RO122843B1 - Process and plant for recycling organic waste - Google Patents

Abstract

The invention relates to a process and a plant for recycling organic waste, such as domestic, sanitary, industrial or petroleum waste. The process consists in generating a medium-frequency field acting upon waste in a reactor by creating a temperature ranging between 400 and 900 A C, depending on the waste nature, for 60...90 min, which, due to the temperature value correlated with the waste nature, leads to reactions of pyrogenation, cracking of volatile products and purification of gases, resulting in waste dehydration, liquid fractions volatilization and solid fractions coalification, which leads to the decomposition of the complex compounds into fuel gases, and tars and active carbon being obtained from said combustion; in another stage, due to a temperature ranging between 1250 and 1300A C achieved in another enclosure, the previously obtained tars are decomposed into the same primary compounds, the next stage taking place in a cooler where gases are cooled down to almost the ambient temperature, then they pass through a bed of lime granules and a bed of active carbon, respectively, the solid particles still contained by the gases being retained by some molecular sieves and the resulting gases being then discharged into the atmosphere. The claimed plant consists of a general electric board (A) in connection with a primary reactor (B) connected to a secondary reactor (C) followed by a cooler (D), an absorber (E) consisting of an element that contains a bed of lime granules and an element that contains a bed of active carbon, some sieves (52 and 53) being placed between the two said elements in order to retain the solid particles.

Description

The invention relates to a process and an installation for the recycling of organic waste by means of heat treatment, intended for the recycling of household, sanitary, industrial, petroleum waste.

in the field of waste recycling is known an installation produced by the Italian company Pirelli Ambiente, which produces waste electricity through a technology called RDF (Refuse Derived Fuel), producing a fuel based on waste, which comes entirely from the dry side of urban waste, combined with calorie-rich components, such as chlorine-free plastic or granulated rubber.

This well-known facility has the disadvantage that it has to use to produce high-calorie fuel-rich components.

It is known that at present, the waste resulting from the meat processing industry, respectively in slaughterhouses, butchers, restaurants from remote locations such as cottages, motels, hotels, holiday homes, individual households in the outskirts are collected, transported and stored at the pits. ecological waste or destroyed by incineration. The disadvantage of the organic waste pits is that, once filled, these pits must be covered and closed, requiring another space. Another disadvantage of incineration combustion is that toxic fumes are released and incineration combustion is uncontrolled.

Another relevant document of the prior art, identified from the documentary research, is US patent 4831944, which presents a process and device for the destruction of solid elements by pyrolysis, in which a column made of such solid elements is pointed upwards and is crossed. by a string of hot gases penetrating that column, the string of hot gases being generated by a plasma jet. The results of the invention are the destruction of non-combustion residues and the improvement of the process of dispersing the molten residues.

The technical problem that the invention solves is the creation of a recycling plant for organic waste by heat treatment and in the absence of air.

The process of recycling organic waste consists of the following operations:

- the waste is introduced into the reactor;

- depending on their nature, the waste is subjected to temperatures between 400 and 900 ° C, and the exposure time is between 60 and 90 min;

- due to the high temperatures, pyrogenation and cracking reactions are carried out, resulting in tar and combustible gases, such as hydrogen, methane, carbon oxides, gaseous hydrocarbons, nitrogen;

- by subjecting to temperatures between 1250 and 1300 ° C, the components in the form of tar are broken down into primary components;

- the gases resulting from the aforementioned operations are cooled to a temperature between 25 and 30 ° C, by contact with a cold wall;

- the cooled gas then passes through a layer of lime granules that retain the sulfur compounds;

- gases lacking sulfur compounds then pass through a layer of activated carbon, which retains carbon dioxide;

- the solid particles that the gases still contain are retained by some sites with dimensions of 0.3 mm and 1 mm;

As an example: of the sulfur combinations we have: CaS + CO ₂ + H _Z O - CaCO ₃ + H ₂ S, and lime decomposes into calcium carbonate: CaCO ₃ -CaO + CO ₂ , and calcium sulphide is decomposed by CO ₂ , forming H ₂ S, and H ₂ S + V ₂ O ₂ -H _Z O + S clean; CO ₂ is retained by activated carbon, while CO is non-toxic.

