Waste hydrogen power generation device

Abstract

To provide a waste hydrogen power generation device that is capable of reusing hydrogen discarded at manufacturing facilities of semiconductors to generate power with less load of purification and assist in supplying electricity to facilities.SOLUTION: A waste hydrogen power generation device includes: a hydrogen generator such as an epitaxial growth device; a purification unit that collects waste hydrogen discarded from the hydrogen generator and removes impurities other than hydrogen by contact with water to prepare purified hydrogen; a storage unit that stores the purified hydrogen; and a power generation unit that operates a power generator by combusting the purified hydrogen supplied from the storage unit and oxygen in an atmosphere.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a waste hydrogen power generation device, and more particularly to a device that generates power by recovering hydrogen discharged in the semiconductor manufacturing process. [Background technology]

[0002] The manufacturing of semiconductors is made up of multiple steps that are complex and precisely controlled. Each step requires a large amount of electricity. Therefore, in semiconductor manufacturing facilities, effective use of energy and resources that were previously only released and not reused or utilized has been considered.

[0003] For example, power generation using exhaust heat generated during the operation of semiconductor manufacturing equipment has been proposed (see Patent Documents 1, 2, etc.). These proposed technologies have been effective in utilizing exhaust heat to a certain extent. However, it has been found that in the semiconductor manufacturing process, for example in epitaxial growth equipment, gas components such as hydrogen are generated from the gas introduced for epitaxial growth in addition to the exhaust heat.

[0004] Currently, hydrogen is highly flammable, so it is diluted to a safe concentration and released outside the manufacturing facility building (into the atmosphere) and then disposed of as is. Therefore, as a more effective use of hydrogen, it has been proposed to use the discarded hydrogen as fuel for fuel cells. However, in the case of fuel cells, extremely high purity hydrogen must be used. For example, epitaxial growth equipment contains components other than hydrogen. Therefore, it is not easy to remove impurities and increase the purity of hydrogen, and instead, there is the problem of increased costs for hydrogen purification. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2020-150045 A [Patent Document 2] International Publication WO2013 / 047320 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made in consideration of the above-mentioned points, and provides a waste hydrogen power generation device that can reuse hydrogen discarded in semiconductor manufacturing facilities for power generation with reduced purification burden, thereby assisting in the power supply to the facility. [Means for solving the problem]

[0007] That is, the waste hydrogen power generation apparatus of the embodiment is characterized by comprising a hydrogen generation unit, a purification unit that recovers waste hydrogen discarded from the hydrogen generation unit and removes impurities other than hydrogen to prepare purified hydrogen, a storage unit that stores the purified hydrogen, and a power generation unit that combusts the purified hydrogen supplied from the storage unit with oxygen in the atmosphere to operate a generator.

[0008] Furthermore, in the waste hydrogen power generation system, the hydrogen generation section may be an epitaxial growth device.

[0009] Furthermore, in the purification section of the waste hydrogen power generation system, impurities may be removed from the waste hydrogen by contacting it with water.

[0010] Furthermore, in the waste hydrogen power generation system, the power generation section may include a gas turbine section that rotates by combusting purified hydrogen and oxygen in the air, and the generator may be driven by the torque generated in the gas turbine section.

[0011] Furthermore, in the waste hydrogen power generation system, the power generation section may include an internal combustion engine section that obtains torque by combusting purified hydrogen with oxygen in the atmosphere, and the generator may be driven by the torque generated in the internal combustion engine section.

[0012] Furthermore, a power storage unit that stores the electric power generated in the power generation unit of the waste hydrogen power generation system may be provided.

