Background
With the centralized production and treatment of agricultural land in China, the reduction of rural population and the reduction of straw combustion, the yield of agricultural biomass solid waste is increased, the requirement on the environment-friendly treatment of livestock and poultry wastes is improved, and the biomass fermentation is the most effective treatment mode at the present stage. Biomass fermentation produces biogas, which is a very high quality fuel, but many fermentation production places and projects are far away from industrial gas users, gas production and gas use are unbalanced, and the direct discharge of the produced gas into the air causes a significant environmental problem because biogas is a greenhouse gas equivalent to 21 times stronger carbon dioxide, and the direct discharge can aggravate the greenhouse effect. Only a few large-scale fermentation projects can ensure the utilization of the produced gas through power on-line, and the comprehensive utilization efficiency of energy is not high (the efficiency of gas power generation is only more than 30 percent, and the rest is discharged along with flue gas).
Since the biogas cannot be directly used by a user, if a large amount of biogas is generated, the inside of the biogas cannot be completely used, air and fuel are inevitable, and thus, huge waste is generated and environmental problems are caused.
Liquefied Natural Gas (LNG), the main component of which is methane, is known as the cleanest fossil energy on earth. The liquefied natural gas is colorless, tasteless, nontoxic and noncorrosive, the volume of the liquefied natural gas is about 1/625 of the volume of the same amount of gaseous natural gas, and the mass of the liquefied natural gas is only about 45 percent of the same volume of water.
The manufacturing process is that natural gas is purified and is produced after being liquefied at a series of ultralow temperatures. After the liquefied natural gas is combusted, the pollution to the air is very small, and the heat emitted by the liquefied natural gas is large, so the liquefied natural gas is a relatively advanced energy source.
The liquefied natural gas is liquid after being compressed and cooled to the condensation point (-161.5 ℃), and is usually stored in a low-temperature storage tank at-161.5 ℃ and about 0.1MPa, transported by a special ship or an oil tank truck and re-gasified when in use. Since the 70 s of the 20 th century, the world production and trade volume of liquefied natural gas has increased rapidly, and in 2019, the global demand for LNG has increased by 12.5% to 3.59 hundred million tons on a par, and the global supply volume of LNG has increased by 4000 ten thousand tons, creating new records of the industry, and these new supply volumes are digested by the market.
LNG is popularized and used in environment-friendly advanced countries in the world, and besides being used as fuel of power plants, factories and household users, methane contained in the LNG can be used as chemical raw materials for manufacturing fertilizers, methanol solvents, synthetic acetic acid and the like; in addition, the contained ethane and propane can be cracked to generate ethylene and propylene, which are important raw materials of plastic products.
The most important advantages of LNG are that the transportation is simple, the transportation amount is large, the technology and equipment are mature, and the cold energy can be recycled on the user side.
SUMMERY OF THE UTILITY MODEL
To produce electric power and be difficult to externally export, the great biological natural gas of scale is difficult to the not enough that uses from producing among the prior art, the utility model aims at providing a biological natural gas multi-mode energy supply system can be to external defeated biological natural gas and electric power, and cold and hot electricity of inside supply and steam, externally export LNG, have still realized the high-efficient comprehensive utilization to the energy simultaneously, and the flue gas heat energy after electricity generation or the burning is retrieved and is generated electricity once more or prepare cold and hot, and energy-concerving and environment-protective effect is showing.
