System for solid waste treatment by thermal hydrolysis and method for solid waste treatment that uses said system

Abstract

The present invention discloses an autoclave assembly, a system for solid waste treatment by thermal hydrolysis comprising at least two autoclave assemblies and a method for solid waste treatment by thermal hydrolysis using the system for solid waste treatment by thermal hydrolysis. The present invention solves all the problems associated with the treatment of the "complex" solid waste (composition of fibrous materials, such as textile and plastics), with advantages such as: being able to use a single inlet / outlet point of the treatment container located at the bottom, thereby saving in infrastructure, harnessing the storage capacity of the vertical arrangement, using conveyor systems that provide good fluid dynamics without clogging, avoiding the winding of fibrous materials and using a system configured to mobilise all the solid waste accumulated in the vertical container, allowing internal recirculation during the treatment that substantially improves heat transfer.

Description

[0001] SOLID WASTE TREATMENT SYSTEM BY THERMAL HYDROLYSIS AND SOLID WASTE TREATMENT PROCEDURE IT USES

[0002] SAID SYSTEM

[0003] TECHNICAL FIELD OF THE INVENTION

[0004] The present invention belongs to the technical field of solid waste treatment at an industrial level.

[0005] More specifically, the present invention relates to an autoclave assembly, to a solid waste treatment system by a thermal hydrolysis process that has at least two autoclave assemblies, as well as to a solid waste treatment method that employs the system.

[0006] BACKGROUND OF THE INVENTION

[0007] Numerous industrial systems and methods for solid waste treatment are known, such as, for example, those disclosed in European patent EP2519362, owned by the applicant. Said document discloses a solid waste treatment system comprising a reactor, or autoclave, equipped with an external container configured to house solid waste under pressure, inside which is arranged an inverse rotor comprising two coaxial cylindrical tubes, provided with helical blades that rotate in opposite directions. In some embodiments of the invention, the treatment system, in addition to the reactor, may also comprise other autoclaves, which act as an inlet chamber, transit chamber or outlet chamber, which are also arranged horizontally and equipped with an internal screw-type conveyor.Furthermore, these autoclaves are placed one on top of the other thanks to a vertical support structure.

[0008] Additionally, the state of the art provides an autoclave assembly for sterilizing medical waste and its operating method, as disclosed in PCT patent application publication number W02013 / 050822A1. The autoclave assembly disclosed in said PCT has the waste inlet at the top of the autoclave assembly. This is a limitation in terms of the height of the autoclave assembly, since the greater the height, the more energy is required to raise the medical waste to the top of the autoclave assembly. Furthermore, the autoclave assembly disclosed in the PCT agitates the waste by rotating an auger that has arms or rods with scrapers fixed to them and distributed along the entire length of the auger to agitate all the material stored in the sterilization chamber.This system would not be suitable for treating complex waste such as MSW (Municipal Solid Waste) or other waste containing fibrous materials such as textiles, plastics, etc., which would become wrapped around the arms and scrapers, causing an excessive increase in the electrical consumption of the "M" gearmotor and causing the auger to stop. Furthermore, slow agitation of complex solid waste does not significantly improve the heat transfer of the vapor that condenses in the solid waste.

[0009] The sector needs to increase the efficiency of solid waste treatment systems and procedures, as well as their steam and treated water consumption. Furthermore, it would also be desirable to reduce the plant space required for installation and reduce system complexity, resulting in a lower probability of failure and lower investment requirements, resulting in a more robust system.

[0010] TECHNICAL PROBLEM TO BE SOLVED

[0011] The present invention, unlike the solutions of the state of the art, solves the technical problem of how to treat urban solid waste (MSW) containing fibrous materials such as textiles, plastics, etc., since it would be wound around the lower outlet of the vertical autoclave assembly. For example, in the PCT document with publication number W02013 / 050822A1 cited in the section on the state of the art, urban solid waste containing fibrous materials such as textiles and plastics would be wound around support "25" and bearing "8a", blocking the passage of material.

[0012] The present invention solves all the problems presented by the treatment of “complex” solid waste (composition of fibrous materials such as textiles, plastics, etc.) such as MSW (Urban Solid Waste), presenting the following advantages:

[0013] • Storage in a vertical container with waste loading / unloading through the same opening located at the bottom. This reduces the installation footprint and the cost of the necessary conveyors (reducing CAPEX).

[0014] • Treatment in vertical vessels also allows for much greater utilization of storage capacity compared to horizontal autoclave systems. This also results in a reduction in footprint and CAPEX.

[0015] • Screw conveyor system designed for good fluid dynamics without jamming by having free ends without any type of shaft support that would cause wrapping of fibrous materials.

[0016] • Vertical screw conveyor with specially designed blades to move all the solid waste accumulated in a vertical container, allowing, on the one hand, its internal recirculation during the treatment process and, on the other, its complete discharge after treatment. Internal recirculation allows the solid waste to precipitate in a cascade once it reaches the top of the screw conveyor, which greatly improves heat transfer. Furthermore, these blades also have the advantage of shearing soft materials such as organic matter, which reduces their particle size and improves the thermohydrolysis treatment process.

