CN104692415B - A kind of evaporative crystallisation process when producing potassium nitrate to ammonium chloride - Google Patents
A kind of evaporative crystallisation process when producing potassium nitrate to ammonium chloride Download PDFInfo
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Abstract
The invention discloses a kind of evaporative crystallisation process when producing potassium nitrate to side-product ammonium chloride, belong to the evaporative crystallization technique field of solution, this evaporative crystallisation process includes multiple effect counter current falling film evaporation process and DTB flash crystallization process, i.e. ammonium chloride mother liquor is introduced into last evaporator, subsequently enter the vaporizer of an effect until carrying out heating evaporation in 1st effective evaporator, then a magma is obtained after carrying out decrease temperature crystalline during gained feed liquid pumps into DTB flash evaporation crystallizer in 1st effective evaporator and containing a thin brilliant clear liquid, clear liquid pumps in fine crystal elimination device and thin crystalline substance is carried out heating for dissolving, magma carries out thickening and obtains secondary magma and secondary clear liquid in pumping into thickener；Secondary magma centrifugal drying processes after obtaining chloride solid, secondary clear liquid entrance settler settlement treatment and obtains potassium nitrate mother solution and sedimentation liquid.The technology investment operating cost of the present invention is relatively low, product crystal even particle size distribution, quality are good.
Description
Technical field
The present invention relates to the evaporative crystallization technique field of solution, be specifically related to a kind of when producing potassium nitrate to chlorination
The evaporative crystallisation process of ammonium.
Background technology
Potassium nitrate is a kind of important Inorganic Chemicals, and the production method of potassium nitrate mainly uses in China
Ammonium nitrate and potassium chloride double decomposition conversion method, this kind of method also generates a kind of secondary while generating potassium nitrate
Product ammonium chloride, and environment can be caused by ammonium chloride exhausted liquid discharge the biggest pollution, thus it is generally required to right
Side-product ammonium chloride separates, and in general, typically requires and carry out ammonium chloride mother liquor during separating ammonium chloride
The series of steps such as evaporation, crystallization, centrifugation.
Existing ammonium chloride mother liquor evaporative crystallisation process mostly forces external circulation evaporation or economic benefits and social benefits following current strong with single-action
The form of external circulation evaporation processed is main.The technological parameter of single-action pressure external circulation evaporation method is: liquid to be crystallized
Temperature be 70 DEG C, in liquid to be crystallized, ammonium chloride concentration is 11.9%；External circulation evaporation side is forced in economic benefits and social benefits following current
The technological parameter of method is: the temperature of liquid to be crystallized is 69 DEG C, and in liquid to be crystallized, ammonium chloride concentration is 11.8%.
But in actual production, we can find that above-mentioned ammonium chloride mother liquor evaporative crystallisation process comes with some shortcomings, main
Show:
(1) steam consumption quantity is high.Single-action forces the steam consumption quantity of external circulation evaporation mode to be 1.1～1.2kg/kg
Water, economic benefits and social benefits following current forces the steam consumption quantity of external circulation evaporation mode to be 0.69～0.73kg/kg water.
(2) investment and operating cost are high.Due to the flow rate of liquid one in the heat exchanger tube of pressure external circulation evaporator
As relatively big, so forcing external circulation evaporator to be often equipped with the high-power circulating pump of big flow, low lift,
Thus considerably increase investment and operating cost.
(3) product crystal particle size distribution width, second-rate.In the end effect of pressure external circulation evaporator often
Producing crystal, when using forced circulation pump, the crystal grain in serosity will touch with the impeller of high speed rotating
Hit, cause the damage to crystal itself, the product crystal granularity of more than 80% between 0.08～0.2mm,
Lens capsule is wider, second-rate, the yield of product is relatively low；Meanwhile, in collision process,
Crystal will also result in certain abrasion to the pump housing itself, thus adds maintenance cost.
(4) for single effect evaporator, owing to heat-transfer surface is relatively small, then Jie of heat-transfer surface both sides is needed
A bigger temperature difference is held in quality guarantee, but the bigger temperature difference easily causes the local local that solution contacts with heat-transfer surface
Overheated, so that material causes accumulation on heat-transfer surface, cause the heat-transfer effect of heat-transfer surface to be deteriorated, follow-up
The amount of labour processed strengthens.
Additionally, there is also the problems such as device floor space is big.Due to existing ammonium chloride mother liquor evaporative crystallization
Production process exist above not enough so that this technique but obtains low production under conditions of high cost is run and produces
Energy.
Summary of the invention
The technical problem to be solved in the present invention is to provide the ammonium chloride evaporation knot of a kind of good product quality, low energy consumption
Brilliant technique.
