Bath wastewater purification and heat exchange balance cyclic utilization method and system

Abstract

The invention discloses a bath wastewater purification and heat exchange balance cyclic utilization method and system, and the method comprises the following steps: collecting bath wastewater, filtering the wastewater and solid wastes to obtain filtered wastewater, and carrying out sterilization treatment, grease decomposition treatment and pH value adjustment treatment on the filtered wastewater to obtain purified wastewater; purified water and concentrated water are obtained after the purified wastewater is filtered through a microfiltration assembly and a reverse osmosis assembly, the purified water is sent to bath heating equipment, and the concentrated water is sent to a filtered wastewater purification position to be purified and filtered again; and a bathing heat exchange circulation optimization model is established according to the number of bathers, the bathing time, the bathing flow and the real-time temperature of the purified water, and the temperature of hot water in a heating inner container of bathing heating equipment is adjusted in real time according to the model, so that the temperature of bathing water used by the number of bathers within the bathing time is kept within the set bathing range. According to the invention, the integration of bath sewage purification and heat exchange cyclic utilization is realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of water treatment, and more specifically, relates to a method and system for purifying bath wastewater, balancing heat exchange, and recycling it cyclically. Background Art

[0002] Bath wastewater is a kind of building domestic sewage with relatively low pollution degree, and has characteristics such as large water volume (about 30% in residential buildings and about 70% in hotels and restaurants), easy to separate, and convenient to collect. There are two sources of pollutants in bath wastewater: one is the secretions discharged from the human skin, mainly including substances such as potassium, sodium, chlorine, urea, uric acid, creatinine, and lactic acid contained in sweat, and substances such as fatty acids, cholesterol, protein exudate, and sebaceous gland cell debris contained in sebum; the other is the detergents used in bath activities. At present, most bath water is directly discharged after being used once, which not only increases the burden on urban drainage and water treatment, but also wastes precious water resources. If it can be collected, treated, and comprehensively reused, it can not only provide a large amount of raw water, but also reduce the treatment difficulty, lower the treatment cost, and create good economic, environmental, and social benefits.

[0003] To solve the above problems, patent document CN100503993C discloses a comprehensive recycling equipment and method for hotel bath wastewater treatment. The equipment includes a pipeline mixer, a metering pump, a hair filter, a chemical dosing tank, a fiber ball filter, an ultrafiltration membrane module, a nanofiltration membrane module, a ClO2 disinfection tank, a storage water tank, a security filter element, and a pressurizing pump. The bath wastewater generated in the hotel is centrally collected and filtered by a new type of polyester high-elastic yarn micro-flocculation fiber and ultrafiltered. After the effluent meets the requirements of "Quality Standard for Reclaimed Urban Miscellaneous Water for Urban Reuse" (GB / T 18920-2002), it can be reused for flushing toilets and greening in the hotel. The remaining ultrafiltration effluent is further treated by a nanofiltration membrane device and disinfection. After the treated effluent meets the "Hygienic Standard for Drinking Water" (GB5749-85), it can be reused for higher water quality requirements such as laundry and bathing in the hotel.

[0004] This process and related equipment have a simple flow and are easy to operate and manage, and are very suitable for the intermediate water reuse in hotels. However, in this process, the bath sewage is filtered and separated. Part of it is reused for flushing toilets and greening in the hotel, and the remaining ultrafiltration effluent is further treated by a nanofiltration membrane device and disinfection and reused for laundry and bathing in the hotel. On the one hand, it fails to consider making full use of the waste heat of the bath sewage to exchange heat and heat the bath water temperature faster, resulting in problems such as time-consuming and power-consuming heating. In addition, this method does not consider the problem of unbalanced bath water temperature when multiple people take baths at the same time. Summary of the Invention

[0005] In view of the above deficiencies or improvement requirements of the prior art, the present invention provides a control method and system for purifying and recycling bath wastewater. An optimized model for bath heat exchange and recycling is established based on the number of bathers, bath time, bath flow rate, and the real-time temperature of the purified water. According to this model, the hot water temperature in the heating inner tank of the bath heating equipment is adjusted in real time, so that the water temperature of the bath water used by the bathers within the bath time remains within the set bath range, realizing the integration of bath sewage purification and heat exchange recycling.

