Methods For Extracting And Recycling Ammonia From MOCVD Process Exhaust Gas By FTrPSA

Abstract

The present invention discloses methods for extracting and recycling ammonia in MOCVD processes by FTrPSA. Through pretreatment, medium-shallow temperature PSA concentration, condensation and freezing, liquid ammonia vaporization, PSA ammonia extraction, and ammonia gas purification procedures, ammonia-containing exhaust gases from MOCVD processes are purified to meet the electronic-level ammonia gas standard required by the MOCVD processes, so as to implement recycling and reuse of the exhaust gases, where the ammonia gas yield is greater than or equal to 70-85%. The present invention solves the technical problem that atmospheric-pressure or low-pressure ammonia-containing exhaust gases in MOCVD processes cannot be returned to the MOCVD processes for use after being recycled, and fills the gap in green and circular economy development of the LED industry.

Claims

1. A method for extracting and recycling ammonia from an MOCVD process exhaust gas by FTrPSA (full temperature range-pressure swing adsorption), comprising following procedures: 1) preparing a feed gas, i.e., an exhaust gas in a MOCVD manufacturing process for a light emitting diode based on gallium nitride epitaxial wafer growth, the feed gas being at atmospheric pressure or low pressure and at temperature of 20-140 C.; 2) executing pretreatment procedure: wherein introducing the feed gas into a pretreatment unit to remove catcher, dust, particles, oil mist and other impurities in sequence under operating conditions that a pressure is 0.2-0.3 MPa and a temperature is 20-140 C.; 3) executing medium-shallow temperature PSA (pressure swing adsorption) concentration: wherein compressing the feed gas from the pretreatment procedure to 0.3-4.0 MPa, entering a multi-tower PSA concentration equipment with an operating pressure of 1.0-4.0 MPa and an operating temperature of 20-140 C., at least one of adsorption towers of the multi-tower PSA concentration equipment is in an adsorption step and a formed adsorbed phase gas is an ammonia-rich concentrated gas; 4) executing condensation and freezing procedure: wherein introducing the ammonia-rich concentrated gas into a condensation and freezing equipment to form liquid ammonia; 5) executing liquid ammonia vaporization procedure: wherein introducing the liquid ammonia into a liquid ammonia vaporization equipment to form an industrial ammonia gas; 6) executing PSA ammonia extraction procedure: wherein introducing industrial ammonia gas from the liquid ammonia vaporization procedure into a multi-tower PSA ammonia gas purification equipment with an operating pressure of 0.6-2.0 MPa and an operating temperature of 60-120 C., at least one of adsorption towers of the multi-tower PSA ammonia gas purification equipment is in the adsorption step, the remaining adsorption towers are in the desorption and regeneration step, and a formed non-adsorbed phase gas is an ultra-pure ammonia gas; and 7) executing ammonia gas purification procedure: wherein decompressing the ultra-pure ammonia gas to a pressure required by the ammonia gas used in a light-emitting diode MOCVD process, entering an ammonia gas purification equipment with an operating temperature of 60-500 C. and an operating pressure ranging from the atmospheric pressure to a pressure condition required by the ammonia gas in the MOCVD process, removing trace impurities to obtain a final electronic-level ammonia gas product.

2. The method for extracting and recycling ammonia from a MOCVD process exhaust gas by FTrPSA according to claim 1, wherein the feed gas mainly consisting of nitrogen, hydrogen, and ammonia, as well as a small quantity of metal ions, particles, arsine, methane, water, carbon monoxide, carbon dioxide, oxygen and other impurity components.

3. The method for extracting and recycling ammonia from a MOCVD process exhaust gas by FTrPSA according to claim 2, wherein the feed gas further comprises a waste gas or a tail gas main components of which comprise hydrogen gas, nitrogen gas, ammonia gas and other impurity components generated in other remaining semiconductor processes.

4. The method for extracting and recycling ammonia from a MOCVD process exhaust gas by FTrPSA according to claim 1, wherein the pretreatment unit comprises a dust remover, a particle removing filter and an oil mist removing catcher.

5. The method for extracting and recycling ammonia from a MOCVD process exhaust gas by FTrPSA according to claim 4, wherein in the pretreatment procedure, in a working condition that the feed gas is a waste gas or a tail gas containing high concentrations of other impurity components, a caustic scrubber, a neutralizing tower and a dryer are additionally provided to remove acidic and volatile organic matters and other impurity components.