For solving above-mentioned technical problem, the technical solution used in the present invention is:
A kind of evaporative crystallisation process when producing potassium nitrate to ammonium chloride, is passed through multiple-effect including by ammonium chloride mother liquor
Vaporising device utilize steam carry out process and the crystallization process of multiple effect counter current evaporation, it is characterised in that: institute
Being falling film evaporator with vaporizer, heating chamber is pipe heat exchanger, and flash evaporation crystallizer (5) is DTB
Vacuum crystallizer；
The flow direction of ammonium chloride mother liquor is: ammonium chloride mother liquor initially enters last evaporator and is evaporated, then pump
The vaporizer entering a upper effect is evaporated, until arriving 1st effective evaporator, completes evaporation from 1st effective evaporator
Concentrated solution pump into flash evaporation crystallizer (5), concentrated solution concentrates further at flash evaporation crystallizer (5) and lowers the temperature
Crystallization, is carried out in concentration process by thin with what flash evaporation crystallizer (5) was connected in flash evaporation crystallizer (5)
The clear liquid produced in flash evaporation crystallizer (5) is heated to dissolve a clear liquid by brilliant canceller (6)
In thin brilliant and return in flash evaporation crystallizer (5)；Flash evaporation crystallizer (5) is carried out concentration process produces
A raw magma pumps into and carries out thickening in thickener (7) and obtain secondary clear liquid and secondary magma, secondary magma
Enter centrifuge (8) from thickener (7) to be centrifuged separating, obtain chloride solid and centrifugal liquid, from
Heart liquid enters in mother liquor tank (9)；The secondary clear liquid overflow produced in thickener (7) enters settler (10)
Clear liquor and sedimentation liquid are clarified to obtain in interior sedimentation further, and clear liquor is that potassium nitrate mother solution is from settler (10)
Portion overflows, and sedimentation liquid is drained in mother liquor tank (9)；It is right that ammonium chloride mother liquor in mother liquor tank (9) is additionally operable to
Thickener (7) and settler (10) recoil；
Heating steam and condensation flow thereof to for: the steam of heating enters into an effect of 1st effective evaporator and adds
Hot cell (1), the condensed water produced in effect heating chamber (1) effect from effect heating chamber (1) bottom is steamed
Vapour condensation-water drain (21) is discharged；The indirect steam produced in one effect heating chamber (1) is through 1st effective evaporator
One effect separation chamber (2) enters two effects heating chamber (3) of 2nd effect evaporator, by that analogy, until end effect is evaporated
Device；Meanwhile, the steam of heating enters into fine crystal elimination device (6), and produce in fine crystal elimination device (6) is cold
Solidifying water steam condensate (SC) outlet (23) from fine crystal elimination device (6) is discharged, in fine crystal elimination device (6)
The indirect steam produced enters flash evaporation crystallizer (5) and discharges from flash distillation indirect steam outlet (24)；
Described multi-effect evaporating device is double-effect evaporation vaporizer, concretely comprising the following steps of its countercurrent evaporation: by chlorination
Ammonium mother solution is joined two effects by the stock solution charging aperture (17) on two effect heating chamber (3) tops of 2nd effect evaporator and adds
Heating evaporation is carried out in hot cell (3), and by two effects separation chamber (4) being connected with two effects heating chamber (3)
Feed liquid after two effect heating chamber (3) evaporations is carried out gas-liquid separation, two effects heating chamber (3) and two effects separate
Room (4) interior gained feed liquid is two effect feed liquids；Described two effect feed liquid parts are beaten by two effects circulating pump (13) again
Return one closed circuit of formation in two effects heating chamber (3) and be used for two effect feed liquid circulating-heating again evaporations, separately
A part two effect feed liquids by two effect punishment in advance pump (12) squeeze into an effect heating chamber (1) in carry out heating evaporation and
After effect heating chamber (1) being evaporated by effect separation chamber (2) being connected with effect heating chamber (1)
It is an effect feed liquid that feed liquid carries out gas-liquid separation, effect heating chamber (1) and effect separation chamber (2) gained feed liquid；
A described effect feed liquid part is returned in an effect heating chamber (1) by effect circulating pump (11) and is formed one
Closed circuit is for an effect feed liquid circulating-heating again evaporation, and another part one imitates feed liquid by an effect circulating pump
(11) squeeze into and flash evaporation crystallizer (5) carries out concentrate decrease temperature crystalline obtain a magma and containing thin brilliant one
Secondary clear liquid；The described clear liquid flow export from the middle part of flash evaporation crystallizer (5) flows out and by fine crystal elimination pump
