FR2857732A1 - FUEL HEATING BOILER OF THE INDIVIDUALIZED ELEMENT TYPE - Google Patents

Abstract

The object of the invention relates to a fuel-fired heating boiler (2) of the type with individualized elements comprising: - a combustion chamber (3) of a fuel (2), - a means for allowing the fuel to be ignited , - means (11) for supplying a primary oxidizer to allow combustion and obtaining gas and fumes (F), - and a heat exchanger (40). According to the invention, the heating boiler comprises : - a grid (8) for recovering the fuel (2) to support a porous mat of said first fuel, - means (14) for supplying a secondary oxidizer between the pipe system (15) of the gases and fumes and the porous mattress, - a recovery chamber (17) rising in the vertical extension of the combustion chamber.

Description

The present invention relates to boilers intended to provide

rise in

  temperature of a coolant that can be used for various purposes and more generally in a space heating system.

  The object of the invention is more specifically a boiler capable of operating from a fuel of the type with individualized elements, such as particles or granules, of single or combined combustible materials such as, for example, plants, cardboard, wood, etc. A preferred application of the invention relates to the production of a boiler operating from wood particles.

  In a conventional manner, a wood-type heating boiler has a combustion hearth provided with a through hole for a wood-based fuel. Such a combustion chamber is equipped with a burner for igniting the fuel inside the combustion chamber.

  Such a boiler also comprises means for supplying a primary oxidant such as air to allow combustion and the production of gases and fumes. These gases and fumes are channeled to be conducted in a gas and smoke recovery chamber which is led to a heat exchanger between a circulation circuit of a heat transfer fluid and a flue gas circulation circuit.

  The main disadvantage of a wood-type heating boiler is its poor thermal efficiency. Also, the object of the invention is therefore to overcome this disadvantage by proposing a new fuel heating boiler of the type with individualized elements such as, in particular, wood particles, having an improved thermal efficiency.

  To achieve such an objective, the object of the invention relates to a fuel heating boiler of the type with individual elements comprising: - a combustion chamber provided with a discharge port of a fuel provided by supply means a means for enabling the fuel to be ignited inside the combustion chamber, means for supplying a primary oxidant to allow the combustion and obtaining of gases and fumes, and a system for channeling the fuel. gas and smoke, a chamber for recovering gases and fumes from the piping system, and a heat exchanger between a circulation circuit for a coolant and a circulation circuit for the gases and fumes coming from the chamber. recovery.

  According to the invention, the heating boiler comprises: a fuel recovery grid for supporting a porous mattress of said fuel; means for supplying a secondary oxidant between the gas and smoke channeling system and the porous mattress; to disturb the flow of gases and fumes, - a recovery chamber rising in the vertical extension of the combustion chamber.

  Another object of the invention is to provide treatment by calcination, incineration or combustion of waste in the general sense. The object of the invention thus finds application, for example, in the field of the incineration of waste of vegetable nature or of ordinary industrial nature such as for example pallets or cartons, and finds a particularly advantageous application for the treatment of excrement. of animals and in particular poultry droppings.

  According to this application, the heating boiler comprises feed means ensuring the supply of waste on the recovery grid.

  Advantageously, the supply means are fed by fuel supply means and waste supply means, these supply means being distinct.

  According to another characteristic of the invention, the combustion chamber comprises, below the recovery grid, ash extraction means controlled by a control unit.

  Advantageously, the ash extraction means are constituted by a motor member ensuring at least partly the retraction of the recovery grid.

  Preferably, the ash extraction means also comprise an ash removal means outside the home and from the recovery grid.

  According to an advantageous characteristic of embodiment, the control unit 5 also controls the means for igniting the porous mat and the waste and fuel supply means so as to ensure repeatedly, the realization of a control cycle comprising a step for igniting the waste and the fuel, a combustion step during which the waste and fuel supply means are regulated and an ash extraction step.

  Another object of the invention is to control the parameters of the gases and fumes produced during combustion in order to respect the environment. For this purpose, the gas and flue gas recovery chamber defines a circulation path whose length is adapted to allow a residence time of the gases and fumes between the inlet and the outlet, greater than or equal to 2 s, to a temperature at least 850 C. In this way, virtually all dioxins present in the gases and fumes are removed.

