RU167118U1 - DEVICE FOR THERMAL DESTRUCTION OF POLYETHYLENE AND POLYPROPYLENE WASTE - Google Patents

Abstract

1. Device for thermal destruction of waste polyethylene and polypropylene, including a reactor for thermal destruction of polymer raw materials with devices for loading raw materials and unloading coke, a fractionation unit for the destruction of polymer raw materials, a heat exchanger unit, equipment for thermal catalysis, and a feed unit with pipelines for refrigerant circulation in the form of water, characterized in that the device comprises at least two thermal decomposition reactors, which are connected in parallel with by a complete technological cycle: heating - thermal destruction - cooling - coke unloading - loading of raw materials; in addition, each of the reactors is equipped with a mobile or removable furnace, which is configured to be disconnected from the first reactor and connected to the second reactor, and the fractionation unit for the degradation products of the polymer feedstock, namely the vapor-gas mixture, consists of a water-cooled heat exchanger connected in series, in which scheme of countercurrent motion of phases with a downward flow of a vapor-gas mixture of hydrocarbons, a collection tank of hydrocarbons with a boiler, a dewaxing unit consisting of a nozzle the lower part and the reflux condenser installed in the upper part and made in the form of a shell-and-tube heat exchanger, a distillation column for separating fractions of diesel fuel and gasoline, consisting of a packed lower part and a reflux condenser installed in the upper part and made in the form of a shell-and-tube heat exchanger, and a boiler installed in cube columns, tubular vertically mounted heat exchanger with

Description

The field of technology.

The utility model relates to the disposal of industrial and household waste from plastics, in particular from polyethylene (hereinafter - PE) and polypropylene (hereinafter - PP), and in particular, to technical means for thermal and thermocatalytic destruction of these wastes in a batch or continuous mode, to receive after their utilization and processing of motor fuels (gasoline, diesel fuel), heating oil, hydrocarbon gas and carbon residue (coke).

The level of technology.

One of the most important problems that the world community is facing at present is the problem of environmental pollution by the waste of polymer materials, in particular, plastics based on PE and PP.

Until recently, the main methods for the disposal of such wastes were their storage at landfills of solid household waste (MSW) or simple incineration. Those. conventional waste treatment involves incineration or landfill without initial sorting and separate treatment depending on the types of waste disposed. Such waste disposal certainly pollutes the environment.

Among the types of waste, it is plastic waste that becomes the main means of pollution due to its natural diversity and gradual accumulation. The traditional disposal of plastic waste involves calcining, or, otherwise, sorting for recovery. In this case, the calcination process (method) consists in the direct burning of plastic waste, while the sorting process (method) for subsequent recovery involves sorting plastic waste and recovering recycled plastic.

The first method (calcination) refers exclusively to engineering consumption, which requires expensive equipment to prevent the creation of secondary sources of environmental hazards, such as air pollution. At the same time, the recovery method has a problem in the complexity of processing due to the wide variety of types of recyclable plastic and the additives it contains. Also, the reduced physical and mechanical characteristics of recycled and recovered products often make the recovery process impractical.

At the same time, the above methods do not solve the problem of environmental pollution, since in the case of waste disposal at landfills (during landfill) for most polymeric materials there simply are no microorganisms capable of converting (processing) them into environmentally friendly substances. And when burned, a significant amount of gaseous and solid waste is generated, which, in turn, must also be disposed of.

A number of recycling methods for PE and PP are known. Most of these methods use various methods and devices for recycling plastic waste products. The main disadvantage of these methods is that the mechanical properties of products from recycled plastics deteriorate by 15-20% compared with the original products [Klinkov AS, Belyaev PS, Sokolov MV Utilization and recycling of polymeric materials: textbook. allowance. - Tambov: Publishing house of Tamb. state tech. University, 2005. - 80 p.].

Among the known technologies, pyrolysis, a method of controlled thermal decomposition of the feedstock without oxygen, should be highlighted. As a result of the pyrolysis processing of raw materials, air-conditioned products are obtained: boiler (furnace) fuel (used for its intended purpose and to obtain components of the diesel (gasoline) fraction in the presence of a distillation column); pyrolysis gas (used as fuel for the installation); dry carbon residue of the 4th hazard class (used for local, construction and remediation needs, and also introduced as a filler in concrete mixtures); heat generated during processing (used for space heating).

Pyrolysis is a set of elementary reactions of decomposition (destruction) of organic matter into products with a lower molecular weight. Reactions proceed both sequentially and in parallel, and at the same time are inextricably linked.

Today, there are a number of classifications of pyrolysis, namely:

dry pyrolysis (without oxygen access) and oxidative pyrolysis (in case of partial burning of waste or as a result of direct treatment of waste with hot flue gases);

low temperature pyrolysis (300-550 ° C), aimed primarily at obtaining products of the liquid fraction;

medium temperature pyrolysis (550-800 ° C), aimed at obtaining products of all fractions;

high temperature pyrolysis (over 900 ° C), aimed at obtaining gaseous products of the process;

pyrolysis, implemented in installations of cyclic (periodic) and continuous operation.

However, in the CIS countries, including Russia and Ukraine, the waste recycling method by pyrolysis has not yet become widespread. The reason for this is, firstly, the difficulty in operating the technologies and equipment on the market of the CIS countries, secondly, the lack of experience with local manufacturers that do not guarantee the operation of plants, and thirdly, the lack of effective pyrolysis technologies and devices that implement these technologies. As a result, the high cost of foreign analogues.

