Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
  • B01J19/08—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor
  • B01J19/087—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor employing electric or magnetic energy
  • B01J19/088—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor employing electric or magnetic energy giving rise to electric discharges
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
  • B01J19/08—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor
  • B01J19/12—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor employing electromagnetic waves
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
  • B01J19/24—Stationary reactors without moving elements inside
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C17/00—Preparation of halogenated hydrocarbons
  • C07C17/25—Preparation of halogenated hydrocarbons by splitting-off hydrogen halides from halogenated hydrocarbons
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C17/00—Preparation of halogenated hydrocarbons
  • C07C17/38—Separation; Purification; Stabilisation; Use of additives
  • C07C17/383—Separation; Purification; Stabilisation; Use of additives by distillation
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C21/00—Acyclic unsaturated compounds containing halogen atoms
  • C07C21/02—Acyclic unsaturated compounds containing halogen atoms containing carbon-to-carbon double bonds
  • C07C21/04—Chloro-alkenes
  • C07C21/06—Vinyl chloride
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
  • B01J2219/00049—Controlling or regulating processes
  • B01J2219/00051—Controlling the temperature
  • B01J2219/00157—Controlling the temperature by means of a burner
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
  • B01J2219/00049—Controlling or regulating processes
  • B01J2219/00191—Control algorithm
  • B01J2219/00222—Control algorithm taking actions
  • B01J2219/00227—Control algorithm taking actions modifying the operating conditions
  • B01J2219/0024—Control algorithm taking actions modifying the operating conditions other than of the reactor or heat exchange system
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
  • B01J2219/08—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor
  • B01J2219/0894—Processes carried out in the presence of a plasma
  • B01J2219/0896—Cold plasma

Definitions

• the present invention relates to a particularly economical process and a device suitable for the production of ethylenically unsaturated
• Halogen compounds by thermal cleavage of halogenated aliphatic hydrocarbons, in particular the production of vinyl chloride by thermal cleavage of 1, 2-dichloroethane.
• VCM vinyl chloride
• EDC 1,2-dichloroethane
• VCM is mainly produced by thermal cleavage of EDC, with the implementation of the equation
• reaction tube which in turn is arranged in a gas or oil fired furnace.
• the reaction is usually allowed to proceed to a conversion of 55-65%, based on the EDC used (in the following Feed-EDC).
• the temperature of the furnace reaction mixture leaving (the furnace outlet temperature) is about 480 - 520 0 C.
• the reaction is operated under pressure. Typical pressures at the inlet of the furnace amount to approx. 13-30 bar abs in today's processes.
• VCM is increasingly converted into secondary products such as acetylene and benzene, which in turn are precursors of coke deposits.
• the formation of coke deposits necessitates the shutdown and cleaning of the reactor at regular intervals.
• a conversion of 55%, based on the EDC used has proven to be particularly advantageous in practice.
• the reaction tube is arranged centrally as a coil constructed of vertically stacked horizontal tubes, wherein the coil can be made one or two-speed.
• the tubes can be arranged either in alignment or offset.
• the furnaces are heated by burners arranged in rows in the furnace walls.
• the heat transfer to the reaction tubes is predominantly by wall and gas radiation, but also convective by the resulting during heating by burner flue gas.
• the EDC cleavage is carried out in other furnace types, with different arrangement of the reaction tubes and the burner.
• the invention is in principle applicable to all furnace types and burner arrangements as well as to other ways of heating the reaction.
• a typical tube reactor used for EDC cleavage comprises a furnace and a reaction tube.
• a furnace fired with a primary energy source such as oil or gas, is divided into a so-called radiation zone and a convection zone.
• the heat required for the cleavage is transferred to the reaction tube mainly by radiation from the burner-heated furnace walls and the hot flue gas.
• the energy content of the hot, emerging from the radiation zone flue gases is used by convective heat transfer.
