Device for producing heavy water by multi-stage heat pump decompression rectification

Abstract

The utility model belongs to the technical field of rectification separation, and particularly relates to a device for producing heavy water by multi-stage heat pump decompression rectification, which comprises a mixer, a first-stage heat pump decompression rectification tower, a second-stage heat pump decompression rectification tower, a product rectification tower and a byproduct rectification tower. According to the device, a heat pump technology and vacuum distillation are coupled together, so that the prepared heavy water is relatively high in concentration, the efficiency is high, the energy-saving effect is good, and the production cost is remarkably reduced.

Description

TECHNICAL FIELD

[0001] The utility model belongs to rectification separation technical field, concretely relates to a kind of heavy water's device of multistage heat pump pressure reduction rectification production. BACKGROUND

[0002] Heavy water is a compound composed of deuterium and oxygen, also known as deuterium oxide, with the molecular formula D2O and the relative molecular mass of 20.0275, which is about 11% higher than the relative molecular mass of ordinary water 18.0153. Since the properties of deuterium and hydrogen are very similar, the chemical properties of heavy water and ordinary water are also very similar. The special value of heavy water is reflected in the application of atomic energy technology, and its main use is as a "moderator" in nuclear reactors to reduce neutron speed and control nuclear fission process, and it is also a coolant. In addition, heavy water is also a valuable tracer material for studying chemical and physiological changes in the medical field.

[0003] The existing production methods of heavy water mainly include water rectification method, electrolysis method and catalytic exchange method. Water rectification method is a relatively simple method that uses the difference in volatility of each component in the system to separate heavy water through rectification process, and is widely used in the final enrichment of heavy water production and the upgrading process of heavy water in nuclear reactors. However, since the boiling point difference between heavy water and ordinary water is very small, a large number of theoretical tray numbers and a large amount of liquid to be treated are required, which makes the volume of the tower equipment large and the energy consumption high. Electrolysis method uses the principle that tritium ions are easily enriched on the electrode and electrolyzed into tritium gas, and it is widely used in the production of heavy water in areas with low electricity prices. This method requires high precision and complex equipment, has high energy consumption and is difficult to control. Catalytic exchange method includes water-hydrogen sulfide exchange method (GS method) and ammonia-hydrogen exchange method, which is mainly used for producing low-concentration heavy water.

[0004] Chinese patent CN20051004676.1 provides a method for bidirectional strengthening production of heavy oxygen water and heavy water. In view of the problem that the existing heavy water production process and heavy oxygen water production process have low integration level, a new production process is developed, which couples and synergistically strengthens the heavy water production process and the heavy oxygen water production process, and increases the yield of heavy water. However, there are still problems such as complex equipment and high energy consumption.

[0005] Chinese patent CN20161007733.4 provides a heavy water production method and heavy water production equipment. The equipment used in this method is an electrochemical reaction device. Water undergoes electrochemical reaction in the electrode unit, and OH free radicals are generated at the anode, and H ions and D ions are generated at the cathode. H ions are more likely to recombine with OH free radicals to form water than D ions, so that D ions self-combine to generate deuterium gas and precipitate. The gas containing deuterium gas separated from the water body is collected, and the deuterium gas reacts with oxygen to generate heavy water. However, this method has high energy consumption, and hydrogen and oxygen are generated in the system, which has the risk of explosion. The utility model discloses a kind of multi-stage heat pump vacuum rectification production heavy water devices.

[0006] In view of the deficiencies of the prior art, the utility model provides a kind of multi-stage heat pump vacuum rectification production heavy water devices.The device couples heat pump technology and vacuum rectification technology, carries out the comprehensive utilization of energy, significantly reduces energy consumption and production cost.

[0007] Specifically, the utility model provides the following technical solutions:

[0008] A kind of multi-stage heat pump vacuum rectification production heavy water device, comprising: mixer (M), first-stage heat pump vacuum rectification tower (T1), second-stage heat pump vacuum rectification tower (T2), product rectification tower (T3), byproduct rectification tower (T4);

[0009] The discharge port of the mixer (M) is connected with the feed inlet of the first-stage heat pump vacuum rectification tower (T1);

[0010] The top gas phase outlet of the first-stage heat pump vacuum rectification tower (T1) is sequentially connected with first compressor (P1), the hot fluid section of first heat exchanger (H1), the inlet of first auxiliary condenser (C1), and the outlet of the first auxiliary condenser (C1) is divided into two ways: one way is connected with the top liquid phase inlet of the first-stage heat pump vacuum rectification tower (T1), and the other way is connected with the feed inlet of the byproduct rectification tower (T4);