A known method of recycling PE [Method of recycling secondary polyethylene, patent for invention RU 2106365, IPC C08J 11/04, application No. 93011365/04 of 03.25.1993, publ. 03/10/1998], according to which pre-crushed PE is subjected to fractionation in a boiling solvent into a soluble sol fraction and an insoluble gel fraction with separation and washing of fractionation products, and then low-temperature pyrolysis in vacuum is carried out separately for each fraction.

The main disadvantage of this method is the use of toxic solvents in the recycling technology, as well as the multi-stage recycling process.

Known methods for processing waste polymeric materials into valuable organic substances. One of these methods is the thermal and thermocatalytic destruction of polymer wastes into carbon fractions, which, after appropriate treatment, can be used as high-quality motor fuel [http://i-pec.ru/wp-content/uploads/2014/01/Thermal- destruction-waste-pyrolysis.pdf].

There are a number of known methods for processing waste thermoplastics, which are implemented using appropriate plants, which, therefore, are part of these methods. So, for example, there is a known method for processing waste thermoplastics and an installation for its implementation, according to which pyrolysis is carried out in a reactor at a temperature of 480-600 ° C and a pressure of 0.1-0.15 MPa, and the liquid phase is separated from the gas-vapor mixture by air condensation in two steps. In the first stage, the gas-vapor mixture is cooled at temperatures from 280-320 ° C at the beginning of condensation and up to 110-120 ° C at the end of the condensation, followed by the release of high-boiling components of liquid fuel and paraffins, and in the second stage, the gas-vapor mixture is cooled to a temperature of 50- 60 ° C followed by the release of low-boiling liquid fuel components. The installation is equipped with a feeder for continuous feed [Pat. 2459843 RF, IPC7 C08J 11/04, B29B 17/00, F23G 5/027. A method of processing waste thermoplastics and installation for its implementation / Shapovalov Yu.N., Ulyanov A.N., Andreev V.A., Salikov P.Yu. and etc.; application No.2015151482 / 02; Claim 12/15/2010; Publ. 08/27/2012, Bull. No. 24].

The disadvantage of this installation is the lack of fractionation equipment, which allows to obtain clear fractions of liquid hydrocarbons, such as gasoline, diesel fuel and heating oil.

A known installation of thermal destruction of PP and PE waste, consisting of a thermal destruction reactor, a heating unit, a heat exchanger block and a distillation column, on the basis of which the method of the same name is implemented [Method for thermal destruction of polyethylene and polypropylene waste, utility patent UA 77844, IPC (2013.01) C10G 1/00, C10B 53/00, F22G 5/027, application No. u201210850 of 09/17/2012, publ. 02/25/2013, Bull. No. 4].

A disadvantage of the known installation is its operation in periodic mode, as a result of which heat is consumed for heating equipment after stops for coke unloading and loading of raw materials into the reactor, and the proportion of substandard products formed during plant starts and stops increases. In addition, with such a typical (generally accepted) distillation column design, when all products are produced in one column in one pass, and the column is irrigated with a chilled top product (in this case, gasoline), hydrocarbon fractionation from a gas-vapor mixture containing up to 20 % inert hydrocarbon gases, extremely difficult.

A known method and device for processing waste, including waste sorting, separation of light plastic waste and cracking, the gradual cooling of cracking products, the separation of gaseous hydrocarbons and subsequent fractional distillation of liquid hydrocarbons. The apparatus of this invention includes: a garbage cart that carries waste and which is unloaded onto a conveyor belt for transporting waste to a shredder that is equipped with a mill on which the waste is shredded. The above mill can generate a lot of wind power, which can reduce the moisture and earth content of the waste by spraying the waste depending on its specific gravity. The device also includes four cracking furnaces, an annealing furnace, a cooling water pipe, a fuel oil line, an oil gas line, a gas burner and other typical elements [Processes and apparatus for energy recovery through waste sorting and calcination, patent US 005998682 A dated 07/12/1999 , IPC (1999) C01G 1/00, С07С 1/00, application No. 09/182647 of 10.30.1998].

The disadvantage of this method is the used periodic operation scheme of the installation, according to which the cracking furnaces are switched on one by one, passing through the stages of "loading plastic waste - cracking plastic - cooling the cracking furnace - unloading coke", as a result of which there is an increased fuel consumption for the next reheating cooled cracking furnace at the beginning of the next cycle of the installation. In addition, due to the long idle time of the cracking furnaces at the cooling stage (longer than the time of the actual cracking process), in order to create a continuous cycle of the installation operation, it is necessary to implement a scheme with an increased number of cracking furnaces (four), which makes the installation more expensive. The disadvantage is that the hydrocarbons after cracking are cooled, hydrocarbon gas is separated, then reheated to 450 ° C and fractionation of the hydrocarbon mixture is carried out. This leads to a twofold consumption of fuel (for heating) and water (for cooling products). A disadvantage of the invention also lies in the fact that cracking is carried out at an elevated pressure of 0.4 MPa, which significantly increases the cost of the equipment in which the process is carried out.

A device for the pyrolysis of plastic waste containing a heating furnace, a metal retort, a gas burner, a device for continuous loading of raw materials and unloading coke residue, a liquid hydrocarbon condenser [Device for pyrolysis of plastic waste, utility model patent UA 22609, IPC (2007) C10G 9 / 28, F23G 7/00, application No. u 200612719 dated 04.12.2006, publ. 04/25/2007, Bull. No. 5].

The disadvantage of this device is that liquid hydrocarbons are not subjected to fractionation to obtain marketable products, which reduces the economic effect of the operation of this installation.

