An electric-driven heat pump steam production device and method for zero-carbon operation

Abstract

The present invention discloses an electric-driven heat pump steam production device and method with zero-carbon operation. The device includes a medium-deep geothermal buried pipe unit, a primary heat pump unit, a secondary heat pump unit, a local electric heating unit, a heat recovery unit, a photovoltaic power generation unit, and a building user unit. Based on the medium-deep geothermal buried pipe, the present invention extracts medium-deep geothermal energy at 70-90°C underground through the way of wall-to-wall heat exchange, realizing the stable, continuous, and efficient utilization of this high-grade renewable energy of medium-deep geothermal energy. At the same time, combined with a large amount of recoverable waste heat after steam use, it greatly replaces the traditional fossil energy consumed in the original steam production process. Secondly, by centrally producing 120°C steam through an electric-driven heat pump and then slightly increasing the temperature by local electric heating, the full electrification of the steam production process is realized. Equipped with a photovoltaic power generation system, it generates zero-carbon clean electricity to drive the efficient operation of the entire system, realizing the zero-carbon operation of industrial steam production.

Description

Technical Field

[0001] The present invention relates to a heat pump steam production device and method, and particularly to an electrically driven heat pump steam production device and method with zero-carbon operation. Background Art

[0002] China is a major industrial production country, and carbon emissions brought about by energy consumption in the industrial field are an important part of China's total carbon emission structure. Industrial steam is an important energy consumption in the industrial field. At present, among the heat source forms for industrial steam production in China, traditional fossil fuels, including coal and gas, still dominate. Traditional fossil fuels convert internal energy into heat energy for heating through combustion, and CO2 generated during the combustion process is one of the main greenhouse gases causing global warming. Therefore, in order to achieve carbon peak before 2030 and carbon neutrality before 2060, the sustainable low-carbon development of the industrial field, especially how to achieve zero-carbon operation of steam production, becomes crucial.

[0003] If a direct electric steam generator is used to produce steam, on the one hand, it will bring relatively high operating costs, and at the same time, direct heating with high-quality electricity will also bring relatively large indirect carbon emissions, which is contrary to the goal of sustainable low-carbon development in the industrial field. Therefore, how to make full use of renewable energy, including medium-deep geothermal energy that can provide high-quality heat and solar energy that can provide clean electricity, has become the key to achieving decarbonization or even zero-carbon of industrial steam production. Summary of the Invention

[0004] In order to solve the deficiencies of the above-mentioned technologies, the present invention provides an electrically driven heat pump steam production device and method with zero-carbon operation.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: an electrically driven heat pump steam production device with zero-carbon operation, including a medium-deep geothermal buried pipe unit, a primary heat pump unit, a secondary heat pump unit, a local electric heating unit, a heat recovery unit, a photovoltaic power generation unit, and a building user unit;

[0006] The medium-deep geothermal buried pipe unit is connected to the geothermal energy distribution unit, and the geothermal energy distribution unit is connected to the primary heat pump unit; the primary heat pump unit is connected to the hot water distribution unit, the hot water distribution unit is connected to the secondary heat pump unit, the secondary heat pump unit is connected to the steam distribution unit, and the steam distribution unit is connected to the local electric heating unit; the local electric heating unit is connected to the building user unit, the building user unit is connected to the heat recovery unit, the heat recovery unit is connected to the secondary heat pump unit, and the photovoltaic power generation unit is connected to the primary heat pump unit, the secondary heat pump unit, the hot water distribution unit, the geothermal energy distribution unit, the steam distribution unit, and the local electric heating unit.

[0007] Furthermore, the medium-deep geothermal buried pipe unit contains one or more medium-deep geothermal buried pipes, each of which has a depth of 2-3 kilometers. The medium-deep geothermal buried pipe extracts 70-90℃ medium-deep geothermal energy underground by interlayer heat exchange without exploiting groundwater.

[0008] Furthermore, the geothermal energy transmission and distribution unit contains one or more variable frequency water pumps, and the water pump frequency is adjustable from 25Hz to 50Hz; the heat recovery unit contains a steam condensation waste heat recovery device.

[0009] Furthermore, the first-level heat pump unit contains one or more magnetic levitation high-efficiency heat pump units; the second-level heat pump unit contains one or more magnetic levitation high-efficiency heat pump units; the first-level heat pump unit and the second-level heat pump unit operate in series to achieve step-by-step heating; the steam distribution unit contains one or more steam booster pumps for distributing centrally produced steam to various energy-consuming terminals; the local electric heating unit contains one or more distributed steam electric heating systems.

[0010] Furthermore, the photovoltaic power generation unit contains photovoltaic panels to provide clean electricity for the operation of the entire system.