• the starting material of the cleavage reaction for example EDC
• EDC can be preheated, evaporated or superheated.
• the generation of water vapor and / or the preheating of combustion air is possible.
• liquid EDC is first preheated in the convection zone of the cracking furnace and then evaporated in a special evaporator outside the cracking furnace.
• the vaporous EDC is then in turn fed to the convection zone and superheated there, preferably in the shock tubes, whereby the cleavage reaction can already begin.
• the EDC enters the radiation zone, where the conversion to vinyl chloride and hydrogen chloride takes place.
• the burners are usually arranged on the longitudinal and front sides of the furnace in superimposed rows, wherein the aim is to achieve the most uniform distribution of heat radiation along the circumference of the reaction tubes by the type and arrangement of the burner.
• the part of the furnace in which the burners and the reaction tubes are arranged and in which the predominant conversion of the cleavage reaction takes place is called the radiation zone.
• the part of the furnace in which the burners and the reaction tubes are arranged and in which the predominant conversion of the cleavage reaction takes place is called the radiation zone.
• These rows of tubes are typically unaffected, and shield overlying internals, such as finned heat exchanger tubes of the convection zone, from the direct combustion chamber radiation largely from.
• these tube rows increase the thermal efficiency of the reaction zone through structurally optimized convective heat transfer.
• shock pipes or "shock zone” is common in technical terminology for these pipes or rows of pipes.
• reaction zone in the context of the invention, the reaction tubes located in the flow direction of the reaction gas following the shock zone, which are preferably arranged vertically aligned or offset one above the other, to understand.
• EDC electrospray
• the actual cleavage reaction takes place in the gaseous state of matter.
• the EDC is first preheated and then evaporated and possibly overheated.
• the vaporous EDC enters the reactor, where it is usually heated further in the shock pipes and finally enters the reaction zone, where at temperatures above about 400 0 C, the thermal cracking reaction begins.
• the invention is directed to a process which comprises vaporizing the feed EDC outside the cracking furnace by means of a separate apparatus.
• the sensible heat content of the reaction mixture leaving the cracking furnace is utilized in order to evaporate the EDC used before entering the cracking furnace, ie. H. the EDC evaporator is heated with the hot reactor outlet stream, hereinafter "cracked gas", which is thereby cooled, but the partial or complete condensation of the cracked gas is avoided.
• the hot reactor outlet stream hereinafter "cracked gas”
• a device has been found, as they are e.g. in EP 276,775 A2.
• Evaporator itself to the outlet nozzle of the EDC evaporator is referred to as "post-reaction zone" in the context of the invention.
• the heat of the hot zone leaving the radiation zone, hot flue gas is arranged in the adjoining the radiation zone and spatially above this
• Convection zone used by convective heat transfer for example, the following operations can be performed:
• the apparatus combination of radiation and convection zone with the associated flue gas chimney is called by the expert cracking furnace.
• the reaction mixture leaving the cracking furnace contains, in addition to the desired product VCM, also HCl (hydrogen chloride) and unreacted EDC. These are separated in subsequent process steps and returned to the process or further utilized. Furthermore, the reaction mixture contains by-products, which are also separated, worked up and further recycled or recycled back into the process. These relationships are known in the art.
• the by-products coke and tarry substances that arise over several reaction steps from low molecular weight by-products such as acetylene and benzene and settle in the coils of the cracking furnace (and in downstream equipment such as the EDC evaporator), where they a deterioration in the heat transfer, and, over the narrowing of the free cross-section, lead to an increase in the pressure loss.
• the sensible heat of the cracked gas can be used to vaporize the feed EDC.
• the cracking gas is washed in a so-called quench column by direct contact with a cool, liquid recycle or circulating stream and further cooled.
• This has, above all, the purpose of washing out coke particles contained in the cracking gas or of condensing vapor-like tarry substances and likewise of washing them out, since both components would interfere in the subsequent work-up steps.
