A device and method for collecting and pressurizing lean materials in a 1,000-ton uranium enrichment cascade

Abstract

The present invention relates to the field of uranium enrichment cascade supply and withdrawal, and in particular to a 1,000-ton uranium enrichment cascade lean material receiving and pressurizing device and method. The device comprises: a first medium passage and a second medium passage are arranged between the inlet main pipeline and the outlet main pipeline, and the first medium passage and the second medium passage are connected in parallel; each medium passage comprises at least two magnetic levitation compressors connected in series; during operation, the frequency ratio of the front-stage magnetic levitation compressor to the rear-stage magnetic levitation compressor is 31~33:27~29; under abnormal working conditions, after frequency increase, the frequency ratio of the front-stage magnetic levitation compressor to the rear-stage magnetic levitation compressor is 35~37:29~31. Pressurization is performed using the device. The present invention meets the requirements of the 1,000-ton uranium enrichment cascade lean material receiving system for flow rate and pressure increase, and has high continuous operation stability.

Description

Technical Field

[0001] The present invention relates to the field of uranium enrichment cascade feed and withdrawal, and in particular to a pressurizing device and method for collecting depleted uranium in a thousand-ton uranium enrichment cascade. Background Art

[0002] The existing depleted uranium collection system for uranium enrichment cascade adopts a pressurized cooling method. The pressurization process of the working medium before entering the cooling container is the core of the entire process.

[0003] In the depleted uranium collection system of uranium enrichment cascade, in order to enable the working medium to sublimate from gas to solid and continuously store it inside the depleted uranium collection container, a pressurized cooling method is adopted. In order to ensure the continuous and stable operation of the cascade and the continuity of the pressurized cooling collection process, the inlet pressure and outlet pressure of the pressurization system are usually controlled, and the temperature of the conveying pipeline is maintained to ensure that the pressurized working medium can still flow in the pipeline in a gaseous state.

[0004] For the pressurization of depleted uranium collection in a thousand-ton uranium enrichment cascade, the main process difficulty lies in the pressurization of a large flow of medium and the continuous and stable operation of the entire system. On the one hand, due to the doubling of the production capacity of the production line, the flow rate of this system doubles, and a suitable pressurization method needs to be selected to ensure the efficiency of collection; on the other hand, since this system has a decisive impact on the continuous and stable operation of the cascade system, once this system fails, the entire cascade system will face the risk of complete shutdown, and a suitable pressurization method needs to be selected to ensure the continuity of collection.

[0005] In the existing pressurized cooling process, a booster compressor is usually used as the front stage and a Roots pump is used as the rear stage. Through two-stage pressure boosting, the pressure of the working medium is increased by one order of magnitude, that is, the ratio of the outlet pressure to the inlet pressure is 15-20:1 to meet the collection requirements.

[0006] A Roots pump is a mechanical vacuum pump with a pair of synchronously rotating sole-shaped rotors. It cannot pump air alone and has no internal compression. Therefore, the compression ratio is usually very low, so a front-stage pump is required. The front-stage pump needs to be equipped with oil seals, water rings, etc. that can be directly discharged to the atmosphere. The ultimate vacuum of the Roots pump depends not only on the structure and manufacturing precision of the pump itself but also on the ultimate vacuum of the front-stage pump.

[0007] When using a booster compressor and a Roots pump in series for pressurization, the booster compressor needs to be refueled and maintained regularly to ensure the lubrication effect and the sealing performance of the booster compressor. The lubricating oil added will contact the working medium, thereby affecting the purity of the working medium. The Roots pump is a positive displacement pump, and its working compression components require high-precision matching. However, powder will be generated in the uranium enrichment cascade, which will periodically cause the Roots pump to jam and affect the continuous operation of the cascade system; moreover, its power consumption is high and the operating noise is large. Further, the Roots pump used in the uranium enrichment industry is an imported pump. Summary of the invention

[0008] The technical problem to be solved by the present invention is to provide a 1,000-ton uranium enrichment cascade lean material receiving and pressurizing device and method, which meet the requirements of the 1,000-ton uranium enrichment cascade lean material receiving system for flow rate and pressure increase and have high continuous operation stability.

