TWI772801B - High-purity sulfuric acid manufacturing apparatus and high-purity sulfuric acid - Google Patents

Abstract

The present invention provides a high-purity sulfuric acid manufacturing apparatus, including an absorption tower and a phased stripping structure. The absorption tower has solvent. Sulfur trioxide (SO₃) gas enters the absorption tower and is absorbed by the solvent to become to-be-stripped sulfuric acid. Impurities are removed from the to-be-stripped sulfuric acid through a phased stripping process in the phased stripping structure, to become high-purity sulfuric acid. The phased stripping structure includes a first stripping device and a second stripping device. First stripping temperature of the first stripping device is different from second stripping temperature of the second stripping device.

Description

High-purity sulfuric acid process equipment and high-purity sulfuric acid

The present invention relates to high-purity sulfuric acid process equipment and high-purity sulfuric acid.

Sulfuric acid is a binary inorganic strong acid. Sulfuric acid is known as a colorless or pale yellow transparent liquid. When describing sulfuric acid, "concentration" is used to indicate the ratio of solute to solvent, usually in mass percent concentration (%); and "purity" is used to indicate the amount of impurities. The lower the impurity content, the higher the purity. higher.

The so-called "industrial grade" ordinary-purity sulfuric acid, in which the impurity content of specific items of concern (mainly metal ions) is about one part per million (ppm), also known as "ppm grade" sulfuric acid.

The so-called "electronic grade" high-purity sulfuric acid, in which the impurity content of the specific item of interest is about one part per billion (ppb), also known as "ppb grade" sulfuric acid. Among the "electronic grade" high-purity sulfuric acid, there is also the so-called "semiconductor grade" ultra-high-purity sulfuric acid, in which the impurity content of a specific item of concern is about one part per trillion (ppt), also known as "ppt grade" "sulfuric acid.

However, the current traditional sulfuric acid production process is still unable to provide high-purity sulfuric acid with very low impurity content. Therefore, there is an urgent need to provide an improved high-purity sulfuric acid process equipment to eliminate or alleviate the above-mentioned problems.

Figure 1 shows a flow chart of a sulfuric acid process.

Sulfur (usually S ₈ ) is combusted in air to produce sulfur dioxide (SO ₂ ). SO ₂ is converted into sulfur trioxide (SO ₃ ) using vanadium pentoxide (V ₂ O ₅ ) as a catalyst. SO ₃ is absorbed by sulfuric acid (H ₂ SO ₄ ) to form oleum, which can be regenerated into SO ₃ , which is then absorbed by sulfuric _acid into high-concentration sulfuric acid. High concentration sulfuric acid is diluted with water to a specific concentration and then aerated with compressed dry air (CDA) to form the final product.

According to one aspect of the present invention, a high-purity sulfuric acid process equipment is proposed, which includes an absorption tower and a staged aeration structure. The absorption column has solvent (eg, circulating acid). The sulfur trioxide gas enters the absorption tower and is absorbed by the solvent to become sulfuric acid to be aerated. The sulfuric acid to be aerated is removed from impurities through the staged aeration process of the staged aeration structure to become high-purity sulfuric acid. The staged aeration structure includes a first aeration device and a second aeration device, and the first aeration temperature of the first aeration device is different from the second aeration temperature of the second aeration device.

The present invention can reduce the consumption of compressed drying air by setting the first aeration temperature of the first aeration device to be different from the second aeration temperature of the second aeration device through the design of the staged aeration structure. Specifically, under the premise of preparing sulfuric acid of the same purity, the high-purity sulfuric acid process equipment of the present invention uses a staged aeration structure, and the required amount of compressed drying air is not based on the staged aeration structure. Two-thirds or less of the compressed dry air required by the sulfuric acid process equipment, so it can effectively save resources.

Optionally or preferably, the first aeration device is connected in series between the absorption tower and the second aeration device.

Optionally or preferably, the first aeration temperature is higher than the second aeration temperature.

Optionally or preferably, the first compressed drying air flow rate of the first aeration device is different from the second compressed drying air flow rate of the second aeration device.

Optionally or preferably, the flow rate of the first compressed drying air is 1 to 5 times the flow rate of the second compressed drying air.

Optionally or preferably, the high-purity sulfuric acid process equipment of the present invention further includes a circulation structure, and the circulation structure includes a staged cooling structure disposed between the first aeration device and the absorption tower.

Optionally or preferably, the ultrapure water enters the absorption tower.

