Application of the hottest mass flowmeter in the f

  • Detail

Successful application of mass flowmeter in coking blast furnace gas flow measurement in Xintie plant

1 Introduction to st98 mass flowmeter:

st98 mass flowmeter is a thermal diffusion mass flowmeter for air and gas measurement applications. St98 consists of a flow element, a flow transmitter and a package. For small diameters, use plug-in flow elements. For pipeline sizes larger than 40mm, use plug-in flow elements. The process connection of flow elements can be threaded connection or flange connection

st98 flow transmitter accepts AC or DC input power supply, and the output signal can be set to a standard range current or voltage. An RS-232C i/o serial port provides a channel for setting, monitoring and troubleshooting the flowmeter with fc88 programmer of FCI or PC computer

working principle: the flow element of st98 uses the working principle of thermal diffusion. A low-power heater heats a resistance temperature detector (RTD). If you don't have time to visit the machine in our factory between the two RTDs, there will be a temperature difference, and the fluid flow will be taken away by the heat on the heated RTD, causing the temperature difference between the two RTDS to change in proportion. The flow transmitter of the flowmeter converts the temperature difference between RTDS into a scale output signal and an optional display value

(1) main parameters:

operating temperature: ambient temperature of control circuit (- ℃); Standard temperature of sensor (- ℃)

operating pressure: 7Mpa;

flow range: 0 23NMPS;

signal output: Ma, 700 Ω maximum load;, VDC 100k Ω minimum load

flow accuracy: ± 1%+0.5% full scale

input power supply: AC input: VAC, 50/60hz

dc input: vdc

2 blast furnace gas flow measurement status of old coking plant:

blast furnace gas flow of old coking plant is measured by orifice flowmeter. Orifice flowmeter is composed of throttling device and differential pressure transmitter. It is easy to block, freeze, leak, and heat tracing, which is easy to cause the aging of differential pressure transmitter devices. In some cases, isolation liquid needs to be added to the impulse pipe. Due to heat tracing or unstable process operation, the isolation liquid lines of positive and negative impulse pipes are often unequal, resulting in liquid column difference, which makes the flow indication inaccurate. All of the above will change the flow coefficient, reduce the measurement accuracy and increase the measurement error. In addition, it is not suitable to disassemble for maintenance during production. Cause the detection point to fail. Bring inconvenience to production

3 coking blast furnace gas flow measurement in Xintie plant:

plug in St type mass flowmeter is used for coking blast furnace gas flow measurement in Xintie plant. The advantages of the flowmeter: the measuring device is integrated with the transmission unit, and the stress and strain field of the whole component or parts can be analyzed by computer finite element analysis and other calculation methods, which completely solves the phenomenon of blockage, freezing and leakage. It should be easy to disassemble and overhaul without stopping production. Also, the measuring range is within the scope of the meter, which can be set at will. Maintenance free at ordinary times. The measurement accuracy is high and accurate. Mass flowmeter is a new generation of flow meter with flexible configