JPS60215520A - Novel dry carbonic acid saturation - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a method for producing an alkali metal salt or ammonium hydrogen carbonate by a dry carbonation saturation method.
There is a method in which an aqueous solution of 9 cum is saturated with carbonate (r11 carbonation) to precipitate crystals of sodium bicarbonate. but,
This method takes a long reaction time, requires several steps, requires separation equipment, and requires handling a large amount of liquid.

U.S. Patent Nos. 2'76,990 and 5'74,0
No. 89 discloses a method for carbonating sodium carbonate hydrate with carbon dioxide gas in the presence of steam;
904- No. 904- states that fine jets of water on salts II't IIC↓
It is stated that air mixture can be added. However, none of these methods discloses how to adjust the reaction temperature.
Heat from an exothermic reaction is simply reaction 81! ! It just misses through the wall. The reaction times in both patents are on the order of 5-6 hours.

U.S. Pat. No. 3.64'F, 363 discloses a two-step process for making sodium bicarbonate, in which a hydrated salt of sodium bicarbonate is formed, and then the hydrated salt is Although it is carbonated, the water required for the carbonation reaction is supplied by the water of hydration liberated during the reaction. This process is slow and requires over 1 hour for carbonation and 8 hours for drying.

The product obtained in this way has a low density.

U.S. Patent No. 3. A similar two-step process is disclosed in No. FO' saturated. U.S. Patent No. 4115,52
No. 5 teaches the production of salt by heating sodium carbonate in the presence of carbon dioxide and water vapor.

The object of the invention is to provide a new dry carbonation process which avoids the problem of solution carbonation and leads to particulate alkali metal carbonate and/or ammonium carbonate to the corresponding alkali metal bicarbonate and/or ammonium bicarbonate. It is. Still another object of this invention is to provide a process for rapidly producing commercially desirable, apparently dense bicarbonate salts and suitable for a wide range of starting materials. Still another object is to provide novel deuterate-subacid composite particles having various ratios of deuterate salt and carbonate.

Other objects and advantages of the invention will become apparent from the following detailed description.

The novel method of producing granular alkali metal and/or ammonium bicarbonate of the present invention comprises, in solid phase, granular alkali metal and/or ammonium carbonate containing 2 to 50% added liquid water and granular alkali metal and/or ammonium bicarbonate based on the weight of the starting material. The raw materials are heated to about 125°F to 240°C in an atmosphere rich in carbon dioxide.
°C to 135 °C) for a time sufficient to convert at least a portion of the carbonate to the corresponding bicarbonate. The reaction conditions are adjusted to directly produce bicarbonate rather than carbonate hydrate.

The carbonate raw materials of this invention include anhydrous sodium carbonate or soda ash, potassium carbonate, ammonium carbonate, or sodium carbonate monohydrate, sodium sekis carbonate, guage shaigu bottle, anhydrous sodium bicarbonate (Ha, (:O
, *Na, HCO, *2H, O) or mixtures thereof. The raw materials used may be pure crystals or industrial grade, mixtures of non-carbonated raw materials such as common salt and carbonates.

The addition of liquid water rather makes the conditioning process rich in carbon dioxide so that the formation of bicarbonate proceeds in the carbonation reaction and thereby effectively inhibits the formation of stable carbonate hydrates. It takes place in an atmosphere of Preferably, the amount of liquid water added is relatively small,69 and multiple spray nozzles or other means are used to ensure uniform addition of water to the carbonate grains. .

The amount of liquid water added will vary depending on the type of carbonate-containing feedstock used and the degree of carbonation or the ratio of carbonate to 1L subacid to be converted. For example, to completely convert anhydrous sodium carbonate to sodium bicarbonate, from about 2096% to about 50% liquid water based on the weight of sodium carbonate should be added. However, when converting half of the anhydrous sodium carbonate-containing raw material to 9 cum of hydrogen carbonate, it is sufficient to add about 10% to about 25% liquid water based on the weight of the raw material. To completely convert sodium carbonate hydrate to sodium bicarbonate, about 7% to about 30% liquid water should be added based on the weight of sodium carbonate hydrate, converting sodium sekis carbonate to sodium bicarbonate. For complete conversion to sodium hydrogen, about 2% to about 4% liquid water should be added, based on the weight of the sodium chloride. The amount of water required for the carbonation reaction will remain in the reactor.

