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
  • B01J19/24—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
  • B01J15/00—Chemical processes in general for reacting gaseous media with non-particulate solids, e.g. sheet material; Apparatus specially adapted therefor
  • B01J15/005—Chemical processes in general for reacting gaseous media with non-particulate solids, e.g. sheet material; Apparatus specially adapted therefor in the presence of catalytically active bodies, e.g. porous plates
• • 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
  • B01J19/2415—Tubular reactors
  • B01J19/2425—Tubular reactors in parallel
• • 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
  • B01J19/28—Moving reactors, e.g. rotary drums
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10K—PURIFYING OR MODIFYING THE CHEMICAL COMPOSITION OF COMBUSTIBLE GASES CONTAINING CARBON MONOXIDE
  • C10K1/00—Purifying combustible gases containing carbon monoxide
  • C10K1/20—Purifying combustible gases containing carbon monoxide by treating with solids; Regenerating spent purifying masses
  • C10K1/30—Purifying combustible gases containing carbon monoxide by treating with solids; Regenerating spent purifying masses with moving purifying masses
• • 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

Definitions

• the present invention relates to a rotary reactor, more specifically a rotary ceramic monolith reactor, which is suitable for carrying out cyclic processes.
• sorption and regeneration For continuously carrying out cyclic processes, such as sorption/regeneration processes, catalytic processes in general, such as selective oxidation, for instance oxidation of butane to MZA, ethylene to ethylene oxide, or propylene to propylene oxide, as well as methane conversion and catalytic cracking, rotary reactors are an attractive alternative.
• sorption and regeneration, or reaction and regeneration occur simultaneously, in separate sections. By rotating the reactor the sections are alternately sub ected to sorption/reaction conditions, or to regeneration conditions, in that per section a different gas is passed through.
• two-step or multiple step reactions can be carried out as well.
• one of the objectives of the invention is to provide a reactor system that is suitable for continuously carrying out cyclic chemical processes, such as sorption/desorption, in a single reactor, at elevated temperature, and under typically corrosive conditions.
• a rotary reactor consisting of a number of tubular reaction compartments each provided with a first end and a second end, a ceramic first reactor end plate in which said first ends are received and a second end plate in which said second ends are received, which end plates are further provided with means for feeding and/or discharging gases, and wherein against the first end plate a first ceramic flange is arranged of the same material as said first end plate, which flange is provided with openings for the supply and discharge of gases, which openings correspond at least partly to openings in said first end plate, and wherein the assembly of flange and said first end plate are arranged against each other under pressure while rotating relative to each other.
• the second end plate is manufactured from ceramic material and a second flange of the same material as the second end plate is arranged against the second end plate.
• the second flange is provided with means for discharging and feeding gases from the reaction compartments, and/or for recirculating gases from one or more reaction compartments to one or more other reaction compartments .
• the tubular reaction compartments can have various shapes, it being of importance that the length is greater than the diameter. Suitable are, for instance, round tubes, but rectangular, square or, more generally defined, x-angular channels can also be suitably used. In addition, it is also possible to construct the reaction compartments combined with reactor end plates as channels in a block of the material of the reactor.
• the use of the reactor according to the present invention for carrying out physical, chemical and physicochemical cyclic processes has the surprising advantage that no problems occur with the sealing of the flanges, while yet a good rotation remains possible.
• the sealing occurs without necessitating difficult constructions. It can suffice to make the two surfaces of the ceramic plates forming the flange to fit each other and in operation to apply some force to both sides of the flange, so that the surfaces remain clamped against each other. This holds for both flanges.
• Making the two components of the seal to fit each other occurs by grinding the plates to fit each other. After cleaning, the system can be used without necessitating additional sealing or lubrication. If desired, a lubricating compound, such as boron nitride, graphite, or another suitable material, can be used a single time to fill up very small uneven spots in the plates (typically ⁇ 0.2 ⁇ m) .
• the reaction compartments will on at least one side terminate in a reactor end plate. It is possible that on only one side a flange is present, with provisions for the supply and discharge of gases, while in the second end plate fixed connections are made between two or more reactor compartments. In that case there is only one rotary sealing surface, which can be advantageous from the point of view of construction and sealing. In case flexible process control is to be enabled, it may provide advantages to make provisions on both sides of the reactor for varying the connections between the reaction compartments.
