CN1027750C - Process and apparatus for preparing sodium bicarbonate - Google Patents

Abstract

The present invention relates to a method for preparing heavy alkali in a combined alkali method or an ammonia alkali method and a circulation carbonizing tower thereof. The present invention is characterized in that the carbonization tower separated by a plurality of reaction regions in the tower carries out carbonization by steps in the conditions of high carbonization and low magma concentration, and the heavy alkali precipitated from a raw material solution of the combined alkali method or the ammonia alkali method is taken out by steps. Ammonia absorption and cooling are carried out by steps to an unsaturated solution of the heavy alkali to remove reaction heat, and the defects brought by cooling to the heavy alkali suspension are overcome. The carbonization tower, an ammonia absorption device, a cooler, etc. can continuously work for a long term and do not need standby, and only a section of air input is needed. The absorption rate of CO2 is high, the C concentration of tail gas is low, and the present invention can produce the heavy alkali with big particle size (more than 120 mum) and good operation performance and is suitable for the production processes of the heavy alkali and similar production processes.

Description

Process and apparatus for preparing sodium bicarbonate

The invention relates to produce in the sodium bicarbonate production process of (by this speciality habit, in this specification sheets sodium bicarbonate being called for short the alkali of attaching most importance to) at solvay soda process or connection alkaline process makes carbonization supply with technological process and equipment that heavy alkali is separated out in liquid carbonization under 15-40 ℃ of temperature condition.

Traditional heavy alkali manufacture method has solvay soda process and connection alkaline process, and these methods all make carbonization supply with liquid and CO ₂Solid/liquid/gas reactions is separated out the operation of heavy alkali, all used equipment that is called Sol dimension carbonating tower (Solvay Carbonator) and the technological process of producing heavy alkali with this tower in the past, this tower structure complexity, top is a plurality of bamboo rain-hats, the bottom is provided with a plurality of cooling water tanks, removes the reaction heat of heavy alkali precipitation process to cool off heavy alkali magma; When producing heavy alkali, require that carbonization is supplied with in liquid and the tower, the temperature higher (40-65 ℃) of top reaction solution, CO with this tower ₂The assimilated efficiency of gas is low, and carbonating tower must design very highly; Because heavy alkali very easily generates the scar dirt on the water-cooled tube outer wall, must prepare two or more tower grouping operations in the production, alternately crop rotation is cleaned, and this has just increased facility investment and operation, maintenance cost; Because the cause that heavy alkali scabs on water-cooled tube makes the operation of tower become complicated especially, need regulate cooling water inflow continually and the precise dose Controlling System is arranged; Also be difficult to make the big heavy alkali particle of processing property excellent particle size with this tower.

As improvement to aforesaid method and used carbonating tower thereof, Japan clear 51-31239 of special permission and Japanese kokai publication hei 1-208315 propose a kind of carbonating tower of the A of being called formula tower and produce the method for heavy alkali with this tower under 18-40 ℃ of temperature condition, the multistage reaction zone is arranged in this tower, it between each reaction zone the infundibular body that an enlarging limit, upper end and tower body inwall fuse, reaction solution imports its hypomere reaction zone through this infundibular body from the epimere reaction zone, a upper coarse and lower fine inner circulating tube is stretched in the infundibular body lower end, one gas dispersion plate is arranged at the inner circulating tube bottom, when in the connection alkaline process, producing weight alkali with this tower, the ammonia mother liquor II of defined moves down from top to bottom piecemeal from beginning section reaction zone in the connection alkaline process, from the CO of latter end and stage casing reaction zone segmentation feeding ₂Gas disperses bubbling to move up piecemeal from top to bottom and (in this specification sheets liquid and CO is supplied with in carbonization with the reaction solution in each section reaction zone through the gas dispersion plate ₂The heavy alkali magma that solid/liquid/gas reactions generated is referred to as reaction solution) the convection current contact reacts, in each section reaction zone, reaction solution nationality density difference and gas lift act on circulation limit, outside reaction in the inner circulating tube; In order to remove the reaction heat of separating out heavy alkali and to keep the suitable alkali liquid temperature that goes out, its latter end reaction zone need be set up the water cooler cooling reaction solution of pump circulation, therefore, when in the connection alkaline process, producing sodium bicarbonate with A formula tower, water cooler still scabs easily, reduces rate of heat transfer, needs standby water cooler crop rotation and cleans, so both increase facility investment, increased maintenance load and operation easier again; Owing between latter end reaction zone and external cooler, carry out pump circulation with the pump delivery reaction solution, between the crystallization of sodium bicarbonate particle, bump will take place between particle and circulating pump impeller blade and the wall as a result and produce too much crystallization or fragment, and heavy alkali magma excessive concentration in the latter end reaction zone reaction solution, the generating capacity of secondary nucleus is still quite big, so heavy alkali particulate increases and the improvement of processing property is not remarkable, in addition, this tower structure is difficult to avoid the gas of hypomere reaction zone to scurry into the epimere reaction zone by infundibular body, be difficult to avoid the gas under the gas dispersion plate to cause the reaction solution back-mixing, make crystallization of sodium bicarbonate of poor quality towards the liquid that reacts.

