Method for deploymerising residues containing hydrocarbons and device for carrying out said method

Abstract

The invention relates to a method for depolymerising raw materials containing hydrocarbons, such as residues in a continuous process. To achieve a uniform operation using a comparatively simple technique, the raw material, which has been pre-heated to a liquid or pulpy consistency, is continuously injected under pressure into a reactor ( 4 ), which has been heated to a decomposition temperature and a gaseous fraction is continuously withdrawn from the reactor for further processing, whilst a bottom fraction is continuously removed or removed at intervals. The raw material is preferably pre-heated, liquefied and injected by an injection pump or exterior screw. A high degree of availability is guaranteed in conjunction with a mixer or doctor head, which cyclically removes deposits on the interior walls of the reactor.

1 . Method for the depolymerization of hydrocarbon-containing raw materials, such as residues, in a continuously operating process, characterized in that the raw material is continuously injected under pressure in a preheated state and with a liquid or slurry-like consistency into a reactor heated to the cracking temperature and a gaseous fraction is continuously drawn out of the reactor for further processing and also a sump fraction is transferred outward from the reactor continuously or at intervals. 
   
   
       2 . Method according to  claim 1 , characterized in that the injection is performed under pressure by means of an injection pump or extruder screw, especially one like those known from plastic injection molding. 
   
   
       3 . Method according to  claim 1 , characterized in that the raw material in an injection pump or extruder screw is exposed to a pressure between 100 and 1 bar, preferably between 100 and 2 bar. 
   
   
       4 . Method according to  claim 1 , characterized in that the preheating is performed to a temperature above approximately 100° C., preferably above approximately 250° C. 
   
   
       5 . Method according to  claim 1 , characterized in that the preheating is performed in two stages, wherein, in a first stage, raw material reaches a temperature of approximately 100-150° C. under kneading and compression for removing gases and interstitial spaces, and in a second stage, preheating to approximately 200-300° C. is performed while simultaneously building up the pressure. 
   
   
       6 . Method according to  claim 5 , characterized in that a pressure expansion stage for separating gases, such as water vapor, is initially performed in connection with the first preheating stage. 
   
   
       7 . Method according to  claim 1 , characterized in that the raw material contains at least one plastic. 
   
   
       8 . Method according to  claim 1 , characterized in that the raw material contains at least one oil. 
   
   
       9 . Method according to  claim 1 , characterized in that heated wall zones of the reactor are cooled through stirring of the reactor contents close to the wall. 
   
   
       10 . Method according to  claim 1 , characterized in that the reactor temperature at the inner wall is kept at a temperature between 300° C. and 460° C., preferably between 340° C. and 440° C., and very especially preferred between 390° C. and 420° C., during the depolymerization. 
   
   
       11 . Method according to  claim 1 , characterized in that the raw material is fed at a distance from the reactor wall, especially into a central region of the reactor, to the fluid subject to the depolymerization. 
   
   
       12 . Method according to  claim 1 , characterized in that heated wall zones of the reactor are cleaned of any caking deposits cyclically over their entire surface during the depolymerization by means of a scraper adapted in shape to the wall contour. 
   
   
       13 . Method according to  claim 12 , characterized in that the scraper is subject to self-cleaning from time to time. 
   
   
       14 . Method according to  claim 1 , characterized in that the reactor is replaced by separating it from its cover and/or from further processing stages, for example, from a distillation column, and lowering it as well as moving it laterally or pivoting it if necessary. 
   
   
       15 . Device for the depolymerization of hydrocarbon-containing raw materials, such as residues, in a continuously operating process, comprising a heated cracking reactor, a device for preheating liquid, paste-like, and/or solid hydrocarbon-containing raw materials, a device for feeding the raw material with a liquid or slurry-like consistency into the reactor, a distillation column connected fluidly to a gas space of the reactor, a reactor sump for the outward transfer of sump material, and also a scraping device for the cyclical cleaning of at least the liquid-covered reactor inner walls during the depolymerization process. 
   
