CN115247974A - System and method for thermochemical heat storage by using methane combustion waste heat - Google Patents
System and method for thermochemical heat storage by using methane combustion waste heat Download PDFInfo
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- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 title claims abstract description 248
- 238000005338 heat storage Methods 0.000 title claims abstract description 128
- 238000002485 combustion reaction Methods 0.000 title claims abstract description 70
- 239000002918 waste heat Substances 0.000 title claims abstract description 60
- 238000000034 method Methods 0.000 title claims abstract description 40
- 238000009423 ventilation Methods 0.000 claims abstract description 75
- 239000007789 gas Substances 0.000 claims abstract description 67
- 238000010438 heat treatment Methods 0.000 claims abstract description 37
- 238000006243 chemical reaction Methods 0.000 claims abstract description 22
- 239000000126 substance Substances 0.000 claims abstract description 17
- 238000000605 extraction Methods 0.000 claims abstract description 16
- 238000002156 mixing Methods 0.000 claims abstract description 11
- 238000007254 oxidation reaction Methods 0.000 claims description 83
- 230000003647 oxidation Effects 0.000 claims description 75
- 230000003197 catalytic effect Effects 0.000 claims description 29
- 239000011232 storage material Substances 0.000 claims description 21
- 239000000047 product Substances 0.000 claims description 16
- 239000003054 catalyst Substances 0.000 claims description 9
- 239000007795 chemical reaction product Substances 0.000 claims description 9
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims description 8
- 239000000919 ceramic Substances 0.000 claims description 8
- 239000003546 flue gas Substances 0.000 claims description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 6
- 230000002269 spontaneous effect Effects 0.000 claims description 4
- 239000007800 oxidant agent Substances 0.000 claims 1
- 239000003245 coal Substances 0.000 abstract description 17
- 230000008569 process Effects 0.000 description 13
- 238000005516 engineering process Methods 0.000 description 12
- 230000008901 benefit Effects 0.000 description 7
- 230000000694 effects Effects 0.000 description 7
- 238000004146 energy storage Methods 0.000 description 7
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 6
- 239000000446 fuel Substances 0.000 description 6
- 238000005065 mining Methods 0.000 description 5
- 238000010248 power generation Methods 0.000 description 5
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- 229910002092 carbon dioxide Inorganic materials 0.000 description 3
- 239000001569 carbon dioxide Substances 0.000 description 3
- 238000000354 decomposition reaction Methods 0.000 description 3
- 238000011161 development Methods 0.000 description 3
- 238000004134 energy conservation Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 239000002803 fossil fuel Substances 0.000 description 2
- 239000005431 greenhouse gas Substances 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 239000012782 phase change material Substances 0.000 description 2
- 230000008092 positive effect Effects 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 238000012827 research and development Methods 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 239000002028 Biomass Substances 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
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- 238000005265 energy consumption Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 229910052987 metal hydride Inorganic materials 0.000 description 1
- 150000004681 metal hydrides Chemical class 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
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- 239000002910 solid waste Substances 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
- F28D20/00—Heat storage plants or apparatus in general; Regenerative heat-exchange apparatus not covered by groups F28D17/00 or F28D19/00
- F28D20/003—Heat storage plants or apparatus in general; Regenerative heat-exchange apparatus not covered by groups F28D17/00 or F28D19/00 using thermochemical reactions
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/14—Thermal energy storage
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Abstract
The invention belongs to the technical field of waste heat storage, and discloses a system and a method for thermochemically storing waste heat generated by methane combustion.A methane gas exhausted from a mine is mixed with an extraction gas exhausted from an extraction pump station to obtain a gas with required blending concentration, and the gas is uniformly mixed with fresh air and then is conveyed to a reactor; introducing the prepared ventilation air methane into a reactor and then burning, wherein the heat generated after burning provides reaction heat; the residual heat after the reaction is output to a thermochemical heat storage device by a heat exchanger and is used for heating a medium-high temperature thermochemical heat storage medium, and products are respectively stored; the heat stored in the form of chemical energy can be used for heating steam to drive a steam turbine to do work to generate power or heating buildings and residential areas. The invention adopts a thermochemical heat storage mode to store the waste heat which is difficult to utilize in time in a coal mine for a long time, and can quickly and conveniently release energy when energy is required.
