Closed pipeline conventional liquid propellant treatment system and method

Abstract

The invention relates to a conventional liquid propellant treatment system and method, in particular to a closed pipeline conventional liquid propellant treatment system and method, and aims to solve the technical problem that in the prior art, liquid rocket propellants in a complex closed pipeline with a long and thin pipe and a blind cavity cannot be thoroughly treated. The system comprises a pressurization blowdown system which comprises a pressurization air source, a pressurization pipeline with one end connected with the pressurization air source and a first replacement isolation valve connected to the pressurization pipeline; the vacuum suction system comprises a buffer tank, a vacuum pump and a vacuum gauge, an inlet of the vacuum pump is connected with the buffer tank through a vacuum pump isolating valve, and the vacuum gauge is connected with the buffer tank through a vacuum gauge isolating valve; a vacuumizing isolation valve, a second replacement isolation valve and a buffer tank blow-down valve are further arranged on the buffer tank; an inlet of the neutralization treatment device is used for being connected with a discharge isolation valve or being simultaneously connected with an outlet of the vacuum pump and a blow-down valve of the buffer tank, and an outlet of the neutralization treatment device is used for being in butt joint with an exhaust port of a plant through a pipeline or led outdoors.

Description

Technical Field

[0001] The invention relates to a conventional liquid propellant processing system and method, and in particular to a closed-pipe conventional liquid propellant processing system and method. Background Art

[0002] Conventional liquid rocket propellants (hereinafter referred to as liquid propellants) are generally toxic, harmful, highly corrosive, flammable and explosive, making the treatment process of their residual liquid more difficult than other ordinary liquids.

[0003] For liquid rocket engines, the working principle is generally to store liquid propellant in a propellant tank, squeeze the propellant in the tank into a delivery pipeline by means of gas or fuel gas pressurization, and then transport it to the liquid engine inlet valve through the pipeline, and control the engine operation and shutdown by controlling the valve switch. After the engine is finished working, the general treatment method for the liquid propellant in the pipeline is to use the discharge process port to empty the liquid propellant in the pipeline, and then use nitrogen to blow away the residual propellant in the pipeline through the pipeline blowing process port. For the liquid propellant pipeline used for the test, the pipeline needs to be dismantled after blowing, neutralized and cleaned with cleaning fluid, dehydrated with industrial alcohol, and then blown dry with nitrogen for subsequent use or storage.

[0004] Figure 1 The figure shows a schematic diagram of the layout of a propellant pipeline of an existing typical conventional liquid power system. The propellant pipeline is connected between a propellant tank 1 and a liquid engine 5. A tank isolation valve 2 is provided between the propellant pipeline and the propellant tank 1. A treated pipeline blow-off process port 3 is provided at a position of the propellant pipeline close to the tank isolation valve 2. A treated pipeline discharge process port 4 is provided at a position of the propellant pipeline close to the liquid engine 5. A blow-off isolation valve is installed at the treated pipeline blow-off process port 3, and a discharge isolation valve is installed at the treated pipeline discharge process port 4.

[0005] However, for non-removable pipelines, especially for reusable liquid power systems, after the engine finishes working, on the one hand, the propellant in the pipeline needs to be emptied in order to conduct inspection and testing before the next reuse; on the other hand, the liquid propellant will react with air to produce excess or cause corrosion to the engine, so it is necessary to ensure that the pipeline is not in contact with air.

[0006] However, the spatial layout of the propellant delivery pipeline used in liquid engines is generally three-dimensional and complex. There are also throttling elements in the pipeline, and there are many blind cavities. Especially for closed pipelines with thin pipes (for example, the diameter is 1mm to 10mm) and long, it is more difficult to clean the propellant in the pipeline through existing processing methods due to many factors such as small diameter, long pipeline, complex structure, and blind cavity. Especially for reusable liquid power systems, in order to ensure safety during inspection and testing, the residual propellant liquid and even steam in the pipeline needs to be completely cleaned to ensure product and personnel safety. Summary of the invention

[0007] The purpose of the present invention is to solve the technical problem that it is difficult to cleanly process liquid rocket propellant in a closed pipeline with complex, slender pipes and blind cavities in the prior art, and to provide a closed pipeline conventional liquid propellant processing system and method.

[0008] The inventive concept of the present invention is: for liquid propellant in a closed pipeline, firstly, a nitrogen positive pressure extrusion method is adopted to blow out most of the residual liquid propellant in the pipeline; an intermittent blowing method is adopted during the blowing, that is, after blowing for a few minutes, the pipeline is pressurized and left to stand for a few minutes, and the nitrogen and propellant vapor in the pipeline are mixed by standing, and then the pipeline is blown for a few minutes to allow the nitrogen flow process to carry the residual vapor out, and this cycle is repeated until there is no liquid and obvious propellant vapor for subsequent treatment; due to the presence of a blind cavity in the pipeline, the residual propellant cannot be completely emptied by only using nitrogen blowing Liquid propellants all have a certain saturated vapor pressure. Under a vacuum state, the liquid propellant will continue to evaporate until the gas phase pressure reaches the saturated vapor pressure at its ambient temperature. The present invention utilizes the saturated vapor pressure of the liquid propellant and adopts a vacuum suction method to vacuum and empty the remaining liquid propellant, thereby realizing the treatment of the closed pipeline propellant and making it reusable; using a vacuum buffer tank, through a cyclic treatment method of vacuum suction → nitrogen blowing and replacement → vacuum suction, the efficiency of using the vacuum suction method to treat the liquid propellant in the pipeline is greatly improved.

[0009] In order to achieve the above-mentioned purpose and complete the above-mentioned inventive concept, the technical solution adopted by the present invention is:

[0010] A closed-channel conventional liquid propellant processing system, which is special in that it includes:

[0011] A pressurized blow-off system, comprising a pressurized gas source, a pressurized pipeline having one end connected to the pressurized gas source, and a first displacement isolation valve connected to the pressurized pipeline;

[0012] The vacuum suction system includes a buffer tank, a vacuum pump and a vacuum gauge. The inlet of the vacuum pump is connected to the buffer tank through a vacuum pump isolation valve, and the vacuum gauge is connected to the buffer tank through a vacuum gauge isolation valve. The buffer tank is also provided with a vacuum isolation valve, a second replacement isolation valve and a buffer tank drain valve. The vacuum isolation valve is used to be connected to a blow-off isolation valve at a blow-off process port of a treated pipeline or a discharge isolation valve at a discharge process port of a treated pipeline through a pipeline, the second replacement isolation valve is used to be connected to the other end of the booster pipeline, and the buffer tank drain valve is used to discharge the propellant in the buffer tank and replace the buffer tank.