[0017] DESCRIPTION OF THE INVENTION

[0018] The present specification discloses an autoclave assembly, a thermal hydrolysis solid waste treatment system comprising at least two autoclave assemblies, and a method for treating solid waste by thermal hydrolysis using the thermal hydrolysis solid waste treatment system, according to a first, second, and third aspect of the invention, respectively. Throughout this specification, the terms "pretreatment material", "solid waste", and "solid municipal waste" have the same meaning: solid waste to be treated whose composition may contain fibrous materials such as textiles, plastics, etc.

[0019] The present invention aims to address all of the above-mentioned problems.

[0020] In a first aspect of the invention, an autoclave assembly is disclosed for the treatment of solid waste by thermal hydrolysis, the autoclave assembly comprising: a vertical container, with a lower part in the shape of an inverted truncated cone, which is configured to house solid waste under pressure; where the vertical container comprises: o a first common inlet / outlet area for solid waste located at the bottom of the vertical container, below the bottom of the vertical container; o a lower discharge area for treated solid waste; o a steam inlet and a steam outlet located at the top of the vertical container, configured to pressurize and depressurize the vertical container with pressurized steam from a thermal hydrolysis process; a first horizontal conveyor comprising a solid waste inlet and a horizontal auger,which conveys solid waste from the solid waste inlet of the first horizontal conveyor to the solid waste inlet / outlet of the vertical container; a second vertical conveyor comprising a vertical auger inside the vertical container configured to transport the solid waste by means of a downward flow and an upward flow; where the downward flow discharges the solid waste; where the vertical auger has an axis and helical blades along the entire axis, where the helical blades have a diameter smaller than the diameter of the vertical container and comprises, at the height of the lower part in an inverted truncated cone shape, sweeping blades whose diameter extends to the inner perimeter of the vertical container without contact with it in such a way that they allow all the solid waste stored in the vertical container to be mobilized so that,Depending on the direction of rotation of the gear motor to which the vertical auger is connected, a rotation of the vertical auger that causes a downward flow allows the treated solid waste to be discharged, while a rotation of the auger that causes an upward flow allows feeding and internal recirculation of the solid waste, facilitating its treatment by falling by gravity from the upper end of the vertical auger since, by dispersing in the form of "rain" or "cascade", the contact surface with the process steam increases, which results in a considerable improvement in the heat transfer phenomena.

[0021] The design of the sweeping blades, whose diameter extends to the inner perimeter of the vertical container without contact with it, prevents compaction of the solid waste and ensures that all the solid waste circulates through the vertical auger due to the thrust generated by the blades on the solid waste from the periphery of the vertical container (that is, from the area closest to the inner surface of the vertical container) to the axis of the vertical auger.

[0022] This thrust generated by the blades, as mentioned above, also generates an additional effect, beneficial to the process. This effect is the shearing that occurs in white materials such as organic matter, breaking down fibers and therefore reducing the particle size of the material being treated. This increases the contact surface of the solid waste with the direct steam, improving the thermohydrolysis treatment.

[0023] In one embodiment of the invention, the vertical container additionally comprises an auxiliary feed inlet at the top of the vertical container. This makes it possible to supply a new load to the vertical container via a solid waste conveyor.

[0024] In another embodiment of the invention, the helical blades of the vertical auger comprise a helical rim around the perimeter, which, once the level of solid waste stored inside the vertical container is exceeded, helps to retain the solid waste that rises to the upper end of the vertical auger, thus maximizing the flow that falls in the form of a cascade and, therefore, the heat transfer from the steam to the solid waste. That is, the solid waste transported by the vertical auger is confined by the waste itself stored inside the vertical container (the auger creates a drill effect) but may require the rim on the helical blades to retain it above said level of stored waste in order to maximize the flow that precipitates from the upper end of the vertical auger.

[0025] In another embodiment of the invention, the autoclave assembly additionally comprises at least one blade arranged on the inner surface of the upper end of the vertical container and intended to cut and detach any fibrous material that may remain wound during rotation.

[0026] In another embodiment of the invention, the first horizontal conveyor and the second vertical conveyor each comprise motors supported by drive towers, where the respective motors are connected to the horizontal auger and the vertical auger, respectively, thereby causing the rotational movement of the horizontal and vertical augers. However, the horizontal auger only operates in a rotational direction to feed untreated solid waste into the pressure vessel.

[0027] In another embodiment of the invention, the vertical auger has a low rotation speed. In particular, the rotation speed of the vertical auger is between 5 and 30 rpm.

[0028] In another embodiment of the invention, the steam outlet of the vertical vessel is connected to a vacuum system configured to depressurize the autoclave assembly before opening it to the atmosphere for feeding or discharging treated solid waste.

[0029] In another embodiment of the invention, the steam inlet of the vertical vessel is connected to a steam generator that produces pressurized steam.

[0030] In another embodiment of the invention, the vapor inlet and outlet is carried out through the same connection to the vertical container with the interposition of a self-cleaning filter.

[0031] In another embodiment of the invention, the solid waste inlet / outlet of the vertical container has stops that guide the vertical auger, keeping the lower tip of the auger shaft free, that is, without any type of bearing or bushing with support.