[0013] Furthermore, in a waste hydrogen power generation system, the purification section, the storage section, and the power generation section may be housed in a single housing. Effect of the Invention

[0014] The waste hydrogen power generation device of the present invention comprises a hydrogen generation unit, a purification unit that recovers waste hydrogen discarded from the hydrogen generation unit and removes impurities other than hydrogen to prepare purified hydrogen, a storage unit that stores the purified hydrogen, and a power generation unit that combusts the purified hydrogen supplied from the storage unit with oxygen in the atmosphere to operate a generator.Therefore, for example, hydrogen discarded in semiconductor manufacturing facilities can be reused for power generation with less purification burden, thereby assisting in the power supply to the facility and subsidizing power usage. [Brief description of the drawings]

[0015] [Figure 1] 1 is a schematic diagram showing the overall configuration of a waste hydrogen power generation system according to a first embodiment. [Diagram 2] FIG. 2 is a first schematic diagram showing the configuration of a power generation section. [Diagram 3] FIG. 2 is a second schematic diagram showing the configuration of the power generation section. [Figure 4] FIG. 4 is a schematic diagram showing the overall configuration of a waste hydrogen power generation system according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The waste hydrogen power generation apparatus of the embodiment is an apparatus that recovers hydrogen that is discarded (discharged) mainly from epitaxial growth equipment in the semiconductor manufacturing process, and burns the hydrogen to operate a generator. In particular, a fuel cell that uses discarded hydrogen as fuel is not used. Hydrogen used as fuel for fuel cells must be refined to a high purity of 99% or more, otherwise the fuel cell device will malfunction and its efficiency will decrease. Therefore, the burden on the equipment, time, etc. required to refine the discarded hydrogen will increase. For this reason, the waste hydrogen power generation apparatus of the embodiment applies a power generation device found in hydrocarbon fuels as a method of obtaining electricity other than from fuel cells.

[0017] 1 is a schematic diagram showing the overall configuration of a waste hydrogen power generation system 1A of the first embodiment. The waste hydrogen power generation system 1A is equipped with a hydrogen generation section 10, a purification section 20, a storage section 30, and a power generation section 40. It also has a power storage section 60. A waste hydrogen power generation system 1B described later is similarly equipped with a hydrogen generation section 10, a purification section 20, a storage section 30, a power generation section 40 (generator 41), and a power storage section 60.

[0018] Electricity users 65 such as the manufacturing facility, equipment lighting, pumps, etc. are connected to the power storage unit 60. Pressure gauges 71, 72, 73, a check valve 74, a flow control valve 75, and other flow meters (not shown) are provided at various points in the gas transport piping 70. This makes it possible to monitor the appropriate pressure and flow rate of the gas (waste hydrogen, purified hydrogen) being transported.

[0019] The waste hydrogen power generation apparatus 1A of the first embodiment and 1B of the second embodiment (see FIG. 4) use an epitaxial growth apparatus 11 as the hydrogen generation unit 10. The epitaxial growth apparatus 11 has a space (furnace chamber 12) of an appropriate shape such as a cylinder or a hemisphere, and is an apparatus (furnace) for generating crystals on the surface of one to a plurality of silicon wafers 14 placed on a susceptor 13 inside. Gas required for crystal growth is introduced from a raw gas tank 15 into the furnace chamber 12 through a gas inlet 16 of each epitaxial growth apparatus 11. Gas after a predetermined reaction is discharged outside the furnace chamber 12 through a gas outlet 17. The positions of the gas inlet 16 and the gas outlet 17 of the epitaxial growth apparatus 11 may be arranged other than those shown in the figure, and are appropriately designed according to the structure and manufacturing capacity of the furnace chamber 12 of the epitaxial growth apparatus 11. For convenience, three epitaxial growth apparatuses 11 are shown in the figure. Of course, the number of epitaxial growth apparatuses 11 may be one, ten, or more.

[0020] In general, typical types of gases supplied to the epitaxial growth apparatus 11 and their reactions are as follows: (Epitaxial growth film formation) SiCl4+2H2 → Si+4HCl SiH2Cl2 → Si+2HCl SiH4 → Si+3HCl SiHCl3+H2 → Si+3HCl

[0021] (Silicon oxide film formation) SiH4+2O2 → SiO22H2O SiH4+2H2O → SiO24H2 SiCl4+2NO+2H2→ SiO2+4HCl+N2 SiCl4+2CO2+2H2→ SiO2+4HCl+2CO SiH2Cl2+2N2O → SiO2+2HCl+2N2

[0022] (Silicon nitride film formation) 3SiH2Cl2+4NH3→ Si3N4+6HCl+2H2 3SiH4+4NH3 → Si3N4+12H2 (Polycrystalline silicon film formation) SiH4 → Si+2H2

[0023] As shown in the above reaction formula, hydrogen is generated depending on the type of raw material gas as a result of the reaction of the gas supplied to the epitaxial growth apparatus 11 in conjunction with the supply of hydrogen to the epitaxial growth apparatus 11. In the epitaxial growth apparatus 11, unreacted hydrogen and hydrogen generated by the reaction are recovered as waste hydrogen and reused as fuel for power generation.

