Waste ammonia purification system and method

Abstract

According to the waste ammonia purification system and the waste ammonia purification method, centralized treatment is conducted at a waste ammonia source, waste ammonia is converted into clean ammonia, value can be effectively added, the purified ammonia is convenient for a user to use at ease, a decontamination unit does not need to be considered any more, social investment is reduced, energy consumption is extremely low, meanwhile, the temperature of liquid ammonia in a waste ammonia tank can be controlled, volatilization of low-boiling-point components can be controlled, and the waste ammonia purification system is suitable for industrial production. And the content of low-boiling-point impurities in the clean ammonia is reduced. The system comprises a dirty liquid ammonia buffer tank, an ammonia gas compressor, a liquid ammonia circulating pump, a circulating cooler, a cleaning liquid liquid ammonia buffer tank, a water cooler and a circulating heater, dirty liquid ammonia in the dirty liquid ammonia buffer tank is conveyed by a liquid ammonia circulating pump, heated and circulated by a circulating cooler and a circulating heater, and returns to the dirty liquid ammonia buffer tank for circulation; gas-phase ammonia in the dirty liquid ammonia buffer tank is compressed and heated by an ammonia gas compressor, then is conveyed to a water cooler for cooling, is further cooled by low-temperature dirty liquid ammonia through a circulating cooler, and is cooled and condensed into clean liquid ammonia to be conveyed to the clean liquid ammonia buffer tank.

Description

Technical Field

[0001] The present invention relates to the technical field of waste ammonia purification, and in particular to a waste ammonia purification system and method. Background Art

[0002] Currently, the petrochemical industry produces a lot of liquid ammonia as a by-product, which contains various impurities, affecting the use of liquid ammonia as a standard chemical raw material. Therefore, in the process of recycling and reusing liquid ammonia containing impurities, purification equipment is usually required to purify the liquid ammonia.

[0003] At present, when purifying waste ammonia in the market, the liquid ammonia containing impurities condensed and separated from the tail gas of industrial equipment is generally exported as a by-product, and each transferee handles it by themselves. However, there is a lack of suitable special processing equipment for waste ammonia purification. In addition, due to the uneven technical levels of the owners and different effects, the investment in processing equipment is large and uneconomical, resulting in low export value of by-products and little profit for the source enterprises. Therefore, a waste ammonia purification system and method are proposed to solve the above problems. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a system and method for purifying waste ammonia, which has the advantages of improving the treatment effect while reducing treatment investment and lowering operating costs, thereby solving the problem of poor purification treatment effect and large treatment investment.

[0005] To achieve the above object, the present invention provides the following technical solutions: a dirty ammonia purification system and method, comprising a dirty liquid ammonia buffer tank, an ammonia compressor, a liquid ammonia circulation pump, a circulation cooler, a clean liquid ammonia buffer tank, an ammonia condenser, and a circulation heater;

[0006] The dirty liquid ammonia in the dirty liquid ammonia buffer tank is transported by a liquid ammonia circulation pump, heated in turn by a circulation cooler and a circulation heater, and then returned to the dirty liquid ammonia buffer tank for continuous circulation; the clean gaseous ammonia in the dirty liquid ammonia buffer tank is compressed and heated by an ammonia compressor, and then sent to an ammonia condenser for condensation, and then further cooled by the low-temperature dirty liquid ammonia in the dirty liquid ammonia circulation cooler, and then cooled and condensed by itself to become clean liquid ammonia and sent to the clean liquid ammonia buffer tank.

[0007] Furthermore, the liquid inlet end of the dirty liquid ammonia buffer tank is the dirty ammonia delivery end, and the output end of the clean liquid ammonia buffer tank is the clean ammonia delivery end.

[0008] Furthermore, the dirty liquid ammonia buffer tank, the ammonia compressor, the circulating cooler, the clean liquid ammonia buffer tank and the ammonia condenser are located on the gas ammonia delivery pipeline and are interconnected through the gas ammonia delivery pipeline.

[0009] Furthermore, the dirty liquid ammonia buffer tank, the liquid ammonia circulation pump, the circulation cooler and the circulation heater are located on the dirty liquid ammonia circulation pipeline and are interconnected through the dirty liquid ammonia circulation pipeline.

[0010] Furthermore, the ammonia condenser and the circulation heater are also located on the circulating cooling water pipeline to achieve condensation of clean ammonia and heating of dirty liquid ammonia. The input end of the ammonia condenser is the circulating cooling input end, and the output end of the circulation heater is the circulating cooling water output end.

