A seawater desalination energy-saving system

Abstract

The invention discloses a seawater desalination energy-saving method, which comprises the following steps: step 1: simulating the influence of three parameters, namely seawater temperature, seawater recovery rate and feed seawater concentration, on system energy consumption respectively through ROSA software, and performing empirical prediction calculation and analysis on the energy consumption of a reverse osmosis process; step 2: synchronously analyzing the influence of an energy recovery device on the energy consumption change of recovered concentrated seawater; step 3: desalinating reverse osmosis seawater based on the obtained parameter energy consumption influence and device energy consumption influence, the unit energy consumption in the reverse osmosis seawater desalination system reflects the ratio of the energy output and output of the seawater desalination system, and the analysis and calculation result of the ratio can represent the comprehensive level of the reverse osmosis seawater desalination system, and the operation stability of the energy recovery device in the system is improved by performing a qualitative analysis method, and the maximum working pressure of the system is further improved to reduce energy consumption. The invention has the characteristics of reducing total investment cost and reducing energy consumption.

Description

Technical Field

[0001] The invention relates to the technical field of seawater desalination energy saving, in particular to a seawater desalination energy saving system. Background Art

[0002] Desalination technology is currently recognized as one of the best solutions to solve the shortage of fresh water. It uses seawater desalination to produce fresh water. The main desalination methods currently used are reverse osmosis membrane method and distillation method. Among them, reverse osmosis desalination projects are mainly based on direct energy consumption. Because the salt and water in seawater form a stable chemical bond, it is difficult to decompose it. It takes a lot of energy to extract water alone. However, the energy consumption of a desalination project includes not only direct energy consumption, but also indirect energy consumption reflected in the engineering industry chain. Analyzing the energy consumption of the entire project only from the perspective of "end energy consumption" will avoid the existing indirect energy consumption problem. Extracting fresh water from seawater requires a lot of energy and cost, resulting in the energy and cost consumed in the configuration process of the overall desalination project being far higher than the actual plan. Therefore, it is very necessary to design a desalination energy-saving system that reduces the total investment cost and reduces energy consumption. Summary of the invention

[0003] The purpose of the present invention is to provide a seawater desalination energy-saving system to solve the problems raised in the above background technology.

[0004] In order to solve the above technical problems, the present invention provides the following technical solutions: a seawater desalination energy-saving method, comprising the following steps:

[0005] Step 1: Use ROSA software to simulate the effects of three parameters, namely seawater temperature, seawater recovery rate and feed seawater concentration, on system energy consumption, and perform empirical prediction and calculation analysis on the energy consumption of the reverse osmosis process;

[0006] Step 2: Synchronously analyze the impact of energy recovery devices on energy consumption changes in recovering concentrated seawater;

[0007] Step 3: Desalination of seawater by reverse osmosis based on the obtained parameter energy consumption impact and device energy consumption impact.

[0008] According to the above technical solution, the step of performing empirical prediction and calculation analysis on the energy consumption of the reverse osmosis process includes:

[0009] ROSA software was used to simulate and measure the effects of three parameters, namely seawater temperature, seawater recovery rate and feed seawater concentration, on the system energy consumption. Two of the parameters were fixed, and the influence of the other parameter on energy consumption was analyzed by changing it separately.

[0010] According to the above technical solution, the steps of simulating the effects of three parameters, namely, seawater temperature, seawater recovery rate and feed seawater concentration, on system energy consumption respectively by ROSA software include:

[0011] The method of using ROSA software to simulate and measure the effect of seawater temperature on energy consumption is as follows: by fixing the seawater concentration value P and the recovery rate K of the membrane module, the temperature T of the feed seawater is set to a fixed range. The calculation formula of the system energy consumption value X at this time is: , that is, the energy consumption of the system decreases as the seawater temperature increases, that is, the increase in seawater temperature within a fixed range will cause the system pressure to decrease;

[0012] The method of using ROSA software to simulate and measure the effect of seawater recovery rate on energy consumption is as follows: fix the temperature and concentration of the feed seawater, input the seawater recovery rate from small to large within a given range, and judge the change of system energy consumption as the recovery rate of the membrane module increases;

[0013] The method of using ROSA software to simulate and measure the impact of feed seawater concentration on energy consumption is as follows: fix the feed seawater temperature and the recovery rate of the membrane component, let the seawater concentration increase from small to large within a fixed range, judge the change in the feed seawater concentration in the system, and judge the reverse osmosis difficulty of the system membrane component when the seawater concentration gradually increases.

