CA1099484A - Process of producing sulfuric acid - Google Patents
Process of producing sulfuric acidInfo
- Publication number
- CA1099484A CA1099484A CA256,082A CA256082A CA1099484A CA 1099484 A CA1099484 A CA 1099484A CA 256082 A CA256082 A CA 256082A CA 1099484 A CA1099484 A CA 1099484A
- Authority
- CA
- Canada
- Prior art keywords
- gases
- contacting
- heat
- catalytic reaction
- interstage
- 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.)
- Expired
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B17/00—Sulfur; Compounds thereof
- C01B17/69—Sulfur trioxide; Sulfuric acid
- C01B17/74—Preparation
- C01B17/76—Preparation by contact processes
- C01B17/765—Multi-stage SO3-conversion
- C01B17/7655—Multi-stage SO3-conversion with intermediate absorption
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Treating Waste Gases (AREA)
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
- Devices And Processes Conducted In The Presence Of Fluids And Solid Particles (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Separation By Low-Temperature Treatments (AREA)
- Gas Separation By Absorption (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
The present invention relates to a contact process for producing sulfuric acid from gases containing more than 10% by volume SO2 and which gives a maximum amount of surplus heat in an economical manner and is utilized for an increase in the concentration of dilute sulfuric acids. This improved process comprises the following steps:
(a) combining the production of sulfuric acid with an in-crease of the concentration of dilute sulfuric acid;
(b) adding oxygen-containing gases to a partial stream of SO2-containing gases at such a rate that the gas mixture can be reacted at least in a first contacting tray until the reaction has pro-ceeded to an equilibrium below or at the highest temperature which is permissible for the catalyst;
(c) heating said resulting gas mixture to the operating temperature of said first contacting tray by subjec-ting it to heat exchange with hot sulphur trioxide-containing gases flowing between contacting trays;
(d) adding the remaining SO2-containing gas to the sul-phur trioxide-containing gas from at least the first contacting tray of the first catalytic reaction stage;
(e) controlling the rate at which the partial stream of SO2-containing gases is fed to, the first contacting tray so that SO3 is produced in step (b) at such a rate that the ratio of SO2:SO3 in the mixture produced in step (d) is such that the reaction in the following contacting trays can proceed to an equilibrium below or at the highest temperature which is permissible for the catalyst;
(f) removing SO3 from the catalytically reacted gases by interstage and final absorption at operating temper-atures of 100-200°C;
(g) conducting the catalytic reaction in the second cata-lytic reaction stage in at least two contacting trays and cooling the gases between the contacting trays;
(h) expelling water from the dilute sulfuric acids by directly contacting the acids with hot gases consisting of the contact process exhaust gases which have been subjected to final absorption or of inert gases having a low water content, or a mixture thereof;
(i) heating the expelling gases with at least part of the heat which becomes available in the final heat ex-changer, which follows the second catalytic reaction stage;
(j) heating the expelling gases with at least part of the heat which becomes available during the cooling of the catalytically reacted gases in step (g) or with at least part of the heat which becomes available in the second cooling stage which follows the first catalytic reaction stage and precedes the interstage absorption, or both and (k) using the heat energy derived from the acids which are circulated through at least one of the devices in the group comprising the dryer, the interstage absorber and the final absorber so as to increase the concen-tration of or to preheat the dilute sulfuric acid, or both.
The present invention relates to a contact process for producing sulfuric acid from gases containing more than 10% by volume SO2 and which gives a maximum amount of surplus heat in an economical manner and is utilized for an increase in the concentration of dilute sulfuric acids. This improved process comprises the following steps:
(a) combining the production of sulfuric acid with an in-crease of the concentration of dilute sulfuric acid;
(b) adding oxygen-containing gases to a partial stream of SO2-containing gases at such a rate that the gas mixture can be reacted at least in a first contacting tray until the reaction has pro-ceeded to an equilibrium below or at the highest temperature which is permissible for the catalyst;
(c) heating said resulting gas mixture to the operating temperature of said first contacting tray by subjec-ting it to heat exchange with hot sulphur trioxide-containing gases flowing between contacting trays;
(d) adding the remaining SO2-containing gas to the sul-phur trioxide-containing gas from at least the first contacting tray of the first catalytic reaction stage;
(e) controlling the rate at which the partial stream of SO2-containing gases is fed to, the first contacting tray so that SO3 is produced in step (b) at such a rate that the ratio of SO2:SO3 in the mixture produced in step (d) is such that the reaction in the following contacting trays can proceed to an equilibrium below or at the highest temperature which is permissible for the catalyst;
(f) removing SO3 from the catalytically reacted gases by interstage and final absorption at operating temper-atures of 100-200°C;
(g) conducting the catalytic reaction in the second cata-lytic reaction stage in at least two contacting trays and cooling the gases between the contacting trays;
(h) expelling water from the dilute sulfuric acids by directly contacting the acids with hot gases consisting of the contact process exhaust gases which have been subjected to final absorption or of inert gases having a low water content, or a mixture thereof;
(i) heating the expelling gases with at least part of the heat which becomes available in the final heat ex-changer, which follows the second catalytic reaction stage;
(j) heating the expelling gases with at least part of the heat which becomes available during the cooling of the catalytically reacted gases in step (g) or with at least part of the heat which becomes available in the second cooling stage which follows the first catalytic reaction stage and precedes the interstage absorption, or both and (k) using the heat energy derived from the acids which are circulated through at least one of the devices in the group comprising the dryer, the interstage absorber and the final absorber so as to increase the concen-tration of or to preheat the dilute sulfuric acid, or both.
Description
1()99484 ~his invention relates to a process of producing sulfuric acid which comprises catalytically reacting S02 to form S03 in gases which contain more than 10% by volume S02 and which have been cooled, purified and dried before being fed to the catalytic reaction system, heati.ng purified S02-co.ntaining gases to the operating temperature of the first contacting tray by a heat exchange with S03-containing hot gases which flow between contacting trays and which are cooled by said heat exchange to the aperati.ng temperature of the next following contacting tray, subjecting the S03 which has been formed in a plurality of contacting trays of a first catalytic reaction stage to interstage absorption in sulfuric acid at elevated temperature, subjecting the S03-containing gases which leave the first catalytic reaction stage to cooli.ng in two stages before the gases are subjected to interstage absorptio.n, reheating i.n the first cooling stage the gases which leave the interstage absorptio.n system to the operating temperature of the next following contacting tray, subjecting the gases which have been completely catalytically reacted in the second catalytic reaction stage to cooling in a final heat exchanger whereby heat is recovered which is not required in the catalytic reaction : system, and absorbing in a final absorber the S03 which has been produced in the second catalytic reaction stage.
Dilute sulfuric acids, which may also contain impuri-ties, become available i.n numerous chemical processes. A dis-carding of such acids into rivers or coastal waters must be increa~singly restricted for ecological reasons and involves considerable transportation costs. ~ven higher transportation costs are incurred when the acids are discarded into the sea.
~or the reasons stated above, these dilute acids must be suitably processed to form products which are reusable or innocuous or to reduce the weight and volume to be transported.
~ ' 1~99~89~
~his processing becomes progressively more urgent also for the recovery of raw materials.
The processing of the dilute acids comprises generally an increase in concentration and possibly a thermal decomposition.
