CA1104791A - Method of preparing sulphur dioxide - Google Patents
Method of preparing sulphur dioxideInfo
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- CA1104791A CA1104791A CA288,474A CA288474A CA1104791A CA 1104791 A CA1104791 A CA 1104791A CA 288474 A CA288474 A CA 288474A CA 1104791 A CA1104791 A CA 1104791A
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- sulphur
- oxygen
- vapour
- bed
- fluidized bed
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Abstract
METHOD OF PREPARING SULPHUR DIOXIDE
ABSTRACT
The method of preparing sulphur dioxide consists in that sulphur is melted and evaporated by bubbling oxygen through molten sulphur, and the formed vapour is oxidized with oxygen in a fluidized bed of an inert material. The concentration of the end product is up to 100 per cent by volume. The proposed method ensures the productivity of the process up to 2000 - 3400 kg per square metre of the surface of evaporation per hour, the pressure being from 1 to 35atm..
ABSTRACT
The method of preparing sulphur dioxide consists in that sulphur is melted and evaporated by bubbling oxygen through molten sulphur, and the formed vapour is oxidized with oxygen in a fluidized bed of an inert material. The concentration of the end product is up to 100 per cent by volume. The proposed method ensures the productivity of the process up to 2000 - 3400 kg per square metre of the surface of evaporation per hour, the pressure being from 1 to 35atm..
Description
11~4791 This invention relates to the method of preparing sulphur dioxide used in the manu4acture o~ su~phuric acid and in the pulp-and-paper industry.
~ nown in the prior ar-t is -the method of preparin~ sul-phur dioxide o~ high concentration (to 90 per cent by ~oiume) by burning sulphu~ in a gaseous mixture consisting of o~e volume of oxygen and five volumes o- sulphur dioxide. ~he pro-cess is xealized in special furnaces at a temperature o4 1200C. The furnace construction i5 characterized by the presence o~ two nozzles for spraying sulphur, and heat exch~
angers ~or cooling return gas, the major part o~ which is delivered into the reactor to maintain t~e required tempera-ture conditions.
Disadvarltages of the known ~ethod are low intensity of the process owing to recycling of the return gas in the reac-tor, complexity o~ the process flow-sheet because of the necessi-t~ of fine p~lrification o~ sulphur and the presence of external heat-exchangers. It is alsc difficult to effect the process at elevated pressures du~ to high process tempe-ratu~es in the wor~ing zone o~ the fuxnace (1200C).
Known also in the prior art is another method o~ pxepar-ing sulphur dioxide of high concentration by si~ultaneously meltin~ lump sulphur, evaporating it, and oxidizing ~iith ox~en blo~n throu~h a fluidized bed.
~ he disadvant~ge of this method is that lt is impposibl~
to realize the pxocess on an industrial scale because of a ., ,. ~: ',` ' :
" '' ` '' ':
79~ j sharp rise in tne process temperature i~ oxygen is used in '~
the blowing process instead of air. ~he tempera-ture rises to above 2500C, and the problem of heat withdrawal is not solved.
As the bed o~ an inert material is fluidized, sulphur can get into its upper layers and its vapour can burn in the 7 zone above the bed.
Another disadvantage of this method is also impossibilit~
of carrying out the process under excess pressure since the specific evolution o~ heat is intensified in proportion wit~
growing pressure.
Enown widely in the prior art is also a method of pre-paring sulphur dioxide ~rom sulphur by bubbling primary air, in the quantity of 0.5 - 1.0 per cent of the total volume of the air, through a bed of molten sulphur with subsequent oxi-dation of sulphur vapour in the combustion chamoer, where the secondary air is delivered tange~tially, in a cyclone, to ensure complete combustion of sulphur vapour.
Crushed lu~p sulphur is delivered by a screw feeder into the lou~er part o~ the furnace, into the bubbling zone, where it is melted by the heat of liquid sulphur. ~o accele-rate this process, the primary air is delivered into the bed. ;
~he bubbling i~te~si~ies agitatio~ of the melt in the verti-cal plane of the bed, and the melt surface is thus co~stantly renewed. q'he tel~perature of the bubbled layer is 300 -380C, and the boiling point (444C) i3 attai~ed at atmospheric ~ 3 --.,. .. , ,.. ,, ,, " .
-- -- ~ , - , ;, . -.. ... .. .: , - , ", ,,~ , ~
.. ...... . ..
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pressure only at the interface. T~e main quantity o~ vapour is generated at the sur~ace o~ the bed by this method.
~ he method suitable ~or vJork with impure sulphur, with periodically removing the s~udge from the lower part of the fur~ace. ~he heat stress of t~e furnace is higher than with sprayer-type furnaces, and is about 1.7 X106 kcal/cu.m x hr.
The obtained sulphur dioxid\e has the concentration of 12 - j 18 per cent by volume.
The disadvantage of this method is the 10W concentration of the obtained sulphur dioxide (not above 18 per cent by volume) The specific obaect of the invention is to prepare sul-phur dioxide having high concentration (to 100 per cent by volume) within a wide range of pressures, ~rom 1 to 35 atm.
~nother object of the invention is to intensily the process of preparing sulphur dioxide 1.5 - 3.0 times. S
Still another object o~ the invention is to provide a method that would rule out the action o~ high temperatures on the furnace structures under elevated pressures.
