WO2002068563A2

WO2002068563A2 - Method and device for the treatment of material containing carbon

Info

Publication number: WO2002068563A2
Application number: PCT/CH2002/000109
Authority: WO
Inventors: Alvaro De Oliveira Prado
Original assignee: Alvaro De Oliveira Prado
Priority date: 2001-02-25
Filing date: 2002-02-25
Publication date: 2002-09-06
Also published as: CH696585A5; AU2002231553A1; WO2002068563A3; BR0204343A

Abstract

The invention relates to a method and a device for the treatment of material containing carbon in a vertical shaft kiln. According to the invention, the material to be treated descends vertically, is subjected to various treatments and is subsequently withdrawn at the lower end of the kiln. The material descending in the chamber is subjected to a plurality of continuous, successive temperature and time-based treatment stages, until the treatment of said material is complete. The material is then cooled and finally withdrawn.

Description

Method and device for the treatment of carbonaceous material

The present invention relates to a method and an apparatus for the treatment of carbon-containing material in a vertical chamber shaft furnace, in which the material to be treated sinks vertically and is subjected to various treatments and finally discharged at the lower end of the furnace.

In the treatment of carbonaceous material and in particular in the carbonization of coke and / or the refinement of coke of inferior quality, there are major problems with regard to the consistent, homogeneous quality of the treated material, the abrasion during the treatment and thus the uniformity of the particle size of the treated good. This is particularly due to the difficulties in monitoring and controlling treatment during the procedure. The most commonly used method for the treatment of carbon-containing material today in this context and in particular for calcination is the rotary kiln method with a more or less inclined furnace axis of rotation between the end of the furnace feed and discharge. The heat of combustion of the gases and volatile substances from the carbon-containing material is constantly supplied to the material while it is being conveyed through the furnace.

Adequate heating is the biggest problem here, because the calcination is an endothermic process and any noteworthy combustion of the carbon-containing good itself must be avoided. The difficulties with such a heating control are impressively described in US 3,888,621.

In addition to the expenditure of large and heavy equipment material in the rotary kilns, there is another problem that roasted goods are produced with an uneven consistency and that due to the uncontrollable movements and the associated abrasion during the passage of the goods through the oven, a lot of dust and breakage occurs at the discharge end.

In order to avoid at least some of the problems that occur in rotary kilns, US Pat. No. 6,157,667 has proposed a method in which the carbon-containing material is calcined by means of electric current via an upper and a lower electrode. With this method, however, high thermal stresses can occur while the material sinks in the cylindrical vertical shaft. These thermal stresses arise from the electrical field built up between the electrodes. This creates calcined material of different homogeneity / quality according to the flow line of the sinking particles in the material. Therefore, this solution also proposes different discharge openings for the treated delte Gut vor, namely for desired and lower quality. These discharge openings and their control complicate the construction of this furnace, and it is confirmed that the end product according to this process is not of consistency and uniform quality. GB 1,055,857 describes a process for the continuous treatment with calcination of carbon-containing material in an essentially vertical system, in which the material is fed in peripherally in a rotary hearth and from there reaches a central discharge hopper. The goods are repeatedly knocked over on their way on the stove. This overturning causes the generation of significant amounts of dust and breakage in the treated material and leads to undesirable fire.

A similar device is described in EP 0159903, in which the material to be treated is overturned again and again in a vertical rotary hearth with the disadvantage of generating uncontrolled amounts of dust and breakage in the discharged material. EP 0098771 teaches a method and a device for producing coke in a shaft furnace, in which the heat is generated by electrical current between two opposing electrodes in the wall of the furnace. Here, as in US 6,157,667, the material is exposed to thermal stresses, which in turn leads to uneven quality of the material being treated. In addition, gases are recycled here, which is harmful to the environment. EP 0186170 describes a method and a device comprising a calcination step in a complex sequence of separate treatment steps. In this case, the calcination takes place in a vertical chamber shaft furnace, which is heated indirectly via the shaft walls. With this method, the generation of abrasion material is reduced. However, the homogeneous heating of the goods across the entire cross-section of the sinking goods is questionable, which in turn leads to irregular quality at the end of the discharge.