• the design of the reactor according to the invention will vary depending on the use contemplated. A few variants are elucidated in the drawing.
• reaction compartments will mostly be greater than two, while for carrying out cyclic chemical processes often not more than two reaction sections are desired, a number of reaction compartments will, in accordance with the invention, simultaneously fulfill the same function. To realize this in the proper manner, that is to say that each reaction compartment is approached by gas flow in the same manner, it is desired that the supply and discharge flanges be provided with suitable distribution channels for the gas.
• the reactor according to the invention is used for carrying out cyclic processes.
• cyclic processes include sorption/regeneration processes, selective oxidation, for instance oxidation of butane to MZA, ethylene to ethylene oxide, or propylene to propylene oxide, as well as methane conversion and catalytic cracking. All these processes have in common that there are separate sections in the process, where work is done under different conditions, or with different gases.
• Catalytic processes are generally based on a system of elementary steps that are catalyzed by the catalyst. During the process, a complex fluid phase is present, of which reactants and products are simultaneously present on the surface. For an efficient process the load factors must be set optimally. To that end, the conditions are optimally chosen, being temperature and pressures or concentrations. This kind of processes can also be carried out in several compartments, allowing the conditions in each compartment to be chosen optimally. Examples are FCC (riser reactor in which the feed is cracked) and a regenerator (where the combustion takes place) , selective oxidation of butane to maleic acid anhydride, whereby in one reactor the oxidation of butane occurs and in the second reactor the catalyst is oxidized.
• FCC regulator reactor in which the feed is cracked
• regenerator where the combustion takes place
• the reaction compartments are filled with monolith, on which an active component has been provided.
• the major advantage of such a system is that with large gas streams only a low pressure drop occurs, while further the system is virtually insensitive to dust. This can specifically be of importance when using the reactor for treating gases coming from a coal gasifier. It is also possible, however, to provide the active material in the form of a granular material, for instance powder, granulate or extrusions.
• the active component, catalyst or sorbent is preferably provided on the surface of a carrier material, such as a monolith.
• a carrier material such as a monolith.
• a newly developed sorbent based on metal compounds, more particularly on manganese compounds is used.
• a characteristic of this sorbent is that it is built up of a combination of a metal aluminate with, dispersedly distributed on the surface thereof, the corresponding metal oxide.
• Suitable metals for that purpose are inter alia manganese, copper, iron, cobalt and other metals which are known to be suitable for sorbing sulfur.
• Manganese is most preferred and the preparation and use will hereinafter be discussed with reference to manganese, although this is to be understood to mean that other metals can be comparable.
• the sorbent can be obtained by dry or wet impregnation of a ⁇ -Al 2 0 3 carrier with a manganese solution, for instance a 1.5 M solution of manganese acetate. After impregnation and removal of any excess impregnation liquid, the sample is rapidly dried, for instance in a microwave oven. Then it is further dried in a conventional oven at 363 K, followed by calcination at 673 to 973 K.
• the carrier can consist, for instance, of ⁇ -Al 2 0 3 particles, pure ⁇ -Al 2 0 3 monoliths or cordierite monoliths with a washcoat layer of, for instance, 25% by weight of ⁇ -Al 2 0 3 .
• the concentration of manganese on the sorbent can be increased by impregnating and calcining a sample a number of times.
• Manganese acetate as contrasted with, for instance, manganese citrate, is very well distributed over the surface of the ⁇ -Al 2 0 3 carrier. This is due to the good interaction of the manganese acetate with external -OH groups present on the alumina surface.
• a sample is calcined in an air atmosphere at a temperature between 673 and 973 K. Depending on the calcination temperature, this yields MnAl ? 0 and disperse Mn0 2 , Mn 2 0 3 or Mn 4 0 4 (or a mixture) on the surface of the carrier.
• MnAl 2 0 4 is formed, which is thermodynamically stabler than MnO .
• diluted oxygen is used (as regeneration with oxygen is highly exothermic) to form S0 2 .
• S0 2 in a low concentration is a product with a low market value.
• H 2 S is a much more attractive product because this can be simply converted to elemental sulfur in a Claus plant.
• the direct production of S during the regeneration is the most attractive option. This could be accomplished by regeneration with S0 2 .
• sulfate formation leads to a very rapid deactivation of the sorbent if regeneration is done with S0 2 .