(14) squeeze in fine crystal elimination device (6) and the thin crystalline substance in a clear liquid is carried out heating for dissolving, after dissolving
Secondary clear liquid back flows back into and forms a closed circuit in flash evaporation crystallizer (5)；
A described magma is squeezed into and is carried out thickening in thickener (7) and obtain two para-crystals by crystallizing discharging pump (15)
Slurry and secondary clear liquid；Secondary magma enter centrifuge (8) are centrifuged isolated chloride solid and from
Heart liquid, chloride solid is by chloride solid discharging opening (26) discharge of centrifuge (8) bottom, centrifugal liquid
Enter in mother liquor tank (9)；Secondary clear liquid entrance settler (10) carries out settling clarification and obtains sedimentation liquid and nitre
Acid potassium mother solution, sedimentation liquid enters in mother liquor tank (9), and potassium nitrate mother solution is from the nitric acid on settler (10) top
Potassium mother liquor outlet (25) flows out；
Upper and lower two fixed gases outlet it is provided with in effect heating chamber (1) in described effect heating chamber (1)
Fixed gas discharge, enter the indirect steam two effects heating chamber (3) to chlorination from effect separation chamber (2)
Ammonium mother solution heats, and fixed gas contained in two effects heating chamber (3) is respectively by two effects heating chamber (3)
The fixed gas outlet of upper and lower is discharged, and the condensed water that indirect steam is formed after heat exchange is by two effect heating
Room (3) bottom two effect indirect steam condensation-water drain (19) discharge, uncooled indirect steam enter with
Then from two effects on two effect separation chamber (4) tops in two effects separation chamber (4) that two effects heating chamber (3) are connected
Indirect steam outlet (18) is discharged；
Also include that one utilizes steam condensate (SC) to be arranged on last evaporator ammonium chloride mother liquor porch for preheating
The preheater of the ammonium chloride mother liquor of crystallization to be evaporated, preheater connects with the steam condensate (SC) outlet of last evaporator
Logical.
The present invention further improvement is that: described multi-effect evaporating device is triple effect evaporation vaporizer, and ammonium chloride is female
Liquid enters from the top of triple effect evaporator, arrives 2nd effect evaporator, 1st effective evaporator, triple effect evaporator successively
On be also equipped with the outlet of upper and lower two fixed gases.
Owing to using technique scheme, the technological progress acquired by the present invention is:
The multiple effect counter current falling film evaporation mode that the present invention uses vaporizer to be falling film evaporator, can obviously reduce steaming
Steam consumption, also contributes to reduce steam required condensation water consumption simultaneously；Crystallizer uses flash crystallization mode,
I.e. utilize vacuum to reduce the temperature of feed liquid, substantially reduce thermic load and heat exchange area, reduce equipment investment；
The outside of flash evaporation crystallizer is provided with fine crystal elimination device, can effectively eliminate in flash evaporation crystallizer contained in clear liquid
The thin brilliant impact on ammonium chloride bulk crystal granularity also improves the purification rate of ammonium chloride simultaneously；Flash evaporation crystallizer
For DTB vacuum crystallizer, the pressure head needed for the interior circulation of this crystallizer is low, the feed liquid stirring speed in crystallizer
Degree is slow, greatly reduces the collision between crystal and crystallizer, namely uses DTB flash crystallization process, can
So that product crystal even particle size distribution, product yield is high, quality is good；Mother solution in mother liquor tank is to thickener
With the recoil of settler, improve the purification rate of ammonium chloride.
It is provided with fixed gas outlet on vaporizer, efficiently solves the fixed gas impact on whole heat-transfer effect；
Falling film evaporator selected by vaporizer, and required pump flow is little, investment and operating cost is relatively low, be
Forcing external circulation evaporator investment and about the 1/2 of operating cost, meanwhile, this kind of vaporizer the most effectively eliminates
The effective heat transfer temperature loss problem caused by hydrostatic column, vaporizer pressure drop is less, in relatively low heat exchange temperature
There is higher heat transfer coefficient under difference, be suitable for use in multi-effect evaporation system；Heating chamber in vaporizer is tubular type
Heat exchanger, the feed liquid in falling film evaporator without Binding, thus reduces on the heat exchanger tube of pipe heat exchanger
Subsequent treatment；Additionally, equipment therefor of the present invention also including, one utilizes steam condensate (SC) to treat for preheating
The preheater of evaporative crystallization ammonium chloride mother liquor, can make full use of the sensible heat that steam condensate (SC) is taken out of.