A known installation for the continuous thermal utilization of organic waste containing a pyrolysis reactor with a heating system, a loading and unloading device, as well as a condensation unit with water cooling [Installation for the continuous thermal utilization of organic waste to produce liquid fuel. Utility Model Patent UA 50431, IPC (2007) C10G 1/00, F23G 5/027, Application No. u 200912544 of December 3, 2009, publ. 06/10/2010, Bull. No. 11].

The disadvantage of this device is that all condensed heavy fractions are returned back to the reactor, where they are again subjected to heating, degradation and re-condensation. This leads to significant fuel costs for heating and increases the flow of refrigerant (water) for cooling. In addition, the device does not allow the separation of diesel and gasoline fractions, as follows from the list of products received: the installation receives only liquid fuel, an analogue of diesel fuel (but in fact it is a mixture of diesel and gasoline fraction).

The closest in technical essence to the invention, which is claimed, is a pyrolysis complex for the disposal of carbon-containing waste, including a pyrolysis reactor for thermochemical decomposition of waste, loading and unloading devices, a unit for separating pyrolysis steam into gaseous and liquid components, a waste heating device in the reactor, and a cleaning system pyrolysis gas for supplying to a gas turbine power plant, a system for purifying gases emitted into the atmosphere, characterized in that the pyrolysis reactor made of two tubular chambers installed one above the other - the upper tubular chamber with perforated holes for collecting and exiting the pyrolysis vapors from the reactor and the lower heat-resistant tubular chamber for heating the waste through metal walls, and to ensure the start-up mode and heating of the waste without air access autonomous chamber for the joint combustion of pyrolysis liquid and pyrolysis gas, from which two heat-resistant pipes emit oxygen-free hot gases for external and internal heating Waste [RU 2434929, IPC (2006.01) S10V 53/02, V09V 3/00, F23G 5/027, publ. 11/27/2011, Bull. No. 33].

The disadvantage of the prototype device is the imperfection of its design, which leads to insufficient efficiency, in particular, to the fact that during periodic operation of the installation it is very difficult to achieve synchronous operation of the distillation column with a pyrolysis furnace, which affects the quality of the finished products - gasoline and diesel fuel.

The utility model is based on the task of improving the design of the installation of thermal and thermocatalytic destruction of plastic waste by developing effective designs of units (apparatuses) of the hydrocarbon fractionation stage, which will allow to obtain high-quality products, namely gasoline and diesel fuel, from a gas-vapor mixture containing up to 20% inert hydrocarbon gases, as well as improving the energy efficiency of the utilization of organic raw materials.

The essence of the invention.

The specified technical problem is solved in that in a device for thermal destruction of waste polyethylene and polypropylene, which includes a reactor for thermal destruction of polymer raw materials with devices for loading raw materials and unloading coke, a fractionation unit for the destruction of polymer raw materials, a heat exchanger unit, equipment for thermal catalysis, and also a supply unit with pipelines for circulating the refrigerant in the form of water, new is that the device contains at least two reactors of thermal dest functions that are connected in parallel with providing a complete technological cycle “heating - thermal destruction - cooling - coke unloading - loading of raw materials”, while each of the reactors is equipped with a mobile or removable furnace, which is configured to disconnect from the first reactor and attach to the second reactor and the fractionation unit of the degradation products of polymer raw materials, namely the gas-vapor mixture, consists of water-cooled heat exchanger connected in series, in which the circuit outward flow of phases with a downward flow of a gas-vapor mixture of hydrocarbons, a collection tank of hydrocarbons with a boiler, a dewaxing apparatus consisting of a packed lower part and a reflux condenser installed in the upper part, and made in the form of a shell-and-tube heat exchanger, a distillation column for separating fractions of diesel fuel and gasoline, consisting from a nozzle bottom and a reflux condenser installed in the upper part and made in the form of a shell-and-tube heat exchanger, and a boiler installed in a column cube a tubular vertically mounted heat exchanger with a downward movement of gasoline and hydrocarbon gas vapors, while the device contains a heterogeneous catalyst in the form of strips of titanium twisted into spirals, each spiral pre-twisted in different directions, forming spirals of left and right rotation, strips of titanium placed in the collection cube, in the tubes of the heat exchanger, in which the high-boiling hydrocarbons from the vapor-gas mixture are condensed, in the tubes of the dewaxing unit and in the tubes of the refluxing unit p rectification columns.

As a heterogeneous catalyst, the device contains a catalyst made in the form of strips of titanium with a width of 5-20 mm, a thickness of 0.5-1.5 mm, which are twisted into a diameter of 10-30 mm, a length of 0.1-1 m, in increments spirals 10-40 mm.

Strips of titanium twisted in a spiral are contained as a mass transfer nozzle in a dewaxing unit and in a distillation column.

The deparaffinizer is made in the form of a column apparatus, the lower part of which is filled with a mass transfer nozzle made in the form of titanium spirals and having a free section of 90-93%.

A shell-and-tube heat exchanger is installed on top of the dewaxing device, which serves as a reflux condenser, and titanium spirals of different directions of rotation are placed in the tubes of the dewaxing device.

These signs make up the essence of the technical solution.

The presence of a causal relationship between the set of essential features of a technical solution and the achieved, technical result is as follows.

The supply of fuel gases with a temperature of 600-900 ° C to the boiler of the hydrocarbon recovery cube (furnace fuel fraction) and distillation column cube allows preheating of the collection cube and distillation column cube to operating temperatures and is faster (by an average of 20-30% ) output of the installation to the scheduled mode.

This significantly (on average by 50-60%) reduces the number of substandard fractional products formed during the start-up period, reduces (on average by 50-60%) the cost of heat and energy for their repeated “dispersal” to obtain conditioned products, and also allows maintain regulatory temperatures at which products are selected, which ultimately improves their final quality.