6. The method for extracting and recycling ammonia from a MOCVD process exhaust gas by FTrPSA according to claim 1, wherein the remaining adsorption towers are in a desorption and regeneration step, and a formed non-adsorbed phase gas is an adsorption exhaust gas, which is introduced into a hydrogen extraction process, or is treated by means of catalytic combustion or spraying to meet the national standards for atmospheric control and be directly discharged.

7. The method for extracting and recycling ammonia from a MOCVD process exhaust gas by FTrPSA according to claim 1, wherein an adsorbent used in the medium-shallow temperature PSA concentration procedure is one or a combination of activated aluminum oxide, silica gel, activated carbon and a molecular sieve.

8. The method for extracting and recycling ammonia from a MOCVD process exhaust gas by FTrPSA according to claim 1, wherein in the adsorption tower adsorption step of the medium-shallow temperature PSA concentration procedure, after the adsorption tower desorption step ends and before a pressure equalizing dropping or normal flowing step starts, an ultra-pure ammonia gas from the PSA ammonia extraction procedure is used for replacement, for improving the yield of the ammonia gas in this procedure to be 80-90% or higher.

9. The method for extracting and recycling ammonia from a MOCVD process exhaust gas by FTrPSA according to claim 1, wherein in the medium-shallow temperature PSA concentration, the feed gas from the pretreatment procedure is pressurized to 0.2-0.3 MPa by the blower and enters from a bottom of a first-stage PSA adsorption tower, the non-adsorbed phase adsorption exhaust gas flows out of a first-stage PSA tower top to be treated and the desorbed gas desorbed at and flowing out of a first-stage PSA tower bottom is fed to a bottom of a second-stage PSA adsorption tower by means of the blower, a non-adsorbed phase mixed intermediate gas flows out of a second-stage PSA tower top and returns as a first-stage PSA feed gas for further recycling ammonia, and the ammonia-rich concentrated gas flowing out of a second-stage PSA tower bottom enters the condensation and freezing procedure.

10. The method for extracting and recycling ammonia from a MOCVD process exhaust gas by FTrPSA according to claim 9, wherein by means of blowing or pressurization, after the adsorption step ends and before the pressure equalizing dropping or normal flowing step starts, a replacement step is added in the second PSA adsorption tower, in which the ultra-pure ammonia gas from the PSA ammonia extraction procedure is used as a replacement gas, for improving the yield of the ammonia gas in this procedure to be 80-90% or higher.

11. The method for extracting and recycling ammonia from a MOCVD process exhaust gas by FTrPSA according to claim 1, wherein in the medium-shallow temperature PSA concentration, the feed gas from the pretreatment procedure is pressurized to 0.3-4.0 MPa, the feed gas enters a bottom of a first-stage PSA adsorption tower, and a non-adsorbed phase intermediate gas flows out of the first-stage PSA tower top; a part of the non-adsorbed phase intermediate gas serves as a feed gas to a bottom of a second-stage PSA adsorption tower, and the other part serves as the adsorption waste gas to be treated; the desorbed gas desorbed at and flowing out of the first-stage PSA tower bottom is fed to the condensation and freezing procedure; the feed gas from the pretreatment procedure is pressurized to 0.3-4.0 MPa by means of a compressor and then mixed with a part of the intermediate gas flowing out of the first-stage PSA tower top, serves as a feed gas to the second PSA adsorption tower, and then is fed to the second-stage PSA adsorption tower bottom, and the non-adsorbed phase intermediate gas flows out of the second-stage PSA tower top; a part of the non-adsorbed phase intermediate gas serves as a feed gas to the bottom of the first PSA adsorption tower, and the other part serves as the adsorption waste gas to be treated, the desorbed gas desorbed at and flowing out of the second-stage PSA tower bottom is mixed with the desorbed gas desorbed at and flowing out of the first-stage PSA tower bottom, and is then fed to the condensation and freezing procedure.

12. The method for extracting and recycling ammonia from a MOCVD process exhaust gas by FTrPSA according to claim 11, wherein after the adsorption step ends and before the pressure equalizing dropping or normal flowing step starts, a replacement step is added in the first and second-stage PSA adsorption towers, in which the ultra-pure ammonia gas from the PSA ammonia extraction procedure is used as a replacement gas, for improving the yield of the ammonia gas in this procedure to be 80-90% or higher, or the desorbed gas flowing from this procedure is used as the replacement gas after being compressed, for improving the yield of the ammonia gas in this procedure to be 80-90% or higher.