The ammonium chloride evaporation and crystallization system continuous operation of the present invention, crystallization condition is stable, and product quality is homogeneous,
Production capacity exceeds several times even tens times, and ammonium chloride evaporative crystallization equipment therefor floor space compared with single effect evaporator
Little.
Accompanying drawing explanation
Fig. 1 is the present invention a kind of installation drawing to the evaporative crystallisation process of ammonium chloride when producing potassium nitrate；
In the accompanying drawings: 1, an effect heating chamber, 2, one effect separation chamber, 3, two effect heating chambers, 4, two effects point
From room, 5, flash evaporation crystallizer, 6, fine crystal elimination device, 7, thickener, 8, centrifuge, 9, mother liquor tank,
10, settler, 11, one effect circulating pump, 12, two effect punishment in advance pumps, 13, two effect circulating pumps, 14, carefully crystalline substance
Eliminate pump, 15, crystallization discharging pump, 16, mother solution pump, 17, stock solution charging aperture, 18, two effect indirect steams
Outlet, 19, two effect indirect steam condensation-water drains, 20, one effect steam inlet, 21, one effect steam condensation
Water out, 22, fine crystal elimination device steam inlet, 23, steam condensate (SC) outlet, 24, flash distillation indirect steam
Outlet, 25, potassium nitrate mother liquor outlet, 26, chloride solid discharging opening.
Detailed description of the invention
Being embodied as the evaporative crystallisation process of ammonium chloride when below in conjunction with the accompanying drawings the present invention is produced potassium nitrate
Step is described in further details:
When the present invention produces potassium nitrate, the evaporative crystallisation process to ammonium chloride includes ammonium chloride mother liquor is passed through multiple-effect
Vaporising device utilizes process and crystallization process that steam is evaporated.Vaporizer used in the inventive method
Being falling film evaporator, heating chamber is pipe heat exchanger, and flash evaporation crystallizer 5 is DTB vacuum crystallizer,
That is the multiple effect counter current evaporation mode in the inventive method is multiple effect counter current falling film evaporation mode, crystallizes
Journey is DTB flash crystallization process.
In the inventive method, the flow direction of ammonium chloride mother liquor is: ammonium chloride mother liquor initially enters last evaporator to be carried out
Evaporation, the vaporizer being then pumped into an effect is evaporated, until arriving 1st effective evaporator, in vaporising device
Steam flow for add vapours be introduced into 1st effective evaporator subsequently into 2nd effect evaporator until arrive end effect steam
Sending out device, in vaporizer, steam used is indirect steam produced by a vaporizer imitated, in vaporizer
Vapor (steam) temperature is that temperature is the highest in 1st effective evaporator, temperature is minimum in last evaporator；Molten in vaporising device
Liquid temp is that 1st effective evaporator is higher than in 2nd effect evaporator, by that analogy last evaporator temperature according to flow direction of material
Spending minimum, and vaporizer used is falling film evaporator, the feed liquid that falling film evaporator adds from top is in heat exchange
Flowing downward with membranaceous in Guan, this kind of vaporizer effectively eliminates the effective heat transfer temperature difference caused by hydrostatic column and damages
Mistake problem, vaporizer pressure drop is less, has higher heat transfer coefficient, therefore use under relatively low heat transfer temperature difference
Multiple effect counter current falling film evaporation mode not only can reduce steam consumption quantity and also reduce the consumption of condensed water needed for steam
Amount；The concentrated solution completing evaporation from 1st effective evaporator will pump in flash evaporation crystallizer 5, and concentrated solution is in flash distillation
Crystallizer 5 concentrates further and decrease temperature crystalline obtains a magma and containing a thin brilliant clear liquid, flash distillation
Crystallization mode, i.e. utilizes vacuum to reduce the temperature of feed liquid, substantially reduces thermic load and heat exchange area drops simultaneously
Low equipment investment, flash evaporation crystallizer 5 is DTB vacuum crystallizer, and DTB vacuum crystallizer is to follow in magma
Pressure head needed for ring-like crystallizer, interior circulation is low, and the feed liquid mixing speed in crystallizer is slow, such that it is able to greatly
The big collision reduced between crystal and crystallizer, crystallization process uses DTB flash crystallization, can make product crystal
Even particle size distribution, product yield is high, quality is good；Fine crystal elimination device 6 is connected with flash evaporation crystallizer 5,
Flash evaporation crystallizer 5 is carried out concentration process also can be produced in flash evaporation crystallizer 5 by fine crystal elimination device 6
The raw thin crystalline substance in a clear liquid carries out heating for dissolving, and a clear liquid after heating for dissolving returns to flash distillation knot
In brilliant device 5, fine crystal elimination device 6 not only effectively eliminates in a clear liquid contained thin brilliant brilliant to ammonium chloride entirety
The impact of body granularity and also improve the purification rate of ammonium chloride；Concentration process is carried out in flash evaporation crystallizer 5
Magma of middle generation pumps into after carrying out thickening in thickener 7 and obtains secondary clear liquid and secondary magma, secondary
Magma enters centrifuge 8 from thickener 7 and is centrifuged separating, and obtains chloride solid and centrifugal liquid, centrifugal
Liquid enters in mother liquor tank 9；The secondary clear liquid overflow produced in thickener 7 is sunk in entering settler 10 further
Fall clarifies to obtain clear liquor and sedimentation liquid, and clear liquor is that potassium nitrate mother solution overflows from settler 10 top, sedimentation liquid
Then it is drained in mother liquor tank 9；Ammonium chloride mother liquor in mother liquor tank 9 is also used for thickener 7 and settler 10
Recoil, thus improve the purification rate of ammonium chloride.