• the cleavage gas is fed to a work-up by distillation in which the components hydrogen chloride (HCl), VCM and EDC are separated from one another.
• this work-up stage generally comprises at least one column which is operated under pressure and is recovered in pure HCl as the top product (hereinafter HCI column).
• the pressure loss over the shock pipes and the actual reactor tubes must not be too high, so that at the top of the HCI column sufficient pressure prevails in order to be able to condense the hydrogen chloride with an economically acceptable energy.
• the lower limit for this column head pressure is about 9 - 1 1 bar abs.
• the volume-time yield relative to VCM in kg VCM / (m 3 h), based on the reactor volume, ie the total volume of the reaction tubes, depends essentially on the heat flux density (dimension W / m 2 ), ie the amount of heat per unit area can be transferred through the pipe wall to the flowing reaction mixture, as well as the ratio of the surface to the volume of the reaction tube (dimension m 2 / m 3 ). Since the ratio surface / volume of the tubes decreases with increasing tube diameter, the recoverable space-time yields become increasingly smaller with increasing diameter of the reactor tubes. One way of at least partially compensating for this effect would be to increase the heat flux density.
• the thermal EDC cleavage is a radical chain reaction whose first step is the cleavage of a chlorine radical from an EDC molecule:
• the high activation energy of this first step compared to the downstream chain propagation steps is the reason why the cleavage reaction only noticeably starts above a temperature of about 420 ° C.
• heterogeneous catalyst allows the cleavage of a chlorine radical from the EDC molecule, for example by dissociative adsorption of the EDC molecule on the catalyst surface.
• very high EDC conversions can be achieved.
• Due to high local partial pressures of VCM at and near the catalyst surface decomposition of the VCM and thus coke formation on the catalyst surface occurs which leads to rapid deactivation of the catalyst.
• Due to the frequent regeneration required thereby, heterogeneous catalysts have hitherto not found entry into the large-scale production of VCM. Physical measures, such as exposure to short-wave light, provide the energy to split off the chlorine radical from an external source.
• the absorption of a short-wave light quantum by the EDC molecule provides the energy for the cleavage of the chlorine radical:
• Chemical initiators either a chlorine atom is cleaved from the EDC molecule by reaction of the EDC with the initiator, or the chlorine radicals are provided by decomposition of the initiator.
• Chemical initiators are, for example, elemental chlorine, bromine, iodine, elemental oxygen, chlorine compounds such as carbon tetrachloride (CCI 4 ), or chlorine-oxygen compounds such as hexachloroacetone.
• DE 102 19 723 A1 relates to a process for the addition of cleavage promoters in the preparation of unsaturated halogen-containing hydrocarbons. This document does not disclose details of the thermal design of the reactor.
• the problem is therefore to exploit the properties of cleavage promoters so that the space-time yield in the reaction zone of the cracking furnace is substantially increased, the required Abthesesintervalle are not shorter than in an installation of the same production capacity without the use of promoters and the heat content of the cracking gas is used to vaporize the feed used.
• Object of the present invention is to provide a reactor with respect to conventional systems significantly increased capacity. This can realize the advantages described above.
• Another object of the present invention is to provide a process for the thermal cleavage of halogenated aliphatic hydrocarbons, in which over conventional methods significantly increased space-time yields can be achieved and is characterized by a low coking tendency.
