High-purity nitrogen preparation device for chip protection

Abstract

The utility model discloses a high-purity nitrogen preparation device for chip protection. The high-purity nitrogen preparation device comprises a raw material liquid nitrogen tank, a main heat exchanger, a rectifying tower, a main condensation evaporator, a subcooler, a nitrogen compressor, an aftercooler, a low-purity liquid nitrogen tank and a high-purity liquid nitrogen tank. According to the device, a high-purity nitrogen product of which the purity is less than or equal to 3ppmAr can be obtained by adopting a single-tower single-condensation rectification purification process, the requirements of a new chip production process are met (the Ar content of the nitrogen product is required to be controlled below 3ppm), and the device is simple in process flow, high in extraction rate and convenient to operate.

Description

Technical Field

[0001] The utility model relates to the technical field of air separation, in particular to a high-purity nitrogen preparation device for chip protection. Background Art

[0002] During the chip manufacturing and production process, high-quality nitrogen is needed for atmosphere protection and cleaning to ensure its quality and performance. With the development of chip technology, the quality requirements for the protective nitrogen used are also improved accordingly. At present, most chip manufacturers purchase liquid nitrogen and then vaporize it to produce nitrogen as a product. The argon (Ar) content of this nitrogen product is relatively high, generally above 1000ppm, while the new chip production process requires the Ar content to be controlled below 3ppm, which poses new challenges to the production of nitrogen products. Utility Model Content

[0003] The utility model aims to provide a high-purity nitrogen preparation device for chip protection to solve the shortcomings of the prior art.

[0004] The utility model adopts the following technical solutions:

[0005] A high-purity nitrogen production device for chip protection, comprising a raw material liquid nitrogen tank, a main heat exchanger, a distillation tower, a main condenser evaporator, a subcooler, a nitrogen compressor, an aftercooler, a low-purity liquid nitrogen tank and a high-purity liquid nitrogen tank;

[0006] The raw material liquid nitrogen tank, nitrogen compressor, aftercooler, low-purity liquid nitrogen tank and high-purity liquid nitrogen tank are located outside the cold box, the main heat exchanger, distillation tower, main condenser evaporator and subcooler are located inside the cold box, and the main condenser evaporator is located above the distillation tower;

[0007] The raw material liquid nitrogen tank is connected to the main heat exchanger, the main heat exchanger is connected to the raw material nitrogen inlet at the bottom of the distillation tower, the low-purity liquid nitrogen outlet at the bottom of the distillation tower is connected to the subcooler, the subcooler is connected to the main condenser evaporator, a throttle valve is provided on the connecting pipeline between the subcooler and the main condenser evaporator, the low-purity nitrogen outlet of the main condenser evaporator is connected to the subcooler, the subcooler is connected to the main heat exchanger, the main heat exchanger is connected to the nitrogen compressor, the nitrogen compressor is connected to the aftercooler, the aftercooler is connected to the main heat exchanger, the main heat exchanger is connected to the low-purity liquid nitrogen tank, the low-purity liquid nitrogen tank is connected to the connecting pipeline between the subcooler and the main condenser evaporator, and the connection is between the subcooler and the throttle valve;

[0008] The high-purity nitrogen outlet at the top of the distillation tower is connected to the main condenser evaporator, and the high-purity liquid nitrogen outlet of the main condenser evaporator is connected to the top of the distillation tower and the high-purity liquid nitrogen tank respectively.

[0009] Beneficial effects of the utility model:

[0010] 1. The utility model adopts a single-tower single-condensation distillation purification process to obtain a high-purity nitrogen product with a purity of ≤3ppmAr, which meets the requirements of the new chip production process (requiring the Ar content of the nitrogen product to be controlled below 3ppm), has a simple process flow, a high extraction rate, and is easy to operate.

[0011] 2. The process adopted by the utility model has no expansion refrigeration system, and provides cooling for the device by supplementing the liquid nitrogen source (low-purity liquid nitrogen tank); the cooling capacity of the liquid nitrogen source comes from the cooling capacity of the recovered raw liquid nitrogen, avoiding the conventional waste of cooling capacity caused by directly vaporizing the raw liquid nitrogen with an air bath vaporizer. By recycling the cooling capacity of the recovered raw liquid nitrogen, there is no need for expansion refrigeration of the expansion refrigeration system, which saves energy and reduces consumption.