[0011] The bottom liquid phase outlet of the first-stage heat pump vacuum rectification tower (T1) is divided into two ways: one way is sequentially connected with the cold fluid section of first heat exchanger (H1), the bottom gas phase inlet of the first-stage heat pump vacuum rectification tower (T1), and the other way is connected with the feed inlet of the second-stage heat pump vacuum rectification tower (T2);

[0012] The top gas phase outlet of the second-stage heat pump vacuum rectification tower (T2) is sequentially connected with second compressor (P2), the hot fluid section of second heat exchanger (H2), the inlet of second auxiliary condenser (C2), and the outlet of the second auxiliary condenser (C2) is divided into two ways: one way is connected with the top liquid phase inlet of the second-stage heat pump vacuum rectification tower (T2), and the other way is connected with the feed inlet of the mixer (M);

[0013] The bottom liquid phase outlet of the second-stage heat pump vacuum rectification tower (T2) is divided into two ways: one way is sequentially connected with the cold fluid section of second heat exchanger (H2), the bottom gas phase inlet of the second-stage heat pump vacuum rectification tower (T2), and the other way is connected with the feed inlet of the product rectification tower (T3).

[0014] The heat pump in the utility model refers to the latent heat of tower top steam is recycled for heating tower kettle by adding heat pump on the basis of ordinary rectification tower, so as to achieve the purpose of energy saving and consumption reduction.

[0015] As preferred, the overhead vapor outlet of the product rectification column (T3) is connected in sequence with the third compressor (P3), the hot fluid section of the third heat exchanger (H3), the inlet of the third auxiliary condenser (C3), the outlet of the third auxiliary condenser (C3) is divided into two routes: one is connected with the overhead liquid inlet of the product rectification column (T3), and the other is connected with the feed inlet of the mixer (M);

[0016] The bottom liquid outlet of the product rectification column (T3) is divided into two routes: one is connected in sequence with the cold fluid section of the third heat exchanger (H3) and the bottom vapor inlet of the product rectification column (T3), and the other is used to lead out heavy water product;

[0017] The overhead vapor outlet of the by-product rectification column (T4) is connected in sequence with the fourth compressor (P4), the hot fluid section of the fourth heat exchanger (H4), the inlet of the fourth auxiliary condenser (C4), the outlet of the fourth auxiliary condenser (C4) is divided into two routes: one is connected with the overhead liquid inlet of the by-product rectification column (T4), and the other is used to lead out a product containing heavy water;

[0018] The bottom liquid outlet of the by-product rectification column is divided into two routes: one is connected in sequence with the cold fluid section of the fourth heat exchanger (H4) and the bottom vapor inlet of the by-product rectification column (T4), and the other is connected with the feed inlet of the mixer (M).

[0019] In the utility model, the by-product rectification column (T4) is used for extracting light water (H2O) in the top stream of the first heat pump pressure reduction rectification column (T1) as a by-product and sending the low-concentration heavy water obtained from the bottom of the T4 column back to the T1 for continuous separation.

[0020] As preferred, the number of theoretical plates of the first heat pump pressure reduction rectification column (T1) is 84-95, and the feed position is the 44th-48th theoretical plate.

[0021] As preferred, the number of theoretical plates of the second heat pump pressure reduction rectification column (T2) is 84-95, and the feed position is the 35th-38th theoretical plate.

[0022] As preferred, the number of theoretical plates of the product rectification column (T3) is 84-95, and the feed position is the 30th-35th theoretical plate.

[0023] As preferred, the number of theoretical plates of the by-product rectification column (T4) is 84-95, and the feed position is the 57th-62nd theoretical plate.

[0024] Research finds that too few theoretical plates or improper feed position will result in low concentration of heavy water product.