• the invention relates to a process for the thermal cleavage of halogenated aliphatic hydrocarbons to ethylenically unsaturated halogenated hydrocarbons in a reactor which comprises reaction tubes with upstream shock pipes through a convection zone and through a downstream arranged in the flow direction of the reaction gas reaction tubes, wherein burners are provided in the radiation zone, in order to supply thermal energy to the shock and reaction tubes, and comprising a heating device for the halogenated aliphatic hydrocarbon ("feed") arranged outside the reactor, which is heated with the energy content of the reaction gases leaving the radiation zone, characterized in that a) the Reaction tubes a chemical promoter for the thermal cleavage is supplied and / or within the reactor at one or more locations a locally limited energy supply to promote the thermal cleavage in the reaction tubes, b) the amount of the chemical promoter and / or the intensity of the localized energy supply to form radicals in the reaction tubes is chosen so that with the energy content of emerging from the radiation zone Reactive gases
• Surface of the shock pipes and the surface of the reaction tubes is dimensioned so that the average heat flux through the heat exchange surface of the radiation zone at least 35 kW / m 2 , preferably at least 40 kW / m 2 , and d) the conversion of the cleavage reaction, based on the used halogenated aliphatic hydrocarbon, between 50 and 65%.
• the invention further relates to a device for the thermal cleavage of halogenated aliphatic hydrocarbons to ethylenically unsaturated halogenated hydrocarbons
• a reactor which comprises a convection zone and by a downstream arranged in the flow direction of the reaction gas reaction tubes with upstream shock pipes, wherein burners are provided in the radiation zone for supplying thermal energy to the shock and reaction tubes and comprising a halogenated aliphatic hydrocarbon ("feed”) heating device located outside the reactor and heated with the energy content of the reaction gases leaving the radiation zone, comprising:
• Hydrocarbon can be evaporated without condensation occurs exiting the reaction zone reaction gases
• the production amount achievable with cleavage reactors of a given size can be increased considerably if the heat exchanger surfaces are dimensioned such that heat flow densities above 35 kW / m 2 are established, and initiation measures are used to control the reaction temperature and the reaction temperature Lower the internal wall temperature of the reaction tube.
• the educt feed stream and the heating power of the reaction furnace are increased in such a way that the conversion of the reaction does not increase significantly in comparison to processes without using initiating measures.
• the process parameters In order to continue to be able to operate the process economically despite the lowering of the reaction temperature, the process parameters must be set so that the evaporation of the amount of feed used is at least 50% by means of the sensible heat content of the reaction mixture leaving the reaction zone.
• the heat exchange takes place in this measure preferably at the outlet of the flue gas from the convection zone.
• This measure is used in particular for fuels with a low proportion of acid-forming components. However, it can also be used for fuels with a medium to high proportion of acid-forming components.
• the device according to the invention comprises, in this process variant D), at least one heat exchanger which is suitable for obtaining waste heat from the condensation of the flue gas for the preheating of the combustion air or other media, e.g. of liquid educt, is used.
• the consumption of fuel of a cracking furnace while maintaining the efficiency of the splitting process can also be significantly reduced by the measure of recovering the latent heat contained in the flue gas and the preheating of the combustion air.
• the supply of chemical promoter for the thermal cleavage can take place anywhere.
• the promoter may be added to the feed, preferably to the gaseous feed.
• the promoter is supplied to the shock or in particular the reaction tubes in the radiation zone.
• the localized power supply to promote thermal cracking occurs within the reactor at one or more locations in the reaction tubes.
• the method according to the invention is described by way of example on the system EDC / VC. It is also suitable for the production of other halogenated unsaturated carbon Hydrogens from halogen-containing saturated hydrocarbons. All these reactions have in common that the cleavage is a radical chain reaction, in addition to the desired product unwanted by-products are formed, which lead to a coking of plants in continuous operation.
• the preparation of vinyl chloride from 1, 2-dichloroethane.
• locally limited energy input for promoting the thermal cleavage into the reaction tubes means those physical measures which are capable of initiating the cleavage reaction. It may be z. B. to the coupling of high-energy electromagnetic radiation, the local supply of thermal or non-thermal plasmas, such as hot inert gases.
• average heat flux density through the heat exchange surface of the radiation zone is to be understood as meaning the total amount of heat transferred through the heat exchange surface of the steeling zone divided by the heat exchange surface of the radiation zone. This is according to the invention at least 35 kW / m 2 .