[0012] 3. The process adopted by the utility model can produce low-purity liquid nitrogen products simultaneously while preparing the required high-purity liquid nitrogen products. The low-purity liquid nitrogen products mainly have high argon content and can be used as products for users who do not require high argon content. The entire production process can achieve no raw material loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the structure of the utility model. DETAILED DESCRIPTION

[0014] The following examples and drawings are used to further explain the present invention. The following examples are only used to illustrate the present invention, but are not used to limit the scope of implementation of the present invention.

[0015] A high-purity nitrogen preparation device for chip protection, such as Figure 1 As shown, it includes a raw material liquid nitrogen tank 1, a main heat exchanger 4, a distillation tower 7, a main condenser evaporator 8, a subcooler 9, a nitrogen compressor 5, an aftercooler 6, a low-purity liquid nitrogen tank 2 and a high-purity liquid nitrogen tank 3;

[0016] The raw material liquid nitrogen tank 1, the nitrogen compressor 5, the aftercooler 6, the low-purity liquid nitrogen tank 2 and the high-purity liquid nitrogen tank 3 are arranged outside the cold box, the main heat exchanger 4, the distillation tower 7, the main condenser evaporator 8 and the subcooler 9 are arranged inside the cold box, and the main condenser evaporator 8 is arranged above the distillation tower 7;

[0017] The raw material liquid nitrogen tank 1 is connected to the main heat exchanger 4, the main heat exchanger 4 is connected to the raw material nitrogen inlet at the bottom of the distillation tower 7, the low-purity liquid nitrogen outlet at the bottom of the distillation tower 7 is connected to the subcooler 9, the subcooler 9 is connected to the main condenser evaporator 8, and a throttle valve is provided on the connecting pipeline between the subcooler 9 and the main condenser evaporator 8, the low-purity nitrogen outlet of the main condenser evaporator 8 is connected to the subcooler 9, the subcooler 9 is connected to the main heat exchanger 4, the main heat exchanger 4 is connected to the nitrogen compressor 5, the nitrogen compressor 5 is connected to the aftercooler 6, the aftercooler 6 is connected to the main heat exchanger 4, the main heat exchanger 4 is connected to the low-purity liquid nitrogen tank 2, the low-purity liquid nitrogen tank 2 is connected to the subcooler 9 and the main condenser evaporator 8 on the connecting pipeline, and the connection is between the subcooler 9 and the throttle valve;

[0018] The high-purity nitrogen outlet at the top of the distillation tower 7 is connected to the main condenser evaporator 8, and the high-purity liquid nitrogen outlet of the main condenser evaporator 8 is connected to the top of the distillation tower 7 and the high-purity liquid nitrogen tank 3 respectively.

[0019] The functions of the above components are as follows:

[0020] Raw material liquid nitrogen tank 1, used for storing raw material liquid nitrogen;

[0021] A low-purity liquid nitrogen tank 2, used for storing low-purity liquid nitrogen;

[0022] High-purity liquid nitrogen tank 3, used for storing high-purity liquid nitrogen;

[0023] The main heat exchanger 4 is used for heat exchange between the pressurized raw liquid nitrogen, the low-purity nitrogen reheated by the subcooler 9 and the low-purity nitrogen cooled by the aftercooler 6. The pressurized raw liquid nitrogen is vaporized into raw nitrogen, the low-purity nitrogen reheated by the subcooler 9 is reheated to room temperature, and the low-purity nitrogen cooled by the aftercooler 6 is liquefied into low-purity liquid nitrogen;

[0024] Nitrogen compressor 5, used for pressurizing low-purity nitrogen after reheating to room temperature;

[0025] Aftercooler 6, used for cooling the low-purity nitrogen after pressurization;

[0026] A distillation tower 7, used for distilling and separating the raw nitrogen into low-purity liquid nitrogen and high-purity nitrogen;

[0027] The main condenser evaporator 8 is used for heat exchange between low-purity liquid nitrogen and high-purity nitrogen gas, where the low-purity liquid nitrogen is vaporized into low-purity nitrogen gas and the high-purity nitrogen gas is liquefied into high-purity liquid nitrogen;

[0028] The subcooler 9 is used for subcooling low-purity liquid nitrogen and reheating low-purity nitrogen gas.