[0032] The horizontal conveyor for feeding solid waste to the vertical container features a shaftless auger that rests on its own sleeve at its end opposite the gearmotor. That is, like the lower end of the vertical auger, the horizontal auger also has no support, which prevents material entanglement and greatly improves fluid dynamics.

[0033] In a second aspect of the invention, a system for treating solid waste by thermal hydrolysis is disclosed. The system is provided with at least two autoclave assemblies, both with vertical vessels. Thanks to its particular configuration and the elements comprising it, it is possible to reduce the number of cycles required for proper treatment, which translates into lower steam consumption and a longer useful life of the mechanical elements. Furthermore, the system according to the invention allows for an increase in the effective residence time of the solid waste compared to previously known systems and is capable of varying said residence time depending on the specific needs of the waste to be treated.Furthermore, the treatment system according to the present invention, by using two interconnected and synchronized sets, manages to reduce steam consumption by recovering the depressurization steam by heating a new batch of waste in the second autoclave set.

[0034] An additional advantage is that it not only allows for a greater reduction in steam consumption, but also reduces the treated water and wastewater generated during thermal hydrolysis, derived from condensates, compared to state-of-the-art treatment systems. It should be noted that this only occurs if these waste vapors are used to preheat a new batch of waste; otherwise, the vapors are condensed and stored for further treatment.

[0035] Therefore, the solid waste treatment system by thermal hydrolysis comprises at least a first autoclave assembly and a second autoclave assembly, both autoclave assemblies as defined in any one of the embodiments of the first aspect of the invention. The steam inlet / outlet of the vertical vessel of the first autoclave is connected to the steam inlet / outlet of the vertical vessel of the second autoclave and to the vacuum system by means of valves, one for each steam inlet / outlet and a third before the vacuum system. This set of valves can be used to control both the recovery of the steam that passes due to the pressure difference from one pressurized autoclave assembly to another that is at atmospheric pressure with a new batch of solid waste, and to finally completely depressurize the autoclave assembly by extracting the mixture of residual steam and non-condensables by means of the vacuum system.

[0036] The system includes various control and monitoring devices, including level sensors for controlling the filling / emptying level by activating or stopping the gearmotor of the horizontal feed conveyor, a pressure sensor for controlling pressure by regulating the corresponding steam inlet / outlet valves, and a temperature sensor for monitoring the treatment temperature.

[0037] This allows for a fully automated process through the control of various parameters, resulting in greater safety and lower operating costs by minimizing user interaction. For example, this way, the inflow and outflow of solid waste is completely automated. This ensures that the necessary safety conditions are in place before the container is accessible, and the process parameters are appropriate for loading and unloading the entire system.

[0038] Because the thermal hydrolysis process carried out inside the assembly operates under high pressure and temperature parameters, it is extremely important to ensure that these are adequate before opening the assembly. Pressure, in particular, is an extremely important parameter to consider from a safety perspective, given that, when proceeding with the opening cycle, failure to ensure adequate pressure can pose significant risks to the safety and health of operators. For example, if this pressure were very high, the tank, upon opening, could cause a violent and uncontrolled release of pressure, endangering the safety of operators working in the vicinity of the assembly. Furthermore, if this were to occur at high temperatures, it would pose additional risks due to the heat released.

[0039] On the other hand, it should also be noted that from the point of view of device operation, monitoring of certain process parameters and the degree of automation described also improves performance, allowing the process to be acted upon in such a way as to maintain optimal values ​​throughout the treatment of solid waste by means of thermal hydrolysis.

