WO1996024008A1

WO1996024008A1 - Apparatus for heat treating a mass of material using a gaseous heat-transfer fluid

Info

Publication number: WO1996024008A1
Application number: PCT/FR1996/000169
Authority: WO
Inventors: Dominique Joseph Léon Victor BRACQ
Original assignee: Aquavir Systeme, S.A.
Priority date: 1995-02-02
Filing date: 1996-02-01
Publication date: 1996-08-08
Also published as: EP0807227A1; FR2730296B1; FR2730296A1

Abstract

An apparatus for heat treating a mass of material (2) using a gaseous heat-transfer fluid at a treatment temperature (T1), wherein the mass of material (2) to be treated is placed in a vessel (3) and exposed to the thermal activity of the heat-transfer fluid. Said apparatus includes a device (13) at least consisting of a burner (9A) with at least one means (12) for injecting a gas flow into the burner flame, said means being provided in a circuit for discharging the gaseous fluid flow to the atmosphere (A); and an exchange line (9E) receiving the gaseous fluid to be heated to the treatment temperature (T1) of the mass of material (2). The heating power values of the burner (9A) and the heat exchanging capacity value of the heat exchanger wall (9F) are such that the device (13) is at least sufficient to cause the desired thermal decomposition and to heat the gaseous fluid to the maximum treatment temperature.

Description

The invention relates to an installation for the thermal treatment of a mass of material by means of a gaseous heat transfer fluid.

The invention is generally applicable to any installation g i, discharging gaseous effluents, uses at least one gaseous fluid heated to a determined temperature.

The invention applies more particularly, but not exclusively, to a cooking-dehydration installation of materials which contain water and are sensitive to heat. Such an installation is described in patent FR-A-2,593,091, entitled "process for the treatment of organic waste with thermal degradation of smelly impurities and installation for the implementation of this process". The gaseous fluid used in the installation for the implementation in this process is air.

According to the technique of the prior art, the mass of material to be treated is placed in a tank, so as to be subjected to the thermal action of the gaseous heat transfer fluid and this, directly when said fluid is, by means of injectors, blown into said mass and / or indirectly, when the said fluid is channeled to circulate in a double envelope, the tank of which is drained.

The processing temperature of the mass of material depends on the nature of said material and can vary during the cycle, in particular passing through a maximum value.

Still according to this technique, the tank being equipped with separate discharge openings, for the evacuation of the gaseous fluid originating from the mass of material and from the double wall of the tank:

- On the one hand, the gaseous fluid directly from the mass of the material, is taken up to be separated from the vapors and particles which it has entrained, then it is reheated to the treatment temperature so as to be recycled into the heating the mass of material to be treated and,

- On the other hand, the gaseous fluid from the double jacket of the tank is, guant à lui, evacuated to the atmosphere. Typically, the heating of the gaseous fluid from the interior of the tank and then its reheating after treatment is carried out by passage in contact with a flame of a burner.

In order to prevent the malodorous components which are present during the passage of the material, can be destroyed during the reheating of the gaseous fluid, a special burner (FR-A-2,556,446) has been studied and produced.

Mistletoe installations, operating according to the method announced above, use the aforementioned burner, have their advantages, but they are criticized in particular for imperfectly treating the smelly components.

To overcome such a drawback, it is known to use an additional burner, in leguel the fluid directed to the atmosphere is incinerated, prior to its discharge. To be effective, this incineration must be carried out at a temperature of at least eight hundred degree degrees (850 °), with a transit time of several seconds, this mistletoe is very expensive from the point of view of the energy consumed.

The installation thus equipped is no longer satisfactory in terms of energy balance.

A result which the invention aims to obtain is precisely an installation which overcomes the disadvantages announced.