[0013] The neutralization treatment device is provided with an air inlet valve of the neutralization treatment device at the inlet, and an exhaust valve of the neutralization treatment device is provided at the outlet. The inlet is used for connecting with the discharge isolation valve, or for connecting with the outlet of the vacuum pump and the sewage valve of the buffer tank at the same time, and the outlet is used for connecting with the exhaust port of the factory building by using a pipeline or leading to the outdoors.

[0014] Furthermore, the pressurized blowing system also includes a pressure detector and a pressure reducer; the pressure reducer and the pressure detector are sequentially connected to the pressurized pipeline along the air supply direction; the pressure detector is a pressure gauge or a pressure sensor.

[0015] Furthermore, the boost and blow-off system also includes a heating device, which is arranged on the boost pipeline and is used to heat the gas in the boost pipeline.

[0016] Further, a filter is connected between the vacuum pump isolation valve and the vacuum pump;

[0017] The vacuum pump adopts oil-free dry explosion-proof and corrosion-resistant screw vacuum pump;

[0018] The explosion-proof grade of the vacuum pump is not lower than ExdII BT4.

[0019] Further, the volume of the buffer tank is 10 to 30 times the volume of the treated pipeline, or the volume of the buffer tank is 10L to 30L, which is used for the treated pipeline with a volume less than 10L;

[0020] Alternatively, the volume of the buffer tank is 1 to 10 times the volume of the treated pipeline, or the volume of the buffer tank is 10L to 100L, and is used for treated pipelines with a volume greater than 10L.

[0021] Furthermore, the vacuum isolation valve is installed on the side wall of the buffer tank body, the vacuum gauge isolation valve, the second replacement isolation valve and the vacuum pump isolation valve are all installed on the top of the buffer tank body, and the buffer tank drain valve is installed on the bottom of the buffer tank body; the buffer tank is connected to the second replacement isolation valve through a diffusion tube; the upper end of the diffusion tube is connected to the second replacement isolation valve, the lower end of the diffusion tube is blocked and extends into the buffer tank body, and a plurality of through holes are provided on the outer periphery of the diffusion tube near the lower end, and the through holes connect the diffusion tube and the buffer tank.

[0022] At the same time, the present invention also provides a closed pipeline conventional liquid propellant processing method, which adopts the above-mentioned closed pipeline conventional liquid propellant processing system, and its special feature is that it includes the following steps:

[0023] S1. Pipeline connection

[0024] S1.1 Connect the other end of the booster pipe of the booster blowdown system to the blowdown isolation valve at the blowdown process port of the treated pipeline, and adjust the air supply pressure to the preset target value;

[0025] S1.2 Use a pipe to connect the inlet of the neutralization treatment device with the discharge isolation valve at the discharge process port of the treated pipeline, use a pipe to connect the outlet of the neutralization treatment device with the exhaust port of the plant or lead it to the outdoors, and open the exhaust valve of the neutralization treatment device to keep the neutralization treatment device vented;

[0026] S1.1 and S1.2 have no priority order and can be performed simultaneously or one after the other;

[0027] S2, Nitrogen replacement

[0028] Confirm that the blow-off isolation valve is closed;

[0029] Complete the following operations at least once: open the first replacement isolation valve, discharge nitrogen from the first replacement isolation valve through the boosting pipeline, replace the air in the boosting pipeline, and close the first replacement isolation valve after the first preset time;

[0030] S3. Pipeline Blowing

[0031] S3.1 Open the purge isolation valve to allow the purge nitrogen to enter the treated pipeline, and open the discharge isolation valve and the neutralization treatment device air inlet valve in sequence to allow the propellant liquid and steam in the treated pipeline to enter the neutralization treatment device and be discharged after neutralization reaction;

[0032] S3.2 The discharge isolation valve is repeatedly closed and opened at preset time intervals, and the treated pipeline is intermittently purged for a preset time to complete the purging of the treated pipeline;

[0033] S3.3. Close the discharge isolation valve, the blowdown isolation valve, the neutralization treatment device air inlet valve and the neutralization treatment device exhaust valve in sequence, and dismantle the boost blowdown system and the neutralization treatment device;

[0034] S4. Vacuum suction system connection

[0035] Connect the vacuum isolation valve of the buffer tank to the blowdown isolation valve through pipelines, connect the buffer tank drain valve and the outlet of the vacuum pump of the buffer tank to the air inlet valve of the neutralization treatment device through pipelines, connect the second replacement isolation valve of the buffer tank to the other end of the booster pipeline of the booster blowdown system, open the vacuum gauge isolation valve, the air inlet valve of the neutralization treatment device and the exhaust valve of the neutralization treatment device, confirm that the blowdown isolation valve, the discharge isolation valve, the vacuum isolation valve, the second replacement isolation valve, the vacuum pump isolation valve and the buffer tank drain valve are in the closed state, and start the vacuum pump;

[0036] S5. Vacuum treatment

[0037] S5.1: Open the vacuum pump isolation valve for a second preset time, and then observe whether the vacuum gauge reading is less than the first preset pressure value. If so, close the vacuum pump isolation valve and execute step S5.2. If not, execute step S5.3.

[0038] S5.2 Open the vacuum isolation valve, then open the purge isolation valve, so that the residual propellant vapor in the treated pipeline is sucked into the buffer tank. At this time, the vacuum gauge reading increases. After the third preset time, close the purge isolation valve, vacuum isolation valve, and vacuum gauge isolation valve, open the second replacement isolation valve and buffer tank drain valve, adjust the output pressure of the booster pipeline, purge and replace the buffer tank with nitrogen at the second preset pressure value for the fourth preset time, close the second replacement isolation valve and buffer tank drain valve, open the vacuum gauge isolation valve, and execute step S5.5;

[0039] S5.3 observe whether the vacuum gauge indication is less than the third preset pressure value. If so, close the vacuum pump isolation valve and execute step S5.2. If not, execute step S5.4. The third preset pressure value is greater than the first preset pressure value. The third preset pressure value is used to determine whether the vacuum pump can continue to work effectively due to the strong adsorption of the liquid propellant.

