CH622090A5 - Plant and method for continuous processing, using infrared rays, of materials which contain volatile components - Google Patents

Abstract

The plant comprises a tank (12) which delimits a combustion chamber, at one end of which there is an aperture for intake of the material, and at the other end an aperture for discharge of the material processed, and a conveyor belt for supplying thereto the materials to be processed. On the tank there are mounted (infrared ray) lamps for heating these materials, a device (11) for loading these materials on the conveyor belt, and to the tank there is attached a hopper (130a) for removing the processed materials from the combustion chamber. Additionally, it comprises ducts (20) which are supplied by a fan (80), in order to force air between the combustion chamber, around the infrared ray lamps, a drawing duct (16) for causing a counter-current flow, in the combustion chamber, of the mixture consisting of air and combustion gas, relative to the motion of the conveyor, and a temperature-sensitive element (200) for varying the temperature of the said mixture. In addition to the high yield which can be obtained with a limited capital investment, the plant permits elimination of all foreign bodies and substances from the surfaces of activated carbon particles, such as to obtain initial activation or regeneration of granules or powder of the said carbon. The plant is used for sewage sludge incineration. <IMAGE>

Description

The present invention relates to a plant and a process for continuously treating materials having volatile components with infrared rays. In particular, the invention is used in a plant for the incineration of sewage sludge from waste water treatment plants. The invention also applies to the initial activation and regeneration of granules or activated carbon powder, which can be used for adsorption purposes in the treatment of waste water and the like.

Sewage sludge is that part of semi-solid sludge that settles after certain industrial and municipal sewage treatment processes. In certain cases, today, this waste is used as fertilizer or eliminated by burying it in holes or excavations in the ground.

According to other solutions, it is expected to eliminate such waste by burning it in incinerators.

However, the latter are generally large low-yield plants that require large capital investments.

A typical load of such sewage sludge can comprise 20% of solid material and the remaining 80% of liquid. In 20% solid material, 75% can be volatile and therefore combustible in the present apparatus. Therefore, of the total original quantity of sewage sludge, 80% of liquids can be eliminated by vaporization while combustion eliminates 75% of the remaining 20% of solid material so that, of the initial total weight of sludge, only 15% it will remain s in the form of ash for which a further method of elimination must be provided.

In the treatment of sewage, activated carbon is used as an adsorbent both in granular and in pulverulent form. This coal is a porous material having a large number of cavities, to which the substances which are to be removed and removed from the water or other fluid under treatment are attached. These carbon particles, after being saturated with the various contaminants, must be eliminated or reactivated by eliminating said contaminants attached to said plurality 15 of carbon surfaces and thus restoring the cavities of the particles. The coal will then be ready to be reused. Furthermore, during the production of activated carbon, certain binding agents are used which also must be removed before the particles are ready to be used in the 20 various treatment and purification processes mentioned above.

To activate and reactivate carbon particles, conventional ovens have been used to date, however expensive they are, have low performance and are difficult to control so that they maintain the required state for 25 optimal coal treatment, this which means that the foreign material is removed from the cavities of the carbon particles while leaving the latter intact so that they can be reused. If said combustion and oxidation control is lacking, the carbon-30 carbon particles will also be lost.

The object of the present invention is to provide a plant for the continuous treatment with infrared rays of materials having volatile components, in particular for the incineration of sewage sludge, having a high efficiency and obtainable with limited capital investments. • A particular object of the invention is also to provide a system that allows the elimination of all foreign bodies and substances from the surfaces of carbon particles, both externally and internally, making them available 40 for adsorption, of a maximum amount of surface.

The plant according to the present invention is characterized by what it comprises:

- a box that delimits an elongated combustion chamber having at its end an entrance opening and

<5 at the other end a discharge opening;

- a conveyor belt mounted on rollers which make it move inside said combustion chamber and having a top part of belt suitable for advancing the materials to be treated within and along said combustion chamber from said opening opening to said discharge opening and furthermore provided with a part of return belt arranged inferiorly with respect to said part of upper belt;

- infrared heating means mounted on said body and capable of radiating heat on said materials which are located

55 compartment on said conveyor belt while the latter advances said materials along said combustion chamber, from said materials releasing combustion gases due to the heating due to said infrared rays;

- loading means connected with said bin to the entrance end of said combustion chamber to receive the materials from a supply point and suitable for unloading said materials on said conveyor belt which is located in said chamber;

means for removing the treated materials from said 65 combustion chamber at the discharge end of the same chamber;

means connected to said body to forcefully push ambient air into said body;

- means for creating a draft at the

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inlet end of the combustion chamber in order to cause a backflow of the mixture composed of air and combustion gases, said mixture reflecting parallel and above said materials, from the discharge zone in the direction of said material inlet opening; s

- and temperature detecting means arranged inside said box above said conveyor belt and connected to control means for varying the temperature of said mixture in counter-current, controlling the emission intensity of the ray heating means. I

Furthermore, the system commissioning procedure is characterized by what comprises the following operations: supporting said materials on a mobile belt within a box, which defines a combustion chamber;

striking with infrared radiation said materials while moving on said belt along said combustion chamber;

causing combustion gases to flow back in counter-current along said combustion chamber in a direction opposite to the direction of movement of said belt while said materials are treated thereon and within said chamber. . 20

The process for the initial activation and regeneration of activated carbon particles in which the plant has means for controlling the atmosphere in the combustion chamber, characterized in that it comprises the operations of:

- supporting said carbon particles on a continuous conveyor belt inside said box which delimits the combustion chamber;

- hitting said carbon particles with infrared rays while the latter move along said combustion chamber by the action of said belt to burn said foreign substances 30 out of said particles;

- controlling the atmosphere in said combustion chamber around said carbon particles to effect the combustion of essentially all foreign substances outside said carbon particles and at the same time ensuring that the 35 carbon particles themselves do not burn.