In both cases, water must be stripped from the dilute acids at considerable rates. ~Ieat at the high rates which are required for this purpose involves high operating costs, particularly when expensive primary energy must be used or heat ener~y ~hich is at a high temperature and could be economical]y utilized for other purposes, e.g., for producing steam.
The Printed German Application 1,186,838 discloses a process in which gases which contain more than 9 % S02 are purified, dried, catalytically reacted in a first catalytic reaction stage, then subjected to interstage absorption at elevated temperature to remove SO~, completely catalytically reacted in a second catalytic reaction stage, and subjected to a final absorption to remove the remaining S03. After the first catalytic reaction stage, the S03-containing gases are cooled in two stages. The gases leaving the interstage absorption system are heated in the first cooling stage to the operating temperature of the next contacting tray. Heat which is not required in the contact process system may be dissipated in the second cooling stage or in the final heat exchanger.
German Patent Specification 1,567,672 discloses a process in which gases which contain 8-11% S02 and become available at elevated temperature are also cooled in two stages before being subaected to interstage absorption. ~Ieat which is not - required in the contact process system can be recovered in the second cooling stage and in the final heat exchanger, which succeeds the last contacting tray.
Opened German Specification 2,307,973 discloses a process in which a partial stream of gases containing a high 1~3994~il4 percentage of S02 is mixed with o~gen-containing gases to provide a mixture which can be reacted to aD equilibrium in the first contacting -tray below or at the highest permissible temperature of the catalyst. The S03-containing gas stream which leaves the first contacting tray is mixed before the second contacting tray with the remaining S02-containing gas. Owing to the S03 content of the mixture, the equilibrium is attained in the second contacting tray also before a detrimental temperature in reached.
It is known from Open German Specification 2,1~5,546 1o to treat contact process ex~aust gases with dilute sulfuric acid in order to remove S03 and sulfuric acid mists. The dilute sulfuric acid may be increased i.n conce.ntration. The co.ntact process exhaust gases may be heated.
It is an object of the invention to recover as much surplus heat as possible in an economical manner from the co.ntact process system and to utilize the heat which has been recovered for an increase of the concentration of dilute sulfuric acids.
~his object is accomplished in accordance with the invention by the combination of the following steps:
a) The production of sulfuric acid is combined with an i.ncrease of the concentration of dilute sulfuric acid;
b) Oxyge.n-contai.ning gases are admixed at such a rate to a partial stream of S02-contain~ng gases that the gas mixture can be reacted at least i.n a first contactiDg tray until the reaction S02 + l/2 2 = S03 has proceeded to an equilibrium below or at the highest temperature which is permissible for the catalyst;
c) The gas mixture is subjected to a heat exchange with S03-containing hot gases flowing between contacting trays and is thus heated to the operating temperature of the first contacting tray;
` 11~99484 `;
d) The S03-containing gas from at least the first co.ntacting tray is mixed with the remaining S02-containing gas and the resul~,ing mixture is fed to a further contacting tray of the first catalytic reaction stage;
e) The rate at which the partial stream of S02-containing gases is fed to the first contacting tray is controlled so that S0~ is produced in step b) at such a rate that the ratio of S02:S03 in the mixture produced in step d) is such that the reaction in the succeeding contacting trays can proceed to a~ equilibrium below or at the highest temperature which is permissible for the catalyst;
f) S03 is removed from the catalytically reacted gases by interstage and final absorption at operating temperatures of 100-200C, preferably 110-160C;
g) The catalytic reaction i.n the second catalytic reaction stage is carried out in at least two contacting trays and the gases are cooled between the contacting trays;
. h) Water is expelled from the dilute sulfuric acids by .~ 20 directly contacting the latter with hot gases consisting of the contact Process exhaust gases which-have been . subjected to final absorption and/or of inert gases . having a low water content; .
i) The expelli.ng gases are heated with at least part of the heat which becomes available in the final heat exchanger, which succeeds the second catalytic reaction stage;
j) The expelling gases are heated with at least part of the heat which becomes available during the cooling of the catalytically reacted gases in step g) and/or with at least part of the heat which becomes available in the second cooling stage which succeeds the first .
1~99484 catalytic reaction stage and precedes the interstage absorption; and k) The heat energy derived from the acids which are circulated through the dryer and/or the interstage absorber and/or the final absorber is used to increase the concentration of and/or to preheat the dilute sulfuric acid.
The gas mixture consisting of the oxygen-containing gas and the partial stream of SO2-containing gas may be passed through a single contacting tray or through a plurality of series-connected contacting trays before said mixture is admixed to the remaining SO2-containing gas. When the mixture is passed through a plurality of contacting trays, the gas is cooled between the contacting trays by a heat exchange with SO2-containing gases or with a mixture of SO2-containing gases and oxygen-containing gases added thereto. The oxygen-containing gas consists generally of air oxygen-enriched air. The oxygen required for the entire conversion is preferably admixed to the partial stream of SO2-containing gas before the first contacting tray. Alternatively, oxygen is added only at the rate required to control the reaction in the first contacting tray, and the remainder is added at a succeeding point of the contact process system. The first catalytic reaction stage consists of two to three contacting trays. The second catalytic reaction stage consists generally of two contacting trays. Whereas more contacting trays may be used, this will not afford any advantages. If the final heat exchanger succeeding the last contacting tray consists of a single stage, the entire heat exchanger will be used to heat expelling gases. If this heat exchanger consists of two stages, which are connected in series or parallel, one of said two stages will be used to heat the expelling gases. The expelling gases are heated further either in the second cooling stage succeeding the ~ A ' --1(~99484 first catalytic reaction stage and preceding the interstage absorption, or in the heat exchanger which is connected between the contacting trays of the second catalytic reaction stage. Depending on the selected mode of operation, the other heat exchanger is used to heat a mixture of S02-containing gases and oxygen-containing gases.
- 5a -~(~994 ;
In the second cooling stage, which precedes the interstage absorption, the S03-containing gases from the first cata]ytic reaction stage are preferably cooled to l-~0-200C. ~etween the second catalytic reaction stage and the final absorber, the S03-containing gases are preferably cooled also to 130-200C.
A preferred ~urther feature resides in that the remaining S02-containing gas is admixed in step (d) at such a rate that the resulting mixture is at a gas temperature which corresponds to the operating temperature of the next following contacting tray. In this case a heat exchanger is not required there.
A preferred further feature resides in that the oxygen-oontaining gases are separately dried with sulfuric acid before being fed to the catalytic reaction vessel. As a result, the heat which is generated by the drying of the o~Yygen-containing ~ -gases can be carried off by the gases and the acid used in the dryer can be recirculated without being cooled. The heat which is thus carried off by the gas is thus supplied to the contact process system. Alternatively, the partial stream of S02- -containing gases may be added to the oxygen-containing gases before they enter the dryer, although the advantage described hereinbefore is sacrificed in this case.
According to a further preferred feature, the oxygen-containing gases and/or the S02-containing gases are dried at elevated temperatures and are at a temperature of 60 80C, preferably 65-70~C, when leaving the dryer. In this case, the gases carry heat into the contact process system, and the heat of the acid becomes available at a higher temperature and can be utilized.
