KR20130099101A - Fluorine gas plant with seismic protection - Google Patents

Abstract

Disclosed is a fluorine gas plant comprising a fluorine generating unit 1 connected to a fluorine supply system 2 having a fluorine gas usage point 3, and a fluorine storage unit 4 connectable to the supply system, and having a seismograph. . Preferably the seismograph is an accelerometer and detects an earthquake. Seismographs generate signals that can cause interruptions of predetermined processes that are being carried out at the factory.

Description

Fluorine gas plant with earthquake protection {FLUORINE GAS PLANT WITH SEISMIC PROTECTION}

Claiming the priority of European Patent Application No. 10177216.8, filed on September 16, 2010, the invention, which is hereby incorporated by reference in its entirety, provides for protection against damage that may be caused by an earthquake. Fluorine gas plant.

Fluorine gases such as molecular fluorine (F ₂ ) and mixtures thereof are useful, for example, as cleaning gases for process chambers in semiconductor manufacturing or as etching gases for the manufacture of semiconductors, photovoltaic devices or flat panel displays.

Patent document WO 2006 / 067364-A1 discloses a method of delivering high purity fluorine to a processing system by supplying high purity fluorine to a fixed storage unit using an on-site fluorine generator and supplying high purity fluorine from the storage unit to the processing system. have.

Frequently on-site fluorine production plants ("F ₂ gas plants") are used for HF storage tanks, electrolytic cells that produce raw F ₂ gas and H ₂ as by-products, means for purifying raw F ₂ gas to obtain pure F ₂ , F Means including a buffer tank to deliver ₂ to the point of use, a scrubber to reduce F ₂ and HF in the gas blown from ambient air in an F ₂ gas plant, a scrubber to reduce F ₂ that is considered out of standard , An emergency scrubber to reduce F ₂ and HF in case of leakage, a scrubber to remove HF from H _2, which is also formed as a product, the electrolytic cell is heated before the electrolysis reaction is started, and the cell is And a thermo-regulated water-based circuit to cool the raw material F ₂ gas exiting the cell. HF is stored in an HF tank, which, when pressurized, delivers the HF to the cell through an open valve. The valve is opened when the F ₂ generator produces F ₂ . The vaporizer provides heat to HF, allowing HF to be introduced into the cell in vaporized form. The prepared F ₂ is purified by passing it through a heated NaF adsorption tower. Usually, the plant comprises means for analyzing the raw F ₂ gas and the purified F ₂ gas, such as FT-IR and UV spectrometers; An electric rectifier for supplying current to the electrolytic cell; Transformers; Public facilities and amenities such as laboratories, control board rooms that can control processing data from one or more control boards, and personal lounges; And emergency power sources (eg, diesel generators) if desired. The manufactured F ₂ is pressurized before delivery to the customer.

Gases containing elemental forms F ₂ , HF, and F ₂ or HF are, of course, potentially harmful compounds. Therefore, the F ₂ gas plant takes precautions to avoid hazards. Distribute emergency push buttons in the plant to ventilate the housing well, pass waste gas through the scrubber, deploy gas detectors to the plant, deposit smoke detectors and fire fighting facilities, and manually shut down if necessary. Lots of spare parts, such as pumps and scrubbers, are needed to get the plant up and running.

There is still a need for improvement regarding the safe operation of the fluorine gas plant. The present invention provides an improved fluorine gas plant and an improved method for producing pure F ₂ in a safer manner.

The fluorine gas plant according to the invention comprises an F ₂ generation unit 1 connected to a fluorine gas supply system 2 having a fluorine gas use 3, and a fluorine gas storage unit 4 connectable to the supply system. The fluorine gas plant includes at least one seismograph 15. See the accompanying FIG. 1 for these reference numbers. If desired, the parts of the plant can be assembled in the form of skids.

1 shows a fluorine gas plant according to the invention. The plant comprises a fluorine storage unit 4 with a number of storage containers 5 for F ₂ delivered to the point of use 3. The seismograph 15 is attached to the fluorine storage unit 5.