Description
Technical Field
The invention belongs to the technical field of waste heat storage, and particularly relates to a system and a method for thermochemical heat storage by using methane combustion waste heat.
Background
Currently, methane is an important greenhouse gas, and its greenhouse effect is 21 times that of carbon dioxide. The reduction of emissions and the management of greenhouse gases other than carbon dioxide have not received sufficient international attention. The emission of methane mainly comes from the burning of fossil fuel and biomass, escape in the mining process of fossil fuel, treatment of solid waste and waste water and other processes. Wherein, a large amount of gas leaks into the atmosphere along with the ventilation of a mine in the coal mining process, and the methane concentration (0.1-1%) of the ventilation gas is lower than the lean-burn lower limit, so that the ventilation gas cannot be directly utilized.
Based on the current situation that coal is still used as a main energy supply form for a long time in the future of China, the ventilation gas with huge emission is effectively treated, and the high-heat-value hidden resource of methane can be utilized, and the greenhouse effect brought by the ventilation gas can be relieved. The utilization technology of low-concentration methane can be mainly divided into utilization of methane as a main fuel and utilization of methane as an auxiliary fuel. Since the low concentration methane as a secondary fuel has an uncontrolled heat release and contains a large amount of impurities that affect the operation of the turbine, it is more feasible to convert the low concentration methane gas as a primary fuel than as a secondary fuel. When low-concentration methane is used as a main fuel, the direct oxidation method of the ventilation gas can be mainly classified into a thermal oxidation method and a catalytic oxidation method. The high temperature reaction process of thermal oxidation usually reaches over 1000 ℃, which consumes a lot of energy. The catalytic oxidation utilizes the catalyst to reduce the oxidation temperature of methane, and only needs to preheat a catalyst bed layer to 500 ℃, thereby saving a large amount of electric energy. The combustion mechanism of methane can be seen in the following equation:
CH 4 +2O 2 →CO 2 +H 2 OΔH＝-802.7kJ/mol
the residual heat after the mine ventilation air is combusted can be utilized in various ways, for example, the residual heat is utilized for heating, and the residual heat is used for heating a residual heat boiler to generate steam for providing hot water for a mining area outside the condition that the methane oxidation device keeps self operation. The waste heat can be used for generating power, and the hot flue gas generated by the oxidation device is used for heating a waste heat boiler to push a steam turbine to do work for power generation. The generated electric energy can be used for the mining area, and can be output in a grid-connected mode when the generated energy is large. The gas escaping from the mine can form a heat and power cogeneration mode of heating in winter and power generation in other seasons, so that the gas is fully utilized.
The waste heat utilization technology of ventilation gas has rapidly developed in recent years, and a disposal system combining utilization technologies of various concentrations, such as power generation of an internal combustion engine, heat storage oxidation, direct combustion, gas purification and the like is formed. However, the waste heat utilization of the ventilation gas needs to be made according to local conditions, and if the waste heat utilization is not performed in a coal mining area, a large amount of heat generated by combustion of low-concentration methane can be wasted. The efficient utilization of low-concentration and ultra-low-concentration gas is limited by technology and economy, and the utilization of coal mine gas is always a short plate, and particularly the direct combustion technology of the low-concentration gas is still in an industrial test stage. The safe combustion device is successfully tested in coal mines such as Jincheng village and the like, and fills the technical blank in the field of directly utilizing low-concentration gas. The large-area popularization of the low-concentration gas direct combustion technology, the full-concentration utilization of methane and the loss of related safety production laws and regulations limit the utilization of the coal mine ventilation gas to a certain extent. At present, waste heat power generation of ventilation gas is also subjected to the problems that the grid connection approval period is too long, the approval procedure is complicated, and a generator set cannot work normally after the heating season comes. Before the point-shaped distributed power grid connection can be implemented in a large scale and high efficiency manner, the storage of the waste heat generated after the coal mine ventilation gas is combusted has double meanings of energy conservation and emission reduction.
