DE2419096A1 - METHOD AND DEVICE FOR AVOIDING CORROSION IN A MULTI-STAGE CONTACT ABSORPTION PROCESS FOR THE PRODUCTION OF SULFURIC ACID - Google Patents

Description

Applicant /.NH: THE RALPH M. PARSONS COMPANY
File number: New registration

The Ralph M. Parsons Company,
a company incorporated under the laws of the state of Nevada, 617 West Seventh Street, Los Angeles, California 90017 (V.St.A.)

Method and device for preventing corrosion in a multi-stage contact absorption process for the production of sulfuric acid

The invention relates to multi-stage contact absorption processes for the production of sulfuric acid, in particular a method and an apparatus for preventing corrosion in these processes.

In the past decade, many have been using the multi-stage contact absorption method Plants for sulfuric acid production designed and built. During this chemical process a sulfur dioxide is produced and oxygen-containing gas stream passed through several catalytic conversion stages to to convert a substantial portion of the sulfur dioxide it contains into sulfur trioxide; included the heat generated by the exothermic action is removed by multiple intermediate cooling.

Then the gas flow passes through an intermediate absorption stage in which the sulfur trioxide formed is removed from the Gas flow is absorbed. As an absorber medium

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Usually sulfuric acid with a concentration of 98-99 % is used. In some processes, the sulfuric acid is used at an elevated temperature in order to supply part of the heat that is required to bring the residual gas stream supplied to the subsequent conversion stages to the temperature required to initiate the catalytic reaction. After the residual gas flow has been brought to the required temperature, it is fed to the next catalytic stage or stages which convert the residual sulfur dioxide into sulfur trioxide in order to then absorb it from the gas flow; finally the remaining residual gas flow is blown off into the atmosphere.

Depending on the number of conversion and absorption levels used, extremely high overall conversion levels can be achieved. Sulfur dioxide to sulfur trioxide conversion rates of eg 99.9 % can be achieved.

One problem is the equipment and piping to recycle the gas stream from one Intermediate absorber to a so-called "cold" heat exchanger, which is used alone or in conjunction with other heat exchangers to transfer the gas flow to the inlet the next catalytic conversion stage or stages required temperature to preheat.

Due to the presence of acid mist and the condensation of sulfuric acid vapor contained in the gas stream extreme corrosion problems occur in these pipelines, both due to condensation of Sulfuric acid vapor at the inlet of the heat exchanger as well as through condensation of sulfuric acid mist Places where sulfuric acid mist eliminators operated ineffectively.

Since the gas flow leaving the intermediate absorber is in equilibrium with that in the intermediate absorber The acid used is located, it contains free sulfuric acid, which occurs on cold metal surfaces Temperatures below the dew point of sulfuric acid condenses and therefore leads to extreme corrosion problems leads.

Furthermore, sulfuric acid mist can form as a result of insufficient drying of the process air or process gas through which water vapor can react with the sulfur trioxide formed later in the process. The free particles of the acid mist, which exist as aerosol, can occur as a result of the flow turbulence fail in the pipeline to the "cold" heat exchanger and then on the inner surfaces of the heat exchanger stick where they lead to additional corrosion problems.

It is known that many by the multi-step contact absorption process working plants for the production of sulfuric acid with serious corrosion problems, e.g. in the pipelines and the "cold" heat exchangers suffer; some of these components were already in operation after 6-9 months of operation completely destroyed. This causes considerable losses both due to the destroyed components as well as the downtime required to replace the destroyed components.

So far there has been no practical solution to these problems found.

According to the invention, a method for avoiding corrosion in multi-stage contact absorption

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Plants for sulfuric acid production proposed, around the service life of the gas flow from an intermediate absorber to and through at least one heat exchanger Extend leading components to 10-15 years or more.

It has been shown that corrosion occurs in the intermediate absorber used in the process to the next to preheat the gas to its required to initiate the catalytic reaction Temperature used in heat exchangers leading to avoid pipelines when the pipelines so much external heat is supplied that the process gas flow at a temperature above the dew point of the sulfuric acid or the sulfur trioxide and water contained in the gas stream will.