~ccording to a further preferred feature, the mixture of the partial stream of S02-containing gases and the oxygen-containing gases added thereto in step b) is handled by a blower.
-- 6 _ 1099~84 In that case, the remaining partial stream of SO2-containing gas -may be handled by a blower which is small and delivers at a lower pressure so that lower operating costs are involved in the handling of the gases in the contact process system.
A further preferred feature resides in that the oxygen-containing gases are handled by a blower before they are added in step b) to the partial stream of SO2-containing gases. Whereas the advantage described hereinbefore is sacrificed in this case, the two blowers may have approximately the same design on the pressure side so that the expenditure involved in the blowers is reduced, only one spare blower is required, and less spare parts are to be kept in stock. This feature will be adopted if the saving in operating costs is smaller than the savings described.
According to a further preferred feature, the drying and/or interstage absorption and/or final absorption is effected at least in part as a cocurrent operation in Venturi-tube absorbers.
This results in high exit temperatures of the gases and acid.
The invention will be explained in a non limiting way with referrence to the following examples and the appended drawing wherein:
- fig. 1 shows the contact process of example 1 - fig. 2 shows the contact process of example 2 - fig. 3 shows the contact process of example 3 The contact process system shown in Fig. 1 is designed 1~3g94~4 for a production of about 1000 metric tons of S03 per day from gases which contain about 28.4.% by volume S02, about 3.86% by volume 2~ balance N2+C02, and have been produced by a decomposi-tion of sulfuri.c acid and/or sulfates.
About 40,830 standard m3/h S02-contai.ning gas, which contains about 56 g water per standard m3, are sucked by a blower 12a through duct 1, Venturi tube 2, duct 3, spray tower 3b and spray separator 4 and are dried by means of ~2S04 in a concentra-tion of about 96% and then co.nducted in duct 11 at a temperature of about 65C. ~he acid used in the dryer is circulated through conduit 5, cooler 6, conduit 7, pump 8, and co.ndu~t 9, and through conduit 9y to no~zle 10 and through conduit 9x to nozzle lOf.
About 54,170 standard m3/h atmospheric air, which contains about 20 g water per standard m3, are sucked by a blower 12 through duct la, Venturi tube 2a, duct 3a, spray separator 4a and are dried by means of H2S04 in a concentration of about 96%
by weight and then conducted through duct llb at a temperature of about 65C. The acid used in the dryer is circulated through conduit 5c, pump 8c, conduit 9c, c~.onduit 9~ and nozzle lOc.
27,180 standard m3/h of gas which contains 28.43% S02 by volume are conducted through duct lla and admixed to the total air stream. 81,350 standard m3/h of gas which contains about 9.5~0 by volume S02 and about 15.14% by volume 2 are delivered by a blower 12 through ducts 13, 14, 15, 16, 17, 18, and 20 to a first contacti.ng tray 21a of a catalytic reactio.n vessel 21.
~he gases are preheated from about 90C to about 200C in a::heat exchanger 27 and from about~200C to about 435,C i.n two heat ex-changers 23a and 23 by a heat exchange with the S03-co.ntaini.ng gases. ~3,650 standard m3/h of gas which co.ntains S02 in a high percentage (about 28.43% by volume of S02, abou-t 3.86~o by volume f 2' balance N2~C02) are sucked by the blower 12a through duct ~le and delivered through duct 13a and admixed to the gases which 1~994l94 have bee.n partly catalytically reacted in the contacting tray 21a so that the S03-containing gase~ from the contacting tray 21a are cooled from about 617C to about 540C The S03-containing gases are conductcd through duct 22, heat exchanger 23 and duct 24 to a co.ntacting tray 21b and enter the same at about 450C.
: The gases which have been catalytically rcacted further in contact-i.ng tray 21b leave the same through conduit 22a at a temperature of about 570C and are cooled to about 460C i.n a heat exchanger 23a and conducted to a contacting tray 21c through duct 24a.
About 89,930 standard m~/h of S03-containing gases at about 507C are co.nducted through duct 25 to an interstage heat exchanger 26 and are cooled therein to about 280C (at 26a) by a heat exchange with the gases which have been subjected to absorp-tion. The cooled gases are then cooled further to about 190C in a heat exchanger 27 and are then fed through duct 28 to a Venturi-tube interstage absorber 29. About 79,100 standard m3/h of gases from which almost all S03 has been removed are conducted through duct 30 and spray separator 31 and leave the interstage absorption system through duct 32 at about 140C.
The highly concentrated absorber acid which co.ntains H2S04 in a high conce.ntration of about 98.5-99.0% by weight is circulated through conduit 5a, cooler 6a, co.nduit 7a, pump 8a, conduit 9a, and nozzle lOa.
The gases are fed through duct 32 to the heat exchanger 26 and at about 440C are fed through duct 33 to a contacting tray 21d and leave the same at abou-t 482C through duct 34. The gases ~hich have been catalytically reacted further are cooled to about 420C in a heat exchanger 35 and are fed through duct 36 to a contacting tray 21e. About 78,590 standard m3/h of completely catalytically reacted gases at about 422C leave the catalytic reaction vessel 21 through duct 37 and are cooled to about 180C
in a heat exchanger 40 and are fed through conduit 41 to a Venturi _ g _ 1~99~84 tube final absorber 42. About 77,485 standard m3/h contact process exhaust gas are withdrawn from the final absorber 42 through duct 43, spray separator 44, and duct 45.
~ he absorber acid which contains H2S04 in a high concentration ol about 98.5-99.0~ by weight is circulated through co.nduit 5b, cooler 6b, co.nduit 7b, pump 8b, conduit 9b, conduit 9z, and.nozzle lOb. The circulated acids are adjusted to -the optinum acid concentration which is required in that acid is exchanged through conduits 9e, 9k, 9d, and 9i and additional water required for dilutio.n is added through conduits 9f and 9h. Product which contains about 96~ by volume H2S04 is discharged through co.nduit 9g.
Contact process exhaust gases which are virtually free from water ~apor and at about 110C are co.nducted through duct 45, heat exchanger 40, co.nduit 46, and heat exchanger 35 and are thus preheated to about 420C and through co.nduit 46a are fed to a system (not sho~n) for increasing the concentration of dilute acid with utilizatio.n of the heat conte.nt of the gases.
EXAMP.~E 2 The contact process system shown i.ln ~ig. 2 differs from ~xample 1, ~ig. 1, as follows:
a) Gas duct lla is co.nnected to the pressure side of blower 12a rather than to the suction side of blower 12 so that the blower 12 must handle o.nly 54pl70 standard m3/h dried air rather than 81,350 standard m3/h mixed gases and the blower 12a must handle 40,830 standard m3/h highly co.ncentrated S02 gas rather than '.
13,650 standard m3/h highly concentrated gas;
b) Only the heat exchanger 40 is used to preheat the contact process exhaust gases. ~hese are preheated in the heat exchanger 40 from about 110C to about 340C and are then fed .
through duct 46 to a stage (not show.n) for increasing the co.ncentra-tio.n of dilute acid.
1()99~84 c) The heat exchanger 35 is used to preheat atmospheric air~ Air at the rate of about 62,285 standard m3/h which is required to entrain water vapor for a stage (not shown) for increas-ing the concentration of dilute acid is fed through duct 47 at about 30C to the he~t exchanger 35 and is preheated therein to about 115C and is the.n fed through conduit 46a to a stage (not shown) for increasing the co.ncentration of dilute acid.