The heat storage technology is an important field of energy storage technology, and is divided into sensible heat storage, latent heat storage and thermochemical heat storage according to the types of heat storage materials. Sensible heat storage utilizes the specific heat capacity of the material itself to store and release heat through temperature changes of the material. The energy storage density of the heat storage mode is very low, and the heat storage mode can only be applied to a specific temperature area. Latent heat storage utilizes phase change of a material to store and release heat. The energy storage density of the heat storage mode is improved to a certain extent compared with sensible heat storage, but the phase change material has high corrosivity, low heat conductivity and low heat efficiency. The development of the third generation heat storage technology, i.e. thermochemical heat storage, is driven by the drawbacks of sensible heat storage and latent heat storage. Thermochemical heat storage utilizes reversible chemical reactions to store and release heat, the energy storage density of which is the greatest among the three modes, and long-term and low-loss storage of heat can be realized through electrostatic attraction between chemical bonds, and the heat storage mode is still in a development stage. The thermochemical heat storage materials are various in types, and can be specifically classified into metal hydride systems, metal oxide systems, hydroxide systems, carbonate systems, ammonia systems, and organic systems. Therefore, the thermochemical heat storage material covers a medium-high temperature reaction temperature range which can span 300-1100 ℃, and the combination of thermochemical heat storage and the waste heat utilization of ventilation air methane can meet the waste heat utilization scenes of various ventilation air methane combustion modes.
Through the above analysis, the problems and defects of the prior art are as follows:
(1) The existing sensible heat storage mode has low energy storage density and can only be applied to a specific temperature area.
(2) The phase change material of the existing latent heat storage mode has the defects of high corrosivity, low heat conductivity and low heat efficiency.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides a system and a method for thermochemical heat storage by using methane combustion waste heat. The heat storage mode of thermochemistry heat storage can solve the problem of waste heat waste in the technical scheme, and the invention is equivalent to a new application scene for thermochemistry heat storage. The heat storage technology is applied to the fields of clean heating, thermal power flexibility improvement, power peak regulation, renewable energy consumption and the like, and has an industrial foundation.
Although thermochemical heat storage is not the way this invention has been developed. However, the invention provides a novel application scenario of thermochemical heat storage, and the thermochemical heat storage has not yet realized real industrial application at present, and the research of finding suitable heat storage materials and developing reactors in the prior art is in progress. No specific application is made.
The invention is realized in such a way that a method for thermochemically storing heat by using waste heat generated by methane combustion comprises the following steps:
firstly, mixing ventilation air methane discharged by a mine with extracted gas discharged by an extraction pump station to obtain gas with required blending concentration, uniformly mixing the gas with fresh air, and conveying the gas to a reactor;
step two, introducing the prepared ventilation air methane into a reactor and then burning, wherein the heat generated after burning provides the heat of subsequent self reaction, and the redundant heat is stored;
outputting the residual heat after the reaction to a thermochemical heat storage device by using a heat exchanger, and heating a medium-high temperature thermochemical heat storage medium to enable the medium-high temperature thermochemical heat storage medium to absorb energy to generate chemical bond fracture so as to generate decomposition reaction, and respectively storing decomposition products;
and step four, when energy is required, performing synthetic reaction on the decomposition product, and releasing heat stored in a chemical energy form to heat steam to push a steam turbine to do work to generate power or to heat buildings and residential areas.
Further, when the reactor is a catalytic oxidation device, the method for using the methane combustion waste heat for thermochemical heat storage specifically comprises the following steps:
(1) The concentration of ventilation air methane discharged by a mine is mixed with extracted gas discharged by an extraction pump station to obtain gas with required concentration, and the gas is uniformly mixed with fresh air and then conveyed to a catalytic oxidation device;
(2) The mixed ventilation air methane is introduced into a catalytic oxidation device, the temperature of methane combustion is greatly reduced by a catalyst bed layer in the reactor, the ventilation air methane is heated to the oxidation temperature by a heat storage material in the device, and oxidation reaction is carried out in the reactor and heat is released;
(3) Part of heat generated by the combustion of the ventilation air methane is stored in the heat storage material for continuous oxidation of low-concentration methane, and the surplus heat is output outwards for thermochemical heat storage;
(4) The temperature of the waste heat released by catalytic oxidation is low, so that the waste heat released by catalytic oxidation combustion of ventilation air methane is used for heating medium-low temperature thermochemical heat storage media, products are stored respectively, and when energy is required, the reaction products are introduced into the same thermochemical heat release reactor to perform heat release reaction to release the stored waste heat;
a typical thermochemical heat storage apparatus comprises two reactors, one for the endothermic reaction and the other for the exothermic reaction.
(5) The heat stored in the form of chemical energy can be used for heating steam to drive a steam turbine to do work to generate power or heating buildings and residential areas.