The object of the present invention is to overcome the disadvantages and difficulties of the known methods and devices shown above by means of a mechanically simple and thus also economical solution, in which the treated material has a high consistency and high, uniform quality.

To achieve this object, the invention proposes a method and a device of the type mentioned in the introduction, in which the material sinking during the treatment over a multitude of temperature / time zones, which continuously until the complete treatment of the goods in succession, exposed to direct heat, then cooled and discharged.

In a preferred embodiment of the invention, in particular in the calcination of carbon-containing material, at least three calcining steps are provided, namely with a first process step for evaporating water and extracting gas enclosed in the material, a second process step for breaking up / cracking hydrocarbon -Chains with subsequent distillation of volatile substances and their combustion and a third process step with heating and calcining the dry and degassed goods. According to the invention, it is advantageous if the sinking material is supplied with controlled air in order to maintain the embers and to control the combustion of the volatile substances and extracted gases from the carbon-containing material.

According to a further embodiment of the invention, which relates to the refinement of carbon-containing goods, such as Coke and / or roasted carbon-containing goods of poor quality, the application of carbon to the goods to be treated is carried out in at least three refinement steps, which follow one another continuously, and the treated goods are then cooled and discharged.

In this embodiment of the invention, the refinement steps include a first step in which the material is preheated, a second refinement step in which carbon is applied to the carbon-containing material after breaking / cracking hydrocarbon chains, a third refinement step with the partial combustion from the hydro-carbon gas supplied from the vertical chamber and a fourth step with drawing off, cooling, cleaning and recirculating the cracked gas together with the extracted gas from the partial combustion and with the addition of gas as a substitute for the cracked gas.

The particular advantages of the method and the device according to the invention are the simple construction, which can be set up anywhere and in particular at all processing locations, a considerable saving in complex systems, as a result of which the invention is also accessible to weaker economies, simple handling, avoidance of fertilization of dust and breakage as well as undesirable fire, no or only insignificant discharge of toxic, environmentally harmful gases and a uniform and controlled quality of the treated material.

Further details, advantages and features of the invention will become apparent from the following description in conjunction with the accompanying drawings. In these drawings are:

Fig. 1 is a schematic side view in section of a vertical chamber furnace according to the

Invention. FIG. 2 shows a schematic view similar to FIG. 1 of an embodiment of a vertical chamber shaft furnace according to the invention.

In the embodiment according to the invention shown in FIG. 1, the carbon-containing material to be treated is placed at the upper end of the vertical shaft furnace 10. The furnace 10 is preferably cylindrical in shape and has a feed hopper 1, a preheating stage 2, a stage 3 for the evaporation of water, a stage 4 in which the hydrocarbon chains begin to crack and move downwards, a stage 5, in which the cracked hydro-carbon chains transform into gas and move to the subsequent stage 6. In this level 6, the volatile substances from the goods are almost completely dissolved. This is followed by a cooling stage 7 and the discharge 8, where the treated material is loaded onto a conveyor belt 23.

It is essential for the method according to the invention that all of these stages follow one another continuously, and without any interrupting intermediate stage, so that a single column of material is formed over the entire height of the furnace 10. The device also has a chimney 12 with an afterburner 11 at a point below the feed bunker 1, in which the exhaust gases from the chimney 12 are completely burned.