In order to achieve the above purpose, the utility model adopts the following technical scheme:
a multi-mode energy supply system for biological natural gas is provided with biological natural gas fermentation equipment, desulfurization purification equipment, a natural gas storage container, a biological natural gas boiler, a biological natural gas generator set I, a biological natural gas generator set II, a waste heat boiler, a steam generator set, an absorption refrigerator, cooling LNG preparation equipment, an LNG storage container, a dry ice storage container, a cold storage device, a biological natural gas burner, a cold user, a heat user, a steam process line, a high-temperature phase change heat storage container and a low-temperature heat storage container in a set range;
the biogas outlet of the biogas fermentation equipment is communicated with the inlet of the desulfurization and purification equipment, and the outlet of the desulfurization and purification equipment is connected with the inlet of the biogas storage container through a biogas valve; an outlet of the biological natural gas storage container is communicated with the cooling preparation LNG equipment through a biological natural gas valve eighth, the cooling preparation LNG equipment is respectively communicated with the LNG storage container and the dry ice storage container, the LNG storage container is used for conveying LNG to an LNG user or LNG transportation and storage equipment, and the dry ice storage container is used for conveying dry ice to the dry ice user or dry ice transportation and storage equipment;
the outlet of the desulfurization and purification equipment is also communicated with a biogas burner through a biogas valve IV, and the biogas burner is used for burning by taking biogas as fuel so as to supply heat to a biogas boiler; the outlet of the biogas storage container is respectively communicated with the biogas generator set I and the biogas generator set II and is used for supplying biogas required by power generation to the biogas generator set I and the biogas generator set II according to power consumption requirements;
the biogas storage container is communicated with a main road, the main road is respectively communicated with a first branch road and a second branch road, the first branch road and the second branch road are respectively communicated with a biogas gas generator set I and a biogas gas generator set II, a biogas valve III is arranged on the main road, a biogas valve V is arranged on the first branch road, a biogas valve VI is arranged on the second branch road, and the biogas valve V and the biogas valve VI are respectively communicated with gas inlets of the biogas gas generator set I and the biogas gas generator set II; the outlet of the desulfurization and purification equipment is also respectively communicated with the biological natural gas valve five and the biological natural gas valve six through a biological natural gas valve two;
the biological natural gas boiler, the first biological natural gas generator set and the second biological natural gas generator set are connected to the waste heat boiler and used for conveying the discharged flue gas to the waste heat boiler so that the waste heat boiler can utilize heat in the flue gas for heating;
the biological natural gas boiler and the waste heat boiler are communicated with the high-temperature phase-change heat storage container, the steam utilization process line, the steam generator set, the low-temperature heat storage container, the heat utilization user and the absorption refrigerator and are used for conveying steam to the high-temperature phase-change heat storage container, the steam utilization process line, the steam generator set, the low-temperature heat storage container, the heat utilization user and the absorption refrigerator according to the steam utilization or power utilization requirements; the absorption refrigerator is used for supplying cold to a cold user or storing cold by using the cold storage device;
a steam outlet of the biological natural gas boiler is sequentially communicated with a first steam valve and a second steam valve, and an outlet of the second steam valve is communicated with the steam process line; an outlet of the first steam valve is communicated with the high-temperature phase change heat storage container and a fourth steam valve respectively, and an outlet of the fourth steam valve is communicated with a steam inlet of the steam generator set; an extraction outlet of the steam generator set is communicated with the steam utilization process line through an extraction valve and is used for conveying steam extracted from the steam generator set to the steam utilization process line; a steam outlet of the waste heat boiler is respectively communicated with a steam valve III and a steam valve V, the steam valve V is communicated with the heat user and the low-temperature heat storage container, and the steam valve III is respectively communicated with the high-temperature phase change heat storage container, a steam valve IV and a steam valve II; and a waste steam outlet of the steam generator set is communicated with the absorption refrigerator through a waste steam hot valve I and is communicated with the heat utilization user and the low-temperature heat storage container through a waste steam hot valve II, the waste steam hot valve II is also respectively communicated with a steam valve V and the waste steam hot valve I, and the waste steam hot valve II adopts a two-way valve.
Furthermore, the system also comprises flue gas purification equipment, and the flue gas outlets of the biological natural gas boiler and the waste heat boiler are communicated with the flue gas purification equipment.