When A formula tower is used in the solvay soda process when producing heavy alkali with the ammoniated brine carbonization of solvay soda process defined, because the ammoniated brine of carbonization unit volume is separated out more heavy alkali than the ammonia mother liquor II of carbonization unit volume, need remove more reaction heat, therefore, except the latter end reaction zone, also need also set up the external forced recirculation cooler at other section reaction zone, so, above-mentioned weak point is even more serious, though flat 1-208315 proposition turns back to the heavy alkali separation of part mother liquor in the ammoniated brine and recycles, to reduce the heavy alkali amount of separating out in the unit volume carbonization supply liquid, in the time of can making A formula tower be used in the solvay soda process, also can as be used in the connection alkaline process in the time need set up the external forced recirculation cooler at the latter end reaction zone; And, can suitably reduce the heavy alkali magma concentration in the latter end reaction zone reaction solution, reduce the generating capacity of secondary nucleus, but, this scheme does not solve recycle pump and smash crystallization of sodium bicarbonate particulate defective when external cooler is carried reaction solution, and, because separating mother liquor, the heavy alkali of part returns the stock liquid system, increased the treatment capacity of stock liquid, in order to absorb given CO ₂Gas need increase the volume of A formula tower, thereby has increased facility investment and power consumption, and this shortcoming has limited the amount of returning that heavy alkali separates mother liquor conversely again, has reduced implementation result; In addition, this scheme still needs to be provided with pre-carbonating tower etc.

Chinese patent CN87103005 has proposed carbonization tower cooled externally by natural circulation, when in the connection alkaline process, producing weight alkali with this tower, though overcome recycle pump in the particulate shortcoming of in the process of external cooler conveying reaction solution, smashing crystallization of sodium bicarbonate, but, because the hydronic reaction solution that contains a large amount of crystallization of sodium bicarbonate in the latter end reaction zone that remains, therefore water cooler easily scabs, and need have standby water cooler to rotate operation; Weak points such as the generation of secondary nucleus is still considerable, and the improvement of crystallization of sodium bicarbonate quality is not remarkable still exist, and, use with Sol dimension carbonating tower when producing heavy alkali and produce the identical traditional technology process of weight alkali with this tower, so the temperature of carbonization supply liquid and tower middle and upper part is still higher, CO ₂The assimilated efficiency of gas is low, and tower is higher, particularly in order to remove a large amount of reaction heat of carbonization, needs the existing shortcomings of traditional technology such as enough big frigorimeter area of design and precise dose Controlling System not overcome yet.

The common drawback of above-mentioned prior art is it all is to carry out a step carburizing reagent in a carbonating tower, promptly going into the whole heavy alkali that should separate out in accordance with regulations in the carbonization supply liquid (ammonia mother liquor II or ammoniated brine) of tower all needs all to separate out by the carburizing reagent in this tower, and by all taking out at the bottom of the tower, heavy alkali magma excessive concentration at the bottom of the tower in the reaction solution, and, in order to keep out alkali lye in suitable temperature range, all must remove a large amount of reaction heat of carbonization by the mode of cooling reaction solution (heavy alkali heavy sizing), therefore, must bring aforesaid all weak points, different is that insufficient degree has difference.

The objective of the invention is to overcome carbonizing apparatus used in the prior art and must set up the defective that reaction solution brought in the water cooler cooling carburizing reagent, in solvay soda process or in the connection alkaline process, provide a kind of need not cool off that the reaction solution in carburizing reagent just can make the method for producing heavy alkali that carburizing reagent carries out again under 15-40 ℃ and for this method use, can avoid the carbonating tower (being called C formula tower in this specification sheets) of reaction solution back-mixing between the adjacent reaction district.