The essence of the invention consists in that in the met~od for preparing sulphur dioxide from sulphur by melting the latter, evaporating it in a bubbled bed, and-oxidizing the obtairled sulp~ur vapour into the end product, according to the invention, sulphur is evaporated by bubbling oxygen through molten sulphur, while the formed sulphur vapour is oxidized ~ith oxygen in a ~luidized bed of an inert material.
"
-, - ~ ,; . . ~ . . , -, ~ . ., :.. .. .. .
;. ~
. . ~ ... .
~ 4791 T~s proposed method makes it possible to burn sulphur f directly in a stream of oxygen, which intensi~ies the proce3s of preparing sulphur dioxide.
It is recommended that sulphur be evaporated by bubbling oxygen through molten sulp~ur at the temperature o~ its-boil-ing point, which ensures maximum evaporation o~ sulp~ur.
Sulphur can be evaporated and the vapour oxidized under a pressure o~ from 1 to 35 atmospheres.
It is recommended that quartz sand, silica gel or alu-mino~ilicate be used as the inert material.
~ he ~urther des~ription o~ the invention will be illu strated by a process flow-sheet given in the appended draw-ing. Crushed sulphur is melted in chamber 1, heated by steam through coils 2, or by any other suitable method. Molten sulphur is then purified by pa~sing throu~h a ~ilter chamber 3. ~he molten and purified sulphur, at a temperature o~ 140 -150C, is delivered by a pump 4 into a bubbling chamber 5 o~
the furnace, where oxygen is sparged through the molten bed 7 of sulphur by a bubbler 6.
The oxygen delivery rate is calculated ~ith respect to the heat and material balance, and depends on the process parameters. Unlike in the known bubbling met~od, the oxida-tion and evaporation processes in the proposed method occur inside a ~as bubble. Because o~ the chain character o~ the burning process, sulphur vapour burns in oxygen in tenth ~rac~ions o~ a second. ~he temperature inside a bubble rises ; -,, :,..:
; .: . . . . .
suddenly and attains the point close to the theoretical te~-perature of adiabatic burning of sulphur in o~ygen (about 3000 - 3500C)~
As the gas bubble rises through the molten sulphur, it exchanges its heat with the m~lt 7, the heat-exchange process being completed at the depth of 1 - 1.5 m ~rom the melt sur-~ace to the bubbler (experimental data). During the process, the gas bubbles do not come in direct contact with the ele-ments of the apparatus, and the walls of the reaction chamber are not heated a~ove the temperature of the melt. ~he c~mposi-tion of the vapour-gas mixture, as it issues ~rom the bubbli chamber 5, is determIned by the process parameters, such as pressure, temperature, and heat loss. In the proposed method, the heat of the reaction in the bubbling zone of the furnace is con~umed to evaporate sulphur, and to heat the melt to the working temperature.
~ he composition of the mixture can be regulated b~ with-drawing part of heat using special heat-exchangers 8 located in the bubbling bed.
Sulphur vapour and par~ of sulphur diexide are passed through a gas distributing grating 9 into the fluidized bed o~ inert material 10. ~he secondary oxygen is delivered , . . .
through the bubbler 11 in a small excess (1 - 1.5 per cent with resl~ect to stoichiometric) i~ 100 per cent S02 is requi-red. By va~ying the amount of excess oxygen, the required concentrations of S02 in the gas are obtained. ~Ieat-exchang-. .
.... ..
,.. . . :.:
~, - .. , ~ . .. .- -. : . . .
~1~4~91 ers 12 serve to withdraw heat ~rom the ~luidized bed zone. -~he hig~ values of the heat transfer coefficien~ in the fluidized bed make it possible to rnaint-ain the ternperature in the bed at 600 - 700C. Common lining and construction materials can thus be u~ed in the manufacture of the appara-tus.
~ he holding capacity of the apparatus for preparing sulphur dioxide under pressure, decreases with the growing pressure. ~he specific capacity o~ the furnace for the manu-facture of sulphur dioxide by the proposed method, is about j~
~ nown in the prior ar-t is -the method of preparin~ sul-phur dioxide o~ high concentration (to 90 per cent by ~oiume) by burning sulphu~ in a gaseous mixture consisting of o~e volume of oxygen and five volumes o- sulphur dioxide. ~he pro-cess is xealized in special furnaces at a temperature o4 1200C. The furnace construction i5 characterized by the presence o~ two nozzles for spraying sulphur, and heat exch~
angers ~or cooling return gas, the major part o~ which is delivered into the reactor to maintain t~e required tempera-ture conditions.
Disadvarltages of the known ~ethod are low intensity of the process owing to recycling of the return gas in the reac-tor, complexity o~ the process flow-sheet because of the necessi-t~ of fine p~lrification o~ sulphur and the presence of external heat-exchangers. It is alsc difficult to effect the process at elevated pressures du~ to high process tempe-ratu~es in the wor~ing zone o~ the fuxnace (1200C).
Known also in the prior art is another method o~ pxepar-ing sulphur dioxide of high concentration by si~ultaneously meltin~ lump sulphur, evaporating it, and oxidizing ~iith ox~en blo~n throu~h a fluidized bed.
~ he disadvant~ge of this method is that lt is impposibl~
to realize the pxocess on an industrial scale because of a ., ,. ~: ',` ' :
" '' ` '' ':
79~ j sharp rise in tne process temperature i~ oxygen is used in '~
the blowing process instead of air. ~he tempera-ture rises to above 2500C, and the problem of heat withdrawal is not solved.
