METHOD FOR PREPARING AMMONIA BY USING AMMONIUM SALT AND SILICATE

Abstract

Disclosed is a method for preparing ammonia gas through a reaction between an ammonium salt and a silicate. An aqueous solution of the ammonium salt in the form of atomized droplets is contacted with a silicate at a high temperature for a reaction to generate ammonia gas and a solid substance. The silicate can be solid particles, and forms a bed. The generated ammonia gas is collected, the solid substance is extracted, part of the same solid substance is mixed with a fresh silicate solid particle, and the mixture continuously reacts with the atomized droplets of the aqueous solution of the ammonium salt.

Claims

1. A method for preparing ammonia gas through a reaction between an ammonium salt and a silicate, wherein preparing ammonia gas through a reaction between an ammonium salt aqueous solution and a silicate at a high temperature.

2. The method according to claim 1, comprising following steps: contacting the ammonium salt aqueous solution in form of atomized droplets with the silicate at a high temperature in form of solid particle in a reactor, so that a reaction occurs on surfaces of a silicate solid particle to generate the ammonia gas and a solid substance; collecting the ammonia gas obtained by the reaction to obtain an ammonia gas product; and extracting a part of the solid substance, and mixing the part of the same solid substance with a fresh silicate solid particle, then returning a mixture to the reactor, and continuously reacting with the atomized droplets of the ammonium salt aqueous solution.

3. The method according to claim 1, wherein the silicate is a salt formed by a silicate radical and an alkali metal or an alkaline earth metal; and the ammonium salt is a salt formed by an ammonium radical and an acid radical of a strong acid.

4. The method according to claim 1, wherein a temperature of the silicate is 80 to 600 DEG C.

5. The method according to claim 1, wherein the ammonium salt aqueous solution is a saturated ammonium salt aqueous solution.

6. The method according to claim 1, wherein a ratio of the amount of substance of the ammonium salt to the amount of substance of the silicate is 1:2-1:6.

7. The method according to claim 2, wherein a mass ratio of the amount of the solid substance extracting from the reactor to the amount of the solid substance recycling to the reactor is 1:2-1:8.

8. The method according to any one of claim 2, wherein the reactor is a moving bed reactor or a fluidized bed reactor.

9. The method according to claim 2, wherein the silicate solid particle is the solid particle containing one or more of calcium silicate, magnesium silicate, sodium silicate and potassium silicate; a source of the silicate solid particle comprises: pulverizing and grinding of an ore containing the silicate as well as a plurality of silicate crystal particle obtained through chemical synthesis methods; and the ammonium salt is one or more of ammonium chloride, ammonium sulfide or ammonium hydrogen sulfate.

10. The according to claim 4, wherein the temperature of the silicate at a high temperature in form of solid particle is 200 to 450 DEG C.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Through description on the embodiments of the present disclosure by the following reference drawings, the above and other aims, characteristics and advantages of the present disclosure are clearer.

[0029] FIG. 1 is a process flow diagram of the present disclosure;

[0030] FIG. 2 is a schematic diagram of an embodiment 1 of the present disclosure for preparing ammonia gas by using a fluidized bed;

[0031] FIG. 3 is a schematic diagram of an embodiment 2 of the present disclosure for preparing ammonia gas by using a moving bed.

DESCRIPTION OF DRAWING LABELS

[0032] Embodiment 1: 10—fluidized bed reactor; 11—gas and solid separation device; 12—preheater; 13—gas distributor; 14—high-pressure liquefying pump; 15—solid feeding device; 16—nozzle.

[0033] Embodiment 2: 20—deflection baffle; 21—moving bed reactor; 22—heating coiled pipe; 23—high-pressure liquefying pump; 24—nozzle; 25—solid feeding device.

DESCRIPTION OF THE EMBODIMENTS

[0034] The present disclosure is described in detail below with reference to the drawings. For clarity, each part of the drawings is not drawn to scale. In addition, some known parts may not be shown.

[0035] Many specific details of the present disclosure are described below to understand the present disclosure more clearly. However, the disclosure may be practiced without these specific details, as will be understood by those skilled in the art. The chemical reaction to which the present disclosure relates is as follows:

2NH.sub.4.sup.++SiO.sub.3.sup.2−.fwdarw.SiO.sub.2+2NH.sub.3↑+H.sub.2O (in the presence of water)

[0036] FIG. 1 is a process flow diagram of the present disclosure, in which an atomized 31 ammonium salt aqueous solution 30 is contacted with a silicate solid particle 33 at a high temperature in the reactor 32 to perform reaction to generate a solid substance 34 and an ammonia gas 35; the solid substance 34 is extracted, and part of the solid substance is circulated, to be mixed with the fresh silicate solid particle 33 for entering the reactor 32 and is contacted with the atomized 31 ammonium salt aqueous solution 30 to perform reaction to complete a circulation.