[0009] The present invention provides a 1,000-ton uranium enrichment cascade lean material collecting and pressurizing device, comprising: a first medium passage and a second medium passage are arranged between an inlet main pipeline and an outlet main pipeline, the first medium passage and the second medium passage are connected in parallel;

[0010] Each medium passage includes at least two magnetic suspension compressors connected in series; the inlet pressure of the inlet main pipeline is not higher than 1.33 kPa, and the outlet pressure of the outlet main pipeline is not higher than 20 kPa;

[0011] Based on the power consumption balance principle and gas dynamic characteristics of the magnetic levitation compressor, it is verified through experiments that under normal operating conditions, the frequency ratio of the front-stage magnetic levitation compressor and the rear-stage magnetic levitation compressor must meet 31~33:27~29 to ensure the lowest overall power and that the flow and pressure increase meet the requirements of the kiloton system.

[0012] Under abnormal working conditions, the magnetic levitation compressors need to be upgraded at the same time, and the frequency increase value of the front-stage magnetic levitation compressor is higher than that of the rear-stage magnetic levitation compressor. After upgrading, the frequency ratio of the front-stage magnetic levitation compressor and the rear-stage magnetic levitation compressor is adjusted to 35~37:29~31 to compensate for the pressure loss during single-channel operation and avoid a surge in power consumption due to excessive frequency increase.

[0013] In a specific embodiment of the present invention, it further comprises: a third medium passage;

[0014] The third medium passage is connected in parallel with the first medium passage;

[0015] The third medium passage includes at least two magnetic suspension compressors connected in series.

[0016] In a specific embodiment of the present invention, it further comprises: a fourth medium passage;

[0017] The fourth medium passage is connected in parallel with the first medium passage;

[0018] The fourth medium passage includes at least two magnetic suspension compressors connected in series.

[0019] In a specific embodiment of the present invention, the medium flow rate of the inlet main pipeline is 60-75 g / s.

[0020] In a specific embodiment of the present invention, all pipes are wrapped with electric heating tapes on the outside, and the heating temperature is 55-65°C.

[0021] In a specific embodiment of the present invention, the maximum compression ratio of the magnetic levitation compressor is 10.

[0022] In a specific embodiment of the present invention, during operation, the frequency ratio of the front-stage magnetic levitation compressor to the rear-stage magnetic levitation compressor is 8:7;

[0023] Under abnormal working conditions, after frequency increase, the frequency ratio of the front-stage magnetic levitation compressor to the rear-stage magnetic levitation compressor is 6:5.

[0024] The present invention provides a method for collecting and pressurizing lean materials in a 1,000-ton uranium enrichment cascade, comprising the following steps:

[0025] Step S1: setting a first medium passage, a second medium passage, a third medium passage and a fourth medium passage in parallel between the inlet main pipeline and the outlet main pipeline;

[0026] Each medium path includes at least two magnetic suspension compressors connected in series;

[0027] Step S2: collecting and pressurizing the lean material of the uranium enrichment cascade, the first medium passage and the second medium passage work synchronously, the third medium passage is in standby mode, and the fourth medium passage is used for maintenance;

[0028] The inlet pressure of the inlet main pipeline is controlled to be no higher than 1.33 kPa, and the outlet pressure of the outlet main pipeline is controlled to be no higher than 20 kPa;

[0029] During operation, under the condition of maintaining the lowest overall power, the frequency of the front-stage magnetic suspension compressor is higher than the frequency of the rear-stage magnetic suspension compressor; the frequency ratio of the front-stage magnetic suspension compressor to the rear-stage magnetic suspension compressor is 31~33:27~29;

[0030] Under abnormal working conditions, the magnetic levitation compressors are frequency-upgraded at the same time, and the frequency increase value of the front-stage magnetic levitation compressor is higher than that of the rear-stage magnetic levitation compressor; after frequency upgradation, the frequency ratio of the front-stage magnetic levitation compressor to the rear-stage magnetic levitation compressor is 35~37:29~31.