For the treatment of sewage sludge, the latter are fed in the form of very thick sludge within a complex which includes a bending tank and a feeding apparatus, in which the sludge 40 moves by means of an auger and under the intense heat action obtained with infrared rays which results in a "bursting" or fragmentation of the material, with consequent removal of moisture contained in it.

The material is then passed through a grinding mill 45, and then over a vibrating conveyor in order to deposit the earth particles contained in the fragmented material and before it is conveyed into the combustion chamber. In the latter, the waste particles are deposited on a conveyor belt, along which they are subjected to a subsequent intense and concentrated heat action, which comes from infrared heating lamps arranged above said combustion chamber, the latter being maintained under a slight vacuum. In it, the flux of the combustion gases is controlled so as to generate a reflux of the gases in the opposite direction to the movement of the belt, and this is to preliminary heat the material and remove part of the humidity and at the same time to increase the heat in the chamber. combustion in addition to what already comes from infrared lamps.

The plant according to the invention, together with its aims and advantages, will be explained more fully in the following description of preferred forms of the invention to be considered with reference to the attached drawings wherein: 65

Fig. 1 is a side elevation view, partially schematic and cross-sectioned, of a preferred form of an incineration plant according to the present invention suitable for being used in the treatment of sewage sludge and similar waste;

Fig. 1-A is a fragmentary and enlarged elevation view that represents the feeding group of the plant which includes the feeding conveyor, the grinding mill and the relative appliances connected to the entry end of the combustion chamber to feed the material to be treated within the system;

Fig. 2 is a fragmented and enlarged sectional elevation view of a part of the combustion chamber and of the partially split chamber to show the infrared heating units, the conveyor belt, the air supply systems and the relative structural components ; Fig. 3 is my enlarged sectional view taken along the line

3-3 of fig. 1 illustrating one of the infrared heating units and a pair of the support rollers of the conveyor belt;

Fig. 4 is a further enlarged section taken along the line

4-4 of fig. 3 which represents a fragment of the conveyor belt and one of the belt support rollers;

Fig. 5 is an enlarged and fragmentary section view illustrating a part of a mud mixing bar;

Fig. 6 is an enlarged and raised section taken along the line 6-6 of fig. 5 which illustrates the assembly structure of the mixing bar and one of the teeth of said bar;

Fig. 7 is an elevation view from below taken along line 7-7 of fig. 5 illustrating a part of a stir bar with one of the teeth;

Fig. 8 is a sectional view taken along line 8-8 of fig. 1 which represents the feeding auger and an infrared heating unit, mounted above the auger for the initial fragmentation and removal of moisture from the sewage sludge and similar waste materials;

Fig. 9 is a fragmentary top view showing the cooling and combustion air supply system, which serves to supply cooling air to the infrared and air heating units, which favors combustion to the combustion chamber;

Fig. 10 is a broken and broken side view of a modified embodiment of the plant according to the present invention suitable for activating and / or reactivating activated carbon particles;

Fig. 11 is an enlarged fragmentary sectional view taken along the line 11-11 of fig. 12, which illustrates a modified form of the combustion chamber, of the air flow system for supplying cooling air independently of the combustion chamber, for cooling the infrared heating lamps in the system of fig. 10;

Fig. 12 is a fragmentary top view of the combustion chamber, in which the air flow system is modified so as to adapt to the shape of the apparatus illustrated in fig. 10.

With reference to the drawings, a waste incinerator 10 for the treatment of sewage sludge and the like comprises a feeding apparatus 11, an elongated tube-shaped housing or container 12, which defines a combustion chamber 12a, a heating unit Infrared rays 13, an ash removal unit 14, an apparatus 15 for washing gases, a flue gas exhaust 16 and a system 20 for supplying air for cooling and combustion. The waste to be treated is fed through the feeding apparatus 11, which continuously supplies the combustion chamber.

Within the combustion chamber (12a), the waste continuously moves on a conveyor belt arranged under infrared lamps, which radiate intense heat, which, in combination with the heat generated by the combustion of the waste, essentially reduces com-

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pity, burning the waste within the combustion chamber. At the discharge end of the conveyor belt, the ash remains are deposited within the appliance 14, while the gaseous products of combustion flow back to the exhaust 16 passing along the material to be burned, which is located on the belt inside the combustion chamber. The combustion air, which enters the system around the infrared heating units, is preheated by the lamps. In the washing bubbler device 15, the exhaust gases coming from the combustion chamber are cooled and ventilated eliminating the solid particles that they carry. The combustion chamber is operated under a slight vacuum to prevent harmful fumes from escaping from the chamber during the combustion process.

The sludge feeding apparatus 11 comprises a piezometric hopper-shaped tank 21, into which the sludge coming from a feeding source, not shown, enters. The piezometric tank 21 is mounted on a feed pump 22, which discharges into an conveyor 23 enclosed in an elongated casing 24, in which casing an auger 25 is mounted rotatably between bearings 30, flanged mounted and fixed at the ends opposite of the same envelope. One end of a shaft 32, which supports the feeding auger extends from the bearing 31 and supports a pulley 33, driven by a belt 34 by a motor 35.

