The BY-RO-25T reverse osmosis pure water equipment adopts the advanced technology uniquely developed by our company. The pretreatment adopts double pump high-flow backwashing and reserves compressed air scrubbing interface to ensure fast and thorough pre-filtration. The unique U.V sterilization pretreatment process effectively controls the microbial content of raw water, reduces the burden of RO membrane, and prolongs the service life of RO membrane. The reverse osmosis device adopts the world's most advanced polyamide composite membrane element and the high-pressure water pump.The performance is reliable and stable, the noise is low, and the reasonable selection is calculated by computer design software. The pressure gauge, flow meter and water inlet and water production conductivity meter and other instruments are monitored online, and the sound and light alarm and automatic shutdown are triggered when the water quality exceeds the standard.
The process flow can be divided into three parts: pretreatment system, reverse osmosis and reverse osmosis cleaning system, and post-treatment water supply system.
The function of the pretreatment system is to remove substances in the raw water that are harmful to the reverse osmosis membrane, and to prevent a series of situations such as reverse osmosis membrane scaling, blockage or organic contamination due to the continuous increase in ion concentration on the concentrated water side, concentration polarization on the surface of the reverse osmosis membrane, and the increase in suspended matter and organic matter concentration during the operation of the reverse osmosis system. In order to make the raw water meet the water inlet conditions for the normal operation of the RO equipment, it is very necessary to set up a pretreatment system to protect the equipment from operating normally and safely.
The reverse osmosis system is the main component of the process.
Reverse osmosis can adapt to raw water with various salt contents, especially in high-salinity water treatment projects, and can obtain good economic and technical benefits. In addition, the reverse osmosis method has a high desalination rate, high water recovery rate, stable operation, small footprint, and simple operation. It has now been widely used in various high-salinity water desalination projects.
1.1 Raw water pump
In order to ensure the constant flow and pressure of the system water supply, the manufacturer of the raw water booster pump of this system is the famous domestic brand water pump-Nanfang Special Pump Industry. The water pump is a maintenance-free mechanical seal pump with high efficiency, low noise, stable and reliable performance.
1.2 Quartz sand filter
The common method to further remove suspended matter in water is mechanical filtration. By passing the muddy water through the granular filter layer, the suspended matter in the water can be intercepted, and the outflow is clear water. The granular filter material filtration method is simple, and when the filter layer fails, it is easy to restore its filtration performance by backwashing. In order to enhance the backwashing effect, a double pump backwashing is specially set and a soda backwashing interface is reserved; the equipment backwashing is controlled by the equipment operation pressure difference. When the filter runs to the filter layer head loss is about 0.7kg/cm2 more than the clean filter layer, backwashing is carried out.
The multi-media filter is filled with high-quality quartz sand, three grading layers are loaded, the total height of the filter layer is 1200mm, and the normal operation filtration rate is 12.1m/h. It is mainly used to remove suspended matter, mud and granular impurities in water. The multi-media filter uses a Φ1600×3800 stainless steel pressure-resistant filter with a vertical structure and a pressure resistance of 6kg/cm2. The multi-media filter can process 23m3/hour of water; it can remove most of the suspended matter in the raw water and reduce the turbidity in the water.
Characteristics of multi-media filters:
a. Three graded filter materials can effectively remove large particles, colloids, and suspended matter.
b. Due to the unique uniform water distribution design, the filtration can achieve the maximum effect and greatly reduce the SDI value of the effluent.
c. The backwash device is designed with double pump strong flushing technology to enhance the backwashing effect. Make the backwashing process have strong capacity, low water consumption and short time.
d. Under normal circumstances, the backwashing cycle of a single filter is ≥12h.
1.3 Activated carbon filter
The activated carbon filter uses the adsorption capacity generated by the huge specific surface area of activated carbon to adsorb easily adsorbed substances in the water.
Activated carbon filters have a very high removal rate for free chlorine, organic matter, and color and odor in water. At the same time, they also have a high removal rate for some heavy metal ions that are easy to deposit. Therefore, they are filtered through activated carbon before the reverse osmosis equipment, which can play a very good protective role for the reverse osmosis equipment. In this scheme, it is used to remove organic matter and chloride in water, and at the same time, it can also reduce the content of untested heavy metal ions and avoid the deposition of heavy metal compounds on the surface of the reverse osmosis membrane. Excessive free chlorine is harmful to the RO membrane, so an activated carbon filter must be installed to reduce the concentration of free chlorine in the influent water.
The filter material of the activated carbon filter is made of high-quality coconut shell activated carbon, and quartz sand is used as the cushion layer. The normal operating filtration rate is 12.1m/h. A set of Φ1600×3800 stainless steel pressure-resistant filters is selected, with a vertical structure and a pressure resistance of 6kg/cm2. The activated carbon filter processes 23m3/h of water. When the filter runs to the filter layer, the head loss increases by about 0.5kg/cm2 compared with the clean filter layer, and backwashing is performed.
Characteristics of activated carbon filter:
a. It can effectively remove pollutants such as heavy metals, small molecular organic matter, pigments, odors, etc. that cannot be removed by the previous multi-media filter.
b. The unique uniform water distribution design makes the water distribution more uniform, which can achieve the maximum effect of adsorption filtration.
c. Under normal circumstances, the backwash cycle of a single filter is ≥24h.
1.4 Anti-scaling and dosing device
In order to avoid the deposition of insoluble salts, extend the service life of RO membranes, and increase water production, this design is equipped with an anti-scaling and dosing device, which mainly adds anti-scaling agents.
The anti-scaling mechanism of anti-scaling agents can be roughly divided into three processes: chelation, lattice distortion and dispersion; chelate Ca, Mg, Ba and other scale-forming ions, increase the saturation concentration of scale-forming ions in water, and can be adsorbed on crystal growth points, which can prevent the formation of hard scale through lattice distortion;
The dosing pump uses the American Milton Roy metering pump, the dosing amount is adjustable, and it is convenient and reliable to use.
1.5 5um security filter
The thickness of the reverse osmosis membrane is about 10 microns. If the particle size of the suspended matter is too large, it is very easy to scratch the desalination epidermis on the surface of the reverse osmosis membrane when the suspended matter passes through the membrane surface at high speed. The 5um precision filter is used to block substances larger than 5 microns. Through mechanical interception, the membrane is protected from damage, and the possibility of reverse osmosis membrane being blocked is also reduced.
In this system, the security filter is the last guarantee for removing suspended matter. This filter is also called a precision filter. This project uses a 304 stainless steel security filter with a filtration accuracy of 5um. The filter element uses a Φ63×1000 polypropylene cartridge filter element, and the filter medium is a polypropylene film filter element. This type of filter element has a large dirt holding capacity and a long service life. The replacement cycle: generally replaced once every 20-40 days.
The security filter can also judge the replacement time by the front and rear pressure difference. When the filter runs to the point where the filtration head loss increases by about 0.5kg/cm2 compared to the clean filter element, the filter element must be replaced.
1.6 Ultraviolet sterilizer
The ultraviolet sterilizer produces high-intensity ultraviolet light to irradiate water. When various bacteria, viruses, and other pathogens in the water are exposed to a certain dose of 254nm ultraviolet radiation, the DNA structure in their cells is damaged (breakage, or photochemical reaction), thereby killing bacteria and viruses in the water. The ultraviolet sterilizer is installed on the water inlet pipeline, which can effectively prevent the RO membrane from being contaminated by microorganisms to extend the service life of the RO membrane.
1.7 High-pressure pump
The high-pressure pump provides sufficient water inlet pressure for the reverse osmosis membrane assembly and maintains the normal operation of the reverse osmosis membrane. This system is equipped with a high-pressure pump produced by the internationally renowned Nanfang Pump Company, made of 304 stainless steel, with a flow rate of 38m3/h, a head of 132 meters, and a power consumption of 22kw.
The high-pressure water pump is equipped with a Danfoss/Mitsubishi variable frequency soft start controller. When the system starts and stops running, it plays a role of variable frequency soft start and soft stop, which can effectively prevent the water hammer impact on the reverse osmosis membrane assembly caused by excessive pressure of the high-pressure pump or too fast pressure relief when stopping.
1.8 Reverse Osmosis
According to the principle of reverse osmosis, it is a process of separating liquid mixtures by using the property of the reverse osmosis membrane that it can only selectively pass through solvents (usually water) and intercept ionic substances, using the static pressure difference on both sides of the membrane as the driving force, overcoming the osmotic pressure of the solvent, and allowing the solvent to pass through the reverse osmosis membrane. Membrane separation can remove harmful substances such as particles, colloids, organic impurities, microorganisms and 99% of dissolved salts in water to achieve the purpose of water desalination and purification. Reverse osmosis is driven by pressure difference. The inlet water is pressurized to a certain pressure by a high-pressure pump to enable the reverse osmosis process to proceed.
The reverse osmosis desalination part uses a first-stage two-stage reverse osmosis device. The reverse osmosis method can adapt to raw water of various salt contents, with high desalination rate, high recovery rate, stable operation, small footprint and easy operation. While desalting, most bacteria, colloids and large molecular weight organic matter are also removed.
