conveyor of the collector 14 allows the air itself to contact the ash on the belt more and more efficiently, resulting in the combustion of unburned material. Increase efficiency.

  As already mentioned above, in this embodiment, in order to control and introduce external cooling air, on the side wall of the collector 14-in particular, the part corresponding to the end of the belt that is not typically involved in post-combustion. -An air introduction means 143 is further provided.

  Heavy ash and unburned material are fed from the collector 14 to the secondary belt conveyor 16 and used for post-cooling, and it is preferably water cooled through the primary grinder 20 to withstand high temperatures. A moving hopper 201 whose sketch is simply shown in FIG.

  As already described in EP 0 471 555, the counter pressure supplying external air through a controlled inlet 160 present on the side wall of the casing of the conveyor 16 itself, taking advantage of the negative pressure present in the combustion chamber. Air-assisted cooling of the ash is performed on the cooling conveyor 16 by the in-stream system.

  According to a preferred improved embodiment of the invention, the hopper 201 is part of a pressure shut-off system suitable for creating an appropriate pressure separation between the atmosphere of the collector 14 and the atmosphere of the cooling conveyor 16. Form. For this purpose, the hopper 201 forms a means for accumulating the transported material, forming a head of material between the environments and making it possible to create the pressure separation.

  The pressure shut-off system is based on International Patent Application No. PCT / IT2006 when needed, and typically based on ash temperature and flow sensing performed, such as upon discharge onto the collector 14. As described in US Pat. No. / 000625, the introduction of excessive amounts of cooling air into the combustion chamber 12 can be avoided by appropriately and selectively activating pressure separation, so that air assisted cooling of ash is achieved. It becomes possible to manage more effectively.

  The head of material that forms at the level of the hopper 201 can be adjusted by affecting the relative and absolute forward speeds of the conveyors 14 and 16.

  When the pressure shut-off is activated, the heated air exiting the conveyor 16 begins at the end of the conveyor 16 itself and is further fed into the fume conduit 13 of the plant 1 by means of a further suitable conduit 25 with means for automatically adjusting the flow rate. The portion 26 is supplied. The coupling between the aftercooler 16 and the boiler side may take place upstream or downstream of the above-described air preheater 29 (fog side) arranged along the haze conduit 13. The cooling air introduced into the aftercooler 16 is recovered through the coupling by the negative pressure value existing in the boiler side zone.

  The plant 1 preferably also includes a bypass line or conduit (not shown in the figure for clarity) that couples the collector / afterburner 14 with the conveyor-cooler 16 and includes an automatic open / close valve.

  Downstream of the cooling conveyor 16, suitable for crushing only the ash without changing the particle size of any plastic material mixed with ash and resulting from RDF combustion, and in particular the ash particle size can be reduced, An opposing roll type or equivalent type secondary crusher 202 is provided. This type of pulverizer is already known to those skilled in the art, and the plastic particles pass through the roll without deformation but breaking.

  Therefore, located downstream of the secondary grinding stage (step) to separate ash from the plastic particles and any metal parts present in the RDF that are stored or routed for disposal by dedicated means, Associated with the device 202 is a mechanical or pneumatic screening system 203.

Milled ash, as described in International Patent Application No. PCT / EP2005 / 007536, as recycled Sasera are as combustion chamber coal pulverization mills and Boirabana, mechanical or pneumatic conveyor 204 To be sent to a coal pulverization mill.

  With respect to the combustion fumes generated in the combustion chamber 12 described above and the path of the light ash carried thereby, the fumes cross the zone of the economizer 27 and then pass through the fume conduit 13 and possibly initially in this specification. Across the air / fume exchanger 29 described in the document and into the light ash electrostatic precipitator 28 described herein, or equivalent means.

Light ash precipitated in the electrostatic precipitator 28 is collected by a suitable means 30 in order to recycle them into the combustion chamber.

Thus, in summary, after post-combustion on the belt of the collector 14, any unburned material still present in the heavy ash will be light with high unburned material content after being properly cooled by the conveyor 16. with ash, in order to achieve complete conversion of unburned substances it is recycled to the combustion chamber.

  Furthermore, the plant 1 incorporates a central coordination and management system that can reliably perform the steps described herein.

Thus, the described plant now has unburned material present in the heavy ash by controlled post-combustion treatment of such produced heavy ash on the collector belt and by recirculation into the boiler. It will be appreciated that reducing light ash with high unburned material content coming from electrical filters can be achieved.

