DE1643811A1 - Process and system for carrying out pyrolysis reactions - Google Patents

Description

DR.-INQ. ULRICH GARLIC PATENTANWALT β Frankfurt / Main.ι, October 2, 1967 POST CHECK ACCOUNTFRANKfURTM ₃₄₂₅ KOHHORNSHOFWEa TO.

DRESDNER BANK, FRANKFURT / M. 553 7OS TELEPHONE: 5902O7 T? ",, P

TELEGRAM: KNOPAT

CHEPOS Zavody chemickeho a potravinarskeho strojirenstvi, oborovy podnik, Brno (OSSR)

Procedure and system for the implementation of Pyrolysis reactions

The invention relates to a process of .Pyrolysereaktion ¹ *, in particular for the production of unsaturated hydrocarbons, such as ethylene, propylene and acetylene, by splitting the hydrocarbon raw material and a system for carrying out this process.

Pyrolysis processes are known, the flue gases as heat transfer media use. Up to now, the flue gases have either been generated separately or directly in the pyrolysis equipment. Will the Flue gases generated directly, the system for splitting the hydrocarbons consists of a burner that connects directly to the actual Pyrolysis apparatus in which the flue gas is produced, is connected, further from a mixing device in which the Flue gas is mixed with the raw material, and the actual Reaction and cooling room. ■

The reaction space usually has a wall made of impermeable material. The flue gas provides all the heat that zub Warming up the raw materials and the actual course of the reaction

is
necessary is. Since with / it is necessary that the reaction temperature in

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as short a time as possible. So is .prevented that the reactions take place at lower temperatures and one require longer response time. As a result of the endothermic reactions there is a decrease in temperature in the direction of the flow of the reaction mixture, while but the end result the pyrolysis reaction favorably influenced by a rising temperature will. The working period is shortened because soot and substances similar to kois build up on the walls of the reaction chamber. ·

This should put a stop to these undesirable observations that the & eaction runs in the interior of a through pipe, through the wall of which the flue gas or another heat transfer medium, for example oxygen, is introduced. When oxygen is used, its reaction with the fission raw material generates the necessary warmth. This prevents the build-up of soot and coke and an apparent increase in temperature is also evident achieved; however, the slow heating of the fission raw material has a disadvantageous effect on the heat of reaction, with the reaction time increasing extended at low temperature. With regard to

the necessary amount of heat would be required for a very long time To use through pipes, possibly a through point, which is very difficult to produce. In addition, part of the The interior of these tubes has a preheating space, but no reaction space. Finally, if flue gas to secure the necessary Amount of heat through introduction through the wall of the passage tube is used, losses are caused by radiation into the environment.

It has already been suggested to add oxygen to the reaction mixture to be introduced through a porous element in front of the reaction space. Under these conditions, however, the course is not optimal the temperatures guaranteed, since along the reaction path no heat is supplied to supplement the heat losses that arise under the influence of endothermic reactions. Another disadvantage of this solution is that approaches of soot or the like on the inside of the reaction chamber. develop.

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For the splitting of hydrocarbons, a furnace is known which Combines the burner, the mixing system and the reaction chamber in one system. This system consists of a porous body in the form of a cylindrical jacket, which is provided with axial channels for the introduction of methane, while the oxygen is introduced radially. The fission raw material is introduced into the interior of the permeable cylindrical jacket in the axial direction. Burning with oxygen occurs here in the upper class the inside of the cylindrical shell. This system makes great demands on the material in terms of steep temperature gradient in the radial cross-section of the permeable Coat.

Next were different systems, for example generators for "Generation of hydrogen gas, used the permeable walls to deliver part of the production gases to the next Have combustion outside or inside in the reaction chamber. the The resulting heat is used for indirect heating of the reaction space used, so that the amount of heat that is supplied to the reaction space is limited by the heat load on the wall, which mediates the heat exchange. Systems of this type, however, can neither'the necessary increase in temperature in the reaction space secure in the direction of the axial flow, nor prevent the build-up of soot or the like on the inside of the reactor walls.

Finally, a system is known which consists of a ptrous tube, in which the reacting constituents on both sides of its jacket, which is provided with a catalyst . are fed. The reaction occurs in this case as a result of the diffusion of the constituents from both sides into the pores of the body of the porous tube. However, this system cannot be used for pyrolysis reactions, since it does not allow the supply of heat, and in addition the pores of the porous tube would be clogged by reaction products. The reaction occurs in ₍ . The part of the pipe and not in the interior of the pipe body.

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The invention has for its object to be compared with

the "known procedures are substantially functional and wirtanzugeben ^ö

more economical manufacturing process / in which at the same time Extension of the working period, the heat losses are reduced and the yield increased.