[0040] The third aspect of the invention discloses a method for treating solid waste by thermal hydrolysis, which employs the solid waste treatment system by thermal hydrolysis of the second aspect of the invention. The method comprises the following steps, of predetermined duration: a) loading, into the first autoclave assembly, a new batch of solid waste through the solid waste inlet of the first horizontal conveyor and operating the horizontal auger and the vertical auger until the solid waste reaches, preferably and at most, between 70% and 90% of the volume of the vertical container; in this step, the steam inlet and steam outlet valves are closed, as well as the outlet valve for the treated solid waste, which is also closed; the horizontal auger is stopped by stopping the horizontal auger gearmotor;b) compensating for the pressure in the first autoclave assembly with a second autoclave assembly located in step "d)"; for which purpose: connecting both autoclave assemblies by opening the corresponding residual steam inlet / outlet valves, keeping the vertical auger rotating in the direction of rotation to create an upward flow of solid waste, increasing the heat exchange surface with the residual steam due to the cascade effect that occurs when the solid waste falls from the top of the vertical auger; in this way, due to the pressure difference, a flow of residual steam is created from the second autoclave assembly to the first autoclave assembly, finally almost completely depressurizing the second autoclave assembly, while in the first autoclave assembly, practically all of the steam is used to preheat the solid waste recently fed in step a);In this step, the steam inlet valve is closed and the steam outlet valve is open; the treated solid waste outlet valve and the pretreatment material inlet valve are closed; c) pressurizing the first autoclave assembly to the treatment pressure by injecting steam from the steam generator, which entails heating the solid waste to the temperature corresponding to the saturated steam pressure; in a first sub-stage, the first autoclave assembly is pressurized and the solid waste is heated; in a second sub-stage of this step "c)", the conditions are maintained to give the predefined residence time;The operation of the vertical auger of the first autoclave assembly, with the motor rotating clockwise for upward flow, allows for the creation of a recirculation of the solid waste, increasing the heat transfer surface with the residual steam due to the cascade effect that occurs when the solid waste falls from the top of the vertical auger; in this way, all the solid waste quickly reaches its treatment temperature, while producing a mechanical effect that breaks down the organic matter without breaking up the heavy impurities; in this step, the steam outlet valve, the treated solid waste outlet valve, and the solid waste inlet valve are kept closed, and the steam inlet valve is open;(d) equalize the pressure with the second autoclave assembly, which is currently in step “a)” with a new batch of solid waste loaded and at atmospheric pressure. The operation of the vertical auger of the first autoclave assembly, with the motor rotating clockwise for upward flow, allows for the creation of a recirculation of the solid waste, increasing the flashing (release of vapor from a superheated wet liquid or solid when the pressure of the process atmosphere in which it is located is reduced) due to the cascade effect that occurs when the solid waste falls from the top of the vertical auger;In this way, due to the pressure difference, a flow of residual steam is created from the first autoclave set to the second autoclave set, finally achieving almost complete depressurization of the first autoclave set, while in the second autoclave set, practically all the steam is used to preheat the solid waste recently fed in step "a)"; in this step, the steam inlet valves, the treated solid waste outlet valve and the solid waste inlet valve are kept closed, and the steam outlet valve is open;e) depressurize the first autoclave assembly which, after the previous step (step "d)"), was slightly pressurized mainly due to the presence of non-condensables that must be removed by means of a vacuum system specifically designed for this purpose. The operation of the internal vertical auger of the first autoclave assembly, with clockwise motor rotation for upward flow, allows a recirculation of the solid waste to be created, increasing the flashing due to the cascade effect that occurs when the material falls from the top of the auger; in this way, due to pressure differences, a mixed flow of non-condensables and residual steam is created towards the vacuum system, which allows the autoclave assembly to be completely depressurized to atmospheric pressure;In this step, the steam inlet valve, the treated solid waste outlet valve, and the solid waste inlet valve are kept closed, and the steam outlet valve is open; f) discharging the batch of treated solid waste toward the discharge conveyor (not shown) which would be just below the treated solid waste outlet valve; unlike all the previous steps, in this step the vertical auger of the first autoclave assembly is rotated in the appropriate rotation direction to cause a downward flow of the treated solid waste toward the treated solid waste outlet valve located at the bottom of the lower cone of the first autoclave assembly.

[0041] Optionally, step "a)" additionally comprises extracting the gas contained in the autoclave assembly, especially the air that entered with the loading of the new batch of waste, by means of its aspiration through the vacuum system. This improves heat transfer in the subsequent steps (steps "b)" and "c)") of direct steam treatment. To this end, the solid waste inlet and outlet valves would be closed, as would the steam inlet valve, while the gas outlet valve to the vacuum system would be open. Regarding the screw conveyors, the horizontal material feed screw would be stopped, while the vertical screw could be stopped or operating in the direction of rotation for upward solid waste flow, allowing recirculation, releasing the gases trapped between the solid waste particles.

[0042] BRIEF DESCRIPTION OF THE FIGURES

[0043] To complete the description of the invention and in order to help better understand its characteristics, according to a preferred embodiment of the same, a set of drawings is attached in which, for illustrative and non-limiting purposes, the following figures have been represented:

[0044] FIG. 1.- Shows an autoclave assembly for the treatment of solid waste by thermal hydrolysis according to an embodiment of the present invention.

[0045] FIG. 2.- Shows an isometric view of the blades fixed to the vertical auger inside the container.

[0046] FIG. 3.- Shows a plan view of the blades fixed to the vertical auger inside the container.

[0047] FIG. 4.- Shows a solid waste treatment system by thermal hydrolysis comprising two autoclave assemblies according to the present invention.

[0048] FIGS. 5 - 10.- Show the operation of the autoclave assembly for the solid waste treatment method by thermal hydrolysis of the present invention.

[0049] DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

[0050] 1 T. - Autoclave set;

[0051] 2 Autoclave assembly system;

[0052] 3 Vertical Container; 3' cylindrical upper part; 3" truncated cone lower part;

[0053] 4 first common solid waste inlet / outlet area, located at the bottom of the vertical container; 4': guide stops; 5 vertical auger (second vertical conveyor); 5': blades; 5": helical edging;

[0054] 6 sweeping blades;

[0055] 7 Drive headframe of the vertical auger support;

[0056] 8 Vertical auger gearmotor;

[0057] 9 Blade or blades, provided on the inner surface of the upper end of the vertical vessel; The blades may incorporate a deflector or deflectors;

[0058] 10 Self-cleaning basket filter (connected to clean steam inlet and residual steam outlet valves); 10': steam inlet; 10": steam outlet.