[0011] Furthermore, the intelligent control unit contains an intelligent control system based on big data analysis; after the steam system is electrified, on the one hand, it is necessary to absorb the power generated by the photovoltaic system, and at the same time, use municipal electricity to drive it when the photovoltaic power generation is insufficient. Therefore, an intelligent control system is used to achieve efficient operation and control of the entire system.

[0012] A working method of a zero-carbon electric-driven heat pump steam production device is as follows:

[0013] The geothermal energy transmission and distribution unit drives the heat source water to extract heat from the soil through the medium-deep geothermal buried pipe unit. The heat source water extracts the medium-deep geothermal energy and enters the primary heat pump unit; the primary heat pump unit absorbs heat from the heat source water, raises the temperature through a compressor to produce hot water, and the produced hot water is mixed with the steam condensed waste water recovered by the heat recovery unit and then transported to the secondary heat pump unit; the secondary heat pump unit absorbs heat from the hot water, raises the temperature through a compressor to produce steam, and the produced steam is transported to the building user unit for use through the steam transmission and distribution unit;

[0014] In areas where higher temperature and pressure steam is required, local electric heating units are used for heating; the steam used by the building user unit is recovered by the heat recovery unit to condense waste hot water; the solar photovoltaic power generation of the photovoltaic power generation unit covers the power consumption of the entire system, drives the operation of the entire system, and realizes zero carbon electricity consumption.

[0015] A design method for an electric-driven heat pump steam production device with zero-carbon operation is as follows: According to the process requirements of the project, determine the steam consumption requirements at different temperatures, and combine the potential of recoverable steam waste heat to determine the heat that needs to be supplemented by renewable geothermal energy; Determine the cumulative heat extraction of a single medium-deep geothermal buried pipe according to the geological geothermal conditions at the project location, and determine the number of medium-deep geothermal buried pipes that need to be exploited; Select an electric heating system for local steam temperature increase according to the special steam requirements of the local area; After determining the system form, according to the annual steam consumption requirements, clarify the annual cumulative power consumption requirements, and combine the annual solar radiation intensity to calculate the photovoltaic panel laying area with all the electricity demand provided by the photovoltaic power generation unit.

[0016] Furthermore, the design method for the electric-driven heat pump steam production device with zero-carbon operation specifically includes the following steps:

[0017] Step 1: According to the process requirements of the project, determine the hourly steam consumption requirements and the annual cumulative consumption requirements at different temperatures, and clarify the heat Q required for steam production h，a , including the heat Q h，a，1 for raising the hot water from 40°C to 60°C, the heat Q h，a，2 for raising the 60°C hot water to 0.2 MPa steam, and the heat Q h，a，3 for further increasing the temperature and pressure locally;

[0018] Step 2: Combine the process requirements of the project to evaluate the potential of recoverable waste heat after steam use, so as to obtain the annual cumulative recoverable waste heat Q r，a , clarify the heat Q g that needs to be supplemented from renewable geothermal energy, and the calculation formula is as shown in Formula 1-2;

[0019] Q h，a，1 =Q h，a -Q h，a，2 -Q h，a，3 -Q r，a Formula 1

[0020]

[0021] Among them, Q h，a，1 is the heat for raising the hot water from 40°C to 60°C, in GJ; Q h，a，2 is the heat for raising the 60°C hot water to 0.2 MPa steam, in GJ; Q h，a，3 is the heat for further increasing the temperature and pressure locally, in GJ; Q r，a is the annual cumulative recoverable waste heat, in GJ; Q g is the heat that needs to be supplemented from renewable geothermal energy, in GJ; COP1 is the heating efficiency of the first-stage heat pump system, which can be taken as 4.5;

[0022] Step 3: Define the geothermal geological conditions at the project location, including soil thermal conductivity and temperature rise gradient, and select appropriate buried pipe sizes and construction processes based on the geological conditions;

[0023] Step 4: Combine the geothermal geological conditions, calculate the recommended value of the cumulative heat extraction of a single medium-deep geothermal buried pipe based on an annual average soil temperature drop of no more than 0.2 °C, and then calculate the number of medium-deep geothermal buried pipes to be exploited according to the total heat that needs to be supplemented from renewable geothermal energy throughout the year. The calculation formula is as shown in Formula 3-4;

[0024] Q a = F g ·q c ·Δτ + F g ·H·ρ·C t ·ΔT Formula 3

[0025]

