JPS5996189A - Polymer substance pyrolysis and apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to the cracking of polymeric materials by pyrolysis, and more particularly to a method and apparatus for producing fuel oil and other useful products from thermal polypropylene.

It has long been recognized that the production of unwanted polymeric substances as by-products in industrial processes is increasing and that there is a need for strategies to use them economically and commercially for the treatment of these substances. It is becoming recognized.

The heat content of most waste polymeric materials makes them all potentially usable as fuel. However, many high and intermediate molecular weight polymeric materials, such as atactic polypropylene, are semisolid at room temperature and difficult to feed and grind, which also makes them difficult to combust directly in conventional systems. It is not suitable for Various methods of thermally decomposing these waste polymeric materials into low molecular weight fragments to make them easier to handle and economically valuable for fuel oil and industrial feedstock materials are known in the prior art, such as in U.S. Pat. No. 3,829. , No. 558, No. 3,832゜151
No. 4,151,216.

A major problem with the known process is the accumulation of by-products, especially carbonaceous materials, on the heat transfer surfaces of the thermal reactor. The accumulation of these substances on the heat transfer surfaces limits their capacity and requires periodic shutdowns for batch-type, ie, furnace-by-furnace, operation or cleaning. The non-uniform heating characteristics of conventional furnaces promote the accumulation of carbonaceous materials,
This contributes to the increase of hot sporatra on the heat transfer surface along the path of the waste material to be pyrolyzed. Prior art approaches to this problem, such as low reaction temperatures, dispersion of accumulated carbon, and evacuation of the carbon-rich portion of the reactants, have sufficiently addressed this problem to create a commercially viable continuous process. Not resolved or removed.

In the present invention, the unnecessary polymeric material such as atactic polypropylene is preferably used at a temperature of 50 to 250 psi.
It is melted in a heated tank so that it can be pumped up at a pressure of g. This molten feedstock is pumped through a thermally insulated pipe into a reactor conduit, preferably two or more separate reactor tubes, and even more preferably a helically wound tube of predetermined dimensions. is,
Therefore, by heat or thermal decomposition, the polymer material is thermally decomposed in the absence of oxygen for a predetermined period of time to a substance having a lower molecular weight compared to the molecular weight of the parent molecule on the polymeric material. The reaction time is determined by the dimensions of the reactor tube and the rate of flow of feed material therethrough. The reactor tube and the feedstock therein are heated uniformly to a precise temperature by means of a fluidized bed. The pyrolyzed products are discharged from the reactor tube into a separation device, such as a flash distillation device, where the product polymeric materials are separated into groups substantially according to their molecular weights.

Approximately 427°C (80°C) for atactic polypropylene
The reaction takes about 10 minutes at a temperature of
and 2-grade fuel oil and some light gaseous fuel, which can desirably be used as fuel for melting tanks and heating equipment for fluidized beds.

It is an object of the present invention to provide a method and apparatus for the pyrolysis of polymeric materials into low molecular weight materials and the production of uniform products by precisely controlling uniform temperatures and levels within the reactor tubes. be.

Another object of the present invention is to provide an efficient and economical method and apparatus for producing fuel oil from polymeric materials.

Another object of the invention is a method which is suitable for substantially continuous operation and in which one or more reactor tubes can be cleaned without affecting the operation of other tubes as described below. and equipment.

In view of the foregoing and other incidental purposes, the invention which is intended for patent protection and which includes the structural features, parts, combinations thereof, and modes of operation illustrated below or in the accompanying drawings, or equivalents thereof, is hereby disclosed. will be explained in more detail and more fully below.

The accompanying drawings are a system for pyrolyzing atactic polypropylene constructed in accordance with the present invention, and a schematic process flow diagram of the main parts of the present invention. Certain appurtenances, valve equipment, gauges, heaters, agitators, pumps, etc. have been omitted from this drawing for clarity of the invention; It can be prepared using the following methods.