[0014] According to the above technical solution, the step of analyzing the influence of the energy recovery device on the change of energy consumption of recovering concentrated seawater includes:

[0015] By comparing the unit water production energy consumption and total energy consumption under different seawater concentration conditions, the total energy consumption of seawater solutions with different parameter concentrations and the total energy consumption of seawater solutions are analyzed to determine the changes in the total energy consumption curve.

[0016] According to the above technical solution, the method steps for qualitative control analysis of the state of the energy recovery device include:

[0017] By adjusting the speed of the high-pressure pump to indirectly change the flow conditions of the energy recovery device, the working pressure of the energy recovery device in the reverse osmosis seawater system is adjusted, the energy recovery device is set to a non-working state and a working state, and the pressure and flow before the reverse osmosis membrane in the system are adjusted. The data changes of the water production rate in the system are recorded, and the changes in the water production energy consumption at this time are analyzed.

[0018] According to the above technical solution, the method steps for reverse osmosis seawater desalination include:

[0019] Step 1: After the low-pressure raw seawater passes through the filter from the test water tank, part of it passes through the flow regulating valve to enter the high-pressure seawater pump, and the other part passes through the flow regulating valve to enter the low-pressure fresh seawater inlet of the energy recovery device;

[0020] Step 2: The high-pressure seawater pressurized by the high-pressure pump enters the reverse osmosis membrane assembly and becomes fresh water, which is separated out through the flow control valve and flows back to the test water tank. The high-pressure concentrated brine that does not pass through the reverse osmosis membrane enters the high-pressure concentrated brine inlet of the pressure exchanger of the energy recovery device;

[0021] Step 3: Control the operating pressure of the system by adjusting the inverter of the high-pressure pump and changing the opening of the bypass valve of the high-pressure pipeline. Adjust the high-pressure fluid flow of the energy recovery device by changing the inverter output frequency of the booster pump. Adjust the low-pressure fluid flow of the energy recovery device by changing the inverter frequency of the low-pressure feed water pump and the opening of the pressure relief brine back pressure valve.

[0022] Step 4: When the energy recovery device rotates at high speed, the low-pressure fresh seawater reacts with the high-pressure concentrated brine to achieve pressure energy exchange, and the high-pressure concentrated brine becomes low-pressure concentrated brine, which is discharged through the low-pressure concentrated brine outlet and flow control valve of the energy recovery device;

[0023] Step 5: After being discharged, the low-pressure fresh seawater enters the energy recovery device through the flow regulating valve, obtains energy in the energy collision, and becomes high-pressure fresh seawater, which enters the booster pump of the energy recovery device and is pressurized by the plunger booster pump. The pressurized high-pressure fresh seawater is output to the reverse osmosis membrane and fresh water is produced again.

[0024] According to the above technical solution, the seawater desalination energy-saving system includes:

[0025] Parameter energy consumption impact analysis module, used to analyze the impact of three parameters, seawater temperature, seawater recovery rate, and feed seawater concentration, on the energy consumption of the seawater desalination system;

[0026] The device energy consumption impact analysis module is used to analyze the impact of energy recovery devices on the energy consumption changes of concentrated seawater recovery;

[0027] The seawater desalination energy-saving module is used to desalinate seawater by reverse osmosis based on the obtained parameter energy consumption impact and device energy consumption impact.

[0028] According to the above technical solution, the parameter energy consumption impact analysis module includes:

[0029] ROSA software simulation module, used to use ROSA software to simulate and measure the impact of multiple parameters on system energy consumption;

[0030] The energy consumption influence law analysis module is used to fix two simulated parameter quantities and analyze the influence law of another parameter quantity on energy consumption by using the separate change of the other parameter quantity;

[0031] The empirical prediction calculation and analysis module is used to perform empirical prediction calculation and analysis on the energy consumption of the reverse osmosis process.