[0037] The silicate solid particle of the present disclosure is a solid particle containing one or more of calcium silicate, magnesium silicate, sodium silicate and potassium silicate; the ammonium salt is one or more of ammonium chloride, ammonium sulfate and ammonium hydrogen sulfate.

Embodiment 1

[0038] FIG. 2 is a schematic diagram of the embodiment 1 of the present disclosure for preparing the ammonia gas by using the fluidized bed, in which a certain amount of particulate silicate raw materials enter a fluidized bed reactor 10 through a solid feeding device 15, the aqueous solution of the ammonium salt are in the form of atomized droplets under the action of a high-pressure liquefying pump 14 and a nozzle 16 and are contacted with the silicate particle to perform reaction to generate the solid substance and the ammonia gas; the solid substance is extracted, and part of the solid substance is circulated to be mixed with the fresh silicate particle; then, the ammonia gas and a water vapor are escaped along with a carrier gas to enter a gas and solid separation device 11, and part of the separated gas phase containing the ammonia gas is led out, one part of which is circulated to be mixed with a fresh carrier gas for entering a moving bed reactor 10 through a gas distributor 13 after being preheated by a preheater 12.

[0039] As a specific embodiment, the total volume of the fluidized bed reactor used in the present embodiment is 10 L, with a height-diameter ratio of 5:1, that is, the reactor is 0.136 m in diameter and 0.69 m in height; the present embodiment employs serpentine with the magnesium silicate content of 86 percent as the solid particle, in which the average particle size of the particle is 0.8 mm; the ammonium salt adopts ammonium sulfate, and a molar ratio of the ammonium sulfate to the magnesium sulfate in the reaction process is 1:4.

[0040] With an air serves as the carrier gas and an operation performed under a normal pressure, the air is preheated to 500 DEG C in the preheater, wherein the hot air rate is 15.4 m3/h (under the standard condition), the working temperature of the reactor is controlled to 350 DEG C, the temperature of the ammonium sulfate solution is 90 DEG C, the mass percentage is 43.6 percent, and the spray quantity is 1 kg/h; then, 50 percent of circulation quantity of the outlet waste gas is adjusted, so that the ratio of the extraction quantity of the solid substance to the use amount of the solid substance returning to the reactor is 1:7.5 (mass ratio), the supplementing quantity of the serpentine particle is 0.18 kg/h, obtaining results as shown in Table 1:

TABLE-US-00001 TABLE 1 Results of reaction in the 10 L fluidized bed reactor Material Magnesium Ammonia sulfate gas Flow/kg/h 0.177 0.05 Conversion rate (%) 89.1 of ammonium sulfate Conversion rate (%) 95.4 of magnesium silicate

Embodiment 2

[0041] FIG. 3 is a schematic diagram of preparing the ammonia gas by using a moving bed in Embodiment 2, a certain amount of particulate silicate raw materials enter a moving bed reactor 21 through a solid feeding device 25 and perform a bending movement under the action of a deflection baffle 21; a high-temperature medium supplies heat for the system through a heating coiled pipe 22, and the aqueous solution of the ammonium salt are in the form of atomized droplets under the action of a high-pressure liquefying pump 23 and a nozzle 24 and are contacted with the silicate particle to perform reaction to generate the solid substance and the ammonia gas, in which the ammonia gas is led out, the solid substance is extracted, and part of the solid substance is circulated to be mixed with the fresh silicate particle.

[0042] As a specific embodiment, the total volume of the moving bed reactor used in the present embodiment is 10 L, with a height-diameter ratio of 20:1, that is, the reactor is 0.086 m in diameter and 1.72 m in height; an atomizing nozzle and a heating coiled pipe are arranged below each deflection baffle (not all shown in figure), the embodiment employs serpentine with a magnesium silicate content of 86 percent as the solid particle, wherein the average particle size of the particle is 0.8 mm; the ammonium salt adopts ammonium sulfate. The molar ratio of the ammonium sulfate to the magnesium silicate is 1:4, the working temperature of the reactor is controlled to 350 DEG C, the high-temperature medium is a heat-conducting oil, the temperature of the ammonium sulfate solution is 90 DEG C, the mass percentage is 43.6 percent, the spray quantity is 1 kg/h, the ratio of the extraction quantity of the solid substance to the use amount of the solid substance returning to the reactor is 1:7.5 (mass ratio), and the supplementing quantity of the serpentine particle is 0.18 kg/h, obtaining results as shown in Table 2:

TABLE-US-00002 TABLE 2 Results of reaction in the 10 L moving bed reactor Material Magnesium Ammonia sulfate gas Flow/kg/h 0.159 0.045 Conversion rate (%) 80.2 of ammonium sulfate Conversion rate (%) 85.8 of magnesium silicate

Embodiment 3

[0043] Equipment and process flow used in the present embodiment are as same as those in Embodiment 1 except in that the present embodiment employs aedelforsite with a calcium silicate content of 85 percent as the solid particle, wherein the average particle size of the particle is 0.8 mm, and the ammonium salt adopts the ammonium chloride. The molar ratio of the ammonium chloride to the calcium silicate is 1:2; with an air serves as the carrier gas and an operation performed under a normal pressure, the air is preheated to 450 DEG C in the preheater, wherein the hot air rate is 15.4 m3/h (under the standard condition), the working temperature of the reactor is controlled to 300 DEG C, the temperature of the ammonium chloride solution is 90 DEG C, the mass percentage is 40.8 percent, and the spray quantity is 0.3 kg/h; 50 percent of circulation quantity of the outlet waste gas is adjusted, so that the ratio of the extraction quantity of the solid substance to the use amount of the solid substance returning to the reactor is 1:4 (mass ratio), and the supplementing quantity of the aedelforsite particle is 0.14 kg/h, obtaining reaction results as shown in Table 3:

TABLE-US-00003 TABLE 3 Results of the reaction of the ammonium chloride and the aedelforsite in the 10 L fluidized bed reactor Material Calcium Ammonia chloride gas Flow/kg/h 0.108 0.033 Conversion rate (%) 79.4 of ammonium chloride Conversion rate (%) 94.7 of calcium silicate

Embodiment 4

[0044] Equipment and process flow used in the present embodiment are as same as those in Embodiment 2 except in that the present embodiment employs aedelforsite with a calcium silicate content of 85 percent as the solid particle, wherein the average particle size of the particle is 0.8 mm, and the ammonium salt adopts the ammonium chloride. The molar ratio of the ammonium chloride to the calcium silicate is 1:2, the working temperature of the reactor is controlled to 300 DEG C, the high-temperature medium is heat-conducting oil, the temperature of the ammonium chloride solution is 90 DEG C, the mass percentage is 40.8 percent, and the spray quantity is 0.3 kg/h; 50 percent of the circulating quantity of the outlet waste gas is adjusted, so that the ratio of the extraction quantity of the solid substance to the use amount of the solid substance returning to the reactor is 1:4 (mass ratio), and the supplementing quantity of the aedelforsite particle is 0.14 kg/h, obtaining reaction results as shown in Table 4:

TABLE-US-00004 TABLE 4 Results of the reaction of the ammonium chloride and the aedelforsite in the 10 L moving bed reactor Material Calcium Ammonia chloride gas Flow/kg/h 0.098 0.03 Conversion rate (%) 72.2 of ammonium chloride Conversion rate (%) 86.1 of calcium silicate

Embodiment 5

[0045] Equipment and process flow used in the present embodiment are as same as those in Embodiment 3 except in that the working temperature of the fluidized beds of the embodiment is controlled to 200 DEG C, 250 DEG C, 400 DEG C and 450 DEG C, and the reaction results are as shown in Table 5:

TABLE-US-00005 TABLE 5 Results of the reaction of the ammonium chloride and the aedelforsite in the 10 L fluidized bed reactor temperature 200 250 400 450 Conversion 72.2 74.6 81.8 80.6 rate (%) of ammonium chloride Conversion 86.1 89 97.6 96.2 rate (%) of calcium silicate

[0046] It can be seen from the above embodiments, under the same condition, the conversion rate is higher when the disclosure adopts the fluidized bed.

[0047] It should be noted that, according to the common knowledge of those skilled in the art, corresponding measuring devices, control devices and corresponding valves for temperature, liquid level and the like are arranged on the decomposition reactor and the regeneration reactor, which are not shown in the drawings one by one. This does not indicate that these conventional designs are not included in the process of the present disclosure. Adjusting the feed rate of the raw materials in the present disclosure according to the conversion rate and the material balance is also a conventional design common knowledge of those skilled in the art, and there is no description in the present disclosure, and this does not indicate that the conventional design is not included in the process of the present disclosure.

[0048] According to the embodiments of the present disclosure described above, the embodiments do not describe all the details in detail, and the present disclosure is not limited to the specific embodiments. Obviously, many modifications and changes can be made according to the above description. The description selects and specifically describes the embodiments to explain the principle and the actual application of the present disclosure well, so that those skilled in the art can utilize the present disclosure well, and perform modification and use on the basis of the present disclosure.