Further, the redundant heat in the step (3) is output outwards in the form of middle-temperature smoke at 300-600 ℃.
Further, the medium-low temperature thermochemical heat storage medium in the step (4) may be selected from Ca (OH) which is representative of the medium-low temperature thermochemical heat storage medium 2 The products are CaO and water vapor. Other middle and low temperature thermochemical heat storage media (e.g. Mg (OH) 2 /MgO、CaH 2 、MgH 2 ) May also be used in the system.
Further, when the reactor is a thermal oxidation device, the method for thermochemically storing heat by using the methane combustion waste heat specifically comprises the following steps:
(1) The concentration of ventilation air methane discharged by a mine is mixed with extracted gas discharged by an extraction pump station to obtain gas with required concentration, and the gas is uniformly mixed with fresh air and then conveyed to a thermal oxidation device;
(2) The mixed ventilation air methane is introduced into a thermal oxidation device, and the ventilation air methane is heated to the spontaneous combustion temperature of methane by the preheated heat storage material so as to be subjected to oxidation reaction to release heat;
(3) Part of heat generated by the combustion of the ventilation air methane is stored in the heat storage material for continuous oxidation of low-concentration methane, and the surplus heat is output outwards for thermochemical heat storage;
(4) The waste heat released by thermal oxidation is high in temperature, so that the waste heat released by thermal oxidation combustion of ventilation air methane is used for heating medium-high temperature thermochemical heat storage media, reaction products are stored respectively, and when energy is required, the reaction products are introduced into the same reactor to perform exothermic reaction to release the stored waste heat;
(5) The heat stored in the form of chemical energy can heat steam to drive a steam turbine to do work to generate power or heat buildings and residential areas.
Further, the redundant heat in the step (3) is output outwards in the form of high-temperature flue gas at 600-1000 ℃.
Further, representative CaCO can be selected as the medium-low temperature thermochemical heat storage medium in the step (4) 3 The products are CaO and CO 2 . Other medium-high temperature thermo-chemical heat storage media (e.g. Co) 3 O 4 /CoO、CaMnO 3-δ ) May also be used in the system.
Another object of the present invention is to provide a system for thermochemically storing heat by using residual heat from methane combustion, which comprises:
a reactor and a thermochemical heat storage device;
a heat exchanger is arranged in the reactor, heat storage ceramics are respectively arranged on the upper side and the lower side of the heat exchanger, and the heat exchanger is connected with a thermochemical heat storage device on the outer side through a connecting pipeline;
and a heat storage medium is filled in the thermochemical heat storage device.
Further, the side surface of the reactor is communicated with an extraction pump station, and the reactor is a catalytic oxidation device or a thermal oxidation device.
Further, a catalyst is sandwiched between the heat exchanger and the heat storage ceramic in the catalytic oxidation device.
In combination with the technical solutions and the technical problems to be solved, please analyze the advantages and positive effects of the technical solutions to be protected in the present invention from the following aspects:
first, aiming at the technical problems and difficulties in solving the problems in the prior art, the technical problems to be solved by the technical scheme of the present invention are closely combined with results, data and the like in the research and development process, and some creative technical effects are brought after the problems are solved. The specific description is as follows:
the coal mine ventilation air methane oxidation combustion has important significance of energy conservation and emission reduction, has good social benefit by reasonably and effectively utilizing the heat generated after the ventilation air methane is combusted, and has promotion effect on the sustainable production of coal mines and the treatment of coal mine gas by the nation. The novel heat storage mode of thermochemistry heat storage can store the waste heat which is difficult to utilize in time in a coal mine for a long time, and replaces the prior operation mode of directly discharging or wasting the high-quality heat. The heat stored by chemical energy can theoretically realize infinite transportation distance, theoretically has no heat loss, and can quickly and conveniently release energy when energy is needed.
Secondly, considering the technical scheme as a whole or from the perspective of products, the technical effect and advantages of the technical scheme to be protected by the invention are specifically described as follows:
when the waste heat generated by burning the low-concentration methane generated in the coal mine is difficult to be utilized in time, the waste heat utilization and the thermochemical heat storage technology are combined, the heat storage is utilized to drive the popularization and the propagation of the utilization of the low-concentration gas in the coal mine, the promotion effect is provided for the safe production and the sustainable development of the coal mine, and meanwhile, the high economic benefit and the high environmental benefit are achieved.