A particularly unique and exceptional feature of the feeding device 11 consists in the fragmentation of the sludge, obtained by the intense application of heat by a pair of infrared heating units 40 mounted on the casing 24 which contains the auger 25 supply, and precisely arranged towards the discharge end of the latter. With particular reference to fig. 8, the part of the feeding auger on which the heating units 40 are mounted is insulated by a layer of cast refractory material 41, which extends along the sides and the bottom of the casing 24 for a distance slightly greater than the lengths combined of the two heating units 40. The refractory layer is covered by an external shell 42. As is particularly evident from fig. 8, the insulated part of the casing 24, which contains the auger, is in a U-shaped section and is open at the top along the entire length of the heating units. The top of the insulated part is covered by a quartz panel 43 which forms a protective or lens window between the feeding auger compartment and the heating units. The quartz panel rests on the upper edges of the auger casing, and is fixed by flanges 44 connected to the casing 45, in which the infrared lamps 50 are suspended. The latter are convenient type infrared lamps, capable of quickly bringing to approx. 1370 ° C (2500 ° F) the sludge temperature while it moves due to the action of the auger placed under said heating units. The quartz panel 43 effectively shields the lamps by sheltering them from the dirt and humidity of the mud while, at the same time, allowing the radiation of the heating units to hit the muds at full intensity causing their fragmentation with consequent removal of moisture from them.

The ray heating lamps 50 are connected by means of conductors 51, which lead to a control panel 52 to supply electricity to the same lamps and control their intensity.

Downstream of the infrared heating units 40, the casing 24 of the feeding auger 25 is connected with a vertical conduit 53, connected at its upper end with the conduit 16 for refluxing the exhaust gases to allow the expulsion of the vapors generated in the casing 24 during the fragmentation phase of the mud by the action of the infrared lamps 50. As shown in fig. 1-A, the auger conveyor 23 unloads downstream into a hammer-type mill 54, which reduces the size of the mud particles to a diameter which does not exceed from ca. 1.25 cm to 1.90 cm (% per inch). The mill can be any known hammer mill, suitable for reducing the particles to the desired dimensions. The mill is connected with an elastic joint 55, fixed to the upper end of an inclined vibrating conveyor 56, which discharges into the inlet opening of the box 12 of the combustion chamber 12a and precisely onto the conveyor belt 90 arranged inside said box. The conveyor 56 will be of any known type suitable for vibration, e.g. a conveyor with a feeding table activated by means of solenoids. A conveyor feeding table unloads along a weir or measuring device 56a, mounted on the discharge end of said table, to distribute and adjust the height of the layer of mud particles to be prepared on the supply table thus allowing a regular and uniform feeding to our conveyor 90 located in the combustion chamber 12a. A flexible conduit 57 is connected between the discharge end of the vibrating conveyor and the top of the box 12.

The combustion chamber 12a, delimited by the elongated box 12 shown in fig. 3, is generally of rectangular section. The body has a bottom panel 60 connected with spaced lateral vertical panels 61, both consisting of suitable metal sheets. Within the bottom and side panels, the combustion chamber is internally lined with a double layer of refractory material, which comprises an external insulating layer 62 and an internal layer 63 of printable, low corrosion refractory material. With the external refractory insulation layer 62 it is desired to satisfy most of the caloric insulation requirements, which layer 62 is made of suitable refractory material which however is not able to withstand the severe stresses due to the drastic changes in temperature that result from the direct exposure to heat within the combustion chamber 12a. The internal insulation layer 63, on the other hand, is formed of suitable refractory material capable of resisting these last drastic temperature variations. The absolute insulation qualities of the inner layer are essentially lower than those required of the materials to be used for the outer insulation layer. The top of the box 12, both upstream and downstream of the infrared heating units 13, is constituted in the same general way in which the walls and the bottom represented in fig. 3. The opposite side walls of the casings of the heating units 70 have air inlet openings 71 and 72 for cooling the lamps and the combustion air. The end seals of the lamps require particular cooling and the heat absorbed by the air is used for preheating for combustion purposes while said hot air flows downstream into the combustion chamber.

A plurality of transversal infrared heating lamps 73 are spaced along the entire length of the combustion chamber within the casings 70, supported by the upper panels of the same casings 70.

The infrared 73 lamps are designed and drawn appropriately, so as to provide heat up to a temperature ranging from approx. 650 ° C to 930 ° C (1200 ° F to 1700 ° F) so as to complete the heat generated by the combustion of the sludge inside the chamber. Electricity is supplied to the infrared lamps via a conductor 74 from the control panel 52. The cooling air for the ray heating lamps 73 enters through the ducts 75 and 76, connected with the pump or fan 80. The horizontal portions of the cooling ducts 75 and 76, which s

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they extend longitudinally to the infrared heating units 13, are fixed along the opposite side walls of the casings 70 of the heating units and are equipped with openings 81 and 82, which coincide with the openings 71 and 72 respectively of the same casings so that the air supplied by the pump 80 is distributed laterally inwards through each casing 70 in order to cool the lamps inside them.

Another pair of combustion air inlet ducts 77 and 78 is connected to the fan 80, as shown in fig. 9, to supply additional or secondary air to the combustion chamber. The ducts 77 and 78, which comprise the valves respectively IIb and 78b are arranged externally, at a certain distance and under the ducts 75 and 76 and are connected at spaced intervals with the combustion chamber by short branches 77a and 78a respectively, which branch off from the ducts 77 and 78. The branches 78a communicate with the openings 78b made in the side walls and the internal ceramic lining of the combustion chamber body, while similarly the branches 77a communicate with openings 77b made in the side wall and in the internal ceramic coating of the combustion chamber box. The additional combustion air can then be pumped through the ducts 77 and 78 into the combustion chamber which is located under the infrared lamps. If desired, this additional combustion air can be supplied by another fan and controlled separately so that, if necessary, said air can be used to facilitate temperature control for the purpose of tempering it.

The sludge moves along the combustion chamber 12a on the conveyor belt 90, supported by a plurality of spaced bearing units 91 which move the sludge from the exhaust 57 from the feeding apparatus 11 to the gas washing and elimination device 15 of the ashes 14, at the other end of the combustion chamber. The conveyor section consists of a suitable articulated chain system capable of operating continuously while being exposed to extremely high temperatures ranging from 815 ° C (1500 ° F) and up. In the particular conveyor system shown, a roller unit is arranged at the opposite ends of the combustion chamber and three pairs of rollers, upper and lower, are arranged along the combustion chamber, between the end rollers, and are used to support the continuous conveyor belt. The belt moves over both the upper and lower rollers and around the end rollers. The roller unit at the drive end of the belt is connected to a gear 92 energized via a belt 93 by a motor 94. The gearbox includes means not shown for adjusting the belt tension.