Maintaining the temperature in the collection cube 300-360 ° C allows you to get heating oil with a flash point of 60-90 ° C, which indicates the absence of light fractions in the collection cube. Condensation of vapors of paraffins in the dewaxing apparatus at a temperature of 180-300 ° C allows to obtain diesel fuel with predetermined properties.

So, at 300 ° С diesel fuel is obtained as “summer” grade, i.e. with a freezing temperature of 0 ° C, and at a temperature of 180 ° C, diesel fuel of the winter grade is obtained with a freezing temperature of minus 35 ° C.

In addition, with this temperature range (180-300 ° C), the amount of diesel fuel taken can be controlled by removing or adding paraffins from / to it.

Maintaining a temperature in the cube of the distillation column of 160-220 ° C allows you to adjust the content of light fractions, achieving a regulated value of the flash point of diesel fuel 40-62 ° C.

Maintaining the temperature in the upper part of the distillation column 35-100 ° C allows you to get gasoline with a given fractional composition and a final boiling point of not higher than 215 ° C, which corresponds to accepted standards.

Maintaining the temperature of gasoline after condensation in the heat exchanger at the level of 20-35 ° C allows to reduce by 2-3% the loss of vapor of gasoline with hydrocarbon gas, which leaves the heat exchanger with gasoline.

In the table. 1 presents data on the quality of gasoline obtained by the method implemented on this device.

As can be seen from the table. 1 data, the properties of gasoline obtained by the method implemented on this device comply with the standards.

Table 2 shows data on the quality of diesel fuel obtained by the method implemented on this device.

As can be seen from the table. 2 data, the properties of diesel fuel obtained by the method implemented on this device comply with the standards.

The operation of the installation in a periodic (sequential) mode with at least two thermal destruction reactors, which are included in series operation, allows for continuous operation of the fractionation unit.

This makes it possible to stabilize the temperature of flues, pipelines and equipment of the fractionation unit throughout the entire fractionation period.

Compared to well-known technical solutions in which the fractionation unit operates intermittently (periodically), this leads to savings in heat and energy that are wasted during repeated starts and plant stops, and the quality of the finished products at the outlet is also improved.

In this case, fuel economy is obtained by reheating the furnace, as if it was cooling along with the reactor. Due to this, the lining of the furnace is not subjected to large temperature differences, which usually occurs when cooling, and also increases the life of the lining.

After disconnecting the furnace from the reactor, the latter is put into cooling mode and can be cooled by the air supplied from the burner blower.

Due to the fact that the thermal destruction reactor is cooled without a furnace, which has a large lining mass, the time of the cooling process to a temperature of 50 ° C, at which you can open the hatch and unload the coke, is reduced by 2-2.5 times.

As shown by the results of experimental studies, cooling a gas-vapor mixture to 300-360 ° C in a tubular heat exchanger, which is installed vertically, in which a gas-vapor mixture with condensed heavy hydrocarbons moves in a downward flow through tubes in which titanium spirals are placed with both unidirectional and different direction of rotation, is the most effective version of the hardware design of this process (condensation of heavy hydrocarbons) against the background of a high concentration of hydrocarbon ha per in mixture and low partial pressure of hydrocarbons.

The helical surface of the spiral not only increases the contact area of the phases, but also due to the fact that the spirals have a helical surface of different directions of rotation (left and right) on one vertical branch, it increases the mixing intensity of the vapor-gas mixture due to a change in the direction of rotation during its movement through the tubes in which spirals are installed.

This, in turn, increases the efficiency of heat and mass transfer by 2-2.5 times, and the specific contact surface of the phases increases by 1.5-2 times.

The hydrocarbon cube collector is made in the form of a cylindrical container located horizontally.

It was experimentally established that the capacity of the hydrocarbon cube collection tank should be selected from the condition that the residence time of the heating oil (mixture of carbohydrates) in it was sufficient to evaporate light fractions.

In this case, to work in periodic mode, the volume of the cube-hydrocarbon collector is determined by the formula

V _p = 2N _c · Q _p ,

where Q _p - installation productivity of heating oil for one cycle of operation, m ³ / cycle;

N _c - the number of cycles in periodic mode;

V _p - the volume of the cube-collection of hydrocarbons, m ³ .

For continuous operation, the volume of the hydrocarbon cube collector is determined by the formula:

V _n = 2t · Q _n ,

where Q _n - installation productivity of heating oil in one hour, m ³ / hour;

t is the number of hours of continuous operation, hours;

V _n - the volume of the cube-collection of hydrocarbons, m ³ .

The hydrocarbon collection cube is equipped with a boiler, which is heated by fuel gas. This allows you to get the product in the form of heating oil that meets the standards.

The deparaffinizer is made in the form of a column apparatus, the lower part of which is filled with a mass transfer nozzle made in the form of titanium spirals loaded into bulk (irregular nozzle) with a spiral length of 0.1-0.2 m, or in the form of spirals assembled in cassettes (regular nozzle ) with a spiral length of up to 1 m, having a free section of 90-93%.

At the top of the dewaxing unit, a shell-and-tube heat exchanger is installed, which acts as a reflux condenser.

Hydrocarbon vapors rise up the dewaxing tubes, in which titanium spirals of both the same and different directions of rotation are placed, along which the paraffins condense and flow down, creating a reflux stream, which, in turn, irrigates the mass transfer nozzle.

At the same time, the shell-and-tube heat exchanger serves as an irrigation column. Cooling water is supplied to the annulus of the shell-and-tube heat exchanger.

As experiments have shown, such a dewaxing design in which reflux (nozzle irrigation) is formed inside the column rather than being supplied from the outside is most preferable.