At its lower end and above the cooling stage 7, the furnace 10 has a feed line 25 via which heat and air are supplied when the furnace is started up. Spread over its height, the furnace 10 has a multiplicity of air inlets 19, 20, 21 and 22 which are arranged along a suitable number of surface lines of the furnace 10 in such a way that air inlet rings are formed at different heights. Likewise, the furnace 10 has a multiplicity of temperature sensors 13, 14, 15, 16, 17 and 18, which are arranged in a suitable manner along surface lines of the furnace in such a way that temperature sensing rings are formed at different heights. When the furnace according to the invention is started up, it is completely charged from the feed bunker 1 via a feed throttle 26, so that an uninterrupted column of material to be treated forms over the entire height of the furnace 10. With closed air inlets 19 to 22, start-up heat and air are fed in via the feed line 25 in order to heat the material in stage 6 of the furnace 10. As soon as the desired heat is generated in stage 6, which is determined by the sensors 18, the air inlets 22, 21, 20 and 19 are opened in succession in such a way that the column of embers in the furnace 10 is controlled and homogeneous over the entire shaft diameter down to the stage 2 rises to the top. This creates a train across the chimney 12. The afterburner 11 in the chimney 12 burns all the gases and volatile substances drawn from the furnace and filters them if necessary.

After reaching the desired temperature in the individual stages 2 to 6, a discharge lock 24 is opened in order to gradually discharge goods from stage 7, to unload them onto the conveyor belt 23 in FIG. 8 and to load them from there onto suitable transport means 9. During the discharge of the material from stage 7, the entire glowing column of material in the furnace sinks down and new material is replenished via the feed lock 26.

After the furnace has started up, the feed line 25 is closed and the actual treatment process according to the invention begins.

Through a coordinated control of the air inlets 19 to 22, the material discharge via the discharge lock 24 and the material supply via the feed lock 26, the heat in the material column sinking in the furnace is controlled to the appropriate temperatures in the various stages 2 to 6. This is done via the temperature sensors 13 to 18, via which the temperature in the various stages 2 to 7 is permanently removed. Accordingly, air is supplied via the air inlets 19 to 22 in order to generate the desired heat in the individual stages. In the calcination, in which the material is treated according to the invention in at least three process steps, the first process step takes place in steps 2 and 3. The water and gas trapped in the good are extracted from the good at temperatures between 25 and 400 ° C. The preferred temperature according to the invention in the lower area of stage 3 is 340 ° C. The second procedural step immediately following the first takes place in stages 4 and 5. In this second process step, hydrocarbon chains are cracked at temperatures between 300 and 1100 ° C and the volatile substances are distilled and burned. The preferred temperature in the lower range of stage 5 is 980 ° C. The next immediately following process step takes place in stage 6. There, the dry and essentially gas-free material is heated and calcined at temperatures between 900 and 1500 ° C. The preferred temperature at the end of the calcination step is about 1300 ° C.

When coal is coked in accordance with the process according to the invention, an additional process step is carried out between the second and third process steps. In this additional process step, the material is plasticized at temperatures between 300 and 800 ° C and preferably at 550 ° C.

The total treatment time in the method according to the invention is between 14 and 20 hours depending on the nature of the material to be treated, which can be anything from light lignite to anthracite or green petroleum coke. For the process according to the invention, it is important to emphasize that the heat generated in the furnace is generated exclusively by the air supplied via inlets 19 to 22 and the combustion of volatile substances and gas, which was released in stages 2 to 6 by heating become.

This in turn means that no toxic or extraneous gases are required to maintain the embers that have been kindled and that no toxic gases escape from the furnace 10 through the chimney 12 into the environment. Any residual gases would be burned in the afterburner 11 and filtered out if necessary.

The embodiment of the invention shown in FIG. 2 is essentially about the refinement of coke and other low-quality carbon-containing goods. In this embodiment, the furnace 34 has essentially the same structure as the device according to FIG. 1, but also has additional equipment with slides 43, 44 and 45, which the individual process stages 28, 29, 30, 31 and 32 in demarcate the furnace 34 from each other.

Below the slide 43, a discharge line 35 leads the gas withdrawn from the furnace 34 to a heat exchanger 36, a gas purifier 37 and finally to a compressor 38, from which the gas is fed back to the furnace 34 via a feed line 41. In this feed line 41, hydrocarbon gas and a line 40 can be admixed with air via a line 39.