Seismographs must be resistant to aggressive media and preferably comprise individual housings. Seismographs can be bolted to the ground or to parts of a fluorine gas plant, for example. Preferably, two or more seismographs are prepared for multiplicity.

Preferably the plant comprises a shutdown system. The shutdown system stops the predetermined processes.

When an earthquake is detected, the seismograph generates a signal. The signal is one or more signals selected from the group consisting of optical signals, acoustic signals and electrical signals transmitted to a receiving side, for example a receiving side integrated in a control board. Preferably, the seismograph generates an electrical signal, which is sent to each unit in the plant for shutdown, or a control board that activates an automatic shutdown switch that stops at least one of the processes being performed at the fluorine gas plant. Is sent to. Configure the control board so that different processes can be assigned to a single shutdown switch or each process can be assigned to an individual shutdown switch.

Preferably, the signal from the seismograph is sent to the control board, which then automatically activates the shutdown switch (s). The present invention will now be described in conjunction with alternatives in which one shutdown switch interrupts several processes in progress. Shutdown switches stop predetermined processes performed in the plant, such as electrolysis processes, fluorine delivery to the point of use, or even all processes performed during F ₂ manufacture, including scrubbing, purification and analysis.

The connection between the seismograph and the automatic shutdown switch can be in the form of a cable, through which digital or analog signals can be transmitted. Alternatively, the seismograph and the shutdown switch may be connected via electromagnetic waves transmitted by the transmitter from the seismograph and received at the receiving end. The seismograph is preferably connected to a control board containing a shutdown system.

Seismograph detects seismic activity, especially earthquakes. When an earthquake is detected, the seismograph sends an electrical signal to an automatic shutdown switch (or switches), preferably included in the control board. The shutdown switch automatically shuts down pre-set processes in the fluorine gas plant. Preferably, the switch stops the current flowing through the rectifier to the electrolytic cell, thereby stopping the F ₂ generation process. The seismograph signal preferably initiates an optical signal such as a warning signal, for example an acoustic signal (such as a particular sound or announcement) or a warning lamp. The seismograph can also send a signal to the facility using the manufactured fluorine gas, indicating that the F ₂ transmission will be interrupted. It is to be understood that "fluorine gas" specifically refers to molecular fluorine (F ₂ ) and mixtures thereof, especially mixtures with inert gases. The inert gas can for example be selected from N ₂ O, oxygen, argon and nitrogen. Preferred fluorine gas consists of or consists essentially of F ₂ .

Seismographs can also trigger other measures. For example, by closing the valve of a storage tank storing HF, fluorine gas or F ₂ , no further gas is distributed through the lines and pipes, or the temperature of the electrolyte salt in the electrolytic cell is in the range of about 80 to 100 ° C. The electric heating portion applied to heat the retaining water or coolant can be switched off. By closing the valve to shut off the line or pipe, air or moisture can be prevented from entering. The scrubber can increase the capacity of the fans to ventilate the factory air. Inert gas can be blown to certain parts of the fluorine gas plant. Gases or liquids in these pipes or lines can be forced through scrubbers or emergency scrubbers, for example by passing N ₂ through these scrubbers. These measures can also help to prevent air or moisture from entering the line or pipe, which provides better conditions when the plant is restarted later. As a precaution, the diesel generator can be started to protect the power supply.

Preferably, the seismograph is an accelerometer.

The advantage of using seismographs, especially accelerometers, is that they are much more sensitive than humans in detecting that an earthquake is developing. Because of the early detection of earthquakes, it is possible to shut down a plant in a safe or at least less hasty manner, and allow workers in the plant to take additional safety precautions (including those to protect themselves). have.