In the inventive method, heating steam and condensation flow thereof to for: the steam of heating is first into
In an effect heating chamber 1 in 1st effective evaporator, steam forms condensed water and indirect steam, an effect after heat exchange
The condensed water produced in heating chamber 1 is from effect steam condensate (SC) outlet 21 discharge of effect heating chamber 1 bottom；
One effect heating chamber 1 is connected with an effect separation chamber 2, and the indirect steam produced in an effect heating chamber 1 is through an effect
One effect separation chamber 2 of vaporizer enters in two effect heating chambers 3 of 2nd effect evaporator, by that analogy, until end
Single-effect evaporator；Meanwhile, the steam of heating enters in fine crystal elimination device 6, and steam is formed cold after heat exchange
Solidifying water and indirect steam, the condensed water produced in fine crystal elimination device 6 steam condensation from fine crystal elimination device 6
Water out 23 is discharged, and the indirect steam produced in fine crystal elimination device 6 enters in flash evaporation crystallizer 5 complete through heat exchange
Flash distillation indirect steam outlet 24 discharge on Cheng Houcong flash evaporation crystallizer 5 top.
Described multi-effect evaporating device is the double-effect evaporation vaporizer including 1st effective evaporator and 2nd effect evaporator, its
Concretely comprising the following steps of countercurrent evaporation: first, is pushed up ammonium chloride mother liquor by two effect heating chambers 3 of 2nd effect evaporator
The stock solution charging aperture 17 of end carries out heating evaporation in joining two effect heating chambers 3, and by imitating heating chambers with two
The 3 two effect separation chambers 4 being connected carry out gas-liquid separation, two effects to the feed liquid after evaporation in two effect heating chambers 3
In heating chamber 3 and two effect separation chambers 4, the feed liquid of gained is two effect feed liquids；Described two effect feed liquid parts are by two
Effect circulating pump 13 is returned and is formed a closed circuit in two effect heating chambers 3, for again following two effect feed liquids
Ring heating evaporation, another part two is imitated in feed liquid is squeezed into an effect heating chamber 1 by two effect punishment in advance pumps 12 and is heated
After one effect heating chamber 1 is evaporated by evaporation the effect separation chamber 2 being connected by imitating heating chamber 1 with
Feed liquid carries out gas-liquid separation, and the feed liquid of an effect heating chamber 1 and effect separation chamber 2 gained is an effect feed liquid.
A described effect feed liquid part is returned by an effect circulating pump 11 and is formed one in an effect heating chamber 1 and loop back
Road, for one effect feed liquid circulating-heating again evaporation, another part one imitate feed liquid by one effect circulating pump 11
Squeeze into and obtain a magma and a clear liquid, a clear liquid after flash evaporation crystallizer 5 being carried out concentrate decrease temperature crystalline
In containing thin brilliant；The described flow export containing a thin brilliant clear liquid from the middle part of flash evaporation crystallizer 5 flows out also
Squeezed in fine crystal elimination device 6 by fine crystal elimination pump 14 and the thin crystalline substance in a clear liquid is carried out heating for dissolving, molten
A clear liquid after solution will back flow back into one closed circuit of formation in flash evaporation crystallizer 5.
A magma in flash evaporation crystallizer 5 is squeezed into and is carried out thickening in thickener 7 and obtain by crystallizing discharging pump 15
Secondary magma and secondary clear liquid；Secondary magma in thickener 7 enters in centrifuge 8 and is centrifuged separating
To chloride solid and centrifugal liquid, chloride solid is by the chloride solid discharging opening 26 of centrifuge 8 bottom
Discharging, centrifugal liquid then enters in mother liquor tank 9；Secondary clear liquid in thickener 7 enters settler 10 and sinks
Obtaining sedimentation liquid and potassium nitrate mother solution after fall clarification, sedimentation liquid enters in mother liquor tank 9, and potassium nitrate mother solution is from heavy
The potassium nitrate mother liquor outlet 25 on fall device 10 top flows out.