[0026] Where, Q a is the recommended value of the annual cumulative heat extraction of the medium-deep geothermal buried pipe, in GJ; F g is the cross-sectional area of the soil control volume, in m 2 ; q c is the local geothermal heat flux density, in W / m 2 ; Δτ is the time of one year, in s; H is the depth of the medium-deep geothermal buried pipe, in m; ρ is the soil density, in kg / m 3 ; C t is the specific heat capacity of the soil, in kJ / (kg·°C); ΔT is the annual temperature change of the soil control volume. Q g is the heat that needs to be supplemented from renewable geothermal energy, in GJ; N is the number of exploited medium-deep geothermal buried pipes;

[0027] Step 5: With a designed circulation flow rate of 30 m 3 / h and a designed circulation resistance of 50 mH2O for a single medium-deep geothermal buried pipe, determine the installed capacity of the heat source side water pump according to the number of medium-deep geothermal buried pipes to be exploited;

[0028] Step 6: Determine the installed capacity of the heat supply of the heat pump unit for centrally producing 120 °C steam and the installed capacity of the distribution system for centrally transporting and distributing steam according to the steam supply demand of the project;

[0029] Step 7: For a locally higher steam usage demand Q h，a，3 , determine the installed capacity W eb of the electric heating device to be locally installed;

[0030] Step 8. After determining the system form, based on the annual steam demand of the project and the system operation energy efficiency, determine the annual cumulative power consumption, and the calculation formula is as shown in Formula 5;

[0031]

[0032] Among them, W is the annual power consumption of the system, with the unit of kWh; η is the electric heating efficiency; COP1 is the heating energy efficiency of the first-stage heat pump system, taken as 4.5; COP2 is the heating energy efficiency of the second-stage heat pump system, taken as 3.0;

[0033] Step 9. Subsequently, in combination with the annual solar radiation intensity, use the photovoltaic power generation unit to provide all the electricity demand of the modular system, calculate the laying area of the photovoltaic panels, and then obtain the hourly power generation of the photovoltaic throughout the year.

[0034] The present invention discloses an electric-driven heat pump steam production device and method with zero-carbon operation. Based on the medium-deep geothermal buried pipe, the medium-deep geothermal energy at 70-90°C underground is extracted through the way of wall heat exchange, realizing the stable, continuous and efficient utilization of the high-grade renewable energy of medium-deep geothermal energy. At the same time, combined with a large amount of recoverable waste heat after steam use, it greatly replaces the traditional fossil energy consumed in the original steam production process; secondly, by using an electric-driven heat pump to centrally produce 120°C steam and then slightly increase the temperature by local electric heating, the full electrification of the steam production process is realized. Equipped with a photovoltaic power generation system, it generates zero-carbon clean electricity to drive the entire system to operate efficiently, realizing the zero-carbon operation of industrial steam production. Brief Description of the Drawings

[0035] Figure 1 It is a schematic diagram of the electric-driven heat pump steam production device with zero-carbon operation of the present invention.

[0036] Figure 2 It is a schematic diagram of the design method of the electric-driven heat pump steam production device with zero-carbon operation of the present invention.

[0037] In the figure: 1. Medium-deep geothermal buried pipe unit; 2. First-stage heat pump unit; 3. Second-stage heat pump unit; 4. Local electric heating unit; 5. Heat recovery unit; 6. Photovoltaic power generation unit; 7. Building user unit. Detailed Embodiments

[0038] The present invention will be further described in detail below in conjunction with the drawings and specific embodiments.

[0039] As Figure 1As shown in the figure, an electric-driven heat pump steam production device with zero-carbon operation includes a medium-deep geothermal buried pipe unit 1, a primary heat pump unit 2, a secondary heat pump unit 3, a local electric heating unit 4, a heat recovery unit 5, a photovoltaic power generation unit 6, a building user unit 7, and an intelligent control unit; the building user unit 7 is the actual heating terminal.

[0040] The medium-deep geothermal buried pipe unit 1 is connected to the primary heat pump unit 2 through a geothermal energy distribution unit; the primary heat pump unit 2 is connected to the secondary heat pump unit 3 through a hot water distribution unit; the secondary heat pump unit 3 is connected to the local electric heating unit 4 through a steam distribution unit; the local electric heating unit 4 is connected to the building user unit 7, and the building user unit 7 is connected to the secondary heat pump unit through the heat recovery unit 5; the photovoltaic power generation unit 6 is connected to the primary heat pump unit 2, the secondary heat pump unit 3, the hot water distribution unit, the geothermal energy distribution unit, the steam distribution unit, and the local electric heating unit 4, and the intelligent control unit is connected to each energy-using system.

[0041] The medium-deep geothermal buried pipe unit 1 contains one or more medium-deep geothermal buried pipes, and the depth of each medium-deep geothermal buried pipe is 2 - 3 kilometers. On the basis of not mining groundwater, the medium-deep geothermal buried pipes extract medium-deep geothermal energy at 70 - 90 °C underground through the way of wall-to-wall heat exchange. If operating continuously, the peak heat extraction of one medium-deep geothermal buried pipe can reach 500 kW, and the outlet water temperature can reach 30 °C. If an intermittent operation mode (operating for 10 hours and stopping for 14 hours) is adopted, the peak heat extraction of one medium-deep geothermal buried pipe can reach 700 kW, and the outlet water temperature can reach 40 °C.

[0042] Since the temperature of the medium-deep geothermal energy is relatively high, it is only suitable for heat extraction and heating in winter, and heat cannot be discharged into it in summer. Considering the recovery requirement of the soil temperature for long-term operation, the recommended cumulative heat extraction of one medium-deep geothermal buried pipe is different under different geothermal geological conditions, which is also the key content to be considered in the design method.

[0043] The geothermal energy distribution unit contains one or more variable-frequency water pumps, and the pump frequency can be adjusted from 25 Hz to 50 Hz; the heat recovery unit 5 contains a steam condensation waste heat recovery device; after industrial steam is used, there must be a large amount of condensation waste heat with a temperature of 60 - 80 °C. For the recovery and utilization of this part of heat, compared with directly heating tap water (10 - 20 °C), a large proportion of energy savings will be achieved. Therefore, the recovery of steam condensation waste heat will be a key core of the present invention.

[0044] The heat pump unit is composed of two - stage heat pump units connected in series. The first - stage heat pump unit 2 contains one or more customized magnetic - levitation high - efficiency heat pump units. This heat pump unit makes full use of the characteristic that the magnetic - levitation variable - frequency compressor does not require lubricating oil, can better adapt to the operation under high - temperature conditions, extract heat from medium - deep geothermal energy at 40°C or higher, produce high - temperature water at 60°C, and the heating efficiency of the first - stage heat pump system will reach 6.0.

[0045] The second - stage heat pump unit 3 contains one or more customized magnetic - levitation high - efficiency heat pump units. This heat pump unit makes full use of the characteristic that the magnetic - levitation variable - frequency compressor does not require lubricating oil, can better adapt to the operation under high - temperature and large pressure - ratio conditions, extract heat from the 60°C high - temperature water, through the large pressure - ratio operation of the magnetic - levitation heat pump, and pass through a special condenser to directly generate steam at 110 - 120°C. The heating efficiency of the second - stage heat pump system will reach 3.0, greatly reducing the electric energy consumed for steam production and achieving obvious energy - saving and emission - reduction benefits.

[0046] The first - stage heat pump unit 2 and the second - stage heat pump unit 3 operate in series to achieve step - by - step temperature rise. This heat pump unit makes full use of the characteristic that the magnetic - levitation variable - frequency compressor does not require lubricating oil, can better adapt to the operation under high - temperature and large compression - ratio conditions. The first - stage heat pump unit extracts heat from medium - deep geothermal energy, heats it to 60°C, and then after mixing with the waste heat of steam condensation, it is reheated by the second - stage heat pump unit. Through the large pressure - ratio operation of the magnetic - levitation heat pump and passing through a special condenser, it will directly generate steam at 110 - 120°C.

[0047] The hot - water distribution unit contains one or more variable - frequency water pumps, and the pump frequency is adjustable from 25Hz to 50Hz.

[0048] The steam distribution unit contains one or more steam booster pumps for distributing the centrally - produced steam to each energy - using end; the local electric - heating unit contains one or more distributed steam electric - heating systems. Since different steam - using ends have different requirements for steam temperature and pressure, for the 120°C steam produced centrally, after being transported to the end, local electric heating is carried out according to the actual steam demand.

[0049] The photovoltaic power - generation unit 6 contains photovoltaic panels to provide clean electricity for the operation of the entire device.

[0050] The intelligent control unit contains an intelligent control system based on big - data analysis. After the steam system is electrified, on the one hand, it needs to absorb the power generation of the photovoltaic system, and at the same time, it uses municipal power to drive when the photovoltaic power generation is insufficient. Therefore, an intelligent control system is used to achieve the efficient operation control of the entire device.

[0051] Compared with conventional heating technologies, the medium-deep geothermal ground-source heat pump heating technology has the advantages of high heat source temperature, large heat extraction capacity, stable system operation, high performance, small floor area, and protection of underground water resources. It is not affected by ground climate conditions and can achieve clean, efficient, and sustainable utilization of medium-deep geothermal energy. It is a more excellent renewable energy clean and efficient heating technology. In heating applications, the proportion of renewable energy is as high as over 80%, realizing heating electrification. The carbon dioxide emission per unit of heat supply is only 30 - 40 kg / GJ, and with the drive of clean electricity, the goal of zero-carbon heating can be achieved.

