Desulfurization wastewater reverse osmosis device without water quality softening pretreatment and application thereof
By using an electronic water processor in the desulfurization wastewater reverse osmosis unit to change the ZETA potential of scale-forming ions in the water, combined with a multi-stage reverse osmosis membrane and evaporator system, the problem of membrane fouling and scaling caused by the high hardness of desulfurization wastewater was solved, achieving stable operation and economical zero discharge throughout the entire process.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANGHAI TIANYUAN WATER CO LTD
- Filing Date
- 2026-03-04
- Publication Date
- 2026-06-09
AI Technical Summary
In existing technologies, the high suspended solids, high salinity, and high hardness of desulfurization wastewater from coal-fired power plants make reverse osmosis membranes prone to fouling and chemical softening treatment costly. This also makes it difficult to effectively remove sulfate ions, leading to system instability and equipment damage.
The desulfurization wastewater reverse osmosis device, which does not require water softening pretreatment, uses an electronic water processor to apply an electromagnetic field to the outer wall of the inlet pipe through an induction coil, thereby changing the ZETA potential of scale-forming ions in the water. Combined with the electronic water treatment of a multi-stage reverse osmosis membrane system and an evaporator system, it ensures that calcium and magnesium scale is deposited as fine powder particles, avoiding the formation of large scale layers.
It achieves stable operation of desulfurization wastewater, reduces reagent costs and floor space, extends membrane cleaning cycles, ensures that the evaporator does not scale at high concentration ratios, and provides an economical and stable end-to-end zero-emission solution.
Smart Images
Figure CN122166947A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of water treatment technology, specifically relating to a reverse osmosis device for desulfurization wastewater that does not require water softening pretreatment and its application. Background Technology
[0002] Desulfurization wastewater from coal-fired power plants is characterized by high suspended solids, high salinity, and high hardness, with a total hardness typically ranging from 12,000 mg / L to 30,000 mg / L. Furthermore, the wastewater contains high concentrations of sulfate and fluoride ions, which readily generate insoluble scale that cannot be removed by conventional chemical cleaning, leading to reverse osmosis membrane fouling and even failure.
[0003] Currently, the mainstream technology for zero discharge of desulfurization wastewater in China mainly adopts the "thermal volume reduction-thermal drying" model. Thermal volume reduction typically utilizes systems such as triple-effect evaporators with flue gas as a heat source to concentrate the wastewater 3-5 times. However, this type of process has significant drawbacks: firstly, the evaporation system has high investment costs and a large footprint; secondly, due to the extremely high hardness of the wastewater, severe scaling occurs on the heat exchanger surface, leading to decreased thermal efficiency and frequent shutdowns for maintenance, resulting in extremely high operating costs.
[0004] To alleviate scaling problems, traditional processes typically employ chemical softening pretreatment before concentration. However, this method is not only costly in terms of reagents, but the softening treatment can only reduce hardness to a certain level and cannot effectively remove sulfate ions. Therefore, even after chemical softening, the subsequent reverse osmosis membrane system still faces a severe risk of scaling, easily leading to membrane fouling or even irreversible damage and failure.
[0005] Therefore, there is an urgent industry need to develop a reverse osmosis device for desulfurization wastewater that can eliminate the need for chemical pretreatment and achieve stable operation. Summary of the Invention
[0006] To solve the above-mentioned technical problems, the present invention provides a desulfurization wastewater reverse osmosis device that does not require water softening pretreatment, comprising: an inlet pipeline, a high-pressure pump, a reverse osmosis membrane module, and at least one electronic water processor; The outlet of the high-pressure pump is connected to the inlet of the reverse osmosis membrane module through the water inlet pipe. The reverse osmosis membrane module includes at least one section of reverse osmosis membrane. The electronic water processor includes a controller and a set of induction coils. The set of induction coils is wound around the outer wall of the water inlet pipe and is electrically connected to the controller. The controller is used to send specific electromagnetic signals to the set of induction coils to apply an electromagnetic field to the water inlet pipe through the set of induction coils, thereby changing the ZETA potential of scale-forming ions in the water and degrading organic matter in the water.
[0007] In one embodiment, the electronic water processor is configured as at least one, and each electronic water processor corresponds to a set of induction coils. The induction coils corresponding to the at least one electronic water processor are connected in series on the outer wall of the water inlet pipe along the water flow direction of the water inlet pipe.
