CN209507611U - Chlor-alkali salt water primary purification system - Google Patents

Abstract

The utility model discloses a kind of chlor-alkali salt water primary purification systems, including mixing channel, first reactor and rear reaction system；Second reactor is provided between first reactor and rear reaction system, the second reactor is provided with brine outlet, and the salt water in second reactor can be by forcing outer circulation pump to return in first reactor through brine outlet；The bottom of the first reactor and second reactor is equipped with salt slurry outlet, and the salt slurry generated in reaction process can be exported by salt slurry enters salt slurry circulatory pool, then returns to mixing channel through salt slurry circulating pump.The utility model has the advantages that: 1) silica removal rate can reach 30~70%；2) reagent is added without additional using the system refined brine, new other foreign ions will not be introduced；3) processing cost is low, only need to disposably put into equipment component, has realistic feasibility.

Description

Chlor-alkali salt water primary purification system

Technical field

The utility model relates to a kind of chlor-alkali production equipment, especially a kind of ionic membrane method alkali-chloride equipment.

Background technique

Industrial electricity consumption solution is saturated the method for NaCl solution to produce NaOH, Cl₂And H₂, and using them as raw material production one The industry of series chemical product, referred to as chlorine industry.Production of caustic soda technique in the world's mainly has ionic membrane method, diaphragm process and water at present Silver-colored method separately has a small amount of causticizing process.Wherein low energy consumption, product purity is high, pollution is small, operating cost is low for ionic membrane method, is newly-built burning The first choice of alkali device.

Chlor-alkali production technique mainly includes salt refining process and electrowinning process, and wherein brine rectification process is referred to containing The crude brine of NaCl is handled to remove the process of wherein impurity.The raw material for preparing NaCl crude brine is mainly crude salt, according to Source is different, and crude salt can be mainly divided into sea salt, well salt, lake salt, four major class of rock salt.But crude salt price is higher, to improve enterprise Economic benefit, current each enterprise, which is widely used, substitutes part or all of crude salt alkaline with brine.But due to brine impurity content It is larger, new problem is undoubtedly proposed to chlor-alkali production technique.

Such as my company's chlor-alkali plant uses and mixes halogen alkali-making process, it is 32% that maximum, which mixes halogen ratio, dissipates salt and uses vacuum salt production, halogen Water then uses well salt.Brine is to be injected made from deep-well salt dissolving with industry water, therefore silica is very high always in brine.Quality inspection Analysis data show that silica average content is 7.95mg/L in brine, and up to 15.8mg/L, average value is more than index value (index is≤5.0mg/).

Current brine rectification process can be divided into salt water primary purification and salt water secondary refining.Salt water primary purification is to use Chemical refining agent (NaOH and Na is added₂CO₃) by soluble impurity in salt water insoluble,practically sediment is converted, then pass through The means such as clarification, filtering achieve the purpose that purification.It is mainly comprised the steps that

A, crude brine is made using crude salt or/and brine as raw material；

B, NaOH and Na is added into crude brine₂CO₃Obtain mixed salt water；

C, mixed salt water obtains primary purification salt water and salt slurry through being separated by solid-liquid separation, and primary purification salt water enters secondary refining work Sequence, salt slurry are handled or are utilized.

Salt water secondary refining mainly uses chelate resin tower to remove the Ca in demineralized water²⁺And Mg²⁺To reach the mesh of purification 's.Up-to-standard secondary refining salt after resin tower processing, can supply electrolysis workshop section on demand.

In electrolytic process, since salt water is closed cycle, silica is can not to remove during current salt refining Go, thus silica can in brine system gradually accumulation increase, excessive silica can in salt water calcium, strontium, Barium, aluminium plasma are combined on ionic membrane or pole piece that colloid complex is attached in ion-exchange membrane electrolyzer, block film and pole piece, To cause the rise of ionic membrane current efficiency decline and electrolytic bath voltage, operating cost is made to sharp rise, it is raw to influence enterprise Produce operating cost.

Currently, removing silica method in recirculated water preparation process mainly has lime softening method, anion exchange resin Method, silica gel adsorption, reverse osmosis, electrocoagulation, microfoam flotation are except silicon etc., but these methods are mainly used for circulating water treatment and pure water Process field may cause using lime softening method etc. introduce more impurity by force since the liquid environment that equipment is applicable in is different And foreign ion, or processing cost or equipment investment cost are greatly improved, so being unsuitable for the very high salt of chloride ion content Water subtractive process.

Utility model content

It is difficult to the technical problem removed or processing cost is excessively high to solve silica in prior art salt water, inventor mentions A kind of method for having supplied in ionic membrane method alkali-chloride technique to reduce silica in salt water, comprising the following steps:

A, crude brine is made；

B, NaOH and Na is added into crude brine₂CO₃, there are Nano-meter CaCO3s in the crude brine₃, it is adequately mixed, makes thick Silica and Nano-meter CaCO3 in salt water₃Sufficiently collision absorption generates silicon condensation product, obtains mixed salt water；The nanometer calcium carbonate accounts for The mass percent of crude brine is not less than 1.1%, and collision adsorption time is no less than 0.5h；

C, mixed salt water obtains primary purification salt water and salt slurry through being separated by solid-liquid separation, and primary purification salt water enters secondary refining process It is handled.

Inventor has found in production, though current brine rectification process cannot be removed effectively the titanium dioxide in crude brine Silicon, but still there is lesser degree of removal effect to silica, being mainly reflected in can examine from the salt slurry of separation of solid and liquid The silicone content measured is higher than silicone content theoretical value contained by crude brine.Inventor speculates that its reason may be in high sodium chloride content Salt water in the silicate of solubilised state and the silica agglomerate of colloidal attitude, therefore the silica in crude brine mainly with glue Posture exists.Silica colloidal attitude and ionic state in common water body are all dynamic equilibrium, and the water bodys such as relative cycle water, Ion concentration is higher under crude salt water environment, that is, saturated sodium chloride solution state, thus it is speculated that between dioxide/silica gel posture and ionic state more It is not easy to reach balance, because single anion and the hydrone medium of single cation extremely neighbour are obviously in ionization state. When there are when granularity nanometer calcium carbonate tiny enough, just capable of by colloidal attitude silica and calcium carbonate collision in crude brine So that nanometer calcium carbonate is adsorbed on silicon dioxide colloid surface, the calcium carbonate granule of larger particles then can with deposited in silicon dioxide colloid A small amount of silica crystals particle collide with each other after formed lattice insertion mixed crystal, this mixed crystal can be with carbon The reunion and growth of sour calcium crystal, " absorption " are fallen among the scattered heap particle and crystal agglomerate of silica crystals filling calcium carbonate. If speculating that (nanometer calcium carbonate accounts for the mass percent of crude brine not there are enough nanometer calcium carbonates in saturated brine system Less than 1.1%), under stirring through the stop and collision of (more than 0.5h) for a long time enough, colloidal silicon dioxide can be made It is wrapped up completely by Nano particles of calcium carbonate, forms a kind of class sediment of condensed state, and can be filtered by filter plant.According to The invention people proposes the embodiment of the utility model.Solid-liquid separating method can be used in the mixed salt as made from this programme Except the part of silica in crude salt obtains primary purification salt water, primary purification salt water enters secondary refining process according to this field Usual processing method, which carries out processing, can be obtained secondary refining salt, and secondary refining salt can supply electrolysis workshop section on demand to be made With.Since dioxide-containing silica is substantially reduced in secondary refining salt, the electrolysis installation cycle of operation is extended, life is improved It produces efficiency and reduces operating cost.

In the present solution, nanometer calcium carbonate present in crude brine can be external addition, such as outsourcing nanometer calcium carbonate System is added in reagent, but nanometer calcium carbonate reagent price is high, is that reduction using the purpose of brine itself in view of this field Chloralkali process cost will be so that program itself if the reagent for therefore needing a large amount of buying prices high fills up its defect Meaning is lost, while additional calcium carbonate may be introduced into other impurities solution particle and can cause to chelate in secondary brine rectification process Resin tower handles load and increases.Due to can inherently generate calcium carbonate, Ca in crude brine in primary purification process²⁺With the examination of addition Agent Na₂CO₃There are no enough digestion times to grow up for the nascent calcium carbonate crystal of reaction, mainly with Nano-meter CaCO3₃Form deposit , and the Ca usually in crude brine²⁺Concentration reaches 0.15~0.35mg/L, and the nascent calcium carbonate of generation can account for the quality of crude brine The 0.4~0.6% of percentage, if it is possible to the nascent calcium carbonate in this part be made full use of, then do not needed again outside outer be added Carry out nano-calcium carbonate calcon, inventors herein propose further processing scheme accordingly: Ca in crude brine²⁺With Na₂CO₃Reaction generates Nascent CaCO₃Afterwards, nascent CaCO will be contained₃Salt water and contain nascent CaCO₃Salt slurry by circulating pump return be added to Reciprocation cycle in crude brine can so make the nascent CaCO in crude brine₃Content enrichment be increased to the 1.1% of crude salt water quality with On, and nascent CaCO therein is made by circulation stirring effect₃Particle is well dispersed in salt water, realizes titanium dioxide in crude brine Silicon and Nano-meter CaCO3₃Sufficiently collision absorption generates silicon condensation product.