[0011] A method for purifying polluted ammonia comprises the following steps:

[0012] S1, after the dirty ammonia is sent into the dirty liquid ammonia buffer tank 1, the clean liquid ammonia buffer tank 5 is first evacuated to remove the non-condensable gas, and then the gas phase pressure of the balance tank 1 and tank 5 is equal, and then the ammonia compressor 2 is started to compress the clean gas ammonia in the dirty ammonia tank gas phase, and the compressed and heated gas ammonia is sent to the ammonia condenser 6 to condense into clean liquid ammonia, and finally the dirty liquid ammonia after cooling is sent to the circulating cooler 4 by the liquid ammonia circulating pump 3 for further cooling, and the gas phase ammonia is cooled and condensed to obtain pure liquid ammonia and sent to the clean liquid ammonia buffer tank 5 for storage;

[0013] S2, the dirty liquid ammonia with relatively low temperature is sent to the circulating cooler 4 through the circulating liquid ammonia pump 3, and is heated by the waste heat of the clean liquid condensed by the ammonia condenser 6, and then enters the circulating heater 7 to be further heated by the heated circulating cooling water sent by the ammonia condenser 6 to increase the temperature of the dirty ammonia, and after returning to the dirty liquid ammonia buffer tank 1, it continues to be gasified due to the suction, pressure reduction and temperature reduction of the compressor. This treatment process is very energy-saving;

[0014] S3, the circulating cooling water first enters the ammonia condenser 6 to condense the high-temperature gaseous ammonia sent by the ammonia compressor 2, and then the heated circulating cooling water is sent to the circulating heater 7 to further heat the dirty ammonia, providing the heat required for the gasification of the dirty liquid ammonia buffer tank.

[0015] Compared with the prior art, the technical solution of this application has the following beneficial effects:

[0016] 1. The system and method for purifying polluted ammonia do not generate new pollution sources during the entire purification process. A small amount of ammonia is discharged during system maintenance and overhaul, and regular sewage discharge from the polluted ammonia tank. A small amount of ammonia water is obtained through ammonia recovery and purification and can be sold as a by-product. The tail gas meets the emission standards, and there is no problem of excessive sewage discharge during the production process. Purified ammonia can effectively increase the value, which is convenient for users to use with confidence, without having to consider the decontamination unit, and reducing social investment.

[0017] 2. The system and method for purifying contaminated ammonia do not require external heat sources during the entire process. The contaminated ammonia can be pumped to circulate and recycle the compression heat of gaseous ammonia and the sensible heat of circulating cooling water. The pressure or temperature of the contaminated ammonia tank can be controlled at appropriate indicators to reduce the volatilization of low-boiling-point components and the content of low-boiling-point impurities in clean ammonia. The entire purification equipment can be integrated through ammonia compressors, liquid ammonia circulation pumps, circulation coolers, ammonia condensers, circulation heaters and other equipment, thus realizing the purification production from the entire process of collection, purification and storage. The equipment usage is small, and the entire system DCS / PLC is fully automated, unmanned, and the production conditions are extremely simple to maintain. Only the compressor and pump need to be overhauled and the wearing parts replaced as planned. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0019] In the figure: 1. Dirty liquid ammonia buffer tank; 2. Ammonia compressor; 3. Liquid ammonia circulation pump; 4. Circulation cooler; 5. Clean liquid ammonia buffer tank; 6. Ammonia condenser; 7. Circulation heater. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] See also Figure 1 , a dirty ammonia purification system in this embodiment includes a dirty liquid ammonia buffer tank 1, an ammonia compressor 2, a delivery pump 3, a circulating cooler 4, a clean liquid ammonia buffer tank 5, a water cooler 6, and a circulating heater 7;

[0022] The dirty liquid ammonia in the dirty liquid ammonia buffer tank 1 is transported by the liquid ammonia circulation pump 3, and is heated by the circulation cooler 4 and the circulation heater 7 to return to the dirty liquid ammonia buffer tank 1 for circulation; the gaseous ammonia in the dirty liquid ammonia buffer tank 1 is compressed and heated by the ammonia compressor 2, and then sent to the water cooler 6 for cooling, and then further cooled by the low-temperature dirty liquid ammonia through the dirty liquid ammonia circulation cooler 4, and then cooled and condensed by itself to become clean liquid ammonia and sent to the clean liquid ammonia buffer tank 5.

[0023] Among them, the liquid inlet end of the dirty liquid ammonia buffer tank 1 is the dirty ammonia delivery end, and the output end of the clean liquid ammonia buffer tank 5 is the clean ammonia delivery end. The dirty liquid ammonia buffer tank 1 collects and stores dirty liquid ammonia, and the clean liquid ammonia buffer tank 5 collects and stores clean liquid ammonia.