[0040] S5.4 confirms that the vacuum isolation valve is in the closed state, closes the vacuum gauge isolation valve, opens the second replacement isolation valve, adjusts the output pressure of the booster pipeline, and uses nitrogen of the fourth preset pressure value to blow and replace the buffer tank and the vacuum pump. After the fifth preset time, close the second replacement isolation valve, open the vacuum gauge isolation valve, and after the second preset time, observe whether the vacuum gauge indication is less than the first preset pressure value. If so, close the vacuum pump isolation valve and execute step S5.2. If not, repeat step S5.4 until the vacuum gauge indication is less than the first preset pressure value.

[0041] S5.5 After repeating step S5.1 at least once, execute step S6;

[0042] S6 switches the vacuum position and continues the vacuum process

[0043] S6.1 Confirm that the blow-off isolation valve is closed, remove the vacuum suction system from the blow-off isolation valve, and connect the vacuum isolation valve of the buffer tank to the discharge isolation valve through a pipeline;

[0044] S6.2 adopts the same method as step S5 to evacuate the treated pipeline to make the residual propellant in the blind cavity of the pipeline near the inlet of the liquid engine be drawn out more quickly;

[0045] S7, pressure maintenance

[0046] Open the vacuum pump isolation valve, evacuate until the vacuum gauge indication is lower than the first preset pressure value, then close the vacuum pump isolation valve, open the vacuum isolation valve and the discharge isolation valve, and after standing for the sixth preset time, observe whether the vacuum degree does not exceed the fifth preset pressure value through the vacuum gauge. If so, close the discharge isolation valve, the neutralization treatment device air inlet valve, the neutralization treatment device exhaust valve, the vacuum isolation valve, the vacuum gauge isolation valve and the vacuum pump, dismantle the vacuum suction system, and then execute step S8; if not, close the vacuum isolation valve and the discharge isolation valve and return to step S6.2, or close the discharge isolation valve, the neutralization treatment device air inlet valve, the neutralization treatment device exhaust valve, the vacuum isolation valve, the vacuum gauge isolation valve and the vacuum pump, dismantle the vacuum suction system, and then return to step S4;

[0047] S8, positive pressure sealing

[0048] The other end of the boosting pipeline of the boosting and blowing system is connected to the blowing isolation valve, and nitrogen replacement is performed using the same method as step S2. Then, the blowing isolation valve is opened to seal the treated pipeline, so that the pressure in the treated pipeline reaches a sixth preset pressure value. Finally, the blowing isolation valve is closed, the boosting and blowing system is dismantled, and the conventional liquid propellant treatment of the closed pipeline is completed.

[0049] Furthermore, in step S1, the air supply pressure is adjusted to a preset target value by adjusting the pressure reducer, and the preset target value is 0.3-0.5 MPa;

[0050] In step S2, the process is completed at least three times; the first preset time is not less than 1 minute;

[0051] Step S3.2 specifically includes: opening the discharge isolation valve for 3 to 5 minutes and closing it for 3 to 5 minutes, repeatedly closing and opening it, and intermittently blowing the treated pipeline for 15 to 30 minutes to complete the blowing of the treated pipeline;

[0052] In step S7, the sixth preset time is 3 minutes, and the fifth preset pressure value is 100 Pa;

[0053] In step S8, the sixth preset pressure value is 0.2-0.5 MPa.

[0054] Further, in step S5.1, the first preset pressure value is 10Pa, and the second preset time is 1 to 5 minutes;

[0055] In step S5.2, the third preset time is 1 to 3 minutes, the second preset pressure value is 0.3 to 0.5 MPa, and the fourth preset time is 1 to 3 minutes;

[0056] In step S5.3, the third preset pressure value is 50Pa;

[0057] In step S5.4, the fourth preset pressure value is 0.05-0.1 MPa, and the fifth preset time is 1-3 min;

[0058] Step S5.5 is specifically to repeat step S5.1 twice and then execute step S6.

[0059] Compared with the prior art, the present invention has the following beneficial technical effects:

[0060] 1. The conventional liquid propellant treatment system and method proposed in the present invention can clean the liquid propellant in the pipeline without contacting the air in the pipeline;

[0061] 2. The conventional liquid propellant treatment system and method proposed in the present invention effectively improves the treatment efficiency of residual liquid propellant in the pipeline by using a buffer tank;

[0062] 3. The conventional liquid propellant treatment system and method proposed in the present invention can be applied to the safe treatment of liquid propellants in pipelines of various specifications;

[0063] 4. The conventional liquid propellant treatment system and method proposed in the present invention can be applied to the clean treatment of reusable liquid power system pipelines;

[0064] 5. The conventional liquid propellant processing system proposed in the present invention realizes the safe processing of corrosive conventional liquid propellants by adopting an explosion-proof and corrosion-resistant screw vacuum pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 The following is a schematic diagram of the propellant pipeline layout of a typical conventional liquid power system (the blow-off isolation valve and the discharge isolation valve are not shown);

[0066] Figure 2 It is a schematic diagram of the use of a pressurized blow-off system in an embodiment of a closed-pipe conventional liquid propellant processing system of the present invention;

[0067] Figure 3 It is a schematic diagram of a vacuum suction system connected to a blow-off isolation valve in an embodiment of a closed pipeline conventional liquid propellant processing system of the present invention;

[0068] Figure 4 It is a schematic diagram of a vacuum suction system connected to a discharge isolation valve in an embodiment of a closed-pipe conventional liquid propellant processing system of the present invention;

[0069] Figure 5 It is a schematic diagram of the structure of a buffer tank in an embodiment of a closed pipeline conventional liquid propellant processing system of the present invention;

[0070] Figure 6 for Figure 5 The enlarged view of point A in the middle;

[0071] Figure 7 It is a schematic diagram of the cross-sectional structure of the diffusion pipe of the buffer tank in an embodiment of a closed pipeline conventional liquid propellant processing system of the present invention.