The organic waste recycling plant consists of a general electrical panel (A), connected to a primary reactor (B), connected to a secondary reactor (C), followed by a cooler (D), an absorber (E) consisting of an element containing a layer of lime (44) and an element containing a layer of activated carbon (45), between the two elements being interspersed some sites (52, 53) for retaining solid particles, and the painting general electrical

EN 122843 Β1 (A) is composed of a static power converter (5) powered by a switch (3), 1 of some voltage feeders (6,9 and 11 respectively) which supply pulse generators (7, 8 and 10 respectively, the static power converter (5) voltage supplying a 3 coil L of an inductor (15), which is provided with a capacitor battery (2) electrically connected in parallel with the coil L, and an induced one ( 14) is provided with a movable basket (28) 5 for waste, as well as a folding lid (23). The secondary reactor (C) is provided with an induction coil (38) electrically connected in parallel with a battery of 7 capacitors similar to that of the inductor in the primary reactor (B) and positioned in the same general electrical panel (A). The cooler (D) is provided with a 9-cooling jacket (56) supplied with water in the closed circuit, and a purge connection (57) is positioned underneath the active carbon element (45) of the absorber (E). 11

Advantages of this installation:

- being an anaerobic combustion, no smoke is produced; 13

- the possibility of dioxin is greatly reduced (dioxin designates a group of about 200 polychlorinated dibenzo-p (RCDD) and dibenzofuram (PCDF) compounds, 15 where different compounds are formed in the combination of carbon dioxide and chlorine at high temperatures, in especially in the case of fires;

- the energy consumption in this case is half of the energy consumption of a resistive heating; 19

- the fuel gases have a calorific value of 4000 kcal / Nm3;

An example of embodiment of the invention is given below, in connection with FIG. from 21 1 ... 6, which represents:

FIG. 1, a vertical section through the organic waste recycling plant, according to the 23 invention;

FIG. 2, the electronic scheme for medium-frequency induction electric heating 25;

FIG. 3, the electrical diagram of the capacitor battery as detailed in the diagram of fig. 2; 27

FIG. 4, vertical section through the primary reactor B of the installation, according to the invention;

FIG. 5, detail regarding the hinge of the primary reactor sealing lid B.29

FIG. 6, axial section through the cover of the primary reactor B.

The process of recycling organic waste according to the invention consists of 31 following operations:

- recycle waste is introduced into the reactor, 33

- the coil of the inductor is supplied with electrical energy, causing the generation of a medium frequency induction field in the indus, which acts on the waste. 35 The temperature at which the waste is subjected is between 400 and 900 ° C, depending on the nature of the waste. The time of this operation is between 60 and 90 min; 37

- due to the temperature correlated with the nature of the waste there are reactions of pyrogenization, cracking of volatile products and purification of gases. Thus, firstly, dehydration of waste occurs first, then volatilization of liquid fractions and carbonization of solid fractions takes place. As a result, the complex compounds are broken down into combustible gases 41 such as hydrogen, methane, carbon oxides, gaseous hydrocarbons, nitrogen, and water vapor; next to these, as a result of this combustion, tar and activated carbon are obtained; 43

- in another phase, due to a temperature between 1250 and 1300'C, produced in another enclosure, the decomposition of the tar obtained from the previous operation takes place, 45 which leads to the same primary compounds;

- the next operation which takes place in a cooler, at a temperature between 25 47 and 30 'C, the gases obtained from the previous operations are cooled close to the ambient temperature; 49

RO 122843 Β1

- the chilled gases pass through a layer of lime granules, which have the role of retaining sulfur compounds from the gases;

- In another operation, which occurs due to the passage of gas through an active carbon layer, carbon dioxide is retained;

- the solid particles that the gases still contain are retained by some meshes with dimensions of 0.3 mm and 1 mm.

Following the process described above, the gases resulting from the recycling of waste are released into the atmosphere without life-threatening compounds, without carbon dioxide and also without solid particles.

The organic waste recycling plant according to the invention is composed of a general electrical panel A, a primary reactor B, a cracking plant C, a gas cooling installation D and an absorption plant E. The primary reactor B, which uses medium-frequency induction electric heating, it consists of a working frequency power supply, a battery with power factor 2 compensating capacitors, an induced and a heating inductor F, and an inductive installation control and control block 4.

Power supply 1 is a static power converter, powered by the low voltage network (380Vac), and the variable working frequency can be tuned to the proper frequency of the resonant circuit, consisting of the heating inductor and inductor F and the compensating battery of the power factor. power 2.

From the general electrical panel A the entire operation of the complex installation can be supervised.

The table contains the commands of:

- starting and stopping the installation also allowing;

- reading the output voltage (at the inductor terminals);

- reading of current in load (through inductor);

- reading the temperature in the indus (any exceeding the temperature set as the limit of operation in the indus, automatically stops the operation of the system, until the temperature returns to normal).

The power supply 1 consists of a static power converter 5 and a control and control block 4.