One effect heating chamber 1 is contained within fixed gas, and an effect heating chamber 1 is provided with upper and lower two fixed gases outlet
To discharge the fixed gas of different densities size respectively, to avoid the fixed gas impact on whole heat-transfer effect；One
Effect separation chamber 2 is connected with two effect heating chambers 3, enters two two effect heating chambers 3 from an effect separation chamber 2
Ammonium chloride mother liquor in two effect heating chambers 3 is heated by secondary steam, difference contained in two effect heating chambers 3
The fixed gas of density size is discharged by the fixed gas outlet of two effect heating chamber 3 upper and lowers respectively；Two effects
The condensed water that indirect steam in heating chamber 3 is formed after heat exchange is by two effects two of two effect heating chamber 3 bottoms
Secondary steam condensate (SC) outlet 19 discharge, the uncooled indirect steam in two effect heating chambers 3 enters and adds with two effects
In the two effect separation chambers 4 that hot cell 3 is connected, go out from the two effect indirect steams on two effect tops, separation chamber 4 the most again
Mouth 18 is discharged.
Described multi-effect evaporating device is that the triple effect including 1st effective evaporator, 2nd effect evaporator and triple effect evaporator steams
Sending out vaporizer, triple effect evaporator is connected in series with 1st effective evaporator, 2nd effect evaporator, and ammonium chloride mother liquor is first
Enter from the top of triple effect evaporator, arrive 2nd effect evaporator, 1st effective evaporator, triple effect evaporation the most successively
Upper and lower two fixed gases outlet it is also equipped with to discharge the fixed gas of different densities size on device.
The present invention is falling film evaporator to vaporizer used by the evaporative crystallization of ammonium chloride when producing potassium nitrate,
The feed liquid that falling film evaporator adds from top flows downward with membranaceous in heat exchanger tube, needed for falling film evaporator
Pump flow is little, invest relatively low with operating cost, be force external circulation evaporator investment and run into
This about 1/2, meanwhile, this kind of vaporizer also effectively eliminates the effective heat transfer temperature difference caused by hydrostatic column
Loss problem, vaporizer pressure drop is less, has higher heat transfer coefficient under relatively low heat transfer temperature difference, is suitable for using
In multi-effect evaporation system；Heating chamber is pipe heat exchanger, and the feed liquid in falling film evaporator is at pipe type heat transfer
Without Binding on the heat exchanger tube of device, thus decrease subsequent treatment.During additionally, the present invention produces potassium nitrate
To the evaporative crystallization equipment therefor of ammonium chloride also includes a preheater utilizing steam condensate (SC), preheater
Be arranged on last evaporator ammonium chloride mother liquor porch and connect with the condensation-water drain of last evaporator, for
Preheat the ammonium chloride mother liquor of crystallization to be evaporated to make full use of the sensible heat that steam condensate (SC) is taken out of.
Embodiment 1
The temperature of liquid to be crystallized is 40 DEG C, and the ammonium chloride concentration in liquid to be crystallized is 16.7%, with 57390kg/h
Inlet amount enters evaporation section, and vaporising device is double-effect evaporation vaporizer.Material in vaporizer and crystallizer
State see table 1:
Feed temperature and ammonium chloride concentration in table 1 vaporizer and crystallizer
Ammonium chloride solution crystal particle mean size after evaporative crystallization technique processes is 0.15mm, and former pressure follows
Crystal particle mean size after ring type evaporative crystallization processes is 0.10mm, and new evaporative crystallisation process is than old evaporative crystallization
The crystal particle mean size of method goes out greatly nearly 0.5 times.
The device specific energy consumption of this continuous evaporative crystallization technique is 0.58kg steam/kg water, steam consumption quantity is little,
Energy consumption is low.
The plant personnel required of this continuous evaporative crystallization technique is: crystallization operation 2 people/class, takes up an area for long 18m × wide
12m, floor space is little.
Embodiment 2
The temperature of liquid to be crystallized is 30 DEG C, and the ammonium chloride concentration in liquid to be crystallized is 16.6%, with
The inlet amount of 172170kg/h enters evaporation section, and vaporising device is triple effect evaporation vaporizer, and in chlorination
Ammonium mother solution first passes through preheater preheating before entering triple effect evaporator.In vaporizer and crystallizer, the state of material is shown in
Table 2 below:
Feed temperature and ammonium chloride concentration in table 2 vaporizer and crystallizer
The device specific energy consumption of this continuous evaporative crystallization technique is 0.42kg steam/kg water, than embodiment 1
Energy consumption reduces 27.6%.
The plant personnel required of this continuous evaporative crystallization technique is: crystallization operation 3 people/class, takes up an area for long 35m × wide
18m。
Claims (2)
1. evaporative crystallisation process when producing potassium nitrate to ammonium chloride, including ammonium chloride mother liquor being passed through in multi-effect evaporating device process and the crystallization process utilizing steam to carry out multiple effect counter current evaporation, it is characterized in that: vaporizer used is falling film evaporator, heating chamber is pipe heat exchanger, and flash evaporation crystallizer (5) is DTB vacuum crystallizer；
The flow direction of ammonium chloride mother liquor is: ammonium chloride mother liquor initially enters last evaporator and is evaporated, the vaporizer being then pumped into an effect is evaporated, until arriving 1st effective evaporator, the concentrated solution completing evaporation from 1st effective evaporator pumps into flash evaporation crystallizer (5), concentrated solution concentrates and decrease temperature crystalline further at flash evaporation crystallizer (5), flash evaporation crystallizer (5) is carried out the clear liquid produced in flash evaporation crystallizer (5) is heated to dissolve thin brilliant in a clear liquid by the fine crystal elimination device (6) that is connected with flash evaporation crystallizer (5) by concentration process and returns in flash evaporation crystallizer (5)；The magma carrying out producing in concentration process in flash evaporation crystallizer (5) pumps into and carries out thickening in thickener (7) and obtain secondary clear liquid and secondary magma, secondary magma enters centrifuge (8) from thickener (7) and is centrifuged separating, obtaining chloride solid and centrifugal liquid, centrifugal liquid enters in mother liquor tank (9)；The secondary clear liquid overflow produced in thickener (7) settles further in entering settler (10) and clarifies to obtain clear liquor and sedimentation liquid, and clear liquor is that potassium nitrate mother solution overflows from settler (10) top, and sedimentation liquid is drained in mother liquor tank (9)；Ammonium chloride mother liquor in mother liquor tank (9) is additionally operable to recoil thickener (7) and settler (10)；
Heating steam and condensation flow thereof to for: the steam of heating enters into effect heating chamber (1) of 1st effective evaporator, and the condensed water produced in effect heating chamber (1) effect steam condensate (SC) outlet (21) from effect heating chamber (1) bottom is discharged；The indirect steam produced in one effect heating chamber (1) is through two effects heating chamber (3) of effect separation chamber (2) entrance 2nd effect evaporator of 1st effective evaporator, by that analogy, until last evaporator；Simultaneously, the steam of heating enters into fine crystal elimination device (6), the condensed water produced in fine crystal elimination device (6) steam condensate (SC) outlet (23) from fine crystal elimination device (6) is discharged, and the indirect steam produced in fine crystal elimination device (6) enters flash evaporation crystallizer (5) and discharges from flash distillation indirect steam outlet (24)；
Described multi-effect evaporating device is double-effect evaporation vaporizer, concretely comprising the following steps of its countercurrent evaporation: carry out heating evaporation in ammonium chloride mother liquor is joined two effect heating chambers (3) by the stock solution charging aperture (17) on two effect heating chamber (3) tops of 2nd effect evaporator, and imitate the feed liquid after heating chamber (3) is evaporated to carry out gas-liquid separation, two effects heating chamber (3) and two effect separation chamber (4) interior gained feed liquids to two being two effect feed liquids by two effects separation chamber (4) being connected with two effects heating chamber (3)；Described two effect feed liquid parts are returned by two effects circulating pump (13) again and are formed a closed circuit in two effect heating chambers (3) for two effect feed liquid circulating-heating again evaporations, it is an effect feed liquid that another part two imitate in feed liquid is squeezed into an effect heating chamber (1) by two effects punishment in advance pump (12) feed liquid after carrying out heating evaporation and being evaporated effect heating chamber (1) by effect separation chamber (2) being connected with effect heating chamber (1) to carry out gas-liquid separation, effect heating chamber (1) and effect separation chamber (2) gained feed liquid；
