CN106044725A - Method for recovering sulfuric acid - Google Patents

Abstract

A method for recovering sulfuric acid comprises the following steps: 1, allowing material flow containing sulfuric acid steam and/or sulfur trioxide to be in contact with an ionic liquid absorbent in an absorption step; 2, discharging a gas basically containing no sulfuric acid steam and/or sulfur trioxide in the absorption step; 3, extracting material flow containing the ionic liquid absorbent in the absorption step, wherein the ionic liquid absorbent contains sulfuric acid; 4, allowing the material flow obtained in step 3 to go through a separation step in order to recover sulfuric acid from the ionic liquid absorbent; 5, extracting material flow containing sulfuric acid in separation step 4; and 6, extracting ionic liquid absorbent material flow containing sulfuric acid in the separation step 4, and returning the ionic liquid absorbent material flow to step 1.

Description

The method reclaiming sulphuric acid

Technical field

The present invention relates to a kind of from by sulfur dioxide unstripped gas producing the method reclaiming sulphuric acid in the device of sulphuric acid, wherein Described sulfur dioxide unstripped gas is such as from metallurgical operations and hydrogen-containing fuel such as the spent acid in petrochemical alkylation, hydrogen sulfide, sulfur Acid ammonium refuse and include the burning waste gas of Fossil fuel of heavy oil residue and petroleum coke.In particular it relates to it is a kind of Reclaim the new method of sulphuric acid, relate to the absorption step wherein using sulphuric acid and disulfate mixture as absorbent.The present invention Further relate to the equipment for reclaiming sulphuric acid from absorbent.

Background technology

Produced sulphuric acid by the waste gas in industrial operation generally to be carried out by catalytic oxidation stage, wherein SO₂It is converted into SO₃ Followed by hydration step, thus SO₃It is converted into sulfuric acid vapor.In so-called single wet method condensing steps, sulphuric acid exists subsequently Cooling step is condensed by the cooling medium indirect heat exchange with usually air.Sulphuric acid is directly condensed, it is therefore desirable to Enter this cooling step containing SO₃Stream temperature close to its dew point to avoid less desirable acid mist to be formed.If temperature mistake Height, acid will not condense, if temperature is too low, acid mist is by formation and is difficult to trap.Method containing single wet method condensing steps Another shortcoming is based on design of condenser and process conditions, and some acid mists are still released from condenser.

United States Patent (USP) describes a kind of by SO₂It is converted into SO₃Method, humid gas or H the most subsequently₂SO₄(H₂O+SO₃) In SO₃Absorbed in molten condition.H₂SO₄Absorption by allowing containing SO₃Gas bubbling by containing ammonium sulfate NH₄)₂SO₄With ammonium hydrogen sulfate NH₄HSO₄The fused mass of mixture carry out, and relate to reacting H₂SO₄+(NH₄)₂SO₄→ 2NH₄HSO₄.Subsequently by being heated to more than 350 DEG C or by electrolysis, ammonium hydrogen sulfate being converted into ammonium sulfate, ammonium sulfate afterwards Return in fused mass.Other sulfate found is Na₂SO₄And K₂SO₄.This patent does not describes the formation of acid mist and depends on sulfur The reaction of acid and sulfate generates disulfate.By disulfate be converted back into sulfate and remarkable and require costliness Reason, the most at high temperature, as when using ammonium sulfate or electrolysis higher than heat treatment at a temperature of 350 DEG C.Additionally, acid-sulfate The existence of sulfate being not suitable in mixture, sulfate increases the melt temperature of fused mass.Ammonium sulfate fusing point is higher than 300 DEG C And contain only the ammonium sulfate of 20wt% ammonium sulfate and ammonium hydrogen sulfate mixture ground fusing point higher than 200 DEG C (L.Cambi, G.Bozza, Ann.Chim.Appl.13 (1923), 221).

Summary of the invention

It is an object of the invention to provide a kind of from containing SO₃Gas in reclaim the method for sulphuric acid, the method with by SO₃Turn Turn to sulfuric acid vapor and can better control over compared with the conventional method of cooling medium indirect heat exchange condensation in cooling step The formation of acid fused mass.

It is a further object to provide a kind of from containing SO₃Gas in reclaim the method for sulphuric acid, including simple Sulfuric acid absorption and from absorbent, reclaim sulphuric acid and without using expensive process step, such as at the heat under electrolysis or high temperature Reason.