Optionally or preferably, the solvent is ultrapure water or sulfuric acid; impurities include sulfur dioxide.

According to another aspect of the present invention, a high-purity sulfuric acid is provided, which is prepared by the above-mentioned high-purity sulfuric acid process equipment.

Further, its concentration is 95% to 99%, and its purity is that the sulfur dioxide content is less than 0.5 ppm. Further, its purity is iron (Fe), calcium (Ca), aluminum (Al), chromium (Cr), nickel (Ni), manganese (Mn), molybdenum (Mo), magnesium (Mg), potassium (K) ), sodium (Na), or zinc (Zn), or its ion content is less than 10 ppt.

The accompanying drawings and detailed descriptions will hereinafter make other objects, advantages, and novel features of the present invention more apparent.

100: High-purity sulfuric acid process equipment

110: Absorption tower

120: The first aeration device

130: First cooling device

140: Second cooling device

150: Second aeration device

160: Purification device

200: High-purity sulfuric acid process equipment

210: Absorption tower

230: First cooling device

240: Second cooling device

250: Aeration device

Figure 1 shows a flow chart of a conventional sulfuric acid process.

FIG. 2 shows a schematic structural diagram of a high-purity sulfuric acid process equipment of a comparative example.

FIG. 3 and FIG. 4 are schematic diagrams showing the structure of high-purity sulfuric acid process equipment according to one embodiment and another embodiment of the present invention, respectively.

Various embodiments of the present invention are provided below. These embodiments are used to illustrate the technical content of the present invention, but not to limit the scope of the right of the present invention. A feature of one embodiment can be applied to other embodiments by suitable modification, substitution, combination, isolation.

It should be noted that, in this document, unless otherwise specified, having "a" element is not limited to having a single such element, but may include one or more such elements.

In addition, in this document, unless otherwise specified, ordinal numbers such as "first" and "second" are only used to distinguish multiple elements with the same name, and do not mean that there is a rank, hierarchy, or execution order among them , or process sequence. A "first" element and a "second" element may appear together in the same component or separately in different components. The presence of an element with a higher ordinal number does not necessarily imply the presence of another element with a lower ordinal number.

In addition, in this document, the so-called "upper", "lower", "left", "right", "front", "rear", or "between" and other terms are only used to describe the relationship between multiple elements. Relative position, and can be generalized to include translation, rotation, or mirroring.

Furthermore, herein, unless specifically stated otherwise, "an element is on another element" or the like does not necessarily mean that the element is in contact with the other element.

Furthermore, herein, unless otherwise specified, the connection of two elements may include direct connection or indirect connection. In an indirect connection, one or more other elements may be present between the two elements.

Further, herein, unless otherwise specified, a numerical value is meant to include the numerical value the range of ±10%, especially the range of ±5% of the value. Unless otherwise specified, a numerical range is composed of subranges defined by the lower endpoint, lower quartile, median, higher quartile, and higher endpoint .

Furthermore, unless otherwise specified in the abstract, specification, scope of claims, or drawings, an element is "suitable for" another element, a configuration, or an action that describes a feature of the element, does not imply the existence of the other element, the configuration, or the action.

(Comparative example)

FIG. 2 shows a schematic structural diagram of a sulfuric acid process equipment 200 of a comparative example.

An outlet of the absorption tower 210 is connected to an inlet of the first cooling device 230 . An outlet of the first cooling device 230 is connected to an inlet of the aeration device 250 . On the other hand, another outlet of the first cooling device 230 is connected to an inlet of the second cooling device 240 . An outlet of the second cooling device 240 is connected to an inlet of the absorption tower 210 .

The absorption tower 210 can input ultrapure water and sulfur trioxide (SO ₃ ) gas. Ultrapure water is mixed with SO3 gas to form sulfuric _acid . Sulfuric acid may include impurities, so the aeration process of the aeration device 250 is required to remove the impurities to become high-purity sulfuric acid.

It is worth noting that, in the comparative example, the compressed drying air flow rate of the aeration device 250 needs to be 3000 LPM or more. (LPM means liters per minute, the same applies hereinafter.)

(Example)

FIG. 3 shows a schematic structural diagram of a high-purity sulfuric acid process equipment 100 according to an embodiment of the present invention. FIG. 4 shows a schematic structural diagram of a high-purity sulfuric acid process equipment 100 according to another embodiment of the present invention.

The high-purity sulfuric acid process equipment 100 basically includes an absorption tower 110 and a staged aeration structure.