To be easy to implement above scheme, inventor has also been devised a kind of chlor-alkali salt water primary purification system, including mixing channel, First reactor and rear reaction system；It is provided with second reactor between first reactor and rear reaction system, described second Reactor is provided with brine outlet, and the salt water in second reactor can be by forcing outer circulation pump to return to first instead through brine outlet It answers in device；The bottom of the first reactor and second reactor is equipped with salt slurry outlet, and the salt slurry generated in reaction process can Enter salt slurry circulatory pool by salt slurry outlet, then returns to mixing channel through salt slurry circulating pump.

Ca when reaction starts, in crude brine²⁺With Na₂CO₃It reacts in the first reactor first, salt water is gradually after reaction Enter second reactor by process pipe, reaction is basically completed at this time, generates largely nascent calcium carbonate, part calcium carbonate It is deposited on the bottom of two reactors, and salt slurry circulatory pool, the undeposited nascent carbon of another part are entered by outlet at bottom Sour calcium enters second reactor with salt water, in the second reactor by forcing outer circulation pump to send newborn calcium carbonate granule again It returns in first reactor, and being sufficiently stirred by big flow is dispersed in calcium carbonate microparticle in saline solution.In addition, into The calcium carbonate microparticle for entering salt slurry circulatory pool constantly sends it back to mixing channel with salt slurry circulating pump immediately (attention prevents salt slurry circulatory pool Emptying), and force outer circulation pump caused by realize fully dispersed under big flow disturbance, nascent calcium carbonate granule is realized with this Make full use of.Above-mentioned circulation is realized by setting second reactor, forced circulation system, the salt slurry circulatory system, stirring, is coagulated Poly-, recombination process, extends the stop and collision time of silica and nascent calcium carbonate, by crude salt water part silica It absorbs with salt slurry together by being discharged in solid waste, reduces the content of silica in crude brine, salt water is enable to accord with Ionic membrane alkaline is closed to the index request of silica in refined brine.

Stirring ratio (the stream of the pressure outer circulation for forcing outer circulation pump as a further improvement of the utility model, Measure ratio) it is 5:1~3:1.To realize sufficiently backflowing for the salt water containing nascent calcium carbonate microparticle, realize to nascent calcium carbonate microparticle It makes full use of, is formed simultaneously the circulation stirring of big flow, promote the salt water of reflux and salt slurry fully dispersed in the first reactor.

The first reactor and second reactor are that the drum with cone bottom is anti-as a further improvement of the utility model, Answer device.Enough crash response residence times are mainly provided, and guarantee that enough settling areas enable calcium carbonate granule Part reaches enrichment, recycles convenient for salt slurry.

More preferably, the process pipe for connecting each equipment is all made of isothermal holding, is stablized with maintaining reaction temperature.

The beneficial effects of the utility model are: 1) can partially remove brine in salt refining environment using set of device In the silica brought into, experiment shows that silica removal rate can reach 30~70%, by the silica in refined brine Content is maintained at qualified level；2) reagent is added without additional using the system refined brine, except salt during silica Water system will not introduce new other foreign ions；3) processing cost is low, only need to disposably put into equipment component, has reality can Row.

Detailed description of the invention

Fig. 1 is the chlor-alkali salt water primary purification system structure diagram of the utility model.

In the figure, it is marked as 1- first reactor, 2- second reactor, 3- baffling slot, 4- post-reactor, 5- force (forcing) pump, 6- Salt dredge pump, 7- salt mud sump, 8- force outer circulation pump, 9- salt slurry circulatory pool, 10- salt slurry circulating pump, 11- mixing channel.

Specific embodiment

The present invention will be further described with reference to the accompanying drawings and examples.