The reverse osmosis device can realize the automation of process system operation through a programmable controller (PLC), and the system operation and membrane flushing do not require special management.
The reverse osmosis equipment produced by our company adopts the advanced technology, and uses computer design software and many years of practical work experience to design the best solution. The key components of the reverse osmosis device - reverse osmosis membrane components and high-pressure pumps. Their service life and operating reliability are better than those of domestic peers.
The reverse osmosis system also includes a cleaning system, which is mainly used to chemically clean the reverse osmosis system when the reverse osmosis membrane surface is contaminated. At the same time, it is used for flushing during normal operation to wash away some sediments on the membrane surface and restore the compacted membrane, restore the membrane performance, increase water production, and extend the life of the membrane.
1.9 Reverse Osmosis Equipment
Reverse osmosis membrane, high-pressure reverse osmosis membrane container and corresponding pipeline accessories. The reverse osmosis membrane is installed in the high-pressure reverse osmosis membrane container. The container is arranged according to the water quality of the raw water and the requirements of the reverse osmosis membrane itself, and is connected by pipelines as required. It is the main part of desalination treatment.
The reverse osmosis membrane uses the reverse osmosis membrane . The membrane model is BW30-400, the number is 25, and the average water output is 1.0m3/unit, which can avoid the water output drop caused by low water temperature in winter. The design service life of the membrane is 2 to 5 years. After 1 year, the desalination rate or water output may be lower than the design requirements.
The membrane shell uses a pressure-resistant glass fiber reinforced plastic pressure vessel, model 8040-5m, pressure resistance 300PSI, 5 cores, a total of 3 units. The RO component arrangement is one stage and two stages, and the equipment produces 25T/H of water.
1.10 Reverse Osmosis Cleaning Equipment
During the use of reverse osmosis membranes, due to the influence of various factors, there will inevitably be deposition on the membrane surface, but the degree is different. At the same time, since the reverse osmosis membrane is under high pressure during normal operation, the membrane will be compressed and deformed. If this continues for a long time, plastic deformation will occur, that is, the membrane is compacted and cannot be restored, resulting in a decrease in membrane performance. The cleaning of the flushing system is divided into physical flushing and chemical flushing. The function of physical flushing is to regularly flush the reverse osmosis membrane at high or low pressure to wash away the sediment on the membrane surface, and make full use of time to restore the compressed membrane and extend the service life of the membrane.
During the use of the reverse osmosis membrane, due to the influence of various factors, it is inevitable that there will be scaling or contamination. The chemical cleaning function of the cleaning system is that when the reverse osmosis membrane is scaled or contaminated and its performance decreases, it must be cleaned with corresponding chemicals according to the situation. During cleaning, the liquid is continuously sent into the container to clean the reverse osmosis membrane. The cleaning liquid after cleaning returns to the cleaning water tank and circulates continuously. In order to prevent the substances in the form of suspended matter that are washed from damaging the reverse osmosis membrane during circulation, a 5um precision filter is added to protect the reverse osmosis membrane from damage.
Cleaning filter
In this system, cleaning filter is to remove suspended solids generated during the cleaning process, to ensure that the membrane will not be contaminated again during the cleaning cycle, thus ensuring the cleaning effect; this project uses a microporous filter with a filtration accuracy of 5um, and the filter element uses 12 Φ63×1000 polypropylene cartridge filter elements, and the filter medium is a polypropylene film filter element. Generally, the RO system is cleaned once every six months, and 12 filter elements are used for each cleaning. After cleaning, the filter element is scrapped; 12 new filter elements are replaced for RO flushing and filtration, and the service life is one quarter.
1.11 Reverse Osmosis Membrane Group
a. Design Parameters
Raw Water Temperature: 250C;
First-stage Water Production: 25T/H
Production Water Conductivity: ≤30us/cm
b. Reverse Osmosis Process Calculation
Membrane Type: Polyamide Aromatic Reverse Osmosis Membrane, Membrane Model BW30-400, 25 Pieces, 5 3-core FRP Membrane Shells;
First-stage RO Membrane Configuration: First Section 1×5;
Second Section 2×5;
Recovery Rate: 65-75%;
c. Reverse Osmosis Equipment Configuration
d. In order to reduce the impact on the membrane when the high-pressure pump is started and stopped, the high-pressure pump adopts frequency conversion control by frequency converter.
e. Each membrane shell is equipped with a sampling port on the fresh water outlet pipe, which can easily monitor the membrane running in each membrane shell;
f. The concentrated water main pipe is equipped with a flow meter and a regulating valve, which can easily adjust the recovery rate;
g. It is controlled by a PLC programmable controller, which can automatically flush according to the set requirements and automatically resume normal working state after flushing;
h. It is equipped with an online water quality monitoring device to continuously monitor the conductivity of the outlet water;
i. In terms of pipeline configuration, the high-pressure part is a thick-walled 304 stainless steel pipeline, and the low-pressure part uses sanitary 304 stainless steel pipe valves, and the noise caused by excessive flow rate is fully considered. Therefore, all pipelines have been calculated and a reasonable pipe diameter is selected.
j. A manual cleaning system is set up for use when chemical cleaning is used, or when it is necessary to stop the operation for a long time, the reverse osmosis membrane is soaked with a reagent.