[0031] In a specific embodiment of the present invention, during the operation, the frequency ratio of the front-stage magnetic levitation compressor to the rear-stage magnetic levitation compressor is 8:7;

[0032] Under abnormal working conditions, after frequency increase, the frequency ratio of the front-stage magnetic levitation compressor to the rear-stage magnetic levitation compressor is 6:5.

[0033] In a specific embodiment of the present invention, the medium flow rate of the inlet main pipeline is 60-75 g / s.

[0034] Compared with the prior art, the device and method for collecting and pressurizing kiloton uranium enrichment cascade lean materials of the present invention have the following beneficial effects:

[0035] (1) The use of multiple magnetic suspension compressors to cooperate completely replaces the pressurization method of Roots pumps and booster machines. The equipment is oil-free and maintenance-free, achieving the technical effect of no pollution to the working medium and no maintenance required during operation;

[0036] (2) The entire pressurizing device is equipped with multiple medium passages, and each medium passage is combined with the frequency coordination of multiple magnetic levitation compressors. By optimizing the frequency ratio (8:7 and 6:5), the kiloton system can achieve precise control of flow (60~75g / s) and pressure (inlet ≤1.33kPa, outlet ≤20kPa), reducing the overall power consumption by more than 30% and achieving high continuous operation stability;

[0037] (3) It is not sensitive to the influence of powder, achieving the technical effect of long-term safe, stable and continuous operation;

[0038] (4) The use of magnetic levitation compressor technology achieves the technical effects of low power consumption and low noise;

[0039] (5) The use of magnetic levitation compressor technology has achieved autonomous and controllable technical effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 A schematic diagram showing the structure of a 1,000-ton uranium enrichment cascade lean material receiving and pressurizing device;

[0041] In the figure, 1 is the front-stage magnetic levitation compressor, 2 is the rear-stage magnetic levitation compressor, 3 is the inlet main pipeline, and 4 is the outlet main pipeline. DETAILED DESCRIPTION

[0042] In order to further understand the present invention, the embodiments of the present invention are described below in conjunction with examples, but it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the present invention.

[0043] In the present invention, a magnetic suspension compressor is used as a pressurizing unit, and through a specific series-parallel design, the requirements for flow rate and pressure increase of a thousand-ton uranium enrichment cascade lean material receiving system are met.

[0044] The embodiment of the present invention discloses a 1,000-ton uranium enrichment cascade lean material receiving and pressurizing device, such as Figure 1 As shown, a first medium passage and a second medium passage are provided between the inlet main pipeline 3 and the outlet main pipeline 4, and the first medium passage and the second medium passage are connected in parallel;

[0045] Each medium path includes at least two magnetic suspension compressors connected in series;

[0046] Taking into account the compression requirements, reliability and cost, it is preferred to connect two magnetic levitation compressors in series.

[0047] The maximum compression ratio of each magnetic levitation compressor is 10.

[0048] The front-stage magnetic suspension compressor 1 is close to the inlet main pipeline 3, and the rear-stage magnetic suspension compressor 2 is close to the outlet main pipeline 4;

[0049] In order to make the whole device run stably and avoid unnecessary shutdown, it is preferred to further include: a third medium passage and a fourth medium passage;

[0050] The third medium passage, the fourth medium passage, and the second medium passage are all connected in parallel with the first medium passage.

[0051] The third medium passage is for backup, and the fourth medium passage is for maintenance;

[0052] The structures of the third medium passage and the fourth medium passage are consistent with those of the first medium passage, and include at least two magnetic suspension compressors.

[0053] The inlet pressure of the inlet main pipeline 3 is not higher than 1.33 kPa, and the outlet pressure of the outlet main pipeline 4 is not higher than 20 kPa, so as to avoid the subsequent connection hose from rupturing due to excessive outlet pressure;

[0054] The medium flow rate of the inlet main pipeline is 60~75g / s.

