TWI669149B - Exhaust gas recombination power generation system and radio frequency plasma recombination device - Google Patents

Abstract

An exhaust gas recombination power generation system and a radio frequency plasma recombination device, the exhaust gas recombination power generation system comprises a pre-purification device, a radio frequency plasma recombination device and a gas power generation device. The pre-purification device can filter out substances in the heat-treated exhaust gas that cannot be recombined to generate combustible gases. The RF plasma recombination device is a connected group connected to the pre-purification device, and can generate a plasma for recombining the purified exhaust gas, and can recombine the purified exhaust gas into a regenerative mixed gas having a combustible gas. The gas power generation device is connected to a radio frequency plasma recombination device, and can generate electricity by using a regenerative mixed gas as a fuel. Through the pre-purification device and the RF plasma recombination device, the heat treatment waste gas can be effectively recovered and processed into an energy gas design, which can greatly reduce the carbon emission, and is an innovative design that is quite energy-saving and environmentally friendly.

Description

Exhaust gas recombination power generation system and radio frequency plasma recombination device

The present invention relates to a gas power generation system, and more particularly to an exhaust gas regenerative power generation system that uses a heat treatment exhaust gas discharged from a metal heat treatment device to generate electricity.

Heat treatment is to heat steel or other metal materials in a solid state to a certain temperature and then to cool them. There are many metal heat treatment methods, usually quenching, annealing and tempering, mainly through heat treatment such as heating, cooling and bathing. The process changes the normal temperature structure of a metal or steel material to the physical and mechanical properties required for processing. The environmental conditions of the heat treatment are mainly controlled by the gas atmosphere and temperature in the heat treatment furnace. In order to stabilize the product, the formulated component gas must be continuously fed into the furnace during the heat treatment to stabilize the process atmosphere, so the gas dosage is extremely high and the cost is high. .

The gas composition of the exhaust gas discharged from the heat treatment furnace roughly comprises the following components: methane (CH ₄ ), nitrogen (N ₂ ), hydrogen (H ₂ ), propane (C ₃ H ₈ ), carbon monoxide (CO), carbon dioxide (CO ₂ ), Methanol (CH ₃ OH), and other hydrocarbons (C _n H _m ), although the exhaust gas from the heat treatment furnace is still flammable, due to consideration of the safety of the plant staff and environmental issues, there is still no proper recycling. The way of storage, so the current practice is to burn all the fire, therefore, invisible energy waste, and will produce more carbon dioxide emissions.

Accordingly, it is an object of the present invention to provide an exhaust gas recombination power generation system and a radio frequency plasma recombination apparatus which are capable of improving at least one of the disadvantages of the prior art.

Thus, the exhaust gas recombination power generation system of the present invention can generate electricity by heat treatment exhaust gas discharged from a metal heat treatment facility. The exhaust gas regenerative power generation system comprises a pre-cleaning device, a radio frequency plasma recombining device, and a gas generating device. The pre-purification device is configured to introduce the heat-treated exhaust gas discharged from the metal heat treatment device, and filter out the material in the heat-treated exhaust gas that cannot be recombined by plasma to generate a combustible gas to output a purified exhaust gas. The RF plasma recombining device is connected to the pre-purification device, and can generate a plasma for reprocessing the purified exhaust gas output from the pre-purification device, and can reconstitute the purified exhaust gas. A regenerative mixed gas having a combustible gas. The gas power generation device is connected to the radio frequency plasma recombination device, and can generate electricity by using the regenerative mixed gas as a fuel.

Therefore, the exhaust gas recombining device of the present invention is suitable for reconstituting the purified exhaust gas plasma into a regenerative mixed gas having a combustible gas, which is produced by filtering the tar and carbon particles after the heat treatment exhaust gas discharged from the metal heat treatment device. The radio frequency plasma recombining device comprises a cavity for introducing the purified exhaust gas to be subjected to plasma recombination, two parallel electrode plates arranged in parallel in the cavity, and one electrically connected to the parallel electrode plates. And driving the parallel electrode plates to generate a radio frequency plasma control module for reconstituting the purified exhaust gas into the plasma of the regenerative mixed gas, and a parallel electrode plate disposed between the parallel electrode plates and one of the parallel electrode plates Electrically connected to contact the conductive carbon cloth.

