Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
  • F23G5/00—Incineration of waste; Incinerator constructions; Details, accessories or control therefor
  • F23G5/30—Incineration of waste; Incinerator constructions; Details, accessories or control therefor having a fluidised bed
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
  • F23G5/00—Incineration of waste; Incinerator constructions; Details, accessories or control therefor
  • F23G5/50—Control or safety arrangements
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
  • F23G7/00—Incinerators or other apparatus for consuming industrial waste, e.g. chemicals
  • F23G7/001—Incinerators or other apparatus for consuming industrial waste, e.g. chemicals for sludges or waste products from water treatment installations
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
  • F23G2203/00—Furnace arrangements
  • F23G2203/50—Fluidised bed furnace
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
  • F23G2207/00—Control
  • F23G2207/10—Arrangement of sensing devices
  • F23G2207/101—Arrangement of sensing devices for temperature
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
  • F23G2207/00—Control
  • F23G2207/20—Waste supply
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
  • F23G2209/00—Specific waste
  • F23G2209/12—Sludge, slurries or mixtures of liquids

Definitions

• the present invention relates to an incineration furnace for pasty products, in particular sludge for purification plants, with a bed of fluidized granular material by injecting a gaseous fluid, the furnace being of the kind comprising at least two nozzles injection of pasty products into the bed, fed respectively by a pipe provided with a valve and connected to the discharge of the same pump, and a flue gas discharge duct.
• the most effective injection is that obtained by pumping directly back into the bed of granular material. Indeed, the pasty products are then finely distributed in the l it of granular material and the combustion is the most efficient and the most complete.
• the injection of the product is carried out through a limited number of nozzles inside the bed.
• this type of injection can cause several problems: on the one hand an injection nozzle can clog without this obstruction is quickly observed, on the other hand, this clogging can cause carbonization of the sludge at the orifice and permanent plugging of the injection nozzle.
• a first solution consists in cyclically closing each of the injection nozzles of the furnace fed by the same pump: this pump pushes the products into the furnace alternately, thanks to a set of valves, by only one of the nozzles.
• the pasty products, especially mud, are forced out through this nozzle, which causes its uncorking.
• This solution has several disadvantages. It requires the installation of automatic batch valves that operate frequently and will wear out relatively quickly. In addition, this solution generates a high pressure drop to permanently pass the whole of the p rod u it dansuneseulebu se, which entails an oversizing of the pump.
• Another solution is the use of a pump by injection nozzle.
• the injection is perfectly controlled by setting up a flowmeter on each pump.
• this solution is expensive because the pumps under pressure are a significant cost.
• the invention can be used to provide an incineration furnace for controlling the injection of the pasty products, and the unblocking of the nozzles, when necessary, for a moderate cost.
• an incineration furnace of pasty products, in particular sludge of purification plants, with a bed of fluidized granular material by injection of a gaseous fluid, of the kind defined above is characterized in that the furnace comprises at least two temperature sensors arranged above the bed of granular material, each temperature sensor being located in an area associated with at least one injection nozzle, and means sensitive to a temperature difference between the sensors, clean to detect, when the temperature difference exceeds a determined value, the clogging of at least one nozzle.
• the means sensitive to the temperature difference between the sensors is able to cut off the supply of sludge from the nozzle or the nozzle (s) associated with the temperature sensor indicating a temperature higher than that provided by the other sensor.
• the sensitive means comprises an automaton adapted to control the cutoff of the pasty product feed, in particular sludge of the, or nozzle (s), associated with the temperature sensor indicating a higher temperature, in at least 10 ° C, to that provided by the other sensor.
• an automaton adapted to control the cutoff of the pasty product feed, in particular sludge of the, or nozzle (s), associated with the temperature sensor indicating a higher temperature, in at least 10 ° C, to that provided by the other sensor.
• the bed of granular material can be fictitiously configured in angular sectors, in particular of equal size, and at least one injection nozzle is associated with each angular sector.
