CN112794347A

CN112794347A - By using CO2Combined device and process for preparing heavy alkali by drying and carbonizing ammonium chloride in concentrated gas

Info

Publication number: CN112794347A
Application number: CN202110153921.1A
Authority: CN
Inventors: 李黎峰; 胡斌; 胡书亚; 张沫; 李相福; 方华东; 陈学峰; 李林; 冯青天; 孔维斌; 常佳伟; 孙颖
Original assignee: China Tianchen Engineering Corp
Current assignee: China Tianchen Engineering Corp
Priority date: 2021-02-04
Filing date: 2021-02-04
Publication date: 2021-05-14

Abstract

The invention provides the utilization of CO₂A combined device and a process for preparing heavy alkali by drying ammonium chloride and carbonizing concentrated gas solve the technical problems of serious pollution and high process cost of an ammonium chloride drying device in the prior art. The embodiment of the invention provides the utilization of CO₂Combined device for drying ammonium chloride and carbonizing concentrated gas to prepare heavy alkali by utilizing CO₂The concentrated gas is used as fluidizing gas, the first fluidizing gas generated after drying wet ammonium chloride is subjected to step-by-step treatment by using a dedusting and washing device to obtain ammonium chloride washing water and liquid containing free ammonia, and the ammonium chloride washing water generated by grading can be sent to produce ammonia water for ammonia desulphurization by an ammonia process of a thermal power plant matched with an integrated alkali plant; namely, the invention adopts the dust removal washing device to carry out the step-by-step treatment on the fluidizing gas to obtain the wastewater which is fully beneficialWhen the wastewater is used, the wastewater is not discharged, and no additional wastewater treatment system is needed for treating the wastewater containing chlorine and ammonia, so that the process cost is reduced, and the pollution to the environment is reduced.

Description

By using CO2Combined device and process for preparing heavy alkali by drying and carbonizing ammonium chloride in concentrated gas

Technical Field

The invention relates to the field of chemical production and manufacturing, in particular to a combined device and a process for preparing heavy alkali by drying and carbonizing ammonium chloride by using CO2 concentrated gas.

Background

The soda ash industry is not only a basic chemical raw material, but also a bulk product directly put on the market, and belongs to one of the top ten products of the chemical industry in terms of production scale. At present, three main methods for producing soda ash in various countries exist: the ammonia-soda process, the combined-soda process and the natural soda process are different in raw materials and production methods and have different characteristics, for example, the ammonia-soda process cannot separate original salt and limestone and is close to the production places of the salt and the limestone; the combined alkali method needs to be matched with an ammonia synthesis plant; trona processing must be local with abundant trona resources, etc.

The combined alkali method is also called Hou's alkali making method, and features that the raw material ammonia is produced in the form of ammonium chloride product, and two kinds of products, namely soda ash and ammonium chloride, are produced simultaneously. The ammonia and the carbon dioxide are both from an ammonia synthesis device, and the soda ash device can only be produced together with the ammonia synthesis device and cannot be independently arranged. The combined soda process accounts for more than 50% of the prior soda ash process in China.

One of the products of the combined alkali method is ammonium chloride which is obtained by drying wet ammonium chloride. The wet ammonium chloride from the centrifuge of the traditional drying process is sent into the fluidized bed by a belt conveyer, and is heated, dried and cooled by using hot air as a fluidizing medium and steam. At present, the process has the following problems:

(1) the belt conveyor adopted by the process is an air-to-air device, and free ammonia in wet ammonium chloride is easy to volatilize, so that the environmental pollution and the severe operating environment are caused.

(2) The traditional ammonium chloride drying process is open drying, namely, the tail gas at the top of a fluidized bed needs to be subjected to dry dust removal by a bag-type dust remover or is emptied after wet dust removal by a spray tower. Due to the existence of ammonium chloride, white smoke may be generated by the discharged high-temperature wet tail gas, and the national environmental emission standard is continuously improved, so that the ammonium chloride drying process for dry dedusting is not applicable any more. The wet ammonium chloride contains certain free ammonia, so that the dry tail gas contains certain ammonia gas, a large amount of water or acid is needed for dedusting and ammonia removal in the wet dedusting and drying ammonium chloride process, the maximum shrinkage in the combined alkali process is only 151.15kg/t alkali, namely, the mother liquor only shrinks about 0.055m3 of water per 1 ton of ammonium or ammonia produced, and a large amount of washing water easily causes the problems of expansion of the combined alkali mother liquor, increased ammonia evaporation load, difficult treatment of acid washing waste liquid, high treatment process cost and the like.

Therefore, the traditional ammonium chloride drying process does not meet the production requirements of environmental protection and stable operation.

Disclosure of Invention

In view of the above, the invention provides a combined device and a process for preparing heavy alkali by drying and carbonizing ammonium chloride with concentrated CO2 gas, and solves the technical problems of serious pollution, high process cost and unstable operation of an ammonium chloride drying device in the prior art.

For the purpose of making the objects, technical means and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings.

According to one aspect of the invention, embodiments of the invention provide a method for utilizing CO₂The combined device for drying ammonium chloride and carbonizing concentrated gas to prepare heavy alkali comprises:

a heating device for heating CO₂Heating the concentrated gas to produce CO₂Fluidizing gas;

a dryer arranged at the downstream of the heating device, wherein the bottom of the dryer is introduced with CO generated by the heating device₂A fluidizing gas, the dryer heating the wet ammonium chloride to a process temperature, producing dry ammonium chloride, water vapor, ammonia gas, and carbon dioxide, wherein the water vapor, the ammonia gas, and the carbon dioxide are with the CO₂The fluidizing gas is discharged from the top of the dryer, the water vapor, the ammonia gas, the carbon dioxide and the CO₂The fluidizing gas constitutes first fluidizing gas;

the dust removal washing device is arranged at the downstream of the dryer and used for processing the first fluidizing gas step by step to obtain solid ammonium chloride, ammonium chloride washing water and liquid containing free ammonia, the fluidizing gas output by the first fluidizing gas after passing through the dust removal washing device is a second fluidizing gas, and the second fluidizing gas comprises gas CO₂(ii) a And

the second fluidizing gas output by the dedusting and washing device is input into the carbon compression device, and the carbon compression device mixes the second fluidizing gas with ammonia brine to generate heavy alkali;

preferably, wherein said CO is₂The concentrated gas is CO discharged from a synthetic ammonia plant₂And (4) concentrating.

In an embodiment of the present invention, the dust removing washing apparatus includes: a dry dedusting apparatus disposed downstream of the dryer, the dry dedusting apparatus configured to dedust the first fluidizing gas to produce solid ammonium chloride; and a wet scrubbing apparatus disposed downstream of the dry dedusting apparatus, the wet scrubbing apparatus configured to progressively scrub the first fluidization gas to produce a staged ammonium chloride scrubbing water and a liquid containing free ammonia.

In an embodiment of the invention, the wet scrubbing apparatus comprises:

a dechlorination scrubber arranged at the downstream of the dry dust removal device and used for scrubbing the first fluidization gas to generate ammonium chloride scrubbing water; and

and the ammonia removal condenser is arranged at the downstream of the chlorine removal washing tower and is used for washing the first fluidizing gas treated by the chlorine removal washing tower to generate condensate containing free ammonia.