Present invention achieves these and other objects.

Thus, we provide a kind of method reclaiming sulphuric acid, including:

A logistics containing sulfuric acid vapor and/or sulfur trioxide is connect in absorption step by () with ionic liquid absorbent Touching, its ionic liquid absorbent comprises the mixture of disulfate and sulphuric acid, and described disulfate includes in following salt At least one: R₃NHHSO₄、LiHSO₄、NaHSO₄、KHSO₄、RbHSO₄、CsHSO₄, wherein R=H-, alkyl, aromatic radical, and In mixture, the content of sulphuric acid is 5 to 90wt%；

B () discharges the gas being substantially free of sulfuric acid vapor and/or sulfur trioxide from described absorption step；

C () discharges the logistics containing ionic liquid absorbent from described absorption step, described ionic liquid absorbs Containing sulphuric acid in agent；

(d) allow the logistics in step (c) by separating step, thus by this ionic liquid absorbent reclaims sulphuric acid；

E () discharges rich vitriolated logistics from separating step (d)；

F () discharges ionic liquid absorbent stream from separating step (d), wherein this ionic liquid absorbent contains Sulphuric acid, and this logistics is returned absorption step (a).

Term " sulphuric acid " (H in this patent detailed description₂SO₄) and " sour " be used interchangeably.

Term used herein comprises SO₃And/or H₂SO₄" humid gas " refer to containing SO₃And/or H₂SO₄Gas, its Mole ratio H₂O/SO₃At least 1.05.It is also contemplated that sulphuric acid can also be represented as reacting H₂SO₄=SO₃+H₂O。

The logistics containing sulfuric acid vapor and/or sulfur trioxide entering absorption step is that temperature is 300 DEG C to 600 DEG C scopes Gas, depend on that this logistics is from SO₂Off-take point in changer.Preferably, should be containing sulfuric acid vapor and/or sulfur trioxide Stream temperature is 350 DEG C, and from conventional SO₂This logistics that the catalytic bed of the 4th and most end in transducer is taken out is corresponding. From conventional SO₂The stream temperature that the first catalytic bed in transducer is taken out is close to 600 DEG C.

Made it possible to from suction by the existence of sulphuric acid component in the ionic liquid absorber blend extracted in absorption step Receive simple separation acid in other component of agent, thus provide a kind of method reclaiming acid, the process eliminate expensive height Temperature regeneration of sulfuric acid process or the needs of electrolysis, and need both when additionally processing pure disulfate logistics.Acid may be Water is absorbed at a temperature of failed to condensation so that be easier the process reclaiming acid from ionic liquid absorbent subsequently In obtain the acid of low water content.

Ionic liquid absorbent includes that the mixture of disulfate and sulphuric acid, described disulfate include in following salt At least one: R₃NHHSO₄、LiHSO₄、NaHSO₄、KHSO₄、RbHSO₄、CsHSO₄, wherein R=H-, alkyl, aromatic radical, and In mixture, the content of sulphuric acid is 5wt% to 90wt%, preferably 15wt% to 60wt%.Thus, enter in step (a) and absorb The ionic liquid absorbent of step can comprise 10wt% to 50wt%, preferably 20wt% to 40wt%, generally about 30wt%, such as the sulphuric acid of 35wt%.In the step (c) of absorption step, the sulfuric acid content in absorbent is more than step (a) Amount, preferably 15wt%-80wt%, more preferably 30wt%-50wt%, typically about 40wt%.Preferably, absorbent is NaHSO₄Or KHSO₄, more preferably ammonium hydrogen sulfate (R=H).Ionic liquid absorbent may contain content further and not surpass Crossing the pyrosulfate of 5wt%, it can be dehydrated by disulfate and be formed.

Present in ionic liquid absorbent, disulfate is for reducing the vapour pressure of sulphuric acid above condensation mutually, to beat Opening " temperature window ", it is by the condensation temperature of acid and occurs that the difference of gas phase temperature that acid mist formed defines.That is, may be in acid Temperature condensation acid on dew point.Therewith, it is easier to avoid acid mist to be formed or at least compared with traditional wet absorption method Reduce the formation of acid mist.Additionally, because acid is absorbed in the liquid medium with the biggest thermal capacitance, it becomes possible to use ionic Liquid removes heat, therefore at hot acid in heating surface condensation to generate under conditions of sulphuric acid without traditional for total gas The large heat exchanger of flow operation.