The object of the invention can reach by following measure:

In the connection alkaline process, produce when weighing alkali, under 15～40 ℃, step carbonation in N tower, N=2-4, mother liquor II with defined in the connection alkaline process is that liquid is supplied with in I step (step beginning) carbonization of tower, all the other respectively go on foot tower then each with its back tower go out the filtrate of alkali lye through solid-liquid separation, after inhaling ammonia and being cooled to 15～30 ℃, be its carbonization supply liquid again, each goes on foot tower and all advances CO with one section ₂The mode of gas feeds from the tower bottom and contains CO ₂The gas of gas, end go on foot the system ammonium operation that the filtrate n of alkali lye after solid-liquid separation removes to join alkaline process that of tower, and the composition of filtrate n is equivalent to join the mother liquor I of defined in the alkaline process, and filtrate n becomes the mother liquor II and recycles for this law after producing ammonium chloride.In solvay soda process, produce when weighing alkali, then under 15～40 ℃, step carbonation in M tower, M=3-7, is that liquid is supplied with in I step (step beginning) carbonization of tower with ammonia and sodium chloride concentration (mol) than the ammoniated brine (the ammonia salts solution of in this specification sheets the secondary brine of defined in the solvay soda process being made through suction ammonia calls and contains ammoniated brine) that contains that is 0.4～0.6, all the other respectively go on foot tower, and then each goes out the filtrate of alkali lye through solid-liquid separation with its back tower, supply with liquid for its carbonization again after inhaling ammonia and being cooled to 15～30 ℃, each goes on foot tower and all advances CO with one section ₂The mode of gas feeds from the tower bottom and contains CO ₂The gas of gas, end step tower go out the filtrate m of alkali lye after solid-liquid separation, its composition is equivalent to the heavy alkaline filtration mother liquor of defined in the solvay soda process, the ammonia still process of deammoniation alkaline process, therefore, by the inventive method, other operation of connection alkaline process or solvay soda process still can be operated by the existing processes flow process.

By the inventive method, as long as distribute and respectively go on foot the heavy alkali number that to separate out in the tower, each step, the corresponding heat of reaction of inhaling the ammonia amount and need remove was also just determined, this knows those skilled in the art, be the distribution of the heavy alkali amount of separating out of set step number and each step tower to guarantee respectively to go on foot tower go out alkali lye by suitable temperature with form, guaranteeing respectively to go on foot going out of tower has the heavy alkali number of certain solid in the alkali lye, avoid in the process ammonium chloride to separate out.When the heavy alkali number of separating out when minute step number N or too much or per step of M is very few, then can increase the load that the alkali lye solid-liquid separation, otherwise what need that the lower carbonization of control supplies with liquid goes into the tower temperature, increase difficulty to cooling, and be unfavorable for producing the crystallization of sodium bicarbonate of the thick and good operation performance of particle.

By the inventive method, the gross weight alkali number that should separate out in the ammoniated brine of defined in the mother liquor II of defined or the solvay soda process in the connection alkaline process is separated out with the method for step carbonation, each carburizing reagent that goes on foot in the tower can be carried out under high degree of carbonisation and low heavy alkali magma concentration, and, each goes on foot refrigerative is to isolate the heavy alkali solution after inhaling ammonia treatment again, therefore, refrigerative is the undersaturated solution of counterweight alkali, thereby solved for a long time in soda industry production existing abominable because of cooling off the crystallization of sodium bicarbonate process condition that heavy alkali magma causes, complicated operation this technical barrier.