With particular reference to fig. 3, each of the roller units 91 is supported on side shelves 95, fixed to the side panels 61, which form the opposite walls of the compartment 12 of the combustion chamber. Bearings 100 are bolted to the brackets 95 to support a shaft 101 supporting the roller 91. Each of said shafts has, spaced along its length, four radial protrusions 102, which support a cylindrical roller 103. The opposite ends of the rollers are equipped with stuffing box 104 formed by an annular flange 105 fixed to the side panel of the body and screwed inside a cap 110. An asbestos rope 111 is contained in a ring within said cap against the outer end of the flange and around the roller to seal tightly and prevent leaks of heat from inside the combustion chamber along the external surface of each roller. The opposite ends of the rollers are open to the atmosphere, so that air can circulate along the entire length of the rollers along the annular space defined within the roller around the shaft 101. There are observation openings 112 having removable covers 113, to allow visual inspection inside the combustion chamber, and which are obtained along the side panels of the box.

5 Spaced along the combustion chamber, on the upper part of the conveyor belt 90, which supports the material, there are barrel mixing units 120, which turn and turn and generally agitate and mix the sludge to be incinerated that are on the conveyor belt for I'd better expose them to the combustion process. Each mixing unit comprises a transverse bar 121 mounted at each end on a shelf 122 by means of bolts 123 (figs. 5,6). The shelves are mounted through the two layers of refractory inner lining material, with cleats 126, which protrude through the side wall 61 of the combustion chamber box. A plurality of plow teeth 124 are spaced over the entire length of each bar, so that their tips are located at a small distance from the upper surface of the conveyor belt 90. All the teeth 124 20 have a concave mixing surface 125, which allows them to "plow" the sludge which is on the upper surface of the conveyor belt in such a way that said sludge is thoroughly stirred as it moves on said belt inside the combustion chamber. Several mesco-25 laminating units are arranged along the entire length of the belt with its teeth positioned in such a way that all the mud is stirred as it is placed on the belt. The teeth are spaced and positioned on the various stirring bars in a variable way, so as to ensure optimal agitation and mixing of the mud 30 when it has passed under all the bars.

The discharge end of the combustion chamber 12a is connected with a casing 130, fixed to its upper end and by means of a flanged joint 131 to an exhaust chimney 131a having a damping valve 131b. A removable inspection door 35 is fixed in the side panel of the casing 130 as shown in fig. 1. A lower hopper part 130a of the box communicates directly with the feeding end of a screw conveyor 133 driven by a belt 134 by a motor 135. The screw conveyor-40 discharges downward into an element with cups 140 driven by a motor 140a. The elevator discharge is connected via a conduit 141 with a hopper storage tank 142, which can be discharged through a bottom door 143 to remove the

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The exhaust 16, for the reflux of the exhaust gases, is connected at one end with the inlet end of the container 12 through a valve 16a. The other opening of the lócol-50 drain connected with an elbow duct 150 with the scrubbing bubbler 154. The elbow 150 opens within a spraying member 151 having a plurality of spraying jets 152 vertically spaced and fed through a conduit 153, which feeds water from a source of supply, not represented. The sprinkler member discharges into a standardized convenient type scrubber 154, fed with water through a conduit 155. The gas from the scrubber 154 is discharged into the atmosphere through a chimney 161 by the action of a fan. exhaust 160 driven by a motor 162.

The box 12 of the combustion chamber is mounted on a pair of spaced and parallel profiles 180 C, supported by columns 181. At a lower level, the engine 94 and the relative drive mechanism, at the input end of the 65 body of the combustion chamber, are mounted on C-shaped pieces 182 supported by a spaced pair of similar columns 183. The entrance end of the combustion chamber has a hopper part 190, which is equipped with a door

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for cleaning 191 which allows to remove ash and various waste collected at the entrance end of the chamber.

The control panel 52 is connected with the infrared heating units 40, provided in the supply system 11, with the infrared heating units 13 of the combustion chamber 12a and with the temperature sensitive elements, which are used to determine the temperature of the exhaust gases and to supply air and the like to allow adequate control of the incineration process. A temperature sensitive element 200 is mounted within the case 130 to read the temperature in the combustion chamber at the discharge end of the conveyor belt. The element 200 is connected by an insulated conductive wire 201 to the control panel. A recorder 202 with multiple writing tips is connected via a conducting wire 203 to a temperature detector 204 provided in the reflux duct 16, which comes from the combustion chamber. Another temperature detector 204a, arranged in the upper part of the casing 130, is connected by a conducting wire 205 to the recorder. A further temperature detector 210, at the discharge end of the washing bubbler 154, is connected by a conducting wire 211 to the recorder.

A manually controlled valve 130b, to allow communication between the atmosphere and the base end 130a of the casing 130, is provided in the lower discharge part of the casing 130 above the auger conveyor 133. A cap-type thermal welding piece 130c it is fixed in the discharge part of the casing 130 and is adapted to receive a temperature detector, if desired. The functions of the recorder 202, which detects and registers the critical operating temperature, as well as the functions of the control panel 52 can be completely automated, completely manual or even in different degrees between complete automation and manual operation as appropriate, first object being to control the operation of the incinerator so as to achieve a maximum efficiency. While the main function of the panel 52, in the illustrated arrangement, consists in maintaining a certain desired temperature of the infrared heating units 13 and 40, said panel can also perform other functions if required and desired, depending on the level of automation that you want to achieve in the system. For example, through the panel 52 it will be possible to control the backflow control valve 16a, the air tempering valves 77b and 78b, suitable for introducing air to contribute to the control of combustion, and other controllable functions of the type e.g. the supply of cooling air and combustion support from the system 20, all to completely adjust as best you want and require all the variables existing in the system in order to obtain optimal operation.