EXAMP_E 3 The contact process system shown i.n Fig. 3 is designed for a production of about 1000 metric tons of S03 per day from gases which contain about 17.0% by volume of S02, about 1.50 by volume 2' balance N2~C02, and have been produced by the decomposition of sulfuric acid and/or sulfates.
About 67,430 standard m3/h dried gas which contains about 17.0~ by volume S02 and is at about 65C are sucked by a ~`
blower 12a through duct lle. About 63,570 standard m3th dried air at about 65C are sucked by a blower 12 through duct llc.
53,900 standard m3/h of gas which contains about 17.0% by volume S2 are fed through duct lla and admixed to the total air stream.
~he resulti.ng gas mixture contains about 7.8% by volume S02 and about 1200~o by volume 2 and is fed at a rate of 117,470 standard m3/h through ducts 13, 14, 15, 16, 17, 18, and 20 to a first contacti.ng tray 21a of a càtalytic reaction vessel 21~ ~hese gases are preheated from about 90C to about 260C i.n a heat exchanger 40 and from about 260C to about 440C in two heat exchangers 23 and 35 by a heat exchange with S03-containing gases. 13,530 standard m3/h gas which contai.ns about 17.0% by volume S02 and is at about 90C are conducted through duct 13a and admixed to the S03_containing gases which have been partly catalytically reacted in contacting tray 21a and which are thus cooled from 610C to about 550C. ~he S03-containing gases are onducted through a duct 22 and the heat exchanger 23 and are 1099~84 then fed at a temperature of about 450C to a contacting tray 21b.
~ bout 126,240 standard m3/h S03-containing gases at about 527C are fed through conduit 25 -to an interstage heat exchanger 26 and are cooled therein to abou.t 277C (at 26a) by a heat exchange with the gases that have been subjected to absorptio.n. The cooled gases are cooled further to about 185C
in a heat exchanger 27 and are then fed through duct 28 to a Venturi tube interstage absorber 29, ~lhich is fed through conduit 9g with acid that is sprayed through nozzle lOa.
About 116,570 standard m3/h of gases from which almost all S03 has bee.n removed are conducted through duct 30 and spray separator 31 and leave the interstage absorption system through duct 32 at about 140C and are then fed to heat exchanger 26 and thereafter at about 430C through duct 33 to a contacting tray 21d. Gases at about 470C leave the contacting ~ray 21d through duct 34 and are cooled to about 420C in the heat exchanger 35 and then fed through duct 36 to a co.ntacting tray 21e. About 115,820 standard m3/h of gases which have been completely catalytically reacted and are at about 422C leave the catalytic reaction vessel 21 through duct 37 and are cooled to about 255C ; .
in heat exchanger 40 and then fed through duct 37a to a heat exchanger 40a, in which the gases are cooled to about 180C before they are fed through duct il to the final absorber.
About 50,000 standard m3/h atmospheric air at about 30C are fed through duct 45 to the heat exchanger 40a and are pre-heated therein to about 210C and are then fed through duct 46 to a stage (not shown) for i.ncreasi.ng the co.ncentration of dilute acid.
About 100,000 standard m3/h of atmospheric air at about 30C are fed through duct 47 to the heat exchanger 27 and are preheated therein to about 160C and are then fed through duct 46a to a stage (not shown) for i.ncreasing the conce.ntration of dilute acid.
The advantages of the inventio.n reside mainly in that :
99~84 surplus heat from the contact process system, inclusive of heat which becomes available at relatively low temperature, can be economically used to increase the co.ncentration of dilute sulfuric acids so that the consumption of expensive primary energy or the use of heat at high temperature can be avoided or reduced.
Dilute sulfuric acids, which may also contain impuri-ties, become available i.n numerous chemical processes. A dis-carding of such acids into rivers or coastal waters must be increa~singly restricted for ecological reasons and involves considerable transportation costs. ~ven higher transportation costs are incurred when the acids are discarded into the sea.
~or the reasons stated above, these dilute acids must be suitably processed to form products which are reusable or innocuous or to reduce the weight and volume to be transported.
~ ' 1~99~89~
~his processing becomes progressively more urgent also for the recovery of raw materials.
The processing of the dilute acids comprises generally an increase in concentration and possibly a thermal decomposition.
In both cases, water must be stripped from the dilute acids at considerable rates. ~Ieat at the high rates which are required for this purpose involves high operating costs, particularly when expensive primary energy must be used or heat ener~y ~hich is at a high temperature and could be economical]y utilized for other purposes, e.g., for producing steam.
The Printed German Application 1,186,838 discloses a process in which gases which contain more than 9 % S02 are purified, dried, catalytically reacted in a first catalytic reaction stage, then subjected to interstage absorption at elevated temperature to remove SO~, completely catalytically reacted in a second catalytic reaction stage, and subjected to a final absorption to remove the remaining S03. After the first catalytic reaction stage, the S03-containing gases are cooled in two stages. The gases leaving the interstage absorption system are heated in the first cooling stage to the operating temperature of the next contacting tray. Heat which is not required in the contact process system may be dissipated in the second cooling stage or in the final heat exchanger.
German Patent Specification 1,567,672 discloses a process in which gases which contain 8-11% S02 and become available at elevated temperature are also cooled in two stages before being subaected to interstage absorption. ~Ieat which is not - required in the contact process system can be recovered in the second cooling stage and in the final heat exchanger, which succeeds the last contacting tray.
Opened German Specification 2,307,973 discloses a process in which a partial stream of gases containing a high 1~3994~il4 percentage of S02 is mixed with o~gen-containing gases to provide a mixture which can be reacted to aD equilibrium in the first contacting -tray below or at the highest permissible temperature of the catalyst. The S03-containing gas stream which leaves the first contacting tray is mixed before the second contacting tray with the remaining S02-containing gas. Owing to the S03 content of the mixture, the equilibrium is attained in the second contacting tray also before a detrimental temperature in reached.
It is known from Open German Specification 2,1~5,546 1o to treat contact process ex~aust gases with dilute sulfuric acid in order to remove S03 and sulfuric acid mists. The dilute sulfuric acid may be increased i.n conce.ntration. The co.ntact process exhaust gases may be heated.
It is an object of the invention to recover as much surplus heat as possible in an economical manner from the co.ntact process system and to utilize the heat which has been recovered for an increase of the concentration of dilute sulfuric acids.