As the bed o~ an inert material is fluidized, sulphur can get into its upper layers and its vapour can burn in the 7 zone above the bed.
Another disadvantage of this method is also impossibilit~
of carrying out the process under excess pressure since the specific evolution o~ heat is intensified in proportion wit~
growing pressure.
Enown widely in the prior art is also a method of pre-paring sulphur dioxide ~rom sulphur by bubbling primary air, in the quantity of 0.5 - 1.0 per cent of the total volume of the air, through a bed of molten sulphur with subsequent oxi-dation of sulphur vapour in the combustion chamoer, where the secondary air is delivered tange~tially, in a cyclone, to ensure complete combustion of sulphur vapour.
Crushed lu~p sulphur is delivered by a screw feeder into the lou~er part o~ the furnace, into the bubbling zone, where it is melted by the heat of liquid sulphur. ~o accele-rate this process, the primary air is delivered into the bed. ;
~he bubbling i~te~si~ies agitatio~ of the melt in the verti-cal plane of the bed, and the melt surface is thus co~stantly renewed. q'he tel~perature of the bubbled layer is 300 -380C, and the boiling point (444C) i3 attai~ed at atmospheric ~ 3 --.,. .. , ,.. ,, ,, " .
-- -- ~ , - , ;, . -.. ... .. .: , - , ", ,,~ , ~
.. ...... . ..
~1~4~79~ ~
' ~'.
pressure only at the interface. T~e main quantity o~ vapour is generated at the sur~ace o~ the bed by this method.
~ he method suitable ~or vJork with impure sulphur, with periodically removing the s~udge from the lower part of the fur~ace. ~he heat stress of t~e furnace is higher than with sprayer-type furnaces, and is about 1.7 X106 kcal/cu.m x hr.
The obtained sulphur dioxid\e has the concentration of 12 - j 18 per cent by volume.
The disadvantage of this method is the 10W concentration of the obtained sulphur dioxide (not above 18 per cent by volume) The specific obaect of the invention is to prepare sul-phur dioxide having high concentration (to 100 per cent by volume) within a wide range of pressures, ~rom 1 to 35 atm.
~nother object of the invention is to intensily the process of preparing sulphur dioxide 1.5 - 3.0 times. S
Still another object o~ the invention is to provide a method that would rule out the action o~ high temperatures on the furnace structures under elevated pressures.
The essence of the invention consists in that in the met~od for preparing sulphur dioxide from sulphur by melting the latter, evaporating it in a bubbled bed, and-oxidizing the obtairled sulp~ur vapour into the end product, according to the invention, sulphur is evaporated by bubbling oxygen through molten sulphur, while the formed sulphur vapour is oxidized ~ith oxygen in a ~luidized bed of an inert material.
"
-, - ~ ,; . . ~ . . , -, ~ . ., :.. .. .. .
;. ~
. . ~ ... .
~ 4791 T~s proposed method makes it possible to burn sulphur f directly in a stream of oxygen, which intensi~ies the proce3s of preparing sulphur dioxide.
It is recommended that sulphur be evaporated by bubbling oxygen through molten sulp~ur at the temperature o~ its-boil-ing point, which ensures maximum evaporation o~ sulp~ur.
Sulphur can be evaporated and the vapour oxidized under a pressure o~ from 1 to 35 atmospheres.
It is recommended that quartz sand, silica gel or alu-mino~ilicate be used as the inert material.
~ he ~urther des~ription o~ the invention will be illu strated by a process flow-sheet given in the appended draw-ing. Crushed sulphur is melted in chamber 1, heated by steam through coils 2, or by any other suitable method. Molten sulphur is then purified by pa~sing throu~h a ~ilter chamber 3. ~he molten and purified sulphur, at a temperature o~ 140 -150C, is delivered by a pump 4 into a bubbling chamber 5 o~
the furnace, where oxygen is sparged through the molten bed 7 of sulphur by a bubbler 6.
The oxygen delivery rate is calculated ~ith respect to the heat and material balance, and depends on the process parameters. Unlike in the known bubbling met~od, the oxida-tion and evaporation processes in the proposed method occur inside a ~as bubble. Because o~ the chain character o~ the burning process, sulphur vapour burns in oxygen in tenth ~rac~ions o~ a second. ~he temperature inside a bubble rises ; -,, :,..:
; .: . . . . .
suddenly and attains the point close to the theoretical te~-perature of adiabatic burning of sulphur in o~ygen (about 3000 - 3500C)~
As the gas bubble rises through the molten sulphur, it exchanges its heat with the m~lt 7, the heat-exchange process being completed at the depth of 1 - 1.5 m ~rom the melt sur-~ace to the bubbler (experimental data). During the process, the gas bubbles do not come in direct contact with the ele-ments of the apparatus, and the walls of the reaction chamber are not heated a~ove the temperature of the melt. ~he c~mposi-tion of the vapour-gas mixture, as it issues ~rom the bubbli chamber 5, is determIned by the process parameters, such as pressure, temperature, and heat loss. In the proposed method, the heat of the reaction in the bubbling zone of the furnace is con~umed to evaporate sulphur, and to heat the melt to the working temperature.
~ he composition of the mixture can be regulated b~ with-drawing part of heat using special heat-exchangers 8 located in the bubbling bed.