The used C formula tower of the inventive method is to the improvement of above-mentioned A formula tower, has CO in the tower ₂Tail gas absorber portion and multistage reaction zone respectively are equipped with inner circulating tube and gas-liquid segregation section in each section reaction zone, be provided with in latter end reaction zone bottom to contain CO ₂The gas input port of gas, this C formula tower has following feature: (1) is equipped with the distance member that separates each section reaction zone gas in the tower, liquid connection, to avoid the reaction solution back-mixing under gas percussion in each reaction zone, gas between each section reaction zone and liquid are by being installed in tower outer gas duct and reaction solution conduit UNICOM, the reaction solution that is the preceding paragraph reaction zone is supplied with liquid from flowing to adjacent next section reaction zone as the carbonization of this reaction zone by conduit, by the CO of latter end reaction zone feeding ₂Gas is then from bottom to top through being connected on the gas duct between each reaction zone, through CO ₂Discharged by cat head behind the tail gas absorber portion, (2) stretch into the CO in each reaction zone ₂Gas inlet tube end is that wide-mouth taper down enlarges mouth, to improve CO ₂The dispersity of gas, the crystallization of sodium bicarbonate particle that is deposited at the bottom of distance member or the tower has been dashed fluidisation, participate in crystallisation process, and it is successfully arranged from this reaction zone or in tower take out, (3) reaction solution and the delivery port that goes out alkali lye respectively are housed at the middle part of each section reaction zone and latter end reaction zone, to avoid being deposited on obstruction reaction solution conduit such as macrobead scar piece at the bottom of each reaction zone bottom and the tower and to go out the alkali lye output tube, (4) are at CO ₂Between tail gas absorber portion and the beginning section reaction zone catheter is housed, its exit end should stretch in the reaction solution of beginning section reaction zone, to avoid the reaction solution back-mixing, improves tail gas CO ₂Decontamination effect improving, (5) upper space of reaction solution conduit and tail gas absorber portion has communicating pipe, to discharge the gas of carrying secretly in the reaction solution, guarantee the reaction solution conduit free, (6) wide-mouth nozzle-like thing down respectively is housed in the bottom of each inner circulating tube, enlarges the CO that contains that mouth is gone into tower to collect and to compress through taper ₂Gas, it is sprayed in the inner circulating tube so that the reactant in each reaction zone increases circulation power in the inside and outside formation circulation of inner circulating tube, improve the crystallization of sodium bicarbonate process condition.

Because reaction heat of carbonization is by the sensible heat mode with supply with liquid by the undersaturated carbonization of cooling counterweight alkali and remove going into the tower reach in the inventive method, therefore, by the inventive method, the used C formula tower or the carbonating tower of other pattern do not need to set up any cooling apparatus.

The inventive method and used C formula tower thereof are for reacting between some gas, liquid, and the technological process that needs cooling to contain the resultant crystallization suspension and easily cause scabbing, same being suitable for.

Purpose of the present invention can also reach by following measure:

When the inventive method was used in the connection alkaline process, the gross weight alkali number that should separate out from used mother liquor II was 168～189g/l, and when being used in the solvay soda process, and by the about 315g/l of gross weight alkali number that should separate out in the ammoniated brine, therefore, the used branch step number of the latter is generally more; In order to simplify the operation and to be convenient to regularization to equipment such as C formula tower, ammonia absorber and water coolers, each go on foot the heavy alkali number of separating out in the C formula tower with uniformly distributing for well, be the heavy alkali amount of separating out and the ratio (weight) of supplying with the gross weight alkali number that to separate out in the liquid (mother liquor II or ammoniated brine) of per step carbonization, in the connection alkaline process is 1: N is 1 in solvay soda process: M; The heavy alkali number that per step carbonization is separated out to be to be controlled at 63～105g/l, i.e. N=2～3, M=3～5 are for well, and this is to improving the crystallization of sodium bicarbonate quality, reduces facility investment and high and stable yields all being beneficial to.

When the inventive method is used in the solvay soda process, also can except that end step tower respectively go on foot tower or certain step tower go out alkali lye in the filtrate of solid-liquid separation, add after inhaling ammonia and before the cooling and make with extra care NaCl, with raising NaCl transformation efficiency, reduce the alkali-making mother solution equivalent, reduce the energy consumption of ammonia still process.

Described C formula top of tower is provided with CO ₂The tail gas absorber portion wherein can be installed sieve plate, also can install parts such as bubble-cap or bamboo rain-hat to make full use of the CO in the tail gas ₂The supply liquid of going into tower is given carbonization, and the CO in the reclaiming clean tail gas ₂, outside tower, be provided with gas duct between this absorber portion and its underpart next-door neighbour's the beginning section reaction zone, the distance member of described C Shi Tanei can be a convex surface dome head down, also can adopt convex surface down taper or the plate-like end socket to help entering the CO of reaction zone ₂Gas has dashed fluidisation to the crystallization of sodium bicarbonate particle that is deposited to the reaction zone bottom, avoids causing accumulation.CO ₂Catheter between tail gas absorber portion and the beginning section reaction zone can be the downtake that is contained in the tower, also can be contained in outside the tower.

