WO2009149809A1 - Procédé de production de formaldéhyde - Google Patents

Procédé de production de formaldéhyde Download PDF

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Publication number
WO2009149809A1
WO2009149809A1 PCT/EP2009/003498 EP2009003498W WO2009149809A1 WO 2009149809 A1 WO2009149809 A1 WO 2009149809A1 EP 2009003498 W EP2009003498 W EP 2009003498W WO 2009149809 A1 WO2009149809 A1 WO 2009149809A1
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Prior art keywords
reaction
zones
zone
reaction zones
reaction zone
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PCT/EP2009/003498
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German (de)
English (en)
Inventor
Evin Hizaler Hoffmann
Leslaw Mleczko
Ralph Schellen
Stephan Schubert
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Bayer Technology Services Gmbh
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Publication of WO2009149809A1 publication Critical patent/WO2009149809A1/fr

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    • 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
    • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
    • B01J8/02—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds
    • B01J8/04—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds the fluid passing successively through two or more beds
    • B01J8/0403—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds the fluid passing successively through two or more beds the fluid flow within the beds being predominantly horizontal
    • B01J8/0423—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds the fluid passing successively through two or more beds the fluid flow within the beds being predominantly horizontal through two or more otherwise shaped beds
    • B01J8/0438—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds the fluid passing successively through two or more beds the fluid flow within the beds being predominantly horizontal through two or more otherwise shaped beds the beds being placed next to each other
    • 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
    • B01J19/248—Reactors comprising multiple separated flow channels
    • B01J19/2485—Monolithic reactors
    • 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
    • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
    • B01J8/02—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds
    • B01J8/04—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds the fluid passing successively through two or more beds
    • B01J8/0403—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds the fluid passing successively through two or more beds the fluid flow within the beds being predominantly horizontal
    • B01J8/0423—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds the fluid passing successively through two or more beds the fluid flow within the beds being predominantly horizontal through two or more otherwise shaped beds
    • B01J8/0426—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds the fluid passing successively through two or more beds the fluid flow within the beds being predominantly horizontal through two or more otherwise shaped beds the beds being superimposed one above the other
    • 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
    • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
    • B01J8/02—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds
    • B01J8/04—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds the fluid passing successively through two or more beds
    • B01J8/0446—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds the fluid passing successively through two or more beds the flow within the beds being predominantly vertical
    • B01J8/0449—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds the fluid passing successively through two or more beds the flow within the beds being predominantly vertical in two or more cylindrical beds
    • B01J8/0453—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds the fluid passing successively through two or more beds the flow within the beds being predominantly vertical in two or more cylindrical beds the beds being superimposed one above the other
    • 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
    • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
    • B01J8/02—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds
    • B01J8/04—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds the fluid passing successively through two or more beds
    • B01J8/0496—Heating or cooling the reactor
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C45/00—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds
    • C07C45/27—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation
    • C07C45/32—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation with molecular oxygen
    • C07C45/37—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation with molecular oxygen of >C—O—functional groups to >C=O groups
    • C07C45/38—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation with molecular oxygen of >C—O—functional groups to >C=O groups being a primary hydroxyl group
    • 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
    • B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
    • B01J2208/00008—Controlling the process
    • B01J2208/00017—Controlling the temperature
    • B01J2208/00106—Controlling the temperature by indirect heat exchange
    • B01J2208/00168—Controlling the temperature by indirect heat exchange with heat exchange elements outside the bed of solid particles
    • B01J2208/00194—Tubes
    • 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
    • B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
    • B01J2208/00008—Controlling the process
    • B01J2208/00017—Controlling the temperature
    • B01J2208/00477—Controlling the temperature by thermal insulation means
    • B01J2208/00495—Controlling the temperature by thermal insulation means using insulating materials or refractories
    • 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
    • B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
    • B01J2208/00008—Controlling the process
    • B01J2208/00017—Controlling the temperature
    • B01J2208/0053—Controlling multiple zones along the direction of flow, e.g. pre-heating and after-cooling
    • 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
    • B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
    • B01J2208/00008—Controlling the process
    • B01J2208/00548—Flow
    • B01J2208/00557—Flow controlling the residence time inside the reactor vessel
    • 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
    • B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
    • B01J2208/00008—Controlling the process
    • B01J2208/00654—Controlling the process by measures relating to the particulate material
    • B01J2208/00707—Fouling
    • 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
    • B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
    • B01J2208/00796—Details of the reactor or of the particulate material
    • B01J2208/00805—Details of the particulate material
    • 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
    • B01J2219/00074—Controlling the temperature by indirect heating or cooling employing heat exchange fluids
    • B01J2219/00076—Controlling the temperature by indirect heating or cooling employing heat exchange fluids with heat exchange elements inside the reactor
    • B01J2219/00081—Tubes
    • 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
    • B01J2219/0015—Controlling the temperature by thermal insulation means
    • B01J2219/00155—Controlling the temperature by thermal insulation means using insulating materials or refractories
    • 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
    • B01J2219/00159—Controlling the temperature controlling multiple zones along the direction of flow, e.g. pre-heating and after-cooling
    • 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
    • B01J2219/00164—Controlling or regulating processes controlling the flow
    • B01J2219/00166—Controlling or regulating processes controlling the flow controlling the residence time inside the reactor vessel