[0032] According to the above technical solution, the device energy consumption impact analysis module includes:

[0033] An energy recovery device module for analyzing the energy recovery device as a load element of the output pressure and flow of the high-pressure pump;

[0034] The total energy consumption curve change judgment module is used to analyze the total energy consumption of seawater solutions with different parameter concentrations and the total energy consumption of seawater solutions, and judge the change of the total energy consumption curve;

[0035] The water production energy consumption change analysis module is used to analyze the water production energy consumption change of the system when adjusting the pressure and flow rate before the reverse osmosis membrane;

[0036] The qualitative analysis module is used to set the working state of the energy recovery device in the system to conduct qualitative analysis on the impact on energy consumption.

[0037] According to the above technical solution, the seawater desalination energy-saving module includes:

[0038] Reverse osmosis seawater desalination module, used for reverse osmosis seawater desalination;

[0039] Comprehensive level response module, used to analyze the comprehensive level of the reverse osmosis desalination system according to the ratio of the energy output and output of the desalination system;

[0040] The unit energy consumption curve acquisition module is used to obtain the unit energy consumption curve under different seawater concentrations.

[0041] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0042] 1. By using ROSA software to simulate and measure the effects of three parameters, namely seawater temperature, seawater recovery rate and feed seawater concentration, on energy consumption, two of the parameters are fixed, and the influence of the other parameter on energy consumption is analyzed by the change of the other parameter alone. The energy consumption of the reverse osmosis process is empirically predicted and calculated to ensure that the system can reduce energy consumption and make more reasonable later parameter settings, while saving operating costs;

[0043] 2. Based on the qualitative analysis of the working status of the energy recovery device in the system, reverse osmosis seawater desalination is carried out based on the obtained parameter energy consumption impact and device energy consumption impact, and the relevant control configuration is analyzed to make the inlet and outlet flow of the energy recovery device reach a balanced state, improve the operating stability of the energy recovery device, increase the maximum working pressure of the system, and reduce the unit water production energy consumption of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0045] Figure 1 A flow chart of a seawater desalination energy-saving method provided in Embodiment 1 of the present invention;

[0046] Figure 2 A schematic diagram of the module composition of a seawater desalination energy-saving system provided in Embodiment 2 of the present invention. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] Embodiment 1: Figure 1 This is a flow chart of a seawater desalination energy-saving method provided in Embodiment 1 of the present invention. This embodiment can be applied to seawater desalination scenarios. This method can be executed by a seawater desalination energy-saving system provided in this embodiment. Figure 1 As shown, the method specifically comprises the following steps:

[0049] Step 1: Use ROSA software to simulate the effects of three parameters, namely seawater temperature, seawater recovery rate and feed seawater concentration, on system energy consumption, and perform empirical prediction and calculation analysis on the energy consumption of the reverse osmosis process;

[0050] In the embodiment of the present invention, the principle of the reverse osmosis process is: under pressure drive, the solvent as water passes through the reverse osmosis membrane into the low-pressure side of the produced water, and other components including salt and impurities in the solution are blocked on the high-pressure side of the membrane and discharged with the concentrated seawater to achieve an effective separation process. In the ROSA software, a seawater booster pump is used to pump fresh seawater into the pretreatment device, and the qualified feed seawater after pretreatment is pressurized by the high-pressure pump, and further pressurized to the rated operating pressure of seawater desalination by pumping into the differential pressure exchange energy recovery device, and then enters the reverse osmosis membrane assembly, and the desalinated water passes through the reverse osmosis membrane and is then drawn out from the membrane stack, and the remaining reverse osmosis high-pressure seawater enters the energy recovery device, and is discharged from the system after the residual pressure energy exchange. Therefore, the ROSA software is used to simulate and measure the influence of three parameters, namely, seawater temperature, seawater recovery rate, and feed seawater concentration, on energy consumption, and two of the parameters are fixed, and the influence of the other parameter on energy consumption is analyzed by the separate change of the other parameter.