According to the invention, this object is described in the introduction The method achieved in that from a larger part of the total amount of oxygen or oxygen-containing gas for the pyrolysis reactions are generated by combustion with flammable gases * or vapors, hot smoke gases, whereby the cracked raw material through direct mixing with the flue gases to the pyrolysis reactions the remaining part of the oxygen is preserved or oxygen-containing gas is introduced through the porous wall with excess pressure into the reaction space and in this with the Stream of the mixture reacts, which was created by the mixing of the hot flue gases with the fission raw material.

Due to the porous wall of the reaction space, only a small part of the oxygen or the oxygen-containing one is in this space Gas supplied, while at the same time the greater part of the oxygen or oxygen-containing gas to the upstream Burner is supplied. This solution basically allows

) In addition, the reduction of the heat exchange surface in the reaction space. According to the invention you can therefore advantageously small Reaction chambers use instead of long porous tubular reactors that are difficult to manufacture.

The chamber-like reaction space is far better. exploited ^ as for example the reaction space of long, serpentine tubes. The reason for this is that most of the heat is direct the flue gases are fed from the burner to the mixer, which are instantly and intensively mixed with the raw material. The raw material is therefore heated to the reaction temperature as soon as it enters the reaction chamber. Through rapid bridging

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the low temperature will be a uniform starting temperature achieved and a possible course of undesirable reactions is prevented. Since the main part of the heat through the flowing flue gases is supplied axially, it is impossible that the permeability would be impaired, even if the flue gases were contaminated the porous wall of the reaction chamber gradually decreased. This eliminates the malfunctions in operation, which could occur if the flue gases were introduced through the wall surrounding the reaction space.

Another advantage of the invention is that the raw material is not heated up rapidly by flue gases to the initial reaction temperature of the pyrolysis, the value of which is given by the nature of the raw materials and the desired products, for example in the production of ethylene and propylene from gasoline about 750 ° -, but also that a sufficient amount of additional heat is supplied during the entire course of the reaction and in the entire contents of the reaction chamber by introducing oxygen at overpressure through the porous wall of the reaction chamber and its subsequent combustion. By burning the oxygen that passes through the wall of the reaction chamber, only heat is generated that is necessary to compensate for the heat losses from endothermic reactions and possibly to regulate the rise in temperature. It has been shown that if, after rapid heating of the raw material by flue gases in the reaction chamber, no uneconomical temperature drop is to follow, it is necessary to combine this rapid heating with an oxygen supply to the extent that the heat generated by burning part of the Products, in particular from hydrogen, methane and hydrocarbons, result in a maintenance or gradual increase in the temperature in the reaction space. This results in generally more favorable thermodynamic and natural conditions for the course of the pyrolysis reaction, which are ultimately expressed in an increased yield. The reaction temperatures can thus advantageously be brought into overflow with the course of the gradual formation of the reaction products, which are subject to further pyrolysis reactions, and also with the reaction time, ie for the

eventual formation of the unsaturated products, i.e. ethylene, Acetylene, propylene, or the like, is optimal.

Because the oxygen is supplied according to the invention through the entire surface of the reaction chamber, ädne is achieved continuous temperature change is achieved without any sudden changes in temperature, which ensures the steady operation of the - ^ eaktors could endanger. With this measure, a more uniform product is achieved at the same time and the losses as a result undesirable reactions that occur under other undesirable reaction conditions are reduced. Important is Finally, that the workflow according to the invention a precise setting of the initial reaction temperature and also the Allows maintaining the desired temperatures during the reaction in the reaction chamber. This adherence to the! '.' Optimal

a temperature in the reaction space is set by / very simple manipulation made, namely by changing the amount of de »supplied Oxygen or oxygen-containing gas.

Another advantage of the invention is that the heat is dissipated through the porous wall of the reaction spaces S is not lost, but is absorbed by the oxygen again, which in passing through the entire surface of the porous wall into the reaction chamber. This increases the economic efficiency of the heat balance of the pyrolysis system according to the invention. Since the porous wall of the. Reaction chamber is cooled by the oxygen flowing through, materials can also be used to produce the porous wall of the reaction chamber which do not have high resistance to heat, for example bronze.

By introducing oxygen or oxygen-containing gases through the porous wall of the reaction chamber, a build-up of soot or the like on the inside of the wall of the reaction chamber is prevented, because the oxygen that penetrates through the pores cleans them mechanically and durably chemistry oh · reaction a deposition of organic substances on the inner surface of the reaction wall is prevented.

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The system according to the invention can be implemented in various variations. For example, it is advantageous if the system has a burner which opens into a mixer, which in turn is attached axially at the entry into the reaction chamber which has a porous wall disposed in an outer shell, with between the outer shell and an entry space for the oxygen or the oxygen-containing gas is provided on the outer wall of the reaction chamber. This solution is mainly because of its simple design and manufacture and because of the relatively small dimensions advantageous in relation to the high performance achieved.

The reaction chamber does not always have to have a circular cross section to have. It is possible to have a polygonal design with porous walls, but you should always use the The cost-effectiveness of the production of the system must be taken into account. Ducht replacement of the regular, circular cross-section of the Reaction space through a porous, frustoconical body, on the one hand, can have a more favorable influence on the temperature curve by increasing the supply of oxygen into a reaction chamber with a gradually widened cross-section ^ on the other hand a more uniform velocity of the flow of the reactants in the reactor can be achieved. The volume of the reacting substances grows namely when passing through the reactor due to the pyrolysis and oxidation reactions and as a result the rising temperature.

All systems according to the invention are due to the combination the axial heat supply through flue gases and the heat that 'effe in the combustion of the reaction mixture with oxygen which is introduced through the permeable wall of the reaction tubes is characterized by a high operating elasticity. One and the same system can be used simply by changing the Reaction conditions, for example by changing the amount of reactants and the temperature, the pyrolysis of the most varied Perform types of products. So you can, for example

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a mixture of ethylene and propylene, or a mixture of ethylene and acetylene, optionally also synthesis gases. This makes it possible to quickly change the type of production depending on the demand without changing any further investments in the pyrolysis plant.

The porous walls of the reaction chamber can, for example, be made from ceramic, metallic and combinations of ceramic and. metallic materials. One can go through depending on the the type of heat balance given conditions and according to the

of products, to ^ö ^ *

Type / whose generation the system is intended to be used, also with advantage

J) Use stainless steel or bronze materials. Your choice is determined by the desired strength of the porous wall and by the possibility of the simplest processing required by the type of manufacturing process. Balls with a uniform permeability of the porous wall formed from them are particularly advantageous. A permeable wall made of staple fiber of the materials mentioned is also very cheap.

The invention is illustrated below with the aid of one in FIG Embodiment described.

. The pyrolysis system consists of a burner. 1, a mixer 2 ™ and the actual reactor, which consists of an outer cylindrical There is jacket 5, in which the porous body 4 is inserted coaxially, for example a cylindrical body 4 with a reaction chamber 5, which opens into a cooler 6 with an outlet nozzle 7. The burner 1 is provided with an inlet port 8 for oxygen, as well as with an inlet nozzle 9 for a fuel gas and finally an inlet nozzle 10 for water vapor. On mixer 2 is an inlet nozzle 11 for the cleavage raw material, for example Gasoline, arranged. On the outer cylindrical jacket 3 there is an inlet connection 12 for oxygen. The cooler 6 has an inlet nozzle 13 for the cooling medium.

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The fuel gas, for example hydrogen or hydrogen-rich gas, is introduced into the burner 1 through the inlet connection 8 was, with the help of the inlet clip 8 supplied Burned oxygen. With the water vapor supplied through the inlet port 10, the temperature of the resulting Breath gases regulated. Hot breath gases "mix in the Mixer 2 with the fission raw material, which through the inlet seats 11 was fed. This leads to rapid warming of the Rhstoffes to the initial reaction temperature. The reaction mixture enters directly into the actual reaction chamber 5, where it is subjected to pyrolysis, the Heat, which is necessary for the reaction and for maintaining the correct course of the reaction, by burning a part of the reaction mixture obtained with oxygen, is obtained by the entry mare 12 under excess pressure through the wall of the porous Body 4 is introduced through into the reaction chamber 5. On the one hand, the pores of the porous body 4 are cleaned, on the other hand, the heat that escapes from the reaction chamber 5 through the wall of the porous body is returned to the reaction chamber 5 returned.

The reaction products that emerge from the reaction chamber 5 are cooled in the cooler 6 with a cooling medium, for example water vapor, water or hydrocarbons, which is introduced through the inlet connection 13, leave through the Outlet nozzle 7 the pyrolysis system.

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Claims (4)

- ίο - claims: 1. Process of pyrolysis reactions, in particular addition generation of unsaturated hydrocarbons, such as ethylene, propylene, acetylene, by splitting the hydrocarbon raw material, thereby marked that from a larger part of the total amount of oxygen or oxygen-containing gas for the Pyrolysis reactions are generated by combustion with flammable gases or vapors, hot flue gases, with the fission raw material is led to the pyrolysis reactions by direct mixing with the flue gases, while the remaining part of the Oxygen or oxygen-containing gas is introduced through the porous wall with excess pressure into the reaction space and in this reacts with the flow of the mixture that was created by the mixing of the hot flue gases with the fission raw material . 2. Plant for carrying out the method according to claim 1, characterized by a burner (1) which opens into a * mixer (2) which is attached axially at the entry into a reaction space (5), which is through a porous body (4 is) formed with, for example, circular cross-section, with an inlet space for the oxygen or the oxygen-containing gas is arranged between the outer casing (3) and the outer wall of the porous body ¹ (4). 3. Plant according to claim 2, characterized in that the reaction space (5) is formed by a porous body which has the shape of a truncated cone, whose base is arranged on the exit side of the reaction products. 4. Plant · according to claim 2 and 3, characterized in that the porous body (4) made of staple fiber or balls made of stainless steel, Hickel or Bronse. 109811/2136