Sulphur vapour and par~ of sulphur diexide are passed through a gas distributing grating 9 into the fluidized bed o~ inert material 10. ~he secondary oxygen is delivered , . . .
through the bubbler 11 in a small excess (1 - 1.5 per cent with resl~ect to stoichiometric) i~ 100 per cent S02 is requi-red. By va~ying the amount of excess oxygen, the required concentrations of S02 in the gas are obtained. ~Ieat-exchang-. .
.... ..
,.. . . :.:
~, - .. , ~ . .. .- -. : . . .
~1~4~91 ers 12 serve to withdraw heat ~rom the ~luidized bed zone. -~he hig~ values of the heat transfer coefficien~ in the fluidized bed make it possible to rnaint-ain the ternperature in the bed at 600 - 700C. Common lining and construction materials can thus be u~ed in the manufacture of the appara-tus.
~ he holding capacity of the apparatus for preparing sulphur dioxide under pressure, decreases with the growing pressure. ~he specific capacity o~ the furnace for the manu-facture of sulphur dioxide by the proposed method, is about j~
2 - 3 times higher than of the apparatus used in the known method~ I
Realization of the proposed method o~ preparing sulphur ;
dioxide under pressure, increases the pro~uctivity to 2000 k~
per square metre of the bed surface per hour, the pressure being 10 - 35 atm, and the intensity being 3000 - 3500 kg/sq.m x hr undsr a pressure of 1 - 10 atm.
The proposed method has the following advantages:
1. The concentration of S02 in the obtained gas increa-ses to 100 per cent.
2. ~he concentration o~ oxygen in the blowin~ gas can be as high as 100 per cent by vol.
Realization of the proposed method o~ preparing sulphur ;
dioxide under pressure, increases the pro~uctivity to 2000 k~
per square metre of the bed surface per hour, the pressure being 10 - 35 atm, and the intensity being 3000 - 3500 kg/sq.m x hr undsr a pressure of 1 - 10 atm.
The proposed method has the following advantages:
1. The concentration of S02 in the obtained gas increa-ses to 100 per cent.
2. ~he concentration o~ oxygen in the blowin~ gas can be as high as 100 per cent by vol.
3. Bubbling of oxygen t~rough molten sulphur at a te~-perature of its boiling point, or at lower temperaturs, mar-kedly increases the surface of evaporation to intensify the pro~ess 1.5 - 3 times as compared with the known methods.
- . . .
. : : ., , ~.......... , 11Ç~47~1 ~
- . . .
. : : ., , ~.......... , 11Ç~47~1 ~
4. The temperature of the medium at the bubbling stage does not exceed 700 - 800C, which makes it possible to use com~on (non-refractory) construction materials.
5. Burning o~ sulphur in a fluidized bed of an inert material makes it psssible to remove the heat, liberated during o~idatio~ ~ sulphur by oxygen, directly from the reaction zone.
6. Oxidation of sulphur in a ~luidized bed of an inert material in the form of vapour, intense mixing of the v~pour with oxygen, make~ it possible to complete the process in the bed~ the temperature in the zone above the bed not exceeding the temperature of the bed.
7, ~he intensity of sulphur burning in the form of va-pour in a fluidized bed o~ an inert material incxeases 2-3 times as compared with the kno~m methods.
8. ~he proposed method makes it possible to obtain sul- i phur dioxide gas ha~ing the concentration of 100 per cen~ !
out of sulphur and oxygen under a pressure of up to 35 atm.
~ or a better understandin~ of the invention, the follow-ing exa~ples of its practical embodiment are given by way of illustration.
~ :amPle 1 Crushed sulphur containing to 5 per cent by weight of admixtures is delivered into a melting zone by a screw feeder at a rate of 7740 kg/hr. ~ sulphur melts, it is purified, , . .
:. . . : .
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.. . . , ,,, . , ,. . ~ : ~ . . . , : . .
.: -. . ~ . . -:. . . . .. . . . ..
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. . . ... .
... .. . ...
and pumped at a temperature of 140 - 150C into t~e bubbling chamber of the ~urnace. The cross section area of the bubbl-ing chamber is about 3 s~.m, and the diameter is 2 metres.
The height of -the sulphur melt is maintained at 1 metre, (in !
the stationary conditions). Th`e bubbling chamber is a separa-te apparatus, 3.5 m high. ~he height of the separation space above the melt is 0.8 m, and of the settling zone 1.2 m. ~he consumption rate of puri~ied sulphur is 7~70 kg/hr. ~echnical~
oxygen, containlng to 2 per cent by volume of inert gas, is used in the manufacture o~ sulphur dioxide. The process is effected u~der a pressure of 10 atm and at a te.~perature of the melt equal to the boili~g point of sulphur at a given pressure (646.1C), This temperature is maintained in the bubbling chamber by the heat liberated in the reaction of oxidation of part of sulphur with ox~gen as it is bubbled through the moltsn sulphur. The quantitg of oxygen at a tem-perature of 15 - 20C used for bubbling, under stabilized process conditions, i5 626.5 ~g/hr or 438.5 cu.m/hr (at STP).
~he quantity of inert gas that is bubbled together with oxy~-en is 28.9 k~/hr or 23.1 cu.m/hr (at STP). In the startin~
period, oxygen is heated to a temperature of 350 - 400C. As the process conditions get stabilized) the oxygen reacts in the melt with the sulphur vapour. ~he reaction inside the gas bubbles is complete. A vapour-gas mixture is formed as a re-sulk in the space above the molten sulphur, the mixture con sisting of sulphur vapour (6743 kg/hr or 4720 cu.m/hr~ at _ 9 _ :; - . - , , - , ~ :
~ 47 ~
S~P), sulphur dioxide (1253 kg/~r or 433.5 cu.m/hr, at STP), and inert gases (28.9 kg/hr or 23.1 cu.m/hr, at S~P). ~he output capacity of the bubbling chamber is 2500 kg/hrx sq.m.
