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CN-121988057-A - Heat pump rectification production equipment, system and process for ammonia

CN121988057ACN 121988057 ACN121988057 ACN 121988057ACN-121988057-A

Abstract

The invention discloses a heat pump rectifying device, a system and a process for ammonia, which adopt a direct self-backheating rectifying system to drive a heat pump compressor by clean electric energy, and adopt a mechanical compression mode to compress and heat light component vapor at the top of a rectifying tower as a heat source of a reboiler, thereby saving a large amount of vapor and circulating water. The system adopts a two-stage heat pump rectification mode combining staged compression and intermediate cooling, and effectively solves the problems of high single-stage compression energy consumption and overhigh exhaust temperature by reasonably distributing compression ratio, thereby realizing the remarkable reduction of the total energy consumption of the system. Meanwhile, through secondary pressure boosting, cooling and gas-liquid separation treatment, the working medium entering the reflux pump is ensured to be completely liquefied, so that the cavitation hidden danger is fundamentally eliminated, and the long-term stable operation of the rectification system is ensured.

Inventors

  • GAO ZHANGHUA
  • CAO BOTAO
  • LIU KEKE
  • WU TAO
  • TANG JIANBO

Assignees

  • 宁波萃英化学技术有限公司

Dates

Publication Date
20260508
Application Date
20260116
Priority Date
20251222

Claims (15)