Third, as the inventive supplementary proof of the claims of the present invention, the expected profit and commercial value after the technical solution of the present invention is transformed are:
the system for the thermochemical heat storage of the waste heat of methane combustion in the invention is analyzed in economy, and assuming that the percentage of methane required for maintaining the self-heating combustion is 0.2 percent, the energy which cannot be utilized and is lost is 8 percent, and the residual heat is conveyed to the heat storage system for storage. The total processing capacity of a ventilation air methane processing station of a certain coal mine is set as 10 6 m 3 H, the throughput of a single fan is 10 5 m 3 And h, 10 fans are equipped. According to engineering experience and common technical parameters, the calorific value of the methane is 37.26MJ/m 3 The methane concentration in the ventilation gas was adjusted to 1%, and the gas oxidation rate was set to 96%.
The total heat generated after the oxidation of the ventilation gas is as follows:
37.26×10 6 ×1％×96％＝357696MJ/h
the heat required by the ventilation gas to maintain self combustion is as follows:
37.26×10 6 ×0.2％＝74520MJ/h
the unused heat is:
37.26×10 6 ×1％×96％×8％＝28615.68MJ/h
the amount of heat that can be stored is:
357696-74520-28615.68＝254560.32MJ/h＝70711200kW
the efficiency of the energy storage system is 98%, a boiler with rated design parameters of 540 ℃ and 9.8MPa is adopted for power generation, and the corresponding steam enthalpy value is 3478.98kJ/kg. The boiler feed water parameters are selected to be 12.5MPa and 110 ℃, and the corresponding feed water enthalpy is 470.43kJ/kg, and the corresponding steam enthalpy drop is 3008.55kJ/kg. The heat exchange efficiency in the boiler is selected to be 90%.
The steam yield of the waste heat boiler is as follows:
254560.32×98％×90％÷3008.55＝74.63t/h。
the economic analysis can show that the application of the heat storage technology to the waste heat utilization of the mine ventilation air oxidation has important significance in energy conservation and emission reduction. When the concentration of methane is 1 percent, the ventilation air methane treatment capacity is 10 percent 6 m 3 Annual utilization of pure methane at a time of/h is as high as 1600 km 3 And the reduced carbon dioxide emission is up to 22 ten thousand t. The energy stored in the energy storage system can be as high as 4 multiplied by 10 each year 8 MJ, equivalent to 13637t coal.
Drawings
FIG. 1 is a flow chart of a method for thermochemically storing heat by utilizing waste heat from methane combustion according to an embodiment of the present invention;
FIG. 2 is a process flow diagram of the application of the waste heat after catalytic oxidation combustion of ventilation air methane to a thermochemical heat storage process according to an embodiment of the present invention;
FIG. 3 is a flow chart of a thermal chemical heat storage process using waste heat from thermal oxidation combustion of ventilation air methane according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
1. Illustrative embodiments are explained. This section is an explanatory embodiment expanding on the claims so as to fully understand how the present invention is embodied by those skilled in the art.
As shown in fig. 1, the method for thermochemically storing heat by using residual heat from methane combustion provided by the embodiment of the present invention includes:
s101, mixing ventilation air methane discharged by a mine with extracted gas discharged by an extraction pump station to obtain gas with required blending concentration, uniformly mixing the gas with fresh air, and conveying the gas to a reactor;
s102, introducing the prepared ventilation air methane into a reactor for combustion, wherein the heat generated after combustion provides reaction heat;
s103, outputting the residual heat after the reaction to a thermochemical heat storage device by using a heat exchanger, heating medium-high temperature thermochemical heat storage media, and respectively storing the products;
and S104, heating the subsequent steam by using the heat stored in the chemical energy form to drive a steam turbine to do work to generate power or to heat buildings and residential areas.