[0051] For example, the method of using ROSA software to simulate and measure the effect of seawater temperature on energy consumption is as follows: by fixing the seawater concentration value P and the recovery rate K of the membrane module, the temperature T of the feed seawater is set to a fixed range, and the calculation formula of the system energy consumption value X at this time is: , that is, the energy consumption of the system decreases as the seawater temperature rises. Because the temperature changes within a range, the activity will increase linearly when the temperature exceeds the range threshold, resulting in an increase in seawater permeability and an increase in the salt content of the finished water. It is judged that when the seawater concentration value and the recovery rate of the membrane module are fixed, the permeability of the reverse osmosis membrane in the reverse osmosis membrane module changes with the increase in temperature. When the seawater temperature increases within a fixed range, more salts pass through the reverse osmosis membrane, that is, the increase in seawater temperature within a fixed range will cause the system pressure to decrease accordingly;

[0052] Exemplarily, the method of using ROSA software to simulate and measure the effect of seawater recovery rate on energy consumption is as follows: the temperature and concentration of feed seawater are fixed, the seawater recovery rate is input from small to large within a given range, and the energy consumption of the system is judged to change with the increase of the recovery rate of the membrane module. When the recovery rate of the membrane module gradually increases within the range, the unit volume of raw water in the system increases with the increase of the seawater recovery rate. The finished water is also increased, and it is judged that the energy consumption per unit of finished water decreases, that is, the energy consumption of the system decreases. When the recovery rate of the membrane module gradually increases within the range, the unit volume of raw water in the system decreases with the increase of the seawater recovery rate. The energy consumption per unit of finished water is judged to increase, that is, the energy consumption of the system increases.

[0053] Exemplarily, the method of using ROSA software to simulate and measure the impact of feed seawater concentration on energy consumption is as follows: fix the feed seawater temperature and the recovery rate of the membrane assembly, allow the seawater concentration to increase from small to large within a fixed range, determine the change in feed seawater concentration in the system, and determine the degree of reverse osmosis difficulty of the system membrane assembly after the seawater concentration gradually increases. When the concentration is higher and the system pressure is greater, the power consumption of the high-pressure pump in the system will also increase, causing the energy consumption per unit of finished water in the system to increase. When the concentration is higher and the system pressure is lower, the power consumption of the high-pressure pump in the system remains within the existing range, and the energy consumption per unit of finished water in the system remains in a normal state, that is, the energy consumption has not increased.

[0054] Step 2: Synchronously analyze the impact of energy recovery devices on energy consumption changes in recovering concentrated seawater;

[0055] In the embodiment of the present invention, the energy consumption of the reverse osmosis desalination system mainly consists of the energy consumption of the motor-driven high-pressure seawater pump to produce high-pressure water and the energy consumption of the motor-driven energy recovery device to exchange pressure energy and boost pressure. The energy recovery device is coupled to the reverse osmosis system, and mainly realizes the pressure increase of low-pressure seawater to the reverse osmosis membrane inlet pressure. During the boosting process, the pressure energy of the high-pressure salt water can be directly transferred to the boosted seawater. The ratio of the pressure energy of the boosted seawater to the pressure energy of the high-pressure salt water is called the direct efficiency of the boosting process. By comparing the unit water production energy consumption and the total energy consumption under different seawater concentration conditions, the total energy consumption of the seawater solution with different parameter concentrations and the total energy consumption of the seawater solution are analyzed, and the direct efficiency of the boosting process is judged. The total energy consumption curve changes. When the speed of the energy recovery device remains constant, the total energy consumption is expressed as the energy consumption of the high-pressure pump. When the total energy consumption curve increases with the increase of the speed of the high-pressure pump, the total energy consumption increases with the increase of the speed of the high-pressure pump. At this time, the system water production energy consumption curve presents a linear positive correlation. When the system produces more fresh water, the unit water production energy consumption is smaller, that is, the higher the concentration of the seawater solution in the system, the greater the load pressure of the high-pressure pump in the system needs to be, that is, the energy consumption of the high-concentration seawater solution is higher than the total energy consumption of the low-concentration seawater solution. When the salinity of the feed water is changed, the energy consumption and working pressure of the system will also increase linearly with the increase of the salinity of the feed water, that is, the higher the salinity of the raw water, the more energy is required;