[0008] In one embodiment, the controller is used to send a specific electromagnetic signal to the set of induction coils to apply an electromagnetic field to the water inlet pipe through the set of induction coils, thereby adjusting the absolute value of the ZETA potential of scale-forming ions in the water to greater than 30mV.
[0009] In one embodiment, the induction coil is covered with aluminum foil, and the aluminum foil is provided with a metal protective cover. In one embodiment, the winding length of the set of induction coils on the water inlet pipe is at least 1.2 meters.
[0010] In one embodiment, the desulfurization wastewater undergoes physical filtration before entering the desulfurization wastewater reverse osmosis device to ensure that the influent sludge index (SDI) is less than 5.
[0011] In one embodiment, the reverse osmosis membrane assembly is a spiral wound membrane reverse osmosis system or a disc membrane DTRO reverse osmosis system.
[0012] In one embodiment, the reverse osmosis membrane assembly includes a first-stage reverse osmosis membrane operating at a pressure of 50 kg.
[0013] In one embodiment, the reverse osmosis membrane assembly includes a first reverse osmosis membrane and a second reverse osmosis membrane connected in series after the first reverse osmosis membrane, operating at an pressure of 80 kg.
[0014] In one embodiment, the reverse osmosis membrane assembly includes a first reverse osmosis membrane, a second reverse osmosis membrane, and a third reverse osmosis membrane connected in series after the second reverse osmosis membrane, operating at a pressure of 120 kg.
[0015] In one embodiment, the apparatus further includes an evaporator system, the inlet pipe of which is connected to the concentrate outlet of the reverse osmosis membrane module, and a circulation pipe is also provided within the evaporator system. Additional electronic water processors are installed on the water inlet pipe and circulation pipe of the evaporator system. Each electronic water processor includes an induction coil and a controller. The induction coil of the corresponding electronic water processor is wound on the outer wall of the water inlet pipe and circulation pipe of the evaporator system, and each induction coil is electrically connected to the corresponding controller.
[0016] The present invention also proposes an application of the device described above in the field of reverse osmosis membrane concentration of desulfurization wastewater in power plants, wherein the desulfurization wastewater is not chemically softened or hardened before entering the reverse osmosis device.
[0017] The present invention also proposes an application of the above-described device in the field of desulfurization wastewater evaporator concentration. The desulfurization wastewater concentrate treated by an additional electronic water processor is concentrated in the evaporator system, so that the precipitated calcium and magnesium scale is deposited as powder particles with a particle size of less than 40 micrometers at the bottom of the evaporator system and discharged.
[0018] The beneficial effects of this invention are as follows: 1) The raw water for desulfurization wastewater does not require softening or hardening removal, eliminating the traditional chemical softening process; only physical filtration is needed for water intake. This significantly reduces reagent costs, land area requirements, and sludge disposal costs, resolving the industry pain point that chemical methods cannot remove sulfate ions.
[0019] 2) This application uses an electronic water processor to alter the ZETA potential of scale-forming ions in the water, causing its absolute value to tend towards a stable range, thus physically inhibiting scale formation. After treatment, the precipitated monomeric powder particles are discharged with the water flow, preventing the formation of large, hard scale layers on the surface of the reverse osmosis membrane or evaporator. Simultaneously, it effectively prevents hard scale layers from adhering to the reverse osmosis membrane, extending the membrane cleaning cycle to more than two months and preventing membrane fouling and failure.
[0020] 3) Electronic water processors can degrade COD in water online, improve water flowability, and enhance the thermal conductivity of water.
[0021] 4) When linked with the evaporator, even under extreme operating conditions with a concentration ratio as high as 40 times, it can still ensure that no scale forms on the surface of the heat exchanger. This provides a core technological guarantee for achieving economical and stable zero discharge of desulfurization wastewater throughout the entire process. Attached Figure Description
[0022] Figure 1 This is a schematic diagram of a reverse osmosis device for desulfurization wastewater that does not require water softening pretreatment, according to an embodiment of the present invention.
[0023] Figure Labels
[0024] 1. Inlet water pipe; 2. High-pressure pump; 3. Reverse osmosis membrane module; 4. Controller; 5. Induction coil. Detailed Implementation
[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.