~his object is accomplished in accordance with the invention by the combination of the following steps:
a) The production of sulfuric acid is combined with an i.ncrease of the concentration of dilute sulfuric acid;
b) Oxyge.n-contai.ning gases are admixed at such a rate to a partial stream of S02-contain~ng gases that the gas mixture can be reacted at least i.n a first contactiDg tray until the reaction S02 + l/2 2 = S03 has proceeded to an equilibrium below or at the highest temperature which is permissible for the catalyst;
c) The gas mixture is subjected to a heat exchange with S03-containing hot gases flowing between contacting trays and is thus heated to the operating temperature of the first contacting tray;
` 11~99484 `;
d) The S03-containing gas from at least the first co.ntacting tray is mixed with the remaining S02-containing gas and the resul~,ing mixture is fed to a further contacting tray of the first catalytic reaction stage;
e) The rate at which the partial stream of S02-containing gases is fed to the first contacting tray is controlled so that S0~ is produced in step b) at such a rate that the ratio of S02:S03 in the mixture produced in step d) is such that the reaction in the succeeding contacting trays can proceed to a~ equilibrium below or at the highest temperature which is permissible for the catalyst;
f) S03 is removed from the catalytically reacted gases by interstage and final absorption at operating temperatures of 100-200C, preferably 110-160C;
g) The catalytic reaction i.n the second catalytic reaction stage is carried out in at least two contacting trays and the gases are cooled between the contacting trays;
. h) Water is expelled from the dilute sulfuric acids by .~ 20 directly contacting the latter with hot gases consisting of the contact Process exhaust gases which-have been . subjected to final absorption and/or of inert gases . having a low water content; .
i) The expelli.ng gases are heated with at least part of the heat which becomes available in the final heat exchanger, which succeeds the second catalytic reaction stage;
j) The expelling gases are heated with at least part of the heat which becomes available during the cooling of the catalytically reacted gases in step g) and/or with at least part of the heat which becomes available in the second cooling stage which succeeds the first .
1~99484 catalytic reaction stage and precedes the interstage absorption; and k) The heat energy derived from the acids which are circulated through the dryer and/or the interstage absorber and/or the final absorber is used to increase the concentration of and/or to preheat the dilute sulfuric acid.
The gas mixture consisting of the oxygen-containing gas and the partial stream of SO2-containing gas may be passed through a single contacting tray or through a plurality of series-connected contacting trays before said mixture is admixed to the remaining SO2-containing gas. When the mixture is passed through a plurality of contacting trays, the gas is cooled between the contacting trays by a heat exchange with SO2-containing gases or with a mixture of SO2-containing gases and oxygen-containing gases added thereto. The oxygen-containing gas consists generally of air oxygen-enriched air. The oxygen required for the entire conversion is preferably admixed to the partial stream of SO2-containing gas before the first contacting tray. Alternatively, oxygen is added only at the rate required to control the reaction in the first contacting tray, and the remainder is added at a succeeding point of the contact process system. The first catalytic reaction stage consists of two to three contacting trays. The second catalytic reaction stage consists generally of two contacting trays. Whereas more contacting trays may be used, this will not afford any advantages. If the final heat exchanger succeeding the last contacting tray consists of a single stage, the entire heat exchanger will be used to heat expelling gases. If this heat exchanger consists of two stages, which are connected in series or parallel, one of said two stages will be used to heat the expelling gases. The expelling gases are heated further either in the second cooling stage succeeding the ~ A ' --1(~99484 first catalytic reaction stage and preceding the interstage absorption, or in the heat exchanger which is connected between the contacting trays of the second catalytic reaction stage. Depending on the selected mode of operation, the other heat exchanger is used to heat a mixture of S02-containing gases and oxygen-containing gases.
- 5a -~(~994 ;
In the second cooling stage, which precedes the interstage absorption, the S03-containing gases from the first cata]ytic reaction stage are preferably cooled to l-~0-200C. ~etween the second catalytic reaction stage and the final absorber, the S03-containing gases are preferably cooled also to 130-200C.
A preferred ~urther feature resides in that the remaining S02-containing gas is admixed in step (d) at such a rate that the resulting mixture is at a gas temperature which corresponds to the operating temperature of the next following contacting tray. In this case a heat exchanger is not required there.
A preferred further feature resides in that the oxygen-oontaining gases are separately dried with sulfuric acid before being fed to the catalytic reaction vessel. As a result, the heat which is generated by the drying of the o~Yygen-containing ~ -gases can be carried off by the gases and the acid used in the dryer can be recirculated without being cooled. The heat which is thus carried off by the gas is thus supplied to the contact process system. Alternatively, the partial stream of S02- -containing gases may be added to the oxygen-containing gases before they enter the dryer, although the advantage described hereinbefore is sacrificed in this case.
According to a further preferred feature, the oxygen-containing gases and/or the S02-containing gases are dried at elevated temperatures and are at a temperature of 60 80C, preferably 65-70~C, when leaving the dryer. In this case, the gases carry heat into the contact process system, and the heat of the acid becomes available at a higher temperature and can be utilized.
~ccording to a further preferred feature, the mixture of the partial stream of S02-containing gases and the oxygen-containing gases added thereto in step b) is handled by a blower.
-- 6 _ 1099~84 In that case, the remaining partial stream of SO2-containing gas -may be handled by a blower which is small and delivers at a lower pressure so that lower operating costs are involved in the handling of the gases in the contact process system.
A further preferred feature resides in that the oxygen-containing gases are handled by a blower before they are added in step b) to the partial stream of SO2-containing gases. Whereas the advantage described hereinbefore is sacrificed in this case, the two blowers may have approximately the same design on the pressure side so that the expenditure involved in the blowers is reduced, only one spare blower is required, and less spare parts are to be kept in stock. This feature will be adopted if the saving in operating costs is smaller than the savings described.
According to a further preferred feature, the drying and/or interstage absorption and/or final absorption is effected at least in part as a cocurrent operation in Venturi-tube absorbers.
This results in high exit temperatures of the gases and acid.
The invention will be explained in a non limiting way with referrence to the following examples and the appended drawing wherein:
- fig. 1 shows the contact process of example 1 - fig. 2 shows the contact process of example 2 - fig. 3 shows the contact process of example 3 The contact process system shown in Fig. 1 is designed 1~3g94~4 for a production of about 1000 metric tons of S03 per day from gases which contain about 28.4.% by volume S02, about 3.86% by volume 2~ balance N2+C02, and have been produced by a decomposi-tion of sulfuri.c acid and/or sulfates.
About 40,830 standard m3/h S02-contai.ning gas, which contains about 56 g water per standard m3, are sucked by a blower 12a through duct 1, Venturi tube 2, duct 3, spray tower 3b and spray separator 4 and are dried by means of ~2S04 in a concentra-tion of about 96% and then co.nducted in duct 11 at a temperature of about 65C. ~he acid used in the dryer is circulated through conduit 5, cooler 6, conduit 7, pump 8, and co.ndu~t 9, and through conduit 9y to no~zle 10 and through conduit 9x to nozzle lOf.
About 54,170 standard m3/h atmospheric air, which contains about 20 g water per standard m3, are sucked by a blower 12 through duct la, Venturi tube 2a, duct 3a, spray separator 4a and are dried by means of H2S04 in a concentration of about 96%
by weight and then conducted through duct llb at a temperature of about 65C. The acid used in the dryer is circulated through conduit 5c, pump 8c, conduit 9c, c~.onduit 9~ and nozzle lOc.
27,180 standard m3/h of gas which contains 28.43% S02 by volume are conducted through duct lla and admixed to the total air stream. 81,350 standard m3/h of gas which contains about 9.5~0 by volume S02 and about 15.14% by volume 2 are delivered by a blower 12 through ducts 13, 14, 15, 16, 17, 18, and 20 to a first contacti.ng tray 21a of a catalytic reactio.n vessel 21.
