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GB2089674A - A tubular reactor and method of heating it up - Google Patents

A tubular reactor and method of heating it up Download PDF

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Publication number
GB2089674A
GB2089674A GB8131877A GB8131877A GB2089674A GB 2089674 A GB2089674 A GB 2089674A GB 8131877 A GB8131877 A GB 8131877A GB 8131877 A GB8131877 A GB 8131877A GB 2089674 A GB2089674 A GB 2089674A
Authority
GB
United Kingdom
Prior art keywords
reactor
steam
water
mixing chamber
tubes
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB8131877A
Other versions
GB2089674B (en
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
GEA Group AG
Original Assignee
Metallgesellschaft AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Metallgesellschaft AG filed Critical Metallgesellschaft AG
Publication of GB2089674A publication Critical patent/GB2089674A/en
Application granted granted Critical
Publication of GB2089674B publication Critical patent/GB2089674B/en
Expired legal-status Critical Current

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Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J8/00Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
    • B01J8/02Chemical 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
    • B01J8/06Chemical 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 in tube reactors; the solid particles being arranged in tubes
    • B01J8/067Heating or cooling the reactor
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2208/00Processes carried out in the presence of solid particles; Reactors therefor
    • B01J2208/00008Controlling the process
    • B01J2208/00017Controlling the temperature
    • B01J2208/00106Controlling the temperature by indirect heat exchange
    • B01J2208/00168Controlling the temperature by indirect heat exchange with heat exchange elements outside the bed of solid particles
    • B01J2208/00212Plates; Jackets; Cylinders
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2208/00Processes carried out in the presence of solid particles; Reactors therefor
    • B01J2208/00008Controlling the process
    • B01J2208/00017Controlling the temperature
    • B01J2208/00106Controlling the temperature by indirect heat exchange
    • B01J2208/00168Controlling the temperature by indirect heat exchange with heat exchange elements outside the bed of solid particles
    • B01J2208/00256Controlling the temperature by indirect heat exchange with heat exchange elements outside the bed of solid particles in a heat exchanger for the heat exchange medium separate from the reactor

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Devices And Processes Conducted In The Presence Of Fluids And Solid Particles (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Abstract

A reactor comprises catalyst-containing tubes (3) which are disposed in a cooling zone (10) that is filled with cooling water, a mixing chamber (17), a duct (16) for supplying steam to the mixing chamber, a duct (18) for supplying cooling water from one end of the cooling zone to the mixing chamber, means (15) connecting the outlet of the mixing chamber to the other end of the cooling zone, and ducts (7), (9) for supplying gaseous reactants to the tubes (3) and for discharging reactor products. In order to heat up the reactor, steam is fed from duct (16) to mixing chamber (17), which is supplied at the same time through duct (18) with cooling water that has been displaced from one end, e.g. the upper portion, of the cooling zone; the heated water or a steam-water mixture leaves the mixing chamber and is forced, preferably through a plurality of conduits (15), into the other end, e.g. the lower portion of the cooling zone of the reactor. Surplus steam may be delivered from the reactor through a duct (11) to a steam drum (12). As the reactor is heated up, gas can be circulated through the catalyst tubes (3) by means of a pump (25). The gas may be nitrogen or a hydrogen- containing gas.