By using the absorbent that wherein sulfate and acid exist as mixture to process containing SO₃And/or H₂SO₄Gas Body, additionally it is possible to use stripping liquid to absorb at a temperature of as little as 50 DEG C.This makes technological operation be easier to, because inhaling Receiving agent can be by transport pump.Without expensive heating be maintained at whole during absorbent be in liquid.Such as, not sulfur acid Ammonium hydrogen sulfate fusing point higher than 140 DEG C, but along with sulfuric acid content increases, the fusing point of mixture declines the biggest.Such as, ammonium hydrogen sulfate It is about 50 DEG C with the fusing point of 50: 50 molar mixtures of sulphuric acid.Can be passed to comprise institute with the contact process of described humid gas The melter of the ionic liquid absorbent stated and carry out.Preferably, step (a) will contain the thing of ionic liquid absorbent Conductance enters to have loaded the tower of inert substance or is simply led into spray column.In inert substance and packed column and liquid extraction tower The material type character used is similar, such as antiacid ceramic raschig rings or saddle.

Containing SO₃And/or H₂SO₄Humid gas logistics enter absorption step time normally about 350 DEG C.In the middle temperature of absorption step Degree will rise, and the temperature of the logistics containing absorbent in separating step (d) subsequently somewhat reduces.Therefore, in the present invention Another embodiment in, the return logistics in step (f) was preferably cooled to about before entering absorption step (a) 150 DEG C or lower.Preferably, the absorbent temperature in absorption step (a) at 100 DEG C to 350 DEG C, more preferably 150 DEG C to 300 DEG C Scope.In these temperature ranges, operation ensure that absorbent exists with liquid, and unrelated with sulphuric acid amount in absorbent, And it is easier to make absorbent enter absorption step by spray.

Sulphuric acid in the sulphuric acid extracted by absorption step (a) and disulfate mixture needs by making containing sulphuric acid and sulphuric acid The logistics of hydrogen salt mixture is regenerated by separating step (d).Separate because the disulfate in mixture is a kind of needs Additive.Sulphuric acid is generally recovered by distillation and concentration acid.Such as by blood pressure lowering and can be by sulphuric acid with logistics indirect heat exchange It is maintained at its boiling temperature.This need the biggest heat demand so that acid be maintained at its boiling temperature and distill in unit special The high corrosive environment of acid boiling to be kept out by material.In the present invention, separating step (d) is distilled by decompression (vacuum) and completes. The vapour pressure of sulphuric acid is reduced to the level corresponding to the pure acid of simple condensation by the disulfate in ionic liquid absorbent, and ratio is greatly Low 30 DEG C to 200 DEG C under air pressure.Thus, contrary with traditional method, supply without external heat in distillation, because containing sulphuric acid The thermal capacitance of the mixture of hydrogen salt is used for distilling out acid.

In preferred embodiments, the logistics containing ionic liquid absorbent is made to comprise inertia by one or more Contact material bed is by the vacuum chamber of outside cooling thus distills.Inertia contact material can be configured in vacuum chamber The fixed bed in portion.This makes it possible to spray on big region, surface liquid-absorbant, and sulphuric acid can be from this region, surface Evaporation, and outside cooling is for cooling down the surface in vacuum chamber, the acid of evaporation can cool down on a surface and separate.Inertia Contact material is similar to the material type character used in packed column and liquid extraction tower, such as antiacid ceramic raschig rings or Saddle.Then sulfuric acid vapor condenses on the cooling surface of vacuum chamber, and the sulphuric acid of condensation is as the sulfur being substantially free of disulfate Acid logistics is taken, and acid concentration is 97wt% or preferably 99wt% or higher, corresponding to concentration (98.5wt%) more than azeotropic mixture. After the evaporation acid of inertia contact material bed, remaining acid disulfate mixture is extracted bottom bed and makes it return Return absorption step.