To this end, the subject of the invention is an installation of the aforementioned type, in particular characterized in that it comprises a device consisting of at least:

- A burner, of a determined heat production power, comprising, defined by at least one wall, at least one primary, secondary chamber intended to receive a gaseous mass, such as the flame that it produces during its operation, this burner being equipped with at least one means which is said to inject a gaseous flow into its flame, is interposed on the circuit for rejecting the flow of gaseous fluid into the atmosphere, so as to inject this fluid into said flame before the discharge to the atmosphere, of the gaseous mass produced, and

- a mistletoe duct, called an exchange, does not communicate with the interior of the burner but, is constituted by a mistletoe wall, at least locally common to this burner, on the one hand, ensures heat exchange with the gas mass produced in said burner and has a determined heat exchange capacity and, on the other hand, receives the gaseous fluid to be heated to the processing temperature of the mass of material, the leguel fluid circulates there with a certain flow,

- the values of the heat production power inherent in the burner and the values of the heat exchange capacity specific to the wall mistletoe, called heat exchange, is common to this burner and to the gaseous fluid circulation duct, are such that the device is at least sufficient for:

. on the one hand, ensuring the thermal degradation sought on the components injected into the burner flame and,

- on the other hand, bring the gaseous fluid, the flow of which passes through the exchange duct, to the maximum treatment temperature, taking into account the flow rate imposed on this gaseous flow for its circulation in said exchange duct and then in the circuit first supply of the tank.

The invention will be better understood with the aid of the description below given by way of nonlimiting example with regard to the appended drawing which shows diagrammatically:

FIG. 1: an installation according to the invention,

- Figure 2: a partially cutaway perspective view of a means used in the installation. Referring to the drawing, there is shown an installation 1 for heat treatment of a mass of material 2 by means of a gaseous heat transfer fluid (not shown), previously brought to a temperature T1, called the treatment temperature.

The process during duguel the mass of material 2 is treated thermally, is called treatment cycle.

The temperature Tl for processing the mass of material 2 can obviously change during the treatment cycle and, in particular, pass through a maximum value.

A maximum duration of the treatment cycle can also be imposed by the user of the installation and therefore constitutes a parameter for calculating this installation. For example, the installation 1 is a cooking-dehydration installation of materials 2 mistletoe, containing water, are sensitive to heat.

Although this does not appear in the drawing, the gaseous fluid used in the installation 1 is advantageously air.

In this installation 1, the mass of material 2 to be treated is placed in a tank 3 so as to be subjected to the thermal action of the heat transfer fluid, and this, in at least one of the two ways which are: so-called direct manner, when said fluid is, by means of injectors 4, blown into said mass of material 2 so that it passes through it, and

- A so-called indirect way, when the said fluid is channeled to circulate in a double envelope 5 whose tank 3 is cleaned.

Also in this installation 1:

- in addition to a first circuit 6 which channels the gaseous fluid at an adequate temperature towards it, the tank 3 is provided with at least one of the two separate evacuation circuits 7, 8 which are:

. on the one hand, a second circuit 7 for the evacuation of a gaseous fluid Gl directly coming from the mass of material 2,

. on the other hand, a third circuit 8 for the evacuation of a gaseous fluid G2 coming from the double jacket 5 of the tank 3 and,

- At least one 7 of these second and third circuits 7, 8 is connected to a means 9 of heating to the temperature Tl for processing the mass of material 2, and this with a view to recycling the gaseous fluid involved in the heating of this mass, via the first circuit 6 and the other circuit 8 leads to him at atmosphere A.

The gaseous fluid is displaced in the various circuits 6, 7, 8 by the implementation of at least one circulation fan V, leguel therefore requires a flow of gaseous fluid in each of the circuits of the installation 1.

If necessary, the gaseous fluid directed towards the means 9 for heating to the treatment temperature passes through beforehand means 10A, 10B for purification, such as means for separating the vapors and particles which it contains.

The gaseous fluid discharged to the atmosphere A first passes through a means 11 of heating to a temperature T2 of degradation of odorous compounds which it may contain.