13. The method for extracting and recycling ammonia from a MOCVD process exhaust gas by FTrPSA according to claim 1, wherein a non-condensable gas produced in the condensation and freezing procedure is mixed with the feed gas for further ammonia recycling, or is mixed with the adsorption exhaust gas in the medium-shallow temperature PSA concentration procedure, or is introduced to the hydrogen extraction process, or is treated by means of catalytic combustion, spraying to meet the national emission standards for atmospheric control and directly discharged.

14. The method for extracting and recycling ammonia from a MOCVD process exhaust gas by FTrPSA according to claim 1, wherein the PSA ammonia extraction procedure, vacuum pumping and purging are adopted in the desorption and regeneration mode, the formed desorbed gas is directly exhausted to a waste steam treatment system outside the area for treatment, and an adsorbent used in the PSA ammonia extraction procedure is one or a combination of activated aluminum oxide, silica gel, activated carbon, and a molecular sieve.

15. The method for extracting and recycling ammonia from a MOCVD process exhaust gas by FTrPSA according to claim 1, wherein an ammonia gas rectification procedure is used to replace the condensation and freezing procedure, the operating temperature of the ammonia gas rectification procedure is 70-140 C. and the operating pressure is 0.3-2.0 MPa; an impurity component having a boiling point higher than that of the ammonia flows out of a bottom of the rectification tower and is fed outside the area for treatment.

16. The method for extracting and recycling ammonia from a MOCVD process exhaust gas by FTrPSA according to claim 15, wherein the ammonia-rich concentrated gas from the medium-shallow temperature PSA concentration procedure enters a condenser by means of blowing or pressurization to form the liquid ammonia, and then enters the ammonia gas rectification equipment; the ammonia gas flows out of a top of a rectification tower of the ammonia gas rectification equipment, and a part of the ammonia gas returns to the condenser for reflux; the other non-condensable gas escapes from the condenser, and returns to the raw gas, or is mixed with the adsorption waste gas flowing out of the medium-shallow temperature PSA concentration procedure, or is introduced into a hydrogen extraction process, or is treated by means of catalytic combustion, spraying to meet the national emission standards for atmospheric control and be directly discharged; a part of the ammonia has a concentration greater than or equal to 99%, and directly enters the PSA ammonia extraction procedure.

17. The method for extracting and recycling ammonia from a MOCVD process exhaust gas by FTrPSA according to claim 1, wherein the PSA ammonia extraction procedure, the ammonia gas is added with metal palladium as a catalytic deaerator for removing oxygen in a working condition containing a small amount of oxygen, the operating temperature is 70-90 C., and the depth reaches 0.1 ppm or lower; and the oxygen-removed ammonia gas enters PSA ammonia extraction.

18. The method for extracting and recycling ammonia from a MOCVD process exhaust gas by FTrPSA according to claim 1, wherein the liquid ammonia formed in the condensation and freezing procedure and having an ammonia concentration greater than or equal to 98-99% directly enters a liquid phase adsorption procedure; under a temperature ranging from 40 C. to 40 C. and at pressure ranging from the atmospheric pressure to 4.0 MPa, the liquid ammonia enters, from a tower top of a temperature-pressure swing adsorption tower consisting of two or three towers, and is subjected to liquid phase adsorption at the adsorption temperature ranging from 40 C. to 40 C. and at the adsorption pressure ranging from the atmospheric pressure to 4.0 MPa; a small amount of water and other adsorption impurity components serve as adsorbates and are adsorbed by the adsorbent with which the adsorption tower is filled; the ammonia, as the non-adsorbed phase which is non-absorbable, is made into the liquid ammonia having a purity of 99.999%, flows out of the bottom of the adsorption tower as a product output, and then fed to ammonia gas purification.

19. The method for extracting and recycling ammonia from a MOCVD process exhaust gas by FTrPSA according to claim 18, wherein the adsorbed small amount of water and other adsorption impurity components serve as the adsorbed phase, are subjected to regeneration of a thermal regeneration gas and desorption by rinsing at the atmospheric pressure or by vacuum pumping and purging, and then exhausted from the top of the adsorption tower; when one adsorption tower allows the liquid ammonia having the purity of 99.999% to flow out after the adsorption ends, another adsorption tower enters the liquid phase adsorption procedure again after thermal regeneration and desorption, thereby achieving a continuous cyclic adsorption operation; when three towers are working, one tower performs adsorption, one performs regeneration, and the remaining one stands by or performs regeneration.