[0072] The following are the descriptions of the reference numerals:

[0073] 1-propellant tank, 2-tank isolation valve, 3-process port for blowing off the treated pipeline, 4-process port for discharging the treated pipeline, 5-liquid engine, 6-blowing off isolation valve, 7-first replacement isolation valve, 8-pressure detector, 9-pressure reducer, 10-discharge isolation valve, 11-neutralization treatment device, 12-neutralization treatment device air inlet valve, 13-neutralization treatment device exhaust valve, 14-buffer tank, 141-diffusion pipe, 142-through hole, 15-vacuum isolation valve, 16-vacuum gauge, 17-vacuum gauge isolation valve, 18 second replacement isolation valve, 19-vacuum pump isolation valve, 20-buffer tank drain valve, 21-filter, 22-vacuum pump. DETAILED DESCRIPTION

[0074] In order to make the purpose, advantages and features of the present invention more clear, a closed-pipe conventional liquid propellant processing system and method proposed by the present invention are further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0075] In the description of the present invention, it should be noted that the terms “first” and “second” are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0076] Figure 1 What is shown is a schematic diagram of the layout of the propellant pipeline of an existing typical conventional liquid power system. The propellant pipeline is connected between the propellant tank 1 and the liquid engine 5. A tank isolation valve 2 is arranged between the propellant pipeline and the propellant tank 1. A treated pipeline blow-off process port 3 is arranged on one end of the propellant pipeline close to the tank isolation valve 2. A treated pipeline discharge process port 4 is arranged on one end of the propellant pipeline close to the liquid engine 5. A blow-off isolation valve is installed at the treated pipeline blow-off process port 3, and a discharge isolation valve is installed at the treated pipeline discharge process port 4. The blow-off isolation valve and the discharge isolation valve are both in a closed state when not working.

[0077] like Figure 2 and Figure 3 As shown, a closed-pipe conventional liquid propellant processing system of this embodiment includes a pressurized blowing system, a vacuum suction system and a neutralization processing device 11.

[0078] like Figure 2 As shown, the boosting and blowing system includes a boosting gas source, a boosting pipeline, a pressure detector 8, a pressure reducer 9 and a first displacement isolation valve 7. The boosting gas source is used to provide nitrogen. One end of the boosting pipeline is connected to the boosting gas source. The pressure reducer 9, the pressure detector 8 and the first displacement isolation valve 7 are connected to the boosting pipeline in sequence along the gas supply direction. The pressure reducer 9 is used to adjust the output pressure of the boosting pipeline. The pressure detector 8 is a pressure gauge.

[0079] In other embodiments, the pressure detector 8 may also be a pressure sensor.

[0080] In other embodiments, under necessary conditions, the boosting and blowing system also includes a heating device, which is arranged on the boosting pipeline. The heating device is used to heat the gas in the boosting pipeline. The hot nitrogen blowing can increase the steam temperature in the pipeline, increase the saturated vapor pressure of the propellant, and improve the processing efficiency.

[0081] like Figure 3 and Figure 4 As shown, the vacuum pumping system includes a buffer tank 14 , a vacuum pump 22 , and a vacuum gauge 16 .

[0082] The buffer tank 14 is used for pipeline vacuum buffering. For a processed pipeline with a volume less than 10L, the volume of the buffer tank 14 is 10 to 30 times the volume of the processed pipeline, or the volume of the buffer tank 14 is 10L to 30L; for a processed pipeline with a volume greater than 10L, the volume of the buffer tank 14 is 1 to 10 times the volume of the processed pipeline, or the volume of the buffer tank 14 is 10L to 100L.

[0083] The buffer tank 14 is provided with a vacuum isolation valve 15, a vacuum gauge isolation valve 17, a second replacement isolation valve 18, a vacuum pump isolation valve 19 and a buffer tank drain valve 20; the vacuum pump isolation valve 19 is installed on the top of the buffer tank 14 tank body, and the vacuum pump isolation valve 19 is used to isolate the vacuum pump 22. The inlet of the vacuum pump 22 is connected to the buffer tank 14 through the vacuum pump isolation valve 19, and a filter 21 is connected between the vacuum pump isolation valve 19 and the vacuum pump 22. The setting of the filter 21 can prevent excess materials from being sucked into the vacuum pump 22 during the vacuum extraction process to cause a malfunction; the vacuum gauge isolation valve 17 is installed on the top of the buffer tank 14 tank body, and the vacuum gauge 16 is connected to the buffer tank 14 through the vacuum gauge isolation valve 17. When vacuuming, the vacuum gauge isolation valve 17 is opened to connect the vacuum gauge 16 with the buffer tank 14 to measure the vacuum degree, when the buffer tank 14 is replaced by nitrogen blowing, the vacuum gauge isolation valve 17 is closed to protect the vacuum gauge 16 from positive pressure; the vacuum isolation valve 15 is installed on the side wall of the buffer tank 14 tank body, and the vacuum isolation valve 15 is used to be connected to the blow-off isolation valve 6 at the blow-off process port 3 of the treated pipeline or the discharge isolation valve 10 at the discharge process port 4 of the treated pipeline through a pipeline, and the vacuum isolation valve 15 is used to isolate the pumped pipeline; the second replacement isolation valve 18 is installed on the top of the buffer tank 14 tank body, and the second replacement isolation valve 18 is used to be connected to the other end of the boosting pipeline, and the second replacement isolation valve 18 is used to replace the buffer tank 14 with nitrogen; the buffer tank drain valve 20 is installed at the bottom of the buffer tank 14 tank body, and the buffer tank drain valve 20 is used to discharge the propellant in the buffer tank 14 and replace the buffer tank 14.