The vapour-gas mixture is delivered through a gas-di-stributing grating into the chamber having the inner section diameter of 1.7 m and the ~eight of 3.4 m. The chamber is an apparatus where crushed quartz, having particles sizing 1.5 mm, is fluidized. The height of the fluidized bed is Ho = 1.2, which ensures complete combustion of sulphur vapor in an oxygen stream at a te~perature of 650C. Excess h~t of the reaction is withdra~n by heat-exchangers located di-- rectly in the fluidized bed. ~he temperature of the gas at the exit ~rom the apparatus has the same value.
The quantity of oxygen to be delivered into the fluidi-zed bed should be cal~ulated on the assemption t~at the obtained sulphur dioxide will be furt-her ~ to sulphur trioxide. ~or t~is reason, the total required quantity o~
oxygen (~or ~he suimary reaction) should be delivered into the ~urnace. Sincs part of oxygen is bubbled, the total re-quired quantity o~ oxygen is 11274 kg~hr, the excess factor being ~ = 0.02. Thus, 7453.4 cuOm/br (at S~P) o~ oxygen are delivered into the fluidized bed of an inert material thro-ugh a special device. ~e composition of the gas issued from the furnace is as follows: oxyge~ 32.9 per cent by volume, ~hich is equivalent to 3905 kg/hr or 2733 cu.m/~r (a~ STP), sulphur dioxide 62.1 per cent by volume, ~lhich is equivalerlt ~ .: . . - , .: - ' .
.. . . .:
-. , ,,. ~ .
- : ~:; . . .
: : .. . ... .. -:
. :, , . . ~, . . . ;
~4791 to 14,740 kg/hr or 5159 cu.m/hr (at S~P), and inert gases 5 per cent by volume, which is equivalent to 5~8 kg/hr or 415 cu.m/hr (at STP).
~ he product1on capacity of the furnace, with respect to !~
sulphur dioxide gas having -the specified composition, is 8300 cu.m/hr (at STP).
Exam~le 2 The process is carried out as described in ~xample 1, except that the pressure is 15 atm, and the temperature o~
the molten sulphur is maintained at 650C, which is below the melting point o~ sulphur at this pressure. ~i~uid sulphur (20412 kg/hr) is evaporated in the bubbling chamber by pass-ing 1113.9 kg/hr of technical oxygen containing 15 per cent by weight of inert gas admixtures. As a result, 19~47.5 kg/hr of sulphur vapour, ~130 kg/hr of sulphur dioxide, and 49 kg/br of nitrogen are obtained in the fluid bed having the height of 1.5 m and the inner diameter of the section o~ 3.3 m. ~he vapour-gas mixture is delivered into the fluidized bed of silica gel having particles o~ 1.5 mm. The height of ~he bed is Ho = 1..2 m, the diameter o~ the apparatus in the working zone is 1~6 m, and the gas velocity, in the ~orking condi-tions, is wp = 0,75 m/second. Oxygen is delivered into the fluidized bed in the ~uantity required for complete oxidation of sulphur vapour an~ sulphur dioxide to sulphur trioxide.
~aking into account t~e excess ratio factor ~ = 0,02, this ~uantity is 30166 k~/hr, or 21,116 cu.m/hr (at STP). Technical oxygen containing 5 p~r cent by volume of inert gas is used -, - 11 ~
...!
.
,. ., r ~ 47 9 B in the process. The temperature in the fluidized bed~ ~
maintained at 650C~ The ~ollowing products are obtained at the exit from the furnace:
sulphur dioxide 40,824 kg/~r, or 14,290 cu.~/hr (at STP), oxygen 10,819 kg/hr, or 7571 cu.m/hr (at STP), nitrogen 1437 kg/hr, or 1149 cu.m/hr (at STP).
~he composition o~ sulphurous acid gas i8:
S2 62.1 per cent by volume 2 32.g per cent bg volume N2 5 per cent by volume.
EscamPle ~
~ he process i~ realized as de3cribed in Example 1, except that the pressure is 25 atm, and the temperature o~
the molten sulphur in the bubbling chamber is 650C which is below the melting point of sulphur at this pressure.
EXcess heat is withdrawn by heat-exchangers that are located directly in the molten sulphur bed.
~ iquid sulphur having the temperature o~ 140 - 150~C is delivered i~to the bubbling chamber at a rate of 30234 kg/hr The height of the molten sulphur bed is 1.5 metre. ~he diame-ter of the apparatus is 3 metres, and its height is 16 me~res.
Technical oxygen is delivered into the apparatus under a pressure of 25 atm at a rate o~ 4559.9 kg/hr. ~he amount of delivered nitro~en is 20 kg/hr.
~ .
- - . .. - . . ........... . . . .