20. The method for extracting and recycling ammonia from a MOCVD process exhaust gas by FTrPSA according to claim 1, wherein in the medium-shallow temperature PSA concentration procedure and the PSA ammonia extraction procedure, under an operating condition that the adsorption pressure is greater than or equal to 0.6 MPa, slow and uniform control is implemented on pressure changes in a cyclic operation process of adsorption and desorption by means of a program control valve and a regulating valve on pipelines connected between the adsorption towers.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0041] FIG. 1 is a schematic flowchart of embodiment 1 of the present invention.

[0042] FIG. 2 is a schematic flowchart of embodiment 5 of the present invention.

[0043] FIG. 3 is a schematic flowchart of embodiment 6 of the present invention.

[0044] FIG. 4 is a schematic flowchart of embodiment 7 of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0045] In order to make a person skilled in the art better understand the present invention, the technical solutions in the embodiments of the present invention are clearly and fully described below with reference to the accompanying drawings in the embodiments of the present invention.

[0046] As shown in FIG. 1, a method for extracting and recycling ammonia from an MOCVD process exhaust gas by FTrPSA includes the following specific implementation steps:

[0047] (1) a raw gas, i.e., an exhaust gas in a manufacturing process for an LED based on gallium nitride epitaxial wafer growth which is prepared by MOCVD at atmospheric pressure or low pressure, the feed gas mainly consisting of 46% (v/v, the same below) of nitrogen (N2), 34% of hydrogen (H2), and 19% of ammonia (NH3), and the remaining 1% being a small quantity of metal ions, particles, arsine, methane (CH4), water (H2O), carbon monoxide (CO), carbon dioxide (CO2), and oxygen (O2), and other impurity components, the pressure being atmospheric pressure or low pressure, and the temperature being 50-70 C.;

[0048] (2) pretreatment: introducing the feed gas into a pretreatment unit consisting of a dust remover, a particle removing filter, and an oil mist removing catcher, removing dust, particles, oil mist, and other impurities in sequence under operating conditions that the pressure is 0.2-0.3 MPa and the temperature is 50-70 C., and proceeding to a next procedure, i.e., a medium-shallow temperature PSA concentration procedure;

[0049] (3) medium-shallow temperature PSA concentration: compressing the feed gas from the pretreatment procedure to 1.6 MPa, entering a multi-tower PSA concentration procedure consisting of six towers, where the operating pressure of the adsorption towers is 1.6 MPa, the operating temperature is 50-70 C., one-tower adsorption, secondary pressure equalizing, a slow and uniform mode, and desorption and regeneration by vacuum pumping and purging are used, and a formed non-adsorbed phase gas is an adsorption exhaust gas, which has an NH3 concentration controlled to be below or equal to 0.5% and is treated by means of catalytic combustion and spraying to meet the national emission standards for atmospheric control and be directly discharged; a formed adsorbed phase gas is an ammonia-rich concentrated gas, which has an ammonia concentration of 65% and is compressed to 0.6 MPa and then enters a next procedure, i.e., a condensation and freezing procedure; an adsorbent used in the medium-shallow temperature PSA concentration procedure is a composite combination of activated aluminum oxide, silica gel, activated carbon, and a molecular sieve;

[0050] (4) condensation and freezing: compressing the ammonia-rich concentrated gas from the medium-shallow temperature PSA concentration procedure to 0.5-0.6 MPa, enabling the gas to enter a condensation and freezing procedure consisting of a condenser, an evaporator condenser, and a freezer to form liquid ammonia having an ammonia concentration greater than or equal to 98-99%, and proceeding to a next procedure, i.e., ammonia vaporization, where a non-condensable gas produced in the condensation and freezing procedure is mixed with the adsorption exhaust gas in the medium-shallow temperature PSA concentration procedure, and then is treated by means of catalytic combustion and spraying to meet the national emission standards for atmospheric control and directly discharged;

[0051] (5) liquid ammonia vaporization: directly introducing the liquid ammonia from the condensation and freezing procedure to a liquid ammonia vaporization procedure for vaporization, the liquid ammonia vaporization procedure consisting of a liquid ammonia evaporator and an ammonia gas buffer tank, so as to form an ammonia gas having an ammonia concentration greater than or equal to 98-99% (industrial ammonia), and proceeding to a next procedure, i.e., an ammonia gas purification procedure;

