CN102659117A

CN102659117A - Method for reinforcing fluorine absorption in mass transfer process

Info

Publication number: CN102659117A
Application number: CN2012101418487A
Authority: CN
Inventors: 周智武; 杨毅; 赵建勇; 饶轶晟; 刘海; 姚石林
Original assignee: Wengfu Group Co Ltd
Current assignee: Wengfu Group Co Ltd
Priority date: 2012-05-09
Filing date: 2012-05-09
Publication date: 2012-09-12

Abstract

The invention discloses a method for reinforcing fluorine absorption in the mass transfer process. According to the method, an absorption tower with a rotary filling bed is used as absorption equipment. The method comprises the following steps that secondary steam containing fluorine is fed from the lower part of the absorption tower, flows upwards from the bottom of the rotary filling bed and is subjected to countercurrent washing with circulating absorption liquid from a circulating liquid tank in the rotary filling bed to absorb SiF4 and HF which are contained in the secondary steam; the washed circulating absorption liquid enters a settling section on the lower part, and the settled circulating absorption liquid enters a circulating tank, is pressurized by a circulating pump and returns the absorption tower to perform circulating absorption; qualified fluosilicic acid circulating liquid is conveyed to produce fluosilicic acid; and absorbed tail gas is discharged out of the top to enter a tail gas defoamer, and the defoamed tail gas is discharged to atmosphere. By the method, the defect of the original technology is overcome, the absorption rate of the fluorine is improved greatly, the high-concentration fluosilicic acid can be produced, and absorption equipment is convenient to maintain and clean and low in cost; and the method is suitable for enterprises for producing phosphoric acid by a wet method.

Description

A kind of reinforcing mass transfer process absorbs the method for fluorine

Technical field

The present invention relates to fluorine, specifically, relate to the absorption of fluorine.

Background technology

In the Wet-process Phosphoric Acid Production process, Phosphoric Acid Concentration is that dilute phosphoric acid is boiled off moisture in flashing chamber or evaporator room, contains SiF in the secondary steam that evaporation produces ₄And HF, from the needs that reclaim the fluorine resource and the needs of environment protection, must be with the SiF in the process ₄Absorb with HF and to get off to process the sub product silicofluoric acid.Traditional method be in tower with its gas of water washing, make water, SiF ₄Reaction generates silicofluoric acid with HF, but this method fluorine recovery is low, not only causes the wasting of resources, also also has the fluorinated tail gas discharging.

Through retrieval, the one Chinese patent application part that relates to the recovery of phosphorous chemical industry fluorine only has ZL94116682.1 number " extruding fluorine absorbing process ", No. 200610125005.2 " the phosphorus fluorine method for absorbing and separating of kiln-process phosphoric acid ", No. 200710052195.4 " the phosphorus fluorine method for absorbing and separating of kiln-process phosphoric acid " and No. 200810069080.0 " method that a kind of fluorine absorbs ".But the mass transfer process of these technical schemes still is traditional method basically, and assimilation effect is undesirable.

Summary of the invention

The object of the present invention is to provide a kind of reinforcing mass transfer process to absorb the method for fluorine,, solve SiF better to overcome the deficiency of prior art ₄Absorption problem with HF.

The reinforcing mass transfer process that the contriver provides absorbs the method for fluorine; Be to realize as absorption equipment to have rotary packed bed absorption tower; Concrete way is that fluorine-containing secondary steam is sent into from the bottom, absorption tower; Up in rotary packed bed, carry out countercurrent washing through rotary packed bed bottom, absorb the SiF that contains in the secondary steam with circulating absorption solution from the circulation liquid bath ₄And HF; Washing back circulating absorption solution gets into the settling section of bottom, and the circulating absorption solution after the sedimentation gets into circulation groove, gets back to the absorption tower absorption that circulates by the recycle pump pressurization again; Silicofluoric acid content meets the requirements of circulation fluid and sends to production silicofluoride or anhydrous HF; Absorption tail gas is gone out from the top and is got into the tail gas scum dredger, and gas discharges after getting into the circulating water cooling system washing after the foam removal.

Contain SiF in the above-mentioned secondary steam ₄Be respectively 15.56% and 8.3% with the massfraction of HF.

Above-mentioned have rotary packed bed inside, absorption tower bed of packings arranged, and is placed with filler in the bed of packings, and said filler is a wire packing; The rotation of motor drives bed of packings is arranged at the bottom, and the speed control of said bed of packings rotation is at 500～800r/min; Secondary steam import and circulation fluid outlet are arranged respectively at the bottom; The circulation fluid import is arranged at top, and the top is the tail gas outlet; The circulation fluid shower nozzle that radially distributes is arranged in the bed of packings, and shower nozzle quantity is 6～8.

The above-mentioned circulation fluid silicofluoric acid that meets the requirements of is that the massfraction of silicofluoric acid is 18%～20%;

The foam-removing layer that 904 silk screens or plastic filler material are arranged in the above-mentioned tail gas scum dredger; SiF after the foam removal in the tail gas ₄Be respectively 2.75% and 1.46% with the massfraction of HF.

