WO2002084178A1

WO2002084178A1 - System and method for incinerating organic matter, especially animal meal and fat

Info

Publication number: WO2002084178A1
Application number: PCT/FR2002/001279
Authority: WO
Inventors: Raymond Guyomarc'h
Original assignee: Bio 3D Applications
Priority date: 2001-04-13
Filing date: 2002-04-12
Publication date: 2002-10-24
Also published as: FR2823555B1; FR2823555A1

Abstract

The invention relates to a system for incinerating organic matter, comprising a solid fuel oven comprising a grid receiving solid fuel and means for injecting oxygen, a thermolysis/pyrolysis column provided with grids which are inclined towards the oven, a supply of solid fuel to the oven and a supply of organic matter which is to be incinerated above said inclined grids, a homogenization chamber for combusted gases and organic vapors arising from the thermolysis/pyrolysis column, a combustion chamber followed by a post-combustion chamber, a heat exchanger for recovering the energy of the waste gases arising from the post-combustion chamber, and a combustion gas extractor at the exit of the heat exchanger.

Description

"System and process for the incineration of organic matter, in particular animal meal and fat"

The present invention relates to an organic matter incineration system, in particular meal and fat of animal origin. It also relates to an incineration process implemented in this system.

The elimination of organic matter, especially from animal production and the food industry, is a major problem for businesses and communities. This is indeed to ensure that all of the pathogenic structures possibly contained in these organic materials are destroyed for obvious reasons of public health.

Techniques for the incineration of organic materials already exist, but most of the current methods have the disadvantage of discharging into the environment compounds with high toxicity such as dioxin or furans. In addition, these incineration processes consume a lot of energy and have a negative impact on the environment. Document JP1 1 3041 1 7A2 effectively discloses an animal carcass incineration system without generation of dioxin, comprising a primary combustion chamber equipped with a burner, a secondary combustion chamber disposed above the primary combustion chamber , a stabilizer for accumulating heat to generate radiant heat and a high temperature air vortex, and a smoke suppression burner for heating with flames at high temperature the interior space of the combustion chamber secondary which is in continuity with the primary combustion chamber and the stabilizer. The secondary combustion chamber suppresses the generation of dioxin by completely burning the unburned gases leaving the primary combustion chamber. Such However, the system has the disadvantage of requiring a substantial supply of fuel for the two burners.

The aim of the present invention is to remedy these drawbacks by proposing an organic matter incineration system which at the same time guarantees the complete destruction of all organic compounds, in particular proteins and viruses, while being part of a process environmentally friendly and energy efficient.

This objective is achieved with an incinerator system comprising:

- a solid fuel oven comprising a grid receiving a solid fuel and means for injecting oxygen,

- a thermolysis / pyrolysis column comprising grates inclined towards the furnace, means for bringing solid fuel to the level of the furnace and means for bringing organic matter to be incinerated above said inclined grids, - a gas homogenization chamber burns and organic vapors from the thermolysis / pyrolysis column,

- a combustion chamber followed by a post-combustion chamber,

- heat exchange means for recovering the energy of the exhaust gases from the post-combustion chamber, and - means for extracting combustion gases at the outlet of the heat exchange means.

The solid fuel advantageously consists of densified ligno-fibro-cellulosic plant biomass. This fuel is notably distributed under the name [Bio-D] and is described in document FR2790403.

In a preferred embodiment, the oxygen injection means comprise primary oxygen injection means under the oven rack, and secondary oxygen injection means at the heart of a bed of embers produced above the oven rack with solid fuel in combustion. The incinerator system according to the invention also preferably comprises means for controlling the supply of solid fuel so as to prevent any entry of parasitic air into the furnace, means for controlling the atmosphere within the thermolysis column. / pyrolysis so as to be without residual oxygen, means for controlling the speed of the gases and / or their temperature to allow the thermal acquisition required for the vaporization of the gasifiable organic matter, means for controlling the supply of organic matter so avoid any unwanted entry of air. In a preferred embodiment of an incinerator system according to the invention, the combustion chamber is cylindrical and has a parabolic bottom open on the gas nozzle, of diameter smaller than that of said combustion chamber, and provided with a central cone directed towards said nozzle. The post-combustion chamber is also cylindrical and has in its axis a tube to support the parabolic bottom of the combustion chamber.

