Application of Intelligent magnetic flowmeter in Soda Ash Plant

Overview

The intelligent magnetic flowmeter is a fully intelligent magnetic flowmeter developed and developed with the most advanced technology at home and abroad. It is also specially designed with a Chinese LCD display with backlight and wide temperature. It has complete functions, intuitive operation and easy use, which can reduce installation, use and maintenance. trouble. While meeting on-site display, it can also output 4-20mA. current signal for recording, adjustment and control.

The flow measurement is not affected by changes in fluid density, viscosity, temperature, pressure and conductivity. There are no flow obstructions in the measurement pipeline, so there is no additional pressure loss, no moving parts in the measurement pipeline, and the sensor part has linings and electrodes. When the measured liquid is in contact, as long as the electrode and the lining material are selected reasonably, it can resist corrosion and abrasion, so the sensor has an extremely long life. The two-way measurement system can measure the forward flow and the reverse flow, so that the intelligent magnetic flowmeter can be used to measure acid, alkali, salt solution, coal water slurry, mineral pulp, mortar mortar, paper pulp, resin rubber latex synthetic fiber pulp and photosensitive Flow rate of gasification vapor and viscous substances of various suspended substances such as latex. It has been widely used in chemical, environmental protection, metallurgy, medical and papermaking water supply and drainage industries.

2. Principle and mechanism

The measurement principle of the intelligent magnetic flowmeter (shown in Figure 1) is based on Faraday’s law of electromagnetic induction. When the conductive liquid cuts the magnetic field lines in a magnetic field, the conductor generates an induced electromotive force. The induced electromotive force E is:

E=KBVD.(1)

Where: E is the induced electromotive force;

k-meter constant;

B-Magnetic induction intensity, T;

D-the inner diameter of the measuring tube, m;

V is the average flow velocity in the cross section of the pipe, and mSo sets the volumetric flow rate of the liquid as:

qv(m³/s),qv=πD²V/4, then E=(4kB/πD)qv=Kqv(2)

In the formula: K is the instrument constant, K=4KB/πD

The intelligent magnetic flowmeter is composed of two parts: a flow sensor and a converter. The sensor structure (shown in Figure 2), the measuring tube is equipped with excitation coils above and below, after the excitation current is passed, a magnetic field is generated to pass through the measuring tube, and a pair of electrodes are installed on the inner wall of the measuring tube to contact with the liquid, leading to the induced electric potential and sending it to the converter. The excitation current is provided by the converter.

Illustration of measurement principle of intelligent magnetic flowmeter

3. Application examples

The intelligent magnetic flowmeter has played a vital role in the 1.2 million t/year soda ash production plant of Qinghai Soda Industry. Qinghai Alkali Industry Co., Ltd. relies on the unique advantages of limestone, crude salt, coal and other advantageous resources in the Qaidam Basin to vigorously develop the salt chemical industry, and has formulated an overall plan for the annual output of 2.7 million tons of soda ash, 600,000 tons of caustic soda and 600,000 tons of PVC. At present, it is the largest single-scale production plant in the domestic soda ash industry using Solvay's soda method (ammonia soda method). Intelligent magnetic flowmeter was installed and used in the measurement of the carbonization liquid flow rate in the heavy alkali workshop. (The carbonization liquid is alkaline solution and highly corrosive). The diameter of the measuring tube was selected when the factory was selected: DN150 (DN is the nominal diameter ), measuring tube material: stainless steel, electrode material: titanium alloy, lining material: polytetrafluoroethylene, olefin fluid working temperature: <120°C. Vertical installation is selected during installation to ensure the first 5D of the straight pipe section (D is the pipeline (Inner diameter) 3D, high measurement accuracy, strong stability, reliable operation during use, to ensure the continuity and stability of production for the enterprise, not only to reduce the trouble of installation and maintenance of instrument maintenance personnel, but also to provide accurate cost accounting data. The on-site installation diagram is as follows:

4. Main advantages of intelligent magnetic flowmeter

①The sensor structure of the smart flowmeter is simple, there are no moving parts in the measuring tube, and there is no throttling element that hinders the flow of fluid. So when the fluid flows through the flowmeter, it will not cause any additional pressure loss. ②It can measure the flow of dirty medium, corrosive medium and suspended liquid-solid two-phase flow. This is because there are no parts obstructing the flow inside the measuring tube of the instrument, and only the inner lining and electrode of the measuring tube are in contact with the measured fluid. The material can be selected according to the nature of the measured fluid. ③The intelligent magnetic flowmeter is a volume flow measuring instrument. During the measurement, it is not affected by the temperature, viscosity, density and conductivity of the measured medium. Therefore, the magnetic flowmeter can be safely used to measure the flow of other conductive liquids only after being calibrated with water. ④4 Intelligent magnetic flowmeter has no mechanical inertia and is sensitive. The two-way measurement system can measure forward and reverse flow.