Definitions

  • the present invention relates to a process for the preparation of formaldehyde by catalytic gas phase oxidation of methanol with oxygen, wherein the reaction is carried out in 10 to 60 successive reaction zones under adiabatic conditions, and a reactor system for carrying out the method.
  • Formaldehyde is generally prepared under the catalytic influence of metal oxides from gaseous methanol and oxygen in an exothermic, catalytic reaction according to formula (T):
  • the formaldehyde produced by the reaction of formula (I) forms an essential starting material for many other syntheses in the chemical industry.
  • formaldehyde is used in the production of dyes, pharmaceuticals and in textile finishing.
  • EP 1 551 544 (B1) discloses an apparatus and a method by means of which the reaction according to formula (I) can be carried out under pseudo-isothermal conditions.
  • the method and apparatus are characterized by having multiple reaction zones within the apparatus, the reaction zones comprising heat exchange means and catalyst. Furthermore, to control selectivity and conversion of the process, each reaction zone is charged with a process gas of different composition and operated at a different temperature, which is considered to be pseudo-isothermal over the particular reaction zone.
  • the process gases are divided into different proportions and also partially within the Reactor in a circle. Only parts of the process gas are withdrawn from the device.
  • the device and the method carried out herein are disadvantageous, since the expenditure on equipment for the division of the process gases into partial streams whose controlled task in the individual reaction zones and the pseudo-isothermal procedure in these is very high. Furthermore, the three reaction zones disclosed by the circulation of the process gases in the reactor are not considered to be separate from each other, so that precise coordination of temperature and process gas composition in the individual reaction zones is only possible by complex control mechanisms, since a stable operating point initially set and it must be checked continuously.
  • US Pat. No. 2,504,402 discloses an apparatus and a process in which the reaction according to formula (I) is carried out in several successive adiabatic reaction zones, a heat exchange zone in each case between the individual adiabatic reaction zones.
  • methanol is fed in each case before each reaction zone and / or heat exchange zone, the reaction zones each being operated in such a way that no methanol is present in the process gas downstream of the reaction zone.
  • the procedure is disadvantageous because each reaction zone requires a quantitative conversion.
  • EP 1 251 951 (B1) discloses a device and the possibility of carrying out chemical reactions in the device, wherein the device is characterized by a cascade of reaction zones in contact with one another and heat exchanger devices which are arranged in a composite with one another. The process to be carried out herein is thus characterized by the contact of the various reaction zones with a respective heat exchanger device in the form a cascade. There is no disclosure as to the usability of the apparatus and method for the synthesis of formaldehyde from gaseous oxygen and methanol. Thus, it remains unclear how, starting from the disclosure of EP 1 251 951 (B1), such a reaction should be carried out by means of the device and the method carried out therein.
  • EP 1 251 951 (B1) is carried out in a device the same as or similar to the disclosure regarding the device.
  • the disclosure with regard to the oscillating temperature profile can therefore only be understood as meaning that the temperature peaks ascertained here would be stronger if this contact did not exist.
  • Another indication of this is the exponential increase in the disclosed temperature profiles between the individual temperature peaks. These indicate that there is some heat sink of appreciable but limited capacity in each reaction zone which can reduce the temperature rise in it.
  • EP 1 251 951 discloses multi-stage processes in cascades of reaction zones from which heat in an undefined amount is removed by heat conduction. Accordingly, the disclosed method is disadvantageous in that accurate temperature control of the process gases of the reaction is not possible.
  • EP 0 820 345 discloses a process for the production of formaldehyde by catalytic gas phase oxidation of methanol with oxygen and an apparatus in which it can be carried out, comprising a plurality of adiabatic reaction zones.
  • the revealed plurality is not limited. However, it is disclosed in the figures and exemplary embodiments that a maximum number of five adiabatic reaction zones can be present. It is further disclosed that heat exchange zones may be located between the adiabatic reaction zones. - A -
  • these heat exchange zones are connected to each other in such a way that they communicate with each other via a single heat exchange medium.
  • EP 0 820 345 (B1) is disadvantageous since, with the small number of adiabatic reaction zones and the central heat exchange zones, precise control and / or control of the temperature profile over the reaction zones is not possible. The reason for this is that a complex interconnection of the reaction zones with the heat exchange zones is forced, which in turn leads to a mutual influence of the reaction zones.
