In order to meet the discharge standard of water pollution prevention and control law, the wastewater outfall shall be provided with a cumulative type of flow measuring device to monitor the discharge water volume.
Wastewater Treatment Plant schematic diagram:
Wastewater treatment equipment Schematic diagram:
In the papermaking process, pulping and the various processes will produce a lot of wastewater, its physical properties, and concentrations of organic pollutants vary.
Re-recover and treat wastewater before it is discharged into the sewer, will reduce the content of pollutants in industrial wastewater, and not easy to have a rancid smell, normally use electromagnetic flowmeter to do to flow monitoring and planning.
Since the electromagnetic flowmeter can only measure the flow of liquid with conductivity, the conductivity of the fluid medium needs to reach the measurement requirements. Therefore, to confirm whether the fluid is conductive, you can use a standard multimeter to test, first set the multimeter to the measured resistance value mode, and put the probe into the fluid, even if the pointer of the multimeter moves slightly to zero during the test, indicates that there is electricity flowing inside the fluid.
Wastewater treatment Schematic diagram:
There are three main sources of papermaking wastewater：pulping waste liquid (black liquor ), middle water, paper machine whitewater, in the pulping and papermaking process, the discharged wastewater contains BOD (Biochemical Oxygen Demand) Remark 1 and SS (suspended matter) Remark 2 concentration very high, and contains a lot of chemical liquid and impurities. In the pulping stage, the Dissolved item of a large amount of plant fibers enters the water under the action of temperature, pressure, and chemicals, make the concentration of pollutants in pulping wastewater very high. Pulping paper production generally pulp, pulp washing, bleaching and papermaking steps consisting, every 1 ton of pulp produced will produce 60-100 m3 of wastewater.
In addition, waste gas is also produced in the papermaking process, such as: under anaerobic conditions, it will produce a malodorous gas - hydrogen sulfide, or in the process of pulp bleaching will also produce chemicals such as dioxin, so the air pollution control equipment is treated by a wet or semi-dry washing facility, and sent the generated sewage to the wastewater treatment system.
Remark 1：Biological oxygen demand (often written as BOD), refers to under fixed conditions, microbial decomposition biodegradable organic matter in water biochemical reactions carried out Number of dissolved oxygen consumed in the process of, in mg/liter or percentages, ppm represents.
Remark 2：Suspended solids, refers to solid matter suspended in water, including inorganic substances, organic matter, and mud sand, clay, microorganisms, etc. that are insoluble in water.
Wastewater treatment equipment reasons for using the FEM06 electromagnetic flowmeter, mainly because the flow meter sensor can be directly connected to the pipeline, at this time, it should be noted that the diameter and the pipe size must be consistent, detection element due to unobstructed flow inside the catheter during the measurement, therefore, we could ensure undisturbed during the measurement to avoid pressure loss.
Because it is used in measuring the volume flow rate, and therefore can be used to measure other types of conductive fluid, without further setting, it can save a lot of time to repeat the operation. There are no moving parts in the measuring pipe, also select the appropriate lining and electrode, reach wear and corrosion resistance, the combination of the above features, the electromagnetic flowmeter is suitable for measuring solid and liquid two-phase media. Example: acid, alkali, salt solution, mud with suspended soil, solid particles, fiber or viscous, etc, high conductivity medium, therefore, it is very suitable for wastewater flow monitoring as a product for flow monitoring, the food industry, pharmaceutical, and other industries often use electromagnetic flowmeter to do the monitoring and planning of wastewater flow.
Precautions of electromagnetic flowmeter Schematic diagram:
The needs to confirm the installation distance before installation. The conventional straight pipe section requirement is 5D behind the front 10D.There are different requirements for the case of bends and valves. pipe flange welding Install the flowmeter after completion.
Measuring the fluid in the pipeline must be full. The plug-in electromagnetic flowmeter cannot be tilted up to 15°.
It is recommended that the installation position be at the rear end of the pump outlet to avoid the bubble stay. Do not install at the inlet front to avoid negative pressure inside the pipe. It is recommended to install a shut-off valve downstream.
In order to ensure the stability of the flowmeter, reliable grounding to avoid interference, should be avoided in the vicinity of electrical appliances that are prone to magnetic field interference, and to avoid vibration of the pipeline, plastic pipelines must be grounded.
Quote: eYc FAQ Precautions of electromagnetic flowmeter
The electromagnetic Flowmeter uses Faraday's Law of electromagnetic induction to measure the process flow, application of the principle of electromagnetic induction measurements conductive fluid/flow, excitation current provided via the transmitter, generating a magnetic field passing through the measuring tube after power, the electrode is placed on the inner wall of the measuring tube to be in contact with the liquid, and the induced voltage is transmitted to the conveyor.
Principle of electromagnetic flowmeter:
E = kBDv、E = K x B x V x D、V = E/kBD
V=Velocity of conductor、k=Proportionality constant、E=Induced voltage、B=Magnetic field strength
D=Length of conductor
Suitable for measuring conductive liquid inside pipes, wastewater, highly corrosive and abrasive liquids the high precision measurement, features are no pressure loss, longevity, low power consumption, can be unaffected by fluid density, temperature, viscosity, pressure or conductivity, high accuracy of ±0.5% of reading, the product has the advantage of independence.
Connect to the PC for monitoring and planning via 4 ... 20 mA or RS-485. LCD screen operation interface can display flow, percentage and other functions, the big diameter is suitable for drainage system, the small and medium diameter is often used for high viscosity, highly corrosive and difficult to measure liquid, applicable to chemical plant related liquids, mining; small diameter is more commonly used in pharmaceutical factories, food industry, bioengineering and other places with environmental health requirements.
Part of the content quote: Water Pollution Prevention and Control Act
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