[0024] However, as shown in the above reaction formula, components other than hydrogen are also generated by the reaction in the epitaxial growth apparatus. For this reason, a purification section 20 is provided downstream of the epitaxial growth apparatus 11. The purification section 20 is called a scrubber or the like, and recovers waste hydrogen discarded from the hydrogen generation section and removes impurities other than hydrogen to prepare purified hydrogen. A known adsorbent and water are stored in the purification section 20. Hydrogen is almost insoluble in water. In contrast, hydrogen chloride is soluble in water. Therefore, hydrogen chloride is reduced by contacting the gas discharged through the gas outlet 17 with the water stored in the purification section 20. A filter 21 may be further provided downstream of the purification section 20 to improve the accuracy of hydrogen purification. The filter 21 collects components other than hydrogen, such as nitrogen and hydrogen chloride.

[0025] In the refining process to obtain purified hydrogen in the refining section 20, waste hydrogen comes into contact with water, and the purified hydrogen contains moisture. Generally, hydrogen used as fuel for fuel cells is nearly 100% pure hydrogen. Therefore, devices and processes are required to further remove moisture after refining. In contrast, in the embodiment, purified hydrogen is combusted, so barriers due to purity issues such as the moisture content of hydrogen can be ignored. Therefore, the burden of equipment and processing to increase the purity of hydrogen is reduced.

[0026] The purified hydrogen purified by the purification section 20 is stored in the storage section 30. The storage section 30 is a gas tank for hydrogen. The purified hydrogen is stored in the storage section 30 in order to supply hydrogen to the power generation section 40 in a sufficient amount and with a sufficient pressure. In the waste hydrogen power generation apparatus 1A of the first embodiment, hydrogen discharged from multiple epitaxial growth apparatuses 11 is stored in a single storage section 30.

[0027] A power generation unit 40 is installed downstream of the storage unit 30, and generates electricity using the refined hydrogen as fuel. Mechanisms for combusting the refined hydrogen include the use of a gas turbine as shown in the schematic diagram of Fig. 2 and the use of an internal combustion engine as shown in the schematic diagram of Fig. 3. A well-known generator 41 is installed in the power generation unit 40. The specifications and number of generators will vary depending on the scale of the facility.

[0028] In the schematic diagram of Fig. 2, the power generation section 40 includes a gas turbine section 42 that burns purified hydrogen with oxygen in the atmosphere to generate torque. The torque generated in the gas turbine section 42 drives a generator 41 to generate power. In the figure, purified hydrogen as fuel is supplied to the gas turbine section 42. Furthermore, air is supplied to an auxiliary turbine section 43 and compressed by the auxiliary turbine section 43, and the compressed air is supplied to the gas turbine section 42. As a result, the oxygen concentration becomes higher than at normal pressure, the hydrogen combustion efficiency increases, and the rotation speed of the gas turbine section 42, i.e., the turbine shaft 44, increases. The turbine shaft 44 is connected to the generator 41, which generates electricity.

[0029] The gas turbine section 42 can be adapted to various sizes, from large to small. However, it is not suitable for successively changing from a low speed range to a high speed range. In this case, a predetermined amount of purified hydrogen is stored in the storage section 30 and can be supplied to the gas turbine section 42 at a predetermined pressure, so that the gas turbine section 42 can rotate at a relatively stable rotation speed. Therefore, a power generation form using the gas turbine section 42 is a good example for the manufacturing facilities of a large-scale semiconductor factory, which has a relatively large supply of purified hydrogen.