  • the mutual influence is particularly disadvantageous in particular in the exothermic reaction according to formula (I), since with an adiabatic temperature increase in one of the maximum five reaction zones, which exceeds the previously calculated level, the coolant of the subsequent heat exchange zone is heated more strongly. This in turn leads to a lower cooling effect in the subsequent heat exchange zone, so that a disproportionate heating of the next but one reaction zone must be feared.
  • Methanol in the context of the present invention refers to a process gas which is introduced into the process according to the invention and which essentially comprises methanol. Essentially, in the context of the present invention, a proportion of more than 90% by weight. As a result, methanol present in the liquid phase is first vaporized before being fed to the process.
  • Oxygen in the context of the present invention, refers to a process gas which is introduced into the process according to the invention and which essentially comprises oxygen.
  • oxygen is ambient air and therefore comprises a proportion of about 20% by volume of oxygen.
  • methanol and oxygen can also include secondary components.
  • minor components that may be included in the process gases include nitrogen, dimethyl ether, carbon dioxide, carbon monoxide, and water.
  • process gases are understood as gas mixtures which comprise oxygen and / or methanol and / or formaldehyde and / or secondary components.
  • process gases include oxygen and / or methanol and / or formaldehyde.
  • adiabat means that no heat supply or removal measures are taken.
  • An advantage of the adiabatic driving method according to the invention of the 10 to 60 reaction zones connected in series with respect to a non-adiabatic driving mode is that no heat removal means need be provided in the reaction zones, which results in a considerable simplification of the construction. This results in particular simplifications in the manufacture of the reactor and in the scalability of the process and an increase in reaction conversions.
  • the heat generated in the course of the exothermic reaction progress can be utilized in the single reaction zone to increase the conversion in a controlled manner.
  • Another advantage of the method according to the invention is the possibility of very accurate temperature control, due to the close staggering of adiabatic reaction zones. It can thus be set in each reaction zone advantageous in the reaction progress temperature.
  • the catalysts used in the process according to the invention are usually catalysts which consist of a material which, in addition to its catalytic activity for the reaction of the formula (I), is characterized by sufficient chemical resistance to oxygen under the conditions of the process and by a high specific surface area.
  • Catalyst materials characterized by such chemical resistance to oxygen under the conditions of the process include, for example, catalysts comprising iron and molybdenum.
  • Specific surface area in the context of the present invention refers to the area of the catalyst material that can be reached by the process gases based on the mass of catalyst material used.
  • a high specific surface area is a specific surface area of at least 1 m 2 / g, preferably of at least 2 m 2 / g.
  • the catalysts of the invention are each in the reaction zones and can be used in all known forms, e.g. Fixed bed, fluidized bed, fluidized bed present.
  • the fixed bed arrangement comprises a catalyst bed in the strict sense, ie loose, supported or unsupported catalyst in any form and in the form of suitable packings.
  • catalyst bed as used herein also includes contiguous areas of suitable packages on a carrier. material or structured catalyst support. These would be, for example, to be coated ceramic honeycomb carrier with comparatively high geometric surfaces or corrugated layers of metal wire mesh on which, for example, catalyst granules is immobilized.
  • a special form of packing in the context of the present invention, the presence of the catalyst in monolithic form is considered.
  • the catalyst is preferably present in beds of particles with average particle sizes of 1 to 10 mm, preferably 1, 5 to 8 mm, particularly preferably 2 to 5 mm.
  • a monolithic catalyst comprising iron and molybdenum.
  • the monolithic catalyst is provided with channels through which the process gases flow.
  • the channels have a diameter of 0.1 to 3 mm, preferably a diameter of 0.2 to 2 mm, more preferably from 0.5 to 1, 5 mm.
  • a monolithic catalyst with channels of the specified diameter is particularly advantageous, since this explosion protection can be ensured. This is done by absorbing the enthalpy through the wall of the monolith and thus suppressing further propagation of flames.
  • the catalyst is preferably present in loose beds of particles, as have also previously been described for the fixed bed arrangement.
  • Beds of such particles are advantageous because the size of the particles have a high specific surface area of the catalyst material compared to the process gases oxygen and methanol and thus a high conversion rate can be achieved. Thus, the mass transport limitation of the reaction by diffusion can be kept low. At the same time, however, the particles are not yet so small that disproportionately high pressure losses occur when the fixed bed flows through.