In an embodiment of the invention, the wet scrubbing apparatus further comprises:

and the ammonia removal washing tower is arranged at the downstream of the ammonia removal condenser and is used for washing the first fluidizing gas treated by the ammonia removal condenser to generate washing water containing free ammonia.

In an embodiment of the present invention, the compression carbonization apparatus includes: a compressor disposed downstream of said dust removal scrubbing apparatus, said compressor compressing said second fluidizing gas to produce compressed carbon dioxide; and a carbonator disposed downstream of the compressor, the carbonator reacting the compressed carbon dioxide with an ammonia brine to produce a heavy base; and/or

The dry dust removing apparatus includes: a cyclone separator; and/or a bag-type dust collector.

In one embodiment of the present invention, CO is utilized₂The integrated device for drying ammonium chloride and carbonizing heavy alkali by concentrated gas also comprises:

a feed mixing device disposed upstream of the dryer, the feed mixing device mixing a wet ammonium chloride cake and dry ammonium chloride to produce wet ammonium chloride, and inputting the wet ammonium chloride into the dryer; and/or

The inlet of the discharging device is connected with the dryer and the dedusting and washing device, and one outlet of the discharging device is connected with the feeding mixing and conveying device;

and the discharging device is used for treating the dry ammonium chloride generated by the dryer and the solid ammonium chloride generated by the dedusting and washing device to generate dry ammonium chloride.

As a second aspect of the invention, embodiments of the invention provide a method for utilizing CO₂The combined process of drying ammonium chloride and carbonizing concentrated gas to prepare heavy alkali includes the following steps:

introducing CO₂Inputting the concentrated gas into a heating device for heating to generate CO₂Fluidizing gas, wherein said CO₂The pressure of the concentrated gas is 0.05-0.15 MPa;

introducing the CO into a reaction vessel₂The fluidized gas is introduced into a dryer from the bottom of the dryer, the wet ammonium chloride is input into the dryer, and the dryer heats the wet ammonium chloride to a process temperature to generate dry ammonium chloride, water vapor, ammonia gas and carbon dioxide, wherein the water vapor, the ammonia gas and the carbon dioxide are mixed with the CO₂The fluidizing gas is discharged from the top of the dryer, the water vapor, the ammonia gas, the carbon dioxide and the CO₂The fluidizing gas constitutes first fluidizing gas;

inputting the first fluidizing gas into a dedusting and washing device for step-by-step treatment to obtain solid ammonium chloride, ammonium chloride washing water and liquid containing free ammonia, wherein the fluidizing gas output after the first fluidizing gas passes through the dedusting and washing device is a second fluidizing gas, and the second fluidizing gas comprises gas CO₂(ii) a And

the second fluidizing gas is mixed with an ammonia brine in a compressed carbonation device to produce a heavy base.

In one embodiment of the invention, the dust removal scrubbing apparatus comprises a dry dust removal device disposed downstream of the dryer, and a wet scrubbing device disposed downstream of the dry dust removal device;

wherein, the first fluidization gas is input into a dedusting and washing device for step-by-step treatment to obtain solid ammonium chloride, ammonium chloride washing water and liquid containing free ammonia, and the method comprises the following steps:

inputting the first fluidizing gas into the dry dust removal equipment for dust removal treatment to generate solid ammonium chloride;

and inputting the first fluidizing gas subjected to dust removal treatment by the dry dust removal equipment into the wet washing equipment for washing step by step to generate ammonium chloride washing water and liquid containing free ammonia in a grading manner.

In one embodiment of the invention, the wet scrubbing equipment comprises a chlorine removal scrubbing tower arranged at the downstream of the dry dust removal equipment, and an ammonia removal condenser arranged at the downstream of the chlorine removal scrubbing tower;

wherein, will carry out the first fluidization gas input after the dust removal processing through dry dust collecting equipment to wash in the wet scrubbing equipment step by step, produce ammonium chloride wash water and contain the liquid of free ammonia in grades, include:

inputting the first fluidizing gas subjected to dust removal treatment by the dry dust removal equipment into the dechlorination washing tower for washing to generate ammonium chloride washing water;

and inputting the first fluidization gas washed by the dechlorination washing tower into the ammonia removal condenser for secondary washing to generate condensate containing free ammonia.

In an embodiment of the invention, the wet scrubbing apparatus further comprises an ammonia removal scrubber arranged downstream of the ammonia removal condenser;

wherein, will carry out the first fluidization gas input after the dust removal processing through dry-type dust collecting equipment to wash in the wet-type scrubbing equipment step by step, produce ammonium chloride wash water and the liquid that contains free ammonia in grades, still include:

inputting the first fluidized gas washed by the ammonia removal condenser into the ammonia removal washing tower for second washing to generate washing water containing free ammonia;

preferably, the first and second liquid crystal materials are,

at the time of the introduction of the CO₂The fluidized gas is introduced into the dryer from the bottom of the dryer, and the wet ammonium chloride is introduced into the dryer by using CO₂The combined process for preparing the heavy alkali by drying and carbonizing the ammonium chloride in the concentrated gas also comprises the following steps:

mixing the wet ammonium chloride filter cake and dry ammonium chloride in a feed mixing device to produce wet ammonium chloride;

preferably, the first and second liquid crystal materials are,

by using CO₂The combined device for drying the ammonium chloride and carbonizing the concentrated gas to prepare the heavy alkali further comprises a discharging device, an inlet of the discharging device is connected with the dryer and the dedusting and washing device, and an outlet of the discharging device is connected with the feeding mixing and conveying device;

wherein CO is utilized₂The combined process for preparing the heavy alkali by drying and carbonizing the ammonium chloride in the concentrated gas also comprises the following steps:

treating dry ammonium chloride generated in the dryer and solid ammonium chloride generated by the dedusting and washing device to generate dry ammonium chloride;

inputting the dry ammonium chloride to the feed mixing device.

The embodiment of the invention provides a method for utilizing CO₂Combined device for drying ammonium chloride and carbonizing heavy alkali by concentrated gas, and CO discharged from synthetic ammonia plant₂CO after dense gas heating₂The concentrated gas is used as fluidizing gas, the first fluidizing gas generated after drying wet ammonium chloride is subjected to step-by-step treatment by using a dedusting and washing device to obtain solid ammonium chloride, ammonium chloride washing water and liquid containing free ammonia, and the ammonium chloride washing water generated by grading can be sent to produce ammonia water for ammonia desulphurization by an ammonia process of a thermal power plant matched with an integrated alkali plant; and can also be sent to a combined alkali semi-ammonia still tower or a II process as water supplement. The liquid containing free ammonia generated by the grading is sent to an ammonia still for evaporation to recover ammonia and carbon dioxide. The invention adopts the dust removal washing device to fully utilize the waste water obtained by the step-by-step treatment of the fluidizing gas, and the waste water is not discharged, and no additional waste water treatment system is needed to treat the waste water containing chlorine and ammonia, thereby not only reducing the process cost, but also reducing the pollution to the environment.