If acid mist corrosion problems occur in the heat exchanger following the intermediate absorption stage, an open zone is proposed which is arranged at the inlet end of the heat exchanger and which has a volume contains relatively stagnant flowing gas at a temperature sufficient; ht, the heat exchanger surface to keep at a temperature above the condensation temperature of sulfuric acid in order to prevent the condensation of Sulfuric acid and sulfuric acid mist on the heat exchanger surfaces to prevent.

The invention is detailed below with reference to the embodiments shown in the drawings described. ; s shows:

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Fig. 1 A cross section of the from one intermediate absorber to the shell side of the next or the "Cold" heat exchanger leading pipeline with facilities for supplying external Heat in the gas stream flowing into the heat exchanger and a cross section of the calming zone in the heat exchanger, which is a hot zone forms for evaporation of sulfuric acid mist;

Fig. 2 An alternative embodiment according to Fig. 1, in which the process gas flows through the tubes of the heat exchanger.

According to the invention, a modification of the multi-stage contact absorption process for the production of sulfuric acid is provided suggested.

According to the invention, the corrosion in the pipelines is first eliminated, which the gas flow from a Intermediate absorption of the sulfur trioxide formed to a next or "cold" gas / gas heat exchanger lead, in which the gas stream is completely before being fed into a next catalytic oxidation stage or partially heated to its temperature required to initiate the catalytic oxidation.

According to the invention, measures are also proposed about the deposition or deposits of sulfuric acid around sulfuric acid mist in the heat exchanger itself eliminated by creating a stagnant or quasi-stagnant high temperature zone. The high temperature zone prevents both the condensation of sulfuric acid and the deposition of sulfuric acid mist on selected heat exchanger surfaces and thus the corrosion of these surfaces.

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The problems to be solved are from a consideration of the typical operational function of a multi-level Contact absorption sulfuric acid plant can be seen. After containing a sulfur dioxide and oxygen Gas flow has passed several catalytic conversion stages with intermediate cooling between the stages it is fed to an intermediate absorption column which contains 98-99% sulfuric acid as the absorber medium.

The sulfur trioxide formed is removed from the gas stream in the intermediate absorption column; happened after that the gas flow has a gas / gas heat exchanger in order to feed it completely or partially to one of the Conversion of the remaining sulfur dioxide into sulfur trioxide in one or more catalytic conversion stages preheat the required temperature. Finally, this is done from the remaining sulfur dioxide sulfur trioxide formed is withdrawn from the gas stream in a final absorption stage or stages.

A plant with a capacity of 1,200 t / d sulfuric acid is described as an example. she owns a pipe leading from the intermediate absorber to the next or "cold" gas / gas heat exchanger. The heat exchanger warms the gas. m after the Intermediate absorption completely or partially due to the initiation of the catalytic conversion required in the next catalytic stage or stages Temperature before.

In a system of this capacity, the pipeline will typically have a diameter of approximately 2 m and a length of about 20 m; it thereby forms an external heat exchange surface of approximately

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ο
13Om, due to the heat losses due to convection and

Radiation to the environment occur.

Under normal operating conditions, a gas quantity of approximately 2,000 Nm / min or approximately 150 t / h flows from the intermediate absorber through the pipeline. With a usual gas temperature at the intermediate ^{absorber outlet of approximately 80 °} C., an ambient temperature of 0 ^° C. and a wind speed of approximately 8 km / h in the normal to the pipeline and a specific heat of the process gas of 0.56 joule / gr, the process gas flow is dependent from other climatic conditions, such as cloud cover, time of day, night time conditions
cooled down.

Time conditions or the like to be at least 2 C or more

Under these conditions the heat losses of the pipeline itself are about 360 W / m or about 100 kW for the entire length of 20 m. The gas stream leaving the intermediate absorption column is naturally in a state of saturation with the sulfuric acid absorber. From the known state data in the saturated steam condition sulfuric located that ₂ SO ^ absorption column containing mmHg by a cooling of the gas in the pipeline to about 2 ⁰ C the vapor pressure of the sulfuric acid of 0.04 at a 98.6% H is seen to is reduced by approximately 0.035 mmHg.