  • the ranges of the particle sizes given in the preferred embodiment of the process, comprising a reaction in a fixed bed are thus an optimum between the achievable turnover from the reaction according to formula (I) and the generated pressure loss when carrying out the process. Pressure loss is coupled in a direct manner with the necessary energy in the form of compressor performance, so that a disproportionate increase in the same would result in an inefficient operation of the method.
  • the conversion takes place in 12 to 50, more preferably 15 to 30 reaction zones connected in series.
  • a preferred further embodiment of the method is characterized in that the process gas emerging from at least one reaction zone is subsequently passed through at least one heat exchange zone downstream of said reaction zone.
  • each reaction zone is at least one, preferably exactly one heat exchange zone, through which the process gas leaving the reaction zone is passed.
  • the reaction zones can either be arranged in a reactor or arranged divided into several reactors.
  • the arrangement of the reaction zones in a reactor leads to a reduction in the number of apparatuses used.
  • the individual reaction zones and heat exchange zones can also be arranged together in a reactor or in any combination of reaction zones with heat exchange zones in several reactors.
  • reaction zones and heat exchange zones are present in a reactor, then in an alternative embodiment of the invention there is a heat insulation zone between them, in order to be able to obtain the adiabatic operation of the reaction zone.
  • each of the series-connected reaction zones can be replaced or supplemented independently of one another by one or more reaction zones connected in parallel.
  • the use of reaction zones connected in parallel allows in particular their replacement or supplementation during ongoing continuous operation of the process.
  • Parallel and successive reaction zones may in particular also be combined with one another.
  • the process according to the invention particularly preferably has exclusively reaction zones connected in series.
  • the reactors preferably used in the process according to the invention can consist of simple containers with one or more reaction zones, as e.g. in Ullmann's Encyclopedia of Industrial Chemistry (Fifth, Completely Revised Edition, VoI B4, page 95-104, page 210-216), wherein in each case between the individual reaction zones and / or heat exchange zones heat insulation zones can be additionally provided.
  • the catalysts or the fixed beds thereof are mounted in a manner known per se on or between gas-permeable walls comprising the reaction zone of the reactor.
  • technical devices for uniform gas distribution can be provided in the flow direction in front of the catalyst beds. These can be perforated plates, bubble-cap trays, valve trays or other internals which cause a uniform entry of the process gas into the fixed bed by producing a small but uniform pressure loss.
  • a molar excess of between 0 and 500% oxygen based on the molar flow of methanol, before it enters the first reaction zone.
  • the inlet temperature of the process gas entering the first reaction zone is from 10 to 330 ° C., preferably from 50 to 310 ° C., particularly preferably from 100 to 290 ° C.
  • the absolute pressure at the inlet of the first reaction zone is between 1 and 4 bar, preferably between 1.1 and 3 bar, more preferably between 1.2 and 2.5 bar.
  • the residence time of the process gas in a reaction zone is between 0.1 and 50 s, preferably between 0.2 and 20 s, particularly preferably between 0.5 and 10 s.
  • the methanol and the oxygen are preferably fed only before the first reaction zone.
  • This has the advantage that the entire process gas can be used for the absorption and removal of the heat of reaction in all reaction zones.
  • the space-time yield can be increased, or the necessary catalyst mass can be reduced.
  • the temperature of the conversion can be controlled via the supply of gas between the reaction zones.
  • the process gas is cooled after at least one of the reaction zones used, more preferably after each of the catalyst beds used.
  • the process gas is passed after exiting a reaction zone through one or more of the above-mentioned heat exchange zones, which are located behind the respective reaction zones.
  • These may be used as heat exchange zones in the form of heat exchangers known to those skilled in the art, e.g. Tube bundle, plate, Ringnut-, spiral, finned tube, micro-heat exchanger be executed.
  • the heat exchangers are preferably microstructured heat exchangers.
  • steam is generated during cooling of the process gas in the heat exchange zones by the heat exchanger.
  • the heat exchangers which include the heat exchange zones, to carry out evaporation on the side of the cooling medium, preferably partial evaporation.
  • Partial evaporation in the context of the present invention, refers to evaporation in which a gas / liquid mixture of a substance is used as the cooling medium is used and in which even after heat transfer in the heat exchanger is still a gas / liquid mixture of a substance.
