AU606084B2

AU606084B2 - Device for the heat exchange between a recycle gas leaving an nh3 converter and water

Info

Publication number: AU606084B2
Application number: AU80154/87A
Authority: AU
Inventors: Hans-Gunter Brieke; Hans-Dieter Marsch
Original assignee: Uhde GmbH
Current assignee: ThyssenKrupp Industrial Solutions AG
Priority date: 1986-12-06
Filing date: 1987-10-27
Publication date: 1991-01-31
Anticipated expiration: 2007-10-27
Also published as: EP0274006A1; CN1011540B; AU8015487A; DK165142B; NO166555C; ES2016607B3; DK165142C; NO874295D0; NO166555B; NO874295L; CN87108080A; CA1303020C; FI874517A; DE3641710A1; DK526287A; FI874517A0; DE3763820D1; EP0274006B1; JPH01200195A; ATE54746T1

Abstract

1. Apparatus for heat exchange between a recycle gas leaving an NH3 -converter and water, comprising heat exchanger tubes (11a, 11b) through which the recycle gas flows and which are gas-tightly connected to at least one tube plate (6) separating a pressure-resistant pre-chamber (5) and a heat exchanger chamber (3), wherein the pre-chamber (5) has at least one bell (10) for supplying the recycle gas and a collecting chamber surrounding the bell (10) for carrying away the cooled recycle gas, characterised in that the tube plate (6) is additionally provided with cooling bores (12) through which flows a water/steam mixture and which do not completely pass through the tube plate (6) from the heat exchanger side and which are communicated in their base regions by way of feed bores (13) with a water supply (14) through which the supplied water is fed into the heat exchanger chamber (3) by way of the cooling bores (12), and that the supply conduit to the externally cooled bell (10) is arranged in the associated outlet connection (7) of the pre-chamber (5) and the remaining annular space (9) in the outlet connection (7) has cooled recycle gas flowing therethrough.

Description

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Application Nunber; Lodged: Complete Specificatji.On-Lodged% Accepted: Lap sed: rvx amv'd;a:flts r~'cw' p Priority: Related Art: TO BE COMPLETED BY APPLICAITT Name of Applicant; tJEDE GMBH Address of Applicant: Friedrich-frde-Stx. 4600 Dortmru-id 1 FDERAL RPUBLIC OF' GEPMON Actual Inventort Hasune BPXTh1 and Hans-Dieter MAYPSCH Address for Service: ARTHUR S. CAVr' Co.,I Patent and Trade Mark Attorneysj 1 Rlfred Street, Sydney, New t It South Wales, Nastralia, 2000.

Complete Specii'ication for the invention entitled: DEVIE FOR THE HIEAT EXCIMNGE BEIWEE A IRiCY=t GAS XJENVIN AN NH 3 CONVMRTER AND WATER The folloting statem~ent is a full description. of this invention, including the best metho-. of performiing it knowin to mei- .ASC-4 9 0374k/SC "Device for the heat exchange between a recycle gas leaving an NH3 converter and water" The invention relates to a device for the heat exchange between a recycle gas leaving an NH 3 converter and water, with recycle gascharged heat exchanger tubes which have a gastight connection to at least one tube.heet separating a pressure-resistant channel from a heat exchange chamber, the c tubesheet being additionally provided with cooling bores for a S stream of water or of a water/steam mixture.

I Such a device is, for instance, known from the European C application 0 130 361 of the applicant. The tubesheet described in this connection is substantially arranged horizontally and provided at least sectionally with cooling bores which are closed towards the hot side and which are provided with an additional inner tube -o that the heat Sexchanger water is sucked into the tube by natural flow, the water vaporizes in the cooling bores, and the water/steam Smixture formed flows back to the heat exchanger.

C C C C CC Although this kind of cooling thick-walled structural elements which are hot at least on one side offers already special advantages, at least one disadvantage ensues from the fact that, in this case, the natural flow requires the structural elements to the substantially arranged in a horizontal position so as to allow the cooling water to enter the cooling bores with a safe recycle quantity, to vaporize, and to leave in form of a water/steam mixture.

2 i4 'A d invenwoS te invention 4. The basic application(s) referred to in paragraph 2 of this Declaration was/were the first from the actual invntor(s). application(s) made in a Convention country in respect of the invention the subject of the application.