[0026] This invention proposes a reverse osmosis device for desulfurization wastewater that does not require water softening pretreatment, specifically designed for treating desulfurization wastewater that is high in salt and hardness (total hardness typically between 12,000 and 30,000 mg / L) and rich in sulfate and fluoride ions. Figure 1 As shown, the device includes: an inlet water pipe 1, a high-pressure pump 2, a reverse osmosis membrane module 3, and at least one electronic water processor. The outlet of the high-pressure pump 2 is connected to the inlet of the reverse osmosis membrane module 3 via the inlet water pipe 1. The electronic water processor is placed nearby and includes a controller 4 and a set of induction coils 5. These induction coils 5 are wound around the outer wall of the inlet water pipe 1 and are electrically connected to the controller 4. The controller 4 sends specific electromagnetic signals to the corresponding set of induction coils 5 to apply an electromagnetic field to the inlet water pipe 1 through these induction coils 5, thereby changing the ZETA potential of scale-forming ions in the water and degrading organic matter in the water.
[0027] In this invention, to ensure the stable operation of the membrane system, the device requires that the influent water meet the physical filtration requirements before passing through the high-pressure pump to remove suspended solids in the water and make the influent sludge index (SDI) less than 5.
[0028] The electronic water processor utilizes the independently developed NS (No Scale) physical water treatment technology, comprising a controller and a set of induction coils. The induction coils are wound around the outer wall of the inlet pipe and electrically connected to the controller, without direct contact with the water. The NS series electronic water processor applies a specific signal to the water via a magnetic field, serving two functions: 1) It can alter and control the ZETA potential value in the water, increasing the solubility of calcium and magnesium ions. After treatment by the electronic water processor, the calcium and magnesium scale precipitated in the water is discharged from the membrane system as fine powder particles with the concentrate flow, preventing the formation of a hard scale layer on the membrane surface, thus ensuring stable membrane operation and eliminating the need for traditional scale inhibitors. 2) This specific signal has a direct chain-breaking degradation function for organic matter (COD). By reducing the COD of the water, membrane fouling can be slowed down, extending the cleaning cycle. The membrane cleaning cycle is more than two months, and after cleaning, the membrane can restore its production capacity and be reused.
[0029] It should be understood that in this application, the absolute value of the ZETA potential is >30mV, at which point the system is stable and has a low tendency to scale. Scale formation is more likely when the absolute value is <10mV, and most likely when the absolute value is near 0mV (isoelectric point). That is, in this application, the controller is used to send electromagnetic signals to a set of induction coils to apply an electromagnetic field to the inlet pipe, thereby adjusting the absolute value of the ZETA potential of scale-forming ions in the water to a stable range greater than 30mV.
[0030] Furthermore, at least one electronic water processor is provided, with each electronic water processor corresponding to a set of induction coils. The induction coils corresponding to at least one electronic water processor are connected in series on the outer wall of the inlet pipe along the water flow direction. That is, multiple electronic water processors can be designed and installed in series to meet different usage requirements, depending on the quality of the incoming water.
[0031] Preferably, the winding length of a set of induction coils on the water inlet pipe is at least 1.2 meters, and more preferably 1.2 meters.
[0032] In one specific embodiment, the power of a single electronic water processor is typically less than 500 watts.
[0033] Preferably, the induction coil is covered with aluminum foil, and the aluminum foil is provided with a metal protective cover to shield electromagnetic radiation and protect the coil.
[0034] Furthermore, the reverse osmosis membrane module is either a spiral wound membrane reverse osmosis system or a disc membrane DTRO reverse osmosis system.
[0035] Furthermore, the reverse osmosis membrane module includes multiple reverse osmosis membranes connected in series, including a first reverse osmosis membrane with an operating pressure of 50 kg. Further still, the multiple reverse osmosis membranes also include a second reverse osmosis membrane connected in series after the first reverse osmosis membrane, with an operating pressure of 80 kg. Still further still, the multiple reverse osmosis membranes also include a third reverse osmosis membrane connected in series after the second reverse osmosis membrane, with an operating pressure of 120 kg.
[0036] Currently, a desulfurization wastewater reverse osmosis system, using a first-stage reverse osmosis membrane with an operating pressure of 50 kg / m² and a recovery rate of over 50%, has been operating stably for one year. If further improvements in recovery rate are needed, a second-stage reverse osmosis membrane with an operating pressure of 80 kg / m² (50% recovery rate) can be connected in series, followed by a third-stage reverse osmosis membrane with an operating pressure of 120 kg / m² (50% recovery rate). Depending on the quality of the desulfurization wastewater, the maximum water recovery rate for the entire system is 87.5% (first stage, sixth stage), and the minimum water recovery rate is greater than 55% (first stage, second stage).