~ - - , - . .. , 11~4791 , The gaseous mixture discharged ~rom the bubbli~g cham-ber consists of sulphur dioxide (9120 kg/hr, which is 18.4 per cent by volume), sulphur vapour (25675 kg/hr, 81.2 per cent by ~olume) and inert gases (20 kg/hr, 0.42 per cent by volume). ~he mixture is delivePed into the ~luidized bed of silica gel (particle size, 1.5 mm). Technical oxygen contain-ing nitrogen (183.5 kg/hr) is delivered in~o the fluidized bed at a rate of 41,699 kg/hr. Sulphur vapour is completely oxidized in the ~.~uidized bed at a temperature of 650C, which is maintained at this point by withdrawing excess heat from the fluidized bed. The resultant gas consists o~ sulphur ~ioxide, 64.95 per cent by volume (60,468.6 kg/hr), oxygen 34,55 per cent by volume (16,024 kg/hr), and inert gases, 0.5 per cent by volume (203,5 kg/hr).
~ !
'~he process is carried out under a pressure of to 35 atm on a pilot plant. ~rom a melting chamber, having a capacitg of one cubic metre, sulphur is loaded periodically into the bubbling chamber in the quantity of 0.017 cu.m. The diameter of the chamber is ~.3 m, the bed height is 1 m. ~he total de-livery of oxygen is 60 cu.m/hr (~P). ~he quantity o~ ox~ygen - spent ~or bubbling is 20 per cent o~ the to~al quantity o~
oxygen. ~he production capacity of the svaporator is 130 kg/hr, t~e intensity o~ evaporation being 2000 kg per square meter of the sur~ace per hour. ~he inert material used in t~e fluidized bed is specially treated aluminosilicate catalyst . ,.
11~4791 having particles o~ 1.5 mm. The height of the bed is - 0.5 m. ~he temperature in the ~luidized bed is mai~tain-ed at 600 - 615C. ~he composition of the gas discharged ~rom the furnace is S02 48 - 50 per cent by volume 2 ~ - 40 per cent b~ volume S03 1.8 - 2 per ce~t by volume.
inert gases to make 100 per cent.
Example 5 ~ he process is carried out on a pilot plant under atmosp~eric pressure Pure sulphur is loaded periodically into a cylindrical apparatus, having the diameter of 0.008 m and a height o~ 1.2 m, and provided with an ex*ernal electric heater. ~he cover of the apparatus has t~o connections, for a bubbler tube and for taking gas samples. ~he bubbling height in the c~linder varies from 0.5 m to 1 metre. '~he con-sumpticn of oxygen for bubbling varies from 0.5 to 3 cu.m~hr (S~P). The analysis of gas taken from the zone above the mel~
has shown a ~00 ~er cent o~idation of sulphur with oxygen, the height of bubbling being 0.5 metre. ~he temperature of the melt varies from 300 to ~00C. Electric heating is used to commence the process at smaIl rates of air consumption (0.5 - 1 cu.m/hr, at S~P). ~e bubbler chamber comprises a cooling coil through which water is passed when sulphur boils.
A vapour-~as mixture is formed in the ~pace above the surfacc o~ the molten sulphur. The Dixture consists of sulphur vapour .
... .,.. ,. . ... - . - .. ~ .
:- ,, :, ; -. :-i .: . : :~ : :
:. . - . ... . . .
. ,, . , - : . :, , .-, .
.~. . . , ; . ~, ,., , : , . : . , - . . . - . , ~ .
, . . ., . - ~ - . -11~4791 (17.0 cu.m/hr, STP) and sulphur dioxide (3 cu.m/hr, S~P).
The obtained quantity of sulphur vapour is oxidized in the ~luidized bed o~ aluminosilicate (1 mm particles) at a tem-perature of 650 - 700C. ~he concentration of the obtained sulphur dioxide is 98 - 99 per cent by volume.
~ he capacity of the apparatus is 3000 - 3500 ~cg per sq.m per hour.
- ~5 _ .
out of sulphur and oxygen under a pressure of up to 35 atm.
~ or a better understandin~ of the invention, the follow-ing exa~ples of its practical embodiment are given by way of illustration.
~ :amPle 1 Crushed sulphur containing to 5 per cent by weight of admixtures is delivered into a melting zone by a screw feeder at a rate of 7740 kg/hr. ~ sulphur melts, it is purified, , . .
:. . . : .
. ,-.; . ~ :
, : .~. :. ...
.. . . , ,,, . , ,. . ~ : ~ . . . , : . .
.: -. . ~ . . -:. . . . .. . . . ..
~ .. .. . . .
-. . : .
. . . ... .
... .. . ...
and pumped at a temperature of 140 - 150C into t~e bubbling chamber of the ~urnace. The cross section area of the bubbl-ing chamber is about 3 s~.m, and the diameter is 2 metres.
The height of -the sulphur melt is maintained at 1 metre, (in !
the stationary conditions). Th`e bubbling chamber is a separa-te apparatus, 3.5 m high. ~he height of the separation space above the melt is 0.8 m, and of the settling zone 1.2 m. ~he consumption rate of puri~ied sulphur is 7~70 kg/hr. ~echnical~
oxygen, containlng to 2 per cent by volume of inert gas, is used in the manufacture o~ sulphur dioxide. The process is effected u~der a pressure of 10 atm and at a te.~perature of the melt equal to the boili~g point of sulphur at a given pressure (646.1C), This temperature is maintained in the bubbling chamber by the heat liberated in the reaction of oxidation of part of sulphur with ox~gen as it is bubbled through the moltsn sulphur. The quantitg of oxygen at a tem-perature of 15 - 20C used for bubbling, under stabilized process conditions, i5 626.5 ~g/hr or 438.5 cu.m/hr (at STP).