[0025] The method for producing heavy water by the device has the following steps:

[0026] (1) The low-concentration heavy water raw material from the outside world is mixed with the stream from the top of the secondary heat pump vacuum rectification tower (T2), the stream from the bottom of the product rectification tower (T3) and the stream from the top of the byproduct rectification tower (T4) through the mixer (M) and then enters the primary heat pump vacuum rectification tower (T1), the ascending gas in the tower and the descending liquid continuously perform mass and heat transfer, the stream from the top of the tower is pressurized and heated by the first compressor (P1), exchanges heat with the stream from the bottom of the tower in the first heat exchanger (H1), is completely condensed into a liquid phase by the first auxiliary condenser (C1), part of which returns to the top of the primary heat pump vacuum rectification tower (T1), and part of which flows into the product rectification tower (T4) as the top product stream; part of the stream from the bottom of the tower is heated into steam in the first heat exchanger (H1) and returns to the primary heat pump vacuum rectification tower (T1), and part of which flows into the secondary heat pump vacuum rectification tower (T2) as the bottom product stream;

[0027] (2) The stream from the bottom of the primary reaction rectification tower (T1) enters the secondary heat pump vacuum rectification tower (T2) as the raw material, the top and bottom streams thereof undergo the same process as the primary heat pump vacuum rectification tower (T1) and then the heavy water with a higher concentration from the bottom flows into the product rectification tower (T3) to further remove light components, and the heavy water with a low concentration from the top enters the mixer (M) through a pipeline and returns to the primary heat pump vacuum rectification tower (T1) for circulation rectification;

[0028] (3) The heavy water with a higher concentration from the bottom of the secondary heat pump vacuum rectification tower (T2) enters the product rectification tower (T3) as the raw material for further rectification, the top and bottom streams thereof undergo the same process as the primary heat pump vacuum rectification tower (T1) and then the heavy water product with a high concentration is obtained from the bottom, and the heavy water with a low concentration from the top enters the mixer (M) through a pipeline and returns to the primary heat pump vacuum rectification tower (T1) for circulation rectification;

[0029] (4) The mixture from the top of the primary heat pump vacuum rectification tower (T1) enters the byproduct rectification tower (T4) as the raw material, the top and bottom streams thereof undergo the same process as the primary heat pump vacuum rectification tower (T1) and then the product containing a small amount of heavy water is obtained from the top, and the heavy water with a low concentration from the bottom is conveyed into the mixer (M) through a pipeline and returns to the primary heat pump vacuum rectification tower (T1) for circulation rectification.

[0030] The device provided by the utility model takes the low-concentration heavy water as the raw material, the quality concentration of the heavy water product produced by the multi-stage heat pump vacuum rectification is above 99.78%, compared with the process of producing heavy water by conventional vacuum rectification, the production cost can be reduced by more than 24.00%, the energy consumption can be saved by more than 68.00%, and the device has good economy.

[0031] The utility model discloses at least in the following:

[0032] 1) the utility model provides a multistage heat pump pressure reduction rectification production heavy water's device, and conventional pressure reduction rectification production heavy water's device compares, has saved four condensers and four reboilers, has carried out the comprehensive utilization of energy, not only obtained the energy -conserving effect, also reduced the production cost remarkably;

[0033] 2) the utility model provides a multistage heat pump pressure reduction rectification production heavy water's device, simple structure is required, the reaction condition is mild, and the operability is strong, has good economic, social benefit;

[0034] 3) the utility model provides a multistage heat pump pressure reduction rectification production heavy water's device, with low concentration heavy water as raw material, and the quality concentration of the product heavy water obtained in production is 99.78wt% or more, and compared with conventional pressure reduction rectification, the production cost can be reduced by 24.00% or more, and the energy consumption can be saved by 68.00% or more;

[0035] 4) the utility model provides a multistage heat pump pressure reduction rectification production heavy water's device, further improves heavy water product concentration by optimizing theoretical plate number and feed position. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 The utility model provides a multistage heat pump pressure reduction rectification production heavy water's device's structure schematic view.

[0037] Figure 1 In the middle, T1-first heat pump pressure reduction rectification tower, T2-second heat pump pressure reduction rectification tower, T3-product rectification tower, T4-byproduct rectification tower, P1-first compressor, P2-second compressor, P3-third compressor, P4-fourth compressor, H1-first heat exchanger, H2-second heat exchanger, H3-third heat exchanger, H4-fourth heat exchanger, V1-first pressure reducing valve, V2-second pressure reducing valve, V3-third pressure reducing valve, V4-fourth pressure reducing valve, C1-first auxiliary condenser, C2-second auxiliary condenser, C3-third auxiliary condenser, C4-fourth auxiliary condenser, M-mixer. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical scheme and advantage of the utility model more clear, the technical scheme in the utility model embodiment is described clearly and completely below, and the following embodiments are used to explain the utility model, but not to limit the scope of the utility model. The technical or condition not noted in the embodiment is according to the technology or condition described in the literature in the field, or according to the product manual.

[0039] The following embodiments take 100kg / h of processing capacity as an example.

