FR2865202A1 - Plant for treating industrial effluent has evaporator with steam and water outlets and incinerator for solid matter - Google Patents

Abstract

The plant has at least one inlet (2) for the effluent to be treated, an evaporator (6) for at least part of the water content, converting the effluent into steam and solids or paste material, with outlets (8, 10) for the steam and water, and an incinerator (14) for reducing the remaining solids or paste material into cinders. The incinerator is located beneath the evaporator so that surplus energy from the combustion of solids and paste material is used to evaporate the water. The liquid effluent is heated before it enters the evaporator by means of a heat exchanger (4) fed by the steam, with water condensed by the heat exchanger passing through outlet (10).

Description

1 2865202

  The present invention relates to the general field of industrial water treatment and solid waste, as well as the treatment of water and urban sludge and the production of drinking water by desalination of seawater or distillation of river water. It relates more particularly to a treatment plant for liquid or semi-liquid effluents (for example effluents from the pulp and paper industry), which can also handle solid waste.

  The existing liquid and solid effluent treatment techniques of the paper mill industries are based on mechanical dewatering of sludge (screw presses or band presses, centrifuges ...), chemical precipitation or incineration in boilers. bark.

  The other known systems rely on the use of primary energies (gas and oil), and consist of thermal drying plants, thermal reactors, pyrolysis furnaces or incinerators.

  These various conventional techniques involve complex means and / or are very expensive.

  The present invention proposes a new installation structure that is simple and inexpensive to implement, that can be used effectively for the treatment of liquid or semi-liquid effluents and possibly solid waste, which are generated by any type of industry. .

  According to the invention, this installation comprises: at least one inlet for the effluent to be treated; means capable of ensuring the evaporation of at least a portion of the water contained in this effluent, to ensure its transformation; in water vapor, on the one hand, and in solid or pasty waste, on the other hand, means for evacuation of water vapor or water generated by this water vapor, oven-shaped means for incinerating said solid or pasty waste in order to reduce it to ashes, which incinerator furnace is disposed under said evaporator means so as to use the combustion energy of said solid or pasty waste to ensure the aforementioned evaporation, and means for evacuating the ash generated by the aforementioned incineration.

  According to a particularly interesting characteristic, the installation comprises means for heating the liquid or semi-liquid effluent before entering the evaporator means.

  Preferably, the heating means in question consist of a heat exchanger fed by the steam generated by the evaporator means; in this frame, the plant advantageously comprises an outlet for the water coming from the cooling of the steam by the heat exchanger.

  According to another particularity, the installation comprises means ensuring the transfer of the heated effluent to the evaporation means. These transfer means advantageously consist of a pump system (s) and pipe (s).

  According to yet another particularity, the installation according to the invention comprises an incinerator furnace provided with at least one burner and at least one system for mixing solid waste and ashes.

  The corresponding stirring system advantageously consists of a mixer 10 of the type with rotary blades of vertical axis, associated with a system of evacuation of ashes in the form of a rotary valve.

  According to yet another particularity, the installation comprises at least one arrival for solid waste directly at the incineration furnace.

  According to another particularly interesting characteristic, the incinerator means are associated with a thermal oxidation chamber of gases and fumes generated by the combustion of solids.

  Preferably, the installation comprises means for evacuating the fly ash from the oxidation chamber.

  According to yet another particularity, the installation comprises means which make it possible to send the hot air coming from the oxidation chamber towards the evaporator means.

  According to another characteristic, the installation comprises a solid or semi-solid waste recovery system from the evaporator means, adapted to allow the transfer of said waste either towards the incineration furnace, or outwardly.

  According to yet another particularity, the incineration furnace comprises - a first mixer arranged beneath a first burner, near the outlet of the evaporator means, an arrival of solid waste being provided at said first mixer, and - a second mixer arranged beneath a second burner, a complementary arrival of solid waste being provided at said second mixer.

  According to a particularly advantageous characteristic, the evaporator means consist of a plurality of horizontal or substantially horizontal tubes provided with an upstream opening and a downstream opening; these tubes are each connected to the effluent supply means at their opening 2865202 upstream, and they comprise means for driving the effluent towards their downstream opening.

  Preferably, the drive means in question consist of a longitudinal floating helical blade mounted on bearings and held by a plurality of longitudinal cables.