In another embodiment of the present invention, before step (a), containing SO₂Unstripped gas at least through one Catalytic bed, SO in catalytic bed₂It is converted into SO₃With the sulfuric acid vapor described in formation and/or sulfur trioxide logistics.Preferably, described Sulfuric acid vapor and/or sulfur trioxide logistics be from catalysis SO₂The logistics that the last bed of converter extracts, wherein by containing SO₂Raw material through the passage of many catalytic bed by SO₂It is converted into SO₃, interlayer cooling is with from the balance restriction of heat release simultaneously Reaction: SO₂+1/2O₂=SO₃Removal heat.In another embodiment of the present invention, described sulphuric acid and/or sulfur trioxide thing Stream is for by catalysis SO₂The logistics that any bed of converter extracts, preferably by catalysis SO₂The bed second from the bottom of converter extracts Logistics.By removing product before passing through subsequent catalyst bed in logistics sulphuric acid and/or sulfur trioxide exhausted, at many Layer (at least one bed) catalysis SO₂Extract sulphuric acid between the bed of converter and/or sulfur trioxide improves above-mentioned balance limit The SO of system₂The total conversion converted.

A further embodiment of the present invention includes a kind of method, wherein allows containing SO before step (a)₂Unstripped gas By at least one catalytic bed so that SO₂It is converted into SO₃With the sulfuric acid vapor described in formation and/or sulfur trioxide logistics, and will In step (e), rich vitriolated logistics makes SO by subsequent catalyst bed₂It is converted into SO₃。

Thus, the method for the present invention can be as SO₂Intermediate absorption process between the catalytic bed of converter, is preferable over down Between several second and last catalytic bed, generally in SO₂Between third and fourth catalytic bed of converter.The present embodiment has There are many advantages.Generally by will be from SO₂The hot process gas of converter bed is cooled to the inlet temperature of intermediate absorber to be come Intermediate absorber is worked, and this inlet temperature is generally about 300 DEG C.Acid mist (or anhydrous SO₃) absorbed and process gas Body is cooled to about 120 DEG C or the lower minimum possible vapour pressure to reach outside absorber, and this is to being avoided process gas outlet Formation acid mist is critically important.So process gas from purified (without the acid mist) of intermediate absorber is entering last catalysis Bed, such as catalysis SO₂Must be reheated to about 380 DEG C before 4th bed of converter.The application of the invention Technique, as intermediate absorption step, may absorb the acid steaming of 95-98% at a temperature of such as 200 DEG C or higher at a relatively high absorption Gas, thus process gas will be without acid mist.Higher process gas temperature can be kept simultaneously, thus inhale in the middle of traditional Receive step, continue operation after entering, such as SO₂Higher process gas temperature it is able to maintain that before the last catalytic bed of converter Degree, the wherein temperature in conventional suction step the most about 100 DEG C, thus entering SO₂Need before the last catalytic bed of converter Want high thermic load, so that the process gas from intermediate absorber is heated to about 380 DEG C.

Present invention also offers a kind of equipment reclaiming sulphuric acid from the mixture stream passes containing sulphuric acid and additive, this sets Standby for vacuum chamber, wherein contain the described mixture of acid via vacuum chamber entrance, by being arranged in the inertia contact material of chamber interior At least part of sulphuric acid in material bed, and mixed vapour evaporates in bed, and the acid wherein evaporated is left bed and flowed to room Cooling surface, and be condensed into the sulfuric acid stream of concentration and discharged vacuum chamber by the first outlet, wherein collecting basic from bed It is also discharged from chamber by the sulphuric acid of upper liquid and additive agent mixture by the second outlet.

The equipment of the present invention can be used for the additive in the mixture containing sulphuric acid, and this additive can reduce the steam of sulphuric acid Pressure.The mixture of sulphuric acid and additive is preferably ionic liquid absorbent, is made up of disulfate and sulphuric acid, described sulphuric acid Hydrogen salt includes at least one in following salt: R₃NHHSO₄、LiHSO₄、NaHSO₄、KHSO₄、RbHSO₄、CsHSO₄, wherein R= In H-, alkyl, aromatic radical, and mixture, the content of sulphuric acid is 5wt% to 90wt%, preferably 15wt% to 80wt%, as 30wt% to 50wt%, typically about 40wt%.

By making the acid evaporation of the equipment ionic liquid absorbent from the present invention, chamber wall and hot disulfate Only directly contact after acid is evaporated.The mainly evaporation of the acid that thermal insulation is carried out makes temperature reduce, such that it is able to vacuum chamber with Upstream device uses highly desirable material, such as politef pipeline, graphite and enamel.These materials will not be by hydrogen sulfate Salt corrosion but cannot be used for the temperature higher than 250 DEG C-300 DEG C.In the present invention, remaining ionic by extract bottom bed Liquid mixture is cooled to ratio lower temperature when not having sour adiabatic evaporation to occur, thus can be in special upstream device Use politef, graphite and enamel.This owing to preventing in process operation potential need to change parts or equipment and draws The plant downtime of the Expenses Cost risen is advantageous particularly.