[0055] During the operation of the series-connected magnetic levitation compressors, the coupling of the operating frequencies is the key to ensuring the operation of the process.

[0056] Operating frequency coupling needs to obey the following principles:

[0057] 1) The power consumption balance principle: during operation, the power of the two magnetic levitation compressors in series must be basically the same, so as to ensure the lowest overall power;

[0058] 2) The frequency is high at the beginning and low at the end. During operation, the frequency of the front-stage magnetic levitation compressor 1 should be higher than the frequency of the rear-stage magnetic levitation compressor 2;

[0059] In the centrifugal cascade lean material collection system, there are two main purposes for designing a pressurizing device. One is to extract the lean material generated by the cascade from the cascade in time to prevent the entire cascade from being closed due to excessive pressure at the end of the cascade; the other is to collect the working material from gas to solid by pressurized cooling at the end of the cascade. There are many factors that affect the operating state of the pressurizing device, including the physical and chemical properties of the working medium, the working environment temperature, the length of the pipeline, the radius of the pipeline, the state of the collection container, etc. In the actual frequency determination process, it is difficult to use the established formula to derive and determine the frequency of the front-stage magnetic levitation compressor 1 and the rear-stage magnetic levitation compressor 2, and it is usually carried out by experimental methods.

[0060] The test method is divided into the following steps:

[0061] (1) When the magnetic levitation compressor is put into use for the first time, the two-stage magnetic levitation compressor is first started to a lower frequency (such as 20 Hz) under vacuum;

[0062] (2) Then, a portion of the working substance is slowly charged into the passage;

[0063] (3) As the medium is filled, observe the pressure ratio between the outlet and the inlet of the passage to ensure that the inlet pressure is ≤1.33 kPa and the outlet pressure is ≤20 kPa;

[0064] (4) If the conditions cannot be met, the frequency of the two-stage magnetic levitation compressor is appropriately increased to meet the control conditions;

[0065] (5) When the flow rate of the circuit reaches the maximum flow rate, the power of the front-stage magnetic levitation compressor 1 and the rear-stage magnetic levitation compressor 2 is observed. By adjusting the frequencies of the two-stage magnetic levitation compressors respectively, the power of the front-stage magnetic levitation compressor 1 and the rear-stage magnetic levitation compressor 2 is made consistent while ensuring that the pressure ratio between the outlet and the inlet remains unchanged and the inlet pressure is ≤1.33 kPa and the outlet pressure is ≤20 kPa.

[0066] Through the above test steps, under normal working conditions, when the frequency ratio is 31~33:27~29, the total power of the series magnetic levitation compressor is the lowest and meets the requirement of outlet pressure ≤20kPa.

[0067] For abnormal working conditions, the test process is similar to that under normal working conditions, except that:

[0068] (1) It is necessary to manually adjust the flow of dual channels to a single channel;

[0069] (2) Simultaneously increase the frequency of the two-stage magnetic levitation compressor to ensure that the control conditions of inlet pressure ≤ 1.33 kPa and outlet pressure ≤ 20 kPa are met;

[0070] (3) When all lean materials pass through a single path, the power of the front-stage magnetic levitation compressor 1 and the rear-stage magnetic levitation compressor 2 is observed. By adjusting the frequencies of the two-stage magnetic levitation compressors respectively, the power of the front-stage magnetic levitation compressor 1 and the rear-stage magnetic levitation compressor 2 is made consistent while ensuring that the pressure ratio between the outlet and the inlet remains unchanged and that the inlet pressure is ≤1.33 kPa and the outlet pressure is ≤20 kPa.

[0071] Under abnormal working conditions, when operating in a single channel, the frequency ratio of the front-stage magnetic levitation compressor 1 and the rear-stage magnetic levitation compressor 2 needs to be increased to 35~37:29~31 to compensate for the pressure loss and maintain system stability.