  • the carrying out of evaporation is particularly advantageous because in this way the achievable heat transfer coefficient from / to process gases on / from the cooling / heating medium becomes particularly high and thus efficient cooling can be achieved.
  • the export of a partial evaporation is particularly advantageous because the absorption / release of heat by the cooling medium thereby no longer results in a temperature change of the cooling medium, but only the gas / liquid balance is shifted. This has the consequence that over the entire heat exchange zone, the process gas is cooled to a constant temperature. This in turn safely prevents the occurrence of temperature profiles in the flow of process gases, thereby improving control over the reaction temperatures in the reaction zones and, in particular, preventing the formation of local overheating by temperature profiles.
  • a mixing zone can also be provided upstream of the entrance of a reaction zone in order to standardize the temperature profiles in the flow of process gases which may arise during cooling by mixing transversely to the main flow direction.
  • the reaction zones connected in series are operated at an average temperature increasing or decreasing from reaction zone to reaction zone.
  • the temperature can be both increased and decreased from reaction zone to reaction zone. This can be adjusted, for example, via the control of the heat exchange zones connected between the reaction zone. Further options for setting the average temperature are described below.
  • the thickness of the flow-through reaction zones can be chosen to be the same or different and results according to laws generally known in the art from the residence time described above and enforced in each case in the process
  • Process gas quantities are usually between 0.01 and 25 t / h, preferably between 0.1 and 20 t / h, more preferably between 1 and 10 t / h.
  • the maximum outlet temperature of the process gas from the reaction zones is usually in a range from 260 ° C to 400 ° C, preferably from 280 0 C to 380 0 C, particularly preferably from 300 0 C to 350 0 C.
  • Reaction zones are preferably carried out by at least one of the following measures:
  • reaction zones addition of gas between the reaction zones, molar ratio of the starting materials / excess of oxygen used, addition of inert gases, in particular
  • the composition of the catalysts in the reaction zones according to the invention may be identical or different. In a preferred embodiment, the same catalysts are used in each reaction zone. However, it is also advantageous to use different catalysts in the individual reaction zones. Thus, especially in the first reaction zone, when the concentration of the reaction educts is still high, a less active catalyst can be used and in the further reaction zones the activity of the catalyst can be increased from reaction zone to reaction zone.
  • the control of the catalyst activity can also be carried out by dilution with inert materials or carrier material. Also advantageous is the use of a catalyst in the first and / or second reaction zone, which is particularly stable against deactivation at the temperatures of the process in these reaction zones.
  • 0.1 kg / h to 10 kg / h preferably 0.5 kg / h to 8 kg / h, particularly preferably 1 kg / h to 5 kg / h of formaldehyde can be produced by the process according to the invention per 1 kg of catalyst.
  • the inventive method is thus characterized by high space-time yields, combined with a reduction of the apparatus sizes and a simplification of the apparatus or reactors.
  • This surprisingly high space-time yield is made possible by the interaction of the inventive and preferred embodiments of the new method.
  • the interaction of staggered, adiabatic reaction zones with intermediate heat exchange zones and the defined Residence times enable precise control of the process and the resulting high space-time yields, as well as a reduction in the by-products formed, such as dimethyl ether, dimethoxymethane and carbon monoxide.
  • Another object of the invention is a reactor system for the reaction of methanol and oxygen to formaldehyde, characterized in that it feeds (Z) for a process gas comprising methanol and oxygen or for at least two process gases, of which at least one methanol and at least one oxygen and 10 to 60 reaction zones (R) connected in series in the form of fixed beds of a heterogeneous catalyst, heat insulation zones (I) in the form of insulating material and between these heat exchange zones (W) in the form of plate heat exchangers being connected to the reaction zones. and discharges for the process gases are connected and include the supply and discharge lines for a cooling medium.
  • the reactor system may also comprise 12 to 50, preferably 15 to 30 reaction zones in the form of fixed beds.
  • the insulating material of the heat insulating zones is preferably a material having a
  • FIG. 1 shows a schematic representation of an embodiment of the reactor system according to the invention, the following reference numerals being used in the figures:
  • W heat exchange zone (s) 2 shows reactor temperature (T), methanol conversion (U) and formaldehyde selectivity (Y) over a number of 23 reaction zones (S) with downstream heat exchange zones (according to Example 1).
  • T reactor temperature
  • U methanol conversion