[0059] 11 Auxiliary power input

[0060] 12 First horizontal conveyor; 12': Envelope of the first conveyor;

[0061] 13 Horizontal auger without shaft (first conveyor);

[0062] 14 Drive headframe of the horizontal auger support;

[0063] 15 Horizontal auger gearmotor;

[0064] 16 Treated solid waste outlet valve; 16': treated solid waste outlet;

[0065] 17 Solid waste inlet valve; 17': solid waste inlet;

[0066] 18 Steam boiler;

[0067] 19 Vacuum system;

[0068] 20 Solid waste;

[0069] 21 Treated solid waste;

[0070] 22 Steam inlet valves 22', 22”;

[0071] 23 Steam outlet valves 23', 23”.

[0072] Fig. 1 shows the autoclave assembly 1, T for the treatment of solid waste by thermal hydrolysis according to an embodiment of the present invention. The autoclave assembly 1, T comprises the vertical and circular container 3. The vertical and circular container 3 has the upper part 3' in a cylindrical or truncated cone shape forming the angle "a" with respect to the longitudinal axis of the container that coincides with the geometric axis of the cylindrical shape of the upper part 3'. Additionally, the vertical and circular container 3 comprises the lower part 3" in an inverted truncated cone shape that connects with the common solid waste inlet / outlet area 4 of the vertical container 3. Said common solid waste inlet / outlet area 4 of the vertical container 3 has a cylindrical shape and at its lower end has the solid waste outlet 16' whose opening and closing is actuated by the solid waste outlet valve 16.Additionally, the common solid waste inlet / outlet area 4 of the vertical container 3 has stops 4' that guide the vertical auger 5, keeping the lower end of the auger shaft 5 free, that is, without any type of bearing or support bushing. This prevents any obstruction (normally due to the solid waste wrapping around the end of the auger shaft) at the outlet of the vertical container 4 through the solid waste outlet valve.

[0073] The vertical vessel 3 has the vertical auger 5 that runs longitudinally inside the vertical vessel 3, which is supported by the drive head 7 and is driven by the gear motor 8. The drive head 7 and the gear motor 8 are located above the top of the vertical vessel 3 so as not to come into contact with the steam and the solid residue from the process. To prevent fibers or other components of the solid residue from wrapping around the top of the vertical conveyor shaft 5 at the top of the vertical vessel and inside it, one or more blades 9 may be provided (see Fig. 1). Continuing with the top of the vertical vessel 3, the vertical vessel 3 comprises the filter 10 which in turn has the steam inlet 10' and the steam outlet 10". The filter 10 shown in FIG.1 is a self-cleaning basket filter since the clean steam flow used for the process is contrasted with the dirty residual steam flow that is extracted once the thermohydrolysis process is complete.

[0074] At the top of the vertical container 3 there is also the auxiliary feed inlet 11 , which allows solid waste to be introduced through the top of the vertical container 3. The vertical auger 5, at the height of the lower part 3” in an inverted truncated cone shape of the vertical container 3, has the sweeping blades 6 (see Figs. 1 to 3), which together with a low rotation speed of the auger 5, have the technical effect of carrying the solid waste to the auger 5, which creates a recirculation of all the material stored in 3. The sweeping blades 6 have a diameter that extends to the inner perimeter of the lower part 3” in an inverted truncated cone shape of the vertical container 3, without contact with it (3”). The vertical auger 5 has the helical blades 5', which transport the solid waste to the upper end of the auger 5 or in the opposite direction of rotation allow the waste to be transported to the discharge.The vertical auger assembly 5, the vertical auger support drive frame 7 and the vertical auger gear motor 8, together with the elements of each of them, form the “second conveyor”.

[0075] Continuing with FIG. 1 , the autoclave assembly 1 ,T comprises the first conveyor 12, which has a cylindrical shape and is arranged horizontally. The first conveyor 12 has the casing 12', which internally has the horizontal auger 13. The horizontal auger 13 has no axis, being guided by the interior of the casing 12'. In addition, the auger 13 is moved by the horizontal auger gearmotor 15, which is supported by the drive frame of the horizontal auger support 14 and connected to one end of the auger 13. On the casing 12' and outside thereof, the solid waste inlet 17' is located, the opening / closing of which is actuated by the solid waste inlet valve 17. The solid waste inlet 17' is used to receive the solid waste. The other end of the first conveyor 12 is connected to the inlet / outlet 4 of the vertical container 3.In this way, the solid waste introduced through the solid waste inlet valve 17 is moved to the first common solid waste inlet / outlet area 4 of the vertical container 3 without obstructions because the horizontal auger 13 has no shaft. This prevents obstructions caused by windings, which occur in conventional shaft-based augers.

[0076] The autoclave assembly 1,1' is sealed, allowing its pressurization to carry out a solid waste treatment method by thermal hydrolysis.

[0077] The helical blades 5' may comprise a helical rim 5" around the perimeter that helps the solid waste transported by the blades 5' reach the upper end of the vertical auger 5. The rim helps prevent the pretreatment material (solid waste), which is transported upwards by the vertical auger, from being released from the height corresponding to the level of solid waste stored inside the container. Below said height, the solid waste inside the auger is confined by the solid waste stored on the periphery and therefore the vertical transport of all the material is ensured.