The contriver points out: the secondary steam that produces in the Wet-process Phosphoric Acid Production process is through above-mentioned filler in rotary packed bed; Carry out absorbing contacting with circulating cleaning solution; Because the rotation of filler; Filler is divided into liquid film as thin as a wafer with LV and tiny drop to liquid to the high shear forces of liquid, has greatly improved the fogging degree of liquid; When secondary steam through rotation, abrim during the space in as thin as a wafer the packing layer of liquid film and tiny drop, for containing SiF in the secondary steam ₄With HF and absorption liquid bigger contact area is provided, thereby has realized the reinforcement of secondary steam is absorbed.

The method of reinforcing mass transfer process absorption fluorine of the present invention has overcome the defective of original technology, has improved the specific absorption of fluorine greatly, the silicofluoric acid of ability production high density, and absorption equipment keeps in repair and clears up conveniently simultaneously, and cost is low; Be applicable to Wet-process Phosphoric Acid Production enterprise.

Description of drawings

Fig. 1 absorbs the device synoptic diagram of fluorine for the reinforcing mass transfer process.1 is the absorption tower among the figure, and 2 are the circulation liquid bath, and 3 is recycle liquid pump, and 4 is the tail gas scum dredger, and 5 is bed of packings, and 6 is shower nozzle, and 7 is phonomoter, and 8 is the secondary steam import, and 9 are the tail gas outlet, and 10 is the absorption liquid import, and 11 are the absorption liquid outlet, and 12 is vapor pipe.

Embodiment

The phosphoric acid by wet process device of certain company adopts the inventive method to absorb the SiF that contains in the secondary steam of evaporation generation ₄And HF.This method is to realize as absorption equipment to have rotary packed bed absorption tower.

Concrete way is: will contain SiF ₄Be respectively 15.56% and 8.3% secondary steam with the massfraction of HF and send into, up in rotary packed bed, carry out countercurrent washing, absorb the SiF that contains in the secondary steam with circulating absorption solution from the circulation liquid bath through rotary packed bed bottom from the bottom, absorption tower ₄And HF; Washing back circulating absorption solution gets into the settling section of bottom, and the circulating absorption solution after the sedimentation gets into circulation groove, gets back to the absorption tower absorption that circulates by the recycle pump pressurization again; The silicofluoric acid massfraction discharges after 18% in the liquid to be recycled, and discharging back circulation fluid is sent to and produced silicate or anhydrous HF; Absorption tail gas is gone out from the top and is got into the tail gas scum dredger, and gas discharges after getting into the circulating water cooling system washing after the foam removal.

The diameter on absorption tower is 2800mm, is 1800 mm highly, and there is bed of packings inside, is placed with 3m in the bed of packings ³Wire packing, modes of emplacement is even layout; The rotation of motor drives bed of packings is arranged at the bottom, and the speed control of bed of packings rotation is at 600r/min; Secondary steam import and circulation fluid outlet are arranged respectively at the bottom; The circulation fluid import is arranged at top, and the top is the tail gas outlet; 6 circulation fluid shower nozzles that radially distribute are arranged in the bed of packings.

The foam-removing layer that 904 silk screens and plastic filler are arranged in the scum dredger; SiF after the foam removal in the tail gas ₄Be respectively 2.75% and 1.46% with the massfraction of HF, foam removal efficient is 80%.

The capacity of circulation groove is 30 m ³

Claims

1. the method for a reinforcing mass transfer process absorption fluorine is characterized in that this method is to realize as absorption equipment that to have rotary packed bed absorption tower concrete way is with containing SiF ₄Be respectively 15.56% and 8.3% secondary steam with the massfraction of HF and send into, up in rotary packed bed, carry out countercurrent washing, absorb the SiF that contains in the secondary steam with circulating absorption solution from the circulation liquid bath through rotary packed bed bottom from the bottom, absorption tower ₄And HF; Washing back circulating absorption solution gets into the settling section of bottom, and the circulating absorption solution after the sedimentation gets into circulation groove, gets back to the absorption tower absorption that circulates by the recycle pump pressurization again; The silicofluoric acid massfraction is that 18%～20% circulation fluid is sent to and produced silicofluoride or anhydrous HF; Absorption tail gas is gone out from the top and is got into the tail gas scum dredger, and gas discharges after getting into the circulating water cooling system washing after the foam removal.

2. the method for claim 1 is characterized in that saidly having rotary packed bed inside, absorption tower bed of packings being arranged, and is placed with filler in the bed of packings, and said filler is a wire packing; The rotation of motor drives bed of packings is arranged at the bottom, and the speed of rotation of said bed of packings is controlled at 500～800 r/min; Secondary steam import and circulation fluid outlet are arranged respectively at the bottom; The circulation fluid import is arranged at top, and the top is the tail gas outlet; The circulation fluid shower nozzle that radially distributes is arranged in the bed of packings, and shower nozzle quantity is 6～8.

3. the method for claim 1 is characterized in that having in the said tail gas scum dredger foam-removing layer of 904 silk screens or plastic filler material; SiF after the foam removal in the tail gas ₄Be respectively 2.75% and 1.46 % with the massfraction of HF.