• Means for supplying chemical promoters for thermal cleavage are known in the art. These are usually feed lines which allow the introduction of predetermined amounts of chemical promoters into the feed gas stream, or they are feed lines which allow the introduction of predetermined amounts of chemical promoters into the reaction tubes at the level of the radiation zone. These feed lines may have nozzles at the reactor end. Preferably, one or more of these leads open in
• Means for supplying locally limited energy to promote thermal cracking in the reaction tubes at one or more locations of the radiation zone are also known to those skilled in the art.
• it may also be supply lines, which optionally have nozzles at the reactor end, is passed over the thermal or non-thermal plasma in the height of the radiation zone in the reaction tubes; or it may be windows, is coupled via the electromagnetic radiation or particle radiation in the height of the radiation zone in the reaction tubes.
• one or more of these feed lines open in the direction of flow of the reaction gas in the first third of the radiation zone into the pipelines; or in the first third, the windows for coupling the radiation are attached.
• Means for selecting the amount of the chemical promoter and / or the intensity of the localized energy supply to form radicals in the reaction tubes are also known in the art. These are generally control loops in which a leader is used to control the quantity or intensity. As guide variables, all process parameters can be used, with the help of which the energy content of the reaction gases emerging from the radiation zone can be concluded. Examples include the temperature of the exiting reaction gases, the content of cleavage products in the reaction gases or the wall temperature of the reaction tubes at selected locations.
• the dimensioning of the heat exchange surfaces in the radiation zone can be determined by a person skilled in the art on the basis of routine experiments.
• Electromagnetic radiation of a suitable wavelength or particle radiation is irradiated at one or more points of the shock tubes or the tubes in the reaction zone, or a chemical promoter is added or a combination of these measures takes place.
• a chemical promoter the addition may also take place in the feed line of the gaseous feed, for example to the EDC from the EDC evaporator, for entry into the cracking furnace.
• the localized energy supply for the formation of radicals by electromagnetic radiation or by particle radiation is effected; This is particularly preferably ultraviolet laser light.
• the chemical promoter may be diluted with a gas that is inert with respect to the cleavage reaction, with the use of hydrogen chloride being preferred.
• the amount of inert gas used as diluent should not exceed 5 mol% of the feed stream.
• the intensity of the electromagnetic radiation or of the particle radiation or the amount of the chemical promoter is adjusted so that the molar conversion, based on the feed used, at the gap-side outlet of the feed evaporator is between 50 and 65%, preferably between 52 and 57%.
• the heat exchange surface defined as the sum of the outer surfaces of the (un-filtered) shock pipes and the tubes in the reaction zone, is dimensioned the average heat flow density, defined as the quotient of the total heat transferred to the cracked gas in the radiation zone and the sum of the outer surface of the unaffected shock pipes and the tubes in the reaction zone, is at least 35 kW / m 2 .
• a dimensioning of the heat exchange surface is such that the average heat flow density, defined as the quotient of the total, transferred in the radiation zone to the fission gas heat and the sum of the outer surface of the unaffected shock tubes and the tubes in the reaction zone between 40 kW / m 2 and 80 kW / m 2 , more preferably between 45 kW / m 2 and 65 kW / m 2 .
• the inventive method is particularly preferably used for the thermal cleavage of 1, 2-dichloroethane to vinyl chloride.
• high space-time yield can be achieved.
• These are preferably, based on the volume of the reaction tube, defined as the sum of the volumes of the shock tubes and the reaction tubes, from entry into the radiation zone of the reactor to the exit from the radiation zone of the reactor, at least 2000 kg, preferably 3000 to 6000 kg, of ethylenic unsaturated halogenated hydrocarbons, preferably vinyl chloride, per hour and cubic meter.
• the process according to the invention also includes, as a further process step, the evaporation of the liquid feed, for example the liquid EDC, before it enters the radiation zone of the cracking furnace.