Vacuum chamber is preferably in the form of flash distillation distillation chamber, and operation pressure is 0.01mbar to 100mbar, preferably 0.1mbar To 10mbar.The outside of room is cooled directly with water to provide the chamber surface of cooling, the locular wall face i.e. cooled down.External water cools down preferably by wrapping The cooling jacket of peripheral cell provides.Combination as selection, cooler pan or cooling jacket and cooler pan can provide outside cooling. The acid of inertia contact material bed evaporation is in indoor radial direction or moves upward, and contacts with the cooling wall of room.After acid condensation The first outlet declining and passing through along cooling wall liquid film bottom room is discharged with the sulfuric acid stream of more than 99wt%.Contact in inertia Material bed bottom, can arrange collecting region with trapping disulfate and unevaporated acid.Outlet is set in collecting region to reclaim Acid disulfate mixture.Inertia contact material bed is preferably arranged with fixed bed form in compartment with basket in reactor Row, and spaced apart with reactor wall.This prevents the corrosive acid-disulfate mixture of heat from directly contacting with chamber wall.Acid- Disulfate mixture inlet is preferably positioned on bed top.

Accompanying drawing is sketched

Fig. 1 shows the flow chart of the inventive method.

Fig. 2 shows the equipment schematic diagram reclaiming sulphuric acid the absorbent after absorption step.

Detailed Description Of The Invention

The method of the present invention is as shown in Figure 1.Feed stream 1 is introduced into by bottom the convection tower filled, and in tower, acid is close Absorbed by ionic liquid under atmospheric pressure.There is the ionic liquid logistics 3 by absorbing sulphuric acid and be admitted to adiabatic flash room 11, The most there acid flashed off from ionic liquid mixture and be condensed into logistics 4 12 times in decompression (vacuum).Flash distillation The ionic liquid logistics 5 of heat out was cooled to logistics 6 subsequently before sending absorption tower 10 back in cooler 13.Conveying thing The transfer line of stream 3 operates under absorption pressure.This method has 2 product streams: contain less than 5, preferably shorter than 1ppmv sulphuric acid Purification gas 2 and have 97%, the sulfuric acid stream 4 of preferably more than 99wt% acid concentration.

With reference to such as Fig. 2, it is illustrated that reclaim the vacuum chamber 11 of sulphuric acid from absorbent, wherein contain logistics 3 warp of absorbent Entered the bed 16 of inertia contact material by entrance 15, the restriction of the bed of inertia contact material by basket 17 and and vacuum chamber Cooling surface (wall) 18 separates the acid leaving the evaporation from the bed annular space 19 through its motion, as pointed to vacuum Shown in the direction of arrow in locular wall face.Wall is by cold for having the chuck 20 of the current entrance of corresponding cooling medium 21 and outlet 22 But, cooling medium e.g. water.The pressure that this room is reduced by vacuum equipment 23.In inertia contact material bed 16 bottom The collecting zone 24 with outlet 25 is provided, in order to collect and to reclaim containing disulfate and the mixture of unevaporated acid, its In this mixture return absorption step.In locular wall, the sulphuric acid of condensation drops to film and is collected bottom room, by exporting 26 rows Go out.Can be also that vacuum chamber is equipped reverse V-shaped shade 27 and is suitable for vacuum holding at chamber top (above inertia contact material bed) Put the deacidification day with fog 28 of 23, to prevent acid mist sliding any in the operating process of equipment.

Embodiment

Logistics numbering is numbered corresponding to the logistics of Fig. 1.

Two examples considered all assume that 100000Nm³/ h feed stream enters absorption step at 350 DEG C.In example 1 Gas contains 6 volume %SO3 and 10 volume % water, and in example 2, gas contains 15 volume %SO₃With 20 volume % water.Table 1 is summarized The temperature of logistics and composition in the case of two kinds.