The static power converter 5 comprises a fully ordered rectifier consisting of six semiconductor power devices (T1, .., T6), a filter coil L1 connected to the rectifier, a single phase inverter consisting of four semiconductor power devices (T7 .. .T10).

The rectifier and coil L1 form for the inverter a constant source of direct current.

The control and control block 4 contains the power supplies 6.9 and 11 and the pulse generators 7, 8 and 10.

The coil L of the inductor F is compensated in parallel by the capacitor battery 2.

For the manual tuning of the capacitors' power to the variable power factor of the induction heating system, it is necessary to divide the tuning battery into a fixed part and an adjustable one by manual switches: the capacitor from the fixed tuning battery 12, the capacitors from the adjustable tuning battery C1, C2, C313 and manual switches K1, K2, K3.

The main components of the primary reactor B are the inductor and the inductor F, with the following important milestones: - the inductor 14 made of cast iron or refractory steel, a thermal insulation 16 covering the inductor, the inductor 15 of the copper pipe, rods of pertinax 170,

EN 122843 Β1 which is mounted to maintain the winding pitch of the inductor, thermal insulation 18, 1 cylindrical piece of iron 21, welded to the inductance on the exhaust gas outlet, upper iron flange 23, fixed to the induced by threading, a gasket 24, a sealing cap 3 of the iron casing 22, which is fastened to the upper flange 23 by an iron hinge

26, having the following parts: hinge shaft 30, fuse 31, hinge body 32 welded to upper flange 5, hinge body 33 welded to lid, then sheath temperature transducer 25, of iron, fastened by welding of cap at the base of the hole through which the temperature transducer in the sheath, 7 the lower plate of the indus 27, made of the same material as the cylindrical body of the indus and welded to the base of the indus on all its circumference, gas exhaust pipe 9 19, which is fixed by threading of the piece 21, screw clamping 20 between lid 22 and upper flange 23, waste basket 28. The flange system, gasket, lid ensures sealing 11 of the casing. The entire inductor-inductor system is fixed to a base 29. The hinge 26 is welded to the upper flange 23 and to the sealing cover 22. In operation, the cover 22 of 13 of the primary reactor B is fixed to the upper flange 23 by a screw 34, for more safety. 15

The primary purpose of the primary reactor B is mass heating for volume heat treatment of waste. 17

The working frequency of the installation is adjustable between 8000 and 9000 Hz.

Through the inductor, water is recirculated at a speed of 2 m / s, using a minipump 19 of water, to cool it. The water is brought to the copper pipe of the inductor through a rubber hose and also discharged through a rubber hose. At the inlet and outlet ports of the water in the copper tube of the inductor coil, an electrical connection system is provided for the electrical supply of the coil from the output of the single-phase inverter from the 23 power converter.

The gas exits through the elbow-shaped pipe 50, connected to the flange 49, and 25 are introduced into the cracking installation C, whose components are the inductor 38 and thermally insulated and the inductor 39 made from the copper pipe through which cooling water flows. recirculated 27 with a minipump, a pipe which is cemented in a refractory paste and which, by solidification, provides thermal insulation and gives mechanical strength to the coil, and 40 and 41 are 29 connecting flanges.

The power supply of the cracking system is made from the general electrical panel A 31 from the low voltage network (380 VAC) all at the inlets and outlets of cooling water and also through an electrical connection system from the static power converter. . The casing 33 of the cracking plant is filled with iron balls 37, which have the role of maintaining the high temperature between 1250 and 1300'C, temperature ensured by the induction of medium frequency 35 for the cracking of volatiles, by the static converter of its own power, which it has the same electrical pattern and works at a frequency between 8000 and 9000 ° C. 37

From the cracking plant C the gases are introduced into the cooling system D through the flange and exits through the flange 43. 39

The gas circulation is made from the bottom up, the gases being cooled to a temperature between 25 and 30 ° C. 41

From the cooling system D the gases are introduced into the absorption system E, whose main elements are two compartments, one filled with lime granules 44 and another 43 filled with activated carbon granules 45.

To use the system, proceed as follows: open the lid 22 45 and insert it into the basket 28 inside the primary reactor B, the organic waste for recycling, close the lid 22 and start the installation by connecting to the electrical panel 47 general A, in this way the voltage supplying the coil of the inductor B. is coupled.