The utility model has the advantages that: through the design of the pre-purification device and the radio frequency plasma recombination device, the heat treatment waste gas discharged from the metal heat treatment equipment can be effectively recovered and processed into an energy gas, thereby greatly reducing carbon emissions, which is quite energy-saving and environmentally friendly. Innovative design.

Referring to FIG. 1 and FIG. 2, an embodiment of the exhaust gas recombination power generation system of the present invention is applicable to an exhaust gas discharge port connected to a metal heat treatment device, capable of guiding the heat treatment exhaust gas discharged after heat treatment of the metal heat treatment device, and The heat-treated exhaust gas is reorganized into a gas having a simple chemical structure and can be directly used by a gas generator. The metal heat treatment apparatus may be a heat treatment continuous furnace or a rotary quench furnace, etc., and is not limited to the above types. The composition of the heat treatment exhaust gas includes, but is not limited to, methane (CH ₄ ), nitrogen (N ₂ ), hydrogen (H ₂ ), propane (C ₃ H ₈ ), carbon monoxide (CO), carbon dioxide (CO ₂ ), methanol (CH _{3 )} OH), and other hydrocarbons (C _n H _m ).

The exhaust gas recombination power generation system comprises a pre-purification device 3 for assembling an exhaust gas discharge port of the metal heat treatment device, a radio frequency plasma recombining device 4 connected to the pre-purification device 3, and a group connected thereto. A post-purification device 5 of the radio frequency plasma recombination device 4, and a gas power generation device 6 connected to the post-purification device 5.

The pre-purification device 3 sucks the exhaust gas discharged from the metal heat treatment device into the interior thereof for pre-purification treatment, and can filter out the material in the heat-treated exhaust gas that cannot be recombined by plasma to generate combustible gas, and can filter The purified exhaust gas produced after the treatment is sent to the radio frequency plasma recombining device 4.

Due to the metal heat treatment process, the cutting oil or other processing oil remaining on the metal surface will generate tar, carbon particles and oil and gas under high temperature heating, and tar, carbon particles and oil and gas will be dispersed in the atmosphere. Therefore, the heat-treated exhaust gas discharged after the heat treatment may contain tar and carbon particles. However, the tar and the carbon particles cannot be burned, and the radio frequency plasma recombination device 4 is contaminated. Therefore, when the heat treatment waste gas discharged from the metal heat treatment device is recycled, the tar and the carbon particles must be filtered out to obtain the purified product. Exhaust gas.

In the present embodiment, the pre-purification device 3 is a filter composed of an oil collecting groove, a stainless steel ball and a PP non-woven fabric, and can adsorb and filter tar and carbon particles in the heat-treated exhaust gas. However, in practice, the composition of the pre-cleaning device 3 and the manner of filtering the tar and carbon particles are not limited thereto.

The radio frequency recombination device 4 includes a cavity 41 connected between the pre-purification device 3 and the post-purification device 5, and two parallel electrode plates 42 disposed in the cavity 41 in parallel. A conductive carbon cloth 44 disposed between the parallel electrode plates 42 and a radio frequency plasma control module 43 disposed outside the cavity 41 and electrically connected to the parallel electrode plates 42.

The cavity 41 defines a plasma reaction space for arranging the parallel electrode plates 42 and can be controlled to be opened to introduce the purified exhaust gas filtered by the pre-purification device 3 into the plasma reaction space, and The gas that has been recombined by the plasma in the plasma reaction space can be controlled to be turned on to the post-purification device 5.

The conductive carbon cloth 44 is electrically connected to the parallel electrode plate 42 disposed underneath, and the surface of the conductive carbon cloth 44 is modified with a metal catalyst, and the parallel electrode plate 42 in contact with the electrical connection cooperates to generate electricity. The electrode of the slurry can improve the plasma recombination conversion efficiency of the purified exhaust gas. In this embodiment, the selection criteria of the conductive carbon cloth 44 are: a basis weight of 300 g/m ² or more, a thickness of 0.5 mm or more, a length resistance of 5 Ω (30 cm X 30 cm) or less, and covering the electrical connection contact. The larger the proportion of the parallel electrode plates 42, the better, but the parallel electrode plates 42 are slightly exposed (within 10% of the exposed ratio) without affecting the recombination effect. In this embodiment, the conductive carbon cloth 44 completely covers the parallel electrode plate 42.