[0052] (6) PSA ammonia extraction: directly introducing industrial ammonia from the liquid ammonia vaporization procedure to a multi-tower PSA ammonia gas purification procedure consisting of six adsorption towers, where the operating pressure of the adsorption towers is 0.5-0.6 MPa, the operating temperature is 50-70 C., one-tower adsorption, secondary pressure equalizing, a slow and uniform mode, and desorption and regeneration by vacuum pumping and purging are used, and a formed non-adsorbed phase gas is an ultra-pure ammonia gas with a purity greater than or equal to 99.995%, and proceeding to a next procedure, i.e., ammonia gas purification, where the formed desorbed gas is directly exhausted to a waste steam treatment system outside the area for treatment, and an adsorbent used in the PSA ammonia extraction procedure is a composite combination of activated aluminum oxide, silica gel, activated carbon, and a molecular sieve; and

[0053] (7) ammonia gas purification: enabling the ultra-pure ammonia gas from the PSA ammonia extraction procedure to pass through an intermediate product storage tank, then heating the ultra-pure ammonia gas to 300-400 C. by means of heat exchange, adjusting the pressure to a pressure required by the ammonia gas used in an LED MOCVD process, which is 0.3 MPa in the present embodiment, entering an ammonia gas purification procedure consisting of a metal getter purifier, purifying at the operating temperature of 300-400 C. and under the operating pressure of 0.3 MPa, removing trace impurities to obtain a final electronic-level ammonia gas product, the purity of which satisfies an electronic-level ammonia gas (white ammonia) product standard specified by the state or the SEMI, the purity of the ammonia gas being greater than or equal to 99.99999-99.999999% (level 7-8N), reducing the temperature to the normal temperature by means of heat exchange, and introducing the final product to an electronic-level ammonia gas product storage tank for storage, and making the final product enter the MOCVD process according to the requirements on the ammonia gas in use during the process, where the operating temperature of the ammonia gas purification procedure is determined by the used metal getter, a high-temperature metal getter is used in the present embodiment, the temperature is 300-400 C., the service life of the getter is at least longer than two years, and no regeneration is needed; in this way, the yield of the obtained electronic-level ammonia gas product is greater than 70-86%.

Embodiment 2

[0054] As shown in FIG. 1, on the basis of embodiment 1, under a condition that the temperature of the feed gas is below 20-30 C. and other conditions are not changed, heat exchange is performed between the high temperature product gas generated in the ammonia gas purification procedure and the raw gas, and after the temperature is recovered to 50-70 C., operations are carried out as specified in embodiment 1. The purpose is to prevent a high concentration of ammonia in the feed gas from escaping at a temperature lower than the ambient temperature 20 C. and becoming a liquid, which may damage the equipment in the pretreatment procedure.

Embodiment 3

[0055] As shown in FIG. 1, on the basis of embodiment 1, under a condition that the temperature of the feed gas is below 100-120 C. and other conditions are not changed, the operations in embodiment 1 are directly and normally carried out, where the pretreated feed gas is pressurized to 3.0 MPa, the operating pressure of the medium-shallow temperature PSA concentration procedure is 3.0 MPa, and the operating temperature is 100-120 C.; the adsorption waste gas from the medium-shallow temperature PSA concentration procedure and the non-condensable gas from the condensation and freezing procedure are mixed and first fed to a spraying step for recycling some ammonia water, then enter catalytic combustion and spraying treatment to meet the national emission standards for atmospheric control and be directly discharged; the ammonia-rich concentrated gas from the medium-shallow temperature PSA concentration procedure enters the condensation and freezing procedure.

Embodiment 4

[0056] As shown in FIG. 1, on the basis of embodiment 1, during the medium-shallow temperature PSA concentration, in the adsorption tower desorption step, after the adsorption tower adsorption step ends and before a normal flowing step starts, the ultra-pure ammonia gas from the PSA ammonia extraction procedure is used for replacement, for improving the yield of the ammonia gas in this procedure to be 80-90% or higher.