Drawings

FIG. 1 shows a CO utilization system according to an embodiment of the present invention₂The structure schematic diagram of a combined device for preparing the heavy alkali by drying and carbonizing the concentrated gas by ammonium chloride;

FIG. 2 shows a CO utilization system according to another embodiment of the present invention₂The flow diagram of the combined process for preparing the heavy alkali by drying and carbonizing the concentrated gas by ammonium chloride;

FIG. 3 shows a CO utilization system according to another embodiment of the present invention₂The structure schematic diagram of a combined device for preparing the heavy alkali by drying and carbonizing the concentrated gas by ammonium chloride;

FIG. 4 shows a CO utilization system according to another embodiment of the present invention₂The flow diagram of the combined process for preparing the heavy alkali by drying and carbonizing the concentrated gas by ammonium chloride;

FIG. 5 shows a CO utilization system according to another embodiment of the present invention₂The structure schematic diagram of a combined device for preparing the heavy alkali by drying and carbonizing the concentrated gas by ammonium chloride;

FIG. 6 shows a CO utilization system according to another embodiment of the present invention₂The flow diagram of the combined process for preparing the heavy alkali by drying and carbonizing the concentrated gas by ammonium chloride;

FIG. 7 shows a CO utilization system according to another embodiment of the present invention₂The structure schematic diagram of a combined device for preparing the heavy alkali by drying and carbonizing the concentrated gas by ammonium chloride;

FIG. 8 shows a CO utilization system according to another embodiment of the present invention₂The flow diagram of the combined process for preparing the heavy alkali by drying and carbonizing the concentrated gas by ammonium chloride;

FIG. 9 shows a CO utilization system according to another embodiment of the present invention₂The structure schematic diagram of a combined device for preparing the heavy alkali by drying and carbonizing the concentrated gas by ammonium chloride;

FIG. 10 shows a CO utilization system according to another embodiment of the present invention₂The flow diagram of the combined process for preparing the heavy alkali by drying and carbonizing the concentrated gas by ammonium chloride;

FIG. 11 shows a CO utilization system according to another embodiment of the present invention₂The structure schematic diagram of a combined device for preparing the heavy alkali by drying and carbonizing the concentrated gas by ammonium chloride;

FIG. 12 is a schematic diagram of another embodiment of the present invention for utilizing CO₂The flow diagram of the combined process for preparing the heavy alkali by drying and carbonizing the concentrated gas by ammonium chloride;

FIG. 13 shows a process for producing a polymer using CO according to comparative example 1₂Combination device for drying ammonium chloride and carbonizing heavy alkali by concentrated gasA schematic diagram;

FIG. 14 shows a process for utilizing CO according to comparative example 2₂The structure schematic diagram of a combined device for preparing the heavy alkali by drying and carbonizing the concentrated gas by ammonium chloride;

FIG. 15 shows a process for producing a polymer using CO according to comparative example 3₂The structure of the combined device for drying ammonium chloride and carbonizing heavy alkali by concentrated gas is shown schematically.

Reference numerals:

a heating device 1; a dryer 2; dust removal washing device 3: a dry dust removal device 31, a wet scrubbing device 32, a chlorine removal scrubbing tower 321, an ammonia removal condenser 322 and an ammonia removal scrubbing tower 323; a carbon compression device 4; a feed mixing device 5; a discharging device 6; the pressurizing device 7, the first pressurizing device 71, the second pressurizing device 72;

ammonia brine H; heavy base M; wet ammonium chloride filter cake a; dry ammonium chloride B; solid ammonium chloride C; liquid D containing free ammonia, condensate D1 containing free ammonia, and washing water D2 containing free ammonia; washing water E containing ammonium chloride; CO2 rich gas F; the first fluidization gas G1; second fluidization gas G2.

Detailed Description

In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise. All directional indicators in the embodiments of the present invention (such as upper, lower, left, right, front, rear, top, bottom … …) are only used to explain the relative position, motion, etc. of the components in a particular position (as shown in the drawings), and if the particular position is changed, the directional indicator is changed accordingly. Furthermore, the terms "include" and "have," as well as any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those steps or elements listed, but may alternatively include other steps or elements not listed, or inherent to such process, method, article, or apparatus.

Furthermore, reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the invention. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein can be combined with other embodiments.

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1:

fig. 1 is a schematic structural diagram of a combined apparatus for drying ammonium chloride and carbonizing heavy alkali by using a concentrated CO2 gas according to an embodiment of the present invention, and as shown in fig. 1, the combined apparatus for drying ammonium chloride and carbonizing heavy alkali by using a concentrated CO2 gas includes:

a heating device 1; a drier 2 arranged at the downstream of the heating device 1, wet ammonium chloride is input into one end of the drier 2, and CO generated by the heating device 1 is introduced into the bottom of the drier 2₂Fluidizing gas; a dust removal washing device disposed downstream of the dryer 2; and a carbon compression device 4.

Fig. 2 is a schematic flow chart of a combined process for drying ammonium chloride and carbonizing heavy alkali by using a concentrated CO2 gas, which is performed by using the combined apparatus for drying ammonium chloride and carbonizing heavy alkali by using a concentrated CO2 gas shown in fig. 1, and as shown in fig. 2, the combined process for drying ammonium chloride and carbonizing heavy alkali by using a concentrated CO2 gas comprises the following steps:

step S101: the CO2 concentrated gas F directly discharged from the synthetic ammonia plant is input into a heating device 1 for heating to generate CO₂Fluidizing gas, wherein the pressure of the CO2 concentrated gas F is 0.05-0.15 MPa;

step S102: CO heated by the heating device 1₂The fluidizing gas is introduced from the bottom of the dryer 2A dryer 2 for feeding wet ammonium chloride to the dryer 2, the dryer 2 heating the wet ammonium chloride to a process temperature to produce dry ammonium chloride B, water vapor, ammonia gas and carbon dioxide, wherein the water vapor, ammonia gas and carbon dioxide are accompanied by CO₂The fluidizing gas is discharged from the top of the dryer 2, and the water vapor, ammonia gas, carbon dioxide and CO are discharged₂The fluidizing gas constitutes first fluidizing gas G1;

step S103: inputting the first fluidization gas G1 into a dedusting and washing device 3 for step-by-step treatment to obtain solid ammonium chloride C, ammonium chloride washing water and liquid D containing free ammonia, wherein the fluidization gas output after the first fluidization gas G1 passes through the dedusting and washing device is a second fluidization gas G2, and the second fluidization gas G2 comprises gas CO₂(ii) a Wherein, the generated washing water E containing ammonium chloride can be sent to produce ammonia water for the ammonia desulphurization of the thermal power plant matched with the combined alkali plant; and can also be sent to a combined alkali semi-ammonia still tower or a II process as water supplement. The liquid D containing free ammonia generated by the classification is sent to an ammonia still for evaporation to recover ammonia and carbon dioxide.

Step S104: the second fluidization gas G2 is mixed with the ammoniacal brine H in the compressed carbonization unit to produce heavy alkali.