A certain amount of the carbonate will be reduced from unreacted carbonate as it is consumed in the formation of salt. The amount of water specified in the column is given on the basis that the water vapor in the reaction atmosphere is continuously concentrated and recycled into the reaction trough. For more details, refer to the embodiments described below. If the water vapor is not recycled, it is necessary to add an amount of liquid water to the reactor corresponding to the amount of water vapor removed.

The addition of water lasts a substantial portion of the total reaction time, e.g.
Preferably, it is carried out continuously for 15 to 25 minutes for a total reaction time of minutes. During the iETMA water addition time, sodium carbonate is added to moderate the rate of heat released by particle coagulation, caking, and carbonation reactions, and to ensure complete and uniform liquid-liquid contact. It will be determined by the properties of the particles.

The water added to the reaction may be pure water or city water, or may be an aqueous solution (aqueous solution) of sodium carbonate, sodium bicarbonate, or sodium hydroxide. It is useful to recirculate the water from the condensation of the reaction vapors and the water used to wash the caked material in the washing cycle μ.

The carbonation saturation reaction, for example with respect to sodium carbonate, proceeds according to the following reaction formula.

Na,,Cos+co,+FT,O→2 NaHCO
3+ Thermal reaction is a slight exothermic reaction, and at high temperatures sodium bicarbonate thermally decomposes to sodium carbonate, so special means of heat removal is required to prevent the temperature of the granular mass from rising too high. do. In the method of this invention, temperature is controlled by providing conditions in which heat is removed from the reaction site by evaporation of liquid water. By adding liquid water rather than steam and maintaining the water vapor in the reactor atmosphere at a reduced partial pressure, water not used as a reactant is allowed to evaporate at the reaction site, and this evaporation causes the reaction to occur. Helps to effectively remove from particles. Removing water vapor from the reactor atmosphere also helps maintain a sufficiently high partial pressure of the zero degree acid gas in the reactor atmosphere to maximize reaction rates. In this way, the added liquid water is effectively used like a heat pump, removing the heat of reaction from the particles and releasing this heat from the reactor itself.

In a preferred embodiment of the invention, liquid water is added and cooled to continuously remove some of the reaction atmosphere from the reactor and concentrate the water therein. The relatively dry atmosphere and retentate are then returned to the reactor. By adjusting the rate of vapor removal and recirculation and the temperature of the recirculating atmosphere, the reaction temperature is controlled.

In order to give priority to the production of stable carbonic acid (IJ) hydrate and the carbonation saturation reaction, 14 steps of temperature and pressure are carried out. The temperature of the granular mass (raw material), as distinguished from the reaction zone temperature, is between 5 and 240° IJ, preferably 1
60-200°F. The residence time may vary between 5 and 60 minutes. This will vary depending on the desired degree of carbonation, the raw materials used, and the reaction conditions.

80-40 minutes is preferred for complete carbonation.

The granular mass requires thorough mixing so that the water and solids are in uniform and thorough contact with the carbon dioxide, preferably using a suitable mixer in either a batch or continuous process. . 11- To prevent particle coagulation and caking and achieve more complete carbonation,
The partially carbonated product can be recycled to the feed system. The reaction wall may also be heated to prevent particle caking, with a wall temperature of 150-260°F, preferably 2.
A range of 12 to 240°l has been found to be useful. This differs from the prior art approach of cooling the reactor walls to control the reaction temperature.

The atmosphere in the reaction zone is preferably carbon dioxide and water vapor, but inert gases may also be present. The partial pressure of the podium dioxide in the reaction zone ranges from 0.2 to 0.9, preferably from 0.4 to 0.7 at a total pressure of 1 atmosphere. When the total pressure is 1 atm or more, the balance between water vapor and inert gas is maintained in proportion to this, resulting in a higher partial pressure of carbon dioxide. In a preferred embodiment of the invention, a small amount of carbon dioxide, either by atmospheric recirculation or freshly used, is introduced into the reactor through a water spray nozzle lv'ft which sprays liquid water. Ru.