[0006] To achieve the above object, according to the first aspect of the present invention, a method for purifying, heat exchanging, and balancing the recycling of bath wastewater is provided, including the following steps:

[0007] S100: After collecting the bath wastewater, the wastewater is filtered from solid waste to obtain filtered wastewater. After the filtered wastewater is subjected to sterilization treatment, oil decomposition treatment, and pH value adjustment treatment, purified wastewater is obtained;

[0008] S200: After the purified wastewater is filtered through a microfiltration module and a reverse osmosis module, purified water and concentrated water are obtained. The purified water is sent to the bath heating equipment, and the concentrated water is sent to the filtered wastewater purification area for further purification and filtration treatment;

[0009] S300: An optimized model for bath heat exchange and recycling is established based on the number of bathers, bath time, bath flow rate, and the real-time temperature of the purified water. According to this model, the hot water temperature in the heating inner tank of the bath heating equipment is adjusted in real time, so that the water temperature of the bath water used by the bathers within the bath time remains within the set bath range.

[0010] Further, the establishment of the optimized model for bath heat exchange and recycling in step S300 includes:

[0011] S301: Combining the actual situation of the bath scenario, dynamically predicting the total heat demand Q for multiple people taking baths simultaneously T is:

[0012]

[0013] where: Q t is the water flow rate, N t is the number of bathers at time t, representing the scale of water use load, t s is the average bath time per person, c p is the specific heat capacity of water, T r 、T c are the target outlet water temperature and the cold water inlet temperature respectively, representing the temperature of the unheated cold water before entering the heating system or heat exchanger, Q indiv represents the heat of water used per person.

[0014] Further, the establishment of the optimized model for bath heat exchange and recycling in step S300 includes:

[0015] S302: During the wastewater purification process, after separating solid impurities and chemical pollutants through sedimentation, filtration, and sterilization, the waste heat Q of the wastewater is recovered in real time. w That is:

[0016]

[0017] Where: m t = N t ·Q t ·ρ, representing the mass of the wastewater, and T w represents the temperature of the wastewater, which depends on the user's drainage temperature, and T a represents the ambient temperature.

[0018] Furthermore, establishing the bath heat exchange cycle optimization model in step S300 includes:

[0019] S303: The latent heat and sensible heat recovered from the steam generated during the bathing process through the condensation device are respectively:

[0020]

[0021] Where: Q s is the heat recovered from the steam, and Q c is the heat recovered from the sensible heat of the condensed water. m s represents the mass of the steam, L represents the latent heat of vaporization of the steam, and T c represents the temperature of the condensed water;

[0022] Thus, the total waste heat recovery amount is obtained as: Q r = Q w + Q s + Q c .

[0023] Furthermore, establishing the bath heat exchange cycle optimization model in step S300 includes:

[0024] S304: Based on the total heat demand and total waste heat recovery amount of multiple people bathing simultaneously, the dynamic optimization model of the heat exchanger is established as:

[0025] Q i，in = Q w，i + Q s，i + Q h，i Where: Q i，in is the input heat allocated to the i-th heat exchanger; Q w，i is the waste heat of the wastewater allocated to the i-th heat exchanger, Q s，i is the steam heat allocated to the i-th heat exchanger, Q h，i is the sensible heat allocated to the i-th heat exchanger, and the output heat is: Q i，out = Q i，in·η i ,η i is the heat exchanger efficiency, and the heat exchanger load balance is:

[0026]

[0027] where: ε is the threshold value for restricting the heat output fluctuation of the heat exchanger.

[0028] Further, the establishment of the bath heat exchange cycle optimization model in step S300 includes:

[0029] S305: The total supplementary heat is: Q h = Q T - Q r , and based on the supplementary heat Q h The heat distributed to each heat exchanger is established as: Q h,i = ω i ·Q h , and the predicted outlet water temperature after heating is: Thus, the error between the actual water temperature and the target temperature is: e t = T p - T 0 .

[0030] Further, the establishment of the bath heat exchange cycle optimization model in step S300 includes:

[0031] The heat exchange balance cycle control of the bath wastewater is realized through PID to obtain the output power P h of:

[0032]

[0033] where: K P represents the proportional gain coefficient of the PID controller, K i represents the integral gain coefficient of the PID controller, K d represents the differential gain coefficient of the PID controller.

[0034] According to the second aspect of the present invention, there is provided a bath wastewater purification and heat exchange balance recycling system for implementing the bath wastewater purification and heat exchange balance recycling method described above, including:

[0035] A primary bath wastewater purification module for collecting bath wastewater, filtering the wastewater and solid waste to obtain filtered wastewater, and performing disinfection treatment, oil decomposition treatment and pH value adjustment treatment on the filtered wastewater to obtain purified wastewater;

[0036] The advanced purification module for bath wastewater is used to obtain purified water and concentrated water after the purified wastewater is filtered by a microfiltration module and a reverse osmosis module. The purified water is sent to the bath heating equipment, and the concentrated water is sent to the filtered wastewater purification area for further purification and filtration.