The inventive method and used C formula tower thereof compared with prior art have following advantage:

1. the crystallization of sodium bicarbonate quality is good, be big (median size＞120 μ m) and epigranular of particle, good operation performances such as filtration and washing, be easier to adopt whizzer to filter, its filter cake moisture content low (＜10%) can significantly reduce the energy consumption of calcination process, and provide condition for the calcining of the no accumulation of salt in the surface soil, and the quality of finished product soda ash, salt low (＜0.5%), loose density can reach 600Kg/m ³More than, have good packing and use properties.

2. water cooler does not scab substantially, does not need standby water cooler alternately operating, and can adopt high-efficiency heat exchanger equipment, and the heat transfer efficiency height can significantly be saved facility investment expense and consumption of cooling-water.

3.C formula tower volume ability (can reach 1.2t/m greatly ³.d), it is light to scab, and internal structure is simple, and working cycle, long (can reach more than six months) do not need stand-by still, and its turnover gas, liquid measure generally need not regulated when normal running, so can accomplish long-term high and stable yields.

4. produce the CO that heavy alkali is used ²Gas enters with one section intake method and respectively goes on foot C formula tower, and having overcome the need that two sections or multistage air inlet cause has shortcomings such as different sources of the gas, pipe arrangement complexity, troublesome poeration.

5. the tower height of each C formula tower lower (being lower than 20m) can reduce factory building height, saves initial cost.

6.C the turndown ratio of formula tower is big, promptly in the degree of carbonisation (130～180%) of broad, go out alkali lye magma concentration (40～110g/l) and tower unit volume ability (0.3～1.2t/m ³.d) etc. all can make the fine crystallization of sodium bicarbonate under the situation.

7. the operation and maintenance of carbonating tower, ammonia absorber and water cooler is all simple unusually, can overcome the influence that brings to production because of this class human factor that differs of operant level.

8. when being used in the solvay soda process, sodium chloride concentration in its carbonization supply liquid (containing ammoniated brine) is than high 23.4～29.3g/l of the prior art, and can in carbonization process, implement to add NaCl, and improve the NaCl transformation efficiency of carburizing reagent, reduce alkali-making mother solution equivalent and ammonia still process energy consumption.

The drawing of accompanying drawing is described as follows:

Fig. 1 is the three technological process synoptic diagram of step during carbonization.

Fig. 2 is the C formula tower diagrammatic cross-section in band second-stage reaction district.

Below in conjunction with description of drawings the present invention:

As shown in Figure 1, will import I for feeding (be mother liquor II in alkaline process at connection, in ammonia-soda process for containing ammonial brine) and go on foot C formula tower A₁Top, at A₁The bottom of tower passes into CO₂Gas 5 carries out carbonization, finishes heavy alkali precipitation process of I step, and tail gas 6 is discharged from cat head, A₁Tower go out alkali lye 1 through seperator B₁Be separated into heavy alkali 2 and filtrate 3, filtrate 3 is delivered to ammonia absorber C₁, the filtrate 4 behind the suction ammonia is delivered to cooler D₁, cooled mother liquor 7 enters II step C formula tower A₂Top with from A₂The CO that the tower bottom passes into₂Heavy alkali precipitation process of II step is finished in gas 8 reactions, and tail gas 9 is discharged from cat head, A₂Tower go out alkali lye 10 seperator B₂Be separated into heavy alkali 11 and filtrate 12, filtrate 12 is delivered to ammonia absorber C₂, the filtrate 13 behind the suction ammonia is delivered to cooler D₂, cooled mother liquor 14 enters III step C formula tower A₃Top with from A₃The CO that the tower bottom is sent into₂Heavy alkali precipitation process of III step is finished in gas 15 reactions, and tail gas 16 is discharged from cat head, A₃Tower go out alkali lye 17 through seperator F Separation of Solid and Liquid or be separated into heavy alkali 18 and filtrate 19 with seperator F after heavy alkali 2, heavy alkali 11 mix in thickener E, heavy alkali 18 send calcination process, filtrate 19 is sent ammonium operation processed (connection alkaline process) or ammonia still process (ammonia-soda process).