[0084] like Figure 3 , Figure 5 , Figure 6 , Figure 7 As shown, the buffer tank 14 is connected to the second replacement isolation valve 18 through a diffuser 141, the upper end of the diffuser 141 is connected to the second replacement isolation valve 18, the lower end of the diffuser 141 is blocked and extends into the buffer tank 14, and a plurality of through holes 142 are provided on the outer periphery near the lower end of the diffuser 141, and the through holes 142 connect the diffuser 141 and the buffer tank 14. Specifically, four circles of through holes 142 are provided on the outer periphery near the lower end of the diffuser 141 along the axial direction of the diffuser 141, and each circle of through holes 142 includes six through holes 142. The six through holes 142 in the same circle are evenly distributed around the axis of the diffuser 141, and the axis of the through holes 142 extends along the radial direction of the diffuser 141. The propellant has a certain adsorption capacity, especially hydrazine fuel, which has strong adsorption capacity. When gas blowing is not used, it adheres to the wall of the buffer tank 14 and requires a longer time to be sucked out. The use of a diffusion tube method can make the blowing gas evenly blow to the inner wall of the buffer tank 14, thereby improving the blowing and replacement efficiency.

[0085] The vacuum pump 22 adopts an oil-free dry explosion-proof and corrosion-resistant screw vacuum pump. The explosion-proof level of the vacuum pump 22 meets the corresponding explosion-proof level of the propellant to be processed, which is generally not lower than ExdII BT4; the screw pump has the advantages of being able to adapt to harsh working conditions, having the ability to extract condensable and particulate gases, and being easy to be treated with corrosion protection; the oil-free dry pump can prevent oil pollution from polluting the pumped pipeline; corrosion resistance can effectively prevent the propellant from corroding the gas-contacting part of the pump body, reduce pump body failures, and improve the reliability and safety of pump operation.

[0086] The vacuum gauge 16 is used to measure the vacuum degree at the buffer tank 14, and its measuring range should cover 0Pa to 100kPa, so as to facilitate the detection of the vacuum pumping process and assist in determining the effect of residual propellant treatment.

[0087] The neutralization treatment device 11 is used to neutralize liquid propellant, and is generally a container containing neutralization liquid. A neutralization treatment device air inlet valve 12 is provided at the inlet of the neutralization treatment device 11, and a neutralization treatment device exhaust valve 13 is provided at the outlet of the neutralization treatment device 11. The inlet of the neutralization treatment device 11 is used to be connected to the discharge isolation valve 10, or to be connected to the outlet of the vacuum pump 22 and the buffer tank drain valve 20 at the same time, and the outlet of the neutralization treatment device 11 is used to connect with the exhaust port of the factory building using a pipeline or lead to the outdoors.

[0088] A closed-pipe conventional liquid propellant processing method of this embodiment adopts the above-mentioned closed-pipe conventional liquid propellant processing system, and includes the following steps:

[0089] S1. Pipeline connection

[0090] S1.1 Connect the other end of the booster pipeline of the booster blowdown system to the blowdown isolation valve 6 at the blowdown process port 3 of the treated pipeline, and adjust the air supply pressure to the preset target value by adjusting the pressure reducer 9. The preset target value is 0.3-0.5MPa;

[0091] S1.2 Use a pipeline to connect the inlet of the neutralization treatment device 11 with the discharge isolation valve 10 at the process outlet 4 of the treated pipeline, use a pipeline to connect the outlet of the neutralization treatment device 11 with the exhaust port of the factory building or lead it to an open area outside the factory building, and open the exhaust valve 13 of the neutralization treatment device to keep the neutralization treatment device 11 vented;

[0092] S1.1 and S1.2 have no priority order and can be performed simultaneously or one after the other;

[0093] S2, Nitrogen replacement

[0094] Confirm that the blow-off isolation valve 6 is closed;

[0095] Complete the following operations at least three times: open the first replacement isolation valve 7, discharge nitrogen from the first replacement isolation valve 7 through the boosting pipeline, replace the air in the boosting pipeline, open the first replacement isolation valve 7 for no less than 1 minute, and then close the first replacement isolation valve 7;

[0096] By performing nitrogen replacement on the booster pipeline in step S2, air can be prevented from entering the treated pipeline;

[0097] S3. Pipeline Blowing

[0098] S3.1 Open the purge isolation valve 6 to allow the purge nitrogen to enter the treated pipeline, and open the discharge isolation valve 10 and the neutralization treatment device air inlet valve 12 in sequence to allow the propellant liquid and steam in the treated pipeline to enter the neutralization treatment device 11 and be discharged after neutralization reaction;

[0099] S3.2 The discharge isolation valve 10 is repeatedly closed and opened at intervals of 3 to 5 minutes, and the treated pipeline is intermittently purged for 15 to 30 minutes to complete the purging of the treated pipeline;

[0100] S3.3 Close the discharge isolation valve 10, the blowdown isolation valve 6, the neutralization treatment device air inlet valve 12 and the neutralization treatment device exhaust valve 13 in sequence, and dismantle the boost blowdown system and the neutralization treatment device 11;

[0101] In step S3.1, the treated pipeline is blown out by nitrogen positive pressure extrusion, and most of the residual liquid propellant in the treated pipeline can be blown out; in step S3.2, the discharge isolation valve 10 is closed, and the treated pipeline is pressurized and left to stand for several minutes. The nitrogen and propellant vapor in the pipeline are mixed by standing, and the residual vapor is easily discharged during the subsequent blowing process of opening the discharge isolation valve 10 for several minutes. In addition, the pipeline is pressurized, and at the moment of opening the discharge isolation valve 10, the gas flows out quickly from the static state, which is easy to carry the propellant and vapor out; most of the residual propellant in the treated pipeline can be blown out by step S3;

[0102] S4. Vacuum suction system connection

[0103] Connect the vacuum isolation valve 15 of the buffer tank 14 to the blowdown isolation valve 6 through a pipeline, connect the outlets of the buffer tank drain valve 20 and the vacuum pump 22 of the buffer tank 14 to the air inlet valve 12 of the neutralization treatment device through pipelines, connect the second replacement isolation valve 18 of the buffer tank 14 to the other end of the booster pipeline of the booster blowdown system, make the vacuum gauge isolation valve 17, the air inlet valve 12 of the neutralization treatment device and the exhaust valve 13 of the neutralization treatment device in an open state, confirm that the blowdown isolation valve 6, the discharge isolation valve 10, the vacuum isolation valve 15, the second replacement isolation valve 18, the vacuum pump isolation valve 19 and the buffer tank drain valve 20 are in a closed state, and start the vacuum pump 22;

[0104] S5. Vacuum treatment

[0105] S5.1 Open the vacuum pump isolation valve 19 for 1 to 5 minutes, and then observe whether the reading of the vacuum gauge 16 is less than 10Pa. If so, close the vacuum pump isolation valve 19 and execute step S5.2. If not, execute step S5.3.