Description

SPECIFICATION A tubular reactor and a method of heating it up This invention relates to a tubular reactor and to a method of heating up the tubular reactor.
Tubular reactors having tubes which contain catalyst and which are surrounded by cooling water in a cooling zone are known and have been used, e.g. for the synthesis of methanol. Such reactors have been described in German Patent Specifications Nos. 1,930,702 and 2,024,301 and German Auslegeschrift No. 21 53 437, and in the Specifications of the corresponding U.S. Patents Nos. 3,897,471 and 3,962,300 and British Patent No. 1,389,709.
In such a tubular reactor, synthesis gas passed through the catalyst-containing tubes is converted under suitable pressure and temperature conditions to the desired product. As the synthesis is an exothermic reaction, energy must be continuously dissipated; this is effected by the cooling water. On the other hand, the catalyst must be maintained at a minimum temperature in order for the reactions on the catalyst to occur.
For this reason the cooling water and the catalyst must be heated up to a sufficient temperature when the reactor is started up. It is an object of the invention to permit said heating up to be effected in a simple and effective manner.
According to the present invention there is provided a method of heating up a tubular reactor, the reactor having tubes which contain catalyst and which are surrounded by cooling water in a cooling zone wherein steam is supplied to a mixing chamber, which is also supplied with cooling water that has been displaced from the one end of the cooling zone, and wherein the resulting heated water or a mixture of steam and water is forced from the mixing chamber into the cooling water disposed in the other end of the cooling zone.
As a result, the cooling water is circulated and is continuously heated. This method has the advantage that it does not require the circulation of gas through the catalyst, so that those parts of the plant which serve to handle and circulate the synthesis gas may remain out of operation during the heating-up period.
Shortly before the end of the heating-up period, gas may be passed through the tubes and may be circulated while the hot water or the steam-water mixture is still supplied to the reactor. As a result, this gas is heated and transports heat also to those parts of the plant which are disposed outside of the reactor and through which the gas is circulated.
The circulated gas preferably comprises an inert gas, such as nitrogen, which may be supplied together with hydrogen so that the catalyst in the tubes can be reduced before the synthesis reactions begin.
According to another aspect of the present invention there is provided a tubular reactor, comprising reactor tubes adapted to contain catalyst, a cooling zone surrounding said tubes and adapted to contain cooling water, ducts for supplying gaseous reactants to said tubes and for discharging reaction products therefrom, a mixing chamber, a duct for supplying steam to said mixing chamber, a duct for supplying cooling water from one end of the cooling zone of the reactor to said mixing chamber, and means connecting the outlet of the mixing chamber to the other end of the cooling zone.
Preferably, the reactor tubes are substantially vertical and a rising duct extends from the upper portion of the cooling zone constituting said one end to a steam drum provided with a steam blow-off duct incorporating a pressure regulating valve. A downpipe extends from the steam drum to the lower portion of the cooling zone constituting said other end.
The tubular reactor which is to be heated up may be used for the synthesis of methanol from a synthesis gas which contains hydrogen and oxides of carbon. The synthesis process and a copper catalyst used therein have been described in the Specifications of German Patent No. 1,930,702 and the corresponding U.S. Patent No. 3,897,471. The synthesis of methanol is effected at pressures in the range of about 15 to 100 bars at cooling water temperatures of about 200 to 3000C. In order to heat the tubular reactor, saturated steam at about 250 to 350"C is supplied as a heat transfer medium to the mixing chamber.This steam may be under a relatively low pressure at the beginning of the heating-up operation but as the temperature and pressure of the cooling water rise the steam must finally be forced into the mixing chamber under a pressure of about 30 to 150 bars. The minimum temperature for the synthesis of methanol is about 200"C. It will be understood that the present heating-up method can also be used for other reactions carried out in a water-cooled tubular reactor, provided that proper heating-up conditions as regards pressure and temperature are selected in view of the conditions required for such reactions.
When known copper catalysts are to be reduced by circulated hydrogen-containing gas before the synthesis of methanol begins, it is recommended to effect said reduction at temperatures of about 60 to 250"C. As heat is also generated by the reduction of the catalyst, it is desirable to dissipate heat by the cooling water also in this phase so that the catalyst will not be overheated.
In order to enable the invention to be more readily understood reference will now be made to the accompanying drawing, which illustrates diagrammatically and by way of example an embodiment thereof and which shows a tubular reactor and apparatus for heating it up.
Referring now to the drawing, there is shown a tubular reactor 1 comprising a pressure-resistant shell 2 and numerous internally disposed tubes 3. The reactor is divided into three sections by an upper header 4 and a lower header 5. The gas is supplied from the outside through a duct 7 to a distributing chamber 6, from which the gas is distributed to the tubes 3, which are filled with granular catalyst.