The carburizing reagent of C Shi Tanei is described below in conjunction with Fig. 2:

Enter the tail gas absorber portion 22 of two sections C formula towers 21 for feeding from entrance 20, enter first paragraph reaction zone 24 through downspout 23, enter second segment reaction zone 26 through reactant liquor conduit 25 again, go out alkali lye and discharge from going out alkali lye outlet 27; Contain CO₂The gas of gas enlarges mouth 28 from entrance 30 through taper, nozzle 35 enters inner circulating tube 32, utilize in the gas lift effect and inner circulating tube of gas, reactant liquor in the density contrast of outer reactant liquor and the second segment reaction zone reacts on reaction zone inner edge circulation limit, the crystallization of sodium bicarbonate particle that is deposited on the dome head 29 has also been rushed the participation reaction simultaneously, unreacted gas is by after separating cap 40 bafflings, through gas conduit 33, taper enlarges mouth 34, nozzle 35 enters inner circulating tube 36, in the first paragraph reaction zone and reactant liquor and from the crystallization of sodium bicarbonate particle of dome head 37 upper punches in inner circulating tube 36, the reaction of circulation limit, outside, the gas that separate through separation cap 41 on first paragraph reaction zone top enters the tail gas absorber portion through gas conduit 38, through having reclaimed CO₂Tail gas discharged by exhaust outlet 39; Can keep pressure in the tail gas absorber portion by the capacity of regulating exhaust outlet, communicating pipes 42 are communicated with the upper space of reactant liquor conduit 25 and tail gas absorber portion.

Be described in further detail the present invention with embodiment below:

Example 1: implement A by two step carbonizations with two sections C formula towers ₁, A ₂Tata footpath 1.6m, tower height 19.094m, tail gas absorber portion height 4.25m, 5 of interior dress bamboo rain-hats, A ₁It is 19.4 ℃, 20m that tower is supplied with liquid ³The mother liquor II of/h flow, A ₂It is A that tower is supplied with liquid ₁Tower goes out the filtrate of alkali lye through solid-liquid separation, again through inhaling ammonia and being cooled to 18.3 ℃, containing the mother liquor of free ammonia 44.2g/l, A ₁, A ₂The in parallel feeding in tower bottom contains CO ₂27.8% gas, tower top pressure 0.5gMPa, A ₁, A ₂Tower goes out 40 ℃ of alkali liquid temperatures, and it is 171g/l that heavy alkali is separated out total amount, heavy alkali median size 164 μ m, and it is spherical, cylindrical that its shape mostly is, and whizzer separates the heavy buck part 8.3% in back, salt 0.18%, tail gas contains CO ₂Be lower than 2%, tower unit volume ability is 1.2t/m ³.d.

Example 2: press Fig. 1 three step carbonizations with two sections C formula towers and implement the tower diameter 0.16m of each carbonating tower, tower height 3.5m, A ₁The supply liquid of tower be 16 ℃, 45l/h contain ammoniated brine, its component: FNH ₃47.2g/l, CNH ₃7.0g/l, Tcl175.7g/l, CO ₂33.9g/l, go into A ₂, A ₃The solution of tower is respectively A ₁, A ₂Tower go out the filtrate of alkali lye through solid-liquid separation, again through inhaling ammonia and being cooled to 16 ℃, containing FNH ₃47.6g/l mother liquor, the in parallel feeding in each tower bottom contains CO ₂85% gas, go out alkali liquid temperature and be 40 ℃, heavy alkali is the amount of separating out 330g/l always, NaCl transformation efficiency 76.0%, it is spherical, cylindrical that heavy alkali median size 127.1 its shapes of μ m mostly are, and whizzer separates the heavy buck part 6.1% in back, burns till rate 59.8%, soda ash contains NaCl0.32%, tower unit volume ability 1.0t/m ³.d.

Example 3: implement by 7 step carbonizations with two sections C formula towers, each goes on foot the tower diameter 0.16m of carbonating tower, tower height 3.5m, A ₁The supply liquid of tower be 30 ℃, the 105l/h flow contain ammoniated brine, its component: FNH ₃34.9g/l, CNH ₃7.2g/l, Tcl177.5g/l, CO ₂33.9g/l, go into A ₂～A ₇The solution of tower respectively is A ₁～A ₆Tower go out the filtrate of alkali lye through solid-liquid separation, again through inhaling ammonia and being cooled to 30 ℃, containing FNH ₃35.0g/l mother liquor, the in parallel feeding in each tower bottom contains CO ₂85% gas, each tower go out alkali liquid temperature and are 40 ℃, and heavy alkali is the amount of separating out 330g/l always, heavy alkali median size 135 μ m, tower unit volume ability 1.0t/m ³.d.