EN 122843 Β1 a medium frequency induction field is produced, which leads to the heating of the inducer chamber in the primary reactor B in which the waste is located, the heating of the inducer chamber from the primary reactor can be done at temperatures between 400 and 900 ° C, and, Depending on the type of waste, their destruction begins with household waste that requires lower temperatures and ends with synthetic or high density waste whose destruction requires higher temperatures. The time of exposure of the waste to the temperature is between 60 and 90 minutes and due to the high temperatures there are reactions of pyrogenization and cracking which result in tar and combustible gases.

The gases resulting from the anaerobic combustion of waste from the primary reactor B reach the cracking plant C, where due to the medium frequency field generated by the coil 39 of the secondary reactor, it is heated to temperatures between 1250 and 1300 ° C. At these temperatures, gases from the primary reactor B are broken down into primary compounds such as, for example, hydrogen, methane, carbon oxides, gaseous hydrocarbons, nitrogen, water vapor.

This phase aims to reduce the toxicity of the gases from the first combustion and their conversion into combustible gases.

The gases thus obtained go through the cooling system C, where, due to a water cooling jacket, their temperature is brought up to values between 25 and 30 ° C.

The cooled gases then pass through the sieves 46 and 47 where large particles of tar are retained, then through the column with lime granules 44 the sulfur compounds are retained. Next the decomposed combustion gases, filtered and devoid of sulfur compounds, go through column 45, which contains activated carbon granules, whose role is to retain the carbon dioxide from them.

In this way, the gases released into the atmosphere do not contain carbon dioxide, sulfur compounds and only a gaseous mixture that can be used as liquefiable fuel.

It is desirable that the installation according to the invention be provided at the base of column 45 with activated carbon, with a connection (not shown), through which steam is introduced at temperatures between 200 and 300 ° C and at a pressure of 1 -2 atm. , thus purging the residues and the chemical compounds retained by the activated carbon granules.

This purge is signaled by odorous emission and needs to be done so that the gas emission is as little harmful (it can be deodorized and odorless).

When the flue gas emission has stopped, the voltage from the general electrical panel A is switched off, the primary reactor cover B is opened, allowed to cool and then emptied the contents of the flask 28.

The operating cycle of the installation can then be resumed.

As can be deduced from the above information, the installation according to the invention can be powered and supervised by a single person without too high a qualification.

Claims (7)

1. Process for the recycling of organic waste, characterized in that it is 3 consisting of the following operations: - introduction of waste into the reactor, 5 - heating of waste at temperatures between 400 and 900 ° C, exposure time between 60 and 90 min, depending on their nature, 7 - pyrogenization and cracking reactions resulting in tar and combustible gases, such as hydrogen, methane, carbon oxides, gaseous hydrocarbons, nitrogen, 9 due to high temperatures; - decomposition of tar into primary components by subjecting them to 11 temperatures between 1250 and 1300'C; - cooling gases resulting from the above operations at a temperature between 25 and 13 30 ° C by contact with a cold wall; - passage of cooled gas through a layer of lime granules that retain sulfur compounds; 15 - passage of gases lacking sulfur compounds through a layer of activated carbon that retains carbon dioxide; 17 - Removal of solid particles from gases by passing them through sieves with dimensions of 0.3 mm and 1 mm. 19 2. Organic waste recycling plant, characterized by a general electrical panel (A), connected to a primary reactor (B), connected 21 to a secondary reactor (C), followed by a cooler ( D), by an absorber (E) consisting of an element containing a layer of lime (44) and of an element containing a layer of activated carbon 23 (45), between the two elements being interspersed some sites (46) , 47) for the retention of solid particles. 25 3. Organic waste recycling plant according to claim 2, characterized in that the general electrical panel (A) is composed of a static power converter 27 (5) powered by a switch (3), of some voltage feeders. (6.8 and 11 respectively) which supply pulse generators (7, 9 and 10 respectively), and a static power converter 29 (5) is powered by a coil (2) of an inductor (B). 4. An organic waste recycling plant according to claim 2, characterized in that an inductor (B) is provided with a capacitor battery (2) electrically connected in parallel with the coil of an inductor (B), and the inducer also has a folding lid (23) watertight, 33 and inside, a movable basket (28) for waste. 5. An organic waste recycling plant according to claim 2, characterized in that a secondary reactor (C) is provided with an induction coil (38), electrically connected in parallel with a capacitor battery similar to the inductor of a 37. primary reactor (B) and positioned inside a general electrical panel (A). 6. An organic waste recycling plant according to claim 2, characterized in that a cooler (D) is provided with a cooling jacket (56), supplied with water in the closed circuit. 41 An organic waste recycling plant according to claim 2, characterized in that it is provided with a purge connection (57) positioned underneath the activated carbon element 43 (45) of an absorber (E).