~he gases are preheated from about 90C to about 200C in a::heat exchanger 27 and from about~200C to about 435,C i.n two heat ex-changers 23a and 23 by a heat exchange with the S03-co.ntaini.ng gases. ~3,650 standard m3/h of gas which co.ntains S02 in a high percentage (about 28.43% by volume of S02, abou-t 3.86~o by volume f 2' balance N2~C02) are sucked by the blower 12a through duct ~le and delivered through duct 13a and admixed to the gases which 1~994l94 have bee.n partly catalytically reacted in the contacting tray 21a so that the S03-containing gase~ from the contacting tray 21a are cooled from about 617C to about 540C The S03-containing gases are conductcd through duct 22, heat exchanger 23 and duct 24 to a co.ntacting tray 21b and enter the same at about 450C.
: The gases which have been catalytically rcacted further in contact-i.ng tray 21b leave the same through conduit 22a at a temperature of about 570C and are cooled to about 460C i.n a heat exchanger 23a and conducted to a contacting tray 21c through duct 24a.
About 89,930 standard m~/h of S03-containing gases at about 507C are co.nducted through duct 25 to an interstage heat exchanger 26 and are cooled therein to about 280C (at 26a) by a heat exchange with the gases which have been subjected to absorp-tion. The cooled gases are then cooled further to about 190C in a heat exchanger 27 and are then fed through duct 28 to a Venturi-tube interstage absorber 29. About 79,100 standard m3/h of gases from which almost all S03 has been removed are conducted through duct 30 and spray separator 31 and leave the interstage absorption system through duct 32 at about 140C.
The highly concentrated absorber acid which co.ntains H2S04 in a high conce.ntration of about 98.5-99.0% by weight is circulated through conduit 5a, cooler 6a, co.nduit 7a, pump 8a, conduit 9a, and nozzle lOa.
The gases are fed through duct 32 to the heat exchanger 26 and at about 440C are fed through duct 33 to a contacting tray 21d and leave the same at abou-t 482C through duct 34. The gases ~hich have been catalytically reacted further are cooled to about 420C in a heat exchanger 35 and are fed through duct 36 to a contacting tray 21e. About 78,590 standard m3/h of completely catalytically reacted gases at about 422C leave the catalytic reaction vessel 21 through duct 37 and are cooled to about 180C
in a heat exchanger 40 and are fed through conduit 41 to a Venturi _ g _ 1~99~84 tube final absorber 42. About 77,485 standard m3/h contact process exhaust gas are withdrawn from the final absorber 42 through duct 43, spray separator 44, and duct 45.
~ he absorber acid which contains H2S04 in a high concentration ol about 98.5-99.0~ by weight is circulated through co.nduit 5b, cooler 6b, co.nduit 7b, pump 8b, conduit 9b, conduit 9z, and.nozzle lOb. The circulated acids are adjusted to -the optinum acid concentration which is required in that acid is exchanged through conduits 9e, 9k, 9d, and 9i and additional water required for dilutio.n is added through conduits 9f and 9h. Product which contains about 96~ by volume H2S04 is discharged through co.nduit 9g.
Contact process exhaust gases which are virtually free from water ~apor and at about 110C are co.nducted through duct 45, heat exchanger 40, co.nduit 46, and heat exchanger 35 and are thus preheated to about 420C and through co.nduit 46a are fed to a system (not sho~n) for increasing the concentration of dilute acid with utilizatio.n of the heat conte.nt of the gases.
EXAMP.~E 2 The contact process system shown i.ln ~ig. 2 differs from ~xample 1, ~ig. 1, as follows:
a) Gas duct lla is co.nnected to the pressure side of blower 12a rather than to the suction side of blower 12 so that the blower 12 must handle o.nly 54pl70 standard m3/h dried air rather than 81,350 standard m3/h mixed gases and the blower 12a must handle 40,830 standard m3/h highly co.ncentrated S02 gas rather than '.
13,650 standard m3/h highly concentrated gas;
b) Only the heat exchanger 40 is used to preheat the contact process exhaust gases. ~hese are preheated in the heat exchanger 40 from about 110C to about 340C and are then fed .
through duct 46 to a stage (not show.n) for increasing the co.ncentra-tio.n of dilute acid.
1()99~84 c) The heat exchanger 35 is used to preheat atmospheric air~ Air at the rate of about 62,285 standard m3/h which is required to entrain water vapor for a stage (not shown) for increas-ing the concentration of dilute acid is fed through duct 47 at about 30C to the he~t exchanger 35 and is preheated therein to about 115C and is the.n fed through conduit 46a to a stage (not shown) for increasing the co.ncentration of dilute acid.
EXAMP_E 3 The contact process system shown i.n Fig. 3 is designed for a production of about 1000 metric tons of S03 per day from gases which contain about 17.0% by volume of S02, about 1.50 by volume 2' balance N2~C02, and have been produced by the decomposition of sulfuric acid and/or sulfates.
About 67,430 standard m3/h dried gas which contains about 17.0~ by volume S02 and is at about 65C are sucked by a ~`
blower 12a through duct lle. About 63,570 standard m3th dried air at about 65C are sucked by a blower 12 through duct llc.
53,900 standard m3/h of gas which contains about 17.0% by volume S2 are fed through duct lla and admixed to the total air stream.
~he resulti.ng gas mixture contains about 7.8% by volume S02 and about 1200~o by volume 2 and is fed at a rate of 117,470 standard m3/h through ducts 13, 14, 15, 16, 17, 18, and 20 to a first contacti.ng tray 21a of a càtalytic reaction vessel 21~ ~hese gases are preheated from about 90C to about 260C i.n a heat exchanger 40 and from about 260C to about 440C in two heat exchangers 23 and 35 by a heat exchange with S03-containing gases. 13,530 standard m3/h gas which contai.ns about 17.0% by volume S02 and is at about 90C are conducted through duct 13a and admixed to the S03_containing gases which have been partly catalytically reacted in contacting tray 21a and which are thus cooled from 610C to about 550C. ~he S03-containing gases are onducted through a duct 22 and the heat exchanger 23 and are 1099~84 then fed at a temperature of about 450C to a contacting tray 21b.
~ bout 126,240 standard m3/h S03-containing gases at about 527C are fed through conduit 25 -to an interstage heat exchanger 26 and are cooled therein to abou.t 277C (at 26a) by a heat exchange with the gases that have been subjected to absorptio.n. The cooled gases are cooled further to about 185C
in a heat exchanger 27 and are then fed through duct 28 to a Venturi tube interstage absorber 29, ~lhich is fed through conduit 9g with acid that is sprayed through nozzle lOa.
About 116,570 standard m3/h of gases from which almost all S03 has bee.n removed are conducted through duct 30 and spray separator 31 and leave the interstage absorption system through duct 32 at about 140C and are then fed to heat exchanger 26 and thereafter at about 430C through duct 33 to a contacting tray 21d. Gases at about 470C leave the contacting ~ray 21d through duct 34 and are cooled to about 420C in the heat exchanger 35 and then fed through duct 36 to a co.ntacting tray 21e. About 115,820 standard m3/h of gases which have been completely catalytically reacted and are at about 422C leave the catalytic reaction vessel 21 through duct 37 and are cooled to about 255C ; .
in heat exchanger 40 and then fed through duct 37a to a heat exchanger 40a, in which the gases are cooled to about 180C before they are fed through duct il to the final absorber.
