PSA nitrogen preparation and two-stage pressurization coordinated high-pressure nitrogen preparation system

Abstract

The application discloses a high-pressure nitrogen preparation system cooperating with two-stage pressurization of PSA nitrogen preparation, relates to the technical field of gas separation and pressurization, and comprises a screw air compressor unit, an air pretreatment unit, a PSA nitrogen preparation unit, a screw pressurization unit and a liquid-driven pressurization unit, wherein the screw air compressor unit, the air pretreatment unit, the PSA nitrogen preparation unit, the screw pressurization unit and the liquid-driven pressurization unit are sequentially connected in series through pipelines. The application optimizes the PSA nitrogen preparation timing through four pairs of adsorption towers, combines the two-stage pressurization mode of'screw pre-pressurization + liquid-driven final pressurization', realizes stable and efficient preparation of high-pressure nitrogen, and solves the problems of large pressure fluctuation of a traditional nitrogen preparation system, a large number of vulnerable parts of a pressurization system and vibration.

Description

Technical Field

[0001] This invention relates to the field of gas separation and pressurization technology, specifically to a high-pressure nitrogen preparation system that combines PSA nitrogen generation with two-stage pressurization. Background Technology

[0002] Pressure swing adsorption (PSA) nitrogen generation technology is widely used in industries such as chemical, petroleum, and electronics due to its advantages such as simple process flow, high degree of automation, and low operating cost. Traditional PSA nitrogen generation systems typically use two adsorption towers operating alternately, but this results in problems such as large pressure fluctuations and limited nitrogen production efficiency. Especially in scenarios where high-pressure nitrogen is required, a single booster device cannot balance the boosting ratio and operational stability.

[0003] In existing technologies, high-pressure nitrogen production often employs a combination of "PSA nitrogen generator + reciprocating booster," but this approach has the following drawbacks: First, the nitrogen production flow rate of traditional 2-tower PSA nitrogen generator systems fluctuates greatly, the nitrogen supply pressure is unstable, or a large-capacity buffer tank is required, resulting in an excessively large overall size of the equipment, which is not conducive to skid-mounted design and road transportation. Second, when the reciprocating booster achieves a high compression ratio (exhaust pressure above 50MPa), the equipment vibration problem urgently needs to be solved. In addition, there are also problems such as short lifespan of vulnerable parts such as piston rings and intake valves. Summary of the Invention

[0004] To address the shortcomings of the existing technologies, the present invention aims to provide a high-pressure nitrogen preparation system that combines PSA nitrogen generation with two-stage pressurization. By optimizing the PSA nitrogen generation sequence through four pairs of adsorption towers and combining a two-stage pressurization mode of "screw pre-pressurization + liquid-driven final pressurization", the system achieves stable and efficient preparation of high-pressure nitrogen, solving the problems of large pressure fluctuations, numerous vulnerable parts in the pressurization system, and vibration in traditional nitrogen generation systems.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A high-pressure nitrogen production system combining PSA nitrogen generation and two-stage pressurization includes a screw air compressor unit, an air pretreatment unit, a PSA nitrogen generation unit, a screw booster unit, and a liquid-driven booster unit, wherein the screw air compressor unit, air pretreatment unit, PSA nitrogen generation unit, screw booster unit, and liquid-driven booster unit are connected in series via pipelines. The screw air compressor unit includes five screw air compressors, four in use and one on standby; The air pretreatment unit includes an air-cooled precooler, a primary coarse filter, a secondary precision filter, a refrigerated dryer, a tertiary precision filter, a quaternary ultra-precision filter, an air flow meter, process piping, and valves, forming a skid with complete oil removal, water removal, and dust removal functions. The operation of the entire skid is automatically controlled by a control cabinet. The PSA nitrogen generation unit includes an air buffer tank, four pairs of nitrogen adsorption towers, a nitrogen buffer tank, programmable valves, measuring instruments, manual valves, and pipelines. The screw compressor unit includes a screw compressor head, a motor, and an electrical control cabinet; The liquid-driven booster unit includes a liquid-driven reciprocating compressor main unit, a hydraulic oil power system, a nitrogen cooler, pipelines, valve groups, and an instrument control system.