• the relatively simple regeneration with steam of bulk manganese aluminate means that manganese aluminate is relatively sensitive to water in the coal gas.
• Coal gas of the Shell gasification process typically contains 0.4-2% water.
• the bulk manganese aluminate will not be able to remove the H 2 S from the process gas to a sufficient extent.
• a solution to the water sensitivity could be to use a sorbent material with a high reaction equilibrium constant, such as, for instance, MnO. This, however, presents the earlier mentioned problem that the bulk material of MnO is poorly regenerable and that regeneration costs a great deal of regeneration gas. Only disperse MnO is regenerable with a high speed at a temperature of 1123 K.
• the new sorbent material that has been developed within the framework of the present invention, and which is highly suitable for use in the reactor according to the invention, also contains, in addition to bulk manganese aluminate, MnO that is present at the surface highly dispersedly (the metal oxide has an average particle size of 100 nm at a maximum, more particularly 5 nm at a maximum) .
• MnO that is present at the surface highly dispersedly
• the amount of MnO on the surface can be adjusted to the amount of H 2 S that is allowed to pass by the bulk manganese aluminate.
• the amount that is allowed to pass is dependent on the amount of water in the feed (see reaction scheme Fig. 10) .
• manganese aluminate contains at most 32% by weight of manganese. If more manganese than this 32% is provided on the carrier, upon sulfidation and regeneration two phases are formed, viz. bulk manganese aluminate and a disperse manganese oxide phase which is located (chiefly) at the surface.
• (bulk) manganese aluminate provides for a high capacity and a relatively simple regeneration.
• Disperse manganese oxide provides for the removal of H 2 S to low concentrations.
• the amount of disperse manganese oxide can, as already indicated, vary within wide limits. In general, of the amount of manganese, about 1 to 25% will be present in the form of manganese oxide, while the rest is present as manganese aluminate.
• This sorbent material is provided on a washcoated cordierite monolith and was tested during 110 cycles (See Fig. 9) . After an initial deactivation of ⁇ 10% during the first 10 cycles, the performance of the material remains stable during these 110 cycles.
• Figs. 1 and 1A show the basic principle of the rotary reactor;
• Fig. 2 shows the parts of the rotary reactor;
• Fig. 3 represents the rotary reactor in the oven of the benchscale set-up
• Fig. 4 shows an example of the sorbent material provided on a cordierite monolith with 25% by weight of ⁇ -Al 2 0 3 washcoat layer;
• Fig. 5 shows a typical sulfidation and regeneration curve
• Figs. 6A and 6B show examples of the H 2 S concentration during sulfidation and regeneration of the rotary monolith reactor
• Fig. 7 shows the effect of increasing the number of reactor compartments to 25 in the regeneration section on the H ? S output concentration during the regeneration;
• Fig. 8 shows the sulfidation capacity as a function of the temperature;
• Fig. 9 shows the deactivation of the sorbent during 110 cycles; and Fig. 10 shows a reaction scheme.
• Fig. 1 the basic principle of the reactor construction is given.
• the reactor compartment is designated by A, while the end plates are designated by B.
• A+B together form the rotary part of the reactor.
• the flanges D are clamped against the end plates by means of a pressure system, not shown, for instance a spring system.
• a rotary reactor is shown which is based on the principle as indicated in Fig. 1.
• the reactor (see Figs. 2+3) now includes three flanges/plates on both sides of the reactor compartments (reactor end plate (a), reactor intermediate flange (b) , reactor end flange (c) ) , while in Fig. 1 only two flanges/plates are represented on either side.
• the number of reactor compartments (tubes) and the division of the sections in the reactor intermediate flanges differ from Fig. 1.
• the reactor rotor consists of sixteen tubes (reactor compartments) arranged substantially parallel to each other with an internal diameter of 1 cm, a wall thickness of 3 mm and a length of 30 cm. These reactor compartments terminate on either side in a reactor end plate of a thickness of 1.5 cm and a diameter of 15 cm. Reactor compartments with reactor end plates together form the rotary part of the reactor (the reactor rotor) . Arranged against the reactor end plates on opposite sides is a flat plate of a thickness of 1.5 cm and a diameter of 15 cm (reactor intermediate flange).