About 50,000 standard m3/h atmospheric air at about 30C are fed through duct 45 to the heat exchanger 40a and are pre-heated therein to about 210C and are then fed through duct 46 to a stage (not shown) for i.ncreasi.ng the co.ncentration of dilute acid.
About 100,000 standard m3/h of atmospheric air at about 30C are fed through duct 47 to the heat exchanger 27 and are preheated therein to about 160C and are then fed through duct 46a to a stage (not shown) for i.ncreasing the conce.ntration of dilute acid.
The advantages of the inventio.n reside mainly in that :
99~84 surplus heat from the contact process system, inclusive of heat which becomes available at relatively low temperature, can be economically used to increase the co.ncentration of dilute sulfuric acids so that the consumption of expensive primary energy or the use of heat at high temperature can be avoided or reduced.
Claims (9)
1. A process of producing sulfuric acid which comprises catalytically reacting SO2 to form SO3 in gases which contain more than 10% by volume SO2 and which have been cooled, purified and dried before being fed to the catalytic reaction system, heating purified SO2-containing gases to the operating temperature of the first contacting tray by a heat exchange with SO3-containing hot gases which flow between contacting trays and which are cooled by said heat exchange to the operating temperature of the next following contacting tray, subjecting the SO3 which has been formed in a plu-rality of contacting trays of a first catalytic reaction stage to interstage absorption in sulfuric acid at elevated temper-ature, subjecting the SO3-containing gases which leave the first catalytic reaction stage to cooling in two stages before the gases are subjected to interstage absorption, reheating in the first cooling stage the gases which leave the inter-stage absorption system to the operating temperature of the next following contacting tray, subjecting the gases which have been completely catalytically reacted in the second catalytic reaction stage to cooling in a final heat ex-changer whereby heat is recovered which is not required in the catalytic reaction system, and absorbing in a final absorber the SO3 which has been produced in the second catalytic reaction stage, characterized by the combination of the following step:
(a) combining the production of sulfuric acid with an increase of the concentration of dilute sulfuric acid;
(b) adding oxygen-containing gases to a partial stream of SO2-containing gases at such a rate that the gas mixture can be reacted at least in a first contacting tray until the reaction has pro-ceeded to an equilibrium below or at the highest temperature which is permissible for the catalyst;
(c) heating said resulting gas mixture to the operating temperature of said first contacting tray by subjec-ting it to heat exchange with hot sulphur trioxide-containing gases flowing between contacting trays;
(d) adding the remaining SO2-containing gas to the sul-phur trioxide-containing gas from at least the first contacting tray of the first catalytic reaction stage;
(e) controlling the rate at which the partial stream of SO2-containing gases is fed to the first contacting tray so that SO3 is produced in step (b) at such a rate that the ratio of SO2:SO3 in the mixture prod-uced in step (d) is such that the reaction in the fol-lowing contacting trays can proceed to an equilibrium below or at the highest temperature which is permissi-ble for the catalyst;
(f) removing SO3 from the catalytically reacted gases by interstage and final absorption at operating temper-atures of 100-200°C;
(g) conducting the catalytic reaction in the second cata-lytic reaction stage in at least two contacting trays and cooling the gases between the contacting trays;
(h) expelling water from the dilute sulfuric acids by di-rectly contacting the acids with hot gases consisting of the contact process exhaust gases which have been subjected to final absorption or of inert gases having a low water content, or a mixture thereof;
(i) heating the expelling gases with at least part of the heat which becomes available in the final heat ex-changer, which follows the second catalytic reaction stage;
(j) heating the expelling gases with at least part of the heat which becomes available during the cooling of the catalytically reacted gases in step (g) or with at least part of the heat which becomes available in the second cooling stage which follows the first ca-talytic reaction stage and precedes the interstage absorption, or both and (k) using the heat energy derived from the acids which are circulated through at least one of the devices in the group comprising the dryer, the interstage absorber and the final absorber so as to increase the concentration of or to preheat the dilute sul-furic acid, or both.
(a) combining the production of sulfuric acid with an increase of the concentration of dilute sulfuric acid;
(b) adding oxygen-containing gases to a partial stream of SO2-containing gases at such a rate that the gas mixture can be reacted at least in a first contacting tray until the reaction has pro-ceeded to an equilibrium below or at the highest temperature which is permissible for the catalyst;
(c) heating said resulting gas mixture to the operating temperature of said first contacting tray by subjec-ting it to heat exchange with hot sulphur trioxide-containing gases flowing between contacting trays;
(d) adding the remaining SO2-containing gas to the sul-phur trioxide-containing gas from at least the first contacting tray of the first catalytic reaction stage;
(e) controlling the rate at which the partial stream of SO2-containing gases is fed to the first contacting tray so that SO3 is produced in step (b) at such a rate that the ratio of SO2:SO3 in the mixture prod-uced in step (d) is such that the reaction in the fol-lowing contacting trays can proceed to an equilibrium below or at the highest temperature which is permissi-ble for the catalyst;
(f) removing SO3 from the catalytically reacted gases by interstage and final absorption at operating temper-atures of 100-200°C;
(g) conducting the catalytic reaction in the second cata-lytic reaction stage in at least two contacting trays and cooling the gases between the contacting trays;
(h) expelling water from the dilute sulfuric acids by di-rectly contacting the acids with hot gases consisting of the contact process exhaust gases which have been subjected to final absorption or of inert gases having a low water content, or a mixture thereof;
(i) heating the expelling gases with at least part of the heat which becomes available in the final heat ex-changer, which follows the second catalytic reaction stage;
(j) heating the expelling gases with at least part of the heat which becomes available during the cooling of the catalytically reacted gases in step (g) or with at least part of the heat which becomes available in the second cooling stage which follows the first ca-talytic reaction stage and precedes the interstage absorption, or both and (k) using the heat energy derived from the acids which are circulated through at least one of the devices in the group comprising the dryer, the interstage absorber and the final absorber so as to increase the concentration of or to preheat the dilute sul-furic acid, or both.
2. A process according to claim 1, charac-terized in that the remaining SO2-containing gas is admixed in step (d) at such a rate that the resulting mixture is at a gas temperature which corresponds to the operating tem-perature of the next following contacting tray.
3. A process according to claim 1 or 2, characterized in that the oxygen-containing gases are sep-arately dried with sulfuric acid before being fed to the catalytic reaction vessel.
4. A process according to claim 1, characterized in that the oxygen-containing gases or the SO2-containing gases, or both are dried at elevated temperatures and are at a temperature of 60-80°C, when leaving the dryer.
5. A process according to claim 1, charac-terized in that the mixture of the partial stream of SO2-con-taining gases and the oxygen-containing gases added thereto in step b) is handled by a blower.
6. A process according to claim 1, charac-terized in that the oxygen-containing gases are handled by a blower before they are added in step b) to the partial stream of SO2-containing gases.
7. A process according to claim 1, charac-terized in that the drying or interstage or both, is effected at least in part as a cocurrent operation in Venturi-tube absorbers.