From the lower end of the tubes 3, the resulting product enters a collecting chamber 8 and is withdrawn from the latter through a product duct 9. A cooling chamber 10 filled with cooling water is diposed between the headers 4 and 5.
During normal operation of the reactor, the heat generated in the tubes 3 is dissipated by the cooling water and the steam which is formed escapes through a rising pipe 11 to a steam drum 12. The steam drum 12 is partly filled with water, which is supplied through a conduit 13, a supply manifold 14 and a plurality of branch conduits 15 to the lower portion of the cooling chamber 10. The supply manifold 14 is in the form of a horizontal ring, which surrounds the reactor; only the two cross-sections of that ring which are apparent on the sides are shown. For instance, two to eight branch conduits 15 lead from the annular supply manifold 14 to the lower portion of the cooling chamber 10.
Steam delivered under pressure from the duct 16 is used as a heat source for heating the interior of the reactor and, in particular, for heating the cooling water and the catalyst in the tubes 3. The steam is first supplied to a steam jet heater 17. Such devices are known per sue and act like a water jet pump which is followed by a steam-condensing chamber. The vacuum produced by the condensation of the steam and by the ejector action of the flowing steam causes cooling water from a conduit 18 to be sucked into the heater 17. The heated water orwater-steam mixture from the heater 17 flows through a conduit 19 to the annular supply manifold 14 and from the latter through the branch conduits 15 to the lower portion of the cooling chamber 10 in the reactor.As long as there is an adequate temperature difference between the cooling water received from the conduit 18 and the boiling point of the heated water in the conduit 19, all the steam will be condensed until it enters the reactor. Towards the end of the heating-up period, this temperature difference is so small that all the steam is no longer condensed so that a steam-water mixture enters the reactor.
The cooling water which has been displaced by the heating fluid leaves the reactor from the upper portion of the cooling chamber through the conduit 18 so that there is a rising current in the cooling chamber.
Surpius uncondensed steam flows through the duct 11 to the steam drum 12. The heating-up rate can be controlled in a simple manner if steam is blown off through the conduit 20, which incorporates a pressure regulating valve 21, while surplus water can be withdrawn through a sludge withdrawing conduit 22. There is always a communication between the steam drum 12 and the supply manifold 14 through one or more downpipes 13.
When a gas is used, this will be delivered by a duct 23 and will be supplied through the duct 7 into the system of tubes of the reactor. Heated gas flows from the tubes 3 into the collecting chamber 8 and then into the duct 9, the gas flowing subsequently through various parts of the plant, which will not be explained more in detail here and may include, e.g., a methanol separator 24. A blower 25 causes the gas to be circulated through a duct 26 back to the duct 7. The gas may comprise an inert gas, such as nitrogen, or a hydrogen containing gas for reducing the catalyst contained in the tubes 3. When the heating-up operation has been terminated, synthesis gas is supplied through ducts 23 and 7 to the catalyst.
It is apparent that the pressure in the cooling chamber 10 can be controlled by the valve 21 if the steam in the duct 16 is under an adequate pressure. The synthesis of methanol is usually effected at cooling water temperatures of about 200 to 300"C, which correspond to pressures of 15 to 100 bars in the cooling chamber.
At the beginning of the heating-up operation the pressure of the steam in the duct 16 may be lower than the operating pressure which is subsequently obtained in the cooling chamber but said steam pressure must rise during the heating-up operation above the operating pressure. The duct 16 is preferably supplied with saturated steam so that the steam condenses as completely as possible in the jet heater 17.
The invention will be further illustrated by the following Example: Example The tubular reactor shown in the drawing is heated up to the operating temperature of 230"C. The cooling chamber 10 of the reactor 1 is filled with water, which is initially at a temperature of 20"C. The reactor is used for the synthesis of methanol and comprises 4000 tubes 3 containing a known copper catalyst in a total quantity of 37 m3. During the heating-up operating, nitrogen flows through the tubes 3 and is circulated through the ducts 7,9 and 26. Steam is supplied as a heating fluid through the duct 16.
The conditions designated A in the following table were measured at the beginning of the heating-up operation. The conditions measured at the end of the heating-up operation are designated B.
Rate Pressure Temp.
kg/h bars Steam in duct 16 A 3240 40 255 B 4736 40 255 Water in conduit 18 A 110,000 2.5 20 B 20,000 24.7 220 Heating fluid at inlet of coolingchamber10 A 113,240 2.5 100 B 24,736 24.7 240 Nitrogen in duct7 A 50,000 10.3 20 B 50,000 10.3 210 Nitrogen in duct 9 A 50,000 10.0 40 B 50,000 10.0 230 The heating-up rate is about 25 C/h; the valve 21 remains closed. As the temperature in the reactor 1 increases, heating fluid at a higher rate is supplied from duct 16. In order to maintain a constant water level in the steam drum 12, surplus water is withdrawn through the conduit 22. The heating fluid at the inlet of the cooling chamber 10 consists initially of water and toward the end of the heating-up operation consists of a steam-water mixture.

