HK1115897A - Method and installation for pyrolisis of tires - Google Patents

Abstract

The present invention relates to a method and apparatus for waste tyres pyrolysis wherein whole tyres are directly heated with flue gases from the combustion of pyrolysis gases, in a tunnel type furnace. The process produces thermal energy, carbon black and mineral oil; the cooled flue gases are cleaned from sulfur oxides before released into the atmosphere.

Description

Method and device for pyrolysing tyres

Technical Field

The invention relates to a method for thermally decomposing waste tyres and to a device for carrying out said method, and is suitable for producing thermal energy, carbon black and mineral oil in tyre recycling. The carbon black obtained can be used for the production of rubber articles, and mineral oil-as fuel or softener in the production of such articles.

Background

Document GB2303859 discloses a process for the pyrolysis of tyres for the treatment of whole or cut-into-pieces, by indirectly heating the tyres in a horizontal tunnel pyrolysis oven (pyroliser) to a temperature of 200-1000 c, preferably 300-800 c, and feeding the tyres contained in a mobile trolley into the pyrolysis oven. When the tire is heated, it thermally decomposes and may obtain pyrolysis gases, mineral oil vapors expelled from the pyrolysis gases, and solid carbon. The process is divided into three stages: heating the tyre, self-pyrolysis process and cooling the obtained solid carbon. Indirect heating can be achieved by burning part of the pyrolysis gas to obtain hot flue gas. The received pyrolysis gas is stripped of sulfur oxides.

The document GB2303859 also shows a tyre pyrolysis apparatus comprising a pyrolysis oven formed as a horizontal oven tunnel, in which a trolley with tyres is placed. The channel is heated from the outside with hot flue gases. A moving barrier (screen) divides the pyrolysis furnace into heating and pyrolysis zones and a cooling solid carbon zone. The pyrolysis unit comprises burners for burning pyrolysis gases, equipment for removing sulphur oxides from flue gases, a condenser for separating mineral oil, and a magnetic field system for removing metal wires from the obtained carbon products.

The known methods and devices use an indirect heating of the tyres, which is effected by the walls of the pyrolysis furnace, for which reason the temperature of the exhaust gases released is higher, which is responsible for the increased energy loss. Furthermore, the walls of the pyrolysis furnace, which are heated to high temperatures, crack the hydrocarbons obtained in the pyrolysis, which leads to a reduction in the yield and a reduction in the quality of the carbon products.

Disclosure of the invention

The technical problem to be solved consists in increasing the energy efficiency of the recovery of the waste tyres by pyrolysis, while improving the quality of the solid carbon residue obtained, so that it is suitable for use as carbon black in the rubber industry.

The present invention can be explained by employing a method of pyrolyzing an entire tire, in which the entire tire is heated to a temperature of 400-950 ℃ and subjected to pyrolysis. The pyrolysis gas, the mineral oil vapors emitted from the pyrolysis gas, and the solid carbon are finally obtained. Mineral oil is separated off during cooling of the pyrolysis gas. The heat required for pyrolysis is supplied by flue gases resulting from the combustion of pyrolysis gases. The sulfur oxides obtained in the process are separated off.

According to the invention, the method is typically characterized in that: the tire is directly heated to the temperature of 600-950 ℃ by the flue gas in transverse countercurrent, wherein the temperature is 650-750 ℃, and the flue gas is added with steam with the concentration of 15-40%, preferably 18-30%. In the process pyrolysis gas is obtained, which is cooled to a temperature of 150-300 ℃ and then split into two streams. One stream is additionally cooled to a temperature of 80-100 c, whereby part of the mineral oil contained in this stream condenses, after which this stream is mixed again with another uncooled pyrolysis gas stream. The gases obtained are being combusted, only part of the hot flue gases is used for pyrolysis, and the cooled gases are freed from sulphur oxides and released to the atmosphere. The solid carbon obtained provides carbon black suitable for use in the rubber industry.

According to the invention, the device for carrying out said method comprises a horizontal pyrolysis furnace formed as a furnace tunnel inside which the trolleys with the tires move, the pyrolysis furnace itself being divided by a mobile screen into a heating and pyrolysis zone and a cooling carbon black zone. The plant also provides a burner for burning pyrolysis gases, a device for removing sulfur oxides from flue gases and a condenser for separating mineral oil.