As it appears in the drawing, the means 11 for heating to a temperature T2 called "degradation of odorous compounds" consists of a burner in the flame F duguel the gaseous fluid to be treated, such as the fluid G2 from the double jacket 5 of the tank 3 is introduced.

Remarkably, instead of including a means 9 for heating the gaseous fluid to the treatment temperature which essentially consists of a burner in contact with the flame F duguel, the gaseous fluid to be heated to the treatment temperature Tl is brought:

the installation 1 comprises a device 13 consisting of at least:

. a burner 9A, of a determined heat production power, comprising, defined by at least one wall 9B, at least one primary chamber 9C, secondary 9D intended to receive a gaseous mass M, such as the flame F which it produces during its operation, this burner 9A being equipped with at least one means 12 mistletoe, said to inject a gaseous flow into its flame, is interposed on the circuit for rejecting the flow of gaseous fluid in the atmosphere, so as to produce injecting this fluid into said flame F before rejection to the atmosphere A, of the produced gaseous mass M,

. a conduit 9E mistletoe, said to exchange, does not communicate with the interior of the burner 9A but, is constituted by a wall 9F mistletoe, at least locally common to this burner 9A, on the one hand, ensures the thermal exchange with the gaseous mass M produced in said burner 9A and has a determined heat exchange capacity and, on the other hand, receives the gaseous fluid to be heated to the temperature Tl for processing the mass of material 2, the legual fluid circulates therein with a certain flow,

the values of the heat production power inherent in the burner 9A and the values of the heat exchange capacity specific to the wall 9F mistletoe, called heat exchange, is common to this burner 9A and to the conduit 9E for circulation of the gaseous fluid, such that the device 13 is at least sufficient for:

. on the one hand, ensuring the thermal degradation sought on the components injected into the flame F of the burner 9A and,

. on the other hand, bring the gaseous fluid, the flow of which passes through the exchange conduit 9E, to the maximum treatment temperature, taking into account the flow rate imposed on this gaseous flow for its circulation in said exchange conduit 9E then in the circuit 6 first supply to the tank 4.

It is essentially by respecting these technical characteristics that the main result of the invention is obtained.

In the installation 1 shown in the drawing, the tank 3 is provided with separate evacuation circuits 7, 8 for evacuation:

- On the one hand, a gaseous fluid G1 directly coming from the mass of the material 2, towards means 9, 10A, 10B of purification then, of heating (9) at the temperature of treatment of the mass of material 2 and,

- on the other hand, a gaseous fluid G2 from the double jacket 5 of the tank 3 is, guant à lui, evacuated to the atmosphere A, and this, after passage through a heating means 11 at a temperature T2 of degradation of odorous compounds whose presence results, in particular, from the crossing of the mass of material 2.

In this installation 1:

it is the gaseous fluid Gl directly coming from the mass of material 2 mistletoe, downstream of the purification means 10A, 10B, is channeled in the duct 9E for exchanging the heating device 13 and,

- It is the gaseous fluid G2 from the double jacket 5 of the tank 3, mistletoe is channeled in the means 12 for injection into the flame F of the burner 9A of the heating device 13. Remarkably, the installation includes:

a first member 14 for controlling the passage of a gaseous fluid mistletoe is located on the evacuation circuit of the gas flow Gl directly coming from the tank 4, a second member 15 for controlling the passage of a gaseous fluid mistletoe is located upstream of the injectors 4,

- an additional pipe 16 mistletoe establishes a connection between, on the one hand, a part of the tank 3 mistletoe extends above the mass of material 2 to be treated and, on the other hand, the means 12 for injecting a gas flow in the flame F of the burner 9A of the heating device 13,

- disposed on this annex pipe 16, a third member 17 for controlling the passage of the fluid in this annex pipe 16.