The metal catalyst is selected from the group consisting of noble metals, transition metals, and metal oxides such as, but not limited to, Pt, Zn, Al ₂ O ₃ , CuO, CeO ₂ . The metal catalyst modification method of the conductive carbon cloth 44 is to uniformly mix the carbon powder and the cyclohexanone in a weight ratio of 1:5:94 to form a metal mixed liquid. Then, the conductive carbon cloth 44 is immersed in the metal mixed liquid, and the surface of the conductive carbon cloth 44 is adhered to the metal mixed liquid, and then the conductive carbon cloth 44 is taken out and exposed to the atmosphere (1 atm, 25~). 50 ^o C, RH 50%) After 8 hours of drying, the metal catalyst modification of the conductive carbon cloth 44 is completed.

The radio frequency plasma control module 43 can generate plasma in the plasma reaction space via the parallel electrode plates 42. On the one hand, the slurry can be used to decompose the oil and gas in the purified exhaust gas, and on the other hand, the plasma will be utilized. The purified exhaust gas is recombined into a regenerative mixed gas containing a combustible gas component usable by the gas generator 62. Since the RF plasma control module 43 controls the parallel electrode plates 42 to generate plasma as a conventional technique and has many types, it will not be described in detail.

The post-purification device 5 can guide and filter the regenerative mixed gas discharged by the radio frequency recombination device 4, and can filter the gas in the regenerative mixed gas that cannot be used as the fuel for generating electricity of the gas generating device 6, and correspondingly output one Combustible after purification. The post-purification device 5 mainly filters out the gas which is not suitable for the gas generator 62, such as hydrogen sulfide and ammonia gas generated during the recombination reaction of the plasma, so as to be directly used for the gas power generation. The purified combustible gas of the device 6. In this embodiment, the post-purification device 5 is a water washing tower, and the hydrogen sulfide and/or ammonia gas in the regenerated mixed gas is filtered by a gas washing method. However, when implemented, the type of the post-purifying device 5 is not This is limited.

The gas power generating device 6 includes a gas storage tank 61 connected to the post-cleaning device 5, and a gas generator 62 connected to the gas storage tank 61. The gas storage tank 61 can pressurize and collect the purified combustible gas filtered and discharged by the post-purification device 5, and can be opened to inject the stored combustible combustible gas into the gas generator 62. The gas generator 62 is capable of combusting the purified combustible gas for power generation. Since the gas generator 62 is of a conventional technique and of many types, it will not be described in detail.

Hereinafter, a plurality of experimental examples are used to illustrate the hydrogen and methane recombination efficiency of the radio frequency plasma reconstituting device 4 in the case where the conductive carbon cloth 44 is modified with different metal catalysts, and the activated carbon cloth is used as a control group for comparison.

Experimental Example (1): Conductive carbon cloth 44 of unmodified metal catalyst and methane (CH ₄ ) conversion efficiency of activated carbon cloth during plasma recombination.

The equipment/material of the RF plasma recombination device 4 is shown in Table 1:

Activated carbon cloth specifications: The basis weight is 100 g/m ² or more, the thickness is 0.4 mm or more, the length resistance is 10 ⁶ Ω (30 cm X 30 cm) or less, and the specific surface area is 1000 m ² /g or more.

Using N ₂ as a carrier gas, with CH ₄ for plasma recombination reaction, the composition ratio of N ₂ /CH ₄ is 8/24 (total flow rate 32 sccm), the pressure value is 2.7×10 ^-1 Toor, and the radio frequency plasma is controlled. The RF (13.56 MHz) input power of the control module 43 is recombined for 30 min at 25 W, 50 W, 75 W, 100 W and 125 W. After the recombination reaction, the composition of the gas after the reaction was collected and analyzed.

Referring to Figures 3 and 4, after the plasma recombination reaction, the volume of hydrogen produced by the conductive carbon cloth 44 (V _H2 %) is significantly better than that of the non-conductive carbon cloth 44, and is superior to the activated carbon cloth. Conditions, and the recombination conversion efficiency of methane is also significantly higher than that of non-conductive carbon cloth 44 conditions and activated carbon cloth conditions. Obviously, conductive carbon cloth 44 helps to increase the hydrogen production amount and recombination conversion efficiency of plasma recombined methane.

Experimental Example (2): Plasma recombination of LPG (Liquefied Petroleum Gas) was carried out using a conductive carbon cloth 44 having a surface modified with a metal catalyst.