When operating the furnace according to the invention, the material is fed from a bunker 27 into the preheating stage 28 via a feed lock 42. In this stage 28, the good in a first finishing step at temperatures of 25 to 500 ° C and preferably preheated at 340 ° C.

After reaching this temperature and after a time necessary for the material to be treated, the material is entered into the immediately subsequent stage 29 via the slide 43. Here, the goods are heated in a second refinement step to release gas from the goods. Part of the gas released in this stage is drawn off, while the other part is cracked to carbon at temperatures between 500 and 1300 ° C and preferably at 1100 ° C. In the immediately following stage 30, the carbon is applied to the material before stage 31 is reached. In this stage 31, in a third upgrading step, hydrocarbon gas fed in via the feed line 41 is partially burned at temperatures above 1100 ° C. and preferably at 1300 ° C.

In a fourth refinement step, the gas which has not been cracked in stages 29 and 30 is drawn off via the discharge line 35, cooled in 36, cleaned in 37 and, via the compressor 38, is returned to the furnace 34 via the feed line 41 with the addition of gas via the line 39 to Replacement of the cracked gas is supplied.

After the complete treatment, the material passes through the slide 44 to cool down into the mare 32 and from there via the discharge lock 45 onto the conveyor belt 46, which unloads the material into suitable means of transport. The furnace 34 is started up similarly to the furnace 10 according to FIG. 1. As with this furnace 10, the furnace 34 has a large number of temperature sensors for monitoring the temperature in the individual stages 28 to 32, for controlling a feed lock 42 and the slide 43 to 45 and for the operation of the feedback circuit 35, 36, 37, 38, 39, 40 and 41. In both embodiments of the method according to the invention, the quality parameters of the treated goods are significantly improved, such as breaking strength, the reduction of oxidation by air and CO ₂ , the reduction in electrical resistance and the porosity and / or consistency. The construction of the furnace 10 and / or 34 in connection with the slowly sinking, glowing column of material and the constant direct heating continuously over all stages leads to avoidance of mechanical impact and abrasion of the material particles against one another and thus to avoid dust and Fracture. In addition, with the method according to the invention it is possible to have a precise relationship between the temperature of the goods and the amount of air to be supplied at each point to determine the height of the furnace and thus to control each individual process step individually and in context.

Due to the precise control of time and temperature during the calcination, no external heat is necessary to carry out the process. The heat in the pillar is even and controllable over the entire diameter of the shaft furnace. At the same time, it is possible to control the exact temperature for the controlled combustion of the volatile substances released, thus avoiding expensive equipment for heat recovery. In the refinement according to the invention, the critical phase of gas cracking can be precisely determined and controlled, as can the subsequent deposition of the carbon on the material.

The material treated according to the invention is particularly suitable for the production of coke electrodes from green petroleum coke. The invention is in no way limited to the described and illustrated embodiments. Rather, it encompasses all process variations that ultimately lead to the same or a similar result.

Claims

claims:

1. Method and device for the treatment of carbon-containing material in a vertical chamber furnace, in which the material to be treated sinks vertically and is subjected to various treatments and is finally discharged at the lower end of the furnace, characterized in that the material sinking in the vertical chamber is a large number from continuously successive temperature / time treatment steps to complete treatment of the goods, then cooling the goods and finally discharging them.

2. The method and device according to claim 1, in particular for the calcination of carbon-containing material, characterized by at least three calcining steps with a first method step for evaporating water and extracting gas enclosed in the material, a second method step for breaking up / cracking hydrocarbon. Chains with subsequent distillation of volatile substances and their combustion and a third process step for heating and calcining the dry and degassed goods.

3. The method and apparatus according to claim 2, characterized in that the descending goods for maintaining the embers and for controlling the combustion of the volatile substances and the extracted gases are supplied with controlled air.

4. The method and device according to one of claims 2 and / or 3, characterized in that the temperature in the first process step is between 25 and 400 ° C.

5. The method and device according to claim 4, characterized in that the temperature in the first process step is 340 ° C.