  • Y formaldehyde selectivity
  • the process gas flows through a total of 23 fixed catalyst beds of iron and molybdenum, ie through 23 reaction zones.
  • Each after a reaction zone is a heat exchange zone in which the process gas was cooled before it enters the next reaction zone.
  • the process gases used at the beginning of the first reaction zone are methanol and air, the volume flow of the air being set so that an excess of 400% of the oxygen based on methanol is present at the beginning of the first reaction zone.
  • the absolute inlet pressure of the process gas directly in front of the first reaction zone is 1, 1 bar.
  • the length of the fixed catalyst beds, ie the reaction zones is always 0.1 m.
  • the activity of the catalyst used changes from reaction zone to reaction zone (see Table 1) (the activity of the last reaction zone was normalized to 100%). There is no replenishment of process gases before the individual catalyst stages.
  • the residence time in the entire system is 1.2 seconds.
  • the results are shown in FIG.
  • the individual reaction zones are listed on the x-axis, so that a spatial course of developments in the process is visible.
  • the temperature of the process gas is indicated on the left y-axis.
  • the temperature profile across the individual reaction zones is shown as a thick, solid line.
  • the right-hand y-axis shows the total methanol conversion and the selectivity of formaldehyde.
  • the course of the conversion over the individual reaction zones is shown as a thick dashed line.
  • the course of selectivity as a thin solid line.
  • the inlet temperature of the process gas before the first reaction zone is about 285 0 C. Due to the exothermic reaction to formaldehyde under adiabatic conditions, the temperature in the first reaction zone rises to about 300 0 C, before the process gas is cooled in the downstream heat exchange zone again. The inlet temperature before the next reaction zone is about 285 ° C. By exothermic adiabatic reaction, it rises again to about 300 0 C. The sequence of heating and cooling continues. The inlet temperatures of the process gas upstream of the individual reaction zones essentially do not change during the course of the process. This is advantageous, since in the course of the reaction a constant temperature is thus used on average, which enables optimum selectivity of formaldehyde.
  • a method according to this specific embodiment requires the specified overhead of reaction and heat exchange zones, but this has no linear economic effects due to the similarity of the components. There is obtained a conversion of methanol of 99 mol%. The selectivity is kept constant at 95.5 mol%. The space-time yield obtained, based on the mass of catalyst used, is 2.67 kg F ⁇ rm a i d e hy ci / kg C at h.
  • the process gas flows through a total of 16 reaction zones, ie over 16 fixed catalyst beds of iron and molybdenum.
  • Each after a reaction zone is a heat exchange zone in which the process gas is cooled before it enters the next reaction zone.
  • the process gases used at the outset are, like the inlet pressure before the first reaction zone, identical to those of Example 1.
  • the length of the catalyst stages, ie the reaction zones, is shown in Table 2.
  • the activity of the catalyst is in the first reaction zone 100% in all other is set by dilution with catalytically inactive material has an activity of 5.7%. This is achieved after the first reaction zone oscillating, in a temperature window between 280 0 C and 320 0 C, on which the process settles. There is no replenishment of gas before the individual catalyst stages.
  • the residence time in the entire system is 1.1 seconds.
  • the results are shown in FIG.
  • the individual reaction zones are listed on the x-axis, so that a spatial course of developments in the process is visible.
  • the temperature of the process gas is indicated on the left y-axis.
  • the temperature profile across the individual reaction zones is shown as a thick, solid line.
  • the right-hand y-axis shows the total methanol conversion and the selectivity of formaldehyde.
  • the course of the conversion over the individual reaction zones is shown as a thick dashed line.
  • the course of selectivity as a thin solid line.
  • the inlet temperature of the process gas before the first reaction zone is about 175 ° C.
  • the temperature rises to about 320 0 C before entering the second reaction zone, before the process gas is cooled in the downstream heat exchange zone.
  • the inlet temperature before the next reaction zone is again about 280 0 C.
  • exothermic adiabatic reaction it rises again to about 320 0 C.
  • the sequence of heating and cooling continues.
  • the inlet temperatures of the process gas upstream of the individual reaction zones increase with increasing number of reaction zones and settle around a mean value of about 320 ° C.
  • FIG. 10 Another feature of the operation of the reaction zones under adiabatic conditions is shown in FIG. If one observes in particular the shape of the temperature profile within the reaction zones 10 to 16 and the shape of their temperature profile, it can be seen that the slope of the temperature increase over the reaction zone decreases. This shows the essential property of the process that no significant heat sink is present in the reaction zones.