Most seismometers suitable for application to F ₂ gas plants are known. Accelerometers are particularly suitable as seismometers because they can measure seismic action very well. Accelerometers of very different operating principles are known. For example, accelerometers are known that are based on the principle of resistivity (potential difference or extensiometric), inductance, electromagnetic, electrostatics, piezo resistance, piezoelectric or optoelectronic according to the Doppler principle. These accelerometers range from 10 ^-2 ms ^-2 (some even start at 10 ^-9 msec ^-2 ) to 10 ² msec ^-2 (some even up to 10 ⁶ msec ^-2 ), with 0 (excluding 0) Sense frequencies up to 10 ² Hz (some even up to 10 ⁴ Hz).

Specific devices that can be applied to the F ₂ gas plant of the present invention are as described in US Pat. No. 5,742,235. In such a device, a mass is suspended at the end of a leaf spring mounted on a base fixed to a member of the structure in contact with the ground or to an object inside the structure. The movement of the mass is separated from the movement of the base. When the base experiences an upward acceleration and displacement characteristic of the initial shock wave of the major earthquake, the mass inertia exerts a relative downward force on the spring, closing the electrical contact that causes current to flow through the light from the battery. . By adjusting the inertial mass, the damping force of the spring and the assembly, and the distance between the contacts, the spectral response of the assembly can be easily adjusted to any desired acceleration and displacement threshold.

The present invention will now be described in terms of one preferred embodiment for storing F ₂ -containing fluorine gas in a plurality of hollow bodies. According to one preferred embodiment, the fluorine gas plant comprises F ₂ stored to provide a backup for the fluorine generator. If the fluorine gas plant comprises an F ₂ generating unit 1 connected to a fluorine gas supply system 2 having a fluorine gas use 3, and a permanent fluorine gas storage unit 4 connectable to the fluorine supply system, If the fluorine gas storage unit comprises a plurality of hollow bodies 5, it is particularly possible to stably and economically supply fluorine demand to the point of use, while minimizing the safety risks associated with the presence of F ₂ .

It is to be understood that "permanent fluorine gas storage unit" specifically refers to a fluorine gas storage unit integrated in a fluorine plant. Preferably, the permanent fluorine gas storage unit stores more than 90%, more preferably more than 95%, most preferably about 100% by weight of fluorine gas based on the total weight of fluorine gas stored in the plant. It is designed to. Preferably, F ₂ is stored in gaseous form.

The "fluorine gas supply system" is specifically understood to represent a member capable of storing fluorine gas and capable of delivering fluorine gas from the F ₂ generating unit to the point of use. Possible components of the fluorine gas supply system include, but are not limited to, a supply line, a compressor, a mixer, and a buffer tank.

“Connectable” is specifically understood to indicate that the permanent fluorine gas storage unit is provided to be connected to one component of the fluorine gas supply system. Equipment suitable for connecting the fluorine storage unit to one component of the fluorine gas supply system comprises a manifold 6 connected via a line to each hollow body 5 of the fluorine gas storage unit, preferably each line The provision of a shut-off valve 7 in the opening makes it possible to isolate each hollow body individually. The manifold is also connected to one component of the fluorine gas supply system.

The fluorine gas storage unit preferably comprises 4 to 25 hollow bodies, more preferably 5 to 8 hollow bodies. Preferably these hollow bodies have substantially the same shape and dimensions. Cylindrical hollow bodies are preferred. Each hollow body preferably contains up to about 6 to 10 kg, preferably about 8 kg of F ₂ .

In a preferred embodiment of the fluorine gas plant according to the invention, the fluorine gas storage unit is contained in the enclosed space 8. The enclosed space is generally equipped with a fluorine detector which can trigger the connection of the enclosed space to the fluorine decomposition system 9. Suitably the confined space is connected to the fluorine decomposition system via a suction line 10, where the suction line is connected to a pump 11 operable to pump gas from the confined space to the fluorine decomposition system.

In another embodiment, the fluorine gas plant according to the invention further comprises a mixer 12, preferably a stationary mixer, which mixer is preferably capable of receiving fluorine from the fluorine generating unit 1 and inert gas. It is possible to receive an inert gas, preferably argon and / or nitrogen, from the feed line 13.