[0006] Preferably, the four pairs of nitrogen-generating adsorption towers are arranged in parallel and are put into operation in groups in sequence to achieve a highly efficient cycle of adsorption-nitrogen generation-pressure equalization-desorption. During any working sequence, only one pair of adsorption towers is in the pressure equalization state, while the other three pairs of adsorption towers are in the adsorption-nitrogen generation state.

[0007] Preferably, a pressure sensor is provided between the air pretreatment unit and the PSA nitrogen generation unit.

[0008] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The nitrogen production mode of four pairs of adsorption towers can obtain a large flow rate of nitrogen gas, while ensuring that the pressure fluctuation range can be reduced to ±0.05MPa. The length, width and height dimensions can be controlled within 12×3.2×3.4 meters, which can meet the road transportation needs of the nitrogen production skid.

[0009] (2) The hydraulic booster unit adopts a hydraulic power system, which avoids the reciprocating piston compressor structure that is prone to failure. It is economical. The booster ratio of the hydraulic booster can be adjusted in stages by adjusting the pressure of the hydraulic system. The adjustment accuracy is ±0.5MPa, which can meet the high pressure nitrogen pressure requirements of different users. The length, width and height can be controlled within 12.5×2.7×2.8 meters, which can meet the road transportation requirements of the nitrogen production skid.

[0010] (3) The hydraulic booster compressor works in conjunction with the screw booster compressor and the screw air compressor, and all of them achieve frequency conversion regulation control. The exhaust pressure range is highly adaptable and meets the working requirements under different injection pressure and discharge conditions. The exhaust pressure control range is 25-100MPa, and the flow rate adjustment range is 40%-100%. The application of the frequency converter enables the flow rate and pressure to be adjusted as needed. The overall system energy consumption is reduced by 20%-30% compared with the traditional scheme. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0012] Figure 1 This is a system process flow diagram of the present invention; Figure 2 This is a timing diagram of the PSA nitrogen generation unit of the present invention.

[0013] Explanation of reference numerals in the attached figures: 100 - Screw air compressor unit; 200 - Air pretreatment unit; 300 - PSA nitrogen generator unit; 400 - Screw booster unit; 500 - Hydraulic booster unit. Detailed Implementation

[0014] The invention will now be described in detail with reference to the accompanying drawings, by way of example. Obviously, the described embodiments are only some embodiments of the invention, and not all embodiments. Example

[0015] like Figure 1 As shown, this invention discloses a high-pressure nitrogen preparation system that combines PSA nitrogen generation with two-stage pressurization, including a screw air compressor unit 100, an air pretreatment unit 200, a PSA nitrogen generation unit 300, a screw booster unit 400, and a liquid-driven booster unit 500. The gas flows sequentially through the screw air compressor unit 100, the air pretreatment unit 200, the PSA nitrogen generation unit 300, the screw booster unit 400, and the liquid-driven booster unit 500. Each unit is connected in series through pipelines and equipped with an instrumentation and control system to form an integrated control system.

[0016] The screw air compressor unit 100 includes five screw air compressors, four in operation and one on standby; the technical parameters are as follows: rated displacement of 35m³ / min per unit, main motor power of 200kW, permanent magnet variable frequency, two-stage compression, oil injection lubrication, and exhaust pressure of 0.8MPa.

[0017] The air pretreatment unit 200 sequentially passes compressed air through an air-cooled precooler, a primary coarse filter, a secondary precision filter, a refrigerated dryer, a tertiary precision filter, a quaternary ultra-precision filter, an air flow meter, and an outlet valve. Additionally, it comprises a skid-mounted unit with complete oil, water, and dust removal functions, consisting of process piping and valves. The entire skid operates automatically via a control cabinet, requiring no human intervention. The pretreated compressed air meets the following technical parameters: dew point ≤ -40℃, oil content ≤ 0.01ppm, and particle size ≤ 0.01μm.

[0018] The PSA nitrogen generator unit 300 includes a 4m³ air buffer tank, four pairs of nitrogen adsorption towers, a 4m³ nitrogen buffer tank, programmable valves, measuring instruments, manual valves, and pipelines. It enables the flow of compressed air to produce high-purity nitrogen, and the entire unit is automatically controlled. The nitrogen generator unit's exhaust parameters are: nitrogen flow rate 3000 Nm³ / h, nitrogen purity 99.5%, and nitrogen pressure 0.6 MPa.