According to the invention, the device is typically characterized in that: the pyrolysis furnace is insulated and the trolleys have vertical partitions (partitions) which are placed on rails and sealed to the walls of the pyrolysis furnace. Channels for conveying and discharging gases and channels enabling the gases to flow transversely through the pyrolysis furnace are located on both sides of the pyrolysis furnace. All channels are connected to the pyrolysis furnace through holes evenly distributed in the side walls thereof. Within these walls are constructed dense walls of a length not less than the length of a single cart. The heating and pyrolysis zone, the cooled carbon black zone, as well as the preheating zone, the air blowing zone and the separated carbon black zone are formed by the dense walls and the vertical portion of the cart. The channel for discharging the cooled flue gases is connected to a chimney. The channel supplying the flue gas of the preheating zone is connected to the channel discharging the flue gas from the zone cooling the carbon black. The channel for feeding the flue gas into the cooling carbon black area is connected to a chimney through a flue. A water supply pipe ending with a sprinkler is also connected to this flue. The pyrolysis gas passage is connected to the combustion chamber with the burner through the flue, and the pyrolysis gas valve is mounted on the flue. The condensation device for separating mineral oil, which consists of a direct cooler and a heat exchanger, is connected on both sides of the valve. The combustion chamber with the burner is directly connected to a boiler, which in turn is connected to a channel for feeding high temperature gas into the pyrolysis furnace and also to a contact economizer. The economizer is also connected to a device for removing sulphur oxides from the flue gases, which device is in turn connected to a stack. The apparatus also includes an air humidifier connected to the first fan, to the combustion chamber with the burner, and to the contact economizer. The air-blowing zone is connected to a second air blower via an air supply channel. This zone is also connected to the air discharge channel and the latter to the chimney. According to a preferred mode of carrying out the device, the trolley has a profile connected to the floor and to the vertical partition. The partitions are shaped according to the section of the pyrolysis furnace and are sealed to the furnace by plates connected to "hinges" and tensioned by tie rods. Each trolley has wheels. The horizontal axis of the diameter of the tires loaded into the trolley is perpendicular to the axis of the pyrolysis furnace. The tyre is supported and stabilized by stays (strut), preferably made of expanded metal sheet.

The advantage of the method and device for pyrolysing tyres compared to heating by walls is that the tyre heating is done directly by gas, which reduces energy consumption. The addition of steam to the gas mixture and lowering the temperature of the pyrolysis furnace reduces the many-sided adverse effects of cracking on the quantity and quality of the products obtained from pyrolysis, and the steam in the plant can be reused. The device is particularly effective for pyrolysing whole tyres, since the trolleys used for feeding the tyres into the pyrolysis furnace are provided with means which do not allow crushing of the tyres. When the tire is softened by heating, the heated surface of the tire is not reduced.

Drawings

The invention is illustrated by the accompanying drawings in which:

fig. 1 shows a flow chart of an apparatus according to a mode for carrying out the invention.

Figure 2 shows a front view of the trolley.

Figure 3 shows a side view of the trolley.

Best Mode for Carrying Out The Invention

As shown in fig. 1, an embodiment of a tire pyrolysis apparatus according to the present invention includes a pyrolysis furnace 2 that provides an insulated horizontal furnace channel. The trolley 1 runs on rails inside the pyrolysis furnace. The apparatus further comprises a combustion chamber 33 with a burner, a boiler 34, a contact economizer 42, an air humidifier 40, a direct cooler 29, a heat exchanger 24, fans 19, 39, 56 and pumps 26 and 38. The trolley 1 is constituted by a profile forming a frame (frame), as shown in fig. 2 and 3. To which the bottom plate 12 made of densified metal sheet and the vertical partition 50 at the rear of the trolley 1 are connected. This partition is formed according to the cross section of the pyrolysis furnace 2 and is sealed to the walls of the pyrolysis furnace by a plate 51 inclined in the opposite direction to the movement of the trolley 1. The plate 51 is connected to the trolley 1 by a "hinge" and is tensioned by a tie rod. Each trolley 1 has wheels 52. The trolley is provided with tires 49, the horizontal axis of the diameter of the tires 49 is perpendicular to the axis of the pyrolysis furnace 2. The tire 49 is supported by stays 54 made of expanded metal and is stabilized by brackets 53 made of tubes. Channels 4, 5, 6, 8, 9, 10, 11 and 57 for feeding and discharging gases to and from the pyrolysis furnace and channels 7 for effecting lateral movement of the gases are located at the sides of the pyrolysis furnace. The height of the channels 4, 5, 6, 7, 8, 9, 10, 11 and 57 is the same as the height of the pyrolysis furnace 2. The channels 4, 5, 6, 7, 8, 9, 10, 11 and 57 are connected to the pyrolysis furnace by evenly distributed holes in their walls, as is often the case with those channels. Between adjacent channels 7 and between adjacent channels 6 and 7, 7 and 8, the walls of the pyrolysis furnace 2 are formed as dense walls 3. The distance between adjacent lanes mentioned above is equal to a cart length of 1.05. The zones are formed by the opposed solid walls 3 and the vertical partitions 50 to divide the pyrolysis furnace 2 into five zones: a preheating zone 58, a heating and pyrolysis zone 59, a cooled carbon black zone 60, an air blowing zone 61, and a separated carbon black zone 62. A dense wall 3 and a vertical partition 50 ensure that the air flow through the tyre 49 is altered. The separated carbon black region 62 is connected to the storage bin 13. The storage silo 13 is also connected to a line 17 for discharging carbon black from the apparatus. The channel 4 is intended to discharge cooled flue gases and it is connected to a first flue 44 of cooled flue gases through a second flue 21 of cooled flue gases, said first flue 44 being connected to a stack 63. A flue gas valve 45 is mounted on the first flue 44 for cooling flue gases. The channel 5 is intended to feed flue gases into the tyre preheating zone 58 and is connected to the channel 10 for discharging flue gases of the cooled carbon black zone 60 through the third flue 14 for cooling flue gases. The channel 9 is intended to feed the flue gas into the cooled carbon black zone 60 and is connected to the first flue 44 for cooled flue gas through a fourth flue 20, which is connected before this connection to the second flue 21 for cooled flue gas. A water supply pipe 64 for supplying water, the end of which is provided with a sprinkler, is connected to the end of the fourth flue 20. The fan 19 is connected to a second flue 21 for cooling the flue gases. The pyrolysis gas channel 6 is connected to a combustion chamber 33 with burners via a first pyrolysis flue 28. The pyrolysis gas valve 31 and the pyrolysis gas fan 56 are connected to the flue 28 before the combustion chamber 33 with the burner. The combustion chamber 33 with the burner is directly connected to the boiler 34. The boiler 34 is connected to the channel 8 by a flue 36 for hot flue gases, the channel 8 being used to feed the hot flue gases into the pyrolysis furnace 2. Flues 65 and 32, respectively, for conveying and discharging pyrolysis gases to the direct cooler 29 are connected to both sides of the pyrolysis gas valve 31 located on the first pyrolysis flue 28. The cooler 29 is also connected to a line 27 for discharging condensate. The conduit 27 is also connected to conduits 25 and 30 for transporting and discharging the hot and condensed oil condensates, respectively, to the heat exchanger 24. The pump 26 is mounted on the thermal condensate transfer line 25. Pipes 22 and 23 for conveying cold water and for discharging hot water, respectively, are also connected to the heat exchanger 24. The air humidifier 40 is connected to the first air supply fan 39 through a first air duct (air duct) 55. The air humidifier 40 is also connected to the combustor 33 with a burner through a second air duct 35, and is connected to the contact economizer 42 through a cooling circulation water pipe 37, and a water pump 38 is installed on the cooling circulation water pipe 37. The air humidifier 40 is also connected to a contact economizer 42 through a hot water pipe 41. The contact economizer 42 is also connected to a first flue (cook stack)44 for discharging flue gas through a fifth flue gas duct 43 before a flue gas valve 45. The contact economizer 42 is also connected to a device 47 for removing sulfur oxides from the flue gas through a sixth flue stack (flue stack) 46. The device 47 is in turn also connected, via a seventh flue 48, after the flue gas valve 45, to the first flue 44 for discharging flue gases to a stack 63, but before this position, the flue is connected to the fourth flue 20 for cooling the flue gases. The air-blowing zone 61 is connected to the secondary air duct 16 through the air supply passage 11 and to the second air blower 15 through the secondary air duct 16. The air blowing zone 61 is also connected to the exhaust passage 57, and the exhaust passage 57 is connected to the third air passage 18. After the exhaust channel 57 is connected to the second flue 21 for cooling the flue gases, it is connected to the first flue 44 for discharging the flue gases.

Industrial applications

The above description is implemented in the following manner:

the pre-cleaned and dried tire 49 is mounted on a stay 54 on the cart 1. The loaded cart is fed into the pyrolysis furnace 2 and sealed to the walls of the pyrolysis furnace by plates 51. The flue gases are fed into the pyrolysis furnace 2, counter-currently to the trolleys 1 loaded with tires 49, the temperature of the inlet section of the pyrolysis furnace 2 being maintained at 650 ℃. The flue gas contains 25% steam. The pre-cooled gases emerge from the boiler 34 and are sent in transverse counterflow to the tyres 49 along the hot flue gases duct 36, through the perforated wall of the channel 8 for feeding the hot gases into the pyrolysis furnace 2. They proceed in the following mode: the first passage (pass) through the tyre 49 to the air channel 7-effects the lateral movement of the air. From the air channel 7, the transverse movement of the air is effected again through the tyre 49 to the opposite channel 7 and again to the last channel 7, the transverse movement of the air being effected continuously. From the channel 7 and through the tyre 49, the gas enters the pyrolysis gas channel 6. As the gases move through the tire, they cool to 170 ℃. At this temperature, the pyrolysis gases obtained leave the pyrolysis furnace 2 through the pyrolysis gas channel 6 and through the first pyrolysis flue 28. Part of the gases of the first pyrolysis flue 28 are diverted via a pyrolysis gas valve 31 to a direct cooler 29, where they are cooled to 85 ℃ by means of circulating cooled pyrolysis oil. Part of the oil carried by the gas condenses during cooling and is separated from the apparatus by a line 27 for discharging the condensed oil. The treated gas is mixed with untreated pyrolysis gas and fed through a pyrolysis gas blower 56 into the combustion chamber 33 with burners. The pyrolysis oil which has condensed in the direct cooler 29 is fed through the condensate pump 26 to the heat exchanger 24, where it is cooled indirectly with water to 87 ℃. The water that has been used for cooling is conveyed along a cooling water conveying pipe 22 to a heat exchanger 24 and is discharged out of the heat exchanger 24 along a pipe 23 at a temperature of 80 ℃. The used heat may be used for domestic or district heating.

The pyrolysis gas, which is mixed with the preheated air flow containing 24% steam and supplied from the humidifier 40 through the second air duct 35, is ignited and burned in the combustion chamber 33 with burner. The combusted flue gases are fed to a boiler 34 where they discharge heat for steam production. The partially combusted flue gases are separated in the boiler 34 before their final cooling and enter the pyrolysis furnace 2 through the hot flue gas duct 36 at a temperature of 650 ℃. The remaining flue gas leaves the boiler 34 at a temperature of 110 ℃ and is diverted along a flue gas duct 43 with the help of a flue gas valve 45 into the contact economizer 42. Where they are cleaned with chilled circulating water heated up to 67 c. The flue gas cooled in the contact economizer enters the plant for removing sulphur oxides 47 from the flue gas through a sixth flue duct 46 and is thereafter forwarded through a seventh flue duct 48 and discharged to the atmosphere through a stack 63.

The heated water in the contact economizer is fed to an air humidifier which heats the air delivered by the first air supply fan 39 in a counter-current manner, heating the air to a temperature of 66.5 c and humidifying it to 25%. At that temperature and humidity level, the heated air is fed through the second air duct 35 to the burner in the burner-equipped combustion chamber 33.

The tyres 49 ready to undergo pyrolysis are loaded into the trolley 1 and enter the rails of the first separation zone. From there, they pass through a tire preheating zone 58 where the fumes heat them to a temperature of 60 ℃. The flue gases which have been cooled to a temperature of 110 c there are passed through the second flue 21 for cooled flue gases to the stack 63. The tyre preheating zone 58 is separated from the heating and pyrolysis zone 59 by means of a second separation zone between the opposite barriers 3. When the tires are treated with hot flue gases, they are converted to pyrolysis gases during this treatment, which pyrolyze the tires. The vapors of liquid pyrolysis products and pyrolysis gases obtained in the process are mixed with the flue gases and discharged as pyrolysis gases through the pyrolysis gas channel 6. The metal cords of the tire remain in the vehicle 1, as well as the carbon black and other fillers added to and contained in the tire production. Exposed to the high temperature and high humidity content of the conveying fumes, the carbon black is purified and becomes suitable for use in the rubber industry-for secondary use in the production of rubber articles. As the trolleys 1 pass through the pyrolysis furnace 2, each respective trolley 1 enters the next separation zone 3. From there, it passes through a cooling trolley and a cooling carbon black zone 60 and is cooled to a temperature of 110 ℃ by means of flue gas conveyed through the fourth flue gas duct 20. Well dispersed water is injected through the water supply pipe 64 ending with a sprinkler to improve cooling of the flue gas. Those gases cooled to a temperature of 95 c along the flue 14 enter the tire preheating zone 58.