Second fluidizing gas G2 is fed to CO after the compressed carbonization device₂The fluidizing gas (i.e. the second fluidizing gas G2) is compressed and then sent to a carbonizer to react with the ammoniacal brine H to produce the heavy alkali (sodium bicarbonate crystals). Excess CO₂The gas may be vented at a high point prior to the compressor.

According to the combined device for preparing the heavy alkali by drying the ammonium chloride and carbonizing the ammonium chloride by using the CO2 concentrated gas, the CO2 concentrated gas F heated by the CO2 concentrated gas is used as the fluidizing gas, the first fluidizing gas G1 generated by drying wet ammonium chloride is subjected to step-by-step treatment by using the dedusting and washing device to obtain the solid ammonium chloride C, the ammonium chloride washing water and the liquid D containing free ammonia, and the ammonium chloride washing water E generated by grading can be sent to prepare the ammonia water for ammonia desulphurization by the ammonia process of the thermal power plant matched with the combined alkali plant; and can also be sent to a combined alkali semi-ammonia still tower or a II process as water supplement. The liquid D containing free ammonia generated by the classification is sent to an ammonia still for evaporation to recover ammonia and carbon dioxide. The invention adopts the dust removal washing device to fully utilize the waste water obtained by the step-by-step treatment of the fluidizing gas, and the waste water is not discharged, and no additional waste water treatment system is needed to treat the waste water containing chlorine and ammonia, thereby not only reducing the process cost, but also reducing the pollution to the environment.

Example 2:

fig. 3 shows a combined apparatus for drying ammonium chloride and carbonizing heavy alkali by using concentrated CO2 gas according to another embodiment of the present invention, and as shown in fig. 3, the dust-removing washing apparatus 3 includes: a dry dust removing device 31 disposed downstream of the dryer 2; and a wet scrubbing apparatus 32 disposed downstream of the dry dust removal apparatus 31. Fig. 4 is a schematic flow chart of a combined process for drying ammonium chloride and carbonizing heavy alkali by using a concentrated CO2 gas, which is performed by using the combined apparatus for drying ammonium chloride and carbonizing heavy alkali by using a concentrated CO2 gas shown in fig. 3, and in combination with fig. 3 and 4, the combined process for drying ammonium chloride and carbonizing heavy alkali by using a concentrated CO2 gas comprises the following steps:

step S102: introducing CO₂The fluidized gas is introduced into the dryer 2 from the bottom of the dryer 2, wet ammonium chloride is input into the dryer 2, the dryer 2 heats the wet ammonium chloride to the process temperature, and dry ammonium chloride B, water vapor, ammonia gas and carbon dioxide are generated, wherein the water vapor, the ammonia gas and the carbon dioxide are accompanied by CO₂The fluidizing gas is discharged from the top of the dryer 2, and the water vapor, ammonia gas, carbon dioxide and CO are discharged₂The fluidizing gas constitutes first fluidizing gas G1;

step S1031: inputting the first fluidization gas G1 into the dry-type dust removal equipment 31 for dust removal treatment to generate solid ammonium chloride C;

step S1032: the first fluidization gas G1 after being dedusted by the dry dedusting device 31 is input into the wet scrubbing device 32 for being scrubbed step by step to generate ammonium chloride scrubbing water and liquid D containing free ammonia by classification.

The first fluidizing gas G1 is classified through steps S1031 and S1032, that is, the first fluidizing gasThe fluidizing gas output after the gas G1 passes through the dedusting and washing device is second fluidizing gas G2, and the second fluidizing gas G2 comprises gas CO₂；

Alternatively, the dry dust removing apparatus 31 may include only the cyclone. The dry dust removing apparatus 31 may also include only a bag-type dust remover. The dry dust removing apparatus 31 may include a cyclone separator and a bag-type dust collector disposed downstream of the cyclone separator.

This example further embodies step S103 in example 1, that is, in the embodiment of the present invention, a specific washing process in which the first liquefied gas G1 is washed in stages in the dust removal washing device is performed, that is, most of the solid ammonium chloride C is removed, then the ammonium chloride is removed, and then the free ammonia is removed, so that the liquefied gas can be classified, and the washing water or the solid ammonium chloride C obtained by the classification can be uniformly reused.

Example 3:

fig. 5 shows a combined apparatus for drying ammonium chloride and carbonizing heavy alkali by using a concentrated CO2 gas according to another embodiment of the present invention, and as shown in fig. 5, the wet scrubber 32 includes a dechlorination scrubber 321 disposed downstream of the dry dust collector 31, an ammonia removal condenser 322 disposed downstream of the dechlorination scrubber 321, and an ammonia removal scrubber 323 disposed downstream of the ammonia removal condenser 322; fig. 6 is a schematic flow chart of a combined process for drying ammonium chloride and carbonizing heavy alkali by using a concentrated CO2 gas, which is performed by using the combined apparatus for drying ammonium chloride and carbonizing heavy alkali by using a concentrated CO2 gas shown in fig. 5, and in combination with fig. 5 and 6, the combined process for drying ammonium chloride and carbonizing heavy alkali by using a concentrated CO2 gas comprises the following steps:

step S102: introducing CO₂The fluidizing gas is introduced into the dryer 2 from the bottom of the dryer 2, and wet ammonium chloride is introduced into the dryer 2A dryer 2, the dryer 2 heating the wet ammonium chloride to a process temperature to produce dry ammonium chloride B, water vapor, ammonia gas and carbon dioxide, wherein the water vapor, ammonia gas and carbon dioxide are accompanied by CO₂The fluidizing gas is discharged from the top of the dryer 2, and the water vapor, ammonia gas, carbon dioxide and CO are discharged₂The fluidizing gas constitutes first fluidizing gas G1;

step S10321: inputting the first fluidizing gas G1 subjected to the dust removal treatment by the dry dust removal device 31 into a dechlorination washing tower 321 for washing to generate ammonium chloride washing water;

step S10322: inputting the first fluidization gas G1 washed by the dechlorination washing tower 321 into the ammonia removal condenser 322 for washing to generate condensate D1 containing free ammonia;

step S10323: the first liquefied gas G1 washed by the ammonia removal condenser 322 is input to the ammonia removal washing tower 323 for washing to generate washing water D2 containing free ammonia.

After the step S1031, the step S10321, the step S10322 and the step S10323, the first fluidization gas G1 is classified, that is, the fluidization gas output by the first fluidization gas G1 after passing through the dust-removing washing device is the second fluidization gas G2, and the second fluidization gas G2 includes the gas CO₂；

Step S104: second fluidizing gas G2 (i.e. CO)₂Stream gas) is mixed with ammoniacal brine H in a compressed carbonation plant to produce heavy alkali.

Compared with the example 2, in the embodiment of the present invention, when the first liquefied gas G1 is treated, the wet washing step, that is, step S1032, specifically, three times of washing for sequentially removing ammonium chloride and free ammonia, and sequentially removing free ammonia and ammonium chloride in the first liquefied gas G1, respectively, may be performed, for example, by removing the free ammonia generated from the obtained washing water D2 containing free ammonia as washing water by a heavy alkali filter or by other methods.