Table 1

Example 1100000Nm³/ h, containing 6 moles of %SO₃With 10 moles of % water (6 moles of %H₂SO₄With 4 moles of % water) etc. Amount thing, is received at 350 DEG C, purifies gas and is carried at 150 DEG C.The pressure of logistics 4: 0.1-0.5mbar.Logistics 234 5 6 temperature (DEG C) 150250 ＜ 250 210 150 mass velocity (ton/hr)-32,626 300 300H₂SO₄(wt%)-40 ＞ 99 34 34H₂SO₄(ppmv) 1----water content (wt%)-＜ 0.1 ＜ 1--water content (volume %) 4----NH₄HSO₄(wt%)-60 ＜ 0.1 66 66 examples 2100000Nm³/ h, containing 15 moles of %SO₃With 20 moles of % water (15 moles of %H₂SO₄With 5 moles of % water) Equivalent, received at 350 DEG C, purify gas carried at 150 DEG C.The pressure of logistics 4: 0.1-0.5mbar.Logistics 234 56 temperature (DEG C) 150250 ＜ 250 210 150 mass flowrate (ton/hr)-66,565 600 600H₂SO₄(wt%)-40 ＞ 99 34 34H₂SO₄(ppmv) 1----water content (wt%)-＜ 0.1 ＜ 1--water content (volume %) 5----NH₄HSO₄ (wt%)-60 ＜ 0.1 66 66.

Claims (10)

1. the method reclaiming sulphuric acid, including:

A logistics containing sulfuric acid vapor and/or sulfur trioxide is contacted in absorption step by () with ionic liquid absorbent, its Ionic liquid absorbent comprises the mixture of disulfate and sulphuric acid, and described disulfate includes at least in following salt Kind: R₃NHHSO₄、LiHSO₄、NaHSO₄、KHSO₄、RbHSO₄、CsHSO₄, wherein R=H-, alkyl, aromatic radical, and described In mixture, the content of sulphuric acid is 5 to 90wt%；

B () discharges the gas being substantially free of sulfuric acid vapor and/or sulfur trioxide from described absorption step；

C () extracts the logistics containing ionic liquid absorbent from described absorption step, wherein said ionic liquid is inhaled Receive in agent containing sulphuric acid；

(d) allow the logistics in step (c) by separating step, thus by described ionic liquid absorbent reclaims sulphuric acid,

E () extracts rich vitriolated logistics from separating step (d),

F () extracts ionic liquid absorbent stream from separating step (d), wherein this ionic liquid absorbent contains sulfur Acid, and this logistics is returned absorption step (a).

2. the method for claim 1, its ionic liquid absorbent contains the pyrosulfuric acid less than 5wt% further Salt.

3. the method as described in aforementioned any one claim, wherein R=H.

4. the method for claim 1, wherein in absorption step (a) temperature of absorbent 100 DEG C to 350 DEG C scopes In.

5. the method as described in aforementioned any one claim, wherein containing ionic liquid absorbent in step (a) Logistics is introduced in tower or the spray column of inert substance filling.

6. the method as described in aforementioned any one claim, wherein separating step (d) is carried out by decompression distillation.

7. method as claimed in claim 6, wherein by making the logistics containing ionic liquid absorbent pass through one or many Individual have the vacuum chamber of inertia contact material bed to carry out described distillation, and wherein said vacuum chamber is cooled down by outside.

8. the method as described in aforementioned any one claim, wherein containing SO before step (a)₂Unstripped gas by extremely A few catalytic bed, makes SO in described catalytic bed₂It is converted into SO₃With the sulfuric acid vapor described in formation and/or sulfur trioxide thing Stream, and by vitriolated for the richness of step (e) logistics by subsequent catalyst bed, in this catalyst bed, make SO₂It is converted into SO₃。

9., for reclaiming an equipment for sulphuric acid from the logistics of the mixture containing sulphuric acid and additive, wherein this equipment is true Empty room, wherein contain the described mixture of described acid via vacuum chamber entrance, by being arranged in the inertia contact of described chamber interior At least part of sulphuric acid in the bed of material, and described mixture evaporates from described room, and bed is left in the acid wherein evaporated Flow to the cooling surface of described room, and be condensed into the sulfuric acid stream of concentration, and discharged out vacuum chamber, and its by the first outlet Middle the sulphuric acid of substantially liquid and the mixture of additive collected from bed and is discharged vacuum chamber by the second outlet.

10. equipment as claimed in claim 9, wherein the mixture of sulphuric acid and additive is ionic liquid absorbent, contains Disulfate and the mixture of sulphuric acid, described disulfate includes at least one in following salt: R₃NHHSO₄、LiHSO₄、 NaHSO₄、KHSO₄、RbHSO₄、CsHSO₄, wherein R=H-, alkyl, aromatic radical, wherein in mixture, the content of sulphuric acid is 5wt% To 90wt%.