Following the fourth separation zone 3, the trolleys 1 enter the zone 61 to be blown by the air delivered by the second air blower 15. The heated air flow is fed through the third air duct 18 into the chimney 63. The cooled trolleys 1 pass through the fifth separation zone 3. From the fifth separation zone 3, the trolley 1 enters a zone 62 for separating the carbon black. The carbon black is removed from the cart and fed to a storage silo 13, from which it is discharged through line 17 for separation of the wire and subsequent grinding. The trolley 1 is reloaded with cleaned and dried tyres 49 and fed again into the pyrolysis furnace 2.

About 770 kg of carbon black and about 900kWh of heat in the form of steam can be obtained by treating 2.2 tons of tires. When a fraction of the pyrolysis oil is refined as the end product, the amount of heat obtained is correspondingly reduced.

Claims (3)

1. A method for pyrolysing whole tyres, wherein the tyres are heated to a temperature of 400-: the tyre is directly heated in transverse countercurrent with flue gases having an initial temperature of 600-.

2. An apparatus for pyrolysis of whole tires, the apparatus comprising a pyrolysis furnace forming a horizontal furnace channel, in which there are provided a moving cart carrying tires and a moving barrier dividing it into a heating and pyrolysis zone and a cooled carbon black zone, the apparatus further comprising a burner for burning pyrolysis gases, a device for removing sulfur oxides in flue gases and a condensation device for separating mineral oil, the apparatus being characterized in that: the pyrolysis furnace (2) is thermally insulated and the trolley (1) has vertical partitions (50), the trolley is placed on rails and sealed to the walls of the pyrolysis furnace, and channels (4, 5, 6, 8, 9, 10 and 57) for conveying and discharging gases and channels (7) for achieving a lateral movement of gases through the pyrolysis furnace (2) are located on both sides of the pyrolysis furnace, and all channels are connected with the pyrolysis furnace (2) through holes evenly distributed in its side walls, dense walls (3) of a length not less than the length of trolley (1) are also formed in these walls, and the pyrolysis furnace (2) is divided into a heating and pyrolysis zone (59) and a cooling carbon black zone (60), and a preheating zone (58), an air blowing zone (61) and a carbon black zone (62) by means of the opposite dense walls (3) and the vertical walls (50) forming partitions, the channel (4) is designed for discharging cooled flue gases and it is connected to a chimney (63); the channel (5) is designed for feeding flue gases into the zone (58) and it is connected to the channel (10) for discharging flue gases from the cooled carbon black zone (60), the channel (9) is designed for feeding flue gases into the cooled carbon black zone (60) and it is connected by a flue to a chimney (63) to which a water supply pipe (64) ending with a sprinkler is also connected, and the channel (6) is used for pyrolysis gases and it is connected by a gas pipe to a combustion chamber (33) with a burner, on which a pyrolysis gas valve (31) is mounted, and on both sides of which a mineral oil separating condensation device consisting of a direct cooler (29) and a heat exchanger (24) is connected, and the combustion chamber (33) with a burner is directly connected to a boiler (34) which is connected on the one hand to the channel (8), for feeding hot gases into the pyrolysis furnace (2) and also into a contact economizer (42), and the contact economizer (42) is also connected to the device (47) for removing sulfur oxides from flue gases, which device (47) is in turn connected to the chimney (63), there is also designed an air humidifier (40) connected to the first fan (39), to the burner-with-burner combustion chamber (33), and to the contact economizer (42), the air-blowing zone (61) is connected to a second air fan (15) by means of an air supply channel (11), and on the other hand the air-blowing zone (61) is also connected to the channel (57) designed for air discharge, and the channel (57) is in turn connected to the chimney (63).

3. The device for the pyrolysis of whole tyres according to claim 2 (carrying out the method according to claims 1 and 2), characterised in that said trolleys (1) have a profile connected to a base plate (12) and to a vertical partition (50), and in that said vertical partition (50) is shaped according to the section of the pyrolysis furnace (2) and is sealed to the walls of the pyrolysis furnace by means of plates (51) connected to "hinges" and tensioned by tie-rods, each trolley (1) being designed with wheels (52) and the horizontal axis of the diameter of the tyres fitted into said trolley (1) being substantially perpendicular to the axis of the pyrolysis furnace (2), said tyres (49) being supported by stays (54), preferably made of expanded metal sheet, and being stabilized by brackets (53).