[0037] It should be understood that the recovery rate in this application equals the permeate flow rate divided by the feed flow rate. For example, with a reverse osmosis feed flow rate of 100 tons / hour, a permeate reuse rate of 60 tons / hour, and a concentrate flow rate of 40 tons / hour, the recovery rate is 60%. In a two-stage primary system, the desulfurization wastewater is concentrated through the first membrane stage, and the concentrate is further concentrated in the second membrane stage before being discharged. In a six-stage primary system, the desulfurization wastewater is continuously concentrated through six membrane stages connected in series, and the concentrate is then discharged. Generally, the recovery rate for each two stages is 50%, so the recovery rate for six stages is 87.5%.
[0038] Furthermore, the desulfurization wastewater reverse osmosis unit that does not require water softening pretreatment also includes an evaporator system. The inlet pipe of the evaporator system is connected to the concentrate outlet of the reverse osmosis membrane module, and a circulation pipe is also installed within the evaporator system. If the subsequent membrane concentrate is to be evaporated in the evaporator for zero discharge, additional electronic water processors are installed on both the inlet and circulation pipes of the evaporator system. This cleans the surface of the evaporator heat exchanger, and the precipitated calcium and magnesium scale crystals are powdery particles with a particle size of less than 40 micrometers, which are easily discharged from the bottom of the evaporator. They do not deposit on the heat exchanger, nor do they form large scale; they simply settle at the bottom of the evaporator by gravity and can be easily discharged. At the same time, the electronic water processor can degrade the COD of the water online, improve the water's fluidity, and enhance its thermal conductivity. Specifically, each electronic water processor includes an induction coil and a controller. The corresponding electronic water processor's induction coil is wound around the outer wall of the evaporator system's inlet and circulation pipes, and each induction coil is electrically connected to its corresponding controller.
[0039] The present invention also proposes an application of the device described above in the field of reverse osmosis membrane concentration of desulfurization wastewater in power plants, wherein the desulfurization wastewater is not chemically softened or hardened before entering the reverse osmosis device.
[0040] This invention also proposes an application of the aforementioned device in the field of desulfurization wastewater evaporator concentration. The desulfurization wastewater concentrate, after treatment by an additional electronic water processor, is concentrated within the evaporator system, causing the precipitated calcium and magnesium scale to deposit as powdery particles with a diameter of less than 40 micrometers at the bottom of the evaporator system and be discharged. The membrane concentrate, treated with an electronic water processor, is applied to scale inhibition in the evaporator, resulting in significant crystallization control even at a 40-fold concentration ratio.
[0041] This device has been successfully applied to a power plant desulfurization wastewater treatment project. In March 2025, a reverse osmosis system with an operating pressure of 50 kg / m³, equipped with 9 membranes, was put into operation, achieving a recovery rate of 50-60%. In December 2025, another reverse osmosis system with an operating pressure of 50 kg / m³, equipped with 18 membranes, was put into operation, also achieving a recovery rate of 50-60%. Operation has been stable, and a long-term cleaning cycle of more than two months has been achieved. Based on the physical scale inhibition core technology of the electronic water processor, this solution is currently being extended to higher concentration ratios. Practice has proven that the membrane concentrate treated by this device, after entering the subsequent evaporation system, can support the evaporator to maintain stable operation at a high concentration ratio of 30-50 times.
[0042] The present invention has the following beneficial effects: 1) The raw water for desulfurization wastewater does not require softening or hardening removal, eliminating the traditional chemical softening process; only physical filtration is needed for water intake. This significantly reduces reagent costs, land area requirements, and sludge disposal costs, resolving the industry pain point that chemical methods cannot remove sulfate ions.
[0043] 2) This application uses an electronic water processor to alter the ZETA potential of scale-forming ions in the water, causing its absolute value to tend towards a stable range, thus physically inhibiting scale formation. After treatment, the precipitated monomeric powder particles are discharged with the water flow, preventing the formation of large, hard scale layers on the surface of the reverse osmosis membrane or evaporator. Simultaneously, it effectively prevents hard scale layers from adhering to the reverse osmosis membrane, extending the membrane cleaning cycle to more than two months and preventing membrane fouling and failure.
[0044] 3) Electronic water processors can degrade COD in water online, improve water flowability, and enhance the thermal conductivity of water.
[0045] 4) When linked with the evaporator, even under extreme operating conditions with a concentration ratio as high as 40 times, it can still ensure that no scale forms on the surface of the heat exchanger. This provides a core technological guarantee for achieving economical and stable zero discharge of desulfurization wastewater throughout the entire process.
[0046] It should be understood that the terms "before" and "after" in this article are based on the direction of water flow.
[0047] The embodiments described above are merely further illustrations of the present invention and are not intended to limit the present invention in any other way. The present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding modifications and changes based on the present invention, but all such modifications and changes should fall within the protection scope of the present invention.
Claims
1. A reverse osmosis device for desulfurization wastewater that does not require water softening pretreatment, characterized in that, include: Inlet water pipeline, high-pressure pump, reverse osmosis membrane module and at least one electronic water processor; The outlet of the high-pressure pump is connected to the inlet of the reverse osmosis membrane module through the water inlet pipe. The reverse osmosis membrane module includes at least one section of reverse osmosis membrane. The electronic water processor includes a controller and a set of induction coils. The set of induction coils is wound around the outer wall of the water inlet pipe and is electrically connected to the controller. The controller is used to send specific electromagnetic signals to the set of induction coils to apply an electromagnetic field to the water inlet pipe through the set of induction coils, thereby changing the ZETA potential of scale-forming ions in the water and degrading organic matter in the water.
2. The desulfurization wastewater reverse osmosis device without water softening pretreatment according to claim 1, characterized in that, The electronic water processor is configured as at least one, and each electronic water processor corresponds to a set of induction coils. The induction coils corresponding to the at least one electronic water processor are connected in series on the outer wall of the water inlet pipe along the water flow direction of the water inlet pipe.
3. The desulfurization wastewater reverse osmosis device without water softening pretreatment according to claim 1, characterized in that, The controller is used to send a specific electromagnetic signal to the set of induction coils to apply an electromagnetic field to the water inlet pipe through the set of induction coils, thereby adjusting the absolute value of the ZETA potential of scale-forming ions in the water to greater than 30mV.
4. The desulfurization wastewater reverse osmosis device without water softening pretreatment according to claim 1, characterized in that, The induction coil has one or two of the following characteristics: The induction coil is covered with aluminum foil, and the aluminum foil is provided with a metal protective cover. The winding length of the set of induction coils on the water inlet pipe is at least 1.2 meters.
5. The desulfurization wastewater reverse osmosis device without water softening pretreatment according to claim 1, characterized in that, The device also includes a physical filter disposed at the front end of the high-pressure pump, the physical filter being used to ensure that the influent sludge index (SDI) is less than 5.
6. The desulfurization wastewater reverse osmosis device without water softening pretreatment according to claim 1, characterized in that, The reverse osmosis membrane assembly is a spiral wound membrane reverse osmosis system or a disc membrane type DTRO reverse osmosis system.
7. The desulfurization wastewater reverse osmosis device without water softening pretreatment according to claim 1, characterized in that, The reverse osmosis membrane module includes at least one section of reverse osmosis membrane, specifically one of the following three arrangement structures: This includes the first-stage reverse osmosis membrane, which operates at a pressure of 50 kg. It includes the first reverse osmosis membrane and a second reverse osmosis membrane connected in series after the first reverse osmosis membrane, with an operating pressure of 80 kg. It includes a first reverse osmosis membrane, a second reverse osmosis membrane connected in series after the first reverse osmosis membrane, and a third reverse osmosis membrane connected in series after the second reverse osmosis membrane, with an operating pressure of 120 kg.
8. The desulfurization wastewater reverse osmosis device without water softening pretreatment according to claim 1, characterized in that, It also includes an evaporator system, the inlet pipe of which is connected to the concentrate outlet of the reverse osmosis membrane module, and a circulation pipe is also provided in the evaporator system; Additional electronic water processors are installed on the water inlet pipe and circulation pipe of the evaporator system. Each electronic water processor includes an induction coil and a controller. The induction coil of the corresponding electronic water processor is wound on the outer wall of the water inlet pipe and circulation pipe of the evaporator system, and each induction coil is electrically connected to the corresponding controller.
9. An application of the desulfurization wastewater reverse osmosis device according to any one of claims 1-8 in the field of power plant desulfurization wastewater reverse osmosis membrane concentration, characterized in that, The desulfurization wastewater is not chemically softened or hardened before entering the reverse osmosis unit.
10. An application of the desulfurization wastewater reverse osmosis device according to claim 8 in the field of desulfurization wastewater evaporator concentration, characterized in that, The desulfurization wastewater concentrate, after being treated by an additional electronic water processor, is concentrated in the evaporator system, causing the precipitated calcium and magnesium scale to be deposited as powder particles with a particle size of less than 40 micrometers at the bottom of the evaporator system and discharged.