6. The method and device according to one of claims 2 and / or 3, characterized in that the temperature in the second process step is between 400 and 1100 ° C.

7. The method and device according to claim 6, characterized in that the temperature in the second process step is 980 ° C.

8. The method and device according to one of claims 2 and / or 3, characterized in that the temperature in the third process step is between 900 and 1500 ° C.

9. The method and device according to claim 8, characterized in that the temperature in the third process step is 1300 ° C.

10. The method and apparatus according to any one of the preceding claims, - characterized marked ^{'characterized} in that the time for the direct heating in the vertical chamber in a function of the quality control material to be treated is of the.

11. The method and device according to one of claims 1 to 10, characterized in that the rate of descent of the material in the vertical chamber is determined by the frequency of discharge of the treated material at the discharge end of the furnace.

12. The method and device according to one of claims 2 to 11, in particular for coal coking, characterized in that one carries out an additional process step between the second and third process step for plasticizing the sinking material in a temperature range between 300 and 800 ° C.

13. The method and device according to claim 12, characterized in that the temperature in this additional process step is 550 ° C.

14. The method and device according to claim 1, in particular for the refinement of carbon-containing material, comprising coke and carbon-containing material, characterized in that carbon is applied to the material to be treated in at least three processing steps, which follow each other continuously, that the material is then cooled and finally discharges the refined good.

15. The method and apparatus according to claim 14, characterized by a first finishing step in which the material is preheated, a second finishing step in which carbon is placed on the carbon-containing material after breaking up / cracking of hydro-

Applies carbon chains, and a third refining step with the partial combustion of hydrocarbon gas supplied from the vertical chamber and a fourth refining step with the extraction, cooling, cleaning and recycling of the uncracked gas together with the extracted gas from the partial combustion and with the addition of gas as a replacement for the cracked gas.

16. The method and device according to claim 15, characterized in that the temperature during the first finishing step is in the range between 25 and 500 ° C.

17. The method and device according to claim 16, characterized by a temperature of 340 ° C in the first finishing step.

18. The method and device according to claim 15, characterized in that the temperature during the second finishing step is in the range from 600 to 1300 ° C.

19. The method and device according to claim 18, marked by a temperature of 1100 ° C in the second finishing step.

20. The method and device according to claim 15, characterized in that the temperature in the third finishing step is above 1100 ° C. 21. The method and device according to claim 20, characterized by a temperature in the third finishing step of 1300 ° C. 22. Device for performing the method according to claim 1 and one of claims 2 to 14, characterized by a preferably cylindrical vertical chamber (10) with a feed end at the top and a discharge end at the bottom and a plurality of air inlets (19, 20,

21

22) distributed over different heights and along circumferential lines of the chamber (10).

23. The device according to claim 22, characterized by a cooling area (7) above a discharge lock (24) and a discharge (12) in the upper part of the chamber (10) for withdrawing the gases as a result of the combustion of gases and volatile substances from the carbon-containing material and for sucking in air through the air inlets (19, 20, 21, 22).

24. The device according to claim 23, characterized by an afterburner (11) in the fume cupboard (12) for burning possibly in the fume cupboard. (12) remaining toxic gases.

25. The device according to claim 22 characterized by temperature sensors (13, 14, 15, 16, 17, 18) which are arranged distributed over the height and along circumferential lines of the chamber (10).

26. Device for performing the method according to claim 1 and one of claims 15 to 21, characterized in that a preferably cylindrical vertical chamber (34) with a feed end above and a discharge end below and a plurality of slides (43, 44, 45) which separate different areas from each other via the height of the chamber (34), and a cooling area (32) above a discharge lock (45).

27. The device according to claim 26, characterized in that it has a return circuit (35, 41) which is connected to the chamber (34) in the region of the carbon application and the partial combustion (29, 30, 31) and a cooling (36 ), Cleaning (37) and a compressor (38) and supply lines for gas (39) and air (40).