[0024] In addition, the dirty liquid ammonia buffer tank 1, the ammonia compressor 2, the circulating cooler 4, the clean liquid ammonia buffer tank 5 and the cooler 6 are located on the gas ammonia delivery pipeline and are interconnected through the gas ammonia delivery pipeline. The dirty liquid ammonia buffer tank 1, the ammonia compressor 2, the circulating cooler 4, the clean liquid ammonia buffer tank 5 and the cooler 6 form a flow channel for the entire gas ammonia to process the gas ammonia.

[0025] Secondly, the dirty liquid ammonia buffer tank 1, the delivery pump 3, the circulation cooler 4 and the circulation heater 7 are located on the dirty liquid ammonia circulation pipeline, and are interconnected through the dirty liquid ammonia circulation pipeline. The dirty liquid ammonia buffer tank 1, the delivery pump 3, the circulation cooler 4 and the circulation heater 7 form a dirty ammonia treatment channel to treat the dirty ammonia flowing through.

[0026] Finally, the cooler 6 and the circulating heater 7 are also located on the circulating cooling water pipeline and are interconnected through the circulating cooling water pipeline. The input end of the cooler 6 is the circulating cooling input end, and the output end of the circulating heater 7 is the circulating cooling water output end.

[0027] In this embodiment, the entire process does not require consumption of external heat sources. It is sufficient to pump the waste ammonia circulation to recover the compression heat of gaseous ammonia and the sensible heat of circulating cooling water. The volatilization of low-boiling-point components is controlled, and the pressure or temperature of the waste ammonia tank is controlled at appropriate indicators, which can reduce the content of low-boiling-point impurities in clean ammonia. The entire purification equipment can be integrated together through an ammonia compressor, a liquid ammonia circulation pump, a circulation cooler, an ammonia condenser, a circulation heater and other equipment, thereby realizing the purification production of the entire process from collection, pure water, and storage. The equipment usage is small, and the entire system DCS / PLC is fully automated, realizing unmanned operation, and the maintenance of production conditions is extremely simple. Only the compressor and pump need to be overhauled and the wearing parts replaced as planned.

[0028] It should be noted that: 1) the present invention can be operated by only external power supply to drive the ammonia compressor and the waste ammonia circulation pump, and the energy consumption of waste ammonia purification is extremely low;

[0029] 2) All equipment is operated at room temperature, and the equipment does not require professional insulation or cooling;

[0030] 3) The production and purification process only requires 2 operating devices, and a total of 7 devices can be completed;

[0031] 4)PLC control, fully automatic and unattended operation.

[0032] In this embodiment, a method for purifying polluted ammonia comprises the following steps:

[0033] S1, after the dirty ammonia is sent into the dirty liquid ammonia buffer tank 1, the clean liquid ammonia buffer tank 5 is first evacuated to remove the non-condensable gas, and then the gas phase pressure of the balance tank 1 and tank 5 is equal, and then the ammonia compressor 2 is started to compress the clean gas ammonia in the dirty ammonia tank gas phase, and the compressed and heated gas ammonia is sent to the ammonia condenser 6 to condense into clean liquid ammonia, and finally the dirty liquid ammonia after cooling is sent to the circulating cooler 4 by the liquid ammonia circulating pump 3 for further cooling, and the gas phase ammonia is cooled and condensed to obtain pure liquid ammonia and sent to the clean liquid ammonia buffer tank 5 for storage;

[0034] S2, the dirty liquid ammonia with relatively low temperature is sent to the circulating cooler 4 through the circulating liquid ammonia pump 3, and is heated by the waste heat of the clean liquid condensed by the ammonia condenser 6, and then enters the circulating heater 7 to be further heated by the heated circulating cooling water sent by the ammonia condenser 6 to increase the temperature of the dirty ammonia, and after returning to the dirty liquid ammonia buffer tank 1, it continues to be gasified due to the suction, pressure reduction and temperature reduction of the compressor. This treatment process is very energy-saving;

[0035] S3, the circulating cooling water first enters the ammonia condenser 6 to condense the high-temperature gaseous ammonia sent by the ammonia compressor 2, and then the heated circulating cooling water is sent to the circulating heater 7 to further heat the dirty ammonia, providing the heat required for the gasification of the dirty liquid ammonia buffer tank.

[0036] In this embodiment, the method has extremely low energy consumption and can transfer ammonia in dirty ammonia into clean liquid ammonia under normal temperature conditions, which is higher than the national standard for first-class industrial liquid ammonia. At the same time, the energy consumption comes from the power consumption of the ammonia compressor, and the production capacity is restricted by the delivery capacity of the compressor.