1.12 Post-treatment water supply system
The post-treatment water supply system includes:
Sterile water tank, ozone generator, ozone mixing tower, pure water supply pump, titanium rod filter
1.13 Sterile pure water tank
A sterile pure water tank made of SUS304 stainless steel is set after the reverse osmosis system (RO). The stainless steel pure water tank is high in strength, anti-pollution and aging-resistant, making it an ideal water storage tank for pure water. An imported liquid level controller is installed in the tank to form a fully automatic operation system. An air filter with an accuracy of 0.22um is installed on the top of the water tank to prevent negative pressure in the water tank and microbial contamination in the air. The water tank should be cleaned regularly.
1.14 Ozone generator
Ozone generator sterilization principle: Ozone sterilization belongs to biochemical oxidation reaction. Ozone oxidation decomposes the enzymes necessary for the oxidation of glucose in bacteria; it can also directly act on bacteria and viruses, destroy their cell walls and ribonucleic acid, decompose DNA, RNA, protein, lipids and polysaccharides and other macromolecular polymers, and destroy the bacterial metabolism, growth and reproduction process; it can also penetrate the cell membrane tissue, invade the cell membrane and act on the outer membrane lipoprotein and internal lipopolysaccharide, causing the cell to undergo permeability distortion, leading to cell dissolution and death, and dissolving and denaturing the genetic genes, parasitic bacteria, parasitic virus particles, bacteriophages, mycoplasmas and pyrogens (bacterial virus metabolites, endotoxins) in the dead bacteria. Looking at the principle of aseptic technology on microorganisms, it can be divided into three types: antibacterial, bactericidal and bacteriolytic. The use of ozone as a sterilizing agent belongs to bacteriolytic.
1.15 Ozone Mixing Tower
The ozone mixing tower is mainly used to mix ozone and sterilize and preserve the pure water produced by the reverse osmosis system, providing qualified water for the subsequent filling system. Ozone enters the bottom of the oxidation tower through a pipe, passes through the aerator, and emits micro bubbles through the microporous bubbler. The bubbles fully absorb the ozone during the rising process.
Dissolved in water. Water is scattered from the top of the ozone tower and flows away naturally from the top of the ozone tower. It ensures sufficient time for ozone to mix with water. This equipment is equipped with an imported ozone concentration monitor to monitor the ozone concentration in the water at any time, making the sterilization effect more thorough. The top is also equipped with tail gas discharge and overflow ports to ensure that excess ozone will not remain indoors. Affecting the production of staff. The overflow port ensures that after the water inside the mixing tower is full, the water will not flow back to the ozone generator and damage the ozone generator.
1.16 Titanium rod microporous filter
It is set to prevent the killed bacteria or particulate matter that may be contaminated by the water tank from entering the subsequent filling pipe network system. The filter element is made of titanium alloy microporous material with a filtration accuracy of 0.22um and is a cylindrical structure.
1.17 Automatic control instructions:
a. Low water level in the raw water tank stops the machine (float water level gauge signal);
b. Low pressure in front of the high-pressure pump stops the main machine, and attempts to re-pressure start 3 times within a certain period of time. If unsuccessful, manual reset is required (pressure switch signal);
c. Pure water tank (3 stainless steel water level gauge signals) controls the start and stop of the main machine, and the stop of the ozone tower water supply pump;
d. Ozone mixing tower (3 stainless steel water level gauge signals) controls the start and stop of the ozone tower water supply pump and the stop of the water supply pump, and the start and stop of the water supply pump filling machine;
e. Reverse osmosis flushing time 30-120S adjustable, interval flushing time adjustable options, flush once when full, flush once when the machine is turned on;
f. Double raw water pump backwashing, pure water tank full water switch;
g. Overload, overcurrent, overpressure, phase loss protection functions, etc.;
h. Process flow animation, can realize touch screen manual control of water pump, Chinese and English interface; cumulative working time; equipped with analog output flow meter.
It is determined that further design is needed.