• a preferred embodiment of the invention is directed to a method in which the sensible heat of the cracking gas is utilized to produce liquid, preheated feed, For example, EDC to evaporate before entering the radiation zone, wherein preferably a heat exchanger is used, as has already been described in EP 276,775 A2. It is particularly important to ensure that on the one hand the fission gas is still hot enough when leaving the cracking furnace to evaporate with its sensible heat content, the total amount of the feed and that on the other hand, the temperature of the fission gas does not fall below a minimum value when entering this heat exchanger, to prevent the condensation of tarry substances in the heat exchanger tubes.
• the temperature of the cracking gas at the outlet from the cracking furnace is so low that the heat content of the cracking gas is insufficient to completely vaporize the feed.
• the missing portion of vaporous feed is produced by flash evaporation of liquid feed into a container, preferably in the Ausdampfgefäß a heat exchanger, as described in EP 276,775 A2.
• the preheating of the liquid feed takes place advantageously in the convection zone of the cracking furnace.
• care must be taken that the temperature of the fission gas does not fall below a minimum value when entering this heat exchanger in order to prevent the condensation of tarry substances in the heat exchanger tubes.
• the heat content of the fission gas is used to evaporate by means of indirect heat exchange at least 50% of the feed used, without the fission gas thereby partially or completely condensed.
• an apparatus is preferably used, as described for example in EP 264.065 A1.
• liquid halogenated aliphatic hydrocarbon with the hot, the ethylenically unsaturated halogenated hydrocarbon-containing product gas leaving the reactor indirectly heated, evaporated and introduced the resulting gaseous educt gas into the reactor, the liquid halogenated aliphatic hydrocarbon in a first container with the Product gas is heated to boiling and transferred from there to a second container in which it is partially evaporated without further heating under lower pressure than in the first container, the vaporized educt gas fed into the reactor and the unvaporized halogenated aliphatic hydrocarbon in the first container is returned.
• the halogenated aliphatic hydrocarbon is heated prior to feeding into the second vessel in the convection zone of the reactor with the flue gas which produces the burner heating the reactor.
• the residual amount of feed is preferably evaporated by flash evaporation in a container, wherein the feed is previously preheated in the liquid state in the convection zone of the cracking furnace.
• a container for Ent- voltage evaporation while the Ausdampfgefäß a heat exchanger is preferably used, as it is for. As described in EP 264.065 A1.
• the temperature of the reaction gas entering into the heating device arranged outside the reactor is measured and serves as a reference variable for the regulation of the addition amount of the chemical promoter and / or for the intensity of the locally limited energy supply.
• other measured variables can be used as a reference variable, for example, the content of products of the cleavage reaction.
• the molar conversion of the cleavage reaction downstream after the exit of the cleavage gas from the EDC evaporator or determined at the top of the quench column for example with an online analyzer, preferably by means of an online gas chromatograph.
• the flue gas is sucked off after leaving the convection zone by a flue gas blower and transferred into one or more heat exchangers, where it is condensed.
• the waste heat is used to heat the burner air.
• the resulting condensate is optionally worked up and discharged from the process.
• the remaining gaseous constituents of the flue gas are optionally purified and discharged into the atmosphere.
• the amount of fuel can be distributed both in equal parts as well as unequal parts on the burner rows of the furnace.
• Reactor tubes with a clear diameter of at least 200 mm, preferably from 250 to 350 mm, can be used.
• the clear diameter of the reactor tubes is not limited to these dimensions.
• the process according to the invention makes it possible to use high average heat flow densities and avoids the usually occurring disadvantages of high space-time yields in the thermic feed cleavage.
• the advantage of the method lies in particular in the fact that when setting moderate sales, which correspond to those of "conventional" methods under Use of promoters comparatively very high heat flux densities can be set and thus high heat fluxes can be transferred to the cracking gas, without the formation rates of by-products or coke are increased.