Embodiment 5

[0057] As shown in FIG. 2, on the basis of embodiment 1, in the medium-shallow temperature PSA concentration, the feed gas from the pretreatment procedure is fed to the medium-shallow temperature PSA concentration by the blower without being compressed; the procedure is composed of two stages of PSA systems; that is, the feed gas from the pretreatment procedure is pressurized to 0.2-0.3 MPa by the blower and enters from the bottom of a first PSA adsorption tower (first-stage PSA), the non-adsorbed phase adsorption exhaust gas flows out of a first-stage PSA tower top, where the NH3 concentration is controlled to be lower than or equal to 0.5%, and the exhaust gas is treated by means of catalytic combustion and spraying to meet the national emission standards for atmospheric control and be directly discharged; the desorbed gas desorbed (reverse flowing, purging, or vacuum pumping) at and flowing out of a first-stage PSA tower bottom is fed to the bottom of a second PSA adsorption tower (second-stage PSA) by means of the blower, a non-adsorbed phase mixed intermediate gas flows out of a second-stage PSA tower top and returns as a first-stage PSA feed gas for further recycling ammonia, and the ammonia-rich concentrated gas having a concentration higher than or equal to 65-70% and flowing out of a second-stage PSA tower bottom enters the next procedure, i.e., the condensation and freezing procedure, by means of blowing or pressurization, where after the adsorption step ends and before the pressure equalizing dropping or normal flowing step starts, a replacement step is added in the second PSA adsorption tower (second-stage PSA), in which the ultra-pure ammonia gas from the PSA ammonia extraction procedure is used as a replacement gas, for improving the yield of the ammonia gas in this procedure to be 80-90% or higher.

Embodiment 6

[0058] As shown in FIG. 3, on the basis of embodiment 1, in the medium-shallow temperature PSA concentration, the feed gas from the pretreatment procedure is pressurized to 1.6 MPa and then mixed with some intermediate gas flowing out of the first-stage PSA tower top; the mixture serves as the feed gas to the second PSA adsorption tower (second-stage PSA) and is fed from the tower bottom; the non-adsorbed phase intermediate gas flows out of the second-stage PSA tower top, a part of the non-adsorbed phase intermediate gas serves as a feed gas to the bottom of the first-stage PSA adsorption tower, and the other part serves as the adsorption waste gas, which is treated by means of catalytic combustion and spraying to meet the national emission standards for atmospheric control and be directly discharged; the desorbed gas (the ammonia-rich concentrated gas) desorbed (reverse flowing, purging, or vacuum pumping) at and flowing out of the second-stage PSA tower bottom is mixed with the desorbed gas (the ammonia-rich concentrated gas) desorbed at and flowing out of the first-stage PSA tower bottom, and the mixture is fed to the next procedure, i.e., the condensation and freezing procedure, by means of the blower, where after the adsorption step ends and before the pressure equalizing dropping or normal flowing step starts, a replacement step is added in the first and the second PSA adsorption towers, in which the desorbed gas (the ammonia-rich concentrated gas) flowing from the present procedure is pressurized and then used as a replacement gas, for improving the yield of the ammonia gas in this procedure to be 80-90% or higher.

Embodiment 7

[0059] As shown in FIG. 4, on the basis of embodiment 1, the liquid ammonia formed in the condensation and freezing procedure and having an ammonia concentration greater than or equal to 98-99% directly enters the liquid phase adsorption procedure; under a temperature ranging from 40 C. to 40 C. and at pressure of 0.6-1.6 MPa, the liquid ammonia enters, from the tower top, a TPSA tower consisting of two towers, and is subjected to liquid phase adsorption at the adsorption temperature ranging from 40 C. to 40 C. and at the adsorption pressure of 0.6-1.6 MPa; a small amount of water and other adsorption impurity components serve as adsorbates and are adsorbed by the adsorbent with which the adsorption tower is filled; the ammonia, as the non-adsorbed phase which is non-absorbable, is made into the liquid ammonia having a purity of 99.999%, and flows out of the bottom of the adsorption tower as a product output, which is subjected to canned pressurized vaporization and then fed to ammonia gas purification; the adsorbed small amount of water and other adsorption impurity components serve as the adsorbed phase, are subjected to regeneration of a thermal regeneration carrier gas (steam) and desorption by vacuum pumping and purging, and then exhausted from the top of the adsorption tower; one adsorption tower allows the liquid ammonia having the purity of 99.999% to flow out after the adsorption ends, and the other adsorption tower enters the liquid phase adsorption procedure again after thermal regeneration and desorption, thereby achieving a continuous cyclic adsorption operation.

[0060] Obviously, the above-mentioned embodiment is only part of the embodiment in the present invention rather than the whole embodiment. Based on the embodiment recorded in the present invention, with respect to all other embodiments obtained by those skilled in the art without paying creative work, or the structural changes made under the inspiration of the present invention, all technical solution that are identical or similar to the present invention fall into the protection scope of the present invention.