The method of this invention consists of hydration and selective acid saturation f, two stages and 1 ll of rows.
- It is superior to the known method; the reaction time is longer, the carbonation saturation is higher, and excellent products are obtained. For example, in U.S. Pat. No. 3.64'1,365, sodium bicarbonate is produced in the form of hollow beads with an apparent bulk density of 20-45 bonds/ft3, which during handling It is brittle and becomes microscopic. On the other hand, the particles produced by the method of this invention are solids having a high apparent bulk density, such as 50-60 pounds per cubic foot. High-density sodium bicarbonate is in higher demand than low-density ones, primarily because shipping costs are based on weight rather than weight.

Moreover, the method of the present invention can be applied to various raw materials with only a slight variation in the method buff meter, and the particle size of the raw materials can range from fine (~100 mesh:L) to coarse. .

The process of the present invention is advantageous over prior art solution carbonation processes because it eliminates the steps and equipment necessary to separate sodium hydroxide gold from the mother liquor.

Moreover, only about 10 to 20% of the amount of water required in the solution method is required, and the operation of a solution circulation system can be omitted. In the method of the invention, a solution of sodium carbonate and crystallization of sodium bicarbonate are added to a dilute solution of sodium carbonate (10
~20% solids by weight) rather than on each individual particle, and the reaction time is 20% compared to 1-2 hours for the solution method.
-On the order of 45 minutes.

The present invention partially carbonates soda ash or sodium carbonate particles to produce discrete composite sodium bicarbonate particles having desirable properties compared to a simple mixture of sodium bicarbonate and sodium carbonate in the same proportions as in composite particles of sodium bicarbonate and sodium carbonate. It is particularly useful for The composite of this invention has a coarse particle size distribution, is more free-flowing, easier to handle, has less sedimentation of fines, and absorbs surfactants well when used as a builder in detergents. indicate a property.

In order to produce bisubate-subacid composite particles with partial carbonation of such raw materials, the amount of water added can be reduced compared to a complete conversion that produces substantially only bicarbonate particles; The amount is reduced in proportion to the bicarbonate of the final product particles.

Alternatively, the reactor atmosphere rich in carbon dioxide may be replaced with a substantially carbon dioxide-free atmosphere during the carbonation reaction to produce the partially carbonated product. In this method, most of the excess water is absorbed as hydrate, eliminating the need for drying the product.

The method of this invention is also useful for carbonation of sodium carbonate builders during the manufacture of detergents; detergent compositions containing sodium carbonate can be carbonated by the method of this invention, and the resulting compositions are It absorbs surfactants such as sulfonates and exhibits good properties.

The novel dry carbonation device of this invention includes a reaction zone, a means for introducing raw carbonate particles into the entire reaction zone, a means for introducing carbon dioxide gas into the reaction zone, and a means for uniformly introducing water into the reaction zone. , means for removing atmosphere from the reaction zone to control reaction rates and temperatures, and means for removing carbonation products from the reaction zone.

The reactor is preferably a heavy equipment for processing solids with internal stirring or a drum that is rotated or vibrated externally, whereby the reaction can be carried out batchwise or continuously. The walls of the reaction zone have jackets to heat the interior surfaces of the reactor, thereby preventing or reducing product caking at the walls. Wall temperature t-150~240°
To maintain the temperature at F, it is effective to use steam or hot water in the jacket.

The reaction zone can also be operated at superatmospheric pressures.

The reaction zone may be a one-stage zone or multiple zones, where carbonation is carried out in multiple stages, and there may be a final stage in which no water is added but carbonation continues or is completed. A variety of desired dust mixers are available that provide for thorough mixing of the carbonate, water, and carbon dioxide feedstocks and may be modified for use in this invention.