Further, in the above system, the biogas gas generator set includes a biogas engine i and a generator i, the biogas engine i is connected to the generator and provides power for the generator i; a fuel gas inlet of the first biogas engine is respectively communicated with outlets of the desulfurization and purification equipment and the biogas storage container and is used for obtaining biogas from the desulfurization and purification equipment and/or the biogas storage container according to gas use requirements; and a smoke outlet of the first biogas engine is connected to the waste heat boiler and used for conveying the exhausted smoke to the waste heat boiler so that the waste heat boiler can utilize heat in the smoke for heating.
Further, in the system, the biogas gas generator set II comprises a biogas engine II and a generator II, and the biogas engine II is connected with the generator II and provides power for the generator II; a fuel gas inlet of the biogas engine II is respectively communicated with outlets of the desulfurization and purification equipment and the biogas storage container and is used for obtaining biogas from the desulfurization and purification equipment and/or the biogas storage container according to gas use requirements; and a smoke outlet of the biogas engine II is connected to the waste heat boiler and used for conveying the discharged smoke to the waste heat boiler so that the waste heat boiler can utilize heat in the smoke for heating.
Further, in the above system, the steam generator set includes a steam turbine and a third generator, the steam turbine is connected to the third generator and provides power for the third generator, and a steam inlet of the steam turbine is communicated with the biological natural gas boiler and the exhaust-heat boiler, and is used for obtaining high-temperature steam from the biological natural gas boiler and/or the exhaust-heat boiler according to power demand.
The beneficial effects of the utility model reside in that: utilize the utility model discloses, in fermentation place of production or project within range, can not be to outer defeated biogas and electric power, the cold and hot electricity of inside supply and steam, external output LNG, still realized the high-efficient comprehensive utilization to the energy simultaneously, the flue gas heat energy after electricity generation or the burning is retrieved and is generated electricity once more or prepare cold and hot, and energy-concerving and environment-protective effect is showing. The reasonable and efficient utilization and safety of the biogas in a single project under the conditions of production, variable-time production and unbalanced use are fully ensured, frequent starting and fluctuation in the aspects of power generation and LNG preparation are reduced based on multiple energy storage modes, energy conservation, environmental protection, economic safety and closed loop of production, use, output (LNG supply) of the biogas and power generation and use are finally realized by coupling multiple application scenes and energy storage technologies.
Detailed Description
The present invention will be further described with reference to the accompanying drawings, and it should be noted that the present embodiment is based on the technical solution, and the detailed embodiments and the specific operation processes are provided, but the protection scope of the present invention is not limited to the present embodiment.
Example 1
The present embodiment provides a multi-mode energy supply system for biogas, as shown in fig. 1, a biogas fermentation device 1, a desulfurization purification device 2, a natural gas storage container 3, a biogas boiler 4, a biogas gas generator set one, a biogas gas generator set two, a waste heat boiler 7, a steam generator set, an absorption refrigerator 14, a cooling and LNG preparation device 31, an LNG storage container 32, a dry ice storage container 33, a cold storage device 24, a biogas burner 25, a cold user 27, a heat user 28, a steam process line 29, a high-temperature phase change heat storage container 61, and a low-temperature heat storage container 62 are disposed in a set range (e.g., in a biogas fermentation production area range);
the biogas outlet of the biogas fermentation equipment 1 is communicated with the inlet of the desulfurization and purification equipment 2, and the outlet of the desulfurization and purification equipment 2 is connected with the inlet of the biogas storage container 3 through a biogas valve I41; an outlet of the biogas storage container 3 is communicated with the cooling and preparing LNG facility 31 through a biogas valve eight 34, the cooling and preparing LNG facility 31 is communicated with the LNG storage container 32 and a dry ice storage container 33 respectively, the LNG storage container 32 is used for delivering LNG to an LNG user or an LNG transportation storage facility 35, and the dry ice storage container 33 is used for delivering dry ice to a dry ice user or a dry ice transportation storage facility 36.
The outlet of the desulfurization and purification equipment 2 is also communicated with a biological natural gas combustor 25 through a biological natural gas valve IV 44, and the biological natural gas combustor 25 is used for combusting biological natural gas as fuel so as to supply heat for the biological natural gas boiler 4; and the outlet of the biogas storage container 3 is respectively communicated with the biogas generator set I and the biogas generator set II and is used for supplying biogas required by power generation for the biogas generator set I and the biogas generator set II according to power consumption requirements.