The invention also relates to a fluorine gas supply method comprising using the fluorine gas plant according to the invention to supply fluorine gas to a place of use.

1 shows an example of a preferred fluorine plant of the present invention.

The F ₂ generation unit 1 is connected to a fluorine gas supply system 2 that includes a fluorine gas supply line connected to a point of use 3, where the point of use is connected to a semiconductor manufacturing plant. According to an optional embodiment indicated by dashed lines, the fluorine gas supply line is connected to the mixer 12 which is also connected to the inert gas supply line 13, and another fluorine gas supply line is connected to the mixer 12 via the valve 14. To the destination (3). The fluorine gas supply system 2 is via a manifold 6 connected to each hollow body 5 of the fluorine gas storage unit 4, preferably via a line with a shut-off valve 7. It is also connected to the fluorine gas storage unit. The fluorine gas supply unit is housed in an enclosed space 8, which typically contains a fluorine detector that can cause the consolidation of the enclosed space to the fluorine decomposition system 9. The enclosed space is connected to the fluorine decomposition system via suction line 10, where the suction line is connected to a pump 11 operable to pump gas from the enclosed space to the fluorine decomposition system. A seismograph (accelerometer) 15 is located in the housing of the storage unit 8. Seismographs may be located anywhere in the plant or even close to the plant. When the seismograph detects the vibration caused by the earthquake and sends each signal to the control board, the control board automatically shuts off all the hollow bodies 5 in fluid contact with the lines and pipes providing fluorine gas to the user.

Preferably, the emergency scrubber is also left in a “stand by” state so that when harmful gases (HF or F ₂ ) are detected, the ambient atmosphere containing the hazardous gases is vented through an emergency scrubber for abatement. Can be. In general, the emergency scrubber can decompose fluorine gas, especially F ₂ , contained in one or two hollow bodies, and preferably decompose fluorine gas, especially F ₂ , contained in one hollow body. have.

Accordingly, the F ₂ back preferred realization of seismometer for receiving only the entire F portion of the _second back up the plant, respectively, and provided in a hollow body form by binding (e. G., An accelerometer), which improves the safety of the fluorine gas plant. Thanks to the seismograph, it is possible to respond quickly to an earthquake in development and to provide hollow bodies that store only a portion of the fluorine gas as compared to a tank that stores the total back-up fluorine gas volume. This is especially the case when there are emergency scrubbers with the ability to reduce F ₂ exiting at least one hollow body.

The invention also includes a fluorine generating unit 1 connected to a fluorine supply system 2 having a fluorine gas source 3, and a fluorine gas storage unit 4 connectable to the supply system, wherein at least one seismograph is provided. Provided is a method for producing a fluorine gas in a fluorine gas factory, the method passes the current through the molten KF / HF composition to be electrolyzed to form F ₂ and H ₂ , and selectively generated inert raw material F ₂ After mixing with the gas, it is purified and delivered to the point of use and / or fluorine gas storage unit. When the seismograph detects vibrations originating from the earthquake, the seismograph generates a signal that stops one or more processes being performed at the fluorine gas plant.

Preferably, the electrolysis process is stopped.

Preferably, the process of delivering fluorine gas to the point of use is also stopped.

Preferably, the signal closes the valve, shutting off the fluorine gas storage unit 4.

Preferably, the generated signal is sent to the control board, which causes the control board to start the process or interrupt the processes.

The fluorine gas plant according to the invention and the method according to the invention make it possible to supply a stable, economical and particularly safe fluorine gas supply even in the region where an earthquake has occurred. In particular, seismographs, fluorine gas storage systems and selective fluorine decomposition systems are very efficient, thus increasing plant safety.

Wherever the disclosure of all patents, patent applications, and publications incorporated herein by reference is inconsistent with the present disclosure, the present disclosure shall prevail.