• this reactor intermediate flange includes four sections for supplying and discharging gases: two large sections (covering six reactor compartment ends) each providing for the supply or discharge of process gases (for instance, regeneration gas, coal gas, cleaned coal gas and "used” regeneration gas) and two small sections (covering two reactor compartment ends) providing for the supply and the discharge of flushing gas.
• process gases for instance, regeneration gas, coal gas, cleaned coal gas and "used” regeneration gas
• small sections covering two reactor compartment ends
• the section for feeding and removing coal gas can be greater than the section for the regeneration, for instance, eight reactor compartments in a section for the sulfidation and four for the regeneration.
• a round hole with a diameter of 8 mm which opens into a similar hole in a reactor end flange.
• a round hole is present through which passes the drive shaft.
• the drive shaft continues through a central tube which is mounted on the end flange.
• a flexible cardan joint is present at the driving point on the reactor and adjacent the driving motor.
• a cylinder with a rectangular hole made of very tough and strong silicon nitride, is arranged to enable taking up of extra stresses during the drive of the reactor.
• another tube is arranged to extend from the first reactor end plate to the second reactor end plate, this tube having a diameter of 4 cm and a wall thickness of 0.9 cm.
• the silicon nitride plug projects slightly in order to center the intermediate flange with respect to the end plate.
• the end plate at the bottom of the rotor has a projecting ceramic cylinder in order to center the reactor with respect to the intermediate flange.
• the intermediate flange is fixed on the end flange with two pins. At the underside, these are two ceramic shearing pins. At the top these are metal pins. These metal pins are mounted in such a manner that no problems can arise due to a difference in coefficients of expansion of the ceramic and these metal pins.
• the driving motor is preferably a stepping motor.
• the transmission to the reactor occurs via a reducer and a torque limiter.
• This torque limiter is a protection against possible damage of the reactor upon jamming of the reactor.
• the stepping motor is fully controllable in power and rotational speed.
• the reactor will be rotated stepwise, whereby exactly one reactor compartment is rotated into a section and exactly one out of a section (step size 2 ⁇ /number of reactor tubes) and in the other case it will be rotated continuously.
• the stepwise operation can have as an advantage that the duration and magnitude of the variation in the gas velocity and the pressure increase that may occur if a reactor tube is temporarily closed, is minimal. The greater the number of reactor compartments per section, the lesser the variation in the gas stream and pressure during the rotation of the reactor will be.
• a section should always contain at least two reactor compartments to prevent temporary blocking of the gas stream, and hence strong pressure increase, during the rotation of the reactor rotor.
• the rotor part and the flanges were heated twice to 1273 K and the flanges were lapped onto each other so that a perfect gastight fit between the flanges was obtained.
• a spring Arranged on the end flange at the top of the reactor is a spring by means of which the pressure on the flanges can be adjusted. Upon increase of the gas pressure in the system, the pressure on the flanges will be increased to prevent gas leakage.
• the tubes are wholly or partly filled with sorbent material. If high gas velocities (> 2 m/sec) are employed, it has great advantages to use a structured carrier, such as a monolith. Moreover, a monolith is relatively insensitive to dust. This monolith consists wholly or partly of a manganese-based sorbent material. Obviously, when using the reactor for a different application than high-temperature desulfurization, a different active material will be provided on the monolith or particles.
• the reactor intermediate flanges include four sections, through which gas is supplied or discharged. In the configuration shown (see Fig.
• the two small sections discharge and supply flushing gas (flushing gas is, for instance, nitrogen or argon) .
• the two large sections serve for the supply of, respectively, 'sulfidation gas' and 'regeneration gas' and for the discharge of cleaned sulfidation gas and the regeneration off-gas.
• a typical composition of the sulfidation gas is: H 2 S 0.2-3%, H 2 0 0-4%, CO 0-50%, H 2 20-50%, C0 2 0-2%.
• Nitrogen is used as balance gas.
• Regeneration gas H 2 0 20-70% steam, in regeneration with S0 2 , 10 to 100% S0 2 . Nitrogen is used as balance gas.
• the direction of the regeneration gas is opposite to the direction of the sulfidation gas.
• a flushing gas that flushes the reactor compartments after regeneration. This flushing gas could be joined with the regeneration gas for further processing.