[0040] Embodiment 1

[0041] Embodiment 1 provides a device for producing heavy water by multi-stage heat pump vacuum rectification, as shown in the figure, comprising: a mixer (M), a first-stage heat pump vacuum rectification tower (T1), a second-stage heat pump vacuum rectification tower (T2), a product rectification tower (T3), and a by-product rectification tower (T4); Figure 1 The outlet of the mixer (M) is connected to the inlet of the first-stage heat pump vacuum rectification tower (T1);

[0042] The top gas phase outlet of the first-stage heat pump vacuum rectification tower (T1) is sequentially connected to a first compressor (P1), a hot fluid section of a first heat exchanger (H1), a first pressure reduction valve (V1), and an inlet of a first auxiliary condenser (C1). The outlet of the first auxiliary condenser (C1) is divided into two paths: one path is connected to the top liquid phase inlet of the first-stage heat pump vacuum rectification tower (T1), and the other path is connected to the inlet of the by-product rectification tower (T4);

[0043] The bottom liquid phase outlet of the first-stage heat pump vacuum rectification tower (T1) is divided into two paths: one path is sequentially connected to a cold fluid section of the first heat exchanger (H1) and the bottom gas phase inlet of the first-stage heat pump vacuum rectification tower (T1), and the other path is connected to the inlet of the second-stage heat pump vacuum rectification tower (T2);

[0044] The top gas phase outlet of the second-stage heat pump vacuum rectification tower (T2) is sequentially connected to a second compressor (P2), a hot fluid section of a second heat exchanger (H2), a second pressure reduction valve (V2), and an inlet of a second auxiliary condenser (C2). The outlet of the second auxiliary condenser (C2) is divided into two paths: one path is connected to the top liquid phase inlet of the second-stage heat pump vacuum rectification tower (T2), and the other path is connected to the inlet of the mixer (M);

[0045] The bottom liquid phase outlet of the second-stage heat pump vacuum rectification tower (T2) is divided into two paths: one path is sequentially connected to a cold fluid section of the second heat exchanger (H2) and the bottom gas phase inlet of the second-stage heat pump vacuum rectification tower (T2), and the other path is connected to the inlet of the product rectification tower (T3);

[0046] The top gas phase outlet of the product rectification tower (T3) is sequentially connected to a third compressor (P3), a hot fluid section of a third heat exchanger (H3), a third pressure reduction valve (V3), and an inlet of a third auxiliary condenser (C3). The outlet of the third auxiliary condenser (C3) is divided into two paths: one path is connected to the top liquid phase inlet of the product rectification tower (T3), and the other path is connected to the inlet of the mixer (M);

[0047] The top gas phase outlet of the product rectification tower (T3) is sequentially connected to a third compressor (P3), a hot fluid section of a third heat exchanger (H3), a third pressure reduction valve (V3), and an inlet of a third auxiliary condenser (C3). The outlet of the third auxiliary condenser (C3) is divided into two paths: one path is connected to the top liquid phase inlet of the product rectification tower (T3), and the other path is connected to the inlet of the mixer (M);

[0048] The bottom liquid phase outlet of the product rectification tower (T3) is divided into two paths: one path is connected with the cold fluid section of the third heat exchanger (H3) and the bottom gas phase inlet of the product rectification tower (T3) in sequence, and the other path leads to the heavy water product;

[0049] The top gas phase outlet of the by-product rectification tower (T4) is connected with the fourth compressor (P4), the hot fluid section of the fourth heat exchanger (H4), the fourth pressure reducing valve (V4) and the inlet of the fourth auxiliary condenser (C4) in sequence, and the outlet of the fourth auxiliary condenser (C4) is divided into two paths: one path is connected with the top liquid phase inlet of the by-product rectification tower (T4), and the other path leads to the product containing heavy water;

[0050] The bottom liquid phase outlet of the by-product rectification tower is divided into two paths: one path is connected with the cold fluid section of the fourth heat exchanger (H4) and the bottom gas phase inlet of the by-product rectification tower (T4) in sequence, and the other path is connected with the feed inlet of the mixer (M).