  The principle of the invention is based on the fact of treating more or less charged polluted water by evaporating all or at least the great majority of the water and by burning the residues, thus eliminating the waste transformed into pure water and in ashes. The fumes generated by the incineration of solid waste are treated by thermal oxidation.

  This system allows recovery of waste in the form of heat and hot water. It allows water, sludge and solid waste to be treated selectively. The water can be recycled permanently in the industrial process, possibly after a slight mineralization.

  This system allows a selective storage of ash and increases the possibilities of valorization of these ashes.

  But the invention will be further illustrated, without being limited in any way, by the following description of a particular embodiment, given solely by way of example and shown in the accompanying drawings, in which: FIG. 1 is a diagrammatic view of a treatment plant according to the invention; - Figure 2 is a schematic view in section along 2-2 of Figure 1; - Figure 3 is a schematic view in section along 3-3 of Figure 1; FIG. 4 is a diagrammatic view, in longitudinal section, of one of the evaporator tubes of the installation.

  The installation according to the invention, illustrated in Figures 1 to 3, is in the form of a thermal machine of generally cylindrical horizontal shape. The cylindrical casing 1 of the machine may be made of insulating material; its inner face is advantageously lined with refractory bricks 1 '.

  This thermal machine comprises an inlet 2 for the liquid or semiliquid effluent to be treated, which ends in a chamber 3 equipped with a heat exchanger system 4 ensuring the preheating of the effluent. After being heated, the effluent to be treated is directed by a pump system (s) 5 to means 6 arranged in the upper part, adapted to ensure the evaporation of part or all of the water it contains.

  The water vapor generated by the evaporator means 6 is recovered in the chamber 7 and conveyed via the pipe 8 to the heat exchanger system 4 to provide the aforementioned preheating operation. At this heat exchanger 4, the water vapor is converted into hot water; this hot water is discharged through the outlet pipe 10, for example to be returned to the industrial process. In FIG. 1, it can be seen that the pipe 10 is equipped with a pressure regulator 11.

  Depending on the use that will be made, this recovered water can be remineralized by any technical process known to those skilled in the art.

  The solid or pasty waste (dehydrated organic matter) resulting from the evaporation operation in the evaporator means 6 is recovered in the chamber 7 by conveying means 12 adapted to ensure either their external evacuation, for example for their recycling in the industrial process (especially for cellulosic fibers), or their introduction into an incinerator furnace 14 disposed just below the evaporator means 6. These conveying means 12 may consist of a worm conveyor driven by a suitable motorization.

  The furnace 14 thus generates the energy necessary for evaporation of the water in the evaporator means 6.

  This incinerator furnace 14 burns solid or pasty waste to transform them into ash, smoke and combustion gases. Ashes are removed by exhaust ducts connected to a suction unit (not shown). The flue gases and flue gases are recovered in an energy chamber 16, after being treated in a thermal oxidation chamber 17. They are then conveyed within the evaporator means 6 to exit through the pipe 18 before final condensation in a chamber of energy recovery 19, then purified with filters before atmospheric discharge via the conduit 20.

  The heat exchanger system 4 consists of a plurality of small section tubes.

  The evaporator means 6 consist of a plurality of horizontal tubes 22 connected in parallel in the form of rings (FIG. 3) to define types of central ducts 22 '. Each tube 22 has a length of up to several meters (for example 5 meters) and has a diameter for example of the order of 15 centimeters. As can be seen in FIG. 3, in the illustrated embodiment, the installation comprises 11 rings each formed of six evaporator tubes 22.

  2865202 One of these evaporator tubes 22 is shown in isolation and schematically in FIG. 4.

  As detailed in this FIG. 4, the evaporator tubes 22 comprise an upstream opening 23 through which between the preheated effluent coming from the pump system (s) 5, and a downstream opening 24 through which the solid or pasty waste resulting from evaporation of water.

  The inside of the tube is equipped with means for driving the effluent to direct it from the upstream opening 23 to the downstream opening 24, consisting of a longitudinal floating helical blade 25. This helical blade 25 is devoid of central core which facilitates the evaporation of water and the transfer of water vapor generated to the downstream opening 24. It is rotated by a motor actuating a pinion 26; it is mounted on bearings 27 and 28 at its two ends and is held by a plurality of tensioned cables 29, to allow its peripheral edge to properly scrape the entire inner surface of the tube.