In this case, the gas-vapor mixture contains a large amount of inert hydrocarbon gas (up to 15-20%), which lowers the partial pressure of hydrocarbon vapors and worsens the condensation conditions.

The distillation column is also equipped with a reflux condenser and a mass transfer nozzle, and a boiler, heated by fuel gases, is installed at the bottom of the column cube for steaming the light fraction of the vapor-gas mixture.

Heterogeneous catalysis (contact catalysis) characterizes the change in the rate of a chemical reaction when exposed to catalysts that form an independent phase and are separated from the reacting substances by the interface. The most common case is when a solid catalyst (contact) accelerates the reaction between gaseous reactants or the reaction in solution. The catalytic reaction usually proceeds on the surface of a solid catalyst and is caused by the activation of reagent molecules when interacting with the surface. Therefore, the implementation of heterogeneous catalysis requires the adsorption of the components of the reaction mixture from the bulk phase on the surface of the catalyst.

As the experiments showed, the implementation of the mass transfer nozzle in the dewaxing unit and distillation column based on a heterogeneous catalyst made in the form of titanium spirals, which simultaneously serve as a catalyst for the thermal destruction process, as well as loading titanium spirals into the furnace fuel cube collector, makes it possible to increase the yield of light fractions by 3-5%. The free section of the nozzle in the columns is 90-93%, which slightly affects the increase in hydraulic resistance in the system. The pressure at which the process of thermal destruction is carried out is only 0.01-0.07 MPa, which increases the safety of the process.

The list of figures, drawings, diagrams.

The technical solution is illustrated in FIG. 1 - FIG. 8, where:

in FIG. 1 shows a periodic diagram (periodic mode) of operation of the device, on the basis of which a method of thermal destruction is implemented;

in FIG. 2 shows a continuous circuit (continuous mode) of operation of the device, on the basis of which a method of thermal destruction is implemented;

in FIG. 3 shows spiral strips of the left rotation direction;

in FIG. 4 shows spiral strips of the right direction of rotation;

in FIG. 5 shows a cassette with spiral strips, which is placed in the tubes of the heat exchangers;

in FIG. 6 shows a section aa in FIG. 5;

in FIG. 7 shows a bundle of spiral strips that fit into heat exchanger tubes;

in FIG. 8 shows a section BB in FIG. 7.

In FIG. 1 - FIG. 8 the following notation is accepted:

I - the unit of operation of the reactor in cooling mode; II - the unit of operation of the reactor in heating mode; (the boundaries of blocks I and II are indicated by dashed lines); 1 - thermal destruction reactor; 2 - firebox; 3 - burner; 4 - coke collection; 5 - column of catalyst; 6 - heat exchanger to reduce the temperature of the gas mixture; 7 - collection cube with a boiler; 8 - dewaxing agent; 9, 13 - gates; 10 - a heat exchanger for cooling heating oil; 11 - a collection of heating oil; 12 - fuel capacity for the burner; 14 - reflux distillation column; 15 - distillation column; 16 - heat exchanger for cooling diesel fuel; 17 - a collection of diesel fuel; 18 - heat exchanger for gas cooling and condensation of gasoline and water vapor; 19 - gas separator; 20 - a collection of water; 21 - a collection of gasoline; 22 - gas collector (gas holder); 23 - the capacity of the circulating water; 24 - titanium spiral strip of the left direction of rotation; 25 - titanium spiral strip of the right direction of rotation; 26 - cassette with titanium spiral stripes.

Justification of the essence of the utility model.

A. Implementation of the periodic mode (Fig. 1).

In the periodic mode of the device, two blocks are involved: I — the block of the functioning of the thermal destruction reactor in the cooling mode, and II — the block of the functioning of the thermal destruction reactor in the heating mode.

Polygon PE and PP, pre-crushed and flotation-free from impurities of polyvinyl chloride, polyethylene terephthalate, cellulose, rags, rubber and other waste, are loaded through the top hatch (not shown in Fig. 1 - Fig. 8) into one of the thermal decomposition reactors 1 ( Fig. 1).

At the bottom of each thermal destruction reactor 1 is a mobile (removable) furnace 2 with a fuel burner 3, which can operate on either liquid or gaseous fuel of own production.

Next, the contents of the thermal destruction reactor 1 of block I are heated (plastic waste in the form of PE and PP) at a rate of 1.5-4 ° C / minute. Fuel gases with a temperature of 600-900 ° C pass through flame tubes (not shown in Fig. 1 - Fig. 8) of the thermal decomposition reactor 1 and enter the cube boiler 7, and then into the boiler (in Fig. 1 - Fig. 8 not marked) located in the cube of the distillation column 15.

When the temperature in the cube of the distillation column 15 reaches a value of 160-220 ° C, the supply of fuel gases from the thermal destruction reactor 1 of block I is stopped by closing the gate 13. When the temperature in the cube 7 in the range of 300-360 ° C is reached, the supply of fuel gases by shutting the gate is stopped 9.

In the thermal destruction reactor 1 at a temperature of 260-300 ° C, the process of destruction of plastics begins. The degradation products of plastics in the form of a gas-vapor mixture of hydrocarbons from the thermal decomposition reactor 1 are passed into a catalyst column 5, which is a tubular apparatus with flanges loaded with a catalyst — titanium spirals in a cassette, and then into the heat exchanger 6.

When the vapor temperature reaches 300-360 ° C, circulating water is supplied to the heat exchanger 6 to cool the vapor-gas mixture of hydrocarbons. By changing the flow rate of water in the heat exchanger 6, maintain the temperature in the cube 7 in the range of 300-360 ° C.