[0051] Example 2

[0052] Example 2 uses the device provided in Example 1 to produce heavy water, and the condition parameters are as follows:

[0053] The fresh raw material feed temperature is 25℃, the low-concentration heavy water flow is 330kg / h, the theoretical plate number of the first-stage heat pump rectification tower (T1) is 88, the feed plate is 46, the operating pressure is 10kPa, the compression ratio of the compressor (P1) is 2.5, the theoretical plate number of the second-stage heat pump rectification tower (T2) is 88, the feed plate is 37, the operating pressure is 10kPa, the compression ratio of the compressor (P2) is 2.5, the theoretical plate number of the product rectification tower (T3) is 88, the feed plate is 34, the operating pressure is 10kPa, the compression ratio of the compressor (P3) is 2.3, the theoretical plate number of the by-product rectification tower (T4) is 88, the feed plate is 59, the operating pressure is 10kPa, the compression ratio of the compressor (P4) is 3, and the mass purity of the obtained product heavy water is 99.78wt%, which saves 24.74% compared with the conventional rectification TAC and saves 71.93% in energy consumption.

[0054] In order to illustrate the technical advantages of the present application in energy saving and reducing production cost, the data comparison between the multi-stage heat pump vacuum rectification process and the conventional vacuum rectification process (the latent heat of the tower top steam is not recovered for heating the tower kettle) is carried out, and the results are as shown in the following table 1.

[0055] Table 1 Comparison data of multi-stage heat pump vacuum rectification and conventional vacuum rectification process

[0056]

[0057] As shown in Table 1, the device for producing heavy water by multi-stage heat pump pressure reduction rectification has very obvious technical advantages in energy saving and reducing production cost.

[0058] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A device for producing heavy water by multi-stage heat pump pressure reducing rectification, characterized in that, The system comprises a mixer, a first heat pump vacuum rectifying column, a second heat pump vacuum rectifying column, a product rectifying column, and a byproduct rectifying column. The top outlet of the first heat pump vacuum rectifying column is connected with a first compressor, a hot fluid section of a first heat exchanger, and an inlet of a first auxiliary condenser in sequence. The outlet of the first auxiliary condenser is divided into two paths, one of which is connected with the top inlet of the first heat pump vacuum rectifying column, and the other of which is connected with the feed inlet of the byproduct rectifying column.

2. The apparatus for the production of heavy water by multi-stage heat pump pressure reducing rectification according to claim 1, characterized in that, The bottom outlet of the first heat pump vacuum rectifying column is divided into two paths, one of which is connected with a cold fluid section of the first heat exchanger and the bottom inlet of the first heat pump vacuum rectifying column in sequence, and the other of which is connected with the feed inlet of the second heat pump vacuum rectifying column. The top gas phase outlet of the product rectifying column is connected with a third compressor, a hot fluid section of a third heat exchanger, and an inlet of a third auxiliary condenser in sequence. The outlet of the third auxiliary condenser is divided into two paths, one of which is connected with the top inlet of the product rectifying column, and the other of which is connected with the feed inlet of the mixer. The bottom outlet of the product rectifying column is divided into two paths, one of which is connected with a cold fluid section of the third heat exchanger and the bottom inlet of the product rectifying column in sequence, and the other of which leads to a heavy water product.

3. The apparatus for producing heavy water by multi-stage heat pump pressure reducing rectification according to claim 1 or 2, characterized in that, The top outlet of the byproduct rectifying column is connected with a fourth compressor, a hot fluid section of a fourth heat exchanger, and an inlet of a fourth auxiliary condenser in sequence.

4. The apparatus for producing heavy water by multi-stage heat pump pressure reducing rectification according to claim 1 or 2, characterized in that, The outlet of the fourth auxiliary condenser is divided into two paths, one of which is connected with the top inlet of the byproduct rectifying column, and the other of which leads to a product containing heavy water.

5. The device for producing heavy water by multi-stage heat pump vacuum distillation according to claim 1 or 2, characterized in that: The bottom outlet of the byproduct rectifying column is divided into two paths, one of which is connected with a cold fluid section of the fourth heat exchanger and the bottom inlet of the byproduct rectifying column in sequence, and the other of which is connected with the feed inlet of the mixer.

6. The apparatus for producing heavy water by multi-stage heat pump pressure reducing rectification according to claim 1 or 2, characterized in that, The first heat pump vacuum rectifying column has 84-95 theoretical plates, and the feed position is at the 44th-48th theoretical plate. The second heat pump vacuum rectifying column has 84-95 theoretical plates, and the feed position is at the 35th-38th theoretical plate. The product rectifying column has 84-95 theoretical plates, and the feed position is at the 30th-35th theoretical plate. The byproduct rectifying column has 84-95 theoretical plates, and the feed position is at the 57th-62nd theoretical plate.

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