• the reason for this is that the addition of promoters and / or the use of physical measures to initiate the cleavage reaction significantly reduce the overall temperature level in the reaction chamber and the inner wall temperature of the reactor tube, whereby the reaction mixture is exposed to gentle conditions despite high heat transfer rates.
• reactors designed in accordance with the invention can be exposed to comparatively higher feed quantities without the minimum pressure required for economic separation of the reaction mixture on entry into the HCl mixture. Falls below the column.
• reactor tube diameter can be realized, which are not accessible by conventional methods, otherwise due to their low surface area / volume ratio too high internal wall temperatures would occur.
• the economy of the process is also influenced by the sum of the pressure losses of the cracking furnace (consisting of convection and radiation zone), the heat exchanger for the evaporation of the feed, and any quenching system ("quench column") which should be as small as possible in the distillative separation of cleavage products, they must be condensed at the top of a column, a chiller being used to cool the condenser, the greater the sum of the pressure losses over the entire "thermal cleavage" system, the lower the pressure at the top of the column and the separated cleavage product, for example HCl, must be condensed at a correspondingly lower temperature This leads to an increased specific energy consumption of the refrigeration machine, which in turn adversely affects the economy of the entire process.
• the invention will be explained below with reference to examples. A limitation is not intended thereby.
• 64000 kg / h of vapor EDC were in a cracking furnace at a pressure of 21 bar abs. and an inlet temperature of 360 0 C passed through a coil of 232 m in length and a clear diameter of 153.4 mm.
• a mixture of 64 kg / h of chlorine (corresponding to 1000 ppm by weight) and 250 kg / h of hydrogen chloride were added to the vaporous EDC.
• the reactor volume was 4.3 m 3 .
• the underfeuerte power was 20000 kW.
• the temperature of the cracked gas on exit from the furnace was 440 ° C; the turnover was 52.8%.
• the temperature of the flue gas at the exit from the radiation zone was 1074 ° C.
• the absorbed heat output was 8220 kW, the average heat flux density was 67 kW / m 2 .
• the reactor power was 4960 kg VCM / m 3 h.
• Example 3 36160 kg / h of vapor EDC were passed in a cracking furnace at a pressure of 21 bar abs, and an inlet temperature of 360 0 C through a coil of 130 m in length and a clear diameter of 153.4 mm.
• a mixture of 36.1 kg / h of chlorine (corresponding to 1000 ppm by weight) and 250 kg / h of hydrogen chloride were added to the vaporous EDC.
• the reactor volume was 2.4 m 3 .
• the fired power was 10,000 kW.
• the temperature of the cracked gas on exit from the oven was 433 0 C; the turnover was 52.7%.
• the temperature of the flue gas at the exit from the radiation zone was 997 ° C.
• the absorbed heat output was 4550 kW, the mean heat flux density was 72 kW / m 2 .
• the reactor power was 5010 kg VCM / m 3 h.
• 36160 kg / h of vapor EDC were in a cracking furnace at a pressure of 21 bar abs. and an inlet temperature of 360 0 C passed through a coil of 403 m in length and a clear diameter of 153.4 mm.
• the reactor volume was 7.5 m 3 .
• the fired power was 10,000 kW.
• the temperature of the cracked gas on exit from the furnace was 490 0 C; the turnover was 52.8%.
• the temperature of the flue gas on exit from the radiation zone was 866 0 C.
• the absorbed thermal output of 5290 kW, the average heat flux was 25 kW / m 2.
• the reactor power was 1606 kg VCM / m 3 h.

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  • 2009-09-03 EP EP09778304A patent/EP2344432A1/de not_active Withdrawn
  • 2009-09-03 KR KR1020117009455A patent/KR20110076967A/ko not_active Application Discontinuation
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  • 2009-09-08 TW TW098130225A patent/TW201022185A/zh unknown
• 2011
  • 2011-03-02 ZA ZA2011/01613A patent/ZA201101613B/en unknown

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