Electrochemical recombination of LPG with five kinds of metal catalyst modified conductive carbon cloth 44, RF (13.56 MHz) input power 150 W recombination reaction for 20 min, carrier gas is nitrogen (N ₂ ), the volume ratio of carrier gas to LPG is 3/27, total flow is 30 sccm. After the end of the reaction, the composition of the gas after the recombination reaction was collected and analyzed. The metal catalysts are zinc (Zn), aluminum oxide (Al ₂ O ₃ ), copper oxide (CuO), cerium oxide (CeO ₂ ), and platinum (Pt), respectively. The composition of the gas after the recombination reaction is shown in Table 2.

Referring to FIG. 5, under the condition of no conductive carbon cloth 44, the volume percentage of hydrogen (V _H2 %) is 46.4%, and the volume percentage of methane (V _CH4 %) is 11.0%, and the conductive carbon cloth without modified metal catalyst. V 44 is hydrogen yield was 51.3% _H2%, the volume percentage (V _CH4%) 11.5% methane. When the conductive carbon cloth 44 is modified with a metal catalyst, the hydrogen production and methane production after recombination are significantly increased, so the conductive carbon cloth 44 and the conductive carbon cloth 44 modified with the metal catalyst do contribute to the improvement of the LPG. Recombination conversion efficiency of propane.

Experimental Example (3): Recombination of heat treatment waste gas of metal heat treatment equipment.

When the metal heat treatment apparatus performs metal heat treatment, methanol and propane are used as a heat treatment atmosphere, and the volume ratio of methanol to propane is 1/4. Since the metal heat treatment equipment is an open system, a certain proportion of nitrogen gas is present in the atmosphere.

The heat-treated exhaust gas discharged from the metal heat treatment apparatus filters out tar and carbon particles through the pre-purification device 3 to obtain the purified exhaust gas. Then, the purified exhaust gas is injected into the radio frequency plasma recombination device 4 to carry out a recombination reaction to obtain the regenerated mixed gas. The radio frequency plasma recombination device 4 uses nitrogen as a carrier gas, and controls the total air intake amount to be 65 sccm, and performs plasma recombination experiments with 100 W radio frequency power. Before and after gas recombination, GC-TCD was used to analyze the gas composition before and after recombination, mainly to analyze H ₂ , N ₂ , CO, CO ₂ , CH ₄ , C ₂ H ₄ , C ₂ H ₆ , C. The composition ratio of ₃ H ₈ was observed for the composition ratio change of the above eight gases before and after recombination. The gas composition of the purified exhaust gas before recombination is shown in Table 3, and the composition of the regenerated mixed gas after the recombination reaction is shown in Table 4.

Referring to FIG. 6, after the purified exhaust gas is reorganized by the RF plasma recombination device 4, the proportion of hydrogen is obviously increased, the proportion of propane is significantly decreased, and methane, ethane and ethylene which are not present before recombination, and nitrogen, carbon monoxide and Carbon dioxide does not have a plasma recombination reaction, so the proportion before and after the plasma reaction is about the same. Hydrogen, methane, ethane and ethylene are all products of the propane cracking recombination reaction.

It can be confirmed that the RF plasma recombination device 4 of the present invention can effectively reconstitute the heat treatment exhaust gas discharged from the heat treatment apparatus into the regenerative mixed gas which is more suitable for the gas generator 62, so the exhaust gas recombination power generation system of the present invention It can be used for the recycling of heat treatment waste gas from metal heat treatment equipment.

In summary, through the pre-purification device 3, the radio frequency plasma recombination device 4 and the post-purification device 5, the heat treatment waste gas discharged from the metal heat treatment equipment after metal processing can be effectively converted into a chemical structure. It is simple and suitable for the combustible gas of the gas generator 62, and can be used for the gas generator 62 to be burned for power generation, so that the heat treatment exhaust gas discharged from the metal heat treatment equipment can be effectively recovered and processed into an energy gas, which can greatly reduce carbon emissions. Quantity is an innovative design that is quite energy efficient and environmentally friendly. Therefore, the object of the present invention can be achieved.

However, the above is only the embodiment of the present invention, and the scope of the invention is not limited thereto, and all the simple equivalent changes and modifications according to the scope of the patent application and the patent specification of the present invention are still Within the scope of the invention patent.