• Important settings and data for the proper operation of the reactor are: the concentration of H 2 S and/or COS, H 2 0, H 2 and CO in the sulfidation gas; the amount and form of the sorbent material present in reactor compartments; the desired extent of desulfurization (e.g. ⁇ 100 ppm H 2 S and COS) - the operating temperature of the reactor; the magnitude of the gas stream to be desulfurized .
• a particular speed of rotation of the reactor is chosen. Obviously, the speed of rotation can be adjusted instantaneously if changing process conditions so require.
• the composition of the sulfidation gas is (more or less) fixed under practical conditions.
• the flow and the concentration of the regeneration gas can be adjusted as desired.
• a guideline is that the sorbent material must be completely regenerated before the sorbent material leaves the regeneration section.
• a higher concentration and a higher flow of the regeneration gas will generally lead to a faster regeneration.
• a regeneration section will mostly be smaller than the sulfidation section.
• Fig. 5 shows a typical sulfidation and regeneration curve of a fixed bed reactor.
• the concentration of H 2 S in the sulfidation gas is shown (1).
• the gas containing the H 2 S is switched across the reactor.
• complete uptake of the H 2 S occurs (2).
• the sorbent bed breaks through.
• the sulfidation is stopped.
• sulfidation was continued until the feed concentration of H ? S was achieved again (3) .
• the H ? S concentration eventually present in the cleaned gas is the average H 2 S concentration from the reactor compartments in the sulfidation section (six compartments in this example).
• the H 2 S concentration of the gas leaving an individual reactor compartment may be higher than the maximum allowable H 2 S concentration in the cleaned gas. It is requisite, however, that the average H 7 S concentration of the six reactor compartments does not exceed the maximum value.
• a sorbent In comparison with a fixed bed reactor, therefore, a sorbent can be used somewhat longer by compensation of a "too high H 2 S concentration" with a lower H 2 S concentration coming from the other reactor compartments.
• Figs. 6A and 6B plot the concentration during a sulfidation and regeneration. It can be seen that the output concentration of H 2 S in the cleaned coal gas is substantially stable. The output concentration of H 2 S during regeneration exhibits a periodic character. Compared with the fixed bed process, the fluctuation in the H ? S concentration is already much less (factor of 6) . The more reactor compartments a regeneration section contains, the more constant is the H 2 S concentration leaving the regeneration section. In Fig. 7, where regeneration with a regeneration section with 25 reactor compartments is simulated, this is clearly shown. The H 2 S output concentration is virtually constant.
• the benchscale reactor shown can, at a gas velocity of 10 m/s in the monolith channels, a total pressure of 3 bar and a temperature of 1123 K, desulfurize 2.5 1/s (NPT) gas.
• NPT 2.5 1/s
• a compartment can reside in the sulfidation section for 268 seconds.
• This small-size reactor thus has the possibility of desulfu ⁇ zing about 200 m 3 gas per 24 hours, starting from the diameter of the reactor tubes.
• a rotational speed of one rotation per two minutes is a very realistic maximum rotational speed. This means, for instance: that much less sorbent will suffice, or that relatively much water may be present in the feed, or that also gas with a much higher (up to six times higher) H 2 S concentration can still be effectively desulfu ⁇ zed.
• the rotary reactor will require 60 to 120 times less sorbent material. The difference in required reactor volume between the fixed bed reactor and the rotary reactor will be of the same order of magnitude.

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• Engineering & Computer Science (AREA)
• Combustion & Propulsion (AREA)
• General Chemical & Material Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Devices And Processes Conducted In The Presence Of Fluids And Solid Particles (AREA)
• Solid-Sorbent Or Filter-Aiding Compositions (AREA)
• Industrial Gases (AREA)
• Physical Or Chemical Processes And Apparatus (AREA)

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• 1996
  • 1996-07-04 NL NL1003504A patent/NL1003504C2/nl not_active IP Right Cessation
• 1997
  • 1997-07-03 CA CA 2259938 patent/CA2259938A1/en not_active Abandoned
  • 1997-07-03 AU AU33606/97A patent/AU3360697A/en not_active Abandoned
  • 1997-07-03 EP EP97929576A patent/EP0958044A1/en not_active Withdrawn
  • 1997-07-03 WO PCT/NL1997/000379 patent/WO1998001222A1/en not_active Application Discontinuation
• 1999
  • 1999-01-04 NO NO990004A patent/NO990004L/no not_active Application Discontinuation

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