[0037] The working principle of the above embodiment is:

[0038] The dirty ammonia in the dirty liquid ammonia buffer tank 1 is sent to the circulating cooler 4 by the liquid ammonia pump 3, and after being heated by the circulating cooler 4, it is sent to the dirty liquid ammonia buffer tank 1 for storage and circulation heating. The gaseous ammonia in the dirty liquid ammonia buffer tank 1 after being heated is compressed by the ammonia compressor 2, and the compressed and heated gaseous ammonia is sent to the cooler 6 for cooling, and then continuously sent to the circulating cooler 4 for further circulation cooling. The cooled and liquefied clean liquid ammonia flows into the clean liquid ammonia buffer tank 5 for storage and transportation.

[0039] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0040] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A dirty ammonia purification system, comprising a dirty liquid ammonia buffer tank (1), an ammonia compressor (2), a liquid ammonia circulation pump (3), a circulation cooler (4), a clean liquid ammonia buffer tank (5), an ammonia condenser (6), and a circulation heater (7); Features: The dirty liquid ammonia in the dirty liquid ammonia buffer tank (1) is transported by the liquid ammonia circulation pump (3) through the circulation cooler (4) and the circulation heater (7) to return to the dirty liquid ammonia buffer tank (1) for circulation, and the liquid ammonia condensed by the ammonia condenser (6) is cooled in turn, and the circulating dirty liquid ammonia is heated by cooling water in the circulation heater (7); the gaseous ammonia in the dirty liquid ammonia buffer tank (1) is compressed and heated by the ammonia compressor (2) and then sent to the ammonia condenser (6) for cooling, and then further cooled by the circulating low-temperature dirty liquid ammonia through the circulation cooler (4), and becomes clean liquid ammonia and is sent to the clean liquid ammonia buffer tank (5).

2. A waste ammonia purification system according to claim 1, characterized in that: The liquid inlet end of the dirty liquid ammonia buffer tank (1) is the dirty ammonia delivery end, and the output end of the clean liquid ammonia buffer tank (5) is the clean ammonia delivery end.

3. A waste ammonia purification system according to claim 1, characterized in that: The dirty liquid ammonia buffer tank (1), the ammonia compressor (2), the circulating cooler (4), the clean liquid ammonia buffer tank (5) and the ammonia condenser (6) are located on the gas ammonia delivery pipeline and are interconnected via the gas ammonia delivery pipeline.

4. A waste ammonia purification system according to claim 1, characterized in that: The dirty liquid ammonia buffer tank (1), the liquid ammonia circulation pump (3), the circulation cooler (4) and the circulation heater (7) are located on the dirty liquid ammonia circulation pipeline and are interconnected via the dirty liquid ammonia circulation pipeline.

5. A waste ammonia purification system according to claim 1, characterized in that: The ammonia condenser (6) and the circulation heater (7) are also located on a circulation cooling water pipeline and are interconnected through the circulation cooling water pipeline; the input end of the ammonia condenser (6) is a circulation cooling input end, and the output end of the circulation heater (7) is a circulation cooling water output end.

6. A method for purifying polluted ammonia, characterized in that: The following steps are involved: S1, after the dirty ammonia is sent to the dirty liquid ammonia buffer tank (1), the clean liquid ammonia buffer tank (5) is first evacuated to remove the non-condensable gas, and then the gas phase pressures of the balance tank (1) and tank (5) are equal, and then the ammonia compressor (2) is started to compress the clean gaseous ammonia in the dirty ammonia tank gas phase, and the compressed and heated gaseous ammonia is sent to the ammonia condenser (6) to condense into clean liquid ammonia, and finally the dirty liquid ammonia after cooling is sent to the circulating cooler (4) by the liquid ammonia circulating pump (3) for further cooling, and the gaseous ammonia is cooled and condensed to obtain pure liquid ammonia and sent to the clean liquid ammonia buffer tank (5) for storage; S2, the dirty liquid ammonia at a relatively low temperature is sent to the circulating cooler (4) through the circulating liquid ammonia pump (3), and is heated by the waste heat of the clean liquid condensed by the ammonia condenser (6), and then enters the circulating heater (7) to be further heated by the heated circulating cooling water sent by the ammonia condenser (6) to raise the temperature of the dirty ammonia, and after returning to the dirty liquid ammonia buffer tank (1), it continues to be gasified due to the suction, pressure reduction and temperature reduction of the compressor. This treatment process is very energy-saving; S3, the circulating cooling water first enters the ammonia condenser (6) to condense the high-temperature gaseous ammonia sent by the ammonia compressor (2), and then the heated circulating cooling water is sent to the circulating heater (7) to further heat the dirty ammonia, providing the heat required for the reaction of the dirty liquid ammonia buffer tank for gasification.

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