~he quantity of inert gas that is bubbled together with oxy~-en is 28.9 k~/hr or 23.1 cu.m/hr (at STP). In the startin~
period, oxygen is heated to a temperature of 350 - 400C. As the process conditions get stabilized) the oxygen reacts in the melt with the sulphur vapour. ~he reaction inside the gas bubbles is complete. A vapour-gas mixture is formed as a re-sulk in the space above the molten sulphur, the mixture con sisting of sulphur vapour (6743 kg/hr or 4720 cu.m/hr~ at _ 9 _ :; - . - , , - , ~ :
~ 47 ~
S~P), sulphur dioxide (1253 kg/~r or 433.5 cu.m/hr, at STP), and inert gases (28.9 kg/hr or 23.1 cu.m/hr, at S~P). ~he output capacity of the bubbling chamber is 2500 kg/hrx sq.m.
The vapour-gas mixture is delivered through a gas-di-stributing grating into the chamber having the inner section diameter of 1.7 m and the ~eight of 3.4 m. The chamber is an apparatus where crushed quartz, having particles sizing 1.5 mm, is fluidized. The height of the fluidized bed is Ho = 1.2, which ensures complete combustion of sulphur vapor in an oxygen stream at a te~perature of 650C. Excess h~t of the reaction is withdra~n by heat-exchangers located di-- rectly in the fluidized bed. ~he temperature of the gas at the exit ~rom the apparatus has the same value.
The quantity of oxygen to be delivered into the fluidi-zed bed should be cal~ulated on the assemption t~at the obtained sulphur dioxide will be furt-her ~ to sulphur trioxide. ~or t~is reason, the total required quantity o~
oxygen (~or ~he suimary reaction) should be delivered into the ~urnace. Sincs part of oxygen is bubbled, the total re-quired quantity o~ oxygen is 11274 kg~hr, the excess factor being ~ = 0.02. Thus, 7453.4 cuOm/br (at S~P) o~ oxygen are delivered into the fluidized bed of an inert material thro-ugh a special device. ~e composition of the gas issued from the furnace is as follows: oxyge~ 32.9 per cent by volume, ~hich is equivalent to 3905 kg/hr or 2733 cu.m/~r (a~ STP), sulphur dioxide 62.1 per cent by volume, ~lhich is equivalerlt ~ .: . . - , .: - ' .
.. . . .:
-. , ,,. ~ .
- : ~:; . . .
: : .. . ... .. -:
. :, , . . ~, . . . ;
~4791 to 14,740 kg/hr or 5159 cu.m/hr (at S~P), and inert gases 5 per cent by volume, which is equivalent to 5~8 kg/hr or 415 cu.m/hr (at STP).
~ he product1on capacity of the furnace, with respect to !~
sulphur dioxide gas having -the specified composition, is 8300 cu.m/hr (at STP).
Exam~le 2 The process is carried out as described in ~xample 1, except that the pressure is 15 atm, and the temperature o~
the molten sulphur is maintained at 650C, which is below the melting point o~ sulphur at this pressure. ~i~uid sulphur (20412 kg/hr) is evaporated in the bubbling chamber by pass-ing 1113.9 kg/hr of technical oxygen containing 15 per cent by weight of inert gas admixtures. As a result, 19~47.5 kg/hr of sulphur vapour, ~130 kg/hr of sulphur dioxide, and 49 kg/br of nitrogen are obtained in the fluid bed having the height of 1.5 m and the inner diameter of the section o~ 3.3 m. ~he vapour-gas mixture is delivered into the fluidized bed of silica gel having particles o~ 1.5 mm. The height of ~he bed is Ho = 1..2 m, the diameter o~ the apparatus in the working zone is 1~6 m, and the gas velocity, in the ~orking condi-tions, is wp = 0,75 m/second. Oxygen is delivered into the fluidized bed in the ~uantity required for complete oxidation of sulphur vapour an~ sulphur dioxide to sulphur trioxide.
~aking into account t~e excess ratio factor ~ = 0,02, this ~uantity is 30166 k~/hr, or 21,116 cu.m/hr (at STP). Technical oxygen containing 5 p~r cent by volume of inert gas is used -, - 11 ~
...!
.
,. ., r ~ 47 9 B in the process. The temperature in the fluidized bed~ ~
maintained at 650C~ The ~ollowing products are obtained at the exit from the furnace:
sulphur dioxide 40,824 kg/~r, or 14,290 cu.~/hr (at STP), oxygen 10,819 kg/hr, or 7571 cu.m/hr (at STP), nitrogen 1437 kg/hr, or 1149 cu.m/hr (at STP).
~he composition o~ sulphurous acid gas i8:
S2 62.1 per cent by volume 2 32.g per cent bg volume N2 5 per cent by volume.
EscamPle ~
~ he process i~ realized as de3cribed in Example 1, except that the pressure is 25 atm, and the temperature o~
the molten sulphur in the bubbling chamber is 650C which is below the melting point of sulphur at this pressure.
EXcess heat is withdrawn by heat-exchangers that are located directly in the molten sulphur bed.
~ iquid sulphur having the temperature o~ 140 - 150~C is delivered i~to the bubbling chamber at a rate of 30234 kg/hr The height of the molten sulphur bed is 1.5 metre. ~he diame-ter of the apparatus is 3 metres, and its height is 16 me~res.
Technical oxygen is delivered into the apparatus under a pressure of 25 atm at a rate o~ 4559.9 kg/hr. ~he amount of delivered nitro~en is 20 kg/hr.