When the incinerator is in operation, the material to be treated, which can be sewage sludge from a municipal or industrial sewage treatment plant, is fed continuously and in quantities appropriate to the capacity of the incinerator. , within the feeding assembly 11, through the piezometric tank 21. The sludge is in the form of a slime-type sludge that contains solid material and liquids in different percentages according to the types of process of the purification plants from which they come. The solid material can form a large part of the total mud volume. The latter is discharged from the pump 22 into the auger conveyor 23, where the auger 25 pushes it along the conveyor. As it moves along the casing of the conveyor due to the action of the auger, the mud passes along the part of the conveyor heated by infrared lamps 50. The intense heat of the lamps, which can be in the order of 1370 ° C (2500 ° F)

it is directed, through the quartz panels 43, on the mud that is moving due to the action of the auger. The intense and violent change to which the mud is subjected while moving from the unheated inlet end of the feeding conveyor to the extremely high temperature zone, obtained as a result of the 50-ray lamps, causes instant vaporization of an essential part of the humidity found in the sludge and the effect of said vaporization is of an explosive type, causing the sludge to break down into particles which are incinerated much more easily in the combustion chamber. The fundamental purpose of the heat coming from the infrared lamps along the auger conveyor 23 is not the removal of humidity but rather the fragmentation of the mud, which when it enters the conveyor of 15 usually forms an agglomeration due to hair, hair and generally fibrous particles that bind it together. The area along the auger conveyor 23, in which heat is radiated, reaches temperatures of the order of 980 ° C - 1370 ° C (1800 ° F - 2500 ° F), which are necessary to produce the vapor. 20 instant explosive erection which serves to separate or break the particles of fibrous material, hair or hair, thus breaking the bonds that hold large pieces of mud together. Furthermore, some combustion of minor importance will certainly take place, and there will certainly also be some liquefaction or fusion of the hair and hair and other fibrous particles. The fragmented sludge is discharged by means of the feeding auger 25 into the hammer mill 54, which grinds it, reducing it to uniform dimensions and deposits it on the vibrating unit 56. The latter subjects the mud particles to vibrate long-30 g. the flat surface, feeding them under the cross member or barrier 56a, which levels and distributes them, bringing them to a uniform layer. The sludge particles are then discharged from the conduit 57 into the feed end of the conveyor belt 90 into the combustion chamber 12a. The humidity 35 and the other gaseous by-products, obtained by the action of the fragmentation heat at the discharge end of the feed conveyor, are discharged from the conveyor body by means of the vertical flow conduit 53, through which they flow to the ebb 16.

The conveyor belt 90 is driven by the motor 94 at a speed calculated in such a way as to allow complete combustion of the sludge, combustion which must be completed between the point of deposit of the sludge on the belt and the discharge end above the appliance 14 of removal of the ash, which is 45 at the base of the chimney box 130. Obviously there are a number of variables that determine the speed at which the conveyor belt must be operated. For example, the physical nature of the sludge, which depends on the percentage of humidity and combustible solids, determines the time required to completely expel the humidity from the mud and completely incinerate the combustible part of the solids. The actual sludge incineration process, while it moves along the conveyor belt, is obtained by the combined effect of the heat supplied by the infrared lamps 73 in the 55 heating units 13 and the heat generated by the combustion of the volatile substances contained in the mud.

Obviously, at the beginning of the operation of the incinerator, no combustion products will be available and therefore not even by-products that provide recycling heat. Therefore 60, the first heat applied to the sludge within the combustion chamber will be that supplied by the ray heating lamps 73, which are located towards the entrance end of the chamber. The sludge is heated along the combustion chamber and brought to a temperature from 650 ° C to 925 ° C (1200 ° F to 65 1700 ° F), with the initial removal of the humidity, then following the incineration of the volatile parts of the mud. The gaseous vapors, which come out of the liquid material found in the mud and the combustion gases which result from the burning of the particles

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solid, they flow back in the opposite direction along the combustion chamber, and are discharged through the tubular system 16, then reaching the gas washing device or bubbler 15. Along the combustion chamber, in the opposite flow direction, a forced air stream is formed by the combined action of the fresh air which promotes combustion and comes from the system 20 and the reflux gases, drawn along the exhaust 16, from the jets of water 152 and the condensation that takes place in the washing device 15.

The combustion and cooling air is introduced into the combustion chamber 12a by a fan 80, which discharges through the ducts 75, 76,77 and 78 into each of the heating units 13 and into the sides of the combustion chamber as shown in fig. 3. Air flows laterally inwards along the casings 70 of the heating units 13 as indicated by the arrows in fig. 3 and fig. 9, which give the direction of flow. Within the casings 70 of the heating units 13, the air from the ducts 75 and 76 serves to cool the infrared lamps 73 and the end seals of the said lamps, and at the same time to preheat the air. The heated air flows downwards into the combustion chamber mixing with the air from the ducts 77 and 78. The heated air promotes combustion thanks to its caloric value as well as thanks to its oxygen content. In addition, the reflux combustion gases help to increase the heat supplied to support the combustion of the mud. These heat sources, combined together, reduce the required amount of heat required by infrared lamps.

For the same type of sludge and during the initial phase of the combustion process, the conveyor belt must be operated at a very low speed compared to the speed it can then have when the incinerator is operating at full efficiency. Obviously, it takes longer to initially heat the whole system, start removing the moisture and start the combustion which reaches a complete combustion when the system is already in full operation.