As shown in Figure 1, the chlor-alkali salt water primary purification system of the utility model, including mixing channel 11,1 and of first reactor Reaction system afterwards；Second reactor 2 is provided between first reactor 1 and rear reaction system, the second reactor 2 is arranged There is brine outlet, the salt water in second reactor 2 can be by forcing outer circulation pump 8 to return in first reactor 1 through brine outlet； The bottom of the first reactor 1 and second reactor 2 is equipped with salt slurry outlet, and the salt slurry generated in reaction process can pass through salt Mud outlet enters salt slurry circulatory pool 9, then returns to mixing channel 11 through salt slurry circulating pump 10.The first reactor 1 and the second reaction Device 2 is the drum reactor with cone bottom.The process pipe for connecting each equipment is all made of isothermal holding.Reaction system includes after described Baffling slot 3 as shown in Figure 1, post-reactor 4, salt mud sump 7, force (forcing) pump 5, salt dredge pump 6.

Embodiment one:

Above equipment is used for the primary purification processing of crude brine, concrete scheme to be as follows:

When work, crude brine (dioxide-containing silica 6.75mg/L, Ca²⁺Content is 0.15mg/L, Mg²⁺Content is 0.01mg/L) with metering Na₂CO₃Enter first reactor 1, the Ca in crude brine after mixing with NaOH reagent²⁺With Na₂CO₃First It is reacted in first reactor 1, salt water has stepped through process pipe and enters second reactor 2 after reaction, reacts at this time substantially It completes, generates largely nascent calcium carbonate, part calcium carbonate is deposited on the bottom of two reactors, and enters by outlet at bottom To salt slurry circulatory pool 9, the undeposited nascent calcium carbonate of another part enters second reactor 2 with salt water, in second reactor 2 It is described that outer circulation is forced to pump 8 by forcing outer circulation pump 8 to send back to newborn calcium carbonate granule in first reactor 1 again The stirring ratio for forcing external circulation stirring is 3:1, and being sufficiently stirred by big flow is dispersed in calcium carbonate microparticle in saline solution. In addition, the calcium carbonate microparticle into salt slurry circulatory pool constantly sends it back to mixing channel 11 with salt slurry circulating pump 10 immediately, and strong The lower realization of big flow disturbance caused by outer circulation pump 8 processed is fully dispersed, realizes nascent calcium carbonate granule in the first reaction with this Sufficiently collide in device 1 with the silica in crude brine absorption, and the nanometer calcium carbonate measured in first reactor 1 accounts for crude salt The mass percent of water is 1.1%, and the crash response residence time is 40min, and the crude brine for completing absorption is pushed up from second reactor 2 Portion's outflow flows into post-reactor 4 through baffling slot 3, and the timing of 4 bottom of post-reactor will contain the sediments such as calcium carbonate, silicon condensation product Salt mud emission is sent to filter press filtering to salt mud sump 7, with salt dredge pump 6.Crude brine uses high-pressure pump after flowing out in the middle part of post-reactor 4 5 be sent to HVMTM membrane filter filtering after obtain primary purification salt water, primary purification salt water enters back into secondary refining process and is handled. Measuring dioxide-containing silica in primary purification salt water is 4.67mg/L.

Embodiment two:

Above equipment is used for the primary purification processing of crude brine, concrete scheme to be as follows:

When work, crude brine (dioxide-containing silica 8.35mg/L, Ca²⁺Content is 0.24mg/L, Mg²⁺Content is 0.01mg/L and metering Na₂CO₃Enter first reactor 1, the Ca in crude brine after mixing with NaOH reagent²⁺With Na₂CO₃First It is reacted in first reactor 1, salt water has stepped through process pipe and enters second reactor 2 after reaction, reacts at this time substantially It completes, generates largely nascent calcium carbonate, part calcium carbonate is deposited on the bottom of two reactors, and enters by outlet at bottom To salt slurry circulatory pool 9, the undeposited nascent calcium carbonate of another part enters second reactor 2 with salt water, in second reactor 2 It is described that outer circulation is forced to pump 8 by forcing outer circulation pump 8 to send back to newborn calcium carbonate granule in first reactor 1 again The stirring ratio for forcing external circulation stirring is 4:1, and being sufficiently stirred by big flow is dispersed in calcium carbonate microparticle in saline solution. In addition, the calcium carbonate microparticle into salt slurry circulatory pool constantly sends it back to mixing channel 11 with salt slurry circulating pump 10 immediately, and strong The lower realization of big flow disturbance caused by outer circulation pump 8 processed is fully dispersed, realizes nascent calcium carbonate granule in the first reaction with this Sufficiently collide in device 1 with the silica in crude brine absorption, and the nanometer calcium carbonate measured in first reactor 1 accounts for crude salt The mass percent of water is 1.8%, and the crash response residence time is 1h, completes the crude brine of absorption at the top of second reactor 2 Outflow flows into post-reactor 4 through baffling slot 3, and 4 bottom of post-reactor is periodically by the salt containing sediments such as calcium carbonate, silicon condensation products Mud is discharged into salt mud sump 7, is sent to filter press filtering with salt dredge pump 6.Crude brine uses high-pressure pump 5 after flowing out in the middle part of post-reactor 4 Primary purification salt water is obtained after being sent to HVMTM membrane filter filtering, primary purification salt water enters back into secondary refining process and handled. Measuring dioxide-containing silica in primary purification salt water is 3.86mg/L.

Embodiment three:

Above equipment is used for the primary purification processing of crude brine, concrete scheme to be as follows:

When work, crude brine (dioxide-containing silica 10.10mg/L, Ca²⁺Content is 0.22mg/L, Mg²⁺Content is 0.01mg/L) with metering Na₂CO₃Enter first reactor 1, the Ca in crude brine after mixing with NaOH reagent²⁺With Na₂CO₃First It is reacted in first reactor 1, salt water has stepped through process pipe and enters second reactor 2 after reaction, reacts at this time substantially It completes, generates largely nascent calcium carbonate, part calcium carbonate is deposited on the bottom of two reactors, and enters by outlet at bottom To salt slurry circulatory pool 9, the undeposited nascent calcium carbonate of another part enters second reactor 2 with salt water, in second reactor 2 It is described that outer circulation is forced to pump 8 by forcing outer circulation pump 8 to send back to newborn calcium carbonate granule in first reactor 1 again The stirring ratio for forcing external circulation stirring is 5:1, and being sufficiently stirred by big flow is dispersed in calcium carbonate microparticle in saline solution. In addition, the calcium carbonate microparticle into salt slurry circulatory pool constantly sends it back to mixing channel 11 with salt slurry circulating pump 10 immediately, and strong The lower realization of big flow disturbance caused by outer circulation pump 8 processed is fully dispersed, realizes nascent calcium carbonate granule in the first reaction with this Sufficiently collide in device 1 with the silica in crude brine absorption, and the nanometer calcium carbonate measured in first reactor 1 accounts for crude salt The mass percent of water is 1.3%, and the crash response residence time is 2h, completes the crude brine of absorption at the top of second reactor 2 Outflow flows into post-reactor 4 through baffling slot 3, and 4 bottom of post-reactor is periodically by the salt containing sediments such as calcium carbonate, silicon condensation products Mud is discharged into salt mud sump 7, is sent to filter press filtering with salt dredge pump 6.Crude brine uses high-pressure pump 5 after flowing out in the middle part of post-reactor 4 Primary purification salt water is obtained after being sent to HVMTM membrane filter filtering, primary purification salt water enters back into secondary refining process and handled. Measuring dioxide-containing silica in primary purification salt water is 4.14mg/L.

Claims (4)

1. chlor-alkali salt water primary purification system, including mixing channel (11), first reactor (1) and rear reaction system；Its feature exists In: it is provided between first reactor (1) and rear reaction system second reactor (2), the second reactor (2) is provided with Brine outlet, the salt water in second reactor (2) can be by forcing outer circulation pump (8) return to first reactor through brine outlet (1) in；The bottom of the first reactor (1) and second reactor (2) is equipped with salt slurry outlet, the salt generated in reaction process Mud can be exported by salt slurry enters salt slurry circulatory pool (9), then returns to mixing channel (11) through salt slurry circulating pump (10).

2. chlor-alkali salt water primary purification system according to claim 1, it is characterised in that: the pressure outer circulation pumps (8) Pressure external circulation stirring stirring ratio be 5:1~3:1.

3. chlor-alkali salt water primary purification system according to claim 1, it is characterised in that: the first reactor (1) and Second reactor (2) is the drum reactor with cone bottom.

4. chlor-alkali salt water primary purification system described in any claim according to claim 1~3, it is characterised in that: even The process pipe for connecing each equipment is all made of isothermal holding.