Attestation or legalization19 87 notrequird. Declared at Dortmund this 22 dayof Septembe 19 87 To: U HHDE GMB H T o The Commissioner of Patents, COMMONWEALTH OF AUSTRALIA (Signature of ARTHUR S. CAVE CO.

PATENT AND TRADE MARK ATTORNEYS (ppa. Dr. Vogel) (Meynen)

SYDNEY

LtA S 4 4 '0374k/SC The object of the present invention is to provide for a solution which allows to.safely maintain the cooling even for an arrangement other than horizontal of the tubesheets, i.e.

cooling shall become effective independently from the position of installation of the tubesheet.

To overcome the prior art disadvantages, the invention provides a heat exchange apparatus for the exchange of heat between a 1 first fluid and a second fluid comprising of: Scc a heat exchange chamber having first fluid inlet and t "e outlets, the heat exchange chamber partially defined by at least one tubesheet separating the heat exchange chamber from a S second fluid inlet and/or a second fluid outlet; rC heat exchanger tubes at least partially located within the heat exchange chamber, the interiors of which are in fluid communication with the second fluid inlet and outlet, the heat exchanger tubes passing through said at least one tubesheet, Sthe at least one tubesheet having cooling bores therein Sconnected to a supply ot said first fluid external of the heat exchange chamber and which discharge into said heat exchange S' chamber.

24 2 2a i ~~jx~ 3 -_pZLe-teJ~yJaadaly..anae-,-im i-7er h-ba'3e-a-Kea-,ccnnect.ed-vi-a-feed-bore.s -to- a l- .ng w ate a-t-er-be-i-ng-'e d--o-t-he- This invention takes up the cocKing bores representing the state of the art but abandons the natural flow of the cooling water. In addition, feed bores have been provided for supplying cooling water to the base area of the cooling bores. A natural flow may, of course, also be applied for this purpose, but it is expedient to use conveying means.

On principle, quite a series of different designs of such heat exchangers are known, as shown, for instance, in DE-OS 20 07 528 or 30 22 480. In these cases, toc, a relief of the hot tubesheet has been realized by a particular synthesis gas routing.

SC C e c The cooling bores provided in the present invention must, in any case, be distributed uniformly over at least the hot area of the Stubesheet. Depending upon the design, it may, in certain cases, be sufficient to cool only particularly hot zones. Thus an embodiment cr of the invention provides for the tubesheet being equipped but sec- S tionally with cooling bores connected via feed bores to the cooling water supply line.

S' It may also be expedient to design the cooling water supply line as S branch from the feedwater supply line, i.e. part of the feedwater the heat exchanger is charged with is introduced through the cooling bores direct.

Instead of the direct connection between the feedwater supply line and the cooling water supply line, the latter may be connected to the water cycle of the steam generator, which is, of course, not excluded due to the measure mentioned before.

1 i According to a special embodiment of the invention, the channeL is of the split type having at least two recycle gas intake bells for different NH 3 converter outlet gases as well as the pertaining col- SRVPP11001Q70987

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Li. i Ir 1 i Li-:i -4lecting chambers for the cooled recycle gases. This measure conditions a particularly compact structural concept. A stepwise cooling of one and the same recycle gas at different temperature stages can also take place in a common housing.

to a further embodiment of the invention at least one of V the feed lines for the bells cooled from the outside is arranged in the pertaining outlet nozzle, the design providing for a cooled recycle gas flow through the annular space. This also contributes to 1,4 a relief of the structural elemaents, in particular to cooling the inlet nozzles of the device.

As already mentioned above, there exist quite different heat ex- C C0 changer designs. The heat exchangers may be arranged in vertical, horzonal or'nlndpsto.Te a be equipped with one tubeshet nlyandtherecclegasbeaingtubes may be designed as 1 IS lon U-hapd tbe oil, ie, hes tues tar inthetubesheet however, riot limited to this design. Thus the device invetio asl be equipped with two tubesheets and with two channels, the invention providing in such a case that the second channel, too, is split into two deflection chambers for two different N14 3 converter outlet gases and that at least one of the tubg~sheets is equipped with cooling bores. Pursuant to a further embodiment of the invention, cooling bores are at least incorporated sectionally in Sboth tubesheets.

The invention may be described more detailed as follows, with due reference to the attached drawings which show ini Fig. 1 a device for the heat exchange 1 with cooled Itubesheet, Fig. 2 a further ewbodiment with two tubesheets, at least one o them being cooled, Fig. 3 a further embodiment or the design as per Fig. 2, RVPP1 1O0lQ7Q987

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5 Fig. 4 a heat exchanger with tubes in opposed direction and with channels and deflection .chambers, each of the two tubesheets being cooled at least sectionally, Fig. 5 a further embodiment of a heat exchanger with two tubesheets which are cooled at least sectionally.

Figures 1 to 5 are sectional drawings reflecting the principle of the device, Fig. 6 a cross section of a channel of one embodiment, Fig. 7 the same representation of a channel of another embodiment, Fig, 8 C f the arrangement of bores and cooling bores in the tubesheet for an embodiment as per Fig. 6, c t Fig. 9 the bores in a tubesheet for an embodiment as per Fig. 7.

Initially it is pointed out that in all figures the same reference numbers have been used for such parts which are identical or similar in function. In some cases variations have been marked by small 'w letters.

The heat exchange device represented in the above figures consists of a pressure-resistant casing 2 with two chambers, viz. a heat exchange chamber 3 and a channel 5 split by a.partition wall into the two channel sections 5a and 5b. The channel 5 and the heat exchange chamber 3 are separated by tubesheet 6.

The special feature of the embodiment represented in the figures is that two heat exchangers are accommodated in housing 2, which requires the channel 5 to be split by a partition wall 4, It must be noted that the invention is, however, not limited to such an embodiment. The essential feature is the design of the tubesheet which is referred to below in more detail. First the basic design of the device 1 is described.

RVPP11001Q70987 ~1 i~ L l;r iy:- LYL~ -Li 6; The channel sections Sa and Sb are equipped with a nozzle 7a and 7b represented only schematically which, in turn, are provided with an inner inlet tube 8a and 8b being arranged centrally in the nozzle 7a and 7b so that an annular space 9a and 9b is produced. The inlet tube nozzles 8a and 8b lead to the hot gas chambers or bells and 1Ob which charge the tubesheet 6 sectionally. The heat exchanger tubes lla and l1b are U-shaped in the embodiment as per Fig. 1, i.e. their arrangement in the heat exchange chamber 3 is such that they start from the tubesheet, describe a bow at their upper end and then return to the tubesheet 6. The cooled gases flow back to the chainel sections Sa and 5b and are discharged via the annular space 9a and 9b. It is vhus possible to keep the tube nozzles 7a and 7b at the same low temperature as the walls of channel etc€ C CC The design of the channels as well as of the gas routing permits, Sof course, a plurality of modifications. Some variations to which the invention is, however, not limited are described below in more detail. The essential design features of the following embodiments are identical.

Particularly important for the invention is thb design of the tubesheet 6. As can be seen from the representation, the tubesheet is provided with a series of cooling bores 12 which are open towards Sthe side wall of the heat exchange chamber 3. These bores do not penetrate the tubesheet 6 completely and are interconnected in their base area via feed bores 13. The feed bores 13 are connected at the outside to a water supply line 14 which, by way of example, surrounds the device 1 as a semi-circular cooling ring The heat exchange fluid, e.g. water, for producing steam or a water/steam mixture is introduced via a feed nozzle 16 of the heat exchange chamber 3 and the heated oz vaporized fluid or a mixture of both leaves the heat exchange chamber 3 via a nozzle 17.

It is crucial ftAi the invention that the fluid cooling the tubesheet 6 is the same as the heat exchange fluid that enters the heat RVPP11001Q70987 -7 exchange chamber 3 via nozzle 16 since these fluids mix directly as desired,, the water entering via water supply line 14 being fed directly to the heat exchange chamber 3 via the cooling bcces 12.

The embodiment as per Fig. 2 shows essentially the same design of S device 1, The difference is that two tubesheets 6 and 18 have been provided, with two channels 5a and 5b and two deflection chambers 19a and 19b.

Fig. 3 shows a further embodiment with two tubesheets 6 and 18.

However, the fluid to be cooled is led without deflec tion through the heat exchange chaiber 3. In this case the channel nozzles 7a and 7b ara cooled separately by means of a cooling agent entering I'c via the tube nozzles 20a and 20b. The cooling agent may, of course, I be the process gas leaving the chambers 21a and 21b via the tube nozzles 22a and 22b, or any other fluid.

Whereas in the embodiments as per Fig. 2 and 3 only one of the two tubesheets 6 and 18 is cooled (namely tubesheet Fig. 4 shows a further embodiment with two tubesheets cooled at least sectionally.

Therefore, both tubesheets are given the reference number 6a. In this case the two heat exchangers are charged with a counter-cur- 2, rent flow in a common housing. Each of the channels Sa and Sb has its own deflection chamber 19a and 19b. Due to the special tube- Ssheet cooling, two water supply lines 14a and 14b have been pro- Svided.

Fig, 5 shows a further embodiment of a heat exchanger in horizontal 23 position. The other embodiments are, of course, also suitable for horizontal position; this is not decisive for the invention.

According to the design as per Fig. 5, the channels and deflection chambers are not of the split-type. The two gas streams charging the heat exchange chamber 3 in counter-current enter via the two hot gas inlet nozzles 8c and 8d and pass through the chambers lOc and 10d before reaching the heat exchanger tubes in the tubesheets 6b. The tubestheets 6b are cooled with water at least sectionally.

RVPPX1100Q70987 8 If the fluid is e.g. a hot recycle gas fed to the chamber lOc via tube nozzle 8c, a bypass line 23 extending through the entire heat exchanger and equipped with control facilities, if required, may additionally be provided for securing a flow through the annular space 24 around the tube nozzle 8d. This annular space 24 is cooled at its outside by the cooled process fluid traversing a surrounding annular space Fig. 6 is a cross-sectional view of a channel 5 following nearly line VI VI marked in Fig. 1. The pertinent distribution of the bores in tubesheet 6 is given in Fig. 8. It is discernible that the feed bores 13 must be relatively long to reach even the cooling bores 12 arranged centrally.

j A further embodiment is shown in Fig. 7 and 9. In this case the chambers 10a and 10b are arranged relatively close to the tubesheet periphery so that only short feed bores 13a (Fig. 9) have to be provided. This may facilitate fabrication and save costs.

The embodiments of the invention described before by way of example permit, of couree, a plurality of modifications without departing from the basic idea of the invention, As already mentioned, the invention is not necessarily limited to a cooling with water. Other fluids may be used as well. Variations as regards the cooling bores etc. art also feasible.

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Claims

1. A heat exchange apparatus for the exchange of heat between a first fluid and a second fluid comprising of: a heat exchange chamber having first fluid inlet and outlets, the heat exchange chamber partially defi:,ed by at least one tubesheet separating the heat exchange chamber from a second fluid inlet and/or a second fluid outlet; heat exchanger tubes at least partially located within the heat exchange chamber, the interiors of which are in fluid "'CC communication with the second fluid inlet and outlet, the heat "t exchanger tubes passing through said at least one tubesheet, C the at least one tubesheet having cooling bores therein connected to a supply of said first fluid external of the heat exchange chamber and which discharge into said heat exchange chamber,

2. The apparatus of claim 1 wherein, or each of the at least one, tubesheet has cooling bores over part of its area.

3. The apparatus of claim 1 or claim 2 wherein the supply is a branch from the first fluid inlet.

4. The apparatus of claim 1 or claim 2 wherein the supply is connected to the water circuit of a steam generator.

The apparatus as claimed in any one of claims 1 to 4 wherein the first fluid is water and the second fluid is recycled gas from an NH 3 converter.

6. The apparatus of any one of claims 1 to 5 wherein the second fluid inlet comprises two separate fluid inlets and the second fulid butlet comprises two separate fluid outlets for two different fluids. 9 1 P t S0374k/SC

7. The apparatus of any one of claims 1 to 6 wherein the, or at least one of the, said second fluid inlet is arranged within the corresponding second fluid outlet.

8. A heat exchange apparatus substantially as herein described with reference to the drawings. DATED this 19th day of Octobrr, 1990. UHDE GMBH By Its Patent Attorneys ARTHUR S. CAVE CO. C i' il I '1 10