Example

The fluorine plant according to the basic design of FIG. 1 (without mixer and inert gas supply) comprises a seismograph. In the factory, F ₂ generation unit (1) to produce an F ₂ of about 415kg / day via the HF electrolysis of molten KF · 2HF electrolyte. F ₂ is delivered to the point of use 3 through the fluorine gas supply system 2 and supplied to a flat panel display manufacturing plant using F ₂ for chamber cleaning. F ₂ is supplied to the customer as required.

The fluorine pressure in the fluorine supply system 2 and the F ₂ storage unit 4 is maintained at 3.5 barg (about 55 psig) by adjusting the F ₂ production in the F ₂ generation unit. The F ₂ storage unit 4 comprises six identical cylindrical containers each having an internal volume of 1.3 m ³ . The pressure control loop 14 is used to lower the fluorine pressure at the point of use 3 to 1.5 barg (about 24 psig).

In normal operation, the shut-off valve 7 is open, and the pressure difference between the F ₂ storage unit 4 and the point of use 3 is dependent on the various consumption patterns at the point of use 3 or the F ₂ generating unit. Even in the case where the manufacturing process of is stopped, a buffer for smoothly controlling the delivered fluorine gas flow is provided.

When an acceleration (or a strong explosion near the plant) that is characteristic of an earthquake is detected by the seismograph 15, the seismograph sends a signal, which may be in analog or digital form, to the control board in the plant. The control board then cuts off the current to the electrolytic cell and cuts off the supply of fluorine from the unit to the supply system 2. The control board also cuts off all supply of F _{2 that} has been stored in the F ₂ storage unit 4. In addition, pressurization of the HF supply tank, HF vaporization, HF supply valves to the electrolytic cell, heaters for the NaF adsorption tower, and valves delivering the F ₂ or F ₂ / inert gas mixture to the customer are stopped.

All fluorine-containing gases from the confined spaces are pumped through the suction line 10 to a fluorine decomposition system 9, which is a scrubber containing an aqueous KOH / potassium thiosulfate or sodium thiosulfate mixture. The scrubber can handle 15 kg of F ₂ .

Claims (14)

A fluorine generating unit 1 connected to the fluorine supply system 2 having a fluorine gas use point 3, and a fluorine gas storage unit 4 connectable to the supply system,
Fluorine gas plant with at least one seismograph. The factory of claim 1 wherein the seismograph is an accelerometer. The plant of claim 1 or 2 comprising a shutdown system. The plant as claimed in claim 1, wherein the fluorine gas storage unit comprises a plurality of hollow bodies. 5. The plant of claim 4 wherein the fluorine gas storage unit comprises between five and eight hollow bodies. The factory according to any one of claims 1 to 5, wherein the seismograph is connected to the control board and transmits signals to the control board. The plant according to claim 1, further comprising an emergency scrubber capable of reducing the F ₂ content of at least one hollow body (5). The plant of claim 3, wherein the shutdown system is connected to a power source for the F ₂ generation unit. The plant according to claim 3, wherein the shutdown system is connected with a valve capable of shutting off the fluorine gas storage unit. A fluorine generating unit (1) connected to the fluorine supply system (2) having a fluorine gas use point (3), and a fluorine gas storage unit (4) connectable to the supply system, wherein the fluorine gas storage unit includes at least one F ₂ gas production method in a fluorine gas plant including a seismograph,
An electric current is passed through the molten KF / HF composition to be electrolyzed to form F ₂ and H ₂ , the resulting raw material F ₂ is purified, delivered to the point of use and / or fluorine gas storage unit, and the seismograph is oscillated from the earthquake The seismograph generates a signal to stop one or more processes being performed at the fluorine gas plant. The method of claim 10, wherein the electrolysis process is stopped. 12. The method of claim 10 or 11, wherein the process of delivering fluorine gas to the point of use is stopped. The method according to any one of claims 10 to 12, wherein the signal closes the valve to shut off the fluorine gas storage unit (4). The method according to any one of claims 10 to 13, wherein the generated signal is sent to a control board, in which the control board initiates the operation or interrupting the processes.

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