  1. 1. A heat pump rectification apparatus for ammonia, characterized by comprising a rectification unit (200) of N stages, a compression cycle unit (300); The N-level rectifying unit (200) comprises N-level rectifying modules, wherein any rectifying template comprises a rectifying tower (210) and a reboiler (220) communicated with the rectifying tower (210), a heavy component extraction outlet (211) of the rectifying tower (210) of the front rectifying module is communicated with a raw material inlet (213) of the rectifying tower (210) of the rear rectifying module for the rectifying modules of the adjacent two levels, a light component reflux outlet (212) of the rectifying tower (210) of the front rectifying module is communicated with a light component extraction outlet (214) of the rectifying tower (210) of the rear rectifying module, and the first-level rectifying module is also provided with a light component comprehensive reflux outlet (215); The compression circulation unit (300) comprises a first-stage compressor (310) and a gas-liquid separator (320), wherein a light component extraction outlet (214) of a first-stage rectification module is communicated with an inlet of the first-stage compressor (310) of the compression circulation unit (300), an outlet of the first-stage compressor (310) is communicated with an inlet of a rectification module reboiler (220), an outlet of the rectification module reboiler (220) is communicated with an inlet of the gas-liquid separator (320), and a liquid phase outlet of the gas-liquid separator (320) is communicated with a light component comprehensive reflux port (215) of the first-stage rectification module; the N-level rectifying unit (200) is a 2-10-level rectifying unit.
  2. 2. The heat pump rectification apparatus of claim 1, wherein any one of said rectification columns (210) comprises any one or more of the following (I) - (VII): (I) The heavy component extraction outlet (211) is arranged at the lower part or the bottom of the rectifying tower (210); (II) the light component reflux port (212) is arranged at the lower part or the bottom of the rectifying tower (210); (III) the feedstock inlet (213) is disposed in the middle, upper or top of the rectifying column (210); (IV) the light component extraction port (214) is provided at the upper part or the top of the rectifying tower (210); (V) a light component integrated reflux port (215) of a rectifying tower (210) of the first-stage rectifying module is arranged at the upper part or the top of the rectifying tower (210); (VI) the reboiler (220) inlet is disposed at an upper portion or top of the reboiler (220); The outlet of the reboiler (220) of (VII) is arranged at the lower part or the bottom of the reboiler (220).
  3. 3. The heat pump rectification apparatus of ammonia according to claim 1 or 2, wherein the outlet of said primary compressor (310) is in communication with the inlet of the reboiler (220) of each stage of rectification module; The outlet of the reboiler (220) of each stage of rectifying module is communicated with the inlet of the gas-liquid separator (320).
  4. 4. A heat pump rectification apparatus for ammonia according to claim 3, further comprising a raw material storage unit (100), said raw material storage unit (100) being in communication with the raw material inlet (213) of the first stage rectification module; And/or, further comprising a heavy component storage unit (400), wherein the heavy component storage unit (400) is communicated with a heavy component extraction outlet (211) of the N-th-stage rectifying module; and/or, further comprising a deuterium depleted ammonia storage unit (500), the liquid phase outlet of said gas-liquid separator (320) being in communication with deuterium depleted ammonia storage unit (500).
  5. 5. The heat pump rectification apparatus according to claim 3, wherein said compression cycle unit (300) further comprises a secondary compressor (330) and a heat exchanger (340), wherein a gas phase outlet of said gas-liquid separator (320) is in communication with an inlet of the secondary compressor (330), and an outlet of the secondary compressor (330) is in communication with a return port of the gas-liquid separator (320) through the heat exchanger (340).
  6. 6. The heat pump rectification apparatus according to claim 5, wherein said compression cycle unit (300) further comprises an expansion valve provided between the heat exchanger (340) and the return port of the gas-liquid separator (320), and a gas evacuation valve provided between the heat exchanger (340) and the expansion valve or provided at the upper part or top of the gas-liquid separator (320).
  7. 7. The heat pump distillation apparatus for ammonia according to any one of claims 1 to 2, 4 to 6, wherein the heat pump distillation apparatus for ammonia comprises any one or more of the following (a) - (e): (a) The heavy component extraction outlet (211) of the rectifying tower (210) of the front rectifying module is communicated with the raw material inlet (213) of the rectifying tower (210) of the rear rectifying module through a pump; (b) A flowmeter is arranged on a communication pipeline between a heavy component extraction outlet (211) of a rectifying tower (210) of the front rectifying module and a raw material inlet (213) of a rectifying tower (210) of the rear rectifying module; (c) The liquid phase outlet of the gas-liquid separator (320) is communicated with the light component comprehensive reflux port (215) of the first-stage rectification module through a pump; (d) A flowmeter is arranged on a communication pipeline between a liquid phase outlet of the gas-liquid separator (320) and a light component comprehensive reflux port (215) of the first-stage rectifying module; (e) The raw material storage unit (100) is communicated with a raw material inlet (213) of the first-stage rectifying module through a pump.
  8. 8. The heat pump rectification apparatus for ammonia according to any one of claims 1 to 2, 4 to 6, wherein a flow meter is provided on a communication pipe between an outlet of the primary compressor (310) and an inlet of the rectification block reboiler (220); and/or a valve and a flowmeter are arranged on the communication pipeline between the outlet of the first-stage compressor (310) and the inlet of the reboiler (220) of each rectifying module; and/or a flowmeter is arranged on a main pipeline connected with the outlet of the first-stage compressor (310).
  9. 9. The heat pump distillation apparatus for ammonia according to any one of claims 1 to 8, wherein the diameter of the rectifying tower (210) of the first stage distillation module to the rectifying tower (210) of the nth stage distillation module is gradually reduced.
  10. 10. The ammonia production system is characterized by comprising an alkaline electrolytic tank water treatment device, an ammonia water exchange device and an ammonia heat pump rectification device which are sequentially communicated; Wherein the heat pump rectification apparatus for ammonia is the heat pump rectification apparatus for ammonia according to any one of claims 1 to 10.
  11. 11. A heat pump rectification process for ammonia, comprising the steps of: S1, raw materials to be treated enter a rectifying tower (210) through a raw material inlet (213) of a first-stage rectifying module; S2, after raw materials to be treated are introduced, heavy components extracted from a rectifying tower (210) of a front rectifying module are introduced into a rectifying tower (210) of a rear rectifying module, light components extracted from the rectifying tower (210) of the rear rectifying module are returned to the rectifying tower (210) of the front rectifying module, and a final product is extracted from the rectifying tower (210) of an N-th rectifying module and then introduced into a heavy component storage unit (400) for storage; Meanwhile, light components extracted from a rectifying tower (210) of the first-stage rectifying module are pressurized and heated by a first-stage compressor (310), are led into a reboiler (220) of an N-stage rectifying unit (200) in N paths, discharged materials after heat exchange in the reboiler (220) are led into a gas-liquid separator (320) for treatment, and liquid phases extracted from the gas-liquid separator (320) are returned to the rectifying tower (210) of the first-stage rectifying module.
  12. 12. The heat pump rectification process of ammonia according to claim 11, wherein in step S2, any one or more of the following conditions (I) - (V) are satisfied: (I) Light components extracted by a rectifying tower (210) of the first-stage rectifying module are processed by a first-stage compressor (310) and then are introduced into a reboiler (220) of the N-stage rectifying module in N paths; (II) discharging after heat exchange in the reboiler (220) is introduced into a gas-liquid separator (320) for treatment; (III) discharging materials subjected to heat exchange in the reboiler (220) are introduced into a gas-liquid separator (320) for treatment, a secondary compressor 330 is utilized for pressurizing and heating treatment on gas phases extracted by the gas-liquid separator (320), and then the gas phases are subjected to refrigeration treatment and then flow back to the gas-liquid separator (320); In the N-level rectifying unit (200), the tower top pressure of a rectifying tower (210) of any one-level rectifying module is 0.2-0.5 MPa; The liquid phase extracted by the gas-liquid separator (320) is divided into two paths, the first path is conveyed to the low-deuterium ammonia storage unit (500), and the second path is returned to the rectifying tower (210) of the first-stage rectifying module.
  13. 13. The heat pump distillation process according to any one of claims 11 to 12, wherein in step S2, X, Y, Z1 satisfy the following relationship: , And is also provided with , Wherein X is the feeding flow rate of the raw material to be treated, kg/h, dx is the deuteration degree of the raw material to be treated; y is the feed flow rate of the heavies storage unit (400), kg/h, D Y is the deuteration of the feed to the heavies storage unit (400); z1 is the flow rate of the feed of the first path of liquid phase extracted by the gas-liquid separator (320) to the low-deuterium ammonia storage unit (500), kg/h, D Z1 is the deuteration degree of the feed of the first path; m0 is the relative molecular mass of NH 3 .
  14. 14. The heat pump rectification process of ammonia according to claim 12 or 13, wherein the liquid phase extracted by the gas-liquid separator (320) is divided into two paths, the first path has a feed rate of Z1 to the low deuterium ammonia storage unit (500), the second path has a feed rate of Z2 to the rectification column (210) of the first stage rectification module, and Z1: Z2 is 1 (20-60).
  15. 15. The heat pump rectification process of ammonia according to any one of claims 11 to 14, wherein in step S2, the pressure at the inlet of the primary compressor (310) is 0.1 to 0.5mpa, and the pressure at the outlet is 0.15 to 1.0mpa; And/or the pressure of the inlet of the secondary compressor (330) is 0.3-0.5 MPa, and the pressure of the outlet is 1.3-1.6 MPa.