Specifically, in this embodiment, the biogas storage container 3 is communicated with a main line, the main line is respectively communicated with a first branch and a second branch, the first branch and the second branch are respectively communicated with the first biogas gas generator set and the second biogas gas generator set, a third biogas valve 43 is arranged on the main line, a fifth biogas valve 45 is arranged on the first branch, a sixth biogas valve 46 is arranged on the second branch, and the fifth biogas valve 45 and the sixth biogas valve 46 are respectively communicated with the gas inlets of the first biogas gas generator set and the second biogas gas generator set; the outlet of the desulfurization and purification equipment 2 is also respectively communicated with a fifth biological natural gas valve 45 and a sixth biological natural gas valve 46 through a second biological natural gas valve 42.
The biogas boiler 4, the biogas gas generator set I and the biogas gas generator set II are connected to the waste heat boiler 7 and used for conveying exhausted flue gas to the waste heat boiler 7 to supply the waste heat boiler 7 to heat by utilizing heat in the flue gas.
The biological natural gas boiler 4 and the waste heat boiler 7 are both communicated with the high-temperature phase-change heat storage container 61, the steam utilization process line 29, the steam generator set, the low-temperature heat storage container 62, the heat utilization user 28 and the absorption refrigerator 14, and are used for conveying steam to the high-temperature phase-change heat storage container 61, the steam utilization process line 29, the steam generator set, the low-temperature heat storage container 62, the heat utilization user 28 and the absorption refrigerator 14 according to steam utilization or power utilization requirements; the absorption refrigerator 14 is used for supplying cold to a cold user 27 or storing cold by using the cold storage device 24.
Specifically, in this embodiment, a steam outlet of the biogas boiler 4 is sequentially communicated with a first steam valve 51 and a second steam valve 52, and an outlet of the second steam valve 52 is communicated with the steam utilization process line 29; an outlet of the first steam valve 51 is respectively communicated with the high-temperature phase change heat storage container 61 and a fourth steam valve 54, and an outlet of the fourth steam valve 54 is communicated with a steam inlet of the steam generator set; the steam extraction outlet of the steam generator set is communicated with the steam utilization process line 29 through a steam extraction valve 58 and is used for conveying steam extracted from the steam generator set to the steam utilization process line 29; a steam outlet of the waste heat boiler 7 is respectively communicated with a steam valve III 53 and a steam valve V55, the steam valve V55 is communicated with the heat user 28 and the low-temperature heat storage container 62, and the steam valve III 53 is respectively communicated with the high-temperature phase change heat storage container 61, a steam valve IV 54 and a steam valve II 52; the exhaust steam outlet of the steam generator set is communicated with the absorption refrigerator 14 through a first exhaust steam hot valve 56, and is communicated with the heat user 28 and the low-temperature heat storage container 62 through a second exhaust steam hot valve 57, the second exhaust steam hot valve 57 is also communicated with a fifth steam valve 55 and the first exhaust steam hot valve 56 respectively, and the second exhaust steam hot valve 57 is a two-way valve.
In this embodiment, the system further includes a flue gas purification device 8, and the flue gas outlets of the biogas boiler 4 and the exhaust-heat boiler 7 are both communicated with the flue gas purification device 8.
In this embodiment, the biogas gas generator set comprises a biogas engine one 5 and a generator one 21, wherein the biogas engine one 5 is connected to the generator one 21 and provides power for the generator one 21; a fuel gas inlet of the biogas engine I5 is respectively communicated with outlets of the desulfurization and purification equipment 2 and the biogas storage container 3, and is used for obtaining biogas from the desulfurization and purification equipment 2 and/or the biogas storage container 3 according to gas use requirements; and a smoke outlet of the biogas engine I5 is connected to the waste heat boiler 7 and used for conveying the exhausted smoke to the waste heat boiler 7 so that the waste heat boiler 7 can utilize heat in the smoke for heating.