Claims (12)

1. A method of heating up a tubular reactor, the reactor having tubes which contain catalyst and which are surrounded by cooling water in a cooling zone, wherein steam is supplied to a mixing chamber, which is also supplied with cooling water that has been displaced from the one end of the cooling zone, and wherein the resulting heated water or a mixture of steam and water is forced from the mixing chamber into the cooling water disposed in the other end of the cooling zone.
2. A method as claimed in claim 1, wherein surplus steam from the reactor is supplied to a water-containing steam drum, which is provided with a blow-off duct incorporating a control valve.
3. A method as claimed in claim 1 or 2, wherein the heated water or mixture of steam and water from the mixing chamber is forced into the cooling water in the reactor through a supply manifold and a plurality of branch conduits leading to the reactor.
4. A method as claimed in any one of claims 1 to 3, wherein gas is passed through the tubes and is circulated while the heated water or mixture of steam and water is supplied to said other end of the cooling zone.
5. A method as claimed in claim 4, wherein the circulated gas is nitrogen.
6. A method as claimed in claim 4 or 5, wherein the circulated gas contains hydrogen.
7. A method of heating up a tubular reactor substantially as hereinbefore described with reference to the accompanying drawing or in the foregoing Example.
8. A tubular reactor, comprising reactor tubes adapted to contain catalyst, a cooling zone surrounding said tubes and adapted to contain cooling water, ducts for supplying gaseous reactants to said tubes and for discharging reaction products therefrom, a mixing chamber, a duct for supplying steam to said mixing chamber, a duct for supplying cooling waterfrom one end of the cooling zone of the reactor to said mixing chamber, and means connecting the outlet of the mixing chamber to the other end of the cooling zone.
9. A tubular reactor as claimed in Claim 8, wherein the reactor tubes are substanUally vertical and a rising duct extends from the upper portion of the cooling zone constituting said one end to a steam drum and a downpipe extends from the steam drum to the lower portion of the cooling zone constituting said other end.
10. Atubular reactor as claimed in claim 9, wherein the steam drum is provided with a steam blow-off duct incorporating a pressure-regulating valve.
11. Atubular reactor as claimed in any one of Claims 8 to 10, wherein the tubes of the reactor contain a copper catalyst for the synthesis of methanol.
12. A tubular reactor substantially as hereinbefore described with reference to the accompanying drawing. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
GB8131877A 1980-12-24 1981-10-22 A tubular reactor and a method of heating it up Expired GB2089674B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19803049172 DE3049172A1 (en) 1980-12-24 1980-12-24 METHOD AND DEVICE FOR HEATING A TUBE REACTOR

Publications (2)

Publication Number Publication Date
GB2089674A true GB2089674A (en) 1982-06-30
GB2089674B GB2089674B (en) 1984-06-27

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ID=6120385

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GB8131877A Expired GB2089674B (en) 1980-12-24 1981-10-22 A tubular reactor and a method of heating it up

Country Status (4)

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DE (1) DE3049172A1 (en)
GB (1) GB2089674B (en)
IN (1) IN154616B (en)
MX (1) MX159106A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0987057A1 (en) * 1998-09-18 2000-03-22 Nippon Shokubai Co., Ltd. Catalytic vapor-phase oxidation method and shell-and-tube reactor
WO2004085575A3 (en) * 2003-03-24 2005-03-31 Conocophillips Co Commercial fischer-tropsch reactor
WO2006130192A1 (en) * 2005-05-31 2006-12-07 Exxonmobil Chemical Patents Inc. Reactor temperature control

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE820597C (en) * 1949-02-06 1951-11-12 Ruhrchemie Ag Process for carrying out the hydrogenation of carbons in contact ovens cooled with pressurized water

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0987057A1 (en) * 1998-09-18 2000-03-22 Nippon Shokubai Co., Ltd. Catalytic vapor-phase oxidation method and shell-and-tube reactor
US6582667B1 (en) 1998-09-18 2003-06-24 Nippon Shokubai Co., Ltd. Shell-and-tube reactor
SG134960A1 (en) * 1998-09-18 2007-09-28 Nippon Catalytic Chem Ind Catalytic vapor-phase oxidation method and shell-and-tube reactor
WO2004085575A3 (en) * 2003-03-24 2005-03-31 Conocophillips Co Commercial fischer-tropsch reactor
US7012103B2 (en) 2003-03-24 2006-03-14 Conocophillips Company Commercial fischer-tropsch reactor
WO2006130192A1 (en) * 2005-05-31 2006-12-07 Exxonmobil Chemical Patents Inc. Reactor temperature control
US7803332B2 (en) 2005-05-31 2010-09-28 Exxonmobil Chemical Patents Inc. Reactor temperature control

Also Published As

Publication number Publication date
IN154616B (en) 1984-11-17
GB2089674B (en) 1984-06-27
DE3049172A1 (en) 1982-07-29
MX159106A (en) 1989-04-20

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PCNP Patent ceased through non-payment of renewal fee