  Furthermore, the integrated system for dry recovery, grinding, biomass post-combustion, and heavy ash and unburned material recirculation described above enhances the combustion capacity of biomass (and generally unconventional fuels). It will be appreciated that it increases its combustion efficiency.

  The described system allows both the use of equipment already present in an existing thermal power plant, a reduction in plant construction costs, and a minimum of adjustment measures required for the existing plant. In particular, the transfer of biomass (and generally unconventional fuel materials) continues with the means used for the transfer of coal and heavy ash. Furthermore, boiler storage, which is now a traditional means for accumulating solid fuel materials, can still be used for biomass.

Unlike the latest technology, which uses a coal mill to atomize light ash and heavy ash, add heavy ash to light ash with a large amount of unburned material , and recirculate it into the combustion chamber, the present invention provides preheating. It is also understood to optimize the mixed combustion of biomass in a coal-fired boiler by using a portion of the generated air to burn biomass directly on the collector belt and recirculate heavy ash. It will be.

  It will also be understood that the present invention is compatible with methods of burning (co-firing) biomass in a solid fuel fired power plant of the type described above. The method allows dry recovery of heavy ash and unburned material from the combustion chamber 12 by the collector 14 of the type described above, with the flow of heated air and combustion fumes in the portion corresponding to the portion 141 of the collector. Of the heated air and / or fumes fed into the post-combustion section to cause controlled post-combustion post-combustion and to promote and inhibit post-combustion respectively. Adjust the flow rate.

  The preferred properties of the method have already been described with reference to the plant 1.

  Finally, the integrated system described herein optimizes the combustion efficiency of biomass (and unprecedented fuel in general) and plant management, but for the different characteristics of the present invention, And in particular, for each of the aspects described above for a system for controlling combustion by air and fumes, a dedicated grinding system, a biomass post-combustion system, and means for direct combustion of biomass on a collector by a dedicated meter. It will be appreciated that split protection may be required to provide a significant improvement in the efficiency.

  The invention has been described above with reference to preferred embodiments thereof. It should be understood that there may be other embodiments that fall within the scope of protection of the appended claims.

Claims (58)

In a combustion plant (1) suitable for use in a solid fuel thermal power plant in connection with a combustion chamber (12) of the type suitable for combustion (mixed combustion) of fuels derived from biomass and / or municipal solid waste (RDF) There,
Dry collector (14) for heavy ash and unburned material from the combustion chamber (12), suitable for being located at the bottom of the combustion chamber (12) for receiving heavy ash from the combustion chamber (12) A dry collector (14) having a post-combustion part (141) for said unburned material;
Control means (100) for controlling the post-combustion of the unburned material occurring on the post-combustion part (141), the heating air supply means (15) for supplying heated air and the combustion chamber (12) The combustion fume supply means (150) for supplying the combustion fume generated in the above, and the flow of heated air and combustion fume in the portion corresponding to the post-combustion portion (141) in order to promote and suppress the post-combustion, respectively Control means (100) suitable for selectively adjusting the flow rate of heated air and / or combustion fumes supplied to the post-combustion part (141);
A combustion plant (1) comprising:   The post-combustion part (141) is suitable to be arranged at least partly facing the bottom of the combustion chamber (12), so that the post-combustion part is from the combustion chamber (12) itself. The plant (1) according to claim 1, wherein the plant (1) has an overall configuration that utilizes radiant heat.   An air flow in which the heated air supply means (15) and / or the combustion fume supply means (150) flows backward in the moving direction of the dry collector (14) at a portion corresponding to the post-combustion portion (141). The plant (1) according to claim 1 or 2, configured to supply   The control means (100) comprises automatic means for adjusting the flow rate of the heated air and / or the combustion fumes depending on the temperature detected in the part corresponding to the post-combustion part (141). The plant (1) according to any one of claims 1 to 3.   In order to promote the circulation of air and / or fumes, the heated air supply means (15) and / or the combustion fumes supply means (150) effectively use the negative pressure present in the combustion chamber (12). The plant (1) according to any one of claims 1 to 4, which has an overall configuration suitable to do.   The control means (100) comprises means (143) for controlling and introducing external air mixed with the heated air of the heated air supply means (15). Plant (1) according to paragraph.   The heated air supply means (15) collects heated air from the air chamber (151) or the preheater (29) or is suitable for collecting the heated air, and supplies heated air to the combustion chamber (12). The plant (1) according to any one of the preceding claims, which is suitable.   The plant (1) according to any one of the preceding claims, wherein the combustion fumes supply means (150) collects or is suitable for collecting the combustion fumes downstream of an electrostatic precipitator (28). 1).   The plant (1) as described in any one of Claims 1-8 which has the whole structure made the temperature of the said combustion fumes supplied by the said combustion fumes supply means (150) being 150 degrees C or less.   Plant (1) according to any one of the preceding claims, wherein the combustion fume supply means (150) comprises a fan for increasing the flow head.   The plant (1) according to any one of the preceding claims, wherein the dry collector (14) has a side inlet (143) for controlling and introducing external air.   A recovery in which the dry collector (14) has a plurality of through holes (142) suitable for enhancing a path of air passing through a substance to be conveyed at least in a portion corresponding to the post-combustion portion (141). The plant (1) according to any one of the preceding claims, comprising a machine belt.   The means (104) for supplying a cooling water in the said dry-type collector (14) arrange | positioned at least in the part corresponded in the terminal part of the said dry-type collector (14) is provided in any one of Claims 1-12 The plant (1) according to claim 1.   The plant (1) according to any one of claims 1 to 13, comprising adjusting means for adjusting the residence time of the unburned material in the post-combustion part (141).   The plant (1) according to claim 14, wherein the adjusting means is based on controlling the speed of the dry collector (14).   The plant (1) according to any one of the preceding claims, comprising a cooling conveyor (16) arranged downstream of the dry collector (14).   The plant (1) according to claim 16, comprising pressure shut-off means (201) suitable for creating a pressure separation between the atmosphere of the dry collector (14) and the atmosphere of the cooling conveyor (16). .   18. The pressure blocking means comprises means (201) for accumulating the conveyed material suitable for forming a material head between the atmosphere causing the pressure separation. Plant (1).   The plant (1) according to any one of the preceding claims, comprising recirculation means (30) for recirculating light ash into the combustion chamber (12). It said recirculation means (30), electrostatic precipitator from (28), or from the immediately downstream, comprises a means for collecting the light ashes, plant according to claim 1 9 (1).   21. Plant (1) according to any one of the preceding claims, comprising means (204) for recirculating unburned material contained in heavy ash in the combustion chamber (12).   The means according to any of the preceding claims, comprising means for supplying the combustion fumes into the ash cooling zone, located downstream of the post-combustion part (141) of the dry collector (14). The plant (1) described.   The feeder comprises an unburned biomass feeder (18, 19) disposed upstream of or corresponding to the post-combustion part (141) of the dry collector (14) and independent of the combustion chamber (12). The plant (1) according to any one of the preceding claims, wherein (18, 19) is suitable for placing unburned biomass directly on the dry collector (14). Wherein suitable for performing primary drying of unburned biomass, comprising means for supplying heated air to said feeder (19), the plant according to claim 2 3 (1).   The plant (1) according to claim 24, wherein the means for supplying the heated air to the biomass is associated with an air / combustion fume exchanger (29).   A dedicated crushing means (61-63) installed or suitable for being installed upstream of the combustion chamber (12) and suitable for crushing the biomass according to a predetermined maximum outlet particle size. The plant (1) according to any one of Items 1 to 25.   27. Plant (1) according to claim 26, wherein the dedicated grinding means (61-63) comprise one or more hammer mills.   28. Plant (1) according to claim 26 or 27, comprising bypass means (3) suitable for supplying the biomass from a storage store (21, 22) to the dedicated grinding means (61-63).   Disposed downstream of the dedicated grinding means (61-63), suitable for blocking biomass particles having a particle size larger than a predetermined threshold and resending them to the dedicated grinding means (61-63), 29. Plant (1) according to any one of claims 26 to 28, comprising screening means (71 to 73). A combustion method suitable for use in a solid fuel thermal power plant comprising a combustion chamber (12) of the type suitable for combustion (mixed combustion) of biomass and / or municipal solid waste (RDF) derived fuel,
The method achieves dry recovery of heavy ash and unburned material from the bottom of the combustion chamber (12) by a collector (14) located downstream of the combustion chamber, the method further comprising the recovery Post-combustion of the unburned material in a post-combustion portion (141) of the vessel (14), wherein the post-combustion step includes a flow of heated air and Controlled by selectively supplying a flow of combustion fumes generated in the combustion chamber (12), the flow rate of the heated air and / or the combustion fumes supplied to the post-combustion portion (141) is adjusted. The way.   The post-combustion part (141) is arranged to at least partially face the bottom of the combustion chamber (12), whereby the post-combustion part utilizes radiant heat from the combustion chamber (12) itself; The method of claim 30.   32. The method according to claim 30 or 31, wherein the step of supplying the heated air and / or the combustion fumes supplies a flow that flows backward with respect to the direction of travel of the combustion residue at a portion corresponding to the post-combustion portion (141). The method described.   33. The flow rate of the heated air and / or the combustion fumes is automatically adjusted depending on the temperature sensed at a portion corresponding to the post-combustion portion (141). The method described in 1.   Supplying the heated air and / or the combustion fumes effectively uses negative pressure present in the combustion chamber (12) to facilitate the circulation of air and / or fumes. 34. A method according to any one of 33.   35. A method according to any one of claims 30 to 34, wherein a controlled supply of external air into the post-combustion part (141) is provided.   The heated air supply step comprises collecting heated air from a preheater (29) or air chamber (151), both suitable for supplying heated air to the combustion chamber (12). 36. The method according to any one of -35.   37. A method according to any one of claims 30 to 36, wherein supplying the combustion fumes comprises collecting the combustion fumes downstream of an electrostatic precipitator (28).   38. A method according to any one of claims 30 to 37, wherein the temperature of the combustion fumes fed into the post-combustion part (141) is about 150 <0> C or less.   39. A method according to any one of claims 30 to 38, wherein the step of supplying the combustion fumes realizes the use of exhaust means to increase the flow head.   40. A method according to any one of claims 30 to 39, wherein a controlled supply of external air into the dry collector (14) is provided.   The method according to any one of claims 30 to 40, wherein cooling water is also supplied into the collector (14) disposed at least in a portion corresponding to a terminal portion of the collector.   42. A method according to any one of claims 30 to 41, wherein adjustment of the residence time of unburned material in the post-combustion zone (141) is performed.   43. The method of claim 42, wherein the adjustment is based on controlling the speed of the collector (14).   44. A method according to any one of claims 30 to 43, comprising a cooling step downstream of the recovery performed by the collector (14).   45. The method of claim 44, providing an option to activate a pressure shutoff between the atmosphere of the collector (14) and the atmosphere of the cooling step performed downstream thereof.   46. The pressure shut-off according to claim 45, wherein the pressure shut-off is actuated by means (201) for accumulating the conveyed material suitable for forming a head with material during the atmosphere creating the pressure separation. Method.   47. A method according to any one of claims 30 to 46, wherein light ash is recycled in the combustion chamber (12).   48. The method of claim 47, wherein the light ash that is recycled is collected from an electrical dust collector (28) or immediately downstream thereof.   49. A method according to any one of claims 30 to 48, wherein unburned material contained in the heavy ash is recycled in the combustion chamber (12).   50. A method according to any one of claims 30 to 49, wherein the ash cooling step performed by the combustion fumes is performed.   51. The method of claim 50, wherein the cooling step is performed on the collector (14).   52. The method according to any one of claims 30 to 51, wherein the unburned biomass is fed directly onto the collector (14) upstream of or corresponding to the post-combustion part (141).   53. The method according to claim 52, wherein supplying heated air to an unburned biomass feeder (18, 19) is performed for primary drying of the unburned biomass. 54. The method of claim 53 , wherein the heated air supplied to the biomass is obtained by heated air / combustion fumes heat exchange.   55. A method according to any one of claims 30 to 54, which provides for the use of dedicated grinding means (61-63) suitable for grinding the biomass according to a predetermined maximum terminal (exit) particle size.   Storing said biomass in said same type of storage (21, 22) used for solid fuel, and said biomass from said storage (21, 22) to said dedicated grinding means (61-63) 56. The method of claim 55, wherein providing is performed.   57. Method according to claim 56, wherein the biomass store (21, 22) is tied to a burner of the combustion chamber (12) arranged at the top level.   A screen is provided downstream of the dedicated grinding means (61-63) for blocking biomass particles having a particle size larger than a predetermined threshold value and retransmitting them to the dedicated grinding means (61-63). 58. A method according to any one of claims 55 to 57.