One of the features of the apparatus according to the invention is that it is equipped with pump means for removing the atmosphere (gas) from the reaction zone in order to adjust the particle temperature over the desired temperature range, under 1 atm, from 5 to 240°C. That's true. The gas removed from the reaction zone by the C6 pump means is preferably passed through a condenser which concentrates and removes water, and the gas is then recycled to the reaction zone. Preferably, the concentrated water 4 is returned to the reaction zone through nine spray nozzles.

Figure 1 shows a continuous back agitation/defog/flow reactor (ba
ck m1xθσand, plug-, Il'lOW
1 is a schematic flow diagram of an embodiment of the apparatus of the present invention using a rotor;

FIG. 2 is a schematic air diagram of a second embodiment of the device of the invention operated at 2-39 IC pressures. .

Referring to FIG. 1t, a sodium carbonate-containing feed material is added to a mixing feed section l, which material is preferably fed to a first reaction section 2 comprising mixing means 3. Carbon dioxide gas is introduced into the reaction section 2 through the passage 4. The first reaction section 2 is directly connected to the second reaction section 6, which is equipped with a mixing means 1, a carbon dioxide gas introducing means 8, and a water spraying means 9.

Both reaction sections are provided with outlet means 10 and 11, respectively, for removing some of the vapors from the reaction sections, and the removed vapors pass through a concentrator section 12't-, where the moisture in the gas is concentrated; It is circulated from the passage 1rs to the reaction section l. Preferably, carbon dioxide gas from concentration section 1g is recycled to reaction section 1 through passage 14.

The material in reaction section 9 then moves through passage 15 to reaction section 16 in a carbon dioxide atmosphere, where the reaction continues without addition of water and carbonation is completed. Carbon dioxide gas is circulated from the reaction section 16 to the first reaction section 2 through the passage 4. The carbonated material is passed through channel 1'1 to a drying flask 18, after which the bicarbonate formed is removed via channel 19 for distillation and/or storage.

The alternative arrangement of FIG. 2 is substantially the same as that of FIG. 1, except that only one mixing reaction section operating under pressure is used. The carbonate-containing particles are supplied to a mixing supply section 10
1 and then supplied to the reaction section 102. The reaction section 102 includes a mixing means 13, a means 104 for introducing carbon dioxide gas under pressure, and a means for uniformly supplying water.

Steam is led from the reaction section to the concentrating section 101 through a passage 106, where water is concentrated from the gas, and is recycled to the reaction section 102 through a passage 108, and carbon dioxide gas is passed through a passage 109 to the reaction section 102. Circulated.

The partially carbonated product is led from the reaction section 102 with a carbon dioxide-rich atmosphere through the passage 1.1 to the reaction section 11, where it is further carbonated without the addition of water. Continue reacting. The acid saturated product is then led through passage 112 to a cooling doffier 113;
It then passes through passage In for storage and/or grading.

The following examples illustrate some preferred embodiments of the invention, but the invention is not limited thereto.

Example 1 Soda ash' was transferred to the first reaction section using the apparatus shown in FIG.
It was introduced at a rate of 5.321 It'nds per hour at °F. The average residence time of the soda ash in the reaction section is 16 minutes, and the product is conducted from the first reaction section to the second reaction section at a rate of 98,031 bonds per hour, where the carbonic acid Add gas and supply water. Approximately 50% of the soda ash fed to the first reaction section is converted to sodium bicarbonate, and after a reaction time of approximately 15 minutes, a total of 8,
926 pounds of product are introduced into the third reaction section along with some gas. The product remaining in the second reaction section is approximately 809
6 has been converted to hydrogen carbonate. After a residence time of about 10 minutes, the product is then passed to a drying cooler. At this point, the soda ash has been substantially completely converted to sodium bicarbonate. Analysis of the product exiting the drying cooler at a rate of 8,414 pounds per hour revealed 99.2% sodium legate, 0.696% sodium rehydrate, balance inert excipients.