In this embodiment, the biogas fuel gas generator set II comprises a biogas engine II 6 and a generator II 22, and the biogas engine II 6 is connected to the generator II 22 and provides power for the generator II 22; a fuel gas inlet of the second biogas engine 6 is respectively communicated with outlets of the desulfurization and purification equipment 2 and the biogas storage container 3, and is used for obtaining biogas from the desulfurization and purification equipment 2 and/or the biogas storage container 3 according to gas use requirements; and a smoke outlet of the second biogas engine 6 is connected to the waste heat boiler 7 and used for conveying the discharged smoke to the waste heat boiler 7 so that the waste heat boiler 7 can utilize heat in the smoke for heating.
In this embodiment, the steam generator set includes a steam turbine 11 and a third generator 23, the steam turbine 11 is connected to the third generator 23 and provides power for the third generator 23, and a steam inlet of the steam turbine 11 is communicated with the biogas boiler 4 and the waste heat boiler 7, and is used for obtaining high-temperature steam from the biogas boiler 4 and/or the waste heat boiler 7 according to power demand.
In this embodiment, the flue gas outlet of the biogas boiler 4 is further communicated with the exhaust-heat boiler 7, and is used for conveying the discharged flue gas to the exhaust-heat boiler 7, so that the exhaust-heat boiler 7 can heat the flue gas by using the heat in the flue gas.
Example 2
This example provides a method using the biogas multi-mode energy supply system of example 1, which uses different control methods to achieve the digestion of energy such as steam and electricity within a set range (e.g. a fermentation production area range) according to the biogas production and the usage of the user side. The specific process is as follows:
the biogas fermentation equipment 1 produces biogas, and the produced biogas is desulfurized and purified by the desulfurization and purification equipment 2;
when the biogas output of the biogas fermentation equipment 1 is small and the steam process line 29 has a large demand, the biogas valve I41, the biogas valve II 34, the biogas valve III 43 and the biogas valve II 42 are closed, the biogas valve IV 44 is opened, the biogas enters the biogas burner 25 from the desulfurization and purification equipment 2 through the biogas valve IV 44, the biogas burner 25 burns to generate heat to supply heat to the biogas boiler 4, and the biogas boiler 4 generates steam;
the first steam valve 51, the second steam valve 52 and the third steam valve 53 are opened, the fourth steam valve 54, the fifth steam valve 55, the steam extraction valve 58, the first exhaust steam hot valve 56 and the second exhaust steam hot valve 57 are closed, the high-temperature phase change heat storage container 61 is closed, steam generated from the biogas boiler 4 sequentially passes through the first steam valve 51 and the second steam valve 52 and then enters the steam utilization process line 29 to supply steam, and meanwhile, flue gas generated from the biogas boiler 4 enters the waste heat boiler 7 to supply heat to the waste heat boiler 7; the waste heat boiler 7 utilizes the heat of the flue gas to heat the generated steam, and the steam enters the steam utilization process line 29 through a third steam valve 53 and a second steam valve 52 to supply steam; the rest cold and heat requirements and the power requirements in the set range are provided by external input of a power grid, and the flue gas generated in the process is uniformly treated by the flue gas purification equipment 8 and then is discharged into the air, wherein the flue gas is clean and meets the standard.