3‧‧‧Pre-cleaning device

4‧‧‧RF plasma recombination device

41‧‧‧ cavity

42‧‧‧Parallel electrode plates

43‧‧‧RF plasma control module

44‧‧‧ Conductive carbon cloth

5‧‧‧Post purification device

6‧‧‧ gas power generation unit

61‧‧‧ gas storage tank

62‧‧‧ gas generator

Other features and advantages of the present invention will be apparent from the embodiments of the present invention, wherein: FIG. 1 is a schematic diagram of a system architecture of an embodiment of the exhaust gas recombination power generation system of the present invention; FIG. 2 is a schematic diagram of the embodiment. FIG. 3 is a schematic cross-sectional view of the radio frequency plasma recombination apparatus; FIG. 3 is a graph showing the experimental example (1) of the embodiment, illustrating the volume change of hydrogen generated by methane recombination by radio frequency plasma; FIG. 4 is an experimental example of the embodiment (1) The graph of the plasma recombination conversion efficiency of methane; FIG. 5 is a histogram of the experimental example (2) of the embodiment, illustrating the volume change of hydrogen, methane and propane produced by the recombination of LPG after radio frequency plasma; And Fig. 6 is a histogram of the experimental example (3) of the embodiment, illustrating the volume change of various gases generated after the heat treatment exhaust gas is recombined by the radio frequency plasma.

Claims (10)

An exhaust gas recombination power generation system capable of generating electricity by heat treatment exhaust gas discharged from a metal heat treatment device, the exhaust gas regenerative power generation system comprising: a pre-purification device for introducing the heat treatment exhaust gas discharged from the metal heat treatment device, and filtering The heat-treated exhaust gas cannot be recombined by plasma to generate a combustible gas substance, and outputs a purified exhaust gas; a radio frequency plasma recombining device connected to the pre-purification device and capable of generating output for the pre-purification device The purified exhaust gas is subjected to plasma recombination treatment, and the purified exhaust gas can be recombined into a regenerative mixed gas having a combustible gas; and a gas generating device connected to the radio frequency plasma recombining device can be used for the regenerative mixing The gas generates electricity for the fuel. The exhaust gas recombination power generation system according to claim 1, further comprising a post-purification device connected between the radio frequency plasma recombination device and the gas power generation device, wherein the post-purification device can filter the regenerative gas mixture and cannot be used as The gas for generating fuel of the gas power generation device. The exhaust gas recombination power generation system according to claim 2, wherein the post-purification device filters hydrogen sulfide and/or ammonia gas in the regenerated mixed gas by gas washing. The exhaust gas recombination power generation system according to claim 1, 2 or 3, wherein the radio frequency plasma recombination device comprises a cavity for introducing the purified exhaust gas to be subjected to a gas recombination reaction, and two chambers are disposed in parallel a parallel electrode plate, a radio frequency plasma control module capable of driving the parallel electrode plates to reconstitute the purified exhaust gas into a plasma of the regenerative gas mixture, and a device disposed between the parallel electrode plates A conductive carbon cloth in electrical contact with one of the parallel electrode plates. The exhaust gas recombination power generation system according to claim 4, wherein the conductive carbon cloth is modified with a metal catalyst. The exhaust gas recombination power generation system according to claim 5, wherein the metal catalyst is selected from the group consisting of a noble metal, a transition metal, and a metal oxide. The exhaust gas recombination power generation system according to claim 4, wherein the conductive carbon cloth covers more than 90% of the area of the top surface of the parallel electrode plate below. The utility model relates to a radio frequency plasma recombining device, which is suitable for recombining a purified exhaust gas plasma into a regenerative mixed gas having a combustible gas, wherein the purified exhaust gas is generated after the heat treatment exhaust gas discharged from a metal heat treatment device is filtered by tar and carbon particles. The RF plasma recombining device comprises: a cavity for introducing the purified exhaust gas to be recombined with plasma; two parallel electrode plates disposed in parallel in the cavity; an RF plasma control module, Electrically connected to the parallel electrode plates, and capable of driving the parallel electrode plates to generate plasma for reconstituting the purified exhaust gas into the regenerated mixed gas; and a conductive carbon cloth disposed between the parallel electrode plates, And is in electrical contact with one of the parallel electrode plates. The radio frequency plasma recombining device of claim 8, wherein the conductive carbon cloth is modified with a metal catalyst. The radio frequency plasma recombination device of claim 9, wherein the metal catalyst is selected from the group consisting of noble metals, transition metals, and metal oxides.