As shown, the apparatus of the invention includes a heated melt tank 10 connected to a pump by a conduit 12. The pump 1
4 discharges into a conduit 16, which is divided into separate tank feed tubes 18 and 18' communicating with each of the respective reactor tubes 20 and 20', each feed tube having a respective valve. 19 and 19' are provided. The reactor conduits or tubes 20 and 20' are arranged in a fluidized bed furnace 22 with the following passages, preferably helical coils. The fluidized bed is placed in an enclosing device 2 with a distribution plate 26 at the bottom.
4, and the distribution plate divides the enclosure # into a lower filling chamber 28 and an upper fill area 30. A burner device 32 is provided in the lower plenum 28 for passing heated air upwardly through the distribution plate 26 into the fluidized bed section 30 . A fluidized bed medium of solid particles is placed in the bed area 3o and becomes suspended in the hot gas stream coming upwardly through the distribution plate 26 into a fluidized material 33, which fluidized material 3
0 transfers heat to the reactor tubes 20 and 20' wrapped inside it. The fluidized air is sent to the surrounding device 24.
from the conduit 34 into a separator 36, preferably a cyclone, which separates the fluidized solids flowing with the exhaust gas or air and discharges the separated gas into the atmosphere. Discharge. The above reactor tubes 20 and 20
' is a conduit 37 to a separator 38, e.g. a flash distillation device.
and 37' to discharge the product. A conduit 42 connects from the bottom of the separator 38 to a cooler 44 and delivers the high molecular weight product to a first storage tank 46 .

A conduit 48 connects the separator 38 to the condenser arrangement 5°. The condenser device 5o comprises a first discharge conduit 52 for gaseous products of low molecular weight and a second discharge conduit 54 for liquid products of medium molecular weight, each conduit being connected to a suitable storage. equipment, such as a second storage tank 56;
It is connected to a third storage tank 57.

In a preferred embodiment of the invention, atactic polypropylene, i.e., a solid or semi-solid at room temperature and a partially crystalline material that constitutes a mixture of unwanted by-products in the commercial manufacturing process of polypropylene, is thermally decomposed. It is converted into fuel oil and other useful substances. Typically, waste atactic polypropylene from a commercial polypropylene facility is collected in a dissolution tank 10 and transferred to a reactor tube 2 at a pressure of 50 to 250 psig.
It is typically heated to about 204°C (about 400"F) until it is sufficiently liquid to be pumped to 0 and 20'.

The reactor tube is heated to a sufficient temperature (approximately 427°C (below 800°C) for a sufficient time) to break the carbon-carbon bonds in the waste material and produce the desired product.

The product, typically 90 gw as a liquid and 10 gw as a gaseous fuel at about 25° C., is discharged from the reactor tube to a separator 38 where the liquid is a heavy (high viscosity) ) part, light (low viscosity) part and remaining gas mixture, the mixture is sent to a condenser device where the light (low viscosity) part is condensed and the remaining gas is discharged into a suitable storage container. Ru. This gas is preferably used as fuel for the melting tank and heating equipment for the fluidized bed.

The extremely precise and uniform heating provided by the fluidized bed reduces the amount of carbonaceous deposits that form within the reactor tubes over long periods of operation; Collecting impedes its function and reduces the thermal conductivity from the fluidized bed to the material within the tube.

Reactor tubes 20 and 20' are supplied with nitrogen and blanks separately, apart from the polymeric material, so that they can be cauterized, ie, cleaned, without affecting the processes in the other reactor tubes. , continuous operations can be performed.