When the biogas output of the biogas fermentation equipment 1 is small and no demand is required by the steam process line 29, the biogas valve I41, the biogas valve II 34, the biogas valve III 43 and the biogas valve IV 44 are closed, the biogas valve II 42 and the biogas valve V45 are opened, the biogas enters the biogas gas generator set I from the desulfurization and purification equipment 2 through the biogas valve II 42 and the biogas valve V45 in sequence, and the biogas gas generator set I generates power by burning the biogas (specifically, the biogas engine I5 burns the biogas to obtain power and then drives the generator set I21 to generate power). And a fifth steam valve 55, a second steam exhaust hot valve 57 and a first steam exhaust hot valve 56 are opened, and a third steam valve 53 is closed. The electricity generated by the biogas gas generator set supplies electricity within the set range; meanwhile, flue gas generated from the first biogas-gas generator set is conveyed to the waste heat boiler 7, the waste heat boiler 7 is heated by using the heat of the flue gas to generate steam, part of the steam is supplied to a hot user 28 through a fifth steam valve 55, part of the steam enters the absorption refrigerator 14 through a second exhaust steam hot valve 57 and a first exhaust steam hot valve 56 in sequence, the absorption refrigerator 14 generates cold energy by using the steam heat to be used by a cold user 27, and if redundant steam exists, heat is stored through a low-temperature heat storage container 62 according to the user requirement, and/or cold is stored for later use by using a cold storage device 24 after being refrigerated by the absorption refrigerator 14; on the basis, if the steam utilization process line 29 has a small demand, the third steam valve 53 and the second steam valve 52 are opened, the first steam valve 51, the fourth steam valve 54 and the steam extraction valve 58 are kept closed, and steam is supplied according to the demand of the steam utilization process line 29; the flue gas generated in the process is treated by the flue gas purification equipment 8 uniformly and then the clean flue gas meeting the standard is discharged into the air.
When the biogas output of the biogas fermentation equipment 1 is large and the steam process line 29 does not need, the biogas valve II 42 and the biogas valve IV 44 are closed, the biogas valve I41, the biogas valve III 34, the biogas valve V45 and the biogas valve VI 46 are opened, the biogas firstly enters the biogas storage container 3 for storage, then passes through the biogas valve III 43 according to the demand and then respectively enters the biogas gas generator set I and the biogas gas generator set II through the biogas valve V45 and the biogas valve VI 46, the biogas gas generator set I and the biogas gas generator set II respectively obtain power through burning the biogas to generate electricity (the biogas engine I5 and the biogas engine II 6 respectively obtain power through burning the biogas and respectively drive the generator I21 and the generator II 22 to generate electricity Power generation). Flue gas generated in the biogas gas generator set I and the biogas gas generator set II is sent to the waste heat boiler 7, the waste heat boiler 7 is heated by using heat in the flue gas to generate steam, the generated steam enters the steam generator set through the steam valve III 53 and the steam valve IV 54, and the steam generator set generates power by using heat energy of the steam to generate electricity (specifically, the steam turbine 11 generates power by using heat energy of the steam to drive the generator III 23 to generate electricity); part of the exhaust steam in the steam generator set enters the absorption refrigerator 14 through the first exhaust steam hot valve 56, the absorption refrigerator 14 generates cold energy by using the heat of the exhaust steam for being used by a cold user 27, the rest of the exhaust steam is used by a hot user 28 through the second exhaust steam hot valve 27, and the rest of the exhaust steam is subjected to heat storage through the low-temperature heat storage container 62 according to the user requirements and/or is subjected to cold storage for later use by using the cold storage device 24 after being refrigerated by the absorption refrigerator 14. The generated surplus power starts the cooling LNG preparation equipment 31, the biogas enters the cooling LNG preparation equipment 31 from the biogas storage container 3 through the biogas valve eight 34 and is cooled, dry ice is firstly separated out in the early stage of the cooling process and is separated and stored in the dry ice storage container 33, and liquid LNG obtained after continuous cooling is stored in the LNG storage container 32. After reaching a certain storage capacity, the dry ice and the liquid LNG can be used by a dry ice user 36 and an LNG user 35 respectively. And the flow of the biogas passing through the third biogas valve 43 and the eighth biogas valve 34 is subjected to flow division control according to the power consumption of unit LNG production, so that the generated power can be consumed within the set range. On the basis of the above, when a small amount of demand is made in the steam using process line 29, the steam extraction valve 58 is opened, and the steam is extracted from the steam generator set according to the demand of the steam using process line 29 and supplied to the steam using process line 29. The flue gas is treated by the flue gas purification equipment 8 uniformly and then the clean flue gas meeting the standard is discharged into the air.
When the biogas output of the biogas fermentation equipment 1 is large and the demand of the steam process line 29 is large, the biogas valve II 42 is closed, the biogas valve I41, the biogas valve III 43, the biogas valve IV 44, the biogas valve V45, the biogas valve VI 46 and the biogas valve VIII 34 are opened, a part of the biogas desulfurized and purified by the desulfurization and purification equipment 2 enters the biogas burner 25 through the biogas valve IV 44 to be combusted, the heat generated by combustion supplies heat to the biogas boiler 4, and steam is generated in the biogas boiler 4; one part of the power enters a first biogas fuel generator set and a second biogas fuel generator set through a fifth biogas valve 45 and a sixth biogas valve 46 to obtain power for power generation; one part of the biogas passes through a biogas valve I41 and is stored in a biogas storage container 3; the first steam valve 51, the third steam valve 53, the fourth steam valve 54, the steam extraction valve 58, the second exhaust steam hot valve 57 and the first exhaust steam hot valve 56 are opened, and the second steam valve 52 and the fifth steam valve 55 are closed; steam generated in the biogas boiler 4 enters the steam generator set through the first steam valve 51 and the fourth steam valve 54, meanwhile, flue gas generated by the biogas boiler 4, the first biogas gas generator set and the second biogas gas generator set enters the waste heat boiler 7 to supply heat to the waste heat boiler, steam generated by the waste heat boiler 7 by utilizing heat of the flue gas enters the steam generator set through the third steam valve 53 and the fourth steam valve 54 in sequence to obtain power for power generation, and surplus steam enters the high-temperature phase-change heat storage container 61 through the third steam valve 53 to exchange heat and store heat energy; extracting steam from the steam generator set through a steam extraction valve 58 for use by the steam processing line 29; part of the exhaust steam generated by the steam generator set enters the absorption refrigerator 14 through the first exhaust steam hot valve 56 to generate cold energy for the cold user 27, the rest of the exhaust steam is supplied to the hot user 28 through the second exhaust steam hot valve 57, and the rest of the exhaust steam is subjected to heat storage through the low-temperature heat storage container 62 according to the user requirements and/or is refrigerated through the absorption refrigerator 14 and then is subjected to cold storage for later use through the cold storage device 24. The generated surplus electric power starts the cooling LNG preparation equipment, the biogas enters the cooling LNG preparation equipment 31 from the biogas storage container 3 through the biogas valve eight 34 and is cooled, dry ice is firstly separated out in the early stage of the cooling process and is separated and stored in the dry ice storage container 33, and liquid LNG obtained after continuous cooling is stored in the LNG storage container 32. After reaching a certain storage capacity, the dry ice and the liquid LNG are supplied to a dry ice user 36 and an LNG user 35 for use. And the flow of the biogas passing through the third natural gas valve 43 and the eighth natural gas valve 34 is subjected to flow splitting control according to the power consumption of unit LNG preparation, so that the generated power can be consumed in the set range. On the basis, when the demand of the steam using process line 29 is further increased, the steam extraction valve 58 and the steam valve four 54 are closed, the steam valve two 52 is opened, and the steam generated from the waste heat boiler 7 and the biogas boiler 4 directly enters the steam using process line 29 to meet the steam using demand. The flue gas is treated by the flue gas purification equipment 8 uniformly and then the clean flue gas meeting the standard is discharged into the air.
After the energy storage load in the high-temperature phase-change heat storage container 61 reaches the full load, the LNG production rate and the power generation rate are increased, and the combustion gas consumption of the biogas boiler is reduced. When the adjusted steam is insufficient in heat supply, the adjusted steam is supplied by the high-temperature phase change heat storage container 61, so that fluctuation of the power equipment is reduced.
Various corresponding changes and modifications can be made by those skilled in the art according to the above technical solutions and concepts, and all such changes and modifications should be included in the protection scope of the present invention.