The gas-vapor mixture of hydrocarbons enters cube 7, where high boiling hydrocarbons pass from it into the liquid phase. Then the vapor-gas mixture enters the dewaxing unit 8, which is a column apparatus, the lower part of which is loaded with a mass transfer nozzle, and a shell-and-tube heat exchanger, which acts as a reflux condenser, is installed in the upper part.

In the annular space of the heat exchanger (in Fig. 1 - Fig. 8 is not indicated) recycled water is supplied, and condensation of hydrocarbons (paraffins) takes place in the tubes of the heat exchanger. Condensed paraffins return back to the cube 7. By changing the water supply to the reflux condenser, the temperature of the vapors at the outlet of the dewaxing unit 8 is maintained in the range of 180-300 ° C.

Then the hydrocarbon vapors enter the distillation column 15, where they are separated into gasoline and diesel fractions. The diesel fraction from the bottom of the column 15 through the heat exchanger 16, cooled by circulating water, enters the collection of diesel fuel 17.

The gasoline fraction in the form of steam and hydrocarbon gas from the top of the distillation column 15 enter the heat exchanger 18 to cool the gas and condensate the vapor of gasoline and water.

The quality of diesel fuel (flash point, fractional composition) is controlled by the temperature of the lower part of the distillation column 15, which is 160-220 ° C.

The quality of the gasoline fraction (density, fractional composition and end of boiling) is controlled by the temperature at the outlet of the distillation column 15. The temperature of the top of the distillation column in the range of 35-100 ° C is maintained by supplying water to the reflux condenser 14 of the distillation column 15. The reflux condenser 14 is a shell-and-tube heat exchanger, in the annular space of which circulating water is supplied, and in the tube space of the reflux condenser 14, condensation of high-boiling hydrocarbons occurs.

In the heat exchanger 18, which is cooled by circulating water, gasoline fraction vapors and water condense. In the gas separator 19, water and hydrocarbon gas are separated from gasoline. Hydrocarbon gas that does not condense is sent to the burner 3 to heat the thermal decomposition reactor 1, and excess hydrocarbon gas is collected in a gas collector (gas tank) 22.

Water and gasoline enter the respective collectors 20 and 21. The heavy fraction (heating oil) is accumulated in the cube 7 and at the end of the thermal degradation process, when the formation of hydrocarbon gas ceases, it is removed through the heat exchanger 10, which is cooled by water, to the heating oil collector 11.

The degradation process of plastics is completed at a temperature of 450-480 ° C. Turn off the fuel supply to the burner and transfer the reactor 1 to the cooling mode.

In FIG. 1 shows that the thermal decomposition reactor 1 of block I is in cooling mode. The mobile (removable) firebox 2 of block I is disconnected from the reactor by lowering it onto the wheels (not shown in Fig. 1 - Fig. 8) and taking it to the side for separate cooling of the thermal destruction reactor 1 of block I. Then the mobile (removable) firebox 2 ( still hot) of block I is connected to a cold (unheated) thermal destruction reactor 1 of block II.

The solid coke residue that remained at the bottom of the thermal destruction reactor 1 of block I, after cooling the reactor, is discharged through the lower hatch of the thermal destruction reactor 1 of block I into the coke collector 4.

While the process of thermal destruction takes place in the thermal destruction reactor 1 of block I, the thermal destruction reactor 1 of block II is loaded with plastic waste and is prepared for launch. As soon as the fuel supply to burner 3 of block I of thermal decomposition reactor 1 of block I is turned off, burner 3 of block II of thermal destruction reactor 1 of block II is immediately turned on after the mobile hot furnace 2 of block I is connected and the process of destruction in the thermal destruction reactor of block 1 II is started . At the same time, the temperature in the cube 7 and the cube of the distillation column 15 is maintained at the same level as in the previous cycle.

After the thermal destruction process in the thermal destruction reactor 1 of block II, it is put into cooling mode, and the thermal destruction reactor 1 of block I is loaded with plastic waste and a new cycle is carried out: "thermal destruction - cooling - unloading of dry residue - loading of plastic waste".

B. Implementation of the continuous mode (Fig. 2)

Polygon PE and PP, pre-crushed (or granular), flotation-free of impurities of polyvinyl chloride, polyethylene terephthalate, cellulose, rags, rubber and other things, are loaded continuously with a screw feeder (not shown in Fig. 1 - Fig. 8) into the thermal decomposition reactor 1 equipped with a furnace 2 and a fuel burner 3, which can operate both on liquid and gaseous fuels of its own production.

Turn on the fuel burner 3 and bring the installation into operating temperature. To accelerate the installation to a predetermined mode, the fuel gases generated during the combustion of fuel are sent to the boiler of cube 7 and distillation column 15.

Operating temperatures in the device are supported in the following ranges:

in a thermal destruction reactor 1, in the range of 450-480 ° C (controlled by changing the fuel supply);

in cube 7 - in the range of 300-360 ° C (regulated by changing the water supply to the heat exchanger 6);

the outlet temperature of the vapor-gas mixture from the dewaxing agent 8 is in the range of 180-300 ° C (controlled by the flow of water into the dewaxing unit of the dewaxing agent 8);

in the cube of the distillation column 15 - in the range of 160-220 ° C (controlled by changing the temperature of the gas mixture after the dewaxing and the upper part of the distillation column 15);

the outlet temperature of the vapor-gas mixture from the distillation column 15 is in the range of 35-100 ° C (controlled by the flow of water into the reflux condenser 14).

Upon reaching operating temperatures in the cube 7 and in the cube of the distillation column 15, the supply of fuel gases to the boiler (in Fig. 1 - Fig. 8 is not indicated) is turned off by closing the gates 9 and 13.