As a preferred embodiment of the present invention, when the reactor is a catalytic oxidation device, the method for thermochemically storing heat by using the waste heat of methane combustion specifically comprises:
(1) The concentration of ventilation air methane discharged by a mine is mixed with extracted gas discharged by an extraction pump station to obtain gas with required concentration, and the gas is uniformly mixed with fresh air and then conveyed to a catalytic oxidation device;
(2) The mixed ventilation air methane is introduced into a catalytic oxidation device, the temperature of methane combustion is greatly reduced by a catalyst bed layer in the reactor, the ventilation air methane is heated to the oxidation temperature by a heat storage material in the device, and oxidation reaction is carried out in the reactor and heat is released;
(3) Part of heat generated by the combustion of the ventilation air methane is stored in the heat storage material for continuous oxidation of low-concentration methane, and the surplus heat is output outwards for thermochemical heat storage;
(4) Because the temperature of the waste heat released by catalytic oxidation is low, the waste heat released by catalytic oxidation combustion of ventilation air methane is used for heating a medium-low temperature thermochemical heat storage medium, products are stored respectively, and when energy is required, the reaction products are introduced into the same thermochemical heat release reactor to perform heat release reaction to release the stored waste heat;
(5) The heat stored in the form of chemical energy can heat steam to drive a steam turbine to do work to generate power or heat buildings and residential areas.
As a preferred embodiment of the invention, the excessive heat in the step (3) is output outwards in the form of middle-temperature flue gas at 300-600 ℃.
As a preferred embodiment of the present invention, the medium/low temperature thermochemical heat storage medium in the step (4) is typically Ca (OH) 2 The products are CaO and water vapor. Other middle and low temperature thermochemical heat storage media (e.g. Mg (OH) 2 /MgO、CaH 2 、MgH 2 ) May also be used in the system.
As a preferred embodiment of the present invention, when the reactor is a thermal oxidation device, the method for thermochemically storing heat by using the residual heat from methane combustion specifically includes:
(1) The concentration of ventilation air methane exhausted by a mine is mixed with the extracted gas exhausted by an extraction pump station to obtain gas with required concentration, and the gas is uniformly mixed with fresh air and then conveyed to a thermal oxidation device;
(2) Introducing the mixed ventilation air methane into a thermal oxidation device, and heating the ventilation air methane to the spontaneous combustion temperature of methane by the preheated heat storage material so as to perform oxidation reaction to release heat;
(3) Part of heat generated by the combustion of the ventilation air methane is stored in the heat storage material for continuous oxidation of low-concentration methane, and the surplus heat is output outwards for thermochemical heat storage;
(4) The waste heat released by thermal oxidation is high in temperature, so that the waste heat released by thermal oxidation combustion of ventilation air methane is used for heating medium-high temperature thermochemical heat storage media, reaction products are stored respectively, and when energy is required, the reaction products are introduced into the same reactor to perform exothermic reaction to release the stored waste heat;
(5) The heat stored in the form of chemical energy can be used for heating steam to drive a steam turbine to do work to generate power or heating buildings and residential areas.
And (4) outputting the redundant heat in the step (3) outwards in the form of high-temperature flue gas at 600-1000 ℃.
The representative CaCO can be selected as the medium-low temperature thermochemical heat storage medium in the step (4) 3 The products are CaO and CO 2 . Other medium-high temperature thermochemical heat storage media (e.g. Co) 3 O 4 /CoO、CaMnO 3-δ ) May also be used in the system.
The embodiment of the invention also provides a system for thermochemically storing heat by using methane combustion waste heat, which comprises:
a reactor and a thermochemical heat storage device;
a heat exchanger is arranged in the reactor, heat storage ceramics are respectively arranged on the upper side and the lower side of the heat exchanger, and the heat exchanger is connected with a thermochemical heat storage device on the outer side through a connecting pipeline;
and a heat storage medium is filled in the thermochemical heat storage device.
The side surface of the reactor in the embodiment of the invention is communicated with an extraction pump station, and the reactor is a catalytic oxidation device or a thermal oxidation device.
The catalyst is sandwiched between the heat exchanger and the heat storage ceramic in the catalytic oxidation device in the embodiment of the invention.
2. Evidence of the relevant effects of the examples. The embodiment of the invention has some positive effects in the process of research and development or use, and indeed has great advantages compared with the prior art, and the following contents are described by combining data, charts and the like in the test process.