   
       16 . Device according to  claim 15 , characterized by a pressure injection device, such as an injection pump or an extruder screw, for preheated raw material, which is connected as a feed-in device to the input of the cracking reactor for injecting the preheated raw material under pressure into the cracking reactor. 
   
   
       17 . Device according to  claim 15 , characterized by a pot-shaped reactor. 
   
   
       18 . Device according to  claim 17 , characterized in that the reactor has a rotationally symmetric inner contour. 
   
   
       19 . Device according to  claim 18 , characterized in that the reactor has an approximately crowned inner contour. 
   
   
       20 . Device according to  claim 15 , characterized by a multiblade, rotating/rotatable mixer or stirrer with arms and blades. 
   
   
       21 . Device according to  claim 20 , characterized in that the blades consist at least partially of temperature-resistant ceramic or graphite material. 
   
   
       22 . Device according to  claim 20 , characterized in that the blades essentially duplicate the inner wall contour of the reactor. 
   
   
       23 . Device according to  claim 15 , characterized in that scraping elements of the scraping device essentially duplicate the inner wall contour of the reactor. 
   
   
       24 . Device according to  claim 23 , characterized in that the scraping device has a scraping head, which is composed of a rotary shaft and at least two blades, which have scraping elements. 
   
   
       25 . Device according to  claim 24 , characterized in that the scraping head contacts the inner wall of the reactor with its own weight and/or by means of a pressure force maintained by means of the rotary shaft. 
   
   
       26 . Device according to  claim 25 , characterized in that the rotary shaft has an especially pluggable rotary drive connection, which permits movement of the scraping head with increasing wear of the scraping elements for equalizing the wear play. 
   
   
       27 . Device according to  claim 23 , characterized in that the blades of the scraping head have a holder for a scraping element formed as a wear part. 
   
   
       28 . Device according to  claim 27 , characterized by a separating layer for preventing contact between the holder and the scraping element on the blades. 
   
   
       29 . Device according to  claim 23 , characterized by a wear detection device for the scraping elements. 
   
   
       30 . Device according to  claim 29 , characterized by an electrical circuit that detects an electrically conductive bridge between a scraping element and a holder or attachment of the scraping element as a signal for an advanced state of wear of the scraping element. 
   
   
       31 . Device according to  claim 24 , characterized by a self-cleaning element of the scraping head for occasional cleaning of the scraping element, especially during the continuous depolymerization operation. 
   
   
       32 . Device according to  claim 31 , characterized in that the self-cleaning element moves relative to the scraping element under mutual contact on the scraping element. 
   
   
       33 . Device according to  claim 31 , characterized in that the self-cleaning element can be displaced along the scraping element by means of a drive element guided on or in the rotary shaft. 
   
   
       34 . Device according to  claim 32 , characterized by a contour of a scraping edge of the self-cleaning element corresponding essentially to the contour of the scraping elements. 
   
   
       35 . Device according to  claim 31 , characterized in that the self-cleaning element is arranged on the front side of the scraping element in the direction of movement. 
   
   
       36 . Device according to  claim 31 , characterized by a self-cleaning head that can move along the scraping edge of the scraping element. 
   
   
       37 . Device according to  claim 36 , characterized in that the self-cleaning head can be moved along the scraping element by means of an elastic drive element guided along the scraping element. 
   
   
       38 . Device according to  claim 15 , characterized in that the reactor is preferably separated together with its heater from a reactor cover, can be separated from the distillation column by lowering, and can be exchanged for a new or overhauled reactor. 
   
   
       39 . Device according to  claim 38 , characterized in that the reactor can be set deeply in a heating jacket. 
   
   
       40 . Device according to  claim 38 , characterized in that the reactor has flow guiding elements on its outer wall to intensify the heat contact between the reactor and the fluid cooling or heating the reactor outer wall. 
   
   
       41 . Device according to  claim 40 , characterized in that the flow-guiding elements create a circulating fluid flow at least on a partial circumferential surface of the reactor.