With a continuous mode of operation, the selection of coke from the reactor 1 is carried out continuously using a screw. The discharge of heating oil from cube 7 is produced continuously. At the same time, they maintain the regulated liquid level in cube 7 using the level controller.

All other operations of the device in continuous mode are similar to the operation of the device in periodic mode. The unit is equipped with a closed loop of circulating water and a water tank 23.

As fuel for burners 3, furnace fuel and diesel fraction are used, which are supplied to the fuel tank 12, as well as hydrocarbon gas. Gas from the gas holder 22 can be used in other power plants.

In the process of thermal degradation by this method, a catalyst is used in the form of titanium spirals obtained by twisting strips of titanium 5-20 mm wide and 0.5-1.5 mm thick. The diameter of the spiral is 10-30 mm, the length is 0.1-1 m, and the pitch of the spiral is 10-40 mm. The surface of titanium spirals is pre-treated with 1-2% hydrofluoric acid.

Titanium spirals are loaded into the catalyst column 5, heat exchanger 6, cube-collector 7, dewaxing unit 8, distillation column 15.

Before loading into the column apparatus, titanium spirals are collected in cassettes 26 (Fig. 5 - Fig. 8). The diameter of the cartridge 26 is equal to the inner diameter of the apparatus. As can be seen from FIG. 5 - FIG. 8, spirals are stacked in the cassette parallel to each other and parallel to the side generatrix of the cassette. Those. if the cartridge is standing vertically, then the spirals are located vertically, if the cartridge is horizontal, then the spirals will be horizontal.

In column apparatuses, the arrangement of spirals is predominantly vertical. In the column of catalyst 5, the cartridge 26 is located horizontally. At the same time, for a screw nozzle, it does not matter how to lay it - horizontally or vertically. Moreover, with small values of the diameters of the apparatus (up to 1000 mm) it is more convenient to load the nozzle in the "standing position", i.e. there is a vertical arrangement of the cartridge.

As a catalyst, a heterogeneous catalyst is used in the form of strips of titanium twisted in a spiral, each spiral being preliminarily twisted in one or in different directions, in the second case, spirals of left and right rotation are used, and strips are used, or all are twisted in one or different spirals each side.

Spirals are stacked twisted in one direction each, or with alternating rows with right and left directions of rotation each. The gas-vapor stream passing through such a layer of spirals is divided into many jets. In the second case, these jets are twisted either in one or in different directions upon contact with the spirals, intersect with each other, mix and constantly change the direction of rotation, which intensifies the heat and mass transfer process. In this case, both regular and irregular placement of (bundles) of spirals in the cross section of the apparatus or device (in column apparatus, cassette, heat exchanger tubes) is used.

Also, by combining spirals with alternating unidirectionality and multidirectionality, one can control the direction of motion, speed, concentration of the gas-vapor flow, as well as the rate of the process of heat and mass transfer in the catalyst column.

It was found that the above process most effectively occurs with the claimed design parameters, material and means of treating the surface of the catalyst. Beams of up to 3 x 4-x spirals of different directions of rotation are loaded into the tubes of heat exchangers (Fig. 5 - Fig. 8).

Preheating the collection cube 7 and the distillation column cube 15 with fuel gases, as well as the use of two or more reactors with removable (mobile) furnaces, can speed up the process and ensure the continuity of the hydrocarbon fractionation process.

At the same time, carrying out fractionation (separation) of hydrocarbons in four stages increases the clarity of separation and, accordingly, the quality of the final products that meet current standards.

An example implementation of a utility model.

Use a continuous mode of processing plastic waste. For thermal degradation, a catalyst is used in the form of titanium spirals obtained by twisting strips of titanium 10 mm wide and 1 mm thick. Furthermore, the diameter of the spiral is 10 mm, the length is 0.5 m, and the pitch of the spiral is 20 mm. The surface of titanium coils is pretreated with 1% hydrofluoric acid.

Titanium coils are loaded into the catalyst column 5, heat exchanger 6, cube collector 7, dewaxing unit 8, distillation column 15. Before loading into the column apparatus, titanium coils are also collected in cassettes 26. The diameter of the cassette is equal to the diameter of the apparatus. In the column, the cassettes are mounted vertically on top of each other over the entire height of the nozzle of the column. The tubes of heat exchangers load bundles of 4 spirals of different directions of rotation (Fig. 5 - Fig. 8).

The volume of the collection cube is determined by the dependence:

V _n = 2t · Q _n ,

where Q _n - installation productivity of heating oil in one hour, m ³ / hour; t is the number of hours of continuous operation, hours; V _n - the volume of the collection cube, m ³ .

The calculated values turned out to be equal: Q _n is the productivity of the furnace fuel in one hour Q _n = 0.125 m ³ / h, t = 1 hour, then V _n = 2 · Q _n = 0.25 m ³ .

The screw feeder is turned on and the pre-prepared polygon PE and PP are fed into the thermal decomposition reactor 1. The fuel burner 3 is turned on, using stove or diesel fuel of own production as fuel. Fuel gases from a burner with a temperature of 700 ° C are sent to the boiler of cube 7 and distillation column 15. Water is supplied to the heat exchanger 18.

Next, the contents of the thermal destruction reactor 1 (plastic waste in the form of PE and PP) are heated at a rate of 3 ° C / min. When the temperature in the cube of the distillation column 15 reaches 180 ° C, the supply of fuel gases from the thermal destruction reactor 1 is stopped by closing the gate 13.

