CN104760937A

CN104760937A - Method for separating SO2 and HCl by extractive rectification

Info

Publication number: CN104760937A
Application number: CN201510135038.4A
Authority: CN
Inventors: 汤志刚; 费维扬; 郭栋
Original assignee: Tsinghua University
Current assignee: Tsinghua University
Priority date: 2015-03-26
Filing date: 2015-03-26
Publication date: 2015-07-08
Anticipated expiration: 2035-03-26
Also published as: CN104760937B

Abstract

The invention belongs to the technical field of chemical engineering, and particularly relates to a method for separating SO2 and HCl by extractive rectification. The method comprises the following steps: adding a raw gas containing SO2 and HCl from the middle part of an extractive rectification tower; and under the action of watery added from the top of the extractive rectification tower, obtaining SO2 gas from the tower top and obtaining hydrochloric acid from the tower bottom. The method can obtain the SO2 gas with the HCl content of less than 0.1 wt% from the tower top and obtain the hydrochloric acid with the concentration of not higher than 20 wt% and the SO2 content of less than 0.1 wt% from the tower bottom. Compared with the common HCl multistage absorption technique in industry at present, the method provided by the invention greatly lowers the SO2 content in hydrochloric acid by 90% above. Compared with the multistage condensation process, the method reduces the equipment investment by 50% above.

Description

A kind of employing separation of extractive distillation SO 2with the method for HCl

Technical field

The invention belongs to genus technical field of chemical engineering, particularly one adopts separation of extractive distillation SO ₂with the method for HCl.

Background technology

Containing SO ₂be common in the production process of pharmaceutical intermediate with the mixed gas of HCl, this mixed gas pungency is large, corrodibility is strong, need to recycle, otherwise great harm is caused to environment.

Current industrial comparatively conventional method absorption process and cold method both at home and abroad.Absorption process adopts the HCl in water absorption mixed gas, but due to SO ₂also the certain solubility had in water, often containing massfraction in the hydrochloric acid that therefore water absorption HCl is formed is the SO of about 1% ₂, pungency is very large, cannot carry out follow-up comprehensive utilization.Cold method utilizes SO under low temperature ₂the feature of easy condensation is separated after mixed gas cooling, but SO ₂condensing temperature, lower than-10 DEG C, needs extra refrigeration to be separated; Single condensation separation effect is undesirable simultaneously, and need stage trapping, facility investment and running cost are all higher.

Summary of the invention

For existing absorption process and the not good deficiency of cold method separating effect, the invention provides and a kind ofly adopt separation of extractive distillation SO ₂with the method for HCl, improve separating effect, simplify and congratulate, reduce separation costs.

A kind of employing separation of extractive distillation SO ₂method with HCl, comprises the steps:

Containing SO ₂add in the middle part of extractive distillation column with the unstripped gas of HCl, under the effect of the water added from extracting rectifying top of tower, overhead extraction obtains SO ₂gas, tower reactor obtains hydrochloric acid.

Described containing SO ₂with SO in the unstripped gas of HCl ₂massfraction be 5% ~ 95%.

Described containing SO ₂be 5% ~ 95% with the massfraction of HCl in the unstripped gas of HCl.

Mode overflow from sparger for sprinkling or dependence gravity that described water adds from extracting rectifying top of tower.

Add the quality of water in same time and add containing SO ₂be (1:10) ~ (10:1) with the ratio of the unstripped gas quality of HCl.

It is 20 DEG C ~ 30 DEG C that described tower top temperature controls.

It is 105 DEG C ~ 110 DEG C that described bottom temperature controls.

Beneficial effect of the present invention is:

The inventive method can obtain from overhead extraction the SO that HCl content is less than 0.1% (wt) ₂gas, tower reactor obtains SO ₂content is less than the concentration of 0.1% (wt) not higher than the hydrochloric acid of 20% (wt).The inventive method compared with current industrial conventional multistage absorption HCl technique, SO in hydrochloric acid ₂content significantly reduces by more than 90%; Compare with multi-stage condensing method, facility investment reduces more than 50%.

Accompanying drawing explanation

Fig. 1 is that the present invention adopts separation of extractive distillation SO ₂with the method process flow sheet of HCl.

Embodiment

Not enough for prior art, the invention provides a kind of employing separation of extractive distillation SO ₂with the method for HCl, below in conjunction with the drawings and specific embodiments, the present invention will be further described.

Embodiment 1

Containing SO ₂with the mixed gas feed of HCl, temperature is 30 DEG C, and feedstock amount is 5026kg/h, and composition (wt%) is as follows:

SO ₂63.73

HCl 36.27

The flooding quantity that tower top adds water is 8106.75kg/h, and temperature is 25 DEG C.

Controlling tower top temperature is 25 DEG C, and overhead product produced quantity is 2533.75kg/h, and overhead extraction product composition (wt%) is as follows:

SO ₂99.34

HCl 0.0537

H ₂O 0.6063

Controlling bottom temperature is 107.5 DEG C, and tower kettle product produced quantity is 10598.95kg/h, and tower reactor extraction product composition (wt%) is as follows:

SO ₂0.0734

HCl 17.199

H ₂O 82.7276

。

Embodiment 2

SO ₂63.73

HCl 36.27

The flooding quantity that tower top adds water is 8205.5kg/h, and temperature is 30 DEG C.

Controlling tower top temperature is 28 DEG C, and overhead product produced quantity is 2535.5kg/h, and overhead extraction product composition (wt%) is as follows:

SO ₂99.27

HCl 0.0837

H ₂O 0.6466

Control bottom temperature 107.2 DEG C, tower kettle product produced quantity is 10696kg/h, and tower reactor extraction product composition (wt%) is as follows:

SO ₂0.0822

HCl 17.0431

H ₂O 82.8747

。

Claims

1. one kind adopts separation of extractive distillation SO ₂method with HCl, is characterized in that, comprises the steps:

2. one according to claim 1 adopts separation of extractive distillation SO ₂method with HCl, is characterized in that, described containing SO ₂with SO in the unstripped gas of HCl ₂massfraction be 5% ~ 95%.

3. one according to claim 1 adopts separation of extractive distillation SO ₂method with HCl, is characterized in that, described containing SO ₂be 5% ~ 95% with the massfraction of HCl in the unstripped gas of HCl.

4. one according to claim 1 adopts separation of extractive distillation SO ₂method with HCl, is characterized in that, mode overflow from sparger for sprinkling or dependence gravity that described water adds from extracting rectifying top of tower.

5. one according to claim 1 adopts separation of extractive distillation SO ₂method with HCl, is characterized in that, adds the quality of water and add containing SO in same time ₂be (1:10) ~ (10:1) with the ratio of the unstripped gas quality of HCl.

6. one according to claim 1 adopts separation of extractive distillation SO ₂method with HCl, is characterized in that, it is 20 DEG C ~ 30 DEG C that described tower top temperature controls.

7. one according to claim 1 adopts separation of extractive distillation SO ₂method with HCl, is characterized in that, it is 105 DEG C ~ 110 DEG C that described bottom temperature controls.