To elaborate on this example, the ablation operation is carried out in the apparatus described above by interrupting the flow of atactic polypropylene to selected reactor tubes 20 in the operating apparatus, which operation is carried out by closing the supply valve 19. , open the adjustable purge valve 00 and allow inert gas, preferably nitrogen, to flow in to displace any feed material and/or pyrolysis material in the tube 20 and clean that portion of the apparatus. do. Thereafter, the product discharge valve (52
is closed to interrupt the flow of product or purified gas to the separator 38, and the purification discharge valve 64 is opened to allow the nitrogen purification gas to be discharged to the atmosphere or to the pyrolyzed material prior to discharge into the feedstock. into the filling chamber of the fluidized bed furnace for combustion. An adjustable air inlet valve (56) is then opened to allow gaseous oxygen to flow into the reactor tube 20 to remove any carbonaceous deposits remaining in the vaginal tube after purging with nitrogen. The purge valve 60 for nitrogen inflow is closed at this point to enhance the combustion by increasing the available oxygen.The heat from this combustion brings the reactor tubes to a superheat temperature in conventional systems. However, in the present invention, the temperature of the reactor tubes is controlled at a safe level by a fluidized bed, which is heated by the heat of combustion of the carbonaceous deposits. Effectively removes excess heat generated and prevents damage due to overheating.

Once all of the carbonaceous material in the tube 20 has been cauterized as described above, the air inlet valve 66 is closed and the reactor tube 20 is flushed with nitrogen until all oxygen has been exhausted. The purge exhaust valve 64 and nitrogen inlet valve 60 are then closed and the supply valve 19 is reopened to allow polymeric material to flow into the tube. Finally, the product discharge valve 62 is opened to return the tube 20 to full operation.

Following the above, the other reactor tube 20' is tube 2
0 is affected by the cauterization operation and is in a state where it can perform its original operation. When the reactor tube 20 returns to the pyrolysis operation, next, the other reactor tube 20' operates the valve to the reactor tube 20' without affecting the reactor tube 2o, and performs the cauterization operation in the same manner. I do. According to the invention, the apparatus preferably comprises a plurality of reactor tubes, preferably from 2 to 6, of which one or more tubes can be simultaneously subjected to an ablation purification operation by a modification of the above method.

From the above description, it can be seen that the above device is provided having each of the features of the above-mentioned sequence and advantages, and that changes in its form and proportions can be made without departing from its essence or losing its advantages. , it is possible to vary the detailed construction and arrangement of parts.

In order to comply with the provisions of the law, some of the structural features of the present invention have been described in detail and some parts have been described in outline, but the present invention is not limited to the above-mentioned characteristic parts. The device and structure disclosed in the above include various aspects for actually carrying out the invention, and the present invention covers such aspects, modifications, and variations within the scope of legitimate and valid rights disclosed in the claims. It must be understood that rights are claimed for all.

[Brief explanation of drawings]

The drawing is a schematic process diagram of the main parts of an apparatus for pyrolysis of atactic polypropylene constructed according to the present invention. Explanation of symbols of main parts 10... Heating melting tank 12... Conduit 14...
Pump 16...Conduit 18.18'...Separation supply pipe 19.19'...Valve 20, 2
0'...Reactor tube 22...Fluidized bed furnace 24...
Surrounding device 26...Distribution plate 28...Lower filling chamber 30...Upper fluidized bed area 32...Burner device 33...Fluidized substance 34...Conduit
36...Separator 44...Cooler 46.
・First storage tank 50... Condenser device 56.
...Second storage tank 57 ...Third storage tank 6
0. l'...Purification illusion 62...Discharge valve
64... Purification and discharge valve 66. 66'... Inflow valve procedure amendment April 4, 1980 Kazuo Wakasugi, Commissioner of the Patent Office 1, Indication of examples, Patent Application No. 1983-3595 2, Invention Name: Method and apparatus for thermal decomposition of polymeric substances 3; Relationship with person making the amendment A'4 'B+ i'i'l Applicant's address
New Brunswick, New Jersey, United States of America 4Nomares 1-1-221 Name Pro-Tyne Coalition Representative Harbor 1-Kenneth Staffin 11.1 Register American Congregation [I, 14, Agent Tokyo] Port] Shinbashi 1 'T-['j 18ffl 19
No. Kimura A) Hitogaki Hill 6th floor procedural amendment April 21, 1980 Kazuo Wakasugi, Commissioner of the Patent Office 1. Indication of the case: Japanese Patent Application No. 58-3595 2. Title of the invention: Thermal decomposition of polymeric substances. Method and apparatus 3, person making the correction, a9 relationship Special ¥ [Applicant address: New Brunswick, New Jersey, United States of America, Summersella 1~S1~Lee 1~
221 Name Pro Tyne Cooperation Representative Harbor 1-Kenneth Staffin Nationality United States 4, Agent