[0106] S5.2 Open the vacuum isolation valve 15, then open the purge isolation valve 6, so that the residual propellant vapor in the treated pipeline is sucked into the buffer tank 14. At this time, the indication of the vacuum gauge 16 increases. After 1 to 3 minutes, close the purge isolation valve 6, the vacuum isolation valve 15, and the vacuum gauge isolation valve 17, open the second replacement isolation valve 18 and the buffer tank drain valve 20, adjust the pressure reducer 9, purge and replace the buffer tank 14 with 0.3 to 0.5 MPa nitrogen for 1 to 3 minutes, close the second replacement isolation valve 18 and the buffer tank drain valve 20, open the vacuum gauge isolation valve 17, and execute step S5.5;

[0107] S5.3 Observe whether the indication of the vacuum gauge 16 is less than 50Pa. If so, close the vacuum pump isolation valve 19 and execute step S5.2. If not, execute step S5.4.

[0108] S5.4 Confirm that the vacuum isolation valve 15 is in the closed state, close the vacuum gauge isolation valve 17, open the second replacement isolation valve 18, adjust the pressure reducer 9, use 0.05-0.1MPa nitrogen to blow and replace the buffer tank 14 and the vacuum pump 22 for 1-3 minutes, close the second replacement isolation valve 18, open the vacuum gauge isolation valve 17, and continue for 1-5 minutes to observe whether the vacuum gauge 16 reading is less than 10Pa. If so, close the vacuum pump isolation valve 19 and execute step S5.2. If not, repeat step S5.4 until the vacuum gauge 16 reading is less than 10Pa;

[0109] S5.5 After repeating step S5.1 twice, execute step S6;

[0110] The strong adsorption of liquid propellant will reduce the vacuuming efficiency of the vacuum pump 22. By blowing and replacing the buffer tank 14 and the vacuum pump 22 in steps S5.3 and 5.4, the vacuuming efficiency of the vacuum pump 22 can be improved. After completing step S5, there is basically no residual propellant liquid in the treated pipeline.

[0111] S6 switches the vacuum position and continues the vacuum process

[0112] S6.1 Confirm that the blow-off isolation valve 6 is closed, remove the vacuum suction system from the blow-off isolation valve 6, and connect the vacuum isolation valve 15 of the buffer tank 14 with the discharge isolation valve 10 through a pipeline;

[0113] S6.2 Continue vacuuming

[0114] S6.2.1 Open the vacuum pump isolation valve 19 for 1 to 5 minutes, and then observe whether the reading of the vacuum gauge 16 is less than 10 Pa. If so, close the vacuum pump isolation valve 19 and execute step S6.2.2. If not, execute step S6.2.3.

[0115] S6.2.2 Open the vacuum isolation valve 15, and then open the discharge isolation valve 10, so that the residual propellant vapor in the treated pipeline is sucked into the buffer tank 14. At this time, the indication of the vacuum gauge 16 increases. After 1 to 3 minutes, close the discharge isolation valve 10, the vacuum isolation valve 15, and the vacuum gauge isolation valve 17, open the second replacement isolation valve 18 and the buffer tank drain valve 20, adjust the pressure reducer 9, and blow and replace the buffer tank 14 with 0.3 to 0.5 MPa nitrogen for 1 to 3 minutes, then close the second replacement isolation valve 18 and the buffer tank drain valve 20, open the vacuum gauge isolation valve 17, and execute step S6.2.5;

[0116] S6.2.3 Observe whether the indication of the vacuum gauge 16 is less than 50Pa. If so, close the vacuum pump isolation valve 19 and execute step S6.2.2. If not, execute step S6.2.4.

[0117] S6.2.4 Confirm that the vacuum isolation valve 15 is in the closed state, close the vacuum gauge isolation valve 17, open the second replacement isolation valve 18, adjust the pressure reducer 9, use 0.05-0.1MPa nitrogen to blow and replace the buffer tank 14 and the vacuum pump 22 for 1-3 minutes, close the second replacement isolation valve 18, open the vacuum gauge isolation valve 17, and continue for 1-5 minutes to observe whether the vacuum gauge 16 reading is less than 10Pa. If so, close the vacuum pump isolation valve 19 and execute step S6.2.2. If not, repeat step S6.2.4 until the vacuum gauge 16 reading is less than 10Pa;

[0118] S6.2.5 After repeating step S6.2.1 twice, proceed to step S7;

[0119] Step S6: vacuumizing the processed pipeline to more quickly extract the residual propellant in the blind cavity of the pipeline near the inlet of the liquid engine 5;

[0120] S7, pressure maintenance

[0121] Open the vacuum pump isolation valve 19, evacuate until the vacuum gauge 16 indicates a value lower than 10Pa, then close the vacuum pump isolation valve 19, open the vacuum isolation valve 15 and the discharge isolation valve 10, and after standing for 3 minutes, observe whether the vacuum degree does not exceed 100Pa through the vacuum gauge 16. If so, and the vacuum degree rises slowly, the treated pipeline has been vacuumed and cleaned, close the discharge isolation valve 10, the neutralization treatment device air inlet valve 12, the neutralization treatment device exhaust valve 13, the vacuum isolation valve 15, the vacuum gauge isolation valve 17 and the vacuum pump 22, dismantle the vacuum suction system, and then execute step S8; if not, close the vacuum isolation valve 15 and the discharge isolation valve 10 and return to step S6.2, or close the discharge isolation valve 10, the neutralization treatment device air inlet valve 12, the neutralization treatment device exhaust valve 13, the vacuum isolation valve 15, the vacuum gauge isolation valve 17 and the vacuum pump 22, dismantle the vacuum suction system, and then return to step S4;

[0122] S8, positive pressure sealing

[0123] The other end of the boosting pipeline of the boosting and blowing system is connected to the blowing isolation valve 6, and nitrogen replacement is performed in the same way as step S2, and then the blowing isolation valve 6 is opened to seal the treated pipeline, so that the pressure in the treated pipeline reaches 0.2-0.5 MPa, and finally the blowing isolation valve 6 is closed, the boosting and blowing system is removed, and the conventional liquid propellant treatment of the closed pipeline is completed. The treated pipeline is sealed at positive pressure in step S8, which can prevent a small amount of air from leaking into the pipeline after the propellant pipeline is vacuumed.