• each temperature sensor is disposed vertically above an injection nozzle, or the median zone of a group of nozzles associated with the sensor.
• each temperature sensor may be disposed in a portion of the zone associated with each nozzle or group of nozzles.
• Each temperature sensor may be at a distance of between 0.1 and 2 meters above the bed of granular material, all of these sensors constituting a first series.
• each temperature sensor of this first series is at a distance of 0.5 meters above the bed of granular material.
• the furnace may comprise a second series of temperature sensors located above the first series of temperature sensors.
• Each temperature sensor of the second series may be at a distance of between 1.5 and 8 meters above the bed of granular material.
• each temperature sensor of the second series is at a distance of about 2 meters above the bed of granular material.
• the oven may comprise two injection nozzles, diametrically opposed, each nozzle being surmounted by a temperature sensor.
• the furnace may comprise four injection nozzles, two nozzles being assigned to a first semicircular angular sector surmounted by a first temperature sensor and two other nozzles being assigned to a second semicircular angular sector surmounted. a second temperature sensor.
• Each injection nozzle may have an inverted V shape, with narrowing of the passage section to the outlet, capable of creating a pressure drop at least equal to the maximum difference in pressure drop between two lines of injection of pasty products from the discharge of the same pump.
• Fig. 1 is a diagram of a first embodiment of an oven according to the invention
• Fig. 2 is an enlarged diagram of the sludge injection zone of FIG. 1,
• Fig. 3 is a schematic cross-section of FIG. 1, and
• Fig. 4 is a view similar to FIG. 3 of another embodiment of the invention.
• a furnace 1 for incineration of pasty products particularly sewage sludge, fluidized bed granular material, including sand.
• the oven 1 comprises in its lower part a wind box 2 above which is disposed a bed of sand 3.
• the wind box 2 is connected to the discharge of a fan, not shown, for blowing air at through the bed 3.
• unrepresented pipes allow the passage of air from the air box to the sand bed 3 to ensure the fluidization of the sand.
• Above the sand bed is an afterburner zone 4 surmounted by an orifice and a flue outlet pipe 5.
• Two injection nozzles 6 and 7 located on either side of the sand bed 3, preferably diametrically opposite, allow the injection of sludge to be incinerated in the sand bed 3.
• the supply of the nozzles 6 and 7 is regulated by the opening and closing of valves 8 and 9 respectively, preferably solenoid valves.
• the pressurized sludge is supplied via pipes and a pump 10.
• Temperature sensors in particular thermocouples 11, 12, 13, 14, have been installed above the sand bed, vertically above the nozzles 6 and 7 ( Figures 1 and 3). This configuration makes it possible to detect whether the pasty product is well injected by each nozzle considered. In the sand l it is not possible to notice a clogging, because the turbulence in the l it, caused by the air injection horizontally which is transformed into vertical movement, is very strong and there is a true homogenization of the bed. The observation made above the sand bed suggests that the flow of air, become vertical, depends for a lot of what happens at its lower vertical. In addition, the burning of the pasty material takes place in two stages: one part in the sand bed and another part above. It is the inhomogeneity of this second part which is detected.
• a temperature measurement in the sand bed 3 would make it possible to detect the presence of a global problem, if a sensible variation of temperature were detected, but not to precisely locate the problem.
• the n0 is the average altitude of the upper surface of the sand bed 3.
• two thermocouples 11 and 12 are arranged, constituting a first series.
• the thermocouple 1 1 is disposed vertically of the injection nozzle 6 while the thermocouple 12 is disposed vertically of the injection nozzle 7.
• the level n1 altitude at which the thermocouples 1 1 and 12 are located, is located approximately 0.5 m above the level nO corresponding to the upper surface of the sand bed.
• thermocouples 13 and 14 are at a level n2 above the level n1.
• the thermocouple 13 is located vertically of the injection nozzle 6 while the thermocouple 14 is located vertically of the injection nozzle 7.
• Level n2 is located higher in the post-combustion zone.
• Level n2 is about 2 m above level nO.
• thermocouples 15 and 16 are located in the upper part of the afterburner zone 4.
• thermocouple 17 is located at the level of the evacuation duct 1.
• the temperature sensors are connected to a PLC A constituting a means sensitive to the temperature difference between the sensors.
