Hydrogen fluoride pre-purification tower

Abstract

The hydrogen fluoride pre-purification tower is characterized in that a flat cover is connected with a cylinder body through a flange, a lining layer is arranged in the cylinder body, and a lug type support is arranged outside the cylinder body; a connecting piece is arranged at the other end of the cylinder body; and a distribution plate is arranged in the cylinder body near the connecting piece. According to the utility model, the acid liquor is distributed for the first time by utilizing the distribution disc and then is distributed again through the grid, and the single distribution of other equipment is changed into double distribution, so that the bias flow condition is reduced, the acid liquor is uniformly distributed in the pre-purification tower, and the impurity removal capability is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of hydrogen fluoride production, and particularly relates to a hydrogen fluoride pre-purification tower. Background Art

[0002] Hydrogen fluoride is primarily used in cleaning and etching processes during semiconductor manufacturing. Therefore, its purity and cleanliness are crucial for the yield, electrical performance, and reliability of integrated circuits. For example, in the fabrication of very large-scale integrated circuits, the quality standards for electronic-grade hydrofluoric acid used must meet the SEMI-2-9 standard (European ULSI level), the international standard for semiconductor equipment and materials. This standard requires an impurity content of 10 parts per billion (ppb). However, after hydrogen fluoride is produced, it can be mixed with a significant amount of impurities, such as water, sulfate, arsenic, and iodine. These impurities affect the purity of the product and can sometimes even cause color distortion. Therefore, pre-purification of the hydrogen fluoride is necessary.

[0003] At present, the pre-purification of hydrogen fluoride generally adopts a pre-purification tower, which mainly relies on the reverse contact between the crude acid pumped from the crude acid tank and the gas from the hydrogen fluoride generating tower to reduce impurities such as moisture and sulfate in the hydrogen fluoride gas.

[0004] Chinese patent CN202063726U discloses a hydrogen fluoride gas pre-purification tower, including a cylinder, a tower section, a hydrogen fluoride gas inlet, a filler support plate, a manhole, fillers, a washing acid distributor, a washing acid lower acid pipe and a hydrogen fluoride gas outlet. The cylinder is lined with a carbon brick layer, which can withstand high hydrogen fluoride gas temperatures and avoid lining bulging, thereby reducing equipment maintenance costs, extending service life, and ensuring normal production.

[0005] Chinese patent CN208599425U discloses hydrogen fluoride gas pre-purification equipment, including a tower body, which is a closed hollow cylinder. The tower body includes several layers of tower sections arranged sequentially from top to bottom. A dilute acid distributor is also provided between the topmost tower section and the adjacent lower tower section. The dilute acid distributor includes a vertical pipe, a horizontal pipe, and a distribution plate. The upper end of the vertical pipe is connected to the liquid phase inlet at the top of the topmost tower section for feeding dilute sulfuric acid. The lower end of the vertical pipe is connected to the horizontal pipe. The horizontal pipe is arranged above the distribution plate along the diameter direction of the distribution plate. Both ends of the horizontal pipe are blind ends. A plurality of holes are provided at the bottom of the horizontal pipe. The distribution plate includes a flat plate. Lower acid tanks are formed between adjacent concentric partitions. A plurality of lower acid holes are provided at the bottom of the lower acid tanks. Unlike conventional distributors, the dilute acid distributor of the utility model is convenient for cleaning impurities inside the distributor. Adjacent lower acid tanks are isolated by concentric partitions, but the top is not closed, avoiding the problem of excessive pressure due to excessive dilute acid in closed types.

[0006] Common hydrogen fluoride pre-purification towers contain only a single dilute acid distributor, which results in a consistent bias flow of acid after entering the tower. This leads to uneven acid distribution within the tower, uneven tower temperatures, and suboptimal removal of impurities such as moisture, sulfate, arsenic, and iodine. Therefore, a pre-purification tower device is needed that can reduce bias flow and improve tower efficiency. Summary of the Invention

[0007] In response to the above technical problems, the utility model provides a hydrogen fluoride pre-purification tower, which uses a distribution plate to initially distribute the acid liquid and then redistributes it through a grid, changing the other equipment from single distribution to double distribution, reducing the bias flow, making the acid liquid evenly distributed in the pre-purification tower, and improving the impurity removal capacity.

[0008] In order to achieve the above purpose, the utility model provides a hydrogen fluoride pre-purification tower, wherein the flat cover is connected to the cylinder via a flange, a lining is provided inside the cylinder, and an ear-type support is provided outside; a connecting piece is provided at the other end of the cylinder; a distribution plate is provided in the cylinder near the connecting piece.

[0009] Preferably, the bottom of the cylinder is provided with an acid discharge port, the top is provided with a gas outlet, the side bottom is provided with a gas inlet, and the side top is provided with an acid liquid inlet.

[0010] Preferably, the interior of the cylinder is provided with a first packing grid, a packing top cover, and a second packing grid in sequence from bottom to top.