  Advantageously, the flow path of the gases and fumes is delimited by a chimney rising vertically in the extension of the combustion chamber 20 and provided with an inner ferrule defining internally an ascending circuit for gases and fumes and externally, a downward circuit for gases and fumes.

  According to another characteristic of the invention, the heat exchanger comprises a series of exchanger tubes extending parallel to each other vertically, being disposed between the shell and an outer shell and internally constituting a gas and smoke circulation circuit connected thereto. in the lower part, at the exit of the circulation path and in the upper part at an exit chamber.

  Preferably, the exchanger tubes constitute, by their walls, exchange capacities with a circulating circuit of a coolant contained between said exchanger tubes and concentric tubes and in a mixing chamber 30 through which the exchanger tubes pass.

  Advantageously, the outlet chamber comprises an outlet mouth equipped with a filter and in that the heat exchanger comprises at its lower part an extraction outlet for particles.

  Various other features appear from the description given below with reference to the accompanying drawings which show, by way of non-limiting examples, embodiments of the subject of the invention.

  Figure 1 is a sectional elevational view of a first embodiment of a heating boiler according to the invention.

  Figure 2 is a cross-sectional view taken substantially along the lines II-II of FIG. 1.

  Figure 3 is an elevational sectional view showing a second embodiment of a heating boiler according to the invention.

  As is more particularly apparent from Figs. 1 and 2, the object of the invention relates to a heating boiler 1 operating with a fuel 2 in the form of individualized elements such as particles or granules of solid materials. Preferably, these individualized elements are wood chips. Of course, these individualized fuel elements can be made of different materials such as paper or cardboard, for example.

  The heating boiler 1 comprises a combustion zone 3 delimited by a closed envelope 4 of refractory character. The combustion chamber 3 comprises a fuel discharge port 2 supplied via supply means 6 which, in the example illustrated, is constituted by means of a worm. Preferably, these supply means 6 are supplied with individualized elements 2 by supply means 7 such as a controlled spill hopper.

  According to the invention, the combustion chamber 3 is provided with a grill 8 for recovering the fuel 2, thus disposed below the level of the discharge orifice 5. The recovery grille 8 is adapted to support the fuel 2 in the form of a porous mattress M. The combustion chamber 3 is equipped with a not shown means for igniting the fuel inside the combustion chamber and in particular, the porous mattress M fuel. For example, such a means may be constituted by a burner of any type known per se or an electric heating element.

  The heating boiler 1 also comprises means 11 for supplying a primary oxidant such as air to allow the combustion and the production of gases and fumes represented by the letters F in FIG. 1. For example, these supply means 11 may be constituted by a fan 12 opening through a pipe 13 in a chamber 14 arranged below the recovery grid 8.

  According to an advantageous characteristic of the invention, the combustion chamber 3 10 is provided with means 15 for supplying a secondary oxidant between the porous mattress M and a ducting system 16 for the gases and fumes to a recovery chamber 17. The supply means 15 make it possible to disturb the upward trajectory of the gases and fumes F. For example, these supply means 15 consist of a ventilation means 18 making it possible to supply air to orifices 19 distributed at the periphery. the combustion chamber 3 according to a transverse cross section. These gases and fumes F are disturbed before being conducted to the pipe system 16 so as to contribute to their combustion. For example, the ducting system 16 is constituted by the upper part of the hearth 3 made in the form of a venturi. According to one characteristic of embodiment, these gases and fumes F are naturally conducted by ascending way to the recovery chamber 17 which rises in the vertical extension of the combustion chamber 3.

  According to a preferred example of application of the heating boiler according to the invention, to the treatment by combustion of waste, the feed means 6 also ensure the supply to the interior of the combustion chamber, waste intended for 25 to be poured on the recovery grid 8. Preferably, the feed means 6 are supplied with waste by supply means 21 such as a controlled spill hopper. Such waste occurs naturally or as a result of appropriate treatment in the form of individualized elements, particles or granules. This waste may consist of forest products, for example from pruning or by cartons or pallets previously treated by a mill associated or not with the heating boiler. According to a preferred application, the waste consists of poultry manure combined with or not other products such as wood chips.