[0029] The process of preparing high-purity nitrogen for chip protection using the device includes the following steps:

[0030] 1) The raw liquid nitrogen (purity of ≤3ppmO2, ≥1000ppmAr) in the raw liquid nitrogen tank 1 is pressurized to 0.25Mpa by the self-pressurizing vaporizer of the raw liquid nitrogen tank 1 and then introduced into the main heat exchanger 4 for heat exchange and vaporized into raw nitrogen gas. The raw nitrogen gas enters the distillation tower 7 from the raw nitrogen gas inlet at the bottom of the distillation tower 7;

[0031] 2) The raw nitrogen is separated into low-purity liquid nitrogen (purity ≥6ppmO2, ≥1800ppmAr) and high-purity nitrogen (purity ≤3ppmAr) after being rectified in the distillation tower 7;

[0032] 3) After the low-purity liquid nitrogen is supercooled by the cooler 9 and throttled by the throttle valve, it is introduced into the main condenser evaporator 8 as a cold source and vaporized into low-purity nitrogen (purity is ≥6ppmO2, ≥1800ppmAr). The low-purity nitrogen passes through the cooler 9 and the main heat exchanger 4 to be reheated to room temperature, and then exits the cold box and is introduced into the nitrogen compressor 5 to be pressurized to 0.7Mpa, and then cooled to about 40°C by the aftercooler 6 and enters the main heat exchanger 4 for heat exchange and is liquefied into low-purity liquid nitrogen. The low-purity liquid nitrogen is introduced into the low-purity liquid nitrogen tank 2. A part of the low-purity liquid nitrogen in the low-purity liquid nitrogen tank 2 is introduced into the main condenser evaporator 8 as a cold source after being throttled by the throttle valve, and the rest is used as a low-purity liquid nitrogen product (purity is ≥6ppmO2, ≥1800ppmAr);

[0033] High-purity nitrogen is introduced into the main condenser evaporator 8 as a heat source and liquefied into high-purity liquid nitrogen. A portion of the high-purity liquid nitrogen is introduced into the top of the distillation tower 7 as reflux liquid, and the rest is introduced into the high-purity liquid nitrogen tank 3 as a high-purity liquid nitrogen product (purity is ≤3ppmAr).

Claims

1. A high-purity nitrogen production device for chip protection, characterized in that: Including raw liquid nitrogen tank, main heat exchanger, distillation tower, main condenser evaporator, subcooler, nitrogen compressor, aftercooler, low-purity liquid nitrogen tank and high-purity liquid nitrogen tank; The raw material liquid nitrogen tank, nitrogen compressor, aftercooler, low-purity liquid nitrogen tank and high-purity liquid nitrogen tank are located outside the cold box, the main heat exchanger, distillation tower, main condenser evaporator and subcooler are located inside the cold box, and the main condenser evaporator is located above the distillation tower; The raw material liquid nitrogen tank is connected to the main heat exchanger, the main heat exchanger is connected to the raw material nitrogen inlet at the bottom of the distillation tower, the low-purity liquid nitrogen outlet at the bottom of the distillation tower is connected to the subcooler, the subcooler is connected to the main condenser evaporator, a throttle valve is provided on the connecting pipeline between the subcooler and the main condenser evaporator, the low-purity nitrogen outlet of the main condenser evaporator is connected to the subcooler, the subcooler is connected to the main heat exchanger, the main heat exchanger is connected to the nitrogen compressor, the nitrogen compressor is connected to the aftercooler, the aftercooler is connected to the main heat exchanger, the main heat exchanger is connected to the low-purity liquid nitrogen tank, the low-purity liquid nitrogen tank is connected to the connecting pipeline between the subcooler and the main condenser evaporator, and the connection is between the subcooler and the throttle valve; The high-purity nitrogen outlet at the top of the distillation tower is connected to the main condenser evaporator, and the high-purity liquid nitrogen outlet of the main condenser evaporator is connected to the top of the distillation tower and the high-purity liquid nitrogen tank respectively.

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