Example 2 Using the apparatus of FIG. 2, soda ash was fed to reaction section 102 at a rate of 5,321 FJζnds per hour at 6°F. It also supplied 92,243 pounds of carbon dioxide per hour and 91,422 pounds of water per hour at a pressure of 5 opsi. The residence time in the reaction section was 30 minutes. The product from reaction 20 part log is more than 60% converted to sodium bicarbonate and is then led to reaction section 111 with some gas without addition of water. After a residence time of 30 minutes there, the product is directed to a drying cooler 115, where it is substantially completely carbonated. Cooler I
When the product was taken out from ll at a rate of 8,418 bonds per hour and analyzed, it was found to be 99J of sodium bicarbonate.
96 and 0.6% of sodium hydroxide.

Example 3 Using concentrated soda ash with a dry bulk density of esof/-e as a raw material, l! Carbonation was carried out using a patch method for 30 minutes in a reaction section having a jacket temperature of SQ'F. Carbon dioxide gas was added to the reaction section as much as necessary. In three separate experiments, the liquid content added to the reaction section was 8.5% based on the weight of the feedstock, 115
%, 30%. Steam was removed from the reaction section and water was concentrated and recycled to the reaction section.

The results are 6 out of 9 as shown in the table below.

Amount of water added 96 (weight) 8°5 16 30 Based on the bulk density table of the dry product, it is clear that when sufficient water is added, the degree of carbonation is high in a short period of time. Ru.

The product was free flowing with little clumps and had a high bulk density desirable for commercial products.

Example 4 Using a batch reactor, 7, 3, 11 and 29% of liquid water were added to sodium carbonate monohydrate based on its weight, and the carbon dioxide-rich atmosphere was removed, the water was concentrated, steam and i
21 Three types of experiments were conducted in which condensed water was recirculated. It showed high carbonation saturation with 95% conversion in less than 15 minutes. In two other examples, sodium sekis carbonate was made by adding 2% and 4% liquid water to the raw materials. These latter examples were somewhat faster, with 99% conversion obtained in less than 10 minutes. There was no evidence of clumping or caking on the reactor walls on the gold side.

Example 5 Dense granules of 105 bond 99-b potassium sulfate were introduced into a reactor with strong internal stirring heated to around 150° II. Wash the system and then carbonate the
- At the same time as the introduction, 7.3% liquid water based on the weight of the raw material was introduced through a spray nozzle. The carbonation saturation reaction was carried out in Example 1.
q) The process proceeded in the same manner as when sodium jQ acid was used. By stopping the reaction after 25 minutes, a free-flowing, granular product was obtained, which had a concentration of 9096 potassium hydrogen chloride.

It should be understood that various modifications can be made to the method and apparatus of the present invention without changing the gist thereof, but these are also included within the scope of the present invention.

[Brief explanation of drawings]

1 and 2 are schematic flow diagrams of a specific example of an apparatus for carrying out the present invention. 23- 1.101-(raw material) mixing supply section, 2.102-first reaction section, 3.7. 103-mixing means, 5-water spraying means, 6-second
Reaction section, 8-Carbon dioxide gas introduction means, 9-Water spraying means, 1$a, 10F-Concentration section, 18.113-Drying cutout, 16.111-Other reaction sections. = 24- Procedural amendment Written by Kazuo Wakasugi, Commissioner of the Patent Office 1, Indication of the case, Patent Application No. 72587 of 1982, 2, Title of the invention, New dry carbonation method 3, Person making the amendment, Relationship to the case, Residence of the patent applicant Location: New Chassis, United States 0885
4, Biscataway, Kingsbridge Road 2
0 Name ChiV-Chi and Dwight C.O.
. INC. Representative: Duncan Dee, Dwight 4, Agent: 530 Address: 153-1 Quarter One Building, 5-1-3 Nishitenma, Kita-ku, Osaka

Claims (1)