When combustion is fully achieved, the combustion process is kept under control to maintain an approximate temperature of 920 ° C (1700 ° F) at the discharge end of the conveyor belt, and as required by the temperature sensor means 200. The desired temperature can be maintained by controlling various variables, including the energy supplied to the infrared lamps and the introduction of heated air into the combustion chamber. Once combustion is fully achieved in the combustion chamber, the reflux of the combustion gases supplies an essential amount of heat which, combined with the heat contained in the fresh combustion air. the air that enters through the ducts 75, 78, constitutes the majority of the heat necessary to support combustion. of the volatile solid material of the mud along the conveyor belt. Once you have reached the combustion chamber. Once a full efficiency combustion has arrived, it will be sufficient that the infrared lamps 73 provide a minimum amount of additional heat.

While the sludge deposited by the feeding apparatus 11 moves with the belt 90, the teeth 124 of the mixing bars 121 break the sludge which, under the intense heat of the combustion chamber, while moving under the infrared lamps, tends to form a crust. The positioning of the mixing teeth, provided in different positions on the mixing bars, ensures the maximum possible contact with the mud that is on the belt so that said teeth are able to mix said mud to expose it optimally to the action of heat.

The flow rates and pressures of the recirculated combustion gases, the air supplied by the supply system 20 and the current induced by the washing bubbler 15 are manipulated so as to ensure that the combustion chamber operates under a certain vacuum with respect to the the ambient atmosphere which surrounds it so as to prevent harmful and annoying fumes from escaping from said chamber during the combustion of solid waste.

Now that the mud has reached the discharge end of the conveyor belt, all the volatile solids contained therein have been incinerated, the small amount of ash remaining being deposited downwards within the lower part of the chimney hopper 130a. The ash falls into the discharge conveyor 133, within which a feeding auger moves the ash towards the bucket elevator 140, through which it is raised and then deposited downwards through the conduit 141 and into the storage tank 142 The ash 15 can be removed from the said storage tank through the lower door 143.

The reflux combustion gases sucked into the exhaust 16, from the feeding end of the combustion chamber, flow through the conduit 150 to the spraying part 20 151 of the scrubber 15. Water leaving the orifices 152 is injected into the combustion gases to cool the latter and separate the solid particles or the ventilated ash transported together with said gases from the combustion chamber. A part of the water and the ventilated ash are 25 discharged from the conduit 156 at the bottom of the tank 154. The latter can comprise compartments for different passages of the combustion gases during which additional water can be sprayed on the gases in flow to cool them further and separate the ventilated ash. The cooled exhaust gases 30 are discharged into the atmosphere through the chimney 161 by the action of the exhaust fan 160. Any part of the sludge that falls through the belt at the entry end of the combustion chamber can be removed and cleaned of from time to time through the removable door 191 which is in the cleaning hopper 190.

the

In the event of failure or malfunction of certain system components relating to the exhaust 16 and / or the combustion chamber, the valve 13 lb can be opened to discharge into the atmosphere through the chimney 13la.

The plant and the process according to the invention allow to incinerate, with high efficiency and in a continuous way, a maximum quantity of sludge in a minimum time and space 45. The use of the heat obtained with infrared rays, both to start the combustion process and to support the combustion itself, is a highly efficient and effective way of feeding a maximum amount of heat with the minimum expense and using a very compact system. Therefore, I know the main source of heat generated in the combustion chamber derives from the combustion of the solid volatile material of the mud with the necessary additional addition of heat supplied by the infrared lamps which provide intense, concentrated and high temperature heat. Furthermore, the initial fragmentation of the sludge to prepare it for the subsequent combustion process is achieved with the use of intense heat produced by infrared lamps.

Although the incinerator and the incineration process have been discussed in relation to the treatment of sewage sludge, it is obvious that other types of waste can also be treated by the same plant and with the same process. In particular, for example the sludge by-product from livestock farms with a high concentration of animals 65 create particularly difficult waste feeding problems, problems which can be solved in the same way described above for sewage sludge. The high concentration of heat obtainable with infrared lamps reduces in

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Essentially the normal heat losses that occur in conventional incinerators.

The system 300 shown in figs. 10-12 is a modified form of that shown in fig. 1 and is suitable for carrying out the initial activation and regeneration or reactivation of activated carbon particles by incineration. The system 300 has essentially the same characteristics and functions as the system 10. However, there is a modified form of supply and exhaust with a modified arrangement for the passage of the cooling air flow of the infrared lamps in order to adapt the system according to the invention is special for the treatment of activated carbon. The combustion chamber 12a, the reflux discharge 16, the gas washing apparatus 15 as well as the other associated appliances are identical to those of the incinerator 10. In the system 300, a supply line 301 of the material to be treated it is connected directly with the combustion chamber to the input end of the conveyor belt 90, to feed the coal to be treated directly into the combustion chamber on the belt without the pre-treatment forms used in the incinerator 10. Fig. 11 represents the structure for insulating the cooling air for the ray lamps from the combustion chamber. The other characteristics of the combustion chamber on the belt without the pretreated forms in flg. 3. With reference to fig. 11, a quartz panel 301 'for each of the casings 70 of the lamps 73 is fixed between said box transversely to the upper part of said combustion chamber in correspondence with its internal and external ceramic coatings, so that the inside of the lamp casings are each isolated from the combustion chamber. The air duct 76 is connected with a vertical exhaust duct 302, which leads to the reflux outlet 16, so that the cooling air for the lamps passes from the duct 75 directly through the lamp housings into the duct 76 and it is then expelled into the gas exhaust system. The quartz panels or barriers 301 'prevent the cooling air of the lamps from entering the combustion chamber 12a. In all other respects, the structure of the combustion chamber is the same as that shown in figs. 1 and 3. Insulation of the cooling air of the lamps in the combustion chamber is particularly necessary when it comes to activated carbon in order to minimize the amount of oxygen to be added to the combustion chamber so as to maintain precise control of the combustion process. combustion in said chamber and preventing the carbon particles themselves from burning after the contaminants contained therein.