  The blade 25 thus allows the conveying of the effluent and the scraping scale deposits. The pinion 26 is arranged at the end of a drive shaft 30 also mounted on bearings 31. Between the shaft 30 and the scraper blade 25, there is the presence of a spring system 32 tension and expansion compensation (this spring 32 is carried by the shaft 30 in association with a sliding bearing 33).

  Several pinions 26 may be driven by gears fixed on an axis controlled in rotation by the same motor.

  For example, as shown in FIG. 3, the helical blades of each stage of evaporator rings can be controlled by a single motor 34.

  The distribution of the preheated effluent from the pump system (s) 5 in the various tubes 22 is made from a pipe 35 feeding a nanny by means of different feed tubes located on the upstream portion of the evaporator tubes 22.

  The water vapor formed in the evaporator tubes 22 is evacuated through the downstream openings 24; it is recovered in the vapor / solid separation chamber 7, then through the aforementioned pipe 8. As explained above, this pipe 8 transports the steam to the heat exchanger system 4; a mechanical compressor 36 can be interposed on this pipe 8 to transfer the condensation energy to the heat exchanger 4.

  The solid or pasty waste resulting from the evaporation of the effluent falls by simple gravity from the chamber 7 on the screw conveyor 12.

  The drive of the screw in one direction ensures the external evacuation of this waste, and its drive in the other direction transports the waste in question in the incinerator furnace 14.

  This incinerator furnace 14 is advantageously of pyrofluid type operating by means of gas burners or fuel oil. It has two beds, each equipped with a 40-41 burner and a 42-43 mixing and mixing system for waste and ashes.

  The brewer / mixer systems 42-43 each consist of a rotary shaft mixer with a vertical axis, associated with a rotary valve-shaped ashing system 44. As previously indicated, these rotary valves 44 are connected to a duct. 15 connected to a suction unit allowing operation in the manner of a venturi system: the ashes are sucked by the system, which allows to store them directly at the same time as supplying the furnace with oxygen.

  It will also be noted the presence of air injection nozzles 45 arranged at the bladed mixers 42-43, also ensuring the supply of fresh air in the oven, but above all allowing the fluidization of the oven beds. The nozzles 45 are fed by ducts 46.

  A first mixer / stirrer 42 is arranged under the first burner 40, near the outlet of the evaporator means 6 and the waste conveyor 12. A complementary arrival 47 of solid waste, for example in the form of a screw conveyor, is provided in FIG. level of this first burner group 40/42 mixer. This arrival 47 allows for example the introduction of solid materials like sawdust, bark or shredded wood.

  A second mixer / stirrer 43 is provided under the second burner 41; a complementary arrival 48 of solid waste, for example in the form of a screw conveyor, is provided at this second burner unit 41 / mixer 43; this arrival 48 allows for example the introduction of solids like refusal of recycling (plastics, paper, cardboard ...).

  The combustion gas / flue gas recovery chamber 16 and the oxidation chamber 17 are arranged between the heat exchanger 4, on the one hand, and the evaporator means 6 and the furnace 14, on the other hand.

  The gases and fumes coming from the combustion of the solid waste in the furnace 14 are transferred by a suitable pipe, made of refractory materials such as 1 ', into the oxidation chamber 17 where they are treated for a time longer than the second, to a very high temperature (of the order of 1100 C), this by means of a burner 49. The transfer line of gases and fumes from the furnace 14 to the oxidation chamber 17 has not been represented in Figure 1, its entry into the chamber 17 is marked 50 in Figure 2.

  After introduction and treatment in the chamber 17, the gases and fumes pass into the energy recovery chamber 16 through an orifice 51.

  The fly ash is removed from the chamber 16 by a conduit 52 associated with a rotary valve 53.

  The combustion gases leave the chamber 16 via a duct 54 and they are distributed in a circular duct 55 (FIG. 1) placed between the chamber 16 and the group formed by the evaporator means 6 and the oven 14. This circular duct 55 is thermally insulated, for example by ceramic fiber materials and special fabrics. It makes it possible to evenly distribute the combustion gases in the central ducts 22 'of the evaporator means 6 via suitable ducts.