[0078] Alternatively to the blade(s) 9, a deflector (not shown) could also be arranged on the inner surface of the upper end of the vertical container 3, intended to detach and distribute the solid waste raised by the second vertical conveyor.

[0079] The vertical auger gearmotor 8 can rotate the vertical auger 5 in both directions, respectively, while the horizontal auger gearmotor 15 rotates the horizontal auger 13 in the feed direction. The low rotation speed also reduces the power consumption of the vertical auger gearmotor 8.

[0080] FIG. 4 shows an exemplary embodiment of a thermal hydrolysis solid waste treatment system 2 according to the present invention. The system 2 comprises two autoclave assemblies 1 and 1' as described above in FIGs. 1 to 3. As can be seen in FIG. 4, both autoclave assemblies 1 and T are connected to a steam generator 18, which generates pressurized steam that reaches the filters 10 of both autoclave assemblies 1 , 1' through the conduits 10'. The amount of steam circulating from the steam generator 18 to each of the autoclave assemblies 1 , T is controlled by valves 22 (main), 22' (for autoclave assembly 1) and 22" (for autoclave assembly T).

[0081] The residual steam outlet of the vertical container 3 is connected to a vacuum system 19 by conduits 10” intended to facilitate the depressurization of the autoclave assembly 1 , T before its opening to the atmosphere for the feeding of a new batch of solid waste 20 (solid waste - solid urban waste) or discharge of a batch of treated solid waste 21. The quantity of residual steam circulating from each of the autoclave assemblies 1 , T to the vacuum system 19 and the quantity of residual steam circulating between the autoclave assemblies 1 , 1', is controlled by valves 23 (main), 23' (for autoclave assembly 1) and 23” (for autoclave assembly 1').Advantageously, the steam inlet and outlet is carried out through the same connection to the vertical container 3, through the basket filter 10 which, in this way, becomes self-cleaning by introducing the clean steam (which comes from the steam generator 18) in the opposite direction to the residual steam that comes out during depressurization towards the vacuum system 19 or another autoclave assembly.

[0082] In FIGS. 5 to 10, the thermal hydrolysis solid waste treatment method of the present invention is disclosed, applied to the thermal hydrolysis solid waste treatment system of FIG. 4. The method comprises the following steps, of predetermined duration:

[0083] Step 1: (FIG.5) loading, into the autoclave assembly 1 , a new batch of solid waste 20 through the solid waste inlet 17' of the first horizontal conveyor 12 and driving the horizontal auger 13 and the vertical auger 5 until the solid waste 20 preferably and at most reaches between 70% and 90% of the volume of the vertical container (it is necessary to leave a free volume at the top to facilitate the transfer of heat from the steam to the pretreatment material); the horizontal auger 13 and the vertical auger 5 are driven by driving the gearmotor 8 and 15 ("on" state = represented with a white background), respectively; In this step, valves 22' and 23' are closed (“closed” state = represented in black completely) as well as outlet valve 16 (“closed” state = represented with an “x” inside) and outlet 16' which are also closed.In this step, the waste inlet valve 17 is also open (“open” state = represented with a white background).

[0084] Optionally (FIG. 6), the gas contained in the autoclave assembly, especially the air that entered with the loading of the new batch of waste, can be extracted by vacuum aspiration. This improves heat transfer in the subsequent steps, where direct steam treatment takes place. To achieve this, the solid waste inlet and outlet valves would be closed, as would the steam inlet valve, while the gas outlet valve to the vacuum system would be open. Regarding the conveyors, the horizontal material feed auger is stopped, while the vertical auger could be stopped or operating in the direction of rotation for upward solid waste flow, allowing recirculation, releasing the gases trapped between the solid waste particles.

[0085] Step 2: (FIG. 6) equalize the pressure, in the autoclave assembly 1 , with the autoclave assembly T located in step 4; that is, communicate both autoclave assemblies 1, opening the inlet / outlet valve 23' (“open” state = represented with a white background) of residual steam, keeping the vertical auger 5 rotating, by means of actuating the gear motor 8, in the appropriate rotation direction to create an upward flow of solid waste, increasing the heat exchange surface with the residual steam by the cascade effect that occurs when the solid waste falls from the top of the auger 5;in this way, due to the pressure difference, a flow of residual steam is created from the autoclave assembly 1' to the autoclave assembly 1 to finally almost completely depressurize the autoclave assembly T, while in the autoclave assembly 1 practically all the steam is used to preheat the solid waste just fed in step 1; the horizontal auger 13, by means of its gearmotor 15, is stopped ("stopped" state = represented with an "x" inside); in this step, the steam inlet valve 22' is closed; the treated solid waste outlet valve 16 (and the treated solid waste outlet 16'), the inlet valve 17 ("closed" state = represented with an "x" inside) and the inlet 17' are closed. Step 3: (FIG. 7) pressurize the autoclave assembly 1 to the treatment pressure by injecting steam from the steam generator, which entails;in a first sub-stage, the autoclave assembly 1 is pressurized and the solid waste is heated to the temperature corresponding to the saturated steam pressure; in a second sub-stage of this step 3, the conditions are maintained to give the required residence time based on the specific treatment requirements decided on for each project (greater or lesser decomposition, sanitation, sterilization, etc.); the operation of the vertical auger 5, by means of the actuation of the gearmotor8, inside the autoclave assembly 1, with the motor rotating in the appropriate direction to create an upward flow, allows for the creation of a recirculation of the solid waste, increasing the heat transfer surface with the residual steam due to the cascade effect that occurs when the solid waste falls from the top of the vertical auger 5;In this way, all solid waste quickly reaches its treatment temperature, while producing a mechanical effect that breaks down the organic matter without breaking down the heavy impurities; It is therefore important to highlight that, with this system, it is possible to maintain the movement of the solid waste throughout the treatment time and that, in turn, said treatment time can be adjusted according to the specific requirements of each project, with the only variation being the production capacity; In this step, valve 23' (closed state = represented in completely black), the treated solid waste outlet valve 16, and outlet 16' are kept closed; and the steam inlet valve 22' is open (open state = represented with a white background). The gearmotor 15 is stopped; and the inlet valve 17 and inlet 17' are closed.