According to another aspect of the invention, there is provided a method for incinerating organic matter, characterized in that it comprises:

- production of thermal energy required for thermolysis and pyrolytic reduction of organic matter within a thermolysis / pyrolysis column, by combustion of a solid fuel under oxygen,

a volatilization of the gasifiable components of said organic matter along the thermolysis / pyrolysis column, a combustion of the non-gasified organic compounds on a bed of embers resulting from the combustion of solid fuel,

- homogenization of the pyrolysis and solid fuel combustion gases in a mixing chamber,

an injection of oxygen into said pyrolysis and combustion gases to allow them to self-ignite, - injection of an ignited gas mixture into a combustion chamber,

- expansion of the burnt gases in a controlled post-combustion chamber, and - recovery of thermal energy at the outlet of the burnt gases.

As part of a complete ecological operation, the elements from the incinerator system according to the invention are concentrable and recoverable. The elimination of animal meal is therefore carried out without any rejection, the ashes themselves being usable. Carbon dioxide CO ₂ is a product consumed industrially and its recovery is therefore possible.

Cogeneration of energy ensures the profitability of the incineration process according to the invention by providing the heat necessary for the preparation of the preparations and the electricity which can be marketed.

In the case where the incineration of organic materials is carried out directly on the site of production of these materials, for example on a rendering site, the energy produced by cogeneration can then be directly consumed on this site. The incineration system according to the invention has the major advantage of using a solid and renewable fuel, solely composed of carbon, as basic energy, for the reduction and incineration of organic matter. This fuel is particularly suitable for combustion under oxygen, which allows an ignition of the solid fuel in hyper-oxidation for a drastic control of combustion and of the temperature, and a pyrolysis / thermolysis, in the gasification column, under control of absence of residual oxygen.

The use of oxygen as oxidizer makes it possible to rationalize the control and the adjustment of the stages of the incineration process according to the invention. Otherwise ; the implementation of this process allows a significant production of thermal energy and cogeneration of energy reinforced by the regularity of the thermal energy produced.

In addition, with the incineration process according to the invention, it is impossible to cause the formation of dioxins, furans and other compound molecules, polluting in the absence of elements contributing to it. The incineration system according to the invention can be used punctually or continuously.

Another advantage of the incineration system according to the invention is that it concentrates all of the thermolysis / pyrolysis, incineration, gas combustion and energy recovery operations. The use of oxygen as an oxidizer allows this concentration by limiting the interior volumes of the system. This results in a reduced footprint for greater operating capacity compared to current incineration processes. In addition, the concentration of carbon dioxide by cryogenization contributes to the suppression of carbon dioxide emissions in the atmosphere. The investment of the cryogenization unit can be amortized by the production of oxygen at the place of consumption and by the industrial recovery of liquid carbon dioxide. Other advantages and characteristics of the invention will appear on examining the detailed description of a mode of implementation in no way limiting, and the appended drawings in which: - Figure 1 is a block diagram of a system d incineration according to the invention, and - Figure 2 illustrates the essential phases of the incineration process according to the invention.

We will now describe, with reference to FIG. 1, an embodiment of an incineration system according to the invention.

The incineration system S according to the invention comprises: - a solid fuel furnace 1 with upward flow comprising a grid 1 0 receiving a solid fuel and oxygen injectors 1 1, - a thermolysis / pyrolysis column 2,

a chamber 3 for homogenizing the burnt gases and organic vapors, terminated by a nozzle 30 proportional to the required flow rates,

a cylindrical combustion chamber 4 having a parabolic bottom 30 open on the gas nozzle 31 and comprising in opposition a parabola 40, of a diameter smaller than the cylinder, with a central cone 41,

a cylindrical post-combustion chamber 5, expanded, comprising in its axis a support tube 50 of the parabola 40,

a heat exchanger 6 recovering the energy of the exhaust gases, connected to an energy cogeneration unit 9,

- a combustion gas extractor 7, the system operating under vacuum.

The oven 1 has in its lower part the grid 10 under which is disposed an ashtray 1 3, and above its upper part, a fuel supply chute 25.

The oxygen injection is carried out in primary under the grid, and in secondary in the heart of the bed of embers. This gives a very reactive magma, easily controllable.

The oven 1 is made of special steel to allow very high temperatures greater than or equal to 1600 ° C to be obtained.

Under the grate 10, the ashtray 1 3, airtight, receives the non-combustible residues C, ashes composed essentially of the non-combustible minerals contained in the organic materials, and of the minerals contained in the solid fuel for less 1% in quantity.