That corresponds to: a reduction of a lar.tialdruckes of sulfuric acid vapor by about 0.005 mmHg.

The heat losses work in two ways; 1. as a reduction in the inherent heat of the process gas by cooling the process gas flow and

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2. as a reduction of the latent heat of evaporation through a condensation of sulfuric acid the gas phase into the liquid phase in the gas flow.

Under these conditions, about 3 kg / h of sulfuric acid can be converted from the vapor phase into the Condense the liquid phase. The sulfuric acid condenses in small drops that stick to the metallic surfaces of both the cold pipe and the heat exchanger to form a film of liquid Add sulfuric acid.

At this condensation rate, about 27 t / a of sulfuric acid condense in the pipeline and accumulate in the gas / gas heat exchanger. This sulfuric acid must first be evaporated back into the gas phase or removed through drainage connections.

However, if the sulfuric acid can condense first, liquid sulfuric acid with a concentration of approximately 98.6 % comes into contact with metallic surfaces. In sulfuric acid plants, the piping and heat exchanger tubes are usually made of carbon steel. It can be seen from the known corrosion tables for carbon steel "that the corrosion rate for 98.6% sulfuric acid is more than 0.5 mm / a at over 150 ° C. This means that the pipelines and the heat exchanger tubes under normal operating conditions are only have a very limited lifespan of about 6-8 months, since the pipes and the heat exchanger tubes usually have a wall thickness of 0.3-0.35 mm.

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To eliminate the corrosion problems caused by condensation of sulfuric acid, leads 1 and 2 show an embodiment of one according to the invention Pipeline 10 from an intermediate absorber (not shown) to a gas / gas heat exchanger 12. A heat source surrounding the pipeline 10 transfers an amount of heat to the gas flow, which is sufficient to keep the gas flow at a temperature above the dew point of the sulfuric acid.

The embodiment of the heat source shown in Fig. 1 and 2 consists of a helical spacing Pipes 14 arranged relative to one another around the pipeline 10. In an alternative embodiment The heat source consists of spaced apart around the periphery of the pipe 10 along it Axially arranged tubes. Steam, "Dowtherm" or a similar heat transport medium flows through the tubes 14. Between the tubes 14 there is a heater that is heated by the heat transport medium through the tubes 14 Air gap 16.

A reinforcement layer 18 is arranged between the tubes 14 and an outer insulating layer 20, to maintain the air gap 16. The insulating layer 20 reduces the heat requirement of the system and ensures that the air gap 16 between the tubes 14 is at an excess temperature, so that Heat flows into the gas flowing through the pipe 10.

In general, the power supplied by the heat pipes 14 is sufficient the air gap 16 between the tubes and the insulation 20 is at least about 50-100 ⁰ C.

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to keep above the average temperature of the gas flow in order to ensure a sufficient heat flow from the external heat source to the inner surface of the line carrying the process gas and thereby prevent the condensation of sulfuric acid.

In an alternative embodiment, the external heat source can instead of the tube 14 from an electrical Resistance heating consist; in a further alternative embodiment, it can simply consist of a the second pipe jacket surrounding the pipe 10, through which a heat transport medium flows.

The last-mentioned second pipe jacket is the least preferred embodiment because of the danger there is that in the event of leaks heat transport medium in the Sulfuric acid plant enters and contaminates it.

Due to the trick between the intermediate absorber column and the heat exchanger 12, a positive one Maintain heat flow in the gas stream to keep the process gas at a temperature above the dew point of the To keep sulfuric acid, both in the pipeline and in the heat exchanger 12 by condensation of Sulfuric acid prevents corrosion. This makes the lifespan both more expensive and for the operation of the multi-stage contact absorption process extended for the production of sulfuric acid important components.