[0086] Step 4: (FIG. 8) compensate the pressure with the autoclave assembly T which, at this moment, would be in “Step 1” with a new batch of solid waste loaded and at atmospheric pressure. The operation of the vertical auger 5, by means of the actuation of the gearmotor 8, of the autoclave assembly 1, with the motor turning to the right for upward flow, allows a recirculation of the solid waste to be created, increasing the flashing (release of vapor from a superheated wet liquid or solid when the pressure of the process atmosphere in which it is located is reduced) due to the cascade effect that occurs when the solid waste falls from the top of the vertical auger 5.In this way, due to the pressure difference, a flow of residual steam is created from the autoclave assembly 1' to the autoclave assembly 1, ultimately almost completely depressurizing the autoclave assembly T, while in the autoclave assembly 1, practically all the steam is used to preheat the solid waste recently fed in step 1; in this step, valve 22' ("closed" state = represented in completely black), the treated solid waste outlet valve 16, the treated solid waste outlet 16', the solid waste inlet valve 17, and the solid waste inlet 17' remain closed. The steam outlet valve 23' ("open" state = represented with a white background) is open. The gearmotor 15 is stopped.

[0087] Step 5: (FIG. 9) Depressurize the autoclave assembly 1 which, after the previous step (Step 4), was slightly pressurized mainly due to the presence of non-condensables that need to be removed by means of a vacuum system specifically designed for this purpose. The operation of the vertical auger 5 inside the autoclave assembly 1, by means of the actuation of the gearmotor 8, with the motor turning in the appropriate direction to create an upward flow, allows a recirculation of the solid waste to be created, increasing the flashing due to the cascade effect that occurs when the material falls from the top of the auger.In this way, the pressure difference creates a mixed flow of non-condensables and residual steam toward the vacuum system, which allows the autoclave assembly to be completely depressurized to atmospheric pressure. During this step, valve 22', the treated solid waste outlet valve 16, and the treated solid waste outlet valve 16' remain closed. The steam outlet valve 23' is open. The gearmotor 15 is stopped. The solid waste inlet valve 17 and the solid waste inlet valve 17' are closed.

[0088] Step 6: (FIG. 10) Discharge the batch of treated solid waste towards the discharge conveyor (not shown) which would be just below the treated solid waste outlet 16'. Unlike all the previous steps, in this step the vertical auger 5 of the autoclave assembly is rotated, by means of the actuation of the gearmotor 8, in the opposite direction to create a downward flow of the treated solid waste towards the treated solid waste outlet 16' located below the first common solid waste inlet / outlet area 4. In this step, the valves 22' and 23' (“closed” state = represented in completely black) are closed. The treated solid waste outlet valve 16 and the treated solid waste outlet 16' are open (“on” state = represented with a white background). The gearmotor 15 is stopped. The solid waste inlet valve 17 and the solid waste inlet 17' are closed.