[0072] Therefore, during operation, that is, the first medium passage and the second medium passage are both operating normally, in any medium passage, under the condition of maintaining the lowest overall power, the frequency of the front-stage magnetic levitation compressor 1 is higher than the frequency of the rear-stage magnetic levitation compressor 2; the frequency ratio of the front-stage magnetic levitation compressor 1 to the rear-stage magnetic levitation compressor 2 is 31~33:27~29, preferably 8:7;

[0073] Under abnormal working conditions, that is, only one of the first medium passage and the second medium passage is in operation, the magnetic levitation compressors are up-converted at the same time, and the frequency increase value of the front-stage magnetic levitation compressor 1 is higher than that of the rear-stage magnetic levitation compressor 2; after the frequency increase, the frequency ratio of the front-stage magnetic levitation compressor 1 to the rear-stage magnetic levitation compressor 2 is 35~37:29~31, preferably 6:5.

[0074] In the 1,000-ton uranium enrichment cascade lean material receiving and pressurizing device of the present invention, electric heating belts are wound around the outside of all pipelines, and the heating temperature is 55-65° C. to prevent gas condensation in the pipelines.

[0075] The embodiment of the present invention also discloses a method for collecting and pressurizing lean materials in a 1,000-ton uranium enrichment cascade, comprising the following steps:

[0076] Step S1: setting a first medium passage, a second medium passage, a third medium passage and a fourth medium passage in parallel between the inlet main pipeline 3 and the outlet main pipeline 4;

[0077] Each medium path includes at least two magnetic suspension compressors connected in series;

[0078] Step S2: collecting and pressurizing the lean material of the uranium enrichment cascade, the first medium passage and the second medium passage work synchronously, the third medium passage is in standby mode, and the fourth medium passage is used for maintenance;

[0079] The inlet pressure of the inlet main pipeline 3 is controlled to be no higher than 1.33 kPa, and the outlet pressure of the outlet main pipeline 4 is controlled to be no higher than 20 kPa;

[0080] The medium flow rate of the inlet main pipeline 3 is 60~75g / s;

[0081] During operation, under the condition of maintaining the lowest overall power, the operating frequency of the front-stage magnetic levitation compressor 1 is higher than that of the rear-stage magnetic levitation compressor 2; the frequency ratio of the front-stage magnetic levitation compressor 1 to the rear-stage magnetic levitation compressor 2 is 31-33:27-29, preferably 8:7;

[0082] Under abnormal working conditions, the magnetic levitation compressors are frequency-upgraded at the same time, and the frequency increase value of the front-stage magnetic levitation compressor 1 is higher than that of the rear-stage magnetic levitation compressor 2; after frequency upgradation, the frequency ratio of the front-stage magnetic levitation compressor 1 to the rear-stage magnetic levitation compressor 2 is 35~37:29~31, preferably 6:5.

[0083] The kiloton-class uranium enrichment cascade lean material collecting and pressurizing device of the present invention is used for pressurized collecting. The maximum compression ratio (10:1) of the magnetic levitation compressor matches the inlet / outlet pressure range (1.33-20 kPa), ensuring efficient pressurization at a kiloton-class flow rate (60-75 g / s). The system can run continuously for 1000 hours with stable operation, and the flow rate and pressure increase meet the requirements.

[0084] The above embodiments are only used to help understand the method and core idea of ​​the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0085] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A 1,000-ton uranium enrichment cascade lean material receiving and pressurizing device, characterized in that: include: A first medium passage and a second medium passage are arranged between the inlet main pipeline and the outlet main pipeline, and the first medium passage and the second medium passage are connected in parallel; Each medium passage includes at least two magnetic suspension compressors connected in series; the inlet pressure of the inlet main pipeline is not higher than 1.33 kPa, and the outlet pressure of the outlet main pipeline is not higher than 20 kPa; During operation, under the condition of maintaining the lowest overall power, the frequency of the front-stage magnetic suspension compressor is higher than the frequency of the rear-stage magnetic suspension compressor; the frequency ratio of the front-stage magnetic suspension compressor to the rear-stage magnetic suspension compressor is 31-33:27-29; Under abnormal working conditions, the magnetic levitation compressors are frequency-upgraded at the same time, and the frequency increase value of the front-stage magnetic levitation compressor is higher than that of the rear-stage magnetic levitation compressor; after frequency-upgrading, the frequency ratio of the front-stage magnetic levitation compressor to the rear-stage magnetic levitation compressor is 35-37:29-31; All pipes are wrapped with electric heating tapes on the outside, with a heating temperature of 55 to 65°C.