[0030] In the schematic diagram of FIG. 3, the power generation unit 40 includes an internal combustion engine unit 45 that rotates by combusting refined hydrogen and oxygen in the air. The internal combustion engine unit 45 has a structure common to known gasoline engines, diesel engines, etc., and is a reciprocating engine in which refined hydrogen is used as fuel instead of gasoline or diesel. The internal combustion engine unit 45 shown in the figure includes a piston 47 inserted into a cylinder 46. Refined hydrogen and air are supplied to a space partitioned by the cylinder 46 and the piston 47 of the internal combustion engine unit 45, and the piston 47 moves within the cylinder 46 by explosive combustion. A rod 48 is connected to the piston 47, and the rod 48 is connected to a crankshaft 49. The linear motion of the piston 47 is converted into the rotational motion of the crankshaft 49. The crankshaft 49 is connected to a generator 41, and electricity is generated from the generator 41 by the rotational force generated in the crankshaft 49. In addition to the reciprocating engine that uses refined hydrogen as fuel, a rotary engine is also applicable.

[0031] The internal combustion engine unit 45 can flexibly adjust the rotation speed of the crankshaft 49 when the supply amount of purified hydrogen fluctuates. Therefore, it is possible to flexibly respond to the supply and demand relationship of the amount of power generation. The internal combustion engine unit 45 is preferably applied mainly to a configuration in which a relatively small amount of purified hydrogen is used as fuel, as seen in 1B of a second embodiment (see FIG. 4) described later.

[0032] 2 and 3 is an example of a power generation device and engine that uses purified hydrogen as fuel, and the configuration of the power generation unit naturally includes device configurations other than those described and shown in the drawings. In addition, necessary configurations that are omitted from the description and drawings are also appropriately included.

[0033] The power storage unit 60 includes a secondary battery that stores the power generated by the power generation unit 40. Examples of such batteries include lead-acid batteries, NaS (sodium sulfur) batteries, and lithium-ion batteries. The amount and type of secondary batteries in the power storage unit 60 are selected according to the power generation capacity and the amount of power used. Since the power is direct current when stored and becomes alternating current in the power usage unit 65, the power storage unit 60 may be provided with an inverter or the like that converts direct current to alternating current. Once electricity is generated by the power generation unit 40 (generator 41), it is charged into the secondary battery in the power storage unit 60 and is discharged from the power storage unit 60. This allows stable supply via the power storage unit 60 to equipment in a semiconductor factory that includes the epitaxial growth apparatus 11.

[0034] FIG. 4 is a schematic diagram showing the overall configuration of a waste hydrogen power generation system 1B of the second embodiment. In the waste hydrogen power generation system 1B, a power generation unit section 80 is provided corresponding to each of the multiple hydrogen generation sections 10. The power generation unit section 80 is configured with a single housing 81. The purification section 20, the storage section 30, and the power generation section 40 are stored in the housing 81 of the power generation unit section 80. In the figure, the power storage section 60 is also stored in the housing 81. In the waste hydrogen power generation system 1B of the second embodiment, components common to the waste hydrogen power generation system 1A of the first embodiment are described using the same symbols. In the power generation unit section 80, the piping connecting each section within the single housing 81 is appropriately equipped with a pressure gauge, a check valve, and a flow control valve.

[0035] As can be seen from the figure, one power generation unit 80 is assigned to one epitaxial growth apparatus 11 of one hydrogen generation section 10. Thus, power generation from each epitaxial growth apparatus 11 is possible. In the waste hydrogen power generation apparatus 1B, purified hydrogen discarded from one epitaxial growth apparatus 11 is not mixed with purified hydrogen from another epitaxial growth apparatus 11. For example, when an abnormality occurs in a certain epitaxial growth apparatus, instead of shutting down the entire hydrogen power generation apparatus, only the power generation unit connected to the problematic epitaxial growth apparatus can be shut down to minimize the drop in facility operating rate.

[0036] In addition, since the power generation unit section 80 itself has the ability to consistently treat waste hydrogen, there is no need to install tanks or the like separately, and the power generation unit section 80 itself can be relatively easily introduced and removed (carried in and out) within a semiconductor manufacturing factory or facility. Another advantage is that the burden of installing piping to transport and supply waste hydrogen and purified hydrogen is reduced. Furthermore, the number of power generation unit sections 80 can be adjusted to match the number of epitaxial growth devices 11 in operation in the hydrogen generation section 10, making it easy to introduce the system to suit the size of the semiconductor manufacturing factory.