An outlet of the absorption tower 110 is connected to an inlet of the first aeration device 120 . An outlet of the first aeration device 120 is connected to an inlet of the second aeration device 150 . The first aeration device 120 and the second aeration device 150 constitute a staged aeration structure.

On the other hand, another outlet of the first aeration device 120 is connected to an inlet of the first cooling device 130 . The first aeration device 120 and the first cooling device 130 can be separated into two devices or integrated into a single device. An outlet of the first cooling device 130 is connected to an inlet of the second cooling device 140 . An outlet of the second cooling device 140 is connected to an inlet of the absorption tower 110 . The first cooling device 130 and the second cooling device 140 form a staged cooling structure. The absorption tower 110, the first aeration device 120, and the staged cooling structure constitute a circulation structure. The first cooling device 130 and the second cooling device 140 may have the same or different temperatures.

Since the first aeration device 120 has replaced the position of the first cooling device 230 of the comparative example in FIG. 2 and has the function of dividing the flow, in other embodiments, the high-purity sulfuric acid process equipment 100 may not adopt the staged cooling structure, but One of the first cooling device 130 and the second cooling device 140 is omitted, as shown in FIG. 4 , or the first cooling device 130 and the second cooling device 140 are integrated into a single device.

In operation, the absorption column 110 has solvent. The solvent can be ultrapure water or sulfuric acid (H ₂ SO ₄ ), preferably concentrated sulfuric acid, especially 90%-99%, more especially 96%. Sulfuric _acid can be formed by mixing ultrapure water with SO3 gas. The absorption tower 110 has a liquid input port for inputting ultrapure water. The absorption tower 110 also has a gas input port for inputting SO ₃ gas. The SO ₃ gas enters the absorption tower 110 and is absorbed by the solvent (ultra-pure water, sulfuric acid, or concentrated sulfuric acid) to become sulfuric acid to be aerated. The sulfuric acid to be aerated can be diluted with ultrapure water to a desired concentration of sulfuric acid, usually 98% sulfuric acid, but not limited to this, and then enter the aeration process. Sulfuric acid may include impurities such as sulfur dioxide (SO ₂ ), which must be removed through a staged aeration process in a staged aeration configuration to become high-purity sulfuric acid.

The source of the above-mentioned SO ₃ gas is not limited, and can be produced by burning sulfur (usually S ₈ ) in air to generate SO ₂ gas _; Vanadium pentoxide (V ₂ O ₅ ) is used as a catalyst to convert SO ₂ gas into SO ₃ gas. It is worth noting that only a part or a small part of SO ₂ gas may be converted into SO ₃ gas, so SO ₃ gas will enter the absorption tower 110 with SO ₂ gas, affecting the purity of sulfuric acid. In addition, SO ₃ gas can pass through a purification device 160 and then enter the absorption tower 110 from the gas input port.

Regarding the water quality requirements of ultrapure water, the representative standards are: the resistivity at 25°C is at least about 15Ω-cm, the electrolyte concentration is less than 25ppb, the particle content is less than 150/ ^cm3 and less than 0.2 microns, and the microbial content is less than 10/cm ³ , and the total organic carbon is less than 100 ppb, but not limited thereto.

The step-by-step aeration process uses the first compressed drying air of the first aeration device 120 to remove impurities in the sulfuric acid to be aerated to form sulfuric acid after the first aeration, and then uses the second compressed dry air of the second aeration device 150 to dry Air is used to remove the impurities of sulfuric acid after the first aeration to form high-purity sulfuric acid. The above (for example) 98% sulfuric acid may be further diluted to (for example) 96% sulfuric acid, but not limited thereto. The purity of high-purity sulfuric acid will be defined below. The first compressed dry air or the second compressed dry air can be nitrogen or clean air, which have been removed from moisture or other impurities and will not react with sulfuric acid.

In the present invention, the first aeration temperature of the first aeration device 120 is set to be different from the second aeration temperature of the second aeration device 150 . For example, the first aeration temperature may be higher than the second aeration temperature. For example, the first aeration temperature may be set to 70°C to 100°C, and the second aeration temperature may be set to 45°C to 75°C.

The first compressed drying air flow rate of the first aeration device 120 may be set to be different from the second compressed drying air flow rate of the second aeration device 150 . The flow rate of the first compressed drying air may be 1 to 5 times the flow rate of the second compressed drying air. The flow rate of the first compressed drying air can be between 500LPM and 1000LPM, and The flow rate of the second compressed drying air may be between 500LPM and 1000LPM. Therefore, the sum of the first compressed drying air flow and the second compressed drying air flow is between 1000 LPM and 2000 LPM, which is significantly smaller than the 3000 LPM of the comparative example, so the amount of compressed drying air can be reduced.