Example 1:
as shown in fig. 2, it is a process flow chart of applying the waste heat after catalytic oxidation combustion of ventilation air methane to a thermochemical heat storage process, and the process steps are as follows:
(1) The concentration of ventilation air methane discharged by a mine is usually lower (less than 0.5%), and the ventilation air methane is mixed with extracted gas discharged by an extraction pump station to obtain gas with required blending concentration (1.2% in the example), and the gas is uniformly mixed with fresh air and then is conveyed to a catalytic oxidation device;
(2) The mixed ventilation air methane is introduced into a catalytic oxidation device, and the temperature of methane combustion can be greatly reduced by a catalyst bed layer in the reactor. The ventilation air methane is heated to oxidation temperature by a heat storage material (generally ceramic) in the device, oxidation reaction is carried out in the reactor, and heat is released;
(3) Part of heat generated by the combustion of the ventilation air methane is stored in the heat storage material for continuous oxidation of low-concentration gas, and the redundant heat is output outwards in the form of medium-temperature flue gas at 300-600 ℃ for thermochemical heat storage;
(4) The waste heat released by the catalytic oxidation combustion of the ventilation air methane is used for heating the medium-low temperature thermochemical heat storage medium (in the example, a typical medium-temperature heat storage medium is selected: ca (OH) 2 CaO), the product CaO and steam are stored separately. When energy is required, caO and steam are introduced into the same reactor to perform exothermic reaction to release the stored waste heat;
(5) The heat stored in the form of chemical energy can be used for heating steam to drive a steam turbine to do work to generate power or heating buildings and residential areas.
Example 2
As shown in fig. 3, it is a process flow chart of applying the waste heat after thermal oxidation combustion of ventilation air methane to a thermochemical heat storage process, and the flow steps are as follows:
(1) The concentration of ventilation air methane exhausted by a mine is usually lower (less than 0.5%), and the ventilation air methane is mixed with extracted gas exhausted by an extraction pump station to obtain gas with required blending concentration (1.2% in the embodiment), and the gas is uniformly mixed with fresh air and then is conveyed to a thermal oxidation device;
(2) The mixed ventilation air methane is introduced into a thermal oxidation device, and the preheated heat storage material (generally ceramic) heats the ventilation air methane to the spontaneous combustion temperature (about 1000 ℃) of methane so as to carry out oxidation reaction to release heat. Compared with catalytic oxidation, the oxidation mode consumes higher energy, and the volume of the heat storage material is larger;
(3) Part of heat generated by the combustion of the ventilation air methane is stored in the heat storage material for continuous oxidation of low-concentration methane, and the redundant heat is output outwards in the form of high-temperature flue gas at 600-1000 ℃ for thermochemical heat storage;
(4) The waste heat released by the thermal oxidation combustion of the ventilation air methane is used for heating medium-high temperature thermochemical heat storage medium (the example selects typical high-temperature heat storage medium: caCO) 3 CaO), the products CaO and CO 2 And respectively storing. When energy is needed, caO and CO are added 2 Introducing the waste heat into the same reactor to perform exothermic reaction and release the stored waste heat;
(5) The heat stored in the form of chemical energy can be used for heating steam to drive a steam turbine to do work to generate power or heating buildings and residential areas.
The above description is only for the purpose of illustrating the present invention and the appended claims are not to be construed as limiting the scope of the invention, which is intended to cover all modifications, equivalents and improvements that are within the spirit and scope of the invention as defined by the appended claims.
Claims (10)
1. A method for thermochemically storing heat by using residual heat from methane combustion, which is characterized by comprising the following steps:
mixing ventilation air methane discharged by a mine with extracted gas discharged by an extraction pump station to obtain gas with required concentration, uniformly mixing the gas with fresh air, and conveying the gas to a reactor;
introducing the mixed ventilation air methane into the reactor and then combusting, wherein the heat generated after combustion provides reaction heat;
the residual heat after the reaction is output to a thermochemical heat storage device by a heat exchanger and is used for heating a medium-high temperature thermochemical heat storage medium, and products are respectively stored;
the heat stored in the form of chemical energy can be used for heating steam to drive a steam turbine to do work to generate power or heating buildings and residential areas.