When the temperature in the cube 7 reaches 340 ° C, the fuel gas supply to the cube boiler is stopped by closing the gate 9. When the vapor temperature reaches 340 ° C, circulating water is supplied to the heat exchanger 6 to cool the vapor-gas mixture of hydrocarbons. By changing the flow rate of water in the heat exchanger 6, maintain the temperature in the cube 7 340 ° C.

When the temperature reaches 240 ° C after dewaxing, water is supplied to the reflux condenser. When the top temperature of the distillation column 15 is reached, a value of 58 ° C is supplied to the reflux condenser. Upon reaching the operating temperature of 470 ° C in the reactor 1, the fuel burner is transferred to work on hydrocarbon gas of its own production.

The process control mode is transferred from manual to automatic.

The quality of diesel fuel (flash point, fractional composition) is controlled by the temperature of the lower part of the distillation column 15, which is 180 ° C.

The quality of the gasoline fraction (density, fractional composition and the end of boiling) is controlled by the temperature at the outlet of the distillation column 15. The temperature of the top of the distillation column in the range of 58 ° C is maintained by supplying water to the reflux condenser 14 of the distillation column 15. In the heat exchanger 18, which is cooled by circulating water, they are condensed gasoline vapor and water.

In the gas separator 19, water and hydrocarbon gas are separated from gasoline. Hydrocarbon gas that does not condense is sent to the burner 3 to heat the thermal decomposition reactor 1, and excess hydrocarbon gas is collected in a gas collector (gas tank) 22.

Water and gasoline enter the respective collectors 20 and 21. Diesel fuel through the heat exchanger 16, which is cooled by water, enters the collector 17. The heavy fraction (heating oil) from the cube 7 is discharged through the heat exchanger 10, which is cooled by water, into the furnace fuel collector 11. The selection of coke from the reactor 1 is carried out continuously using a screw in the coke collector 4.

The specific fuel consumption for the given embodiment of the invention is 70%, water 50%, and the yield of light products (gasoline and diesel fuel) is 8% higher compared to the prototype.

Industrial application.

Thus, when using the utility model, an improvement in quality and an increase in the yield of finished products — gasoline and diesel fuel — are achieved by using effective designs, operating parameters, and procedures at the main stages of the invention, in particular, at the fractionation stage.

Preheating the collection cube 7 and the distillation column cube 15 with fuel gases, as well as the use of two or more reactors with removable (mobile) furnaces, can speed up the process and ensure the continuity of the hydrocarbon fractionation process.

At the same time, carrying out fractionation (separation) of hydrocarbons in four stages increases the clarity of separation and, accordingly, the quality of the final products that meet current standards.

The present invention is more cost-effective than the invention of the prototype, since the specific fuel consumption for the process is 70-75%, and water 50-60% compared with the method and device of the prototype. Also, in the developed technical solution, the yield of light products (gasoline and diesel fuel) is 5-8% higher, the quality of gasoline complies with GOST R 51105-97 "Unleaded gasoline", and diesel fuel complies with GOST 305-82 "Diesel fuel L-0.05- 40. "

Claims (5)

1. Device for thermal destruction of waste polyethylene and polypropylene, including a reactor for thermal destruction of polymer raw materials with devices for loading raw materials and unloading coke, a fractionation unit for the destruction of polymer raw materials, a heat exchanger unit, equipment for thermal catalysis, and a feed unit with pipelines for refrigerant circulation in the form of water, characterized in that the device comprises at least two thermal decomposition reactors, which are connected in parallel with by a complete technological cycle: heating - thermal destruction - cooling - coke unloading - loading of raw materials; in addition, each of the reactors is equipped with a mobile or removable furnace, which is configured to be disconnected from the first reactor and connected to the second reactor, and the fractionation unit for the degradation products of the polymer feedstock, namely the vapor-gas mixture, consists of a water-cooled heat exchanger connected in series, in which scheme of countercurrent motion of phases with a downward flow of a vapor-gas mixture of hydrocarbons, a collection tank of hydrocarbons with a boiler, a dewaxing unit consisting of a nozzle the lower part and the reflux condenser installed in the upper part and made in the form of a shell-and-tube heat exchanger, a distillation column for separating fractions of diesel fuel and gasoline, consisting of a packed lower part and a reflux condenser installed in the upper part and made in the form of a shell-and-tube heat exchanger, and a boiler installed in cubic column, tubular vertically mounted heat exchanger with a downward movement of gasoline vapor and hydrocarbon gas, the device contains a heterogeneous cat a lyser in the form of strips of titanium twisted in a spiral, each spiral pre-twisted in different directions, forming spirals of left and right rotation, the strips of titanium are placed in the collection cube, in the tubes of the heat exchanger, in which high-boiling hydrocarbons from the vapor-gas mixture are condensed, in tubes of the reflux condenser of the dewaxing and in the tubes of the reflux condenser of the distillation column. 2. The device according to p. 1, characterized in that, as a heterogeneous catalyst, the device comprises a catalyst made in the form of strips of titanium with a width of 5-20 mm, a thickness of 0.5-1.5 mm, which in a twisted form have a diameter of 10-30 mm, length 0.1-1 m, with a spiral pitch of 10-40 mm. 3. The device according to claim 5, characterized in that the strips of titanium twisted in a spiral are contained as a mass transfer nozzle in the dewaxing apparatus and in the distillation column. 4. The device according to p. 1, characterized in that the dewaxing device is made in the form of a column apparatus, the lower part of which is filled with a mass transfer nozzle made in the form of titanium spirals and having a free section of 90-93%. 5. The device according to claim 1, characterized in that a shell-and-tube heat exchanger is installed on top of the dewaxing device, which serves as a reflux condenser, and titanium spirals of different directions of rotation are placed in the tubes of the dewaxing device.

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