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  • Chemical Kinetics & Catalysis (AREA)
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  • Fluid Mechanics (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
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Abstract

L'invention concerne un procédé utilisé pour produire du formaldéhyde par oxydation catalytique en phase gazeuse de méthanol avec de l'oxygène, la réaction étant effectuée dans 10 à 60 zones de réaction successives, dans des conditions adiabatiques. L'invention concerne également un système de réacteur utilisé pour mettre ledit procédé en oeuvre.
PCT/EP2009/003498 2008-05-29 2009-05-16 Procédé de production de formaldéhyde WO2009149809A1 (fr)

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DE102010040923A1 (de) 2010-09-16 2012-03-22 Basf Se Verfahren zur Herstellung von Acrylsäure aus Ethanol und Formaldehyd
WO2012034929A2 (fr) 2010-09-16 2012-03-22 Basf Se Procédé de production d'acide acrylique à partir d'éthanol et d'acide acétique
CN114643022A (zh) * 2020-12-21 2022-06-21 浙江国宇塑业有限公司 一种防爆型甲醛生产装置

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US2504402A (en) * 1945-10-27 1950-04-18 Du Pont Formaldehyde synthesis
WO1996032190A1 (fr) * 1995-04-11 1996-10-17 Floriall Holdings Limited Procede et reacteur pour la synthese exothermique heterogene du formaldehyde
WO2001054806A1 (fr) * 2000-01-25 2001-08-02 Meggitt (Uk) Ltd Reacteur chimique comportant un echangeur de chaleur
WO2007134771A1 (fr) * 2006-05-23 2007-11-29 Bayer Materialscience Ag Procédé de production de chlore par oxydation en phase gazeuse

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EP1410842A1 (fr) 2002-10-17 2004-04-21 Ammonia Casale S.A. Procédé permettant de réaliser des reactions chimiques d'oxydation fortément exothermiques sous des conditions pseudo-isothermes

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US2504402A (en) * 1945-10-27 1950-04-18 Du Pont Formaldehyde synthesis
WO1996032190A1 (fr) * 1995-04-11 1996-10-17 Floriall Holdings Limited Procede et reacteur pour la synthese exothermique heterogene du formaldehyde
WO2001054806A1 (fr) * 2000-01-25 2001-08-02 Meggitt (Uk) Ltd Reacteur chimique comportant un echangeur de chaleur
WO2007134771A1 (fr) * 2006-05-23 2007-11-29 Bayer Materialscience Ag Procédé de production de chlore par oxydation en phase gazeuse

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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102010040923A1 (de) 2010-09-16 2012-03-22 Basf Se Verfahren zur Herstellung von Acrylsäure aus Ethanol und Formaldehyd
WO2012034929A2 (fr) 2010-09-16 2012-03-22 Basf Se Procédé de production d'acide acrylique à partir d'éthanol et d'acide acétique
WO2012035019A1 (fr) 2010-09-16 2012-03-22 Basf Se Procédé de production d'acide acrylique à partir d'éthanol et de formaldéhyde
US8507721B2 (en) 2010-09-16 2013-08-13 Basf Se Process for preparing acrylic acid from ethanol and formaldehyde
US8877966B2 (en) 2010-09-16 2014-11-04 Basf Se Process for preparing acrylic acid from methanol and acetic acid
CN114643022A (zh) * 2020-12-21 2022-06-21 浙江国宇塑业有限公司 一种防爆型甲醛生产装置
CN114643022B (zh) * 2020-12-21 2023-11-28 浙江国宇塑业有限公司 一种防爆型甲醛生产装置

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