[Claims] 1. *In a carbonation saturation method in which a water-soluble alkali metal or ammonium salt raw material of an acid is converted in phase to at least 1596 (by weight) t of a carbonate raw material to a corresponding alkali metal or ammonium bicarbonate salt, The carbonate raw material in the form of solid particles is reacted with liquid water under a total pressure of 1 l-10 in a fluorine dioxide-containing atmosphere to form a solution of the carbonate reactant within the individual particles and the heavy acid produced therein. The salt product is crystallized and the carbonate raw material, liquid water and carbon dioxide gas are combined for 5 to 6 hours.
The reaction is carried out by contacting the particulate reactants for 0 minutes (the longer the reaction time, the higher the conversion) while maintaining the temperature of the particulate reactants at about 125°F to 240'F', whereupon a) relatively dry carbon dioxide gas and an aliquot of liquid water are added during substantially the entire duration of the reaction, with the added liquid water aliquot being between 2 and 50% (by weight) of the carbonate (To#) and removed as vapor during the carbonation reaction. Additional liquid water is added to compensate for some of the water lost, such that the liquid water in the reaction mixture is (1) sufficient to ensure substantially uniform contact of the liquid water with the solid particulate feedstock; ('b) not so much as to cause agglomeration and caking of the granular material, and ('b) sufficient to maintain the temperature of the granular material and neutralize the amount of heat released during the acid saturation reaction; In order to bring the granular raw material into direct contact with liquid water and diluted acid gas, the granular raw material lumps are mixed, and (0) the pressure of carbon dioxide gas is adjusted to 0.2 to 0 when the total pressure is 1 atm.
．． When the partial pressure is 9 and the total pressure is 9, keep the partial pressure proportionally higher; (d) evaporate liquid water near the granular raw material to cool the reaction particles; Ce) evaporate water. 1. A dry carbonation method characterized by: cooling the reactant particles; and removing a water vapor-containing atmosphere to maintain the reactant particles in the temperature range mentioned above. 2. A claim in which the water vapor removed in step (e) is concentrated and at least a portion of the concentrate or an additional amount of liquid water equal to the amount of water vapor removed is the additional liquid water added to step (a). The method described in item 1. 3. A process according to claim 1, wherein the liquid water added in step (a) is in the form of water or an aqueous solution of a water-soluble alkali metal or ammonium carbonate, hydroxide or bicarbonate. 4. The method of claim 1, wherein carbon dioxide gas is added during the entire reaction period and liquid water is added during all but the final portion of the reaction period. 5. The reaction is 1 g:, the partial pressure of carbon dioxide is o at the total pressure of the pressure,
2. A process according to claim 1, wherein the process is carried out under conditions of 4 to 0.7 atmospheres and buffing of the gas mixture in the reaction zone with water vapor and other inert gases. 6. The method of claim 5, wherein the temperature of the particulate carbonate feedstock is maintained in the range of 160°F to 240°F and the carbonation reaction is carried out for 30 to 40 minutes. 7. The method according to claim 1, wherein substantially all of the phosphoric acid in the water-soluble carbonate raw material is converted to bicarbonate. 8. Claim M in which the water-soluble carbonate raw material is selected from the group consisting of anhydrous sodium carbonate, anhydrous potassium carbonate, anhydrous ammonium carbonate, and anhydrous double back acid sodalite.
A method according to any one of items 1 to 7. 9. Claim 1. The water-soluble carbonate raw material is anhydrous sodium carbonate, the total pressure is 1 to 3 atm, and the reaction time is 20 to 45 minutes. or the method described in Section 7. 10. If the water-soluble carbonate raw material is anhydrous sodium carbonate, and the aliquot of liquid water added in step (a) is 8.5 to 30% (by weight) based on the anhydrous sodium carbonate, the envy acid saturation is 10. The method of claim 1 or 9, which is carried out at a temperature and reaction time sufficient to convert 15 to 80% of anhydrous sodium carbonate into 1-sodium bicarbonate. 11. The water-soluble amate salt raw material is sodium carbonate hydrate and
3- selected from the group consisting of sodium sesquicarbonate and the aliquot of liquid water added in step (a) containing 7 to 30% (by weight) of sodium carbonate lhydrate or 2 to 496% (by weight) of sodium sesquicarbonate; 8. The method according to any one of claims 1 to 7, wherein: