RU2460743C2 - Process and apparatus for processing rubber-containing wastes - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: rubber-containing wastes are processed via thermolysis of rubber crumbs at 350-400°C in the medium of circulating superheated and evaporated gasoline at pressure close to atmospheric pressure. The rubber crumbs disintegrate into technical carbon, synthetic crude oil and hydrocarbon gas. The formed technical carbon with adsorbed oil is blown with air, wherein the textile cord is completely burnt, a portion of the oil burns and the other portion is released with flue gases. The rubber-containing wastes are processed in an apparatus with a reactor with a spiral motor.

EFFECT: invention enables continuous processing of rubber for a long period of time, simplifies the process and apparatus, and improves environmental safety of the process.

5 cl, 4 dwg

Description

The invention relates to the chemical, petrochemical and other industries, as well as to utilities, to the area of activity of people where polymer-containing wastes are generated, can be used in the processing of tires that have expired, as well as in the processing of waste in their manufacture.

Known methods and devices for the pyrolysis of polymer-containing (and primarily rubber-containing) waste in reactors at temperatures above 500 ° C. In this case, fuel oil, diesel and gasoline fractions of hydrocarbons, hydrocarbon gas and carbon black (soot) are obtained. However, the pyrolysis of rubber at a temperature of 500 ° C and above creates conditions for cracking polymers and oils up to the formation of coke, which affects the quality of carbon black (soot). In addition, heating the waste to a high temperature requires complex technical solutions and is economically disadvantageous.

Pyrolysis is usually carried out on batch plants with their inherent disadvantages of input-output of reagents, the frequency of heating and cooling of the reagents, and the design of the installation.

The diesel and gasoline fractions contain a large amount of unsaturated hydrocarbons and therefore cannot be used as components of commercial fuels.

Known "Method for processing rubber-containing waste" [1] and "Production of carbon black, components of hydrocarbon fuels and raw materials for the chemical industry from raw materials - rubber-containing industrial and household waste" [2].

They suggest thermolysis of rubber in a fluidized bed in a stream of heavy hydrocarbon gas containing alkyl aromatic compounds (toluene) at a temperature and pressure close to critical. The application of this method and production has significant advantages over pyrolysis.

- Continuity of the process.

- Lack of additional chemicals other than rubber itself.

- Production of carbon black without coke.

- Low process temperature.

- Reliable separation of liquid, gaseous and solid reaction products.

However, the fluidized bed (PIC) imposes a number of disadvantages.

- A large ratio of raw materials: circulating coolant-fluidizing agent.

- Difficulty in removing heavy components from PIC.

- High pressure in the thermolysis reactor.

- The presence of heavy hydrocarbons adsorbed by porous carbon black (soot).

The above “method” and “production” are accepted by us as a prototype.

Known transport systems with an axle-free spiral, widely used around the world for carrying bulk materials.

The advantages of spiral conveyors are as follows.

- Lack of stagnant zones.

- Silent.

- Low power consumption.

- Simple installation, long life and trouble-free operation.

- Gentle product transportation.

- And etc.

The essence of the method is the thermolysis of rubber at a temperature of about 370 ° C in an environment of hydrocarbon gas, a coolant.

Rubber-containing waste is crushed to the size that provides the most complete removal of cords, the latter in the form of scrap metal and textile wool to be sold.

The crumb rubber is thermolysed to produce products: carbon black (soot), synthetic oil and a small amount of hydrocarbon gas. Carbon black (soot) is a porous product that contains all the solid additives that are not decomposed during thermolysis, which are introduced during the preparation of crude rubber, and a significant amount (up to 15% by weight) of adsorbed heavy hydrocarbons - oils, both introduced into rubber during its manufacture, and resulting from thermolysis, because carbon black with the oils contained in it is in most cases unacceptable for further use as a filler or dye, then the oils from carbon black must be removed. It is also necessary to remove the remnants of textile cord from it. To do this, it is proposed to blow hot carbon black after thermolysis with a certain amount of air. At the same time, oils are desorbed at a local high temperature, part of them burns out, and part is carried out by combustion products (flue gases) and is one of the components of synthetic oil. The ratio between the quantities of carbon black and the air supplied to the purge is quite certain and is optimally 8 liters of air per 1 kg of carbon black.

This figure was obtained during the operation of a pilot plant operating according to the scheme declared in this application and fully consistent with the real industrial one.

With less air, not all oils are removed and the quality of carbon black is lost. With a larger amount, more oils are burned and thereby the yield of synthetic oil is reduced. In addition, part of the carbon black (the smallest particles) burns down, which also reduces the yield of marketable products.

When burning residual oils, residues of textile cord are also burned.

The thermolysis process is proposed to be carried out in a reactor, which is a spiral conveyor, in which the spiral is the mover of raw materials and solid thermolysis products. The reactor consists of two sections. The section of the reactor in which the thermolysis of rubber occurs is the thermolysis section. The thermolysis temperature is 350-400 ° C, the pressure is close to atmospheric.

The section of the reactor - the section for the refinement of carbon black - bringing carbon black to a commodity condition, in which desorption and burning of oils, as well as residues of textile cord from carbon black, takes place.

Both sections can be combined with a single mover. In the gap between them, a filter is installed through which the gas flows of both sections are passed.

Carried away by these gas flows and filtered carbon black particles fall down and return to the spiral conveyor.

The above measures allowed to reduce the minimum frequency of circulation of the coolant from 4 to 2.5.

When implementing the proposed method and creating the proposed installation, the following were obtained: improving the parameters of the thermolysis process, simplifying, facilitating, cheapening the design of the main elements of the installation, implementing a more compact and convenient arrangement of units, simplifying and cheapening the operation and process control.

The installation scheme that implements the proposed processing method is presented in Fig. 1.

The main reactor apparatus is made in the form of a screw conveyor 1.

2. Mover of raw materials and solid products: spiral (coil spring).

3. Drive mover 2 - gear motor.

4. Reactor section — thermolysis section.

5. The union of input of raw materials - rubber crumb.

6. Inlet fitting for circulating heat carrier - gas of evaporated and superheated gasoline.

7. Reactor section - section for bringing carbon black (soot) to market condition

8. Inert gas inlet fitting.

9. Union outlet carbon black.

10. The filter separator gas and dust.

11. Gas outlet fitting.

12. Air inlet fitting.

13. Shirt supplying heat from the circulating coolant through the wall of the reactor

14. A shirt of water or air cooling of carbon black.

15 - heat exchanger.

16 - reboiler.

17 - distillation column.

18 - synthetic oil.

19 - circulating coolant.

20 - oven.

21 - refrigerators.

22 - gas-liquid separators.

23 - pumps.

24 - compressor.

Figure 2 shows a diagram of the reactor group of the installation with separate sections of the thermolysis reactor and a refining section.

25 - a separate section for upgrading carbon black.

26 - a separate section of thermolysis of rubber.

27 - spiral - mover section thermolysis.

28 - spiral - mover section ennoblement.

Fig. 3 shows a reactor consisting of one independent section of thermolysis.

29 - hopper.

30 - carbon black outlet fitting.

Fig. 4 shows an independent section for upgrading carbon black.

31 - hopper unfinished carbon black.

32 - feeder-dispenser.

The operation of the thermolysis unit is as follows: the rubber crumb is fed by a metering feeder (32) to a spiral conveyor reactor consisting of two sections, a thermolysis section (4) and a section for bringing carbon black (soot) to marketable condition (7).

The mild conditions of thermolysis make it possible to obtain the main marketable product, carbon black without unwanted coke, the formation of which begins at temperatures above 400 ° C from oils and heavy thermolysis products.

The crumb rubber, and then the solid product of its decomposition - carbon black moves along the conveyor (1) from the nozzle (5) to the nozzle (9) due to the rotation of the spiral (2), driven by a gear motor (3). The hydrocarbon reaction products together with the heat carrier gas are removed from the reactor through a bag filter (10) and a fitting (11), and carbon black deposited on the filter falls down into the main part of the carbon moved by the spiral. Synthetic oil is removed together with the coolant, and the amount of coolant is determined so that the oil is removed in the gas phase according to the conditions of phase equilibrium.

A certain amount of oil (oils) remains in carbon black in an adsorbed form. Removing this part of the oil from carbon black is carried out in section (7), between the filter (10) and the fitting (12), by desorption and combustion. Flue gases are discharged through the filter (10) together with the coolant. The countercurrent movement of air and carbon black makes it possible to carry out the desorption of oils by flue gases from the combustion of oils by nitrogen, CO ₂ , and water vapor, and the burning of residual oils is carried out with atmospheric oxygen.

When oils are burned with oxygen from the air, the remnants of the textile cord are also burned.

Between the fittings (12) and (8), carbon black, moving towards the fitting (9), is cooled by water or air circulating through the jacket (14). This prevents overheating of carbon black.

Purified from oils, cooled to a temperature that allows it to be packed in bags or in Big-Beg, it is discharged through the fitting (9) in the commodity condition.

Thus, the proposed method and its implementation in the proposed installation allows you to get marketable products - synthetic oil and carbon black, purified from oils and residues of textile cord.

Thanks to the use of a spiral conveyor as a reactor, a continuous process of supplying raw materials - crumb rubber and the output of reaction products is carried out. It should also be noted the possibility of carrying out a process with a high degree of tightness, eliminating the emission from the system and environmental pollution by oil products and soot.

Gaseous products discharged through the nozzle (11) are sent through a heat exchanger 15), a reboiler (16) to a distillation column (17), where they are separated into gas, synthetic oil (18) and the circulating heat carrier - gasoline fraction (19). Heat recovery of thermolysis products to the thermolysis section through the jacket on the pipe of the thermolysis section 7 is possible.

The heat carrier is heated in a heat exchanger (15), evaporated and overheated in an oven (20) and sent first to a jacket (13) to maintain the thermolysis process, and then to a fitting (6). On the way between them, additional heating of the coolant in the furnace is possible.

To ensure intensive cooling of carbon black and fire and explosion safety, a small amount of an inert gas, nitrogen, is introduced through the nozzle (8).

Hydrocarbon gas (17), a thermolysis product, together with flue gases (7) is used for backflushing the filter (10), for burning in an oven (20) or is sent to a torch for combustion.

To completely extract the gasoline fraction of synthetic oil, the waste gas is compressed in a compressor (24), cooled in a refrigerator (21) until heavy condensation occurs, which is returned to the circulating coolant (19).

In order to save space, the area occupied by the reactor may separate sections (4) and (7). In this case, the outputs of the products of thermolysis and refining gas also in a single filter separator 10 carbon black. Sections can be located at any angle to each other (Fig. 2).

If necessary, sections can be used independently of each other. Figures 3 and 4 show separate sections of thermolysis and refinement, which can be operated independently of each other, which makes it possible to refine the carbon black obtained in any other plants.

As shown by studies in a pilot installation, it is possible to process not only rubber, but also other polymeric materials.

Based on the results of work on a pilot plant with a capacity of up to 20 kg of rubber crumb per hour, the following conclusions can be made.

1. Commercial products obtained: carbon black (soot) and synthetic oil.

2. Reliable continuous processing of rubber for a long time is shown.

3. Achieved compact apparatus, environmental safety, good process control.

4. The amount of circulating coolant is reduced several times in comparison with fluidized bed plants.

LITERATURE

1. RU 2220986 C1.

2. RU 2006146634 A.

Claims (5)

1. The process of processing rubber-containing waste by thermolysis of rubber crumb at a temperature of 350-400 ° C in a medium of a circulating hydrocarbon coolant - superheated and vaporized gasoline, while the raw material - crumb rubber decomposes into a solid product - carbon black, synthetic oil and hydrocarbon gas the fact that thermolysis is carried out at a pressure close to atmospheric, the process of bringing carbon black to market condition is carried out by desorption and partial burning of oils adsorbed technically carbon during thermolysis, air blowing, complete combustion of textile cord with atmospheric oxygen and removal of some oils by combustion products - flue gases. 2. Installation for processing rubber-containing waste, consisting of a rubber crumb dispenser, a reactor, a filter, a furnace, a distillation column, heat exchange, separation equipment, pumps, a compressor, characterized in that the reactor consists of two sections: a rubber crumb thermolysis section and a technical finishing section carbon to commodity condition; both sections are combined by a common filter located between the sections, as well as located inside the reactor - spiral conveyor - solid product propulsion device, while a rotating spiral is used as a propulsion device, or both sections are used independently of each other, each equipped with its own filter and its own spiral . 3. Installation according to claim 2, characterized in that in the middle of the section for bringing carbon black to commodity condition, there is an air inlet fitting, and at the end of the section there is a outlet for finished carbon black, while a carbon or water cooling shirt is placed between them . 4. The installation according to claim 2, characterized in that an inert gas inlet fitting is installed at the outlet of the finished carbon black from the refinement section. 5. Installation according to claim 2, characterized in that they use a stainless steel filter with short-pulse purging with gas obtained in the process of thermolysis by compressing it in a compressor to separate the condensate of the heat carrier component of synthetic oil from it.

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