Claims (1)

[Claims]] Passing a polymeric material through a reactor tube placed in a fluidized bed, which exposes the polymeric material to a pyrolysis temperature that causes thermal decomposition of the polymeric material to lower molecular weight materials. A method of pyrolysis of a polymeric material comprising the steps 3.2, comprising the step of dissolving said polymeric material prior to passing said polymeric material through said reactor tube. The method described in paragraph 1. 3. Claims 1 or 2 further comprising the step of separating by size the polymeric material treated in the reactor tube as it exits the reactor tube.
The method described in section. 4. exposing the deposits of carbonaceous material trapped in the reactor tubes to oxygen at a temperature sufficient to cause the materials to burn; 2. The method of claim 1, including the step of conducting at least a portion of the heat of combustion into the fluidized bed to prevent overheating of the tune. 5. A plurality of the reactor tubes are provided, and the purification step is performed in at least one reactor tube while the polymer material is being thermally decomposed in at least one reactor tube, and the purification step is performed in at least one other reactor tube to reduce the 5. A method according to claim 4, wherein the molecular substance is produced continuously in an apparatus. 6. The method of claim 5, including the step of purging the reactor tube with all inert gas before exposing the carbonaceous material deposit to oxygen in the reactor tube. 7. The method of claim 6, further comprising the step of purifying the reactor tube with an inert gas after burning the carbonaceous material deposit within the reactor tube. 8. The method of claim 6, wherein the inert gas is nitrogen. 9. The method according to claim 7, wherein the inert gas is nitrogen. 10. Claims 4 and 5, wherein the oxygen is contained in the air introduced into the reactor tube. , 6, 7, 8 or 9. 11 heating the carbonaceous material in the reactor tube to a temperature at which the carbonaceous material deposit burns when exposed to oxygen; introducing oxygen to the carbonaceous material deposit to cause combustion of the carbonaceous material; Bathing: Cleaning deposits of carbonaceous material from the surface of a device that exchanges heat with a fluidized bed, consisting of the step of conducting a portion of the temperature from the combustion into the fluidized bed to prevent overheating of one surface of the reactor tube. how to. 12 a fluidized bed used at a pyrolysis temperature, comprising at least one or more reactor tubes having an artificial opening and an outlet opening; 1. An apparatus for pyrolyzing a polymeric material, comprising: moving the polymeric material, subjecting the polymeric material to a pyrolytic condition, and pyrolyzing the polymeric material to lower molecular weight materials. 13. The apparatus of claim 12 including a heated tank for dissolving and discharging said polymeric material into said reactor tube. 14. The device of claim 13, wherein the device for moving the polymeric material is a pump device. 15. A plurality of said reactor tubes are provided, each of said reactors including a device for adjustably supplying polymeric material to said inlet opening independently of one another. , 13 or 14. 16. Apparatus for adjustably supplying an inert gas to the inlet opening of each of said reactor tubes; and apparatus for adjustably supplying an oxygen-containing gas to the inlet opening of said valley reactor tube. Apparatus according to scope 15. 17. Claim 12, further comprising a separation device for receiving and separating the pyrolyzed polymeric material discharged from the outlet opening of the reactor tube into fractions.
The device according to item 13 or 14. 18. The apparatus of claim 17, wherein the separation apparatus is a flash distillation apparatus. 19. The apparatus of claim 15 including a separator for receiving and separating the pyrolyzed polymeric material discharged from the opening of the reactor tube into fractions. 20. The apparatus according to claim 19, wherein the separation apparatus is a flash distillation apparatus.