At the discharge end of the combustion chamber, the system 300 comprises a cooling tank 303 equipped with a water inlet 304 and an outlet 305 so that the carbon particles treated in the chamber are deposited by the conveyor belt directly into said cooling tank and flow from it in the form of a slime or sludge to suitable plants (not shown) for the final treatment of the activated carbon particles, plants which are not included within the scope of the present invention. A steam supply system 310 is connected to the discharge end of the combustion chamber to feed-steam into the chamber and allow a more precise control of the atmosphere while the treatment of the carbon particles takes place.

A boiler 311 is provided with a steam outlet 312, which leads to the combustion chamber and a water supply line 313. An energy conducting thread 314 leads to the electric heating means, not represented, by the boiler to generate the desired quantity of steam to be fed to the combustion chamber. In all other respects the structure of the incinerator, in correspondence with the casing 130, comprising the chimney 13 la and the associated apparatus, is unaltered with respect to the system 10 shown in fig. 1.

In the operation of the system 300, both for the initial activation 5 of the carbon particles and for the regeneration or reactivation of these particles, the basic purpose of the invention consists in the elimination of all foreign bodies and substances from the coal surfaces and externally and internally of the particles so as to make the maximum quantity of coal surfaces clean and therefore available for adsorption, coal that can be used in the treatment of waste water, water purification and is also used in many other fields application. The diameters of the carbon particles can vary from 0.3 cm (1/8 of an inch) or from the same order of magnitude of the larger dimensions of irregular particles up to minimum sizes e.g. particles that would normally be considered as part of dust. These particles have many empty spaces within which the contaminated attach themselves to the surfaces of the coal during the 20 treatment procedures in which the coal is used. Furthermore, in the initial formation, the voids can contain binding agents so that the particles are bound to each other by said ligands which however must be removed when it is initially desired to activate the carbon to use it. The carbon particles to be treated are introduced into the combustion chamber 12 on the conveyor belt through the conduit 301. When the particles are deposited on the belt, and move along it, they are subjected to heating by the infra-30 ray lamps red, the atmosphere is regulated so as to be slightly under vacuum and a gas counter-flow is established along the combustion chamber and within 1 & 16. To cool the lamps, air is fed from the duct 75 through the lamp housings and within the conduit 76. By means of quartz panels 301 ', air is prevented from entering the combustion chamber, said panels by isolating the casings 70 of the lamps from the said combustion chamber. The ducts 77 and 78 feed the air which may be required for the oxidation necessary for the incineration of the carbon contaminants "in exactly the same way as in the case of system 10.

An essential feature in the treatment of attic carbon in the plant 300 is represented by the control of the atmosphere of the combustion chamber to obtain a condition which allows an essentially complete incineration 45 of the binding agents and / or contaminants according to the case, while there must be no no incineration or at least as little as possible of the carbon particles. Depending on the characteristics of the carbon particles under treatment and the contaminants present in said particles, the atmosphere in the combustion chamber is controlled within a field that goes by itself pure steam air or also different mixtures of air and steam. Air is fed into the sides of the combustion chamber according to the needs through ducts 77 and 78 while steam is fed through line 312 which 55 comes from boiler 311. As it moves along the conveyor belt under the infrared lamps and within the desired atmosphere of the combustion chamber, the coal is heated by said lamps to a temperature that can vary between 540 ° C (1000 ° F) and 980 ° C (1800 ° F) and is constantly stirred or agitated by the teeth 124 of the scrambling bars 120. During the advance of the coal from the point where it was deposited on the conveyor belt to the end of the belt within the combustion chamber, the contaminants and / or the binding agents are substantially burned all 65 away from the surfaces of the coal, the counter-current of the combustion gases increasing the reactivation and at the same time reducing the amount of heat needed that would otherwise have to be fo supplied by infrared lamps. Yes

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they discharge the carbon particles from the end of the conveyor belt into the casing 130 into the cooling shutdown tank 303, which shuts off any substance that is still burning. The particles and the water of the extinguishing tank flow through the pipeline 305 to the subsequent treatment plants of the particles according to the necessary standardized procedures which are not part of the present invention.

The surfaces of the carbon particles are completely cleaned making them ready to be used for the first time in the case of initial activation and restored to use in the case of a regeneration process, which leads them to recover the same active area they had originally in virgin coal. They will thus be suitable for use in the various treatment processes which make use of activated carbon. By this process it is possible to remove the foreign substances from the carbon particles with a lower carbon loss than in any other presently known and conventional system for activating or reactivating activated carbon. In addition to this high-performance removal of foreign materials by incineration with minimal carbon loss, there is the further advantage that the time required for said treatment is essentially less than that required in known processes and equipment. The possibilities of accurately controlling the temperatures far exceed those in conventional systems and the time required to put the system into operation is correspondingly much less. The considerably higher efficiency allows the use of electricity, the total cost of energy being substantially the same as that which would be obtained using natural gas.

Using natural gas in currently known and conventional systems, for the regeneration of coal, approx. 8000 BTU per pound while instead using infrared heating lamps you get the regeneration of every pound of coal using only approx. 2000 BTU.