These technical features allow:

- On the one hand, by closing the said first, second and third organs 14, 15, 17, to isolate the part of the tank 3 containing the mass of material to be treated so as to allow, in particular, a rise in pressure of its internal volume, following the heating of the mass of material via the passage through the double jacket 5 of this tank 3 by a gaseous fluid brought to an adequate temperature and,

- on the other hand, gu'at least at the end of such a heating step, a gaseous mass produced during this step, can, by the opening of said third member 17, be evacuated to the atmosphere after treatment thermigue at the temperature T2 of thermal degradation of odorous compounds which it contains. Still remarkably, the installation includes:

a bypass pipe 18 which establishes a connection between, on the one hand, the upstream of said second member 15 for controlling the passage of the fluid towards the injectors 4 and, on the other hand, the upstream of the exchange duct 9E of the heating device 13, - disposed on this bypass pipe 18, a second member 19 for controlling the passage of the fluid in this pipe 18,

- An atmospheric air intake pipe 20 connected upstream of the duct 9E for exchanging the heating device 13 and, disposed on this pipe, a cinguième organ 21 for controlling the passage of a gaseous fluid.

When the passage of gaseous fluid is interrupted towards the injectors 4 but authorized in the bypass line 18 which establishes a connection between, on the one hand, the upstream of the second member 15 for controlling the passage of the fluid towards these injectors 4 and, on the other hand, the upstream of the duct 9E for exchanging the heating device 13 : - a fluid recirculation can be established in the installation for heating the mass of material notwithstanding the evacuation to the means 11 of thermal degradation, of part of said fluid.

By control member for the passage of the fluid is meant a member which allows at least all-or-nothing control of the passage of the gaseous fluid in the pipe on the laguelle it is interposed.

Remarkably, the installation includes a means

22 annex for heating the gaseous fluid, and this means 22 consists of a burner 22A by direct heating with a flame, the conventional burner 22A is interposed between the heating device 13 and the tank 4.

This additional heating means 22 makes it possible to better manage the temperature of the gaseous fluid supplied to the tank 3. Preferably, the heating device 13 comprises:

- a primary mistletoe chamber 9C, substantially elongated and delimited by at least one wall 9B, is said to be of combustion and in laguelle are arranged:. the burner 9A in such a way that the flame F which it produces develops in a zone Z substantially axial to said primary chamber 9C,

. a plurality of ejection nozzles 12A of a gaseous fluid in the primary chamber 9C, the nozzles are, on the one hand, connected to a conduit 8A intended for the passage of the gaseous fluid to be evacuated to the atmosphere A after degradation of odorous compounds which it contains and, on the other hand, oriented to inject said fluid into the zone Z of development of the flame F so as to constitute the injection means 12,

- connected to the primary chamber 9C, so as to receive the gaseous mass M which is produced there, a secondary chamber 9D, called a retention chamber, having a volume at least sufficient to ensure the decompression of the gaseous mass M resulting from the mixture of the flame F and the gaseous fluid injected by the means 12 for this purpose, and this, by maintaining this mass M for a determined time at the degradation temperature T2 of the compounds fragrant,

- connected to the secondary chamber 9D, so as to receive the gaseous mass M which passes through it, a tertiary chamber 9G which houses at least one bundle 9E of conduits in order to constitute the conduit 9E for heat exchange with the gaseous mass M produced in the burner 9A, that is to say the pipe which receives the gaseous fluid to be heated to the treatment temperature T1 of the mass of material 2, and

- connected to the tertiary chamber 9G, so as to receive the gaseous mass M which passes through it, a pipe 8B for at least indirect evacuation of said gaseous mass M, towards the atmosphere A.

Preferably, the evacuation pipe 8B towards the atmosphere passes through at least one exchanger 23 for heating a fluid used in the operation of the installation, such as the combustion air of the burner 9A of the heating device 13.

In a preferred embodiment, the heating device 13 is formed in a box 24 that is substantially rectangular parallelepiped, the largest faces of which are substantially horizontal and which includes walls defining:

on the one hand, a higher volume 25 in the leguel constitutes the primary chambers 9C, 9D and secondary and

- On the other hand, a lower volume 26 in leguel is constituted the tertiary chamber 9G.