Example 4:

since the wet ammonium chloride in step S102 is a mixture of wet ammonium chloride and partially dried ammonium chloride B, the fluidized bed is seriously scabbed due to the reduction of the fluidized bed feed water content at the time of drying in the dryer 2, and frequent cleaning is required. Therefore, fig. 7 shows a combined apparatus for drying ammonium chloride and carbonizing heavy alkali by using a concentrated CO2 gas according to another embodiment of the present invention, as shown in fig. 7, the combined apparatus for drying ammonium chloride and carbonizing heavy alkali by using a concentrated CO2 gas further includes a feeding mixing device 5 disposed upstream of the dryer 2, fig. 8 shows a schematic flow chart of a combined process for drying ammonium chloride and carbonizing heavy alkali by using a concentrated CO2 gas by using the combined apparatus for drying ammonium chloride and carbonizing heavy alkali by using a concentrated CO2 gas shown in fig. 7, and in conjunction with fig. 7 and fig. 8, the combined process for drying ammonium chloride and carbonizing heavy alkali by using a concentrated CO2 gas includes the following steps:

step S100: the wet ammonium chloride cake a and dry ammonium chloride B are mixed in a feed mixing device 5 to produce wet ammonium chloride. That is, the wet ammonium chloride cake a and the dry ammonium chloride B are mixed in the feed mixing device 5 before the wet ammonium chloride is fed into the dryer 2 to be dried, and when the wet ammonium chloride generated after sufficient mixing is dried in the dryer 2, the probability of fluidized bed scaling in the dryer 2 is reduced.

step S10323: the first liquefied gas G1 washed by the ammonia removal condenser 322 is input to the ammonia removal washing tower 323 for the third stage of washing to produce washing water D2 containing free ammonia.

In contrast to example 3, the combined process of ammonium chloride drying and carbonation for heavy caustic utilizing a concentrated CO2 gas of the present example mixes wet ammonium chloride cake a and dry ammonium chloride B in feed mixing device 5 to produce wet ammonium chloride. The wet ammonium chloride cake a and the dry ammonium chloride B are mixed in the feed mixing device 5 before step S101 (i.e., before the wet ammonium chloride is fed to the dryer 2 for drying), and the probability of fluidized bed scarring in the dryer 2 is reduced when the wet ammonium chloride produced after thorough mixing is dried in the dryer 2.

Example 5:

since the wet ammonium chloride cake a and the dry ammonium chloride B need to be mixed in the feed mixing device 5 in step S100, the combined device for drying and carbonizing ammonium chloride by using concentrated CO2 gas for producing heavy alkali in the embodiment of the present invention, as shown in fig. 9, further includes: and the inlet of the discharging device 6 is connected with the dryer 2 and the dedusting and washing device 3, and the outlet of the discharging device 6 is connected with the feeding mixing and conveying device. Fig. 10 is a schematic flow chart of a combined process for drying ammonium chloride and carbonizing heavy alkali by using a concentrated CO2 gas by using the combined apparatus for drying ammonium chloride and carbonizing heavy alkali by using a concentrated CO2 gas shown in fig. 9, and the combined process for drying ammonium chloride and carbonizing heavy alkali by using a concentrated CO2 gas includes the following steps, as shown in fig. 9 and fig. 10:

step S100: the wet ammonium chloride cake a containing 6% wt of water and the dry ammonium chloride B returned from the discharge unit 6 were mixed in the feed mixing unit 5 to produce wet ammonium chloride, wherein the dry ammonium chloride B was fed to the feed mixing unit 5 at a rate of 13000 Kg/h. That is, the wet ammonium chloride cake a and the dry ammonium chloride B are mixed in the feed mixing device 5 before the wet ammonium chloride is fed into the dryer 2 to be dried, and when the wet ammonium chloride generated after sufficient mixing is dried in the dryer 2, the probability of fluidized bed scaling in the dryer 2 is reduced.

Step S101: CO2 rich gas F from a synthetic ammonia plant is treated at 35000Nm³The speed of the reaction is input into the heating device 1 to be heated to 190 ℃ to generate CO₂Fluidizing gas, wherein the pressure of CO2 concentrated gas F is 0.1 MPaG;

step S102: introducing CO₂Introducing fluidizing gas into the dryer 2 from the bottom of the dryer 2, inputting the wet ammonium chloride obtained in the step S100 into the dryer 2, heating the wet ammonium chloride to a process temperature by the dryer 2, and generating dry ammonium chloride B, water vapor, ammonia gas and carbon dioxide, wherein the water vapor, the ammonia gas and the carbon dioxide are accompanied by CO₂The fluidizing gas is discharged from the top of the dryer 2, and the water vapor, ammonia gas, carbon dioxide and CO are discharged₂The fluidizing gas constitutes first fluidizing gas G1; wherein dry ammonium chloride B is conveyed to the discharge device 6, the temperature of the first fluidizing gas G1 at this time being about 80 ℃;

step S1031: inputting the first fluidization gas G1 into the dry-type dust removal equipment 31 for dust removal treatment to generate solid ammonium chloride C; conveying solid ammonium chloride C to a discharging device 6; that is, in step S1031, the solid ammonium chloride C in the first fluidization gas G1 is mostly removed;

step S10311: the discharging device 6 processes the dry ammonium chloride B generated by the dryer 2 and the solid ammonium chloride C generated by the dry dust removal equipment 31 to generate dry ammonium chloride B, and transmits part of the dry ammonium chloride B to the feeding and mixing device 5, and in the feeding and mixing device 5, the wet ammonium chloride filter cake a and the dry ammonium chloride B are fully mixed to generate wet ammonium chloride. The effect of fully utilizing the dry ammonium chloride B is achieved.

Step S10321: inputting the first fluidizing gas G1 subjected to dust removal treatment by the dry dust removal device 31 into a dechlorination washing tower 321 for washing to generate ammonium chloride washing water, wherein the dechlorination washing tower 321 performs circulating spraying through a circulating pump and a circulating cooler to wash ammonium chloride in the first fluidizing gas G1 to generate ammonium chloride washing water, the ammonium chloride contained in the washing water is about 3.2kg/h, and the discharged washing water is about 63 kg/h. At this time, the temperature of the first liquefied gas G1 discharged after passing through the dechlorination scrubber 321 was about 50 ℃.

Step S10322: the first fluidizing gas G1 washed by the dechlorination washing tower 321 is input into the ammonia-removing condenser 322 for washing to generate condensate D1 containing free ammonia, and the discharge speed of the condensate D1 containing free ammonia is 3.2m³The concentration of ammonia is titer (about 137kg/h), the condensate D1 containing free ammonia can be recycled by an ammonia still and further used as water supplement to enter a combined alkali process system, and the temperature of the first fluidization gas G1 after passing through the ammonia removal washing tower 323 is about 25 ℃.

Step S10323: the first fluidization gas G1 washed by the chlorine removal washing tower 321 is input into the ammonia removal washing tower 323 for washing to generate washing water D2 containing free ammonia, and the generated washing water containing free ammonia can be used as washing water by a heavy alkali filter or used in other ways.