Example 4: carry out solvay soda process three step carburizing reagents by example 2, at A ₂Tower goes out alkali lye after the filtrate of solid-liquid separation is inhaled ammonia, adds the NaCl into 25g/l before cooling, and heavy alkali is the amount of separating out 365g/l always, and the NaCl transformation efficiency reaches 78.5%, heavy alkali median size 125 μ m, and it is spherical and cylindrical that its shape mostly is, tower unit volume ability 1.0t/m ³.d.

Claims (8)

1, produce the method for sodium bicarbonate in the connection alkaline process, carry out carburizing reagent with carbonating tower under 15～40 ℃ of temperature condition, feature of the present invention is at N C Shi Tanei, N=2-4, and each tower advances CO with one section ₂The mode step carbonation of gas, with the mother liquor II is that liquid is supplied with in the carbonization of tower of I step, all the other respectively go on foot tower each with its back tower go out the filtrate of alkali lye through solid-liquid separation, after inhaling ammonia and being cooled to 15～30 ℃, supply with liquid again for its carbonization, the alkali lye that goes out that the end goes on foot tower goes to make the ammonium operation through the filtrate n of solid-liquid separation.

2, in accordance with the method for claim 1, the ratio (weight) of the total carbonic acid hydrogen sodium that should separate out in the mother liquor II of the sodium bicarbonate amount of separating out that it is characterized in that per step carbonization and connection alkaline process defined is 1: N, N=2-3.

3, produce the method for sodium bicarbonate in solvay soda process, carry out carburizing reagent with carbonating tower under 15～40 ℃ of temperature condition, feature of the present invention is at M C Shi Tanei, M=3-7, and each tower advances CO with one section ₂The mode step carbonation of gas, is that liquid is supplied with in the carbonization of tower of I step with ammonia and sodium chloride concentration (mol) than the ammoniated brine that contains that is 0.4～0.6, all the other respectively go on foot tower, and each goes out the filtrate of alkali lye through solid-liquid separation with its back tower, supply with liquid for its carbonization again after inhaling ammonia and being cooled to 15-30 ℃, the end step alkali lye that goes out of tower removes ammonia still process through the filtrate m of solid-liquid separation.

4, in accordance with the method for claim 3, the ratio (weight) of the total carbonic acid hydrogen sodium amount that should separate out in the ammoniated brine of the sodium bicarbonate amount of separating out that it is characterized in that per step carbonization and solvay soda process defined is 1: M, M=3-5.

5, according to claim 3 or 4 described methods, it is characterized in that except that end step tower respectively go on foot tower or certain step tower go out the filtrate of alkali lye through solid-liquid separation, NaCl is made with extra care in adding after inhaling ammonia and before the cooling.

6, according to the used carbonating tower of the method for claim 1 or 3, has CO in the tower ₂Tail gas absorber portion and multistage reaction zone respectively are equipped with inner circulating tube and gas-liquid segregation section in each section reaction zone, be provided with in latter end reaction zone bottom to contain CO ₂Gas input port, feature of the present invention is: (1) is equipped with and is separated the distance piece that gas in each section reaction zone, liquid are communicated with, and has between each section reaction zone to be located at tower outer gas duct and reaction solution conduit, and (2) stretch into the CO in each section reaction zone ₂Gas inlet tube end is that wide-mouth taper down enlarges mouth, and (3) respectively are equipped with reaction solution at the middle part of each section reaction zone middle part and latter end reaction zone and are gone out the delivery port of alkali lye, and (4) are at CO ₂Between tail gas absorber portion and the beginning section reaction zone catheter is housed, its exit end stretches in the reaction solution of beginning section reaction zone, (5) reaction solution conduit and tail gas absorber portion upper space have communicating pipe, and (6) respectively are equipped with wide-mouth nozzle-like thing down in the bottom of each inner circulating tube.

7,, it is characterized in that described catheter is the downtake that is installed in the tower according to the described tower of claim 6.

8,, it is characterized in that described distance piece is a convex surface dome head down according to the described tower of claim 6.

Images