[0056] Exemplarily, when the reverse osmosis seawater desalination system is working, the energy recovery device acts as a load element for the output pressure and flow of the high-pressure pump. Under the premise that the speed of the energy recovery device is constant, the speed of the high-pressure pump is increased, the flow rate of the high-pressure pump increases, and the high-pressure concentrated brine inlet flow of the energy recovery device increases, that is, the high-pressure and low-pressure fluids that simultaneously exchange pressure energy in the device increase, the load increases, and the system working pressure increases accordingly. Therefore, the working pressure of the energy recovery device in the reverse osmosis seawater system is adjusted by indirectly changing the flow conditions of the energy recovery device by adjusting the speed of the high-pressure pump, and the energy recovery device is set not to Work, fully open the raw water pump reflux valve to test the water production rate and system energy consumption of the reverse osmosis membrane group, open the raw water pump to allow fresh seawater in the system to enter the reverse osmosis membrane group through the raw water pump and the high-pressure pump, adjust the cone valve to connect the external concentrated brine pipeline to return the seawater tank, adjust the cone valve to build up pressure in front of the reverse osmosis membrane group, when the pressure in front of the membrane reaches the water production pressure, fresh water is generated, at this time, continue to increase the pressure in front of the reverse osmosis membrane, the fresh water generation flow rate increases, adjust the opening degree of the cone valve and the speed of the high-pressure pump, adjust the pressure and flow in front of the reverse osmosis membrane, record the data changes of the water production rate in the system, and analyze the changes in water production energy consumption at this time;

[0057] Exemplarily, the raw water pump, high-pressure pump, and energy recovery device are set to work normally, the speed of each motor is adjusted to balance the flow of the energy recovery device, and measurements are performed with pressure energy recovery and reduction of average energy consumption as the core. By changing the parameters of flow, pre-membrane pressure and fresh seawater concentration, two seawater solutions of low fixed concentration seawater and standard concentration are set, the flow pressure readings are recorded, and the salinity meter is used to directly measure the artificial seawater concentrations at the high-pressure brine outlet, low-pressure brine outlet, and low-pressure fresh seawater inlet of the energy recovery device. The fluid mixing rate of the energy recovery device is calculated, and the changes in water production energy consumption under different parameter data of the energy recovery device are analyzed.

[0058] Step 3: Desalination of seawater by reverse osmosis based on the obtained parameter energy consumption impact and device energy consumption impact;

[0059] In an embodiment of the present invention, the method for reverse osmosis desalination is:

[0060] Step 1: After the low-pressure raw seawater passes through the filter from the test water tank, part of it passes through the flow regulating valve to enter the high-pressure seawater pump, and the other part passes through the flow regulating valve to enter the low-pressure fresh seawater inlet of the energy recovery device;

[0061] Step 2: The high-pressure seawater pressurized by the high-pressure pump enters the reverse osmosis membrane assembly and becomes fresh water, which is separated out through the flow control valve and flows back to the test water tank. The high-pressure concentrated brine that does not pass through the reverse osmosis membrane enters the high-pressure concentrated brine inlet of the pressure exchanger of the energy recovery device;

[0062] Step 3: Control the operating pressure of the system by adjusting the inverter of the high-pressure pump and changing the opening of the bypass valve of the high-pressure pipeline. Adjust the high-pressure fluid flow of the energy recovery device by changing the inverter output frequency of the booster pump. Adjust the low-pressure fluid flow of the energy recovery device by changing the inverter frequency of the low-pressure feed water pump and the opening of the pressure relief brine back pressure valve.

[0063] Step 4: When the energy recovery device rotates at high speed, the low-pressure fresh seawater reacts with the high-pressure concentrated brine to achieve pressure energy exchange, and the high-pressure concentrated brine becomes low-pressure concentrated brine, which is discharged through the low-pressure concentrated brine outlet and flow control valve of the energy recovery device;

[0064] Step 5: After being discharged, the low-pressure fresh seawater enters the energy recovery device through the flow control valve, obtains energy from the energy collision, and becomes high-pressure fresh seawater, which enters the booster pump of the energy recovery device, and is pressurized by the plunger booster pump. The pressurized high-pressure fresh seawater is output to the reverse osmosis membrane to produce fresh water again;

[0065] Exemplarily, the unit energy consumption in the reverse osmosis desalination system reflects the ratio of the energy output and output of the desalination system, directly represents the comprehensive level of the reverse osmosis desalination system, and obtains the unit energy consumption curve under different seawater concentrations. By adjusting the existing reverse osmosis desalination system, the low-pressure seawater is periodically drawn out at the moment of the switch switching to alleviate the pressure and flow fluctuations of the low-pressure seawater. As the speed of the high-pressure pump increases, the system unit water production energy consumption gradually decreases, the slope of the curve gradually decreases and tends to be flat. The low-concentration seawater solution has a lower unit water production energy consumption. The unit energy consumption of the high-concentration seawater solution gradually decreases with the increase of the speed. The difference between the unit energy consumption of the high-concentration seawater solution and the unit water production energy consumption of the low-concentration seawater solution gradually decreases, so that the inlet and outlet flow of the energy recovery device can reach a balanced state, thereby improving the operating stability of the energy recovery device and further increasing the maximum working pressure of the system.

[0066] Embodiment 2: Embodiment 2 of the present invention provides a seawater desalination energy-saving system. Figure 2 A schematic diagram of the module composition of a seawater desalination energy-saving system provided in the second embodiment of the present invention is shown in FIG. Figure 2 As shown, the system includes:

[0067] Parameter energy consumption impact analysis module, used to analyze the impact of three parameters, seawater temperature, seawater recovery rate, and feed seawater concentration, on the energy consumption of the seawater desalination system;

[0068] The device energy consumption impact analysis module is used to analyze the impact of energy recovery devices on the energy consumption changes of concentrated seawater recovery;

[0069] The seawater desalination energy-saving module is used to desalinate seawater by reverse osmosis based on the obtained parameter energy consumption impact and device energy consumption impact.

[0070] In some embodiments of the present invention, the parameter energy consumption impact analysis module includes:

[0071] ROSA software simulation module, used to use ROSA software to simulate and measure the impact of multiple parameters on system energy consumption;

[0072] The energy consumption influence law analysis module is used to fix two simulated parameter quantities and analyze the influence law of another parameter quantity on energy consumption by using the separate change of the other parameter quantity;

[0073] The empirical prediction calculation and analysis module is used to perform empirical prediction calculation and analysis on the energy consumption of the reverse osmosis process.

[0074] In some embodiments of the present invention, the device energy consumption impact analysis module includes:

[0075] An energy recovery device module for analyzing the energy recovery device as a load element of the output pressure and flow of the high-pressure pump;

[0076] The total energy consumption curve change judgment module is used to analyze the total energy consumption of seawater solutions with different parameter concentrations and the total energy consumption of seawater solutions, and judge the change of the total energy consumption curve;

[0077] The water production energy consumption change analysis module is used to analyze the water production energy consumption change of the system when adjusting the pressure and flow rate before the reverse osmosis membrane;

[0078] The qualitative analysis module is used to set the working state of the energy recovery device in the system to conduct qualitative analysis on the impact on energy consumption.

[0079] In some embodiments of the present invention, the seawater desalination energy-saving module includes:

[0080] Reverse osmosis seawater desalination module, used for reverse osmosis seawater desalination;

[0081] Comprehensive level response module, used to analyze the comprehensive level of the reverse osmosis desalination system according to the ratio of the energy output and output of the desalination system;

[0082] The unit energy consumption curve acquisition module is used to obtain the unit energy consumption curve under different seawater concentrations.

[0083] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0084] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A seawater desalination energy-saving method, characterized in that: The method comprises the following steps: Step 1: Use ROSA software to simulate the effects of three parameters, namely seawater temperature, seawater recovery rate and feed seawater concentration, on system energy consumption, and perform empirical prediction and calculation analysis on the energy consumption of the reverse osmosis process; Step 2: Synchronously analyze the impact of the energy recovery device on the energy consumption change of concentrated seawater recovery, including qualitative control analysis of the state of the energy recovery device; The method steps for qualitative control analysis of the state of the energy recovery device include: By indirectly changing the flow conditions of the energy recovery device by adjusting the speed of the high-pressure pump, the working pressure of the energy recovery device in the reverse osmosis seawater system is adjusted, the non-working state and working state of the energy recovery device are set, and the pressure and flow before the reverse osmosis membrane in the system are adjusted, and the data changes of the water production rate in the system are recorded to analyze the changes in the water production energy consumption at this time; The energy consumption of the reverse osmosis desalination system mainly consists of the energy consumption of the motor-driven high-pressure seawater pump to produce high-pressure water and the energy consumption of the motor-driven energy recovery device for pressure energy exchange and pressurization. The energy recovery device is coupled to the reverse osmosis system to increase the pressure of low-pressure seawater to the inlet pressure of the reverse osmosis membrane. During the pressurization process, the pressure of the high-pressure salt water is transmitted to the pressurized seawater. The ratio of the pressure energy of the pressurized seawater to the pressure energy of the high-pressure salt water is called the direct efficiency of the pressurization process. By comparing the unit water production energy consumption and the total energy consumption under different seawater concentration conditions, the total energy consumption of seawater solutions with different parameter concentrations and the total energy consumption of seawater solutions are analyzed to determine the changes in the total energy consumption curve; Step 3: Desalination of seawater by reverse osmosis based on the obtained parameter energy consumption impact and device energy consumption impact.

2. A seawater desalination energy-saving method according to claim 1, characterized in that: The step of performing empirical prediction and calculation analysis on the energy consumption of the reverse osmosis process comprises: ROSA software was used to simulate and measure the effects of three parameters, namely seawater temperature, seawater recovery rate and feed seawater concentration, on the system energy consumption. Two of the parameters were fixed, and the influence of the other parameter on energy consumption was analyzed by changing it separately.

3. A seawater desalination energy-saving method according to claim 2, characterized in that: The steps of simulating the effects of three parameters, namely, seawater temperature, seawater recovery rate and feed seawater concentration, on system energy consumption respectively by using ROSA software include: The method of using ROSA software to simulate and measure the effect of seawater temperature on energy consumption is as follows: by fixing the seawater concentration value P and the recovery rate K of the membrane module, the temperature T of the feed seawater is set to a fixed range. The calculation formula of the system energy consumption value X at this time is: , that is, the energy consumption of the system decreases as the seawater temperature increases, that is, the increase in seawater temperature within a fixed range will cause the system pressure to decrease; The method of using ROSA software to simulate and measure the effect of seawater recovery rate on energy consumption is as follows: fix the temperature and concentration of the feed seawater, input the seawater recovery rate from small to large within a given range, and judge the change of system energy consumption as the recovery rate of the membrane module increases; The method of using ROSA software to simulate and measure the impact of feed seawater concentration on energy consumption is as follows: fix the feed seawater temperature and the recovery rate of the membrane component, let the seawater concentration increase from small to large within a fixed range, judge the change in the feed seawater concentration in the system, and judge the reverse osmosis difficulty of the system membrane component when the seawater concentration gradually increases.

4. A seawater desalination energy-saving method according to claim 3, characterized in that: The step of analyzing the influence of the energy recovery device on the change of energy consumption of recovering concentrated seawater includes: By comparing the unit water production energy consumption and total energy consumption under different seawater concentration conditions, the total energy consumption of seawater solutions with different parameter concentrations and the total energy consumption of seawater solutions are analyzed to determine the changes in the total energy consumption curve.

5. A seawater desalination energy-saving method according to claim 4, characterized in that: The method steps for reverse osmosis seawater desalination include: Step 1: After the low-pressure raw seawater passes through the filter from the test water tank, part of it passes through the flow regulating valve to enter the high-pressure seawater pump, and the other part passes through the flow regulating valve to enter the low-pressure fresh seawater inlet of the energy recovery device; Step 2: The high-pressure seawater pressurized by the high-pressure pump enters the reverse osmosis membrane assembly and becomes fresh water, which is separated out through the flow control valve and flows back to the test water tank. The high-pressure concentrated brine that does not pass through the reverse osmosis membrane enters the high-pressure concentrated brine inlet of the pressure exchanger of the energy recovery device; Step 3: Control the operating pressure of the system by adjusting the inverter of the high-pressure pump and changing the opening of the bypass valve of the high-pressure pipeline. Adjust the high-pressure fluid flow of the energy recovery device by changing the inverter output frequency of the booster pump. Adjust the low-pressure fluid flow of the energy recovery device by changing the inverter frequency of the low-pressure feed water pump and the opening of the pressure relief brine back pressure valve. Step 4: When the energy recovery device rotates at high speed, the low-pressure fresh seawater reacts with the high-pressure concentrated brine to achieve pressure energy exchange, and the high-pressure concentrated brine becomes low-pressure concentrated brine, which is discharged through the low-pressure concentrated brine outlet and flow control valve of the energy recovery device; Step 5: After being discharged, the low-pressure fresh seawater enters the energy recovery device through the flow regulating valve, obtains energy in the energy collision, and becomes high-pressure fresh seawater, which enters the booster pump of the energy recovery device and is pressurized by the plunger booster pump. The pressurized high-pressure fresh seawater is output to the reverse osmosis membrane and fresh water is produced again.

6. A seawater desalination energy-saving system for executing a seawater desalination energy-saving method according to claim 1, characterized in that: The system comprises: Parameter energy consumption impact analysis module, used to analyze the impact of three parameters, seawater temperature, seawater recovery rate, and feed seawater concentration, on the energy consumption of the seawater desalination system; The device energy consumption impact analysis module is used to analyze the impact of energy recovery devices on the energy consumption changes of recovered concentrated seawater; The seawater desalination energy-saving module is used to desalinate seawater by reverse osmosis based on the obtained parameter energy consumption impact and device energy consumption impact.

7. The seawater desalination energy-saving system according to claim 6, characterized in that: The parameter energy consumption impact analysis module includes: ROSA software simulation module, used to use ROSA software to simulate and measure the impact of multiple parameters on system energy consumption; Energy consumption influence law analysis module, used to fix two simulated parameter quantities and analyze the influence law of another parameter quantity on energy consumption by using the separate change of the other parameter quantity; The empirical prediction calculation and analysis module is used to perform empirical prediction calculation and analysis on the energy consumption of the reverse osmosis process.

8. The seawater desalination energy-saving system according to claim 7, characterized in that: The device energy consumption impact analysis module includes: An energy recovery device module for analyzing the energy recovery device as a load element of the output pressure and flow of the high-pressure pump; The total energy consumption curve change judgment module is used to analyze the total energy consumption of seawater solutions with different parameter concentrations and the total energy consumption of seawater solutions, and judge the change of the total energy consumption curve; The water production energy consumption change analysis module is used to analyze the water production energy consumption change of the system when adjusting the pressure and flow rate before the reverse osmosis membrane; The qualitative analysis module is used to set the working state of the energy recovery device in the system to conduct qualitative analysis on the impact on energy consumption.

9. The seawater desalination energy-saving system according to claim 8, characterized in that: The seawater desalination energy-saving module comprises: Reverse osmosis seawater desalination module, used for reverse osmosis seawater desalination; Comprehensive level response module, used to analyze the comprehensive level of the reverse osmosis desalination system according to the ratio of the energy output and output of the desalination system; The unit energy consumption curve acquisition module is used to obtain the unit energy consumption curve under different seawater concentrations.

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