[0052] Where there is steam usage, there must be waste heat recovery. For the condensate waste heat after steam usage, a heat recovery device is used for full recovery to obtain recovered hot water at 60 - 80°C, which, together with the medium-deep geothermal ground-source heat supply water, provides high-temperature heat source water for the heat pump unit. On the one hand, it increases the evaporation temperature, thereby improving the efficiency of the heat pump unit in producing steam and reducing power consumption. On the other hand, compared with directly heating tap water (10 - 20°C), it will achieve a large proportion of energy savings and have obvious energy conservation and emission reduction benefits.

[0053] Photovoltaic power generation technology fully utilizes solar radiation to generate renewable clean electricity, which is used to drive the heat pump system to heat the building user unit (terminal), achieving the goal of zero-carbon heating.

[0054] A working method of an electric-driven heat pump steam production device with zero-carbon operation is as follows:

[0055] The geothermal energy distribution unit drives the heat source water to extract heat from the soil via the medium-deep geothermal ground-source unit 1. After the heat source water extracts medium-deep geothermal energy, it enters the primary heat pump unit 2; the primary heat pump unit 2 absorbs heat from the heat source water and raises the temperature to produce hot water through a compressor. The produced hot water is mixed with the steam condensate recovered by the heat recovery unit 5 and then transported to the secondary heat pump unit 3; the secondary heat pump unit 3 absorbs heat from the hot water and raises the temperature to produce steam through a compressor. The produced steam is transported to the building user unit 7 for use via the steam distribution unit;

[0056] In areas where steam with higher temperature and pressure is locally required, a local electric heating unit 4 is used for heating; the steam used by the building user unit 7 is recovered as steam condensate by the heat recovery unit 5; the solar photovoltaic power generation of the photovoltaic power generation unit 6 bears the power consumption of the entire system and drives the operation of the entire system to achieve zero-carbon electricity use.

[0057] For the zero-carbon operation electric-driven heat pump steam production device disclosed in the present invention, a specific configuration design of the device is carried out. According to the process requirements of the project, the steam consumption requirements at different temperatures are determined, and combined with the potential of recoverable steam waste heat, the heat that needs to be supplemented by renewable geothermal energy is determined; according to the geological geothermal conditions of the project location, the cumulative heat extraction amount of a single medium-deep geothermal buried pipe is determined, and the number of medium-deep geothermal buried pipes that need to be exploited is determined; according to the special steam requirements of the local area, an electric heating system is selected to locally increase the temperature of the steam; after determining the system form, according to the annual steam consumption requirements, the annual cumulative power consumption requirements are clarified, and combined with the annual solar radiation intensity, all the power consumption requirements are provided by the photovoltaic power generation unit, and the laying area of the photovoltaic panels is calculated.

[0058] As Figure 2 shown, the design method of the zero-carbon operation electric-driven heat pump steam production device specifically includes the following steps:

[0059] Step 1: According to the process requirements of the project, determine the hourly steam consumption requirements and the annual cumulative consumption requirements at different temperatures, and clarify the heat Q h，a consumed for producing steam, including the heat Q h，a，1 required to raise the hot water from 40°C to 60°C, the heat Q h，a，2 required to raise the hot water from 60°C to 0.2 MPa steam, and the heat Q ha，3 required to further increase the temperature and pressure locally; the parameters determined in this step are the input conditions for the device configuration, and their calculation and analysis are all prior arts;

[0060] Step 2: Combine the process requirements of the project to evaluate the potential of recoverable waste heat after steam use, so as to obtain the annual cumulative recoverable waste heat Q r，a and clarify the heat Q g that needs to be supplemented from renewable geothermal energy. The calculation formula is as shown in Formula 1-2;

[0061] Q h，a，1 =Q h，a -Q h，a，2 -Q h，a，3 -Q r，a Formula 1

[0062]

[0063] Among them, Q h，a，1 is the heat required to raise the hot water from 40°C to 60°C, in GJ; Q h，a，2 is the heat required to raise the hot water from 60°C to 0.2 MPa steam, in GJ; Q h，a，3 is the heat required to further increase the temperature and pressure locally, in GJ; Q r，a is the annual cumulative recoverable waste heat, in GJ; Q gThe heat to be supplemented from renewable geothermal energy, in GJ; COP1 is the heating energy efficiency of the first-stage heat pump system, which can be taken as 4.5;

[0064] Step 3: Define the geothermal geological conditions at the project location, including the soil thermal conductivity and temperature rise gradient, and select appropriate buried pipe sizes and construction processes according to the geological conditions;

[0065] Step 4: Combine the geothermal geological conditions, calculate the recommended value of the cumulative heat extraction of a single medium-deep geothermal buried pipe according to the annual average soil temperature drop not exceeding 0.2 °C, and then calculate the number of medium-deep geothermal buried pipes to be exploited based on the total heat to be supplemented from renewable geothermal energy throughout the year. The calculation formula is shown in Formula 3-4;

[0066] Q a = F g ·q c ·Δτ + F g ·H·ρ·C t ·ΔT Formula 3

[0067]

[0068] Among them, Q a is the recommended value of the annual cumulative heat extraction of the medium-deep geothermal buried pipe, in GJ; F g is the cross-sectional area of the soil control volume, in m 2 ; q c is the local geothermal heat flux density, in W / m 2 ; Δτ is the time of one year, in s; H is the depth of the medium-deep geothermal buried pipe, in m; ρ is the soil density, in kg / m 3 ; C t is the specific heat capacity of the soil, in kJ / (kg·°C); ΔT is the annual temperature change of the soil control volume. Q g is the heat to be supplemented from renewable geothermal energy, in GJ; N is the number of medium-deep geothermal buried pipes to be exploited.

[0069] Step 5: With a designed circulation flow rate of 30 m 3 / h for a single medium-deep geothermal buried pipe and a designed circulation resistance of 50 mH2O, determine the installed capacity of the heat source side water pump according to the number of medium-deep geothermal buried pipes to be exploited;

[0070] Step 6: According to the steam supply demand of the project, determine the installed capacity of the heat pump unit for centralized production of 120 °C steam and the installed capacity of the steam centralized distribution system by using conventional methods in existing technologies;

[0071] Step 7: For local higher steam usage demand Q h，a，3, the heating installed capacity W of the electric heating device to be installed locally is determined by the conventional method in the prior art eb ;

[0072] Step Eight: After clarifying the system form, that is, according to the annual steam demand of the project and the system operation energy efficiency, determine the annual cumulative power consumption, and the calculation formula is as shown in Formula 5;

[0073]

[0074] Among them, W is the annual power consumption of the system, with the unit of kWh; η is the electric heating efficiency; COP1 is the heating energy efficiency of the first-stage heat pump system, taken as 4.5; COP2 is the heating energy efficiency of the second-stage heat pump system, taken as 3.0;

[0075] Step Nine: Subsequently, in combination with the annual solar radiation intensity, use the photovoltaic power generation unit to provide all the electricity demand of the modular system, and calculate the photovoltaic panel laying area by the conventional method in the prior art, and then obtain the hourly power generation of the photovoltaic throughout the year.

[0076] Therefore, compared with the prior art, the zero-carbon operation electric drive heat pump steam production device and method of the present invention have the following advantages:

[0077] 1) The present invention adopts centralized production and distribution of low-temperature (110 - 120 °C) steam, and locally uses electric heating to further increase the temperature and pressure according to process requirements. On the one hand, it avoids the energy waste caused by centralized production of high-temperature steam, and on the other hand, it avoids the heat leakage loss caused by centralized distribution of high-temperature steam;

[0078] 2) The present invention makes full use of the characteristics that the horizontal floor area of the medium-deep geothermal buried pipe is small (the pipe diameter is only 200 - 300 mm) and it can be flexibly arranged for exploitation, and constructs a modular steam supply system. The way of dispersedly exploiting the medium-deep geothermal buried pipe close to the building red line and setting the modular steam supply system nearby, on the one hand, avoids the situation of mutual influence of heat exchange in the centralized exploitation of the medium-deep geothermal buried pipe, and on the other hand, cancels the large-area steam distribution pipe network, avoiding problems such as pipe network heat leakage loss and hydraulic imbalance, and at the same time reducing the transportation energy consumption;

[0079] 3) The present invention realizes the full electrification of steam production, avoiding the direct carbon emissions caused by the combustion of traditional fossil fuels. At the same time, by making full use of medium-deep geothermal energy, steam recovery waste heat, high-efficiency heat pump technology, etc., compared with direct electric heating, the electricity demand is greatly reduced, and the indirect carbon emissions in the steam production process are greatly reduced. Finally, combined with photovoltaic power generation to provide clean electricity, zero-carbon operation of steam production and supply is realized;

[0080] 4) The present invention can be further operated in combination with an intelligent control system for big data analysis; after the electrification of the steam system, on the one hand, it is necessary to absorb the power generation of the photovoltaic system, and on the other hand, municipal power is used to drive when the power generation of photovoltaic power is insufficient. For a single project, predicting the power generation of photovoltaic power based on weather forecasts and combining corresponding energy storage control technologies is the key to achieving zero-carbon steam in industrial projects. When the technology is popularized to a certain scale, the intelligent control system of the cloud platform based on big data analysis will realize the overall scheduling of this technology based on the power generation law of municipal clean power, realize the demand-side response of electricity, and absorb more clean and low-carbon electricity.

[0081] The above embodiments are not limitations on the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by those skilled in the art within the scope of the technical solution of the present invention also fall within the protection scope of the present invention.

Claims

1. A design method for an electric-driven heat pump steam production device with zero-carbon operation, characterized in that: According to the process requirements of the project, determine the steam consumption requirements at different temperatures. Combining the potential of recoverable steam waste heat, determine the heat that needs to be supplemented by renewable geothermal energy. Determine the cumulative heat extraction of a single medium-deep geothermal buried pipe according to the geological geothermal conditions at the project location, and determine the number of medium-deep geothermal buried pipes that need to be exploited. According to the special steam requirements in some areas, select an electric heating system for local steam temperature increase. After determining the system form, according to the annual steam consumption requirements, clarify the annual cumulative power consumption requirements. Combining the annual solar radiation intensity, use a photovoltaic power generation unit to provide all the power demand, and calculate the laying area of the photovoltaic panels. The design method specifically includes the following steps: Step 1: According to the process requirements of the project, determine the hourly consumption requirements and annual cumulative consumption requirements of steam at different temperatures, and clarify the heat Q required for steam production h，a , including the heat Q for raising hot water from 40°C to 60°C h，a，1 , the heat Q for raising hot water from 60°C to 0.2 MPa steam h，a，2 , and the heat Q for locally continuing to increase the temperature and pressure h，a，3 ; Step 2: Combine the process requirements of the project to evaluate the potential of recoverable waste heat after steam use, so as to obtain the annual cumulative recoverable waste heat quantity Q r，a , and clarify the heat quantity Q g that needs to be supplemented from renewable geothermal energy. The calculation formula is as shown in Formula 1-2; Q h，a,1 = Q h,a -Q h,a,2 -Q h，a,3 -Q r,a , Formula 1 Among them, Q h，a，1 is the heat required to raise the temperature of hot water from 40°C to 60°C, with the unit of GJ; Q h，a，2 is the heat required to raise the temperature of hot water from 60°C to steam at 0.2 MPa, with the unit of GJ; Q h，a，3 is the heat required to locally continue to increase the temperature and pressure, with the unit of GJ; Q r,a is the annual cumulative recoverable surplus heat, with the unit of GJ; Q g is the heat that needs to be supplemented from renewable geothermal energy, with the unit of GJ; COP1 is the heating energy efficiency of the first-stage heat pump system, which can be taken as 4.5; Step 3: Clarify the geothermal geological conditions at the project location, including the soil thermal conductivity and temperature rise gradient, and select appropriate buried pipe sizes and construction processes according to the geological conditions. Step 4: Combining the geothermal geological conditions, calculate the recommended value of the cumulative heat extraction of a single medium-deep geothermal buried pipe according to the annual average soil temperature drop not exceeding 0.2 °C. Then, calculate the number of medium-deep geothermal buried pipes that need to be exploited according to the total heat that needs to be supplemented from renewable geothermal energy throughout the year. The calculation formula is shown in Formula 3-4. Q a = F g ·q c ·Δτ + F g ·H·ρ·C t ·ΔT, Formula 3 Among them, Q a is the recommended annual cumulative heat extraction value of the medium-deep geothermal buried pipe, in GJ; F g is the cross-sectional area of the soil control volume, in ㎡; q c is the local geothermal heat flux density, in W / ㎡; Δτ is the time of one year, in s; H is the depth of the medium-deep geothermal buried pipe, in m; ρ is the soil density, in kg / m 3 ; C t is the specific heat capacity of the soil, in kJ / (kg·℃); ΔT is the annual temperature change of the soil control volume; Q g is the heat that needs to be supplemented from renewable geothermal energy, in GJ; N is the number of medium-deep geothermal buried pipe extractions; Step 5: With a designed circulation flow rate of 30 m 3 / h and a designed circulation resistance of 50 mH2O, determine the installed capacity of the heat source side water pump according to the number of medium and deep geothermal buried pipes to be exploited as required; Step 6: According to the steam supply requirements of the project, determine the heating installed capacity of the heat pump unit for centrally producing 120 °C steam, and the installed capacity of the steam transmission and distribution system for centrally transporting and distributing steam. Step Seven: For a local higher steam usage demand Q h，a，3 , determine the heating installed capacity W of the electric heating device to be installed locally eb ; Step 8: After clarifying the system form, that is, according to the annual steam volume required by the project and the system operation energy efficiency, determine the annual cumulative power consumption. The calculation formula is shown in Formula 5. Among them, W is the annual power consumption of the system, with the unit of kWh; η is the electric heating efficiency; COP1 is the heating energy efficiency of the first-stage heat pump system, taken as 4.5; COP2 is the heating energy efficiency of the second-stage heat pump system, taken as 3.

0. Step 9: Subsequently, combining the annual solar radiation intensity, use a photovoltaic power generation unit to provide all the power demand of the modular system, calculate the laying area of the photovoltaic panels, and then obtain the hourly power generation of the photovoltaic throughout the year.

2. An electric-driven heat pump steam production device with zero-carbon operation designed according to the design method described in claim 1, characterized in that: It includes a medium-deep geothermal buried pipe unit (1), a first-stage heat pump unit (2), a second-stage heat pump unit (3), a local electric heating unit (4), a heat recovery unit (5), a photovoltaic power generation unit (6), and a building user unit (7); The medium-deep geothermal buried pipe unit (1) is connected to the first-stage heat pump unit (2) through a geothermal energy transmission and distribution unit; the first-stage heat pump unit (2) is connected to the second-stage heat pump unit (3) through a hot water transmission and distribution unit; the second-stage heat pump unit (3) is connected to the local electric heating unit (4) through a steam transmission and distribution unit; the local electric heating unit (4) is connected to the building user unit (7), and the building user unit (7) is connected to the second-stage heat pump unit through the heat recovery unit (5); the photovoltaic power generation unit (6) is connected to the first-stage heat pump unit (2), the second-stage heat pump unit (3), the hot water transmission and distribution unit, the geothermal energy transmission and distribution unit, the steam transmission and distribution unit, and the local electric heating unit (4).

3. An electric-driven heat pump steam production device with zero-carbon operation designed according to the design method described in claim 2, characterized in that: The medium-deep geothermal buried pipe unit (1) contains one or more medium-deep geothermal buried pipes, and the depth of each medium-deep geothermal buried pipe is 2 - 3 kilometers; on the basis of not exploiting groundwater, the medium-deep geothermal buried pipe extracts medium-deep geothermal energy at 70 - 90 °C underground through the way of wall heat exchange.

4. An electric-driven heat pump steam production device with zero-carbon operation designed according to the design method described in claim 3, characterized in that: The geothermal energy transmission and distribution unit contains one or more variable-frequency water pumps, and the frequency of the water pump is adjustable from 25 Hz to 50 Hz; the heat recovery unit (5) contains a steam condensation waste heat recovery device.

5. An electric-driven heat pump steam production device with zero-carbon operation designed according to the design method described in claim 4, characterized in that: The primary heat pump unit (2) contains one or more magnetic levitation high-efficiency heat pump units; the secondary heat pump unit (3) contains one or more magnetic levitation high-efficiency heat pump units; the primary heat pump unit (2) and the secondary heat pump unit (3) operate in series to achieve cascade temperature rise; the steam transmission and distribution unit contains one or more steam pressurizing pumps for transporting the centrally produced steam to each energy-using end; the local electric heating unit contains one or more distributed steam electric heating systems.

6. An electric-driven heat pump steam production device with zero-carbon operation designed according to the design method described in claim 5, characterized in that: The photovoltaic power generation unit (6) contains photovoltaic panels to provide clean electricity for the operation of the whole system.

7. A working method for an electric-driven heat pump steam production device with zero-carbon operation as described in any one of claims 2-6, characterized in that: The geothermal energy transmission and distribution unit drives the heat source water to extract heat from the soil via the medium-deep geothermal buried pipe unit (1). After the heat source water extracts the medium-deep geothermal energy, it enters the primary heat pump unit (2); the primary heat pump unit (2) absorbs heat from the heat source water and raises the temperature to produce hot water through a compressor. The produced hot water is mixed with the steam condensation waste hot water recovered by the heat recovery unit (5) and then transported to the secondary heat pump unit (3); after the secondary heat pump unit (3) absorbs heat from the hot water, it raises the temperature to produce steam through a compressor, and the produced steam is transported to the building user unit (7) for use via the steam transmission and distribution unit; In areas where higher temperature and pressure steam are locally required, the local electric heating unit (4) is used for heating; the steam used by the building user unit (7) is recovered as steam condensation waste hot water by the heat recovery unit (5); the solar photovoltaic power generation of the photovoltaic power generation unit (6) bears the power consumption of the whole system and drives the operation of the whole system to achieve zero-carbon electricity use.

Images