Claims

CLAIMS 1.- An autoclave assembly for the treatment of solid waste by thermal hydrolysis, the autoclave assembly (1, 1') comprising: a vertical container (3), with a lower part (3") in an inverted truncated cone shape, which is configured to house a solid waste (20) under pressure; where the vertical container (3) comprises: o a first common solid waste inlet / outlet area (4) located in the lower part of the vertical container (3), below the lower part (3") of the vertical container (3); o a lower treated solid waste discharge area (16'); o a steam inlet (10') and a steam outlet (10") located in the upper part of the vertical container (3), configured to pressurize and depressurize the vertical container (3) with pressurized steam from a thermal hydrolysis process;a first horizontal conveyor (12,14,15) comprising a valve (17) for controlling the inlet of solid waste and a horizontal auger (13) which conveys solid waste (20) from the solid waste inlet of the first horizontal conveyor (12) to the solid waste inlet / outlet (4) of the vertical container; a second vertical conveyor (5,7,8) comprising a vertical auger (5) inside the vertical container (3) configured to transport the solid waste (20) by means of a downward flow and an upward flow; where the downward flow discharges the solid waste;where the vertical auger (5) has an axis and helical blades (5') along the entire axis, where the helical blades (5') have a diameter smaller than the diameter of the vertical container (3) and comprises, at the height of the lower part in an inverted truncated cone shape (3"), sweeping blades (6) whose diameter extends to the inner perimeter of the vertical container (3) without contact with it in such a way that they allow the solid waste stored in the vertical container to be mobilized so that, depending on the direction of rotation of the gear motor to which the vertical auger is attached, a rotation of the vertical auger (5) that causes a downward flow allows the treated solid waste (21) to be discharged, while a rotation of the auger that causes an upward flow allows an internal feeding and recirculation of the solid waste (20) facilitating its treatment by falling by gravity from the upper end of the vertical auger (3); disintegrating in the form of “rain” or “waterfall”, increasing the contact surface with the process steam. 2.- An autoclave assembly according to claim 1, wherein the helical blades (5') of the vertical auger (5) comprise a helical rim (5”) around the perimeter. 3.- An autoclave assembly according to claim 1, wherein the autoclave assembly (1,1') additionally comprises at least one blade (9) arranged on the inner surface of the upper end of the vertical container (3). 4.- An autoclave assembly according to claim 1, wherein the first horizontal conveyor and the second vertical conveyor comprise two motors (8, 15) supported by two drive frames (7, 14), where the respective motors (8, 15) are connected to the horizontal auger (13) and the vertical auger (5), respectively, thereby causing the rotational movement of the horizontal auger (13) in the feed rotation direction and of the vertical auger (5) in both rotation directions. 5.- An autoclave assembly according to claim 4, wherein the vertical auger (5) has a low rotation speed, preferably between 5 and 30 rpm. 6.- An autoclave assembly according to claim 1, wherein the steam outlet (10”) of the vertical container (3) is connected to a vacuum system (19) configured to depressurize the autoclave assembly (1, T) before opening it to the atmosphere, for feeding or discharging treated solid waste (21). 7.- An autoclave assembly according to claim 1, wherein the steam inlet (10') of the vertical vessel (3) is connected to a steam generator (18) that produces pressurized steam. 8.- An autoclave assembly according to any one of the preceding claims, wherein the vapor inlet (10') and outlet (10") are made through the same connection to the vertical container with the interposition of a self-cleaning filter (10). 9.- An autoclave assembly according to claim 1, wherein the vertical container (3), above (3') the lower part (3") of the vertical container (3), has a selected shape between cylindrical and truncated-conical. 10.- An autoclave assembly according to claim 1, wherein the solid waste inlet / outlet (4) of the vertical container has stops (4') that guide the vertical auger (5). 11.- An autoclave assembly according to claim 1, wherein the vertical container (3) additionally comprises an auxiliary feed inlet (11) at the top of the vertical container (3). 12.- A solid waste treatment system by thermal hydrolysis comprising at least a first autoclave assembly (1) and a second autoclave assembly (1 '), both autoclave assemblies as defined in any one of claims 1 to 11; wherein the steam inlet / outlet (10") of the vertical container (3) of the first autoclave is connected to the steam inlet / outlet (10") of the vertical container (3) of the second autoclave (T) and to the vacuum system (19) by means of valves (23', 23"), one for each steam inlet / outlet and a third (23) before the vacuum system (19), such that the pressurized steam from one autoclave assembly, due to pressure differences, is transferred to the other autoclave assembly, where it condenses by releasing its energy to preheat a solid waste.

13. A method for treating solid waste by thermal hydrolysis, employing the thermal hydrolysis solid waste treatment system of claim 12, the method comprising the following steps of predetermined duration: a) loading a new batch of solid waste (20) into the first autoclave assembly (1) through the solid waste inlet (17) of the first horizontal conveyor (12) and operating the horizontal auger (13) and the vertical auger (5) until the solid waste (20) preferably and at most reaches between 70% and 90% of the volume of the vertical container (3); b) compensating the pressure in the first autoclave assembly (1) with a second autoclave assembly (1') located in step d); for which: communicate both autoclave sets (1, 1') by opening the inlet / outlet valves (23', 23"), keeping the vertical auger (5) rotating in the appropriate direction of rotation create an upward flow for the recirculation of the solid waste (20); c) pressurize the first autoclave assembly (1) to the treatment pressure by injecting steam from the steam generator (18), which entails; in a first sub-stage, pressurize the first autoclave assembly (1) and heat the solid waste (20) to the temperature corresponding to the saturated steam pressure; in a second sub-stage of this step “c)” the conditions are maintained to give the predefined residence time; d) compensate the pressure with the second autoclave assembly (T) which, at this time, would be in step “a)” with a new batch of solid waste loaded and at atmospheric pressure; e) depressurize the autoclave assembly (1); f) discharge the treated solid waste (21). 14.- A method of treating solid waste by thermal hydrolysis, according to claim 13, characterized in that step "a)" additionally comprises extracting the gas contained in the autoclave assembly by means of aspiration through the vacuum system.

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