• the measurements from the various thermocouples are processed by the A controller, which is connected to the solenoid valves 8, 9 to control them.
• the controller A can emit an alarm to indicate the probability of a plugging of one of the two injection nozzles.
• the lowest temperature indicates the location of the capping. Indeed, if there is more introduction of the product in a nozzle, the temperature will quickly go down, and therefore the temperature measured by the sensor located vertically of said nozzle will be lower.
• the automaton A controls the closing of the valve 9, so as to direct the entire flow of sludge from the pump 10 common to the two nozzles 5, 6 ve rs the only nozzle 6 blocked, which will cause rapid its unblocking, without compromising in a global manner the flow injected into the oven.
• valve 9 At the end of a pre-set time, the valve 9 will be opened again to allow the return to normal operation.
• thermocouples 1 1 and 12 indicate a persistence of temperature difference, and therefore clogging at the end of the pre-set time, a second unclogging cycle is triggered.
• the second row of thermocouples 13 and 14 makes it possible, in the event of a malfunction, for example of one of the thermocouples of the first row of thermocouples 11, 12, to switch to automatic uncapping regulation using the thermocouples 13 and 14. It also allows to determine a second alarm level if the first row of thermocouples does not detect a difference in temperature while the second row detects one.
• the invention allows many possibilities and, in particular, is not limited to the management of two injectors.
• each of the nozzles comprising at least one thermocouple preferably located vertically above the sand bed.
• the temperature sensor associated with a sector is preferably located in the middle zone of this sector.
• Fig. 4 illustrates the case where four nozzles 6a, 6b, 7a, 7b are equally distributed over two opposite semicircular sectors S1 and S2, the sectors S1 and S2 being surmounted by the thermocouples, respectively 1 1 and 12.
• thermocouple 1 1 located vertically of the central zone of the sector S1 detects a temperature drop, and therefore a clogging
• the valves 9a and 9b supplying the nozzles 7a and 7b of the other sector S2 are temporarily closed while the valves 8a and 8b supplying the sector S1 are kept open.
• thermocouples After a first predetermined period of time, if the thermocouples do not indicate that the situation has returned to normal, the valves 8a and 8b are closed alternately to ensure the uncoupling.
• thermocouples are placed strictly above the nozzles or at a 45 ° angle (360/4/2) around the nozzles to control the action of each nozzle.
• the oven according to the invention also comprises provisions making it possible to minimize the risk of clogging the nozzles.
• This risk of clogging is mainly due to the fact that a small difference in pressure drop, on one of the injection lines from the discharge of the same pump, causes a decrease in flow in this line. This decrease in flow leads to a slight deposit which increases the pressure drop, which amplifies the decrease in flow, and ultimately leads to clogging.
• injection nozzles 6, 7 each have an inverted V shape, in particular frustoconical, with narrowing of the passage section to the outlet.
• Such a nozzle is provided to create a pressure drop at least equal to the maximum difference in pressure drop between the two injection lines from the same pump.
• the pressure drop created by the nozzles corresponding to 100% of the maximum possible difference in pressure drop between the two injection lines, makes it possible to reduce the relative influence of said pressure drop between lines.
• This pressure drop, created by the shape of the nozzles, allows to cover almost 100% of "inhomogeneities" of pressure loss.
• the oven according to the invention has many advantages. It allows on the one hand to minimize the clogging of one of the injection nozzles and on the other hand to automate the unclogging of the nozzles in the event of clogging and without having to multiply expensive equipment such as pumps. injection or without having to over-size them.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Environmental & Geological Engineering (AREA)
• Water Supply & Treatment (AREA)
• Incineration Of Waste (AREA)
• Fluidized-Bed Combustion And Resonant Combustion (AREA)

Applications Claiming Priority (2)

Publications (2)

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• 2013
  • 2013-08-27 FR FR1358199A patent/FR3010175B1/fr active Active
• 2014
  • 2014-08-26 WO PCT/IB2014/064060 patent/WO2015028933A1/fr active Application Filing
  • 2014-08-26 EP EP14786285.8A patent/EP3039338B1/de active Active
  • 2014-08-26 CN CN201480053378.6A patent/CN105593599B/zh active Active
  • 2014-08-26 ES ES14786285T patent/ES2762669T3/es active Active
  • 2014-08-26 PT PT147862858T patent/PT3039338T/pt unknown
• 2016
  • 2016-02-25 ZA ZA2016/01301A patent/ZA201601301B/en unknown

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