~ .
- - . .. - . . ........... . . . .
~ - - , - . .. , 11~4791 , The gaseous mixture discharged ~rom the bubbli~g cham-ber consists of sulphur dioxide (9120 kg/hr, which is 18.4 per cent by volume), sulphur vapour (25675 kg/hr, 81.2 per cent by ~olume) and inert gases (20 kg/hr, 0.42 per cent by volume). ~he mixture is delivePed into the ~luidized bed of silica gel (particle size, 1.5 mm). Technical oxygen contain-ing nitrogen (183.5 kg/hr) is delivered in~o the fluidized bed at a rate of 41,699 kg/hr. Sulphur vapour is completely oxidized in the ~.~uidized bed at a temperature of 650C, which is maintained at this point by withdrawing excess heat from the fluidized bed. The resultant gas consists o~ sulphur ~ioxide, 64.95 per cent by volume (60,468.6 kg/hr), oxygen 34,55 per cent by volume (16,024 kg/hr), and inert gases, 0.5 per cent by volume (203,5 kg/hr).
~ !
'~he process is carried out under a pressure of to 35 atm on a pilot plant. ~rom a melting chamber, having a capacitg of one cubic metre, sulphur is loaded periodically into the bubbling chamber in the quantity of 0.017 cu.m. The diameter of the chamber is ~.3 m, the bed height is 1 m. ~he total de-livery of oxygen is 60 cu.m/hr (~P). ~he quantity o~ ox~ygen - spent ~or bubbling is 20 per cent o~ the to~al quantity o~
oxygen. ~he production capacity of the svaporator is 130 kg/hr, t~e intensity o~ evaporation being 2000 kg per square meter of the sur~ace per hour. ~he inert material used in t~e fluidized bed is specially treated aluminosilicate catalyst . ,.
11~4791 having particles o~ 1.5 mm. The height of the bed is - 0.5 m. ~he temperature in the ~luidized bed is mai~tain-ed at 600 - 615C. ~he composition of the gas discharged ~rom the furnace is S02 48 - 50 per cent by volume 2 ~ - 40 per cent b~ volume S03 1.8 - 2 per ce~t by volume.
inert gases to make 100 per cent.
Example 5 ~ he process is carried out on a pilot plant under atmosp~eric pressure Pure sulphur is loaded periodically into a cylindrical apparatus, having the diameter of 0.008 m and a height o~ 1.2 m, and provided with an ex*ernal electric heater. ~he cover of the apparatus has t~o connections, for a bubbler tube and for taking gas samples. ~he bubbling height in the c~linder varies from 0.5 m to 1 metre. '~he con-sumpticn of oxygen for bubbling varies from 0.5 to 3 cu.m~hr (S~P). The analysis of gas taken from the zone above the mel~
has shown a ~00 ~er cent o~idation of sulphur with oxygen, the height of bubbling being 0.5 metre. ~he temperature of the melt varies from 300 to ~00C. Electric heating is used to commence the process at smaIl rates of air consumption (0.5 - 1 cu.m/hr, at S~P). ~e bubbler chamber comprises a cooling coil through which water is passed when sulphur boils.
A vapour-~as mixture is formed in the ~pace above the surfacc o~ the molten sulphur. The Dixture consists of sulphur vapour .
... .,.. ,. . ... - . - .. ~ .
:- ,, :, ; -. :-i .: . : :~ : :
:. . - . ... . . .
. ,, . , - : . :, , .-, .
.~. . . , ; . ~, ,., , : , . : . , - . . . - . , ~ .
, . . ., . - ~ - . -11~4791 (17.0 cu.m/hr, STP) and sulphur dioxide (3 cu.m/hr, S~P).
The obtained quantity of sulphur vapour is oxidized in the ~luidized bed o~ aluminosilicate (1 mm particles) at a tem-perature of 650 - 700C. ~he concentration of the obtained sulphur dioxide is 98 - 99 per cent by volume.
~ he capacity of the apparatus is 3000 - 3500 ~cg per sq.m per hour.
- ~5 _ .
Claims (4)
1. A method of preparing sulphur dioxide comprising melting sulphur, bubbling oxygen through the molten sulphur to evaporate the sulphur, allowing the formed sulphur vapour to pass into a fluidized bed of an inert material, oxidizing the sulphur vapour in the fluidized bed by means of a separate supply of oxygen fed to the fluidized bed, and subsequently isolating the end product.
2. A method as claimed in claim 1, in which sulphur is evaporated by bubbling oxygen through molten sulphur at a temperature at which sulphur boils.
3. A method as claimed in claim 1, in which the sulphur is evaporated and the sulphur vapour is oxidized, under a pressure of from 1 to 35 atmospheres.
4 A method as claimed in any of claims 1 to 3, in which quartz sand, silica gel or aluminosilicate is used as the inert material of the fluidized bed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA288,474A CA1104791A (en) | 1977-10-06 | 1977-10-06 | Method of preparing sulphur dioxide |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA288,474A CA1104791A (en) | 1977-10-06 | 1977-10-06 | Method of preparing sulphur dioxide |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1104791A true CA1104791A (en) | 1981-07-14 |
Family
ID=4109736
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA288,474A Expired CA1104791A (en) | 1977-10-06 | 1977-10-06 | Method of preparing sulphur dioxide |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1104791A (en) |
-
1977
- 1977-10-06 CA CA288,474A patent/CA1104791A/en not_active Expired
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