Compliance with these last technical features makes it possible to build a relatively compact heating device 13, the center of gravity of which is located at the bottom, due to the large mass which constitutes the presence of the bundles of conduits which form the conduit 'exchange.

Claims

1. Installation (1), on the one hand, for heat treatment of a mass of material (2), such as organic waste and, on the other hand, for thermal degradation of smelly impurities resulting from this treatment, and this by means of a gaseous heat transfer fluid, previously brought to a temperature (Tl), called treatment temperature in laguelle the mass of material

(2) to be treated is placed in a tank (3) so as to be subjected to the thermal action of the heat transfer fluid, and this, in at least one of the two ways which are:

- a so-called direct manner, when said fluid is, by means of injectors (4), blown into said mass of material (2) so that it passes through it, and - a so-called indirect manner, when said fluid is channeled to circulate in a double envelope (5) whose tank (3) is equipped, in this installation:

- in addition to a first circuit (6) which channels the gaseous fluid at an adequate temperature towards it, the tank (3) being provided with at least one of the two separate evacuation circuits (7, 8) which are:

. on the one hand, a second circuit (7) for the evacuation of a gaseous fluid (Gl) directly coming from the mass of material (2),

. on the other hand, a third circuit (8) for the evacuation of a gaseous fluid (G2) coming from the double envelope (5) of the tank (3) and,

- at least one (7) of these second and third circuits (7, 8) being connected to a means (9) of heating to the temperature

(Tl) for processing the mass of material (2), with a view to recycling the gaseous fluid involved in the heating of this mass, via the first circuit (6) and the other circuit (8) leads to it to the atmosphere (A), the fluid discharged to the atmosphere previously passing through a means (11) for heating to a temperature (T2) for degrading odorous compounds which it may contain, this means (11) comprising a burner ( 9A), this installation being CHARACTERIZED in that it comprises a device (13) which itself includes:

- a primary chamber (9C) mistletoe, substantially elongated and delimited by at least one wall (9B), is called combustion and in laguelle are arranged:

. the burner (9A), so that the flame (F) that it produces develops in a zone (Z) substantially axial to said primary chamber (9C),

. a plurality of ejection nozzles (12A) of a gaseous fluid in the primary chamber (9C), the nozzles are, on the one hand, connected to a conduit (8A) intended for the passage of the gaseous fluid to be evacuated to the atmosphere (A) after degradation of odorous compounds which it contains and, on the other hand, oriented to inject said fluid into the zone (Z) of flame development (F) so as to constitute a means (12) injection,

- connected to the primary chamber (9C), so as to receive the gaseous mass (M) which is produced there, a secondary chamber (9D), called retention, having a volume at least sufficient to ensure the decompression of the gaseous mass (M) resulting from the mixture of the flame (F) and the gaseous fluid injected by the means (12) for this purpose, and this, by maintaining this mass (M) for a determined time at the degradation temperature (T2) of the odorous compounds, - connected to the secondary chamber (9D), so as to receive the gaseous mass (M) which passes through it, a tertiary chamber (9G) which shelters at least one bundle (9E) of conduits in order to constitute a conduit (9E) for heat exchange with the gas mass (M) produced in the burner (9A), that is to say a duct which receives the gaseous fluid to be heated to the treatment temperature (Tl) of the mass of material ( 2), and

- connected to the tertiary chamber (9G), so as to receive the gas mass (M) which passes through it, a pipe (8B) for at least indirect evacuation of said gas mass (M), towards the atmosphere (A ).