  The waste 20 as well as the fuel 2 are thus discharged above the grid 8 which thus supports a mattress consisting of a mixture of fuel and waste. It thus establishes a kind of porous mattress M a few centimeters thick which is ignited by the burner.

  According to another embodiment of the invention, the combustion chamber 3 comprises, below the recovery grille 8, means 30 for extracting the ashes controlled by a control unit not shown. These ash removal means 30 are constituted by a motor member 31 acting via a transmission 32 to allow at least partial retraction of the recovery grid 8. In the example shown, the grid of recovery 8 is rotated to allow the ash to fall into the chamber 14 located below the combustion chamber 3. Preferably, the transmission 32 also rotates a scraper 34 for driving the ashes direction of a means of evacuation 36 ashes outside the home. In the illustrated example, this evacuation means 36 is constituted by means of an endless screw, driven in rotation also by the motor member 31.

  According to another characteristic of the invention, the heating boiler 1 comprises a heat exchanger 40 between a circulation circuit 41 of a coolant and a circulation circuit 42 of the gases and fumes coming from the recovery chamber 17. the illustrated example, the recovery chamber 17 is delimited internally by a ferrule 45 carried by the refractory hearth 3 for delimiting internally an upward path 17, for gases and fumes coming directly from the combustion chamber 3 and externally, a path down 172 for gases and fumes found in the lower part at the entrance of the circulation circuit 42 of the gases and fumes of the heat exchanger 40. The recovery chamber 17 and has a circulation path 171, 172 for the gas and flue gas between the combustion chamber 3 and the inlet of the heat exchanger 40.

  According to a preferred embodiment, the heat exchanger 40 comprises a series of exchanger tubes 50, extending parallel to each other vertically, being arranged between the shell 45 and an outer shell 51. As is more particularly apparent from FIG. . 2, the exchanger tubes 50 are arranged on a circular circumference. The flue gas circulation circuit 42 is thus connected at the inlet to its lower part, at the outlet of the circulation path 172 of the recovery chamber 17 and at the top, to an outlet chamber 55 into which the tubes open. exchangers 50.

  Preferably, the outlet chamber 55 comprises an outlet mouth equipped with a filter. Similarly, the heat exchanger 40 comprises at its lower part, an extraction outlet for particles from the gases and fumes.

  The exchanger tubes 50 constitute, by their walls, exchange capacities with the circulation circuit 41 of a coolant contained between said exchanger tubes 50 and concentric tubes 57. The exchanger fluid contained between the exchanger tubes 50 and the concentric tubes 57, communicates with a mixing chamber 60 arranged in the upper part of the heating boiler and traversed by the heat exchanger tubes 50.

  For the advantageous application of the heating boiler to the treatment of waste 20, the recovery chamber 17 of gases and fumes delimits a circulation path 171, 172 whose length is adapted to allow a residence time of gases and fumes between the inlet and outlet, greater than or equal to 2 s and a temperature of at least 850 C. It should be understood that the travel time of the gases and fumes in the circulation path 171, 172 must be equal to at least at 2 s.

  Such an arrangement makes it possible to ensure that practically all the dioxins present in the gases and fumes are burned. According to this exemplary embodiment illustrated more specifically in FIG. 3, the flow path of the gases and fumes is delimited by a chimney 61 rising vertically in the extension of the combustion chamber 3. This chimney 61 is provided with an inner ferrule 45 internally defining the upward path 17, for gases and fumes. This inner ferrule 45 is mounted inside and at a distance from a concentric liner 62 defining between them the downward path 172 for gases and fumes. This chimney 61 is provided with a dome 63 extending the liner 62 to close the liner. chimney at its upper part to allow the change of direction of gases and fumes. Insofar as the upstream 17 and down 172 paths extend on either side of the ferrule 45, the gases and fumes retain, during this path, a high temperature of at least 850 C.