[0019] The screw booster unit 400 includes a screw compressor head, a motor, and an electrical control cabinet; the technical parameters are as follows: nominal volumetric flow rate 50 Nm³ / min, rated exhaust pressure 3.5 MPa, inlet pressure 0.55~0.6 MPa, processing medium nitrogen, and rated motor power 315 kW.

[0020] The hydraulically driven booster unit 500 includes a hydraulically driven reciprocating compressor main unit, a hydraulic oil power system, a nitrogen cooler, pipelines, valve groups, and an instrumentation and control system. Technical parameters are as follows: nominal volumetric flow rate 50 Nm³ / min, inlet pressure 2.5 MPa~3.5 MPa, maximum exhaust pressure 70 MPa, main motor power 250 kW*2 units, permanent magnet variable frequency, variable frequency start and operation.

[0021] like Figure 2 As shown, the four pairs of nitrogen adsorption towers are arranged in parallel and are put into operation in groups in sequence to achieve a highly efficient cycle of adsorption-nitrogen production-pressure equalization-desorption. During any working sequence, only one pair of adsorption towers is in pressure equalization state, while the other three pairs of adsorption towers are in adsorption-nitrogen production state, which can reduce the pressure fluctuation range to ±0.05MPa.

[0022] The screw turbocharger unit 400 pre-pressurizes the 0.6-0.8MPa nitrogen produced by the PSA nitrogen generator to 3-5MPa. The speed of the screw turbocharger is adjusted by the frequency converter to match the output flow rate with the gas production of the PSA nitrogen generator unit 300, providing a stable medium-pressure gas source for the liquid-driven turbocharger unit 500 and reducing the workload of the liquid-driven turbocharger. The liquid-driven turbocharger adopts a twin-cylinder parallel structure, three-stage compression, and a cooling system to control the temperature rise, achieving a high compression ratio output of 25-100MPa.

[0023] A pressure sensor is installed between the air pretreatment unit 200 and the PSA nitrogen generator unit 300. When the pretreated air pressure is lower than 0.6MPa, the screw air compressor automatically increases its frequency and operates; when the pressure is higher than 1.0MPa, the air compressor enters the unloading state.

[0024] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and application concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A high-pressure nitrogen production system combining PSA nitrogen generation and two-stage pressurization, characterized in that: The system includes a screw air compressor unit (100), an air pretreatment unit (200), a PSA nitrogen generator unit (300), a screw booster unit (400), and a liquid-driven booster unit (500), which are connected in series via pipelines. The screw air compressor unit (100) includes five screw air compressors, four in use and one on standby; The air pretreatment unit (200) includes an air-cooled precooler, a primary coarse filter, a secondary precision filter, a refrigerated dryer, a tertiary precision filter, a quaternary ultra-precision filter, an air flow meter, process pipes and valves, forming a skid with complete oil removal, water removal and dust removal functions. The operation of the entire skid is automatically controlled by the control cabinet. The PSA nitrogen generation unit (300) includes an air buffer tank, four pairs of nitrogen adsorption towers, a nitrogen buffer tank, a programmable valve, measuring instruments, a manual valve, and pipelines; The screw compressor unit (400) includes a screw compressor head, a motor, and an electrical control cabinet; The liquid-driven booster unit (500) includes a liquid-driven reciprocating compressor main unit, a hydraulic oil power system, a nitrogen cooler, pipelines, valve groups, and an instrument control system.

2. The high-pressure nitrogen production system with PSA nitrogen generation and two-stage pressurization synergy as described in claim 1, characterized in that: The four pairs of nitrogen-generating adsorption towers are arranged in parallel and are put into operation in groups in sequence to achieve a highly efficient cycle of adsorption-nitrogen generation-pressure equalization-desorption. During any working sequence, only one pair of adsorption towers is in the pressure equalization state, while the other three pairs of adsorption towers are in the adsorption-nitrogen generation state.

3. The high-pressure nitrogen production system with PSA nitrogen generation and two-stage pressurization synergy as described in claim 1, characterized in that: A pressure sensor is provided between the air pretreatment unit (200) and the PSA nitrogen generation unit (300).

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