[0037] The size of the power generation unit section 80 (its housing 81) is designed according to the size and capacity of the built-in purification section 20, storage section 30, power generation section 40, and further the power storage section 60. In addition, two epitaxial growth apparatuses 11 may be connected to one power generation unit section 80 (its housing 81).

[0038] As explained above, by using the waste hydrogen power generation system of the embodiment, hydrogen discarded in semiconductor manufacturing facilities can be reused for power generation with less purification burden, and the power supply to the facilities can be assisted. In particular, since hydrogen is used as fuel to be burned together with air, the purity of hydrogen required for fuel cells is not required, and the equipment and processing burden required for hydrogen purification is reduced.

[0039] Since the hydrogen generating section is an epitaxial growth device, it is possible to generate electricity from hydrogen discharged during the semiconductor manufacturing process, thereby assisting with power consumption.

[0040] Since impurities are removed from waste hydrogen by contacting it with water, the equipment and processing required to prepare purified hydrogen from waste hydrogen are simplified.

[0041] The power generation unit is equipped with a gas turbine section that rotates by combusting purified hydrogen with oxygen from the atmosphere. The generator is powered by the torque generated in the gas turbine section, making it possible to generate stable electricity even in large-scale facilities.

[0042] The power generation unit is equipped with an internal combustion engine that generates torque by combusting purified hydrogen with oxygen from the atmosphere. The generator is powered by the torque generated in the internal combustion engine, making it possible to generate electricity flexibly even in small-scale facilities.

[0043] Since the power storage unit is provided to store the power generated in the power storage unit, a stable supply of power to facilities, equipment, and the like is possible.

[0044] Because the purification unit, storage unit, and power generation unit are housed within a single casing, it can be easily installed and removed as a power generation unit within a manufacturing plant or facility, and the burden of installing piping for transporting and supplying waste hydrogen and purified hydrogen is reduced.

[0045] In addition, while the primary purpose of the hydrogen generation section will be the epitaxial growth device, the power generation unit section can also be introduced into factories where hydrogen is discharged from the manufacturing process, such as steel manufacturing facilities, thereby contributing to the effective use of waste hydrogen. [Explanation of symbols]

[0046] 1A, 1B Waste hydrogen power generation equipment 10 Hydrogen generation unit 11 Epitaxial growth equipment 12 Furnace room 13 Susceptor 14 Wafer 15 Raw gas tank 16 Gas inlet 17 Gas Outlet 20 Refining Department 21 Filters 30 Storage 40 Power Generation Division 41 Generator 42 Gas Turbine Section 44 Turbine shaft 45 Internal Combustion Engine Section 49 Crankshaft 60 Power storage unit 65 Power usage section 70 Piping 71, 72, 73 Pressure gauge 74 Check valve 75 Flow Control Valve 80 Power Generation Unit Section 81 Case

Claims

1. A hydrogen generating unit; a purification unit that recovers waste hydrogen discarded from the hydrogen generation unit and removes impurities other than hydrogen to prepare purified hydrogen; A storage unit that stores purified hydrogen; a power generation unit that burns the purified hydrogen supplied from the storage unit with oxygen in the atmosphere to operate a generator. A waste hydrogen power generation device.

2. 2. The waste hydrogen power generation system according to claim 1, wherein the hydrogen generation section is an epitaxial growth device.

3. 2. The waste hydrogen power generation apparatus according to claim 1, wherein impurities are removed from the waste hydrogen by contacting it with water in the purification section.

4. 2. The waste hydrogen power generation system according to claim 1, wherein the power generation section includes a gas turbine section that rotates by combusting purified hydrogen and oxygen in the atmosphere, and the generator is driven by the torque generated in the gas turbine section.

5. 2. The waste hydrogen power generation apparatus according to claim 1, wherein the power generation unit includes an internal combustion engine unit that obtains rotational force by combusting purified hydrogen with oxygen in the atmosphere, and the generator is driven by the rotational force generated in the internal combustion engine unit.

6. The waste hydrogen power generation system according to claim 1 , further comprising a power storage unit that stores the electric power generated in the power generation unit.

7. The waste hydrogen power generation system according to claim 1 , wherein the purification section, the storage section, and the power generation section are housed in a single housing.

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