2. The 1,000-ton uranium enrichment cascade lean material receiving and pressurizing device according to claim 1, characterized in that: Also included: a third medium passage; The third medium passage is connected in parallel with the first medium passage; The third medium passage includes at least two magnetic suspension compressors connected in series.

3. The 1,000-ton uranium enrichment cascade lean material receiving and pressurizing device according to claim 2, characterized in that: Also includes: a fourth medium passage; The fourth medium passage is connected in parallel with the first medium passage; The fourth medium passage includes at least two magnetic suspension compressors connected in series.

4. The 1,000-ton uranium enrichment cascade lean material receiving and pressurizing device according to claim 1, characterized in that: The medium flow rate of the inlet main pipeline is 60-75 g / s.

5. The 1,000-ton uranium enrichment cascade lean material receiving and pressurizing device according to claim 1, characterized in that: The maximum compression ratio of the magnetic suspension compressor is 10.

6. The 1,000-ton uranium enrichment cascade lean material receiving and pressurizing device according to claim 1, characterized in that: During operation, the frequency ratio of the front-stage magnetic levitation compressor to the rear-stage magnetic levitation compressor is 8:7; Under abnormal working conditions, after frequency increase, the frequency ratio of the front-stage magnetic levitation compressor to the rear-stage magnetic levitation compressor is 6:

5.

7. A method for collecting and pressurizing lean materials in a 1,000-ton uranium enrichment cascade, characterized in that: The following steps are involved: Step S1: setting a first medium passage, a second medium passage, a third medium passage and a fourth medium passage in parallel between the inlet main pipeline and the outlet main pipeline; Each medium path includes at least two magnetic suspension compressors connected in series; Step S2: collecting and pressurizing the lean material of the uranium enrichment cascade, the first medium passage and the second medium passage work synchronously, the third medium passage is in standby mode, and the fourth medium passage is used for maintenance; The inlet pressure of the inlet main pipeline is controlled to be no higher than 1.33 kPa, and the outlet pressure of the outlet main pipeline is controlled to be no higher than 20 kPa; During operation, under the condition of maintaining the lowest overall power, the frequency of the front-stage magnetic suspension compressor is higher than the frequency of the rear-stage magnetic suspension compressor; the frequency ratio of the front-stage magnetic suspension compressor to the rear-stage magnetic suspension compressor is 31-33:27-29; Under abnormal working conditions, the magnetic levitation compressors are frequency-upgraded at the same time, and the frequency increase value of the front-stage magnetic levitation compressor is higher than that of the rear-stage magnetic levitation compressor; after frequency upgradation, the frequency ratio of the front-stage magnetic levitation compressor to the rear-stage magnetic levitation compressor is 35~37:29~31.

8. The method for collecting and pressurizing kiloton uranium enrichment cascade lean materials according to claim 7, characterized in that: During the operation, the frequency ratio of the front-stage magnetic suspension compressor to the rear-stage magnetic suspension compressor is 8:7; Under abnormal working conditions, after frequency increase, the frequency ratio of the front-stage magnetic levitation compressor to the rear-stage magnetic levitation compressor is 6:

5.

9. The method for collecting and pressurizing lean materials in a 1,000-ton uranium enrichment cascade according to claim 7, characterized in that: The medium flow rate of the inlet main pipeline is 60-75 g / s.

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