On the other hand, a part of sulfuric acid in the first aerator 120 is returned to the absorption tower 110 through the circulation structure, and is called "circulating acid" as a solvent for absorbing SO ₃ gas. At any suitable location in the path of the recycle configuration, ultrapure water may be introduced to dilute the portion of the sulfuric acid concentration to, for example, 96%, but not limited thereto.

Optionally, the high-purity sulfuric acid process equipment 100 further includes a thin-film distiller (not shown) to generate high-purity SO ₃ gas from the absorption tower 110 . The high-purity SO ₃ gas can be re-introduced into the absorption tower 110 to be absorbed by the solvent of the absorption tower 110, and the sulfuric acid can be further purified, thereby improving its purity. In other words, the high-purity SO ₃ gas has a higher purity than the SO ₃ gas input from the gas input port.

In addition, it is worth noting that in this embodiment, the process of the sulfuric acid to be aerated into high-purity sulfuric acid does not go through a cooling device, but only goes through a staged aeration structure.

After analysis, the metal or its ion concentration (that is, the impurity content) contained in the high-purity sulfuric acid prepared by the high-purity sulfuric acid process equipment 100 of the present invention is shown in Table 1 below.

To sum up, through the design of the staged aeration structure in the present invention, the first aeration temperature of the first aeration device is set to be different from the second aeration temperature of the second aeration device, which can reduce the amount of compressed drying air. dosage. Specifically, under the premise of preparing sulfuric acid of the same purity, the high-purity sulfuric acid process equipment of the present invention uses a staged aeration structure, and the required amount of compressed drying air is not based on the staged aeration structure. Two-thirds or less of the compressed dry air required by the sulfuric acid process equipment, so it can effectively save resources. In addition, the content of (SO ₂ ) is less than 0.5 ppm, and the content of other metal ions is less than 10 ppt, so high-purity sulfuric acid can be prepared.

Although this invention has been described in terms of several embodiments, it should be understood that many other possible modifications and changes can be made without departing from the spirit of the invention and the claimed scope of the invention.

100: High-purity sulfuric acid process equipment

110: Absorption tower

120: The first aeration device

130: First cooling device

150: Second aeration device

160: Purification device

Claims (8)

A high-purity sulfuric acid process equipment (100), comprising: an absorption tower (110), the absorption tower (110) having a solvent; sulfur trioxide (SO ₃ ) gas enters the absorption tower (110) and is absorbed by the solvent, It becomes sulfuric acid to be aerated; a staged aeration structure; the sulfuric acid to be aerated is removed from impurities through the staged aeration process of the staged aeration structure to become high-purity sulfuric acid; the staged aeration structure includes a first aeration an aeration device (120) and a second aeration device (150), the first aeration temperature of the first aeration device (120) is higher than the second aeration temperature of the second aeration device (150); and A circulation structure includes a staged cooling structure, which is provided between the first aeration device (120) and the absorption tower (110). The high-purity sulfuric acid process equipment (100) according to claim 1, wherein the first aeration device (120) is connected in series between the absorption tower (110) and the second aeration device (150). The high-purity sulfuric acid process equipment (100) according to claim 1, wherein the first compressed drying air flow rate of the first aeration device (120) is different from the second compressed drying of the second aeration device (150) air flow. The high-purity sulfuric acid process equipment (100) according to claim 3, wherein the flow rate of the first compressed drying air is greater than 1 time to less than 5 times the flow rate of the second compressed drying air. The high-purity sulfuric acid process equipment (100) according to claim 1, wherein ultrapure water enters the absorption tower (110). The high-purity sulfuric acid process equipment (100) according to claim 1, wherein the solvent is ultrapure water, sulfuric acid, or concentrated sulfuric acid; and the impurities include sulfur dioxide (SO ₂ ). A high-purity sulfuric acid prepared by the high-purity sulfuric acid process equipment (100) of claim 1, the concentration of which is 95% to 99%, and the purity is that the content of SO ₂ is less than 0.5 ppm. The high-purity sulfuric acid according to claim 7, whose purity is iron (Fe), calcium (Ca), aluminum (Al), chromium (Cr), nickel (Ni), manganese (Mn), molybdenum (Mo), magnesium (Mg), potassium (K), sodium (Na), or zinc (Zn), or the ion content thereof is less than 10 ppt.

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