A described effect feed liquid part is returned by effect circulating pump (11) and is formed one closed circuit in an effect heating chamber (1) for an effect feed liquid circulating-heating again evaporation, and another part one is imitated feed liquid and squeezed into by effect circulating pump (11) and carry out concentrating decrease temperature crystalline in flash evaporation crystallizer (5) and obtain a magma and a clear liquid containing thin crystalline substance；The described clear liquid flow export from the middle part of flash evaporation crystallizer (5) flows out and is squeezed into fine crystal elimination device (6) by fine crystal elimination pump (14) and the thin crystalline substance in a clear liquid is carried out heating for dissolving, and a clear liquid after dissolving back flows back into and forms a closed circuit in flash evaporation crystallizer (5)；
A described magma is squeezed into and is carried out thickening in thickener (7) and obtain secondary magma and secondary clear liquid by crystallizing discharging pump (15)；Secondary magma enters in centrifuge (8) and is centrifuged isolated chloride solid and centrifugal liquid, and chloride solid is discharged by the chloride solid discharging opening (26) of centrifuge (8) bottom, and centrifugal liquid enters in mother liquor tank (9)；Secondary clear liquid entrance settler (10) carries out settling clarification and obtains sedimentation liquid and potassium nitrate mother solution, and sedimentation liquid enters in mother liquor tank (9), and the potassium nitrate mother solution potassium nitrate mother liquor outlet (25) from settler (10) top flows out；
It is provided with upper and lower two fixed gases outlet in described effect heating chamber (1) to discharge for the fixed gas in effect heating chamber (1), ammonium chloride mother liquor is heated by the indirect steam entered two effects heating chamber (3) from effect separation chamber (2), fixed gas contained in two effects heating chamber (3) is discharged by the fixed gas outlet of two effect heating chamber (3) upper and lowers respectively, the condensed water that indirect steam is formed after heat exchange is discharged by two effects indirect steam condensation-water drain (19) of two effect heating chamber (3) bottoms, then uncooled indirect steam discharges from two two effects indirect steam outlet (18) imitating separation chamber (4) tops in entering two effects separation chamber (4) being connected with two effects heating chamber (3)；
Also including that one utilizes steam condensate (SC) to be arranged on last evaporator ammonium chloride mother liquor porch for preheating the preheater of the ammonium chloride mother liquor of crystallization to be evaporated, the steam condensate (SC) outlet of preheater and last evaporator is connected.
A kind of evaporative crystallisation process when producing potassium nitrate to ammonium chloride the most according to claim 1, it is characterized in that: described multi-effect evaporating device is triple effect evaporation vaporizer, ammonium chloride mother liquor enters from the top of triple effect evaporator, arrive 2nd effect evaporator, 1st effective evaporator successively, triple effect evaporator is also equipped with upper and lower two fixed gases outlet.
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| CN106277117A (en) * | 2016-08-27 | 2017-01-04 | 闫三朋 | The ammonium chloride waste-water independent low temperature double-effect evaporation method and apparatus of double adverse current |
| CN106379920B (en) * | 2016-11-17 | 2018-02-06 | 河北言明化工设备有限公司 | Lithium chloride sodium chloride mixed aqueous solution evaporation analysis sodium produces the device and method of pure lithium chloride solution |
| CN107986300B (en) * | 2018-01-19 | 2023-09-12 | 江西金利达钾业有限责任公司 | A vacuum concentration system for separating ammonium chloride in potassium nitrate production |
| CN108585089A (en) * | 2018-05-24 | 2018-09-28 | 苏州鼎昌节能环保科技有限公司 | A kind of sodium chloride ammonium chloride divides salt crystallization processes and device |
| CN108726615A (en) * | 2018-08-01 | 2018-11-02 | 江苏泰特联合环保科技有限公司 | A kind of hydrochloric acid pickling waste liquor triple effect negative pressure counter flow flash crystallization treatment technique and device |
| CN111001183A (en) * | 2019-09-09 | 2020-04-14 | 湖南中核金原新材料有限责任公司 | Double-effect continuous crystallization method of trisodium phosphate |
| CN111661853A (en) * | 2020-01-03 | 2020-09-15 | 宁夏云泰科技有限公司 | Production process of industrial ammonium chloride |
| CN111573646B (en) * | 2020-04-02 | 2021-11-30 | 江苏德邦多菱健康科技有限公司 | Preparation method of disodium hydrogen phosphate large particles by double-effect crystallization method |
| CN114455607B (en) * | 2022-03-08 | 2023-04-25 | 重庆工贸职业技术学院 | Purification method of industrial byproduct ammonium chloride |
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| CN103303942B (en) * | 2013-06-08 | 2015-04-29 | 湖北兴发化工集团股份有限公司 | Method and device for recycling ammonium chloride from glycine mother liquor |
| CN104261429B (en) * | 2014-10-10 | 2016-06-29 | 诺贝丰（中国）化学有限公司 | The continuous triple effect falling film concentration of ammonium chloride, vacuum crystallization system and method in a kind of double decomposition Production of Potassium Nitrate |
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