  According to another preferred embodiment, the control unit controlling the ash extraction means 30 also controls the means for igniting the porous mat M and the supply means 21, 7 in waste 20 and in fuel 2. This control unit makes it possible repeatedly to carry out a control cycle comprising a step for igniting the waste 20 and the fuel 2, a combustion step during which the waste supply means 21 and the means 10 of supply 7 of fuel 2 are regulated so as to obtain a sufficient temperature in the combustion chamber 3 and adapted to the energy available for the heating boiler. This combustion step is followed by an ash extraction step during which the ash extraction means 30 are controlled. Such a control cycle is thus regularly repeated depending on the thermal demand and the fuel and waste inputs.

  The invention is not limited to the examples described and shown because various modifications can be made without departing from its scope.

Claims (11)

  1 - Fuel heating boiler (2) of the type with individual elements comprising: - a combustion chamber (3) provided with a discharge orifice (5) for a fuel (2) supplied by supply means ( 6), - a means for enabling the fuel to ignite inside the combustion chamber (3), - means (11) for supplying a primary oxidant to allow the combustion and obtaining of gases and fumes (F), - a pipe system (16) for gases and fumes, - a recovery chamber (17) for gases and fumes coming from the pipe system, - and a heat exchanger (40) between a circulation circuit ( 41) of a coolant and a circulation circuit (42) of gases and fumes from the recovery chamber (17), characterized in that it comprises - a grate (8) for recovering the fuel (2) for supporting a porous mattress of said first fuel, - means (15) for supplying a secondary oxidant in the system 20 for channeling (16) gases and fumes and the porous mattress to disrupt the flow of gases and fumes, - a recovery chamber (17) rising in the vertical extension of the combustion chamber.   2- heating boiler according to claim 1, characterized in that the feed means (6) ensure the supply of waste (20) on the recovery grid (8).   3- heating boiler according to claim 2, characterized in that the supply means (6) are fed by supply means (7) for fuel (2) and waste supply means (21) ( 20), these supply means (21, 7) being distinct.   4- boiler according to claim 1 or 2, characterized in that the combustion chamber (3) comprises below the recovery grid (8), means (30) for extracting ashes controlled by a control unit.   5- boiler according to claim 4, characterized in that the means 5 for extracting ash (30) are constituted by a motor member (31) ensuring at least partly the retraction of the recovery grid (8).   6. Boiler according to claim 4, characterized in that the ash extraction means (30) also comprise an ash removal means (36) outside the home and from the recovery grid.   7- boiler according to claim 4, characterized in that the control unit also controls the means for igniting the porous mat and the supply means (21, 7) waste (20) and fuel (2) so to ensure repeatedly, the realization of a control cycle comprising a step for igniting the waste and the fuel, a combustion step during which the waste and fuel supply means (21, 7) are regulated and an ash extraction step.   8- boiler according to claim 1, characterized in that the gas and flue gas recovery chamber (17) defines a circulation path (171, 172) whose length is adapted to allow a residence time of gases and fumes between 20 the inlet and the outlet, greater than or equal to 2 s, at a temperature of at least 850 C.   9- boiler according to claim 8, characterized in that the flow path of gases and fumes (171, 172) is defined by a chimney (61) rising vertically in the extension of the combustion chamber (3) and provided with an inner ferrule (45) internally defining an upward path (171) for gases and fumes and externally a downward path (172) for gases and fumes.   - boiler according to claims 1 and 8, characterized in that the heat exchanger (40) comprises a series of heat exchanger tubes (50) extending parallel to each other vertically being disposed between the ferrule (45) and an envelope 30 external (51) and internally constituting a flue gas circulation circuit (42) connected in the lower part to the outlet of the circulation path (17) and in the upper part to an outlet chamber (55).   11- Boiler according to claim 10, characterized in that the exchange tubes (50) constitute, by their walls, exchange capacities with a circulation circuit (41) of a heat transfer fluid contained between said exchange tubes (50) and concentric tubes (57) and in a mixing chamber (60) through which the exchanger tubes (50) pass.   12 - boiler according to claim 10, characterized in that the outlet chamber (55) comprises an outlet mouth equipped with a filter and in that the heat exchanger (40) comprises at its lower part an outlet of extraction for particles.