  In the energy recovery chamber 19, there is the presence of a heat exchanger 56 adapted to heat air for supplying the burners 40, 41 and 49; the hot air in question is conveyed to the burners by appropriate pipes. The advantage of this reheating of the air is to reduce the temperature differences of the outside air entering the oven.

  The fan 57 illustrated at the level of the energy recovery chamber 19 is intended to condense the fumes and gases at the output of the process and to supply the burners with hot air.

  The installation described in Figures 1 to 4 is particularly suitable for the treatment of effluents from the pulp and paper industry or for the treatment of water and urban sludge.

  As mentioned above, it could also be adapted to ensure the production of drinking water by desalination of seawater or by distillation of river water.

8 2865202

Claims (15)

- CLAIMS -   1.- Installation for treating liquid or semi-liquid effluents and possibly solid waste, characterized in that it comprises: at least one inlet (2) for the effluent to be treated, - means (6) adapted to to evaporate at least part of the water contained in said effluent, to ensure its transformation into water vapor, on the one hand, and into solid or pasty waste, on the other hand, means ( 8, 10) for evacuating the water vapor or the water generated by this water vapor, - oven-shaped means (14) for incinerating said solid or pasty waste in order to reduce it to ashes, which incinerator furnace (14) is disposed under said evaporator means (6) so as to use the combustion energy of said solid or pasty waste to provide the aforesaid evaporation, and - ash removal means (15, 44) generated by said incineration.   2.- Installation according to claim 1, characterized in that it comprises heating means (4) of the liquid effluent before entering the evaporator means (6).   3.- Installation according to claim 2, characterized in that the means for heating the liquid effluent before entering the evaporator means (6) consist of a heat exchanger (4) fed by the steam generated by said evaporator means (6), the installation further comprising an outlet (10) for the water coming from the cooling of the steam by said heat exchanger (4).   4.- Installation according to any one of claims 2 or 3, characterized in that it comprises means (5, 35) ensuring the transfer of the heated effluent to the evaporation means (6).   5.- Installation according to claim 4, characterized in that said transfer means consist of a pump system (s) (5) and pipe (s) (35).   6.- Installation according to any one of claims 1 to 5, characterized in that it comprises an incinerator furnace (14) provided with at least one burner (40, 41) and at least one brewing system (42). , 43) solid waste and ashes.   7.- Installation according to claim 6, characterized in that the solid waste brewing system and ash consists of a rotary blade type mixer vertical axis (42, 43), associated with a system of evacuation of ash shaped rotary valve (44).   8.- Installation according to any one of claims 1 to 7, characterized in that it comprises at least one inlet (47, 48) for solid waste directly at the incineration furnace (14).   9.- Installation according to any one of claims 1 to 8, characterized in that it comprises incinerator means (14) associated with a chamber (17) of thermal oxidation of fumes generated by the combustion of solids.   10.- Installation according to claim 9, characterized in that it comprises means (52, 53) for the evacuation of fly ash from the oxidation chamber (17).   11.- Installation according to any one of claims 9 or 10, characterized in that it comprises means (16, 54, 55) which allow the sending of hot air from the oxidation chamber (17 ) towards the evaporator means (6).   12.- Installation according to any one of claims 1 to 11, characterized in that it comprises a system (12) for recovery of solid waste or semisolides from the evaporator means (6), adapted to allow the transfer of said waste is towards the incineration furnace (14), or outwards.   13.- Installation according to any one of claims 1 to 12, characterized in that it comprises an incineration furnace (14) comprising a first mixer (42) arranged below a first burner (40), to near the outlet of the evaporator means (6), an inlet (47) of solid waste being provided at said first mixer (42), and a second mixer (43) arranged beneath a second burner (41), a complementary arrival (48) of solid waste being provided at said second mixer (43).   14.- Installation according to any one of claims 1 to 13, characterized in that it comprises evaporator means (6) consisting of a plurality of horizontal or substantially horizontal tubes (22) provided with an upstream opening (23). ) and a downstream opening (24), which tubes (22) are each connected to the effluent supply means (5, 35) at their upstream opening (23), and which tubes (22) comprise means (25) driving said effluent towards their downstream opening (24).   15.- Installation according to claim 14, characterized in that the effluent driving means arranged in the evaporation tubes (22) consist of a longitudinal floating helical blade (25) mounted on bearings (27, 28). and held by a plurality of longitudinal cables (29).