After the first fluidization gas G1 is classified through steps S1031 to S1034, that is, the fluidization gas output after the first fluidization gas G1 passes through the dust removal washing device is the second fluidization gas G2, the temperature of the second fluidization gas G2 is about 25 ℃, and the second fluidization gas G2 includes gas CO₂；

Compared with the embodiment 4, the embodiment of the present invention is provided with the discharging device 6, that is, one more step S10311 is provided than the embodiment, that is, the discharging device 6 processes the dry ammonium chloride B generated by the dryer 2 and the solid ammonium chloride C generated by the dry dust removing device 31 to generate the dry ammonium chloride B, and transmits part of the dry ammonium chloride B to the feed mixing device 5, and in the feed mixing device 5, the wet ammonium chloride cake a and the dry ammonium chloride B are fully mixed to generate the wet ammonium chloride. The effect of fully utilizing the dry ammonium chloride B is achieved.

In practical application, CO₂As the gas flow for drying ammonium chloride, a large amount of fluidizing gas and a sufficient pressure are required for drying and closed cycle, and fluidized bed drying of ammonium chloride requires a large amount of fluidizing gas and a sufficient pressure, a pressurizing device 7 such as a blower is often used in the prior art to increase CO₂The pressure of the gas flow, but the blower once fails, the whole process is stopped, reducing the working efficiency. Therefore, in an embodiment of the present invention, before the heating device 1 heats the CO2 rich gas F, the pressure of the CO2 rich gas F is 0.05-0.15 MPa, and the CO2 rich gas F with the pressure generates CO after the CO2 rich gas F passes through the heating device 1₂The pressure intensity of the fluidizing gas is enough to meet the requirements of drying and closed circulation, and the drying of the ammonium chloride fluidized bed needs a large amount of fluidizing gas and enough pressure, so that a pressurizing device 7 such as a blower is not needed to be additionally arranged, the condition that the blower stops working due to the fault of the blower when the pressurizing device 7 such as the blower is adopted is avoided, and the working efficiency is improved.

Specifically, the CO2 concentrated gas F is CO2 concentrated gas F discharged from a synthetic ammonia plant. The pressure of the CO2 concentrated gas F discharged from the synthetic ammonia plant is 0.1MPa, so that the pressure is higher, and the CO2 concentrated gas F with the pressure generates CO after passing through the heating device 1₂The pressure of the fluidizing gas is enough to meet the requirements of drying and closed circulation, and the fluidized bed drying of the ammonium chloride needs a large amount of fluidizing gas and enough pressure, so that a pressurizing device 7 such as a blower is not needed to be additionally arranged, and the large amount of fluidizing gas is needed for drying the ammonium chloride, thereby effectively utilizing CO2 concentrated gas F discharged by the synthetic ammonia plant, and reducing the pollution of the synthetic ammonia plant to the environment.

Alternatively, the dryer 2 includes: a fluidized bed or tubular air flow dryer 2 with a built-in heat exchanger.

Optionally, the compression carbonization apparatus comprises: a compressor disposed downstream of the dust-removing washing device 3, the compressor compressing the second fluidizing gas G2 to produce compressed carbon dioxide; and a carbonator disposed downstream of the compressor, the carbonator reacting the compressed carbon dioxide with an ammoniacal brine H to produce a heavy base.

Example 6:

fig. 11 shows a combined apparatus for drying ammonium chloride and carbonizing heavy alkali by using concentrated CO2 gas according to an embodiment of the present invention, including: a feed mixing device 5, a dryer 2 arranged at the downstream of the feed mixing device 5, a heating device 1 arranged at the upstream of the dryer 2, a discharging device 6 arranged at the downstream of the dryer 2 and a dry dust removing device 31, wherein the discharging device 6 is also arranged at the downstream of the dry dust removing device 31, a dechlorination washing tower 321 arranged at the downstream of the dry dust removing device 31, an ammonia removal condenser 322 arranged at the downstream of the dechlorination washing tower 321 and a compression carbonization device arranged at the downstream of the ammonia removal condenser 322; wherein the dryer 2 comprises a fluidized bed with a built-in heat exchanger. The compression carbonization apparatus includes: a compressor disposed downstream of the dust-removing washing device 3, the compressor compressing the second fluidizing gas G2 to produce compressed carbon dioxide; and a carbonator disposed downstream of the compressor, the carbonator reacting the compressed carbon dioxide with an ammoniacal brine H to produce a heavy base.

Fig. 12 is a schematic flow chart of a combined process for drying ammonium chloride and carbonizing heavy alkali by using a concentrated CO2 gas by using the combined apparatus for drying ammonium chloride and carbonizing heavy alkali by using a concentrated CO2 gas shown in fig. 9, and in combination with fig. 11 and 12, the combined process for drying ammonium chloride and carbonizing heavy alkali by using a concentrated CO2 gas comprises the following steps:

Step S10322: the first fluidizing gas G1 washed by the dechlorination washing tower 321 is input into the ammonia-removing condenser 322 for washing to generate condensate D1 containing free ammonia, and the discharge speed of the condensate D1 containing free ammonia is 3.2m³The concentration of ammonia is the titer (approx. pure)137kg/h of ammonia), the condensate D1 containing free ammonia can be recycled by an ammonia still and further enters a combined alkali process system as water supplement, and the temperature of the first fluidization gas G1 after passing through the ammonia removal washing tower 323 is about 25 ℃.

After the first fluidization gas G1 is classified through steps S1031 to S1033, that is, the fluidization gas output after the first fluidization gas G1 passes through the dust-removing and washing device is the second fluidization gas G2, the temperature of the second fluidization gas G2 is about 25 ℃, and the second fluidization gas G2 includes the gas CO₂；

The second fluidizing gas G2 is fed to a compressor after the compressed carbonization device, which feeds CO₂The fluidizing gas (i.e. the second fluidizing gas G2) was compressed to 0.4mpa G and then sent to a carbonizer to react with ammonia brine H to produce the heavy base (sodium bicarbonate crystals). Excess CO₂The gas may be vented at a high point prior to the compressor.

Comparative example 1:

instead of using the CO2 concentrated gas F from the ammonia synthesis plant as fluidizing gas, the CO2 concentrated gas F was used directly to compress the carbonization device, while the ammonium chloride drying was a closed cycle.

Fig. 13 is a schematic structural diagram of a combined ammonium chloride drying and carbonizing heavy alkali making apparatus in the prior art, and in combination with fig. 13, the combined ammonium chloride drying and carbonizing heavy alkali making apparatus comprises:

a feed mixing device 5, a dryer 2 arranged at the downstream of the feed mixing device 5, a heating device 1 arranged at the upstream of the dryer 2, a pressurizing device 7 (such as a blower) arranged at the upstream of the heating device 1, a discharging device 6 arranged at the downstream of the dryer 2 and a dry dust removing device 31, wherein the discharging device 6 is also arranged at the downstream of the dry dust removing device 31, a dechlorination washing tower 321 arranged at the downstream of the dry dust removing device 31, an ammonia removal condenser 322 arranged at the downstream of the dechlorination washing tower 321, and an ammonia removal washing tower 323 arranged at the downstream of the ammonia removal condenser 322, wherein the outlet end of the ammonia removal washing tower 323 is connected with the input end of the pressurizing device 7; wherein the dryer 2 comprises a fluidized bed with a built-in heat exchanger. A compression carbonization apparatus, the compression carbonization apparatus comprising: a compressor disposed downstream of the dust-removing washing device 3, the compressor compressing the second fluidizing gas G2 to produce compressed carbon dioxide; and a carbonator disposed downstream of the compressor, the carbonator reacting the compressed carbon dioxide with an ammoniacal brine H to produce a heavy base.