[0011] Further preferably, fillers are contained between the first filler grid and the filler top cover.

[0012] Further preferably, tower internals are provided at the lower portion of the second packing grid.

[0013] Further preferably, the top of the second packing grid contains structured packing.

[0014] The beneficial effects of this utility model are: the acid liquid is initially distributed through the distribution plate and then redistributed through the grid, changing the single distribution system of other equipment to a double distribution system, reducing bias flow, ensuring uniform distribution of the acid liquid within the pre-purification tower, and improving impurity removal capacity. This utility model has the advantages of simple structure and good purification effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of the overall structure of the present invention, in which 1 is a flat cover, 2 is a flange, 3 is a gas inlet, 4 is a cylinder, 5 is a liner, 6 is an ear-type support, 7 is a packing, 8 is a tower internal, 9 is a structured packing, 10 is a connecting piece, 11 is an acid discharge port, 12 is a first packing grid, 13 is a gas outlet, 14 is a packing top cover, 15 is a second packing grid, 16 is a distribution plate, and 17 is an acid inlet. DETAILED DESCRIPTION

[0016] The following further explains the technical solution of the present invention with reference to the accompanying drawings and specific embodiments. It is worth noting that the following embodiments are only preferred embodiments of the present invention and should not be construed as limiting the present invention. The scope of protection of the present invention shall be determined by the claims. Any modifications or substitutions made to the technical solution of the present invention by those skilled in the art without creative effort shall fall within the scope of protection of the present invention.

[0017] Example 1

[0018] like Figure 1 As shown, a hydrogen fluoride pre-purification tower has a flat cover 1 connected to a cylinder 4 via a flange 2, a lining 5 is provided inside the cylinder 4, and an ear-type support 6 is provided outside; a connector 10 is provided at the other end of the cylinder 4; a distribution plate 16 is provided in the cylinder 4 near the connector 10 to perform initial distribution on the acid liquid entering the cylinder 4 and reduce bias flow; preferably, the lining 5 is a steel-lined polytetrafluoroethylene material to avoid excessive iron content caused by the equipment body.

[0019] Preferably, the cylinder 4 is provided with an acid discharge port 11 at the bottom, a gas outlet 13 at the top, a gas inlet 3 at the side bottom, and an acid liquid inlet 17 at the side top; the hydrogen fluoride gas enters the pre-purification tower from the gas inlet 3 at the side bottom, and contacts with the acid liquid flowing in from the side top during the upward movement to remove impurities such as moisture and sulfate contained in the hydrogen fluoride gas. The purified hydrogen fluoride gas is discharged from the gas outlet 13 at the top, and the acid liquid is discharged from the acid discharge port 11 at the bottom, and enters the next process.

[0020] Preferably, the cylinder 4 is provided with a first packing grid 12, a packing top cover 14, and a second packing grid 15 from bottom to top, so as to divide the packing position and support the packing, and at the same time further distribute the acid solution, further reduce the bias flow, and enable the acid solution to contact the hydrogen fluoride gas evenly and efficiently, thereby improving the tower efficiency.

[0021] Further preferably, a filler 7 is contained between the first filler grid 12 and the filler top cover 14 .

[0022] Further preferably, a tower internal 8 is provided at the lower portion of the second filler grid 15 and is made of a steel-lined polytetrafluoroethylene material, so as to reduce the additional iron elements brought about by the corrosion of the tower internal 8 and avoid affecting the purity of hydrogen fluoride.

[0023] Further preferably, the top of the second packing grid 15 contains structured packing 9 .

Claims

1. A hydrogen fluoride pre-purification tower, characterized in that: The flat cover (1) is connected to the cylinder (4) via a flange (2). A lining (5) is provided inside the cylinder (4) and an ear-type support (6) is provided outside the cylinder (4). A connecting piece (10) is provided at the other end of the cylinder (4). A distribution plate (16) is provided inside the cylinder (4) near the connecting piece (10).

2. A hydrogen fluoride pre-purification tower according to claim 1, characterized in that: The cylinder (4) is provided with an acid discharge port (11) at the bottom, a gas outlet (13) at the top, a gas inlet (3) at the side bottom, and an acid liquid inlet (17) at the side top.

3. A hydrogen fluoride pre-purification tower according to claim 1, characterized in that: The cylinder (4) is provided with a first packing grid (12), a packing top cover (14), and a second packing grid (15) in sequence from bottom to top.

4. A hydrogen fluoride pre-purification tower according to claim 3, characterized in that: A filler (7) is contained between the first filler grid (12) and the filler top cover (14).

5. A hydrogen fluoride pre-purification tower according to claim 3, characterized in that: The lower portion of the second filler grid (15) is provided with a tower internal (8).

6. A hydrogen fluoride pre-purification tower according to claim 3, characterized in that: The top of the second packing grid (15) contains structured packing (9).

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