[0037] The heat exchange balance recycling module is used to establish an optimized model for the bath heat exchange cycle based on the number of bathers, bath time, bath flow rate, and the real-time temperature of the purified water. According to this model, the hot water temperature in the heating inner tank of the bath heating equipment is adjusted in real time, so that the water temperature of the bath water used by the bathers within the bath time is maintained within the set bath range.

[0038] Further, the bath heating equipment includes: a constant temperature water tank, an inner heat exchange pipe, an outer heat exchange pipe, and a heating pipe. Among them,

[0039] A heating inner tank is provided in the constant temperature water tank, and a heating pipe for heating the purified water is installed in the heating inner tank.

[0040] The inner heat exchange pipe is coiled in the constant temperature water tank. The water inlet of the inner heat exchange pipe is connected to a purified water pump, which is used to send the purified water generated by re-filtering the purified wastewater into the inner heat exchange pipe. The water outlet of the inner heat exchange pipe is connected to the water inlet of the outer heat exchange pipe.

[0041] The water inlet of the heating inner tank of the constant temperature water tank is connected to a water inlet pipe, and the water outlet of the heating inner tank is connected to a drain pipe. A plurality of temperature sensors for detecting temperature are installed in the constant temperature water tank, and a pressure relief valve for adjusting the pressure of the heating inner tank and a liquid level gauge for measuring the liquid level height in the heating inner tank are provided.

[0042] Further, the outer heat exchange pipe is wound around the periphery of the constant temperature water tank, and the water outlet of the outer heat exchange pipe is used to output bath water.

[0043] The cold water on the outer layer of the outer heat exchange pipe absorbs the heat of the inner layer of water, increasing the initial temperature of the cold water before it flows into the heating inner tank of the constant temperature water tank.

[0044] Generally speaking, compared with the prior art, the above technical solutions conceived by the present invention can achieve the following beneficial effects:

[0045] 1. The method of the present invention establishes an optimized model for the bath heat exchange cycle based on the number of bathers, bath time, bath flow rate, and the real-time temperature of the purified water. According to this model, the hot water temperature in the heating inner tank of the bath heating equipment is adjusted in real time, so that the water temperature of the bath water used by the bathers within the bath time is maintained within the set bath range, realizing the integration of bath sewage purification and heat exchange recycling.

[0046] 2. The method of the present invention: After collecting the bath wastewater, the wastewater is filtered with solid waste to obtain filtered wastewater. After the filtered wastewater is subjected to sterilization treatment, oil decomposition treatment, and pH value adjustment treatment, purified wastewater is obtained. After the purified wastewater is filtered through a microfiltration module and a reverse osmosis module, purified water and concentrated water are obtained. Among them, the purified water is sent to the bath heating equipment, and the concentrated water is sent to the filtered wastewater purification area for further purification and filtration treatment, realizing the multi-stage purification treatment of bath wastewater.

[0047] 3. The method of the present invention: During the wastewater purification process, through precipitation, filtration, and sterilization, solid impurities and chemical pollutants are separated, and the wastewater heat is recovered in real time. Through PID, the heat exchange balance cycle control of the bath wastewater is realized, the output power of the bath heating equipment is obtained, and the hot water temperature in the heating inner tank of the bath heating equipment is adjusted in real time. Description of the Drawings

[0048] Figure 1 It is the bath working flow chart of the bath wastewater purification and recycling method of the embodiment of the present invention;

[0049] Figure 2 It is the schematic diagram of the system composition of the bath wastewater purification and recycling method of the embodiment of the present invention;

[0050] Figure 3 It is the schematic diagram of the structure of the bath heating equipment in the bath wastewater purification and recycling method of the embodiment of the present invention;

[0051] Figure 4 It is the change relationship diagram of the water temperature at the center of the heating inner tank and time in the embodiment of the present invention;

[0052] Figure 5 It is the change relationship diagram of the outlet water temperature and the number of bathers at the start of single-person bathing in the embodiment of the present invention;

[0053] Figure 6 It is the change relationship diagram of the outlet water temperature and the number of bathers at the end of single-person bathing in the embodiment of the present invention;

[0054] Figure 7 It is the change relationship diagram of the outlet water temperature difference and the number of bathers during single-person bathing in the embodiment of the present invention;

[0055] Figure 8 It is the change relationship diagram of the outlet water temperature and the number of bathers at the start of multi-person bathing in the embodiment of the present invention;

[0056] Figure 9 It is the change relationship diagram of the outlet water temperature and the number of bathers at the end of multi-person bathing in the embodiment of the present invention;

[0057] Figure 10 It is the change relationship diagram of the outlet water temperature difference and the number of bathers during multi-person bathing in the embodiment of the present invention.