[0124] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the specific technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present invention.

Claims

1. A closed pipeline conventional liquid propellant processing system, characterized in that: include: The pressurized blowing system comprises a pressurized gas source, a pressurized pipeline having one end connected to the pressurized gas source, and a first displacement isolation valve (7) connected to the pressurized pipeline; A vacuum suction system comprises a buffer tank (14), a vacuum pump (22) and a vacuum gauge (16); the inlet of the vacuum pump (22) is connected to the buffer tank (14) through a vacuum pump isolation valve (19); the vacuum gauge (16) is connected to the buffer tank (14) through a vacuum gauge isolation valve (17); the buffer tank (14) is also provided with a vacuum isolation valve (15), a second replacement isolation valve (18) and a buffer tank drain valve (20); the vacuum isolation valve (15) is used to be connected to a blow-off isolation valve (6) at a blow-off process port (3) of a treated pipeline or a discharge isolation valve (10) at a discharge process port (4) of a treated pipeline through a pipeline; the second replacement isolation valve (18) is used to be connected to the other end of the boosting pipeline; the buffer tank drain valve (20) is used to discharge the propellant in the buffer tank (14) and replace the buffer tank (14); A neutralization treatment device (11) is provided with a neutralization treatment device air inlet valve (12) at its inlet and a neutralization treatment device air exhaust valve (13) at its outlet. The inlet is used to be connected to a discharge isolation valve (10), or to be connected to the outlet of a vacuum pump (22) and a buffer tank drain valve (20) at the same time. The outlet is used to be connected to a factory exhaust port using a pipeline or to be led to the outdoors.

2. The closed-channel conventional liquid propellant processing system according to claim 1, characterized in that: The pressurized blowing system also includes a pressure detector (8) and a pressure reducer (9); The pressure reducer (9) and the pressure detector (8) are sequentially connected to the boosting pipeline along the gas supply direction; The pressure detector (8) is a pressure gauge or a pressure sensor.

3. The closed-channel conventional liquid propellant processing system according to claim 2, characterized in that: The boosting and blowing system further comprises a heating device, which is arranged on the boosting pipeline and is used to heat the gas in the boosting pipeline.

4. The closed-channel conventional liquid propellant processing system according to claim 1, characterized in that: A filter (21) is connected between the vacuum pump isolation valve (19) and the vacuum pump (22); The vacuum pump (22) is an oil-free dry explosion-proof and corrosion-resistant screw vacuum pump; The explosion-proof grade of the vacuum pump (22) is not lower than ExdIIBT4.

5. The closed-channel conventional liquid propellant processing system according to claim 1, characterized in that: The volume of the buffer tank (14) is 10 to 30 times the volume of the treated pipeline, or the volume of the buffer tank (14) is 10L to 30L, and is used for the treated pipeline with a volume less than 10L; Alternatively, the volume of the buffer tank (14) is 1 to 10 times the volume of the pipeline to be treated, or the volume of the buffer tank (14) is 10L to 100L, and is used for pipelines to be treated with a volume greater than 10L.

6. The closed-channel conventional liquid propellant processing system according to claim 1, characterized in that: The vacuum isolation valve (15) is installed on the side wall of the buffer tank (14), the vacuum gauge isolation valve (17), the second replacement isolation valve (18) and the vacuum pump isolation valve (19) are all installed on the top of the buffer tank (14), and the buffer tank drain valve (20) is installed on the bottom of the buffer tank (14); The buffer tank (14) is connected to the second displacement isolation valve (18) via a diffusion pipe (141); The upper end of the diffusion pipe (141) is connected to the second displacement isolation valve (18), the lower end of the diffusion pipe (141) is blocked and extends into the tank body of the buffer tank (14), and a plurality of through holes (142) are provided on the outer periphery of the diffusion pipe (141) near the lower end, and the through holes (142) connect the diffusion pipe (141) and the buffer tank (14).

7. A method for processing conventional liquid propellants in a closed pipeline, characterized in that: A closed-pipe conventional liquid propellant processing system according to any one of claims 1 to 6 comprises the following steps: S1. Pipeline connection S1.1 Connect the other end of the booster pipeline of the booster blowdown system to the blowdown isolation valve (6) at the blowdown process port (3) of the treated pipeline, and adjust the air supply pressure to a preset target value; S1.2 Connect the inlet of the neutralization treatment device (11) to the discharge isolation valve (10) at the discharge process port (4) of the treated pipeline through a pipeline, connect the outlet of the neutralization treatment device (11) to the exhaust port of the plant through a pipeline or lead it to the outdoors, and open the exhaust valve (13) of the neutralization treatment device to keep the neutralization treatment device (11) vented; S1.1 and S1.2 have no priority order and can be performed simultaneously or one after the other; S2, Nitrogen replacement Confirm that the purge isolation valve (6) is closed; The following operations are performed at least once: opening the first replacement isolation valve (7) to allow nitrogen to be discharged from the first replacement isolation valve (7) through the boosting pipeline to replace the air in the boosting pipeline, and after a first preset time, closing the first replacement isolation valve (7); S3. Pipeline Blowing S3.1 Open the purge isolation valve (6) to allow the purge nitrogen to enter the treated pipeline, and then open the discharge isolation valve (10) and the neutralization treatment device air inlet valve (12) in sequence to allow the propellant liquid and steam in the treated pipeline to enter the neutralization treatment device (11) and be discharged after neutralization reaction; S3.2 repeatedly closing and opening the discharge isolation valve (10) at preset time intervals, intermittently blowing the treated pipeline for a preset time, and completing blowing the treated pipeline; S3.

3. Close the discharge isolation valve (10), the blowdown isolation valve (6), the neutralization treatment device air inlet valve (12) and the neutralization treatment device air outlet valve (13) in sequence, and dismantle the boost blowdown system and the neutralization treatment device (11); S4. Vacuum suction system connection The vacuum isolation valve (15) of the buffer tank (14) is connected to the blowdown isolation valve (6) through a pipeline, and the outlets of the buffer tank drain valve (20) and the vacuum pump (22) of the buffer tank (14) are connected to the neutralization treatment device air inlet valve (12) through pipelines. The second replacement isolation valve (18) of the buffer tank (14) is connected to the other end of the boost pipeline of the boost blowdown system, and the vacuum gauge isolation valve (17), the neutralization treatment device air inlet valve (12) and the neutralization treatment device exhaust valve (13) are in an open state. Confirm that the blowdown isolation valve (6), the exhaust isolation valve (10), the vacuum isolation valve (15), the second replacement isolation valve (18), the vacuum pump isolation valve (19) and the buffer tank drain valve (20) are in a closed state, and start the vacuum pump (22); S5. Vacuum treatment S5.1: Open the vacuum pump isolation valve (19) for a second preset time, and then observe whether the value indicated by the vacuum gauge (16) is less than the first preset pressure value. If so, close the vacuum pump isolation valve (19) and execute step S5.

2. If not, execute step S5.

3. S5.2: Open the vacuum isolation valve (15), then open the purge isolation valve (6), so that the residual propellant vapor in the treated pipeline is sucked into the buffer tank (14). At this time, the indication of the vacuum gauge (16) increases. After the third preset time, close the purge isolation valve (6), the vacuum isolation valve (15), and the vacuum gauge isolation valve (17), open the second replacement isolation valve (18) and the buffer tank drain valve (20), adjust the output pressure of the booster pipeline, purge and replace the buffer tank (14) with nitrogen of the second preset pressure value for the fourth preset time, close the second replacement isolation valve (18) and the buffer tank drain valve (20), open the vacuum gauge isolation valve (17), and execute step S5.5; S5.3 observing whether the indication of the vacuum gauge (16) is less than a third preset pressure value; if so, closing the vacuum pump isolation valve (19) and executing step S5.2; if not, executing step S5.4; the third preset pressure value is greater than the first preset pressure value, and the third preset pressure value is used to determine whether the vacuum pump (22) can continue to work effectively due to the strong adsorption of the liquid propellant; S5.4 confirms that the vacuum isolation valve (15) is in a closed state, closes the vacuum gauge isolation valve (17), opens the second replacement isolation valve (18), adjusts the output pressure of the booster pipeline, and uses nitrogen of a fourth preset pressure value to blow out and replace the buffer tank (14) and the vacuum pump (22). After a fifth preset time, close the second replacement isolation valve (18), open the vacuum gauge isolation valve (17), and after a second preset time, observe whether the vacuum gauge (16) reading is less than the first preset pressure value. If so, close the vacuum pump isolation valve (19) and execute step S5.

2. If not, repeat step S5.4 until the vacuum gauge (16) reading is less than the first preset pressure value. S5.5 After repeating step S5.1 at least once, execute step S6; S6 switches the vacuum position and continues the vacuum process S6.1 Confirm that the blow-off isolation valve (6) is closed, remove the vacuum suction system from the blow-off isolation valve (6), and connect the vacuum isolation valve (15) of the buffer tank (14) to the discharge isolation valve (10) through a pipeline; S6.2 adopts the same method as step S5 to evacuate the treated pipe, so that the residual propellant in the blind cavity of the pipe near the inlet of the liquid engine (5) can be extracted more quickly; S7, pressure maintenance Open the vacuum pump isolation valve (19), evacuate until the vacuum gauge (16) indicates a value lower than the first preset pressure value, then close the vacuum pump isolation valve (19), open the vacuum isolation valve (15) and the discharge isolation valve (10), and after standing for a sixth preset time, observe whether the vacuum degree does not exceed the fifth preset pressure value through the vacuum gauge (16). If so, close the discharge isolation valve (10), the neutralization treatment device air inlet valve (12), the neutralization treatment device exhaust valve (13), the vacuum isolation valve (15), the vacuum gauge isolation valve (17) and the vacuum pump (22), dismantle the vacuum suction system, and then execute step S8; if not, close the vacuum isolation valve (15) and the discharge isolation valve (10) and return to step S6.2, or close the discharge isolation valve (10), the neutralization treatment device air inlet valve (12), the neutralization treatment device exhaust valve (13), the vacuum isolation valve (15), the vacuum gauge isolation valve (17) and the vacuum pump (22), dismantle the vacuum suction system, and then return to step S4; S8, positive pressure sealing The other end of the boosting pipeline of the boosting and blowing system is connected to the blowing isolation valve (6), and nitrogen replacement is performed using the same method as step S2. Then, the blowing isolation valve (6) is opened to seal the treated pipeline, so that the pressure in the treated pipeline reaches a sixth preset pressure value. Finally, the blowing isolation valve (6) is closed, the boosting and blowing system is dismantled, and the conventional liquid propellant treatment of the closed pipeline is completed.

8. The closed-channel conventional liquid propellant processing method according to claim 7, characterized in that: In step S1, the air supply pressure is adjusted to a preset target value by adjusting the pressure reducer (9), wherein the preset target value is 0.3-0.5 MPa; In step S2, the process is completed at least three times; the first preset time is not less than 1 minute; Step S3.2 specifically comprises: opening the discharge isolation valve (10) at intervals of 3 to 5 minutes and closing it at intervals of 3 to 5 minutes, repeatedly closing and opening it, and intermittently blowing the treated pipeline for 15 to 30 minutes to complete blowing the treated pipeline; In step S7, the sixth preset time is 3 minutes, and the fifth preset pressure value is 100 Pa; In step S8, the sixth preset pressure value is 0.2-0.5 MPa.

9. The closed-channel conventional liquid propellant processing method according to claim 7, characterized in that: In step S5.1, the first preset pressure value is 10 Pa, and the second preset time is 1 to 5 minutes; In step S5.2, the third preset time is 1 to 3 minutes, the second preset pressure value is 0.3 to 0.5 MPa, and the fourth preset time is 1 to 3 minutes; In step S5.3, the third preset pressure value is 50Pa; In step S5.4, the fourth preset pressure value is 0.05-0.1 MPa, and the fifth preset time is 1-3 min; Step S5.5 is specifically to repeat step S5.1 twice and then execute step S6.

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