The walls of the oven 1, its grid 1 0 and the walls of the ashtray 1 3 are hydraulically cooled. The air-tight fuel supply chute 25 is placed above the furnace 1, with a continuous supply controlled so as to avoid any entry of parasitic air. The thermolysis / pyrolysis column 2 comprises: a parallelepiped 26 of height adapted to the desired thermal acquisition,

- tubular grids 21, 22, 23 inclined towards the furnace and composed of perforated tubes, - a supply 25 of densified biomass, at the furnace level,

- A supply 24 of organic matter to be incinerated above the grids.

In this column 2, the atmosphere is controlled so as to be without residual oxygen. The speed of the combustion gases and their temperature are controlled to allow the thermal acquisition required for the vaporization of gasifiable organic matter.

A fraction of the solid fuel is injected 26 into the flow of organic matter to be incinerated, which facilitates their flow and the permanent unclogging of the grids of the column 2. The homogenization chamber 3 is configured so as to direct the gases from the thermolysis / pyrolysis column to the combustion chamber 4, through the nozzle 30 at the level of which an oxygen injector 31 is arranged.

In the combustion chamber 4, of cylindrical shape, the cylinder of ignited gases coming from the nozzle 31 is split due to the arrangement of the cone 41 and the flames are put into turbulence by the presence of the parabola 40, the burnt gases then being evacuated through the passage between the periphery of the parabola and the cylindrical wall of the combustion chamber. The support tube 50 of the parabola 40 and of the cone 41 is hydraulically cooled.

The cylindrical post-combustion chamber 5 has, at its outlet end, exhaust pipes for the burnt gases, which are hydraulically cooled. The atmosphere of this chamber is controlled in composition, temperature, pressure and speed, so as to have no residual oxygen at the outlet of the exhaust gases. The walls of the cylindrical post-combustion chamber 5 which are in contact with the gas in ignition under oxygen are made of special steel.

The exhaust gases recovered in the heat exchanger 6 are essentially composed of carbon dioxide C0 ₂ and water H ₂ 0, taking into account the composition of organic matter and solid fuel.

We will now describe, with reference to FIG. 2, the incineration process according to the invention, the principle of which is to minimize, by thermal effects, the organic compounds to be eliminated, with a high gasifiable proportion. The main steps of the incineration process according to the invention include:

- a production (I) of the thermal energy required for thermolysis and pyrolitic reduction (II) of organic matter, by burning solid fuel on a low grate, under oxygen, - volatilization (IV) of the gasifiable components while along the thermolysis / pyrolysis column without oxygen available,

- completion of the combustion (III) of the non-carbonated organic compounds on a bed of embers,

a homogenization (V) of the pyrolysis and combustion gases of the solid fuel in a mixing chamber, an injection (VI) of oxygen in said pyrolysis and combustion gases, at the outlet of a nozzle, to allow their autoignition

an injection of the gaseous mixture thus obtained and a combustion (VII) of this mixture in a combustion chamber, in a cylinder of ignited gases, an expansion (VIII) of the gases burned in a controlled post-combustion chamber, and

- recovery (IX) of the thermal energy at the outlet of the burnt gases. Regarding the production of thermal energy required for thermolysis and pyrolytic reduction, the use of oxygen as an oxidizer allows high temperatures guaranteeing effective pyrolysis. Parasitic cooling due to nitrogen in the air and the risk of nitrogen oxide production are avoided. In addition, combustion under oxygen is more reliable, both in terms of temperature regulation and for obtaining perfectly stoichiometric combustion.

During the volatilization of the gasifiable components, the oxidizing oxygen is completely consumed by the ember bed M of the solid fuel in ignition and the combustible organic matters which are not gasifiable. This combustion control can only be carried out with assurance under oxygen.

In the combustion phase of the gas mixture in the combustion chamber 4, the cylinder of ignited gases is exploded on the cone 41 of the combustion chamber. Reflected by the parabola 40 along the outer walls of the chamber 4, the flames cause turbulence conducive to the complete combustion of the mixture. The burnt gases are exhausted through the peripheral space of the parabola 40.

The expansion of the burnt gases on the rear of the parabola 40 in the controlled post-combustion chamber 5 is carried out so as to have only carbon dioxide CO ₂ and water H ₂ 0 at the outlet and to control the absence of oxygen O ₂ .

The recovery of thermal energy at the outlet of the burnt gases can be carried out with existing known recovery systems.

Of course, the invention is not limited to the examples which have just been described and numerous modifications can be made to these examples without departing from the scope of the invention. The incineration system according to the invention can thus be manufactured with any size, and can be installed in a battery. This system can be integrated into any size of animal organic material processing unit while respecting the environment and with a guarantee of destruction of any harmful element.