[0058] In all the drawings, the same reference numerals denote the same technical features, specifically: 1. Constant temperature water tank; 2. Inner heat exchange tube; 3. 003; 4. Liquid level gauge; 5. Pressure relief valve; 8. Temperature sensor; 9. Heating tube; 10. Water inlet pipe; 11. Drain pipe; 12. Outer heat exchange tube. Specific embodiments

[0059] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present 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 only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0060] Embodiment 1

[0061] Refer to Figure 1 , in the embodiment of the present invention, a control method for purifying and recycling bath wastewater is provided, including the following steps:

[0062] S100: After collecting the bath wastewater, the wastewater is filtered from solid waste to obtain filtered wastewater. After the filtered wastewater is subjected to sterilization treatment, oil decomposition treatment and pH adjustment treatment, purified wastewater is obtained;

[0063] S200: After the purified wastewater is filtered through a microfiltration module and a reverse osmosis module, purified water and concentrated water are obtained. The purified water is sent to the bath heating equipment, and the concentrated water is sent to the filtered wastewater purification for further purification and filtration treatment;

[0064] In this embodiment, the method for collecting the wastewater further includes the following steps: The wastewater is filtered from solid waste through a hair filter, and the wastewater is filtered from oil and large particle impurities through a carbon fiber filter to obtain filtered wastewater, and the filtered wastewater is sent to the wastewater collection tank.

[0065] In this embodiment, the method for purifying the filtered wastewater further includes the following steps: The filtered wastewater in the wastewater collection tank is sterilized and the residual oil is decomposed through an ozone generator; The pH adjustment agent in the medicine box is sent to the wastewater collection tank through a dosing pump, and the pH value of the filtered wastewater in the wastewater collection tank is adjusted to the set pH value.

[0066] In this embodiment, the pH adjustment agent is oxalic acid or citric acid or dilute hydrochloric acid with a pH value of 1.

[0067] In this embodiment, the method for re-filtering purified wastewater further includes the following steps: When the water volume in the wastewater collection tank reaches the high liquid level of the wastewater collection tank and the water volume in the clean water tank is lower than the high liquid level of the clean water tank, the wastewater treatment pump sends the filtered wastewater in the wastewater collection tank to the microfiltration module and the reverse osmosis module in sequence for filtration treatment. The clean water discharged from the reverse osmosis module is sent into the clean water tank, and the clean water tank supplies water to the bathing heating equipment; the concentrated water discharged from the reverse osmosis module is sent back into the wastewater collection tank.

[0068] It should be noted that the microfiltration module is a microfiltration processor, and the reverse osmosis module is a reverse osmosis processor.

[0069] In this embodiment, the method for re-filtering purified wastewater further includes the following steps: When the water volume of the filtered wastewater in the wastewater collection tank reaches the low water level of the wastewater collection tank and the water level in the clean water tank reaches the high liquid level of the clean water tank, the wastewater treatment pump stops working, completing a single step of re-filtering purified wastewater.

[0070] Preferably, in this embodiment, before the wastewater treatment pump sends the filtered wastewater in the wastewater collection tank to the microfiltration module and the reverse osmosis module for filtration treatment, the backwash solenoid valve is first opened, so that the filtered wastewater first performs a backwash operation on the microfiltration module and the reverse osmosis module. The washing water generated by the backwash operation is sent into the sewage drain pipe; until the backwash operation time reaches the backwash duration.

[0071] In this embodiment, the method for planning the heating of bathing water further includes the following steps: Low liquid level, medium liquid level, and high liquid level are set in the clean water tank. When the water level in the clean water tank is lower than the low liquid level, the water replenishment solenoid valve is opened, and sanitary water is replenished into the clean water tank until the water level in the clean water tank reaches the medium liquid level and then the water replenishment stops; after the water replenishment ends, the hot water temperature in the heating inner tank of the bathing heating equipment is determined; and the water in the clean water tank is sterilized by an ultraviolet germicidal lamp.

[0072] The present invention also provides a control method for purifying and recycling bathing wastewater, which is applied to the method for purifying and recycling bathing wastewater. The control method for purifying and recycling bathing wastewater includes the following steps:

[0073] When the pH meter detects that the pH value of the filtered wastewater > 9, the pH dosing pump is started, so that the pH adjustment agent adjusts the pH value of the filtered wastewater to ≤ 8;

[0074] Wastewater collection: After collecting the bathing wastewater, the wastewater is filtered from solid waste to obtain filtered wastewater;

[0075] Purification of filtered wastewater: After performing sterilization treatment, oil decomposition treatment, and pH value adjustment treatment on the filtered wastewater, purified wastewater is obtained;

[0076] After the purified wastewater is filtered through the microfiltration module and the reverse osmosis module, the filtered water is obtained. When the turbidity of the filtered water ≤ 1 NTU, the filtered water is determined to be purified water and sent to the bath heating equipment; when the turbidity of the filtered water > 1 NTU, the filtered water is determined to be concentrated water, and the concentrated water is sent to the filtered wastewater purification step for further purification and filtration.

[0077] S300: Establish a bath heat exchange cycle optimization model based on the number of bathers, bath time, bath flow rate, and the real-time temperature of the purified water, and adjust the hot water temperature in the heating inner tank of the bath heating equipment in real time according to this model, so that the water temperature of the bath water used by the number of bathers within the bath time remains within the set bath range.

[0078] Further, the establishment of the bath heat exchange cycle optimization model in step S300 includes:

[0079] S301: Combining the actual situation of the bath scenario, dynamically predict the total heat demand Q for multiple people taking baths simultaneously T as:

[0080]

[0081] where: Q t is the water flow rate, N t is the number of bathers at time t, representing the scale of water use load, t s is the average bath time per person, c p is the specific heat capacity of water, T r 、T c are the target outlet water temperature and the cold water inlet temperature respectively, representing the temperature of the unheated cold water before entering the heating system or heat exchanger, Q indiv represents the heat of water used per person.

[0082] Further, the establishment of the bath heat exchange cycle optimization model in step S300 includes:

[0083] S302: During the wastewater purification process, after separating solid impurities and chemical pollutants through precipitation, filtration, and sterilization, recover the wastewater heat Q in real time w as:

[0084]

[0085] where: m t = N t ·Q t ·ρ, representing the wastewater mass, T w represents the wastewater temperature, depending on the user's drainage temperature, T a represents the ambient temperature.

[0086] Further, the establishment of the bath heat exchange cycle optimization model in step S300 includes:

[0087] S303: The latent heat and sensible heat recovered by the steam generated during the bathing process through the condensation device are respectively:

[0088]

[0089] Where: Q s is the heat recovered from the steam, and Q c is the sensible heat recovered from the condensed water. m s represents the mass of the steam, L represents the latent heat of vaporization of the steam, and T c represents the temperature of the condensed water;

[0090] Thus, the total waste heat recovery amount is obtained as: Q r = Q w + Q s + Q c .

[0091] Further, the establishment of the bath heat exchange cycle optimization model in step S300 includes:

[0092] S304: Based on the total heat demand and the total waste heat recovery amount of multiple people bathing simultaneously, a dynamic optimization model of the heat exchanger is established as:

[0093] Q i，in = Q w，i + Q s，i + Q h，i

[0094] Where: Q i，in is the input heat allocated to the i-th heat exchanger; Q w，i is the waste water heat allocated to the i-th heat exchanger, Q s，i is the steam heat allocated to the i-th heat exchanger, Q h，i is the sensible heat allocated to the i-th heat exchanger, and the output heat is: Q i，out = Q i，in ·η i , η i is the heat exchanger efficiency, then the heat exchanger load balance is:

[0095]

[0096] Where: ε is the threshold for restricting the fluctuation of the heat exchanger output heat.

[0097] Further, the establishment of the bath heat exchange cycle optimization model in step S300 includes:

[0098] S305: The total supplementary heat is: Q h = Q T - Qr , based on the supplementary heat Q h The heat allocated to each heat exchanger is established as: Q h,i = ω i ·Q h , and the predicted outlet water temperature after heating is: Thus, the error between the actual water temperature and the target temperature is obtained as: e t = T p - T 0 .

[0099] Furthermore, the establishment of the bath heat exchange cycle optimization model in step S300 includes:

[0100] The heat exchange balance cycle control of the bath wastewater is realized through PID to obtain the output power P of the bath heating equipment h which is:

[0101]

[0102] where: K P represents the proportional gain coefficient of the PID controller, K i represents the integral gain coefficient of the PID controller, K d represents the derivative gain coefficient of the PID controller.

[0103] Embodiment 2

[0104] As shown in FIGS. 2 and Figure 3 In this embodiment, a bath wastewater purification and heat exchange balance recycling system is provided for implementing the described bath wastewater purification and heat exchange balance recycling method, including:

[0105] A primary bath wastewater purification module for filtering the wastewater and solid waste after collecting the bath wastewater to obtain filtered wastewater, and performing disinfection treatment, oil decomposition treatment, and pH adjustment treatment on the filtered wastewater to obtain purified wastewater;

[0106] A deep bath wastewater purification module for filtering the purified wastewater through a microfiltration module and a reverse osmosis module to obtain purified water and concentrated water, where the purified water is sent to the bath heating equipment and the concentrated water is sent to the filtered wastewater purification for further purification and filtration treatment;

[0107] A heat exchange balance recycling module for establishing a bath heat exchange cycle optimization model based on the number of bathers, bath time, bath flow rate, and the real-time temperature of the purified water, and adjusting the hot water temperature in the heating inner tank of the bath heating equipment in real time according to this model, so that the bath water temperature used by the bathers within the bath time remains within the bath set range.

[0108] The bath heating device includes a constant temperature water tank 1, an internal heat exchange tube 2, an external heat exchange tube 12, and a heating tube 9. In the heating inner tank of the constant temperature water tank 1, there is a heating tube 9 for heating the purified water in the heating inner tank. An internal heat exchange tube 2 is also coiled in the constant temperature water tank 1. The water inlet of the internal heat exchange tube 2 is connected to a purified water pump, and the purified water pump is used to send the purified water generated by re-filtering the purified waste water into the internal heat exchange tube 2. The water outlet of the internal heat exchange tube 2 is connected to the water inlet of the external heat exchange tube 12. The external heat exchange tube 12 is wound around the periphery of the constant temperature water tank 1, and the bath water is sent out from the water outlet of the external heat exchange tube 12.

[0109] The water inlet of the heating inner tank of the constant temperature water tank 1 is connected to a water inlet pipe 10, and the water outlet of the heating inner tank is connected to a drain pipe 11. A plurality of temperature sensors 8 for detecting temperature are also installed in the heating inner tank. A pressure relief valve 5 for adjusting the pressure of the heating inner tank and a liquid level gauge 4 for measuring the liquid level height in the heating inner tank are installed on the constant temperature water tank 1. The inner and outer layers of water in the outer tube are in the same path in the inner tube of the inner tank. The temperature absorbed by the cold water in the outer layer of the outer tube increases the initial temperature heated by the inner tank. At the same time, the outer layer of water absorbs the heat of the inner layer of water, which also makes the bath water temperature not too hot, maintaining at around forty degrees Celsius, playing a role in preventing scalding.

[0110] Embodiment 3

[0111] As Figures 8 - 10 shown, in this embodiment, the bath heat exchange cycle optimization model is used to simulate and calculate the bath process of 20 people. The single-person bath time is set to 10 minutes, and the interval between two people is 5 minutes. In the bath state, as Figure 4 can be seen, after the cold water enters the external heat exchange tube 12, it absorbs the temperature of the hot water flowing reversely in the inner layer and gradually warms up to 46°C and enters the internal heat exchange tube 2 in the constant temperature water tank 1. The coiled tube descending along the internal heat exchange tube 2 absorbs the heat of the water in the constant temperature water tank 1 to about 73°C, and then the coiled tube ascending along the internal heat exchange tube 2 maintains a flow of 73°C to the inner layer of the external heat exchange tube 12. During the countercurrent process of the hot water in the inner layer of the external heat exchange tube 12 and the cold water in the outer layer of the external heat exchange tube 12, the temperature is gradually transferred to the cold water in the outer layer of the external heat exchange tube 12, making the cold water in the outer layer of the external heat exchange tube 12 warm up to 42°C, so that the bath water is about 42°C. It is realized by the countercurrent heat exchange of the sleeve and the heat exchange structure of the inner tank.

[0112] As Figure 4It can be seen that from t = 0 to 3 min, the water temperature at the center of the inner tank rapidly drops from 85°C to 71°C, which is related to the setting of the simulation initial conditions. In the calculation, it is set that at t = 0 min, the water in the pipe is all 20°C, and the water in the tank is all 85°C, and the heat flux is relatively large, so there is a sudden temperature drop. After t = 3 min, the temperature at the center of the inner tank shows a cycle of 15 min. Corresponding to the state of the water flow switch in the pipe, during the single-person bathing process, when the water in the pipe flows, the temperature in the tank gradually decreases, with an average decrease of about 2.32°C. When the water in the pipe does not flow during the interval after the bathing ends, the temperature in the tank gradually rises again, with an average increase of about 2.26°C. The water temperature in the tank is 69.84°C after the 20th person finishes bathing.

[0113] It can be seen from Figure 5 that the water temperature at the start of bathing for the first person is 43.28°C, the water temperature at the start of bathing for the 20th person is 42.47°C, and the average start-bathing temperature for 20 people is 42.65°C. The start-bathing temperature gradually decreases with the number of bathing people, and the rate of temperature decrease becomes smaller and smaller. The maximum temperature decrease is 0.38°C, and the minimum temperature decrease is 0°C.

[0114] It can be seen from Figure 6 that the water temperature at the end of bathing for the first person is 41.82°C, the water temperature at the end of bathing for the 20th person is 41.31°C, and the average start-bathing temperature for 20 people is 41.48°C. The end-bathing temperature also gradually decreases with the number of bathing people. The maximum temperature decrease is 0.08°C, and the minimum temperature decrease is 0°C. Figure 8 It shows the change of the outlet water temperature difference during the single-person bathing process with the number of bathing people. It can be seen from Figure 8 that except for the first person whose outlet water temperature difference is 1.46°C during the 10-min bathing process, the average outlet water temperature difference for the remaining 19 people during bathing is 1.15°C. Therefore, the outlet water temperature during the bathing process is relatively stable.

[0115] After the cold water enters from the outer layer of the external heat exchange sleeve, it absorbs the heat of the hot water flowing in the reverse direction in the inner layer and gradually warms up to 46°C and enters the inner heat exchange coil in the inner tank. Along the downward coil, it absorbs the heat of the water in the inner tank to about 73°C, and then flows along the upward coil at 73°C to the inner layer of the external heat exchange sleeve. During the process of countercurrent flow with the cold water in the outer layer, it gradually transfers the temperature to the cold water and finally reaches the outlet at a temperature of about 42°C.

[0116] In summary, when the heating tube 9 heats the water temperature in the inner tank of the constant temperature water tank 1 to be stable at 69.8°C - 73.3°C. During the whole process of 20 people taking a bath, the outlet water temperature in the pipe can be stable at 41.3°C - 43.4°C, the water temperature is comfortable, and bathing can be carried out without adjusting the mixing valve, avoiding the scalding problem caused by improper mixing of water. And the temperature fluctuation during single-person bathing is relatively small, about 1.15°C. Therefore, it can enable users to achieve a better bathing experience during the bathing process.

[0117] Those skilled in the art can easily understand that the above description is only a preferred embodiment of the present invention and is not used to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for purifying and recycling bathing wastewater with heat exchange balance, characterized in that: The following steps are involved: S100: After the bathing wastewater is collected, the wastewater and solid waste are filtered to obtain filtered wastewater, and the filtered wastewater is sterilized, decomposed, and treated to adjust the pH value to obtain purified wastewater; S200: After the purified wastewater is filtered through a microfiltration component and a reverse osmosis component, clean water and concentrated water are obtained, wherein the clean water is sent to a bathing heating device, and the concentrated water is sent to a filtered wastewater purification unit for further purification and filtering; S300: A bathing heat exchange cycle optimization model is established according to the number of bathers, bathing time, bathing flow rate and the real-time temperature of the purified water, and the temperature of the hot water in the heating tank of the bathing heating device is adjusted in real time according to the model, so that the temperature of the bathing water used by the number of bathers during the bathing time is maintained within the bathing setting range.

2. A method for purifying and recycling bathing wastewater with heat exchange balance according to claim 1, characterized in that: The step S300 of establishing a bath heat exchange cycle optimization model includes: S301: Based on the actual situation of the bathing scene, dynamically predict the total heat demand Q of multiple people bathing at the same time T for: Where: Q t is the water flow rate, N t is the number of bathers at time t, indicating the water load scale, t s is the average bathing time per person, c p is the specific heat capacity of water, T r 、T c are the target water outlet temperature and cold water inlet temperature, respectively, indicating the temperature of the unheated cold water before entering the heating system or heat exchanger, Q indiv Indicates the heat of water used by one person.

3. A method for purifying and recycling bathing wastewater with heat exchange balance according to claim 2, characterized in that: The step S300 of establishing a bath heat exchange cycle optimization model includes: S302: During the wastewater purification process, solid impurities and chemical pollutants are separated through sedimentation, filtration and sterilization, and wastewater heat Q is recovered in real time w for: Where: m t =N t Q t ·ρ, represents the wastewater quality, T w Indicates wastewater temperature, which depends on the user's discharge temperature, T a Indicates the ambient temperature.

4. A method for purifying and recycling bathing wastewater with heat exchange balance according to claim 3, characterized in that: The step S300 of establishing a bath heat exchange cycle optimization model includes: S303: The steam generated during the bathing process is recovered through a condensing device with latent heat and sensible heat respectively: Where: Q s is the steam recovery heat, Q c The heat is recovered from the sensible heat of condensed water. m s represents the mass of steam, L represents the latent heat of vaporization of steam, T c Represents the temperature of condensed water; The total waste heat recovery is: Q r =Q w +Q s +Q c .