The combined process for preparing the heavy alkali by drying the ammonium chloride and carbonizing the ammonium chloride comprises the following steps:

the wet ammonium chloride filter cake A52000kg/h containing 6 wt% of water from upstream passes through a feeding mixing device 5, is mixed with 13000kg/h of returned dry ammonium chloride and then enters a dryer 2, hot circulating gas from a heating device 1 is added into the dryer 2 from the bottom at 190 ℃, meanwhile, heating steam is introduced into a heat exchanger arranged in the dryer 2, the circulating gas discharged from the top of the dryer 2 is about 80 ℃, and enters a chlorine removal washing tower 32132 after most of solid ammonium chloride C is removed by a dry dust removal device 31, and the chlorine removal washing tower 321 is circularly sprayed by a circulating pump and a circulating cooler. The exhaust temperature at the top of the dechlorination washing tower 321 is about 50 ℃, the ammonium chloride content of the washing water discharged from the tower bottom of the dechlorination washing tower 321 is about 3.2kg/h, and the discharged washing water is about 63 kg/h. The circulating gas entering the ammonia removal condenser 322 is cooled and condensed, the temperature of the circulating gas discharged by the ammonia removal condenser 322 is 25 ℃, condensate containing free ammonia at the bottom of the ammonia removal condenser 322 is D13.2m3/h, the ammonia concentration is 50 titer (about 137kg/h of pure ammonia), and the condensate can be used as water supplement to enter the combined alkali process system after ammonia is recovered by an ammonia still. The ammonia removal washing column 323 is not provided in this embodiment. The recycle gas 35000Nm3/h discharged from the ammonia removal condenser 322 was pressurized to 0.03MPaG by the blower 7, heated to 190 deg.C by the heating device 14, and then sent to the dryer 22 again.

The concentrated gas F (0.1 MPaG) of CO2 from the synthetic ammonia plant is directly sent to a compression carbonization device to be compressed to 0.4MPaG and then sent to a carbonization tower to react with ammonia brine H to generate heavy alkali.

Comparative example 2:

comparative example No CO2 concentrate F from the ammonia synthesis plant was used as fluidizing gas, but the CO2 concentrate F was used directly in the compression carbonization unit, and ammonium chloride drying was performed as a closed cycle, but the ammonia and chlorine removal of the recycle gas was not carried out as a staged scrubbing.

Fig. 14 is a schematic structural diagram of a combined ammonium chloride drying and carbonizing heavy alkali manufacturing apparatus in the prior art, which includes:

a feed mixing device 5, a dryer 2 arranged downstream of the feed mixing device 5, a heating device 1 arranged upstream of the dryer 2, a pressurizing device 7 (such as a blower) arranged upstream of the heating device 1, a discharging device 6 arranged downstream of the dryer 2, and a dry dust removal device 31, wherein the discharging device 6 is also arranged downstream of the dry dust removal device 31, and an ammonia removal washing tower 323 arranged downstream of the dry dust removal device 31, wherein the outlet end of the ammonia removal washing tower 323 is connected with the input end of the pressurizing device 7; wherein the dryer 2 comprises a fluidized bed with a built-in heat exchanger. A compression carbonization apparatus, the compression carbonization apparatus comprising: a compressor disposed downstream of the dust-removing washing device 3, the compressor compressing the second fluidizing gas G2 to produce compressed carbon dioxide; and a carbonator disposed downstream of the compressor, the carbonator reacting the compressed carbon dioxide with an ammoniacal brine H to produce a heavy base.

the wet ammonium chloride cake containing 6% wt of water A52000kg/h from upstream was passed through a feed mixing device 5, and mixed with returned dry ammonium chloride B13000kg/h and then enters a dryer 2, hot circulating gas from a heating device 1 is added into the dryer 22 from the bottom at 190 ℃, meanwhile, heating steam is introduced into a heat exchanger arranged in the dryer 2, the circulating gas discharged from the top of the dryer 2 is about 80 ℃, most of solid ammonium chloride C is removed by dry dust removal equipment 31, the ammonia-removing washing water enters an ammonia-removing washing tower 323 to remove residual ammonium chloride and ammonia gas, 3m3/h of fresh washing water is added to the top of the ammonia-removing washing tower 323, the content of ammonium chloride in the washing water at the bottom of the ammonia-removing washing tower 323 is about 3.2kg/h, the ammonia concentration is 24 titer (the content of pure ammonia is about 137kg/h), the discharged washing water is about 6.2m3/h, and the part of the washing water cannot be effectively used as make-up water to enter a combined alkali process system due to the fact that the part of the washing water contains ammonium chloride. The recycle gas 35000Nm3/h discharged from the ammonia removal scrubber 323 is pressurized to 0.03MPaG by the blower 7, heated to 190 ℃ by the heating device 14, and sent to the dryer 22 again.

CO2 concentrated gas F (0.1 MPaG) from a synthetic ammonia plant is directly sent to a compression carbonization device to be compressed to 0.4MPaG and then sent to a carbonization tower to react with ammonia brine H to generate heavy alkali.

Comparative example 3:

in the third comparative example, the concentrated CO2 gas from the ammonia synthesis plant is not used as the fluidizing gas, but the concentrated CO2 gas is directly used in the compression carbonization device, and the ammonium chloride drying is the traditional open air drying.

Fig. 15 is a schematic structural diagram of a combined ammonium chloride drying and carbonizing heavy alkali manufacturing apparatus in the prior art, which includes:

a feed mixing device 5, a dryer 2 arranged downstream of the feed mixing device 5, a heating device 1 arranged upstream of the dryer 2, a first pressure device 71 (such as a blower) arranged upstream of the heating device 1, a discharge device 6 arranged downstream of the dryer 2, and a dry dust removal device 31, wherein the discharge device 6 is also arranged downstream of the dry dust removal device 31, an ammonia removal scrubber 323 arranged downstream of the dry dust removal device 31, and a second pressure device 72 arranged downstream of the ammonia removal scrubber 323, wherein an outlet end of the ammonia removal scrubber 323 is connected with an input end of the second pressure device 72; wherein the dryer 2 comprises a fluidized bed with a built-in heat exchanger. A compression carbonization apparatus, the compression carbonization apparatus comprising: a compressor disposed downstream of the dust-removing washing device 3, the compressor compressing the second fluidizing gas G2 to produce compressed carbon dioxide; and a carbonator disposed downstream of the compressor, the carbonator reacting the compressed carbon dioxide with an ammoniacal brine H to produce a heavy base.