Claims

1. System (S) for incinerating organic matter, characterized in that it comprises:

- a solid fuel oven (1) comprising a grid (10) receiving a solid fuel and means for injecting oxygen,

- a thermolysis / pyrolysis column (2) comprising grids (21, 22, 23) inclined towards the oven, means (25) for bringing solid fuel to the level of the oven and means (26) for bringing organic matter to be incinerated above said inclined grids,

- a homogenization chamber (3) of the burnt gases and organic vapors from the thermolysis / pyrolysis column (2),

- a combustion chamber (4) followed by an after-combustion chamber (5),

- heat exchange means (6) for recovering the energy of the exhaust gases from the post-combustion chamber (5), and

- Means (7) for extracting combustion gases at the outlet of the heat exchange means.

2. Incinerator system (S) according to claim 1, characterized in that the solid fuel consists of ligno-fibro-cellulosic plant biomass densified.

3. System (S) according to one of claims 1 or 2, characterized in that the oxygen injection means comprise means (1 2) for primary oxygen injection under the oven rack.

4. System (S) according to claim 3, characterized in that the oxygen injection means further comprises means (1 1) of secondary oxygen injection in the heart of a bed of embers (M) produced above the grid (10) of the furnace (1) by solid fuel in combustion.

5. System (S) according to any one of the preceding claims, characterized in that it further comprises an ashtray (1 3) located under the grid (1 0) of the oven (1) for receiving non-combustible residues.

6. System according to claim 5, characterized in that it further comprises means for hydraulically cooling the walls and the rack of the oven.

7. System according to any one of the preceding claims, characterized in that it further comprises means for controlling the supply of solid fuel so as to avoid any entry of parasitic air into the furnace.

8. System according to any one of the preceding claims, characterized in that the inclined grids within the thermolysis / pyrolysis column are composed of perforated tubes.

9. System according to any one of the preceding claims, characterized in that it further comprises means for controlling the atmosphere within the thermolysis / pyrolysis column so as to be without residual oxygen.

10. System according to any one of the preceding claims, characterized in that it further comprises means for controlling the speed of the gases and / or their temperature to allow the thermal acquisition required for the vaporization of the gasifiable organic matter.

1 1. System according to any one of the preceding claims, characterized in that it further comprises means for controlling the supply of organic matter so as to avoid any parasitic entry of air.

1 2. System according to any one of the preceding claims, characterized in that the homogenization chamber is terminated by a gas nozzle.

1 3. System according to claim 1 2, characterized in that the combustion chamber is cylindrical and has a parabolic bottom open on the gas nozzle, of diameter smaller than that of said combustion chamber, and provided with a central cone directed towards said nozzle.

1 4. System according to claim 1 3, characterized in that the post-combustion chamber is cylindrical and comprises in its axis a tube for supporting the parabolic bottom of the combustion chamber.

1 5. System according to claim 14, characterized in that it further comprises means for cooling the support tube.

1 6. System according to any one of the preceding claims, characterized in that it further comprises means for controlling the atmosphere inside the post-combustion chamber.

1 7. Process for incinerating organic matter, characterized in that it comprises:

- production (I) of thermal energy required for thermolysis and pyrolytic reduction (II) of organic matter within a thermolysis / pyrolysis column, by combustion of a solid fuel under oxygen, - volatilization (IV ) gasifiable components of said organic matter along the thermolysis / pyrolysis column, - combustion (III) of non-gasified organic compounds on a bed of embers resulting from the combustion of solid fuel,

- homogenization (V) of the pyrolysis and combustion gases of the solid fuel in a mixing chamber, - an injection (VI) of oxygen into said pyrolysis and combustion gases to allow them to self-ignite,

- injection of an ignited gas mixture and combustion (VII) of this mixture in a combustion chamber,

- an expansion (VIII) of the burnt gases in a controlled post-combustion chamber, and

- recovery (IX) of the thermal energy at the outlet of the burnt gases.

1 8. Method according to claim 1 7, characterized in that the thermal energy required for thermolysis and pyrolytic reduction of organic matter is produced by burning densified ligno-fibro-cellulosic plant biomass.

1 9. Method according to one of claims 1 7 or 1 8, characterized in that the gas mixture is injected into the combustion chamber in the form of a cylinder of ignited gases which is exploded on a cone.

20. The method of claim 1 9, characterized in that flames resulting from the bursting of the flaming gas cylinder are refluxed by a parabola located at the base of the cone.

21. Method according to claim 20, characterized in that the exhaust of the burnt gases is effected by a peripheral space of the parabola.