Description

Heat pump rectification production equipment, system and process for ammonia Technical Field The invention belongs to the technical field of hydrogen isotope enrichment, and particularly relates to equipment, a system and a process for producing ammonia by heat pump rectification. Background With the rapid increase of deuterium demand in the fields of nuclear energy, medicine and fusion energy, domestic high deuterium water market is continuously in short supply, however, the abundance of deuterium in nature is only 0.0156%, and high-efficiency enrichment faces serious technical challenges. However, the current main stream enrichment technology has defects, the most main industrial method for producing heavy water in the world is a GS double-temperature hydrogen sulfide exchange method, the difference of hydrogen isotope exchange reaction rates between water (H 2 O/HDO) and hydrogen sulfide (H 2 S/HDS) along with the temperature change is relied on, the method relies on highly toxic and inflammable H 2 S raw materials, the problems of serious equipment corrosion, high energy cost, high environmental protection barrier approval and the like exist, and the water rectification method has the advantages of high safety, green and environment-friendly process and good device stability, but the production cost is very high due to the high enthalpy of water. The rectification of ammonia is used as one of the heavy hydrogen isotope separation methods, and the NH 3/NH2 D separation factor is 1.04 at normal pressure, so that the ammonia has the advantages of larger separation factor, stable raw materials, no corrosion and the like as a separation substance, is favorable for actual large-scale industrial production, and therefore, the selection of the liquid ammonia rectification method for hydrogen isotope enrichment is also one of the selectable modes. The Chinese patent application with publication number CN119793202A discloses a method and a system for separating hydrogen isotopes with low energy consumption, which adopt parallel industrial waste heat as a heat source, and the purpose is to combine liquid ammonia rectification with waste heat utilization, reduce energy consumption, avoid corrosion and waste water problems and realize low-cost, high-efficiency and green production. The method has the advantages of limited heat source sources, unsatisfactory separation efficiency of the rectifying tower due to mixed material flow, unstable interstage (rectifying tower), poor system stability, fluctuation of deuteration degree of products, repeated dissipation of cold energy, increased comprehensive energy consumption and the like. Thus, the use of ammonia rectification in the prior art is still subject to multiple bottlenecks of heat source, separation efficiency, interstage decoupling, energy loss, and the like. Disclosure of Invention Problems to be solved Aiming at the problems of high energy consumption and/or unsatisfactory efficiency in the existing ammonia rectification technology, the invention provides equipment, a system and a process for producing ammonia by heat pump rectification. Technical proposal In order to achieve the above purpose, the technical scheme adopted by the application is as follows: The first aspect of the invention provides a heat pump rectification device for ammonia, comprising an N-level rectification unit and a compression circulation unit; The N-level rectification unit comprises N-level rectification modules, wherein any rectification template comprises a rectification tower and a reboiler communicated with the rectification tower, and for the rectification modules of two adjacent stages, a heavy component extraction outlet of the rectification tower of the front rectification module is communicated with a raw material inlet of the rectification tower of the rear rectification module; The compression circulation unit comprises a first-stage compressor and a gas-liquid separator, wherein a light component extraction outlet of the first-stage rectification module is communicated with an inlet of the first-stage compressor of the compression circulation unit, an outlet of the first-stage compressor is communicated with an inlet of a rectification module reboiler, an outlet of the rectification module reboiler is communicated with an inlet of the gas-liquid separator, and a liquid phase outlet of the gas-liquid separator is communicated with a light component comprehensive reflux port of the first-stage rectification module. As a preferable mode of any one of the first aspect of the present invention, any one of the rectifying towers includes any one or more of the following (I) to (VII): (I) The heavy component extraction port is arranged at the lower part or the bottom of the rectifying tower; (II) the light component reflux port is arranged at the lower part or the bottom of the rectifying tower; (III) the feed inlet is disposed in the middle, upper or top of the rectifying column;