2. Installation according to claim 1 comprising: - a burner (9A), of a determined heat production power,

- A conduit (9E) mistletoe, said exchange, does not communicate with the interior of the burner (9A) but, is constituted by a wall (9F) mistletoe, at least locally common to this burner (9A), of on the one hand, ensures thermal exchange with the gas mass (M) produced in said burner (9A) and has a determined heat exchange capacity and, on the other hand, receives the gaseous fluid to be heated to temperature (Tl) treatment of the mass of material (2), the leguel fluid circulates there with a certain flow, this installation being characterized in this way:

- the values of the heat production power inherent in the burner (9A) and the values of the heat exchange capacity specific to the wall (9F) which is known as heat exchange, is common to this burner (9A) and to the conduit (9E) for circulation of the gaseous fluid, such that the device (13) is at least sufficient for:

. on the one hand, ensuring the thermal degradation sought on the components injected into the flame (F) of the burner (9A) and,

- on the other hand, bringing the gaseous fluid, the flow of which passes through the exchange conduit (9E), to the maximum treatment temperature, taking into account the flow rate imposed on this gaseous flow for its circulation in said exchange conduit ( 9E) then in the circuit (6) first supply of the tank (4).

3. Installation according to claim 1 or 2 characterized in that it comprises:

a first member (14) for controlling the passage of a gaseous fluid mistletoe is located on the circuit for evacuating the gas flow (Gl) directly coming from the tank (4),

a second member (15) for controlling the passage of a gaseous fluid mistletoe is located upstream of the injectors (4),

- an annex pipe (16) mistletoe establishes a connection between, on the one hand, a part of the tank (3) mistletoe extends above the mass of material (2) to be treated and, on the other hand, the means (12) for injecting a gas stream into the flame (F) of the burner (9A) of the heating device (13), - Arranged on this annex pipe (16), a third member (17) for controlling the passage of the fluid in this annex pipe (16).

4. Installation according to claim 3 characterized in that it comprises:

- a bypass pipe (19) which establishes a connection between, on the one hand, the upstream of said second member (15) for controlling the passage of the fluid towards the injectors (4) and, on the other hand, the upstream the duct (9E) for exchanging the heating device (13),

- disposed on this bypass pipe (19), a second member (18) for controlling the passage of the fluid in this pipe (19),

- an inlet pipe (20) for atmospheric air connected upstream of the duct (9E) for exchanging the heating device (13) and, disposed on this duct, a cinguième organ (21) for controlling the passage of 'a gaseous fluid.

5. Installation according to one guelcongue of claims 1 to 4 characterized in that it comprises a means (22) annex for heating the gaseous fluid, and this means (22) consists of a burner (22A) by direct heating to the flame, leguel burner (22A) is interposed between the heating device (13) and the tank (3).

6. Installation according to one guelcongue of claims 1 to 5 characterized in that the heating device (13) consists of a box (24) substantially parallelepipedal rectangle, the largest faces of which are substantially horizontal and which includes walls defining : - on the one hand, a higher volume (25) in leguel are constituted the primary (9C, 9D) and secondary chambers and,

- On the other hand, a lower volume (26) in leguel is constituted the tertiary chamber (9G).

7. Installation according to one guelcongue of claims 1 to 6, the tank (3) is provided with separate evacuation circuits (7, 8) for evacuation:

- on the one hand, a gaseous fluid (Gl) directly coming from the mass of the material (2), towards means (9, 10A, 10B) purification then heating (9) to the temperature of treatment of the mass of material (2) and,

- on the other hand, a gaseous fluid (G2) coming from the double envelope (5) of the tank (3) is, guant à lui, evacuated towards the atmosphere (A), and this, after passage in a means (11) of heating to a temperature (T2) of degradation of odorous compounds whose presence results, in particular, from the crossing of the mass of material (2), characterized in this way: - it is the gaseous fluid (Gl ) directly coming from the mass of material (2) which, downstream of the purification means (10A, 10B), is channeled in the conduit (9E) for exchange of the heating device (13) and,

- It is the gaseous fluid (G2) coming from the double envelope (5) of the tank (3), mistletoe is channeled in the means (12) of injection into the flame (F) of the burner (9A) of the device (13) heating.