2. The method for thermochemically storing heat from residual heat of combustion of methane as set forth in claim 1, wherein when the reactor is a catalytic oxidation device, the method for thermochemically storing heat from residual heat of combustion of methane specifically comprises:
(1) The concentration of ventilation air methane discharged by a mine is mixed with extracted gas discharged by an extraction pump station to obtain gas with required concentration, and the gas is uniformly mixed with fresh air and then conveyed to a catalytic oxidation device;
(2) The mixed ventilation air methane is introduced into a catalytic oxidation device, the temperature of methane combustion is greatly reduced by a catalyst bed layer in the reactor, the ventilation air methane is heated to the oxidation temperature by a heat storage material in the device, and oxidation reaction is carried out in the reactor and heat is released;
(3) Part of heat generated by the combustion of the ventilation air methane is stored in the heat storage material for continuous oxidation of low-concentration methane, and the surplus heat is output outwards for thermochemical heat storage;
(4) The temperature of the waste heat released by catalytic oxidation is low, so that the waste heat released by catalytic oxidation combustion of ventilation air methane is used for heating medium-low temperature thermochemical heat storage media, products are stored respectively, and when energy is required, the reaction products are introduced into the same thermochemical heat release reactor to perform heat release reaction to release the stored waste heat;
(5) The heat stored in the form of chemical energy can be used for heating steam to drive a steam turbine to do work to generate power or heating buildings and residential areas.
3. The method for thermochemically storing heat by utilizing waste heat from methane combustion as claimed in claim 2, wherein the excess heat in step (3) is outputted in the form of middle-temperature flue gas at 300-600 ℃.
4. The method for thermochemically storing heat from methane combustion as recited in claim 2 wherein the medium-low temperature thermochemical heat storage medium in step (4) is selected from Ca (OH) 2 The products are CaO and water vapor; the rest medium-low temperature thermochemical heat storage medium is utilized.
5. The method for thermochemically storing heat from combustion of methane as set forth in claim 1, wherein when the reactor is a thermal oxidizer, the method for thermochemically storing heat from combustion of methane comprises:
(1) The concentration of ventilation air methane discharged by a mine is mixed with extracted gas discharged by an extraction pump station to obtain gas with required concentration, and the gas is uniformly mixed with fresh air and then conveyed to a thermal oxidation device;
(2) The mixed ventilation air methane is introduced into a thermal oxidation device, and the ventilation air methane is heated to the spontaneous combustion temperature of methane by the preheated heat storage material so as to be subjected to oxidation reaction to release heat;
(3) Part of heat generated by the combustion of the ventilation air methane is stored in the heat storage material for continuous oxidation of low-concentration methane, and the surplus heat is output outwards for thermochemical heat storage;
(4) The waste heat released by thermal oxidation is high in temperature, so that the waste heat released by thermal oxidation combustion of ventilation air methane is used for heating medium-high temperature thermochemical heat storage media, reaction products are stored respectively, and when energy is required, the reaction products are introduced into the same reactor to perform exothermic reaction to release the stored waste heat;
(5) The heat stored in the form of chemical energy can be used for heating steam to drive a steam turbine to do work to generate power or heating buildings and residential areas.
6. The method for thermochemically storing heat by utilizing waste heat from methane combustion as claimed in claim 5, wherein the excess heat in step (3) is outputted in the form of high temperature flue gas at 600-1000 ℃.
7. The method for thermochemically storing heat from residual heat of methane combustion as claimed in claim 5, wherein the representative CaCO is selected as the medium-low temperature thermochemical heat storage medium in the step (4) 3 The products are CaO and CO 2 (ii) a And other medium-high temperature thermochemical heat storage media are utilized.
8. A system for implementing the method for thermochemically storing heat by using residual heat from methane combustion as set forth in any one of claims 1 to 7, wherein the system for thermochemically storing heat by using residual heat from methane combustion comprises:
a reactor and a thermochemical heat storage device;
a heat exchanger is arranged in the reactor, heat storage ceramics are respectively arranged on the upper side and the lower side of the heat exchanger, and the heat exchanger is connected with a thermochemical heat storage device on the outer side through a connecting pipeline;
and a heat storage medium is filled in the thermochemical heat storage device.
9. The system for utilizing the methane combustion waste heat for thermochemical heat storage according to claim 8, wherein the side of the reactor is communicated with an extraction pump station, and the reactor is a catalytic oxidation device or a thermal oxidation device.
10. The system for thermochemical heat storage using residual heat from methane combustion as set forth in claim 8, wherein a catalyst is sandwiched between the heat exchanger and the heat storage ceramic in the catalytic oxidation apparatus.
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| US20110250115A1 (en) * | 2008-12-17 | 2011-10-13 | Shengli Oilfield Shengli Power Machinery Co., Ltd. | Method and abatement device to destroy low-concentration coalmine methane |
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