the wet ammonium chloride filter cake A52000kg/h containing 6 wt% of water from the upstream passes through a feeding mixing device 5 and is mixed with returned dry ammonium chloride B13000kg/h and then enters a dryer 2, fresh air is pressurized to 0.025MPaG by a blower 7 and then is sent to a heating device 1 to be heated to 190 ℃ and then is added into the dryer 2 from the bottom, meanwhile, heating steam is introduced into a heat exchanger arranged in the dryer 2, the circulating gas discharged from the top of the dryer 2 is about 80 ℃, after most of solid ammonium chloride C is removed by a dry dust removal device 31, residual ammonium chloride and ammonia gas are removed from the ammonia removal washing tower 323, fresh washing water with the volume of 100m3/h is added to the top of the ammonia removal washing tower 323, the washing water at the bottom of the ammonia removal washing tower 323 contains about 3.2kg/h of ammonium chloride, the ammonia concentration is about 1.4 titer (about 137kg/h of pure ammonia), the discharged washing water is about 103.2m3/h, the part of the washing water contains ammonium chloride and has huge volume, can not effectively be used as water supplement to enter the combined alkali process system. The tail gas 35000Nm3/h discharged from the ammonia removal scrubber 32334 was pressurized to 0.001MPaG by the blower 7 and then discharged to the atmosphere.

Example 6 of the present invention and comparative examples 1, 2 and 3 were compared for process parameters and economic reasons as shown in the following table:

wherein, in the table above:

1. consumption of fresh water includes water recovered from wet ammonium chloride filter cake a and washing added fresh water;

2. the electricity cost is 0.5 yuan/degree, the fresh water cost is 0.6 yuan/ton, and the ammonia cost is 3000 yuan/ton.

3. The annual operating costs represent the sum of the total electricity costs of the pressurizing means 7, for example a blower, and a compressor, the costs of fresh water and the costs of saving ammonia.

4. The minus sign in the table indicates the meaning of saving.

As can be seen from the above table, the operation cost per year is the same as that of comparative example 1 by using example 5, but the blast pressurization device 7 is arranged in the comparative example 1, and the pressurization device 7 is not arranged in the example 6, so that the pressure of the concentrated CO2 gas F is completely relied on, the stability is high, and the stop caused by the failure of the blower is avoided.

With comparative example 2, no staged chlorine removal and ammonia removal was performed, and the annual fresh water cost and ammonia loss cost was 333.312 ten thousand yuan greater, although the electricity cost was the same as in example 6.

By adopting the comparative example 3 and adopting a large amount of fresh water for washing, the ammonia content of the tail gas exhausted to the atmosphere still reaches 1185mg/Nm3 which is far beyond the environmental protection emission standard. Besides 817.536 ten thousand per year of electricity, the additional cost for treating the 103.2m3/h wastewater containing chlorine and ammonia is considered.

The invention has been described in terms of a specific embodiment of a combined process for producing heavy alkali by ammonium chloride drying and carbonization directly using CO2 concentrated gas from an ammonia synthesis plant. The invention can be used for various purposes, such as the modification of process equipment types, equipment combinations, processing methods, parameters, and the like, which can be performed by a person skilled in the art without departing from the spirit and principle of the invention.

Claims

1. By using CO₂The integrated unit that concentrated gas carries out ammonium chloride drying and carbonization system heavy alkali, its characterized in that includes:

a heating device for heating CO₂Heating the concentrated gas to produce CO₂Fluidizing gas, wherein;

and the second fluidizing gas output by the dedusting and washing device is input into the carbon compression device, and the carbon compression device mixes the second fluidizing gas with the ammonia brine to generate the heavy alkali.

2. The utilization of CO of claim 1₂A combined device for drying ammonium chloride and carbonizing concentrated gas to prepare heavy alkali, which is characterized in that,

the dust removal washing device includes: a dry dedusting apparatus disposed downstream of the dryer, the dry dedusting apparatus configured to dedust the first fluidizing gas to produce solid ammonium chloride; and a wet scrubbing apparatus disposed downstream of the dry dedusting apparatus, the wet scrubbing apparatus configured to progressively scrub the first fluidization gas to produce a staged ammonium chloride scrubbing water and a liquid containing free ammonia.

3. The utilization of CO of claim 2₂Combined installation for drying ammonium chloride and carbonizing heavy alkali from concentrated gas, characterized in that the wet scrubbing plant comprises:

4. The utilization of CO of claim 3₂The combined device for drying ammonium chloride and carbonizing concentrated gas to prepare heavy alkali is characterized in thatIn that the wet scrubbing apparatus further comprises:

5. The utilization of CO of claim 1₂A combined device for drying ammonium chloride and carbonizing concentrated gas to prepare heavy alkali, which is characterized in that,

the compression carbonization apparatus includes: a compressor disposed downstream of said dust removal scrubbing apparatus, said compressor compressing said second fluidizing gas to produce compressed carbon dioxide; and a carbonator disposed downstream of the compressor, the carbonator reacting the compressed carbon dioxide with an ammonia brine to produce a heavy base; and/or

6. The utilization of CO of claim 1₂The integrated unit that the dense gas carries out ammonium chloride drying and carbonization system heavy alkali, its characterized in that still includes:

7. By using CO₂The combined process for preparing the heavy alkali by drying and carbonizing ammonium chloride in concentrated gas is characterized by comprising the following steps of:

introducing CO₂Dense gasInputting the mixture into a heating device for heating to generate CO₂Fluidizing gas, wherein said CO₂The pressure of the concentrated gas is 0.05-0.15 MPa;

mixing the second fluidizing gas with ammonia brine in a compressed carbonization device to produce heavy alkali;

preferably, the CO is₂The concentrated gas is CO discharged from a synthetic ammonia plant₂And (4) concentrating.

8. The utilization of CO of claim 7₂The combined process of drying ammonium chloride and carbonizing concentrated gas to prepare heavy alkali is characterized in that the dust removal washing device comprises a dry dust removal device arranged at the downstream of the dryer and a wet washing device arranged at the downstream of the dry dust removal device;

9. The utilization of CO of claim 8₂The combined process of drying ammonium chloride and carbonizing concentrated gas to prepare heavy alkali is characterized in that the wet type washing equipment comprises a chlorine removal washing tower arranged at the downstream of the dry type dust removal equipment and an ammonia removal condenser arranged at the downstream of the chlorine removal washing tower;

10. Utilizing CO according to claim 9₂The combined process of drying ammonium chloride and carbonizing concentrated gas to prepare heavy alkali is characterized in that the wet type washing equipment further comprises an ammonia removal washing tower arranged at the downstream of the ammonia removal condenser;

preferably, the first and second liquid crystal materials are,

at the time of the introduction of the CO₂The fluidized gas is introduced into the dryer from the bottom of the dryer, and the wet ammonium chloride is introduced into the dryer by using CO₂Drying ammonium chloride and carbonizing to prepare heavy productAn integrated process for a base, further comprising:

preferably, the first and second liquid crystal materials are,

inputting the dry ammonium chloride to the feed mixing device.