Although the external heat source surrounding the pipe 10, the steady state condensation of sulfuric acid of the system is reduced, but condensation can still occur in the event of changes in the operating status of the system

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sulfuric acid and other condensable sulfur compounds occur. These operating status changes can occur during start-up or during a failure of the external heating source occur in the pipeline; for prevention, one immediately in front of the heat exchanger 12 is the periphery of the pipeline 10 surrounding barrier 19 is provided to prevent condensate flowing along the pipeline 10 to collect and prevent its entry into the heat exchanger 12. The condensate barrier 19 is a drainage connection 21 associated with a drainage valve 23, through the opening of which accumulated acid concentrate or the like. can be derived from the pipe 10.

The drainage connection 21 also serves to monitor the gas flowing through the pipeline 10. If during the operation of the system only gas escapes when the valve 23 is opened, the operator knows with certainty that the inner surface of the pipeline is dry and free of condensate; however, if liquid escapes, then this is an indication of the occurrence of condensation, which requires an additional supply of heat to the pipeline 10 in order to avoid condensation; or e is simply an indication that a BetriebszuF ¹ andsänderung occurred.

Another problem of corrosion in the pipeline or the heat exchanger is the condensation of sulfuric acid and the accumulation and condensation of sulfuric acid mist on the heat exchanger surfaces. Sulfuric acid mist is an aerosol of small sulfuric acid particles that block condensate or something similar can escape the outlet line of the intermediate absorber associated device.

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According to the invention, an improved "cold" gas / gas heat exchanger is also used, its construction the deposition of sulfuric acid and sulfuric acid mist particles on the heat exchanger surfaces and the the associated corrosion of the heat exchanger surfaces is prevented.

A typical gas / gas heat exchanger consists of a gas inlet chamber, which is a gas inlet line is connected, and a gas outlet chamber connected to a gas outlet line is. The inlet and outlet chambers are through several flow channels, e.g. through pipes or spaced plates are formed, connected to one another. The flow channels are of one with a gas supply line and one Enclosure connected to the gas outlet, which surrounds the the gas flow leads through the flow channels, in which it is surrounded by an envelope ... g around the flow channels flowing gas on ^: is heated or cooled.

Typical embodiments of these gas / gas heat exchangers are tube or plate heat exchangers.

In many processes, such as the multi-stage contact absorption process, contains - ^ items to be heated Gas flow condensable on the heat exchanger surfaces, in particular at the entry of the gas flow into the heat exchanger Components; an example, as already mentioned, is the vi., the intermediate-nab:> > About returning gas flow.

In FIG. 1, the gas flow coming from the intermediate absorber becomes the shell side of the heat exchanger 12 fed to heat with that of a catalytic

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Conversion stage coming, to exchange gas flowing through the tubes 30 of the heat exchanger.

In the embodiment according to FIG Intermediate absorber gas coming through the tubes 30 of the heat exchanger 12 to heat with that of a Conversion stage coming, to exchange through the shell side of the heat exchanger 12 guided gas.

In both embodiments, the heat exchanger consists of an outer jacket 22 and an inlet line for the gas coming from one or more conversion stages, an inlet chamber 26 either for the from a conversion stage or for the gas coming from an intermediate absorber, and an upper one Tube plate 28 over which the ends of tubes 30 are normally crimped. Via a lower tube plate 32 the lower ends of the tubes 30 are crimped to further an outlet chamber 34 with a gas outlet To form heat exchangers or catalytic conversion stages through a line AO.

In the embodiment according to FIG. 1, this occurs at a temperature of approximately 75 ° C. from the intermediate absorber escaping gas on the shell side of the heat exchanger preheated to a temperature of around 400 C, while it flows through flow channels 36 to the outlet line 38 and to the next conversion stage; it is assumed that only 1 heat exchanger is used is to preheat the gas to its required temperature to initiate the catalytic reaction. If more than 1 heat exchanger is used, the heat exchanger flow is reduced as a result the gas at a lower temperature.

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An emerging from a catalytic conversion stage gas stream having a temperature of about 480-560 ⁰ C flows through the tubes 30 of the heat exchanger 12 to transfer heat to the exiting the intermediate absorber gas and initiating a its catalytic reaction temperature of about 400 C to preheat.

Since the temperature of the gas flow entering the heat exchanger 12 from the intermediate absorber can drop below the condensation temperature of the sulfuric acid in the system, there is a risk that all sulfuric acid mist carried along as a result of flow turbulence or the like settles on the pipes 30 Un> 'the tube plate 32 is deposited or condensed, thereby causing its corrosion.

In order to rule out this risk, according to the invention, an open guide plate 42 is arranged between the tube plates 28 and 32. The guide plate 42 forms between itself and ■ r tube plate 32 a stagnant gas zone 44. Due to the high temperature of the fluid flowing through the pipes 30 the gas, the stagnant gas zone is maintained at a temperature above the condensation temperature of sulfuric acid mist of about 310 ⁰ C 44th Sulfuric acid mist contained in the gas stream condenses and falls through openings in the guide plate 42 into the zone 44; due to the high temperature ± i. In the zone 44, the sulfuric acid mist evaporates again into the gas flow, so that the deposition and entrainment of sulfuric acid mist and the associated corrosion problems in the heat exchanger 12 are avoided.

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Furthermore, the calming zone kk in connection with the pipeline 10 ensures that the sulfuric acid contained in it is always kept in the vapor state by a positive heat flow in the gas flow, so that thereby its condensation on the pipes and on the pipe plate 32 and the associated corrosion problems be avoided.

In the embodiment according to FIG. 2, the gas coming from the intermediate absorber enters the inlet chamber 2.6 in order to flow through the tubes 30. In the tubes 30 it enters into heat exchange with a through the inlet line 24 on the shell side of the heat exchanger 12 entering gas stream with a temperature of approximately 375-410 C. The exiting from the tubes 30 into the outlet chamber 34 Gas then flows through a line 40 to further absorbers or heat exchangers.

Since the tubes 30 are usually connected to the tube plates by a flanging operation, in the embodiment according to FIG. 2 there are depressions on the upper tube plate 28 in which η sulfuric acid and sulfuric acid mist can condense and collect; in the same way they can condense and accumulate on the walls of the entry chamber 26. In order to prevent this, part of the gas stream coming from the conversion stage with a temperature of approximately 375-410 C is passed through an isolated external bypass. ag - ₍ 8 or an equivalent internal bypass (not shown) fed into the zone 44, which remains filled with quasi-stagnant gas due to the influence of the baffle 42. The into the zone

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The bypass volume fed in is approximately 3 - 20 % of the total gas volume.

In an alternative embodiment, a portion of the baffle 42 is omitted so that a Electricity of high-temperature converter gas across the Pipes 30 to the outlet line 46 adjusts. However, the effect is the same, i.e. the tubes 30, the tube plate 28 and the walls of the inlet chamber are kept at a temperature which is sufficient to prevent condensation of sulfuric acid and sulfuric acid mist.

These measures according to the invention hold the upper part of the tubes 30 and in particular the tube plate 28 and the adjacent walls of the entry chamber 26 a temperature below the condensation temperature of sulfuric acid and sulfuric acid mist, so that all Sulfuric acid and all sulfuric acid mist that adhere to These surfaces could deposit, evaporated back into the gas stream coming from the intermediate absorber will. This prevents corrosion of both the tube plate 28 and the tubes 30 as well as the adjacent ones Walls of the entrance chamber 26 prevented.

Referring to FIG. P i ~ preferably the entire heat exchanger 12 t isolated to support the above-mentioned measures to Vermeii.ung corrosion.

In the embodiment according to FIG. 1, the re-evaporation; the sulfuric acid and the sulfuric acid mist carried back indirectly into the gas stream, while in the embodiment according to FIG. 2, the re-evaporation is carried out directly. By both Embodiments, however, are re-evaporation

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fhirch creates a high temperature door zone 44, which the Temperature of the parts of the heat exchanger that are normally subject to corrosion by condensation Subject to sulfuric acid or accumulation of sulfuric acid mist, raises so that it is free of corrosive Condensates kept v / ground.

Plate heat exchangers are according to the invention with the Baffle 42 equipped similar guiding devices, which between the plates on the with the Chambers connected plate sides are arranged opposite plate sides.

The improvement of the gas / gas heat exchanger according to the invention consists in creating a zone in the heat exchanger, the temperature of which is above the condensation temperature of corrosive properties due to a stream of hot process gas, for example converter outlet gas ^. parts, e.g. sulfuric acid and sulfuric acid mist, is held in order to avoid corrosion as a result of condensation or the accumulation of these corrosive components on the heat exchanger surfaces.

The invention therefore consists in the supply of external heat in a pipe from the intermediate absorber to the process gas stream containing the temperature of the residual sulfur dioxide to the Initiation of its catalytic reaction in a multi-stage contact absorption process for production of sulfuric acid required heat exchanger used to maintain the temperature of the Process gas flow to keep above the dew point of the sulfuric acid and thus the corrosion both in the Pipeline as well as in the heat exchanger to prevent.

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The invention also consists in providing a temperature above the condensation temperature zone held by sulfuric acid in the zone immediately following the intermediate absorption stage Heat exchanger to prevent the condensation of sulfuric acid mist on the heat exchanger surfaces.

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Claims (12)

Expectations Process for the production of sulfuric acid and oleum in a multi-stage contact absorption process, in which a sulfur dioxide and. Oxygen-containing process gas stream initially through several catalytic contact stages are carried out, in which sulfur dioxide is transformed into sulfur trioxide, with a Intercooling takes place next to remove the exothermic heat of the reaction is passed through at least 1 absorption column, in which the sulfur trioxide formed is added to the gas stream is withdrawn by contact with at least sulfuric acid, and then through a pipeline one Gas / gas heat exchanger is supplied, in which the gas flow at least partially to one of its Feeding into at least one additional catalytic contact stage required temperature is brought, in which the residual sulfur dioxide is converted into sulfur trioxide, which is finally is withdrawn from the gas stream before it is released into the atmosphere ^ characterized in that a positive external heat flow in from an absorption column to a heat exchanger (12) leading pipeline (10) is maintained to keep the gas flow at a temperature above the Dew point of the sulfuric acid carried along by the gas stream and thereby the sulfuric acid in the To keep the gas phase, so that corrosion of the Rohrleitunr (10) as a result of condensation of sulfuric acid is avoided on their surfaces. 409846/0778 2. The method according to claim 1, characterized in that the external heat supply by one through several pipes (14) arranged at a distance from one another and in contact with the pipeline (10) flowing heat transport medium takes place; and that the tubes (14) are so covered by a reinforcing layer (18) and an outer insulation layer (20) are surrounded that between the tubes (14) a through the heat transfer medium flowing through the tubes (14) consists of a heated air gap (16). 3. The method according to claim 2, characterized in that the air gap (16) through the through the tubes (14) The heat transfer medium flowing through the pipe (10) is approximately 50 - 100 C above the temperature flowing process gas is held. 4. The method according to any one of claims 2 or 3, characterized in that the heat transfer medium Is steam. 5. The method according to any one of claims 1-4, characterized in that the process gas stream supplied from the pipeline (10). λ is fed into the heat exchanger (12) in the vicinity of a high-temperature zone (44) arranged in the heat exchanger (12); and that the high-temperature zone (44) is kept at a temperature above the condensation temperature of sulfuric acid by a process gas stream from a conversion stage through the heat exchanger (12) in order to prevent the condensation of sulfuric acid on the heat exchanger surfaces. 409846/0 778 6. The method according to claim 5, characterized in that that in the high temperature zone (44) the gas is kept in stagnation; and. that the high temperature zone (44) by indirect heat transfer from coming from a conversion stage through the (gas / gas heat exchanger (1?) Flowing Gas is heated. 7. The method according to claim 5, characterized in that the high temperature türzone (44) directly from at least part of the coming from a conversion stage, through the Uochtemperati. _; -zone (44) flowing gas is heated. 8. The method according to claim 7, characterized in that about 3 -? O % of the total gas flow coming from a conversion stage are passed through the high-temperature zone. 9. "Heat exchanger for" carrying out the process according to one of claims 1-8 with a gas inlet chamber equipped with a gas inlet line, one gas outlet chamber equipped with a gas outlet line, several at a distance mutually arranged flow channels connecting the gas inlet chamber to the gas outlet chamber for a first gas flow from the inlet chamber to the outlet chamber and a flow channel surrounding the flow channels for a second gas flow around the ducts for the indirect heat exchange forming jacket with a gas inlet and a gas outlet in which a relatively cold corrosive containing condensable constituents Gas flow through indirect heat exchange 409846/0 778 with a high temperature gas flow to an increased Temperature is preheated, characterized by a near the inlet (10) of the relative cold gas flow in the heat exchanger (12) arranged through the high-temperature gas flow the heat exchanger (12) at a temperature above the condensation temperature of the corrosive Components held high temperature zone (44). 10. Heat exchanger according to claim 9, characterized in that aass rii-r relatively cold gas stream of at least condensable. Exit gas stream containing sulfuric acid a sulfur trioxide absorber of a multi-stage contact absorption process for manufacturing from -: is wy.feic acid; and that the high tempera door gas. rom the exit gas stream of a Sulfur dioxide is converted into sulfur trioxide. 11. Heat exchanger according to one of claims 9 or 10 for preventing condensation in the relatively cold gas stream from a first source containing condensable corrosive constituents! due to heating Γ an increased temperature eiuen high temperature gas flow from a second Source, characterized by a gas inlet chamber (26 ^ with a gas inlet line (24) for the high temperature gas flow; through a gas exit chamber (34) with a gas outlet line (40Ϊ for the indirect heat exchange with the relatively cold gas stream cooled high temperature gas stream; by several spaced apart, the gas inlet chamber (26) 409846/0778 with the gas outlet chamber (3 ^) connecting the High-temperature gas flow from the inlet chamber (26) to the outlet chamber (34) leading to flow channels (30); through one of the flow channels (30) surrounding, with a distance from the gas outlet chamber (34) arranged inlet (10) for the relatively cold gas and one downstream from the inlet (10) arranged gas outlet (38) equipped, the relatively cold gas in indirect heat exchange with that through the flow channels (30) flowing high-temperature gas-carrying jacket (22); through a between the inlet (10) for the relatively cold gas and the outlet chamber (34) at a distance from the outlet chamber (3A) and the flow channels (30) arranged between them and the gas outlet chamber (34) through a the high-temperature gas flow through the flow channels (30) to a temperature above the Koij.lensation temperature in the relatively cold Gas flow contained corrosive condensable constituents held zone (44) forming baffle (42). 12. Heat exchanger according to one of claims 9 and 10 for preventing condensation of condensable corrosive components in a relatively cold gas stream from a first source Preheating by a high temperature gas flow from a second source to an elevated temperature, characterized by one having a first gas inlet line (10) for the relatively cold gas equipped entry chamber (26); through a first gas outlet line (40) for the through indirect heat exchange with the high 4Ü8846 / U77 temperature gas flow preheated relatively cold gas equipped outlet chamber (34); by a plurality of spaced apart, the gas inlet chamber (26) with the gas outlet chamber (34) connecting, the relatively cold gas from the inlet chamber (26) into the outlet chamber (34) leading Sifrömungskanals (30); through a second gas inlet line (24) for the high temperature gas flow and a second gas outlet line (46) arranged at a distance from the second gas inlet line (24), surrounding the flow channels (30), the high temperature gas flow in indirect heat exchange with the flow channels ( 30) flowing, relatively cold gas-flowing jacket (22); and by a between the second gas inlet (24) for the high-temperature gas flow and the inlet chamber (? 6) at a distance from the inlet chamber Γ26) and the flow channels (30), between itself and the inlet chamber (26) a η treh through a bypass line ( 48) conducted part of the high-temperature gas flow at a temperature (outside the condensation temperature of the corrosive, condensable components of the baffle plate (44) forming the high-temperature zone (44) entering the inlet chamber) and the flow channels (30) (42). 4 Ü y ti 4 ¹ OI Ü 7 7 8 IS Blank page