8. A process according to claim 4, wherein the gases are at temperatures of 65 to 70°C when leaving the dryer.
9. A process according to claim 1, charac-terized in that the operating temperatures in step f) are ranging from 110° to 160°C.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE2529709A DE2529709C3 (en) | 1975-07-03 | 1975-07-03 | Process for the production of sulfuric acid |
| DEP.2529709.0 | 1975-07-03 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1099484A true CA1099484A (en) | 1981-04-21 |
Family
ID=5950590
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA256,082A Expired CA1099484A (en) | 1975-07-03 | 1976-06-30 | Process of producing sulfuric acid |
Country Status (15)
| Country | Link |
|---|---|
| JP (1) | JPS5235793A (en) |
| BE (1) | BE843772A (en) |
| BR (1) | BR7604336A (en) |
| CA (1) | CA1099484A (en) |
| DE (1) | DE2529709C3 (en) |
| ES (1) | ES448720A1 (en) |
| FI (1) | FI761918A (en) |
| FR (1) | FR2316187A1 (en) |
| GB (1) | GB1553307A (en) |
| IN (1) | IN143873B (en) |
| IT (1) | IT1079128B (en) |
| NL (1) | NL7604961A (en) |
| NO (1) | NO761603L (en) |
| SE (1) | SE417700B (en) |
| ZA (1) | ZA762985B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110538543A (en) * | 2019-08-30 | 2019-12-06 | 楚雄滇中有色金属有限责任公司 | Method for stably reaching standard of tail gas in initial stage of acid making and coproduction by smelting flue gas |
| WO2023225742A1 (en) * | 2022-05-27 | 2023-11-30 | Chemetics Inc. | Tail gas treatment system and method for a sulfuric acid production plant |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2429748A1 (en) * | 1978-06-28 | 1980-01-25 | B St P Realizac | Catalytic oxidn. of sulphur di:oxide to tri:oxide - in sulphuric acid mfr., by double conversion using wall heat exchange to increase heat exchange intensity |
| DE2847602C2 (en) * | 1978-11-02 | 1986-10-23 | Biuro Studiów, Projektów i Realizacji Inwestycji Przemysłu Nieorganicznego Biprokwas, Gleiwitz/Gliwice | Process for the production of sulfuric acid |
| DE2945021A1 (en) * | 1979-11-08 | 1981-05-21 | Metallgesellschaft Ag, 6000 Frankfurt | METHOD FOR PRODUCING CONCENTRATED SULFURIC ACID |
| CA1146722A (en) * | 1981-04-10 | 1983-05-24 | Gordon M. Cameron | Energy recovery method and system for combined sulphuric and phosphoric acid manufacturing plant |
| DE3232446A1 (en) * | 1982-08-12 | 1984-02-16 | Metallgesellschaft Ag, 6000 Frankfurt | METHOD FOR PRODUCING SULFURIC ACID |
| DE3303287A1 (en) * | 1983-02-01 | 1984-08-02 | Bayer Ag, 5090 Leverkusen | METHOD FOR PRODUCING SULFURIC ACID |
| US4576813A (en) * | 1983-07-05 | 1986-03-18 | Monsanto Company | Heat recovery from concentrated sulfuric acid |
| US4670242A (en) * | 1984-11-09 | 1987-06-02 | Monsanto Company | Heat recovery from concentrated sulfuric acid |
| JPS60145200A (en) * | 1984-01-06 | 1985-07-31 | 松下電器産業株式会社 | Ironing stand |
| JPS62166000U (en) * | 1986-04-10 | 1987-10-21 | ||
| DE19800800C2 (en) * | 1998-01-13 | 2001-05-23 | Metallgesellschaft Ag | Process for the production of sulfuric acid |
| DE102007058144A1 (en) * | 2007-11-30 | 2009-06-04 | Outotec Oyj | Producing sulfuric acid from a gas containing sulfur dioxide comprises catalytically oxidizing the sulfur dioxide in a converter to obtain sulfur trioxide and absorbing the sulfur trioxide in concentrated sulfuric acid in absorber |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL136387C (en) * | 1964-11-06 | |||
| DE1567716B2 (en) * | 1966-12-03 | 1977-02-17 | Metallgesellschaft Ag, 6000 Frankfurt | METHOD OF CATALYTIC REALIZATION OF SO LOW 2 AND SO LOW 3 AND SULFUR ACID PRODUCTION |
| BE788625A (en) * | 1971-09-11 | 1973-01-02 | Metallgesellschaft Ag | PROCESS FOR THE REMOVAL OF SULFURIC ANHYDRIDE AND SULFURIC ACID MIST CONTAINED IN GASES |
-
1975
- 1975-07-03 DE DE2529709A patent/DE2529709C3/en not_active Expired
-
1976
- 1976-05-10 NO NO761603A patent/NO761603L/no unknown
- 1976-05-10 NL NL7604961A patent/NL7604961A/en not_active Application Discontinuation
- 1976-05-19 ZA ZA762985A patent/ZA762985B/en unknown
- 1976-06-10 ES ES448720A patent/ES448720A1/en not_active Expired
- 1976-06-14 GB GB24600/76A patent/GB1553307A/en not_active Expired
- 1976-06-17 IN IN1063/CAL/76A patent/IN143873B/en unknown
- 1976-06-25 FR FR7619404A patent/FR2316187A1/en active Granted
- 1976-06-25 IT IT24701/76A patent/IT1079128B/en active
- 1976-06-30 CA CA256,082A patent/CA1099484A/en not_active Expired
- 1976-07-01 FI FI761918A patent/FI761918A/fi not_active Application Discontinuation
- 1976-07-02 SE SE7607631A patent/SE417700B/en unknown
- 1976-07-02 BE BE6045582A patent/BE843772A/en not_active IP Right Cessation
- 1976-07-02 JP JP51079402A patent/JPS5235793A/en active Pending
- 1976-07-02 BR BR7604336A patent/BR7604336A/en unknown
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110538543A (en) * | 2019-08-30 | 2019-12-06 | 楚雄滇中有色金属有限责任公司 | Method for stably reaching standard of tail gas in initial stage of acid making and coproduction by smelting flue gas |
| CN110538543B (en) * | 2019-08-30 | 2021-07-13 | 楚雄滇中有色金属有限责任公司 | Method for stably reaching standard of tail gas in initial stage of acid making and coproduction by smelting flue gas |
| WO2023225742A1 (en) * | 2022-05-27 | 2023-11-30 | Chemetics Inc. | Tail gas treatment system and method for a sulfuric acid production plant |
Also Published As
| Publication number | Publication date |
|---|---|
| FR2316187A1 (en) | 1977-01-28 |
| FR2316187B1 (en) | 1981-11-06 |
| DE2529709A1 (en) | 1977-01-20 |
| IN143873B (en) | 1978-02-18 |
| DE2529709B2 (en) | 1980-06-12 |
| JPS5235793A (en) | 1977-03-18 |
| NO761603L (en) | 1977-01-04 |
| SE7607631L (en) | 1977-01-04 |
| ES448720A1 (en) | 1977-07-01 |
| SE417700B (en) | 1981-04-06 |
| NL7604961A (en) | 1977-01-05 |
| FI761918A (en) | 1977-01-04 |
| BR7604336A (en) | 1977-07-26 |
| DE2529709C3 (en) | 1981-02-26 |
| GB1553307A (en) | 1979-09-26 |
| IT1079128B (en) | 1985-05-08 |
| ZA762985B (en) | 1977-04-27 |
| BE843772A (en) | 1977-01-03 |
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