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Claims (17)

622 090 1. Plant for continuous treatment with infrared rays of materials having volatile components, in particular for the incineration of sewage sludge and for the initial activation and regeneration of activated carbon particles, characterized 5 by what it comprises: - a box (12) which delimits an elongated cumbusting chamber (12a), having at one end an entrance opening and at the other end a discharge opening; - a conveyor belt (90) mounted on rollers (103) which make it 10 move within said combustion chamber (12a) and having an upper part of belt suitable for advancing the materials to be treated within and along said combustion chamber (12a) from said inlet opening to said discharge opening and furthermore provided with a part of return belt arranged lower than said part of upper belt; - infrared heating means (73) mounted on said box (12) and adapted to radiate heat on said materials which are on said conveyor belt (90) while the latter advances said materials along said 2nd combustion chamber, combustion gases are released from said materials due to the heating caused by said infrared rays; - loading means (11) connected with said box (12) to the inlet opening of said combustion chamber (12a) to receive the materials from a supply point (21) and adapted to M unload said materials on said belt conveyor (90) located in said chamber (12a); means (14) for removing the treated materials from said combustion chamber (12a) at the discharge opening of the same chamber; 30 means (20) connected to said body (12) for pushing forcefully (80) ambient air into said body; - means (16) adapted to create a draft at the combustion chamber inlet opening in order to cause a backflow of the mixture composed of air and combustion gas 35, said mixture flowing back parallel and above said materials, from the zone discharge in the direction of said material inlet opening; - and means (200) for temperature detectors arranged inside said container (130) above said conveyor belt and connected (201) to control means (52) for varying the temperature of said mixture in counter-current, controlling the intensity of emission of the ray heating means (73). 2. Plant according to claim 1, characterized in that it comprises means (75, 76) for supplying air 45 along said infrared heating means (13) in order to cool the latter (77, 78 ) and channeling the air inside said combustion chamber (12a) to feed the latter with combustion support air. 2 3 622 090 to provide a part of the heat required to dry and burn said materials; is - varying the temperature of said reflux mixture by means of a control (200, 52) of said ray heating means (73). System according to claim 2, characterized in that the control means (74, 52) regulate said infrared heating means (73) in order to supply concentrated caloric energy with a temperature ranging from 640 ° C to 930 ° C . 4. Plant according to claim 1, characterized in that it comprises: - an internal insulating coating (62, 63) inside said body and around said chamber to retain heat therein; - a conveyor belt (90) mounted movably on rollers (91) arranged transversely with respect to said combustion chamber and connected with the opposite side walls (61) of said body, which support said conveyor belt, an upper part of the latter moving along said body (12) within said chamber for supporting the materials during combustion which takes place in said chamber and a return part of said belt arranged under said upper support part; said rollers comprising tension rollers at the ends opposite and intermediate rollers (91) for supporting said upper part and said lower part of said belt; means (92, 93.94) for operating said conveyor belt (90) so that said upper part of the belt moves from said inlet opening to said discharge opening of said chamber; - a flue gas discharge duct (16) connected with the inlet opening of said box (12) to make the combustion gases flow back into said chamber along said upper part of the conveyor belt. 5. Plant according to claim 4, characterized in that it further comprises: - a supply duct (75) connected with a fan (80) to supply said combustion chamber (12a) with air for combustion. 6. Plant according to claim 4, characterized in that it comprises ducts (77, 78) for supplying combustion air, connected with the interior of said combustion chamber (12a), arranged along said conveyor belt (90), which flow under said ray heating means (73). Plant according to claim 5, characterized in that it comprises an air inlet valve (77b, 78b) which is interposed between said combustion chamber (12a) and said air supply ducts (20), and means for varying the position of said valve. 8. Procedure for commissioning the system according to claim 1, characterized in that it comprises the following operations: - supporting said materials on a mobile belt (90) within a box (12) which defines a combustion chamber (12a); - striking with infrared radiation (73) said materials while moving on said belt along said combustion chamber; - causing the combustion gas to flow back in counter current along said combustion chamber in a direction opposite to the direction of movement of said belt while said materials are treated on it and inside said chamber. Method according to claim 8, characterized in that it comprises the operation of blowing the cooling and oxidation air inside said box (12) along infrared heating means (73) in order to cool said means ( 73) for heating and supplying heated air inside said container. 10. Process according to claim 9, characterized in that said waste products are heated up to a temperature between 650 ° C and 930 ° C. 11. Process according to claim 10, characterized in that it comprises the operations of: - introducing said materials into the elongated combustion chamber (12a); moving said materials on a conveyor belt (90) supported on rollers (103) along said combustion chamber from said inlet opening to said discharge opening; - striking with infrared rays said materials which are found on said conveyor belt while the latter moves said materials along said combustion chamber, from said materials releasing combustion gases due to the heating effected by said infrared rays; - removing (14) said materials treated by said combustion chamber (12a) at the discharge end of said chamber; - forcing (80) ambient air into said body (12); - creating a draft (20) at the inlet opening in order to create a mixture of reflux air and combustion gas, said reflux mixture flowing over and generally parallel to said materials from the region of said discharge opening to said entrance opening for the purpose 55 60 12. Process according to claim 8, for the initial activation and regeneration of activated carbon particles, in which the plant has means for controlling the atmosphere in the combustion chamber, characterized by what (it) comprises the operations of : - supporting said carbon particles on the belt (90); - striking with infrared rays (73) said carbon particles while the latter move along said combustion chamber (12a) by the action of said belt to burn said foreign substances out of said particles; - controlling the atmosphere in said combustion chamber around said carbon particles in order to carry out the combustion of essentially all foreign substances outside said carbon particles and at the same time making sure that the carbon particles themselves do not burn (fig. 10). Method according to claim 12, characterized in that said atmosphere is controlled by introduction of steam (310) into said combustion chamber (12a). 14. Process according to claim 12, characterized in that said carbon particles are heated by said infrared radiation (73) up to a temperature between 530 ° C and 970 ° C. Method according to claim 12, characterized in that said atmosphere is controlled by introducing air (77, 78) into the combustion chamber. Method according to claim 13, characterized in that said atmosphere is controlled in said combustion chamber by introducing air (77, 78) and steam (310) into the latter. 17. Process according to claim 12, wherein the plant comprises a gas discharge duct, characterized in that it comprises the operations of: - maintaining a depression within said combustion chamber; - causing the combustion gases generated by the application of said infrared radiation to flow into the gas discharge duct (16).