5. A method for purifying and recycling bathing wastewater with heat exchange balance according to claim 4, characterized in that: The step S300 of establishing a bath heat exchange cycle optimization model includes: S304: Based on the total heat demand of multiple people bathing at the same time and the total waste heat recovery, a dynamic optimization model of the heat exchanger is established as follows: Q i，in =Q w，i +Q s，i +Q h，i Where: Q i，in is the input heat allocated to the i-th heat exchanger; Q w，i is the wastewater heat allocated to the i-th heat exchanger, Q s，i is the steam heat allocated to the i-th heat exchanger, Q h，i is the sensible heat allocated to the i-th heat exchanger, and the output heat is: Q i，out =Q i，in ·η i , η i is the heat exchanger efficiency, then the heat exchanger load balance is: Where: ε is the threshold for limiting the fluctuation of heat output of the heat exchanger.

6. A method for purifying and recycling bathing wastewater with heat exchange balance according to claim 5, characterized in that: The step S300 of establishing a bath heat exchange cycle optimization model includes: S305: Total supplementary heat is: Q h =Q T -Q r , based on the additional heat Q h The heat allocated to each heat exchanger is: Q h,i =ω i Q h , the predicted outlet water temperature after heating is: The error between the actual water temperature and the target temperature is: t =T p -T0.

7. A method for purifying and recycling bathing wastewater with heat exchange balance according to claim 6, characterized in that: The step S300 of establishing a bath heat exchange cycle optimization model includes: The heat exchange balance cycle control of the bath wastewater is realized through PID, and the output power P of the bath heating equipment is obtained. h for: Where: K P Represents the proportional gain coefficient of the PID controller, K i Indicates the integral gain coefficient of the PID controller, K d Represents the differential gain coefficient of the PID controller.

8. A bathing wastewater purification and heat exchange balance recycling system, characterized in that: A method for purifying and cyclically utilizing bathing wastewater as claimed in any one of claims 1 to 7, comprising: The primary purification module for bathing wastewater is used to filter the wastewater and solid waste after collecting the bathing wastewater to obtain filtered wastewater, and sterilize, decompose grease and adjust pH value of the filtered wastewater to obtain purified wastewater; The deep purification module for bathing wastewater is used to obtain clean water and concentrated water after filtering the purified wastewater through microfiltration components and reverse osmosis components. The clean water is sent to the bathing heating equipment, and the concentrated water is sent to the filtered wastewater purification for further purification and filtering. The heat exchange balance circulation module is used to establish a bathing heat exchange circulation optimization model according to the number of bathers, bathing time, bathing flow rate and the real-time temperature of the purified water, and to adjust the temperature of the hot water in the heating tank of the bathing heating equipment in real time according to the model, so that the temperature of the bathing water used by the number of bathers during the bathing time is maintained within the bathing set range.

9. A bathing wastewater purification and heat exchange balance recycling system according to claim 8, characterized in that: The bathing heating device comprises: a constant temperature water tank (1), an inner heat exchange tube (2), an outer heat exchange tube (12) and a heating tube (9); wherein: The constant temperature water tank (1) is provided with a heating liner, and a heating tube (9) for heating purified water is installed in the heating liner; The inner plate of the constant temperature water tank (1) is provided with an inner heat exchange tube (2), the water inlet of the inner heat exchange tube (2) is connected to a clean water pump, and the clean water pump is used to send clean water generated by re-filtering the purified waste water into the inner heat exchange tube (2); the water outlet of the inner heat exchange tube (2) is connected to the water inlet of the heat exchange outer tube (12); The water inlet of the heating inner tank of the thermostatic water tank (1) is connected to the water inlet pipe (10), and the water outlet of the heating inner tank is connected to the drain pipe (11); a plurality of temperature sensors (8) for detecting temperature are installed in the thermostatic water tank (1), and a pressure relief valve (5) for adjusting the pressure of the heating inner tank and a liquid level meter (4) for measuring the liquid level in the heating inner tank are provided.

10. A bathing wastewater purification and heat exchange balance recycling system according to claim 9, characterized in that: The heat exchange outer tube (12) is arranged around the periphery of the constant temperature water tank (1), and the water outlet of the heat exchange outer tube (12) is used to output bathing water; The outer layer of cold water in the heat exchange outer tube (12) absorbs the heat of the inner layer of water to increase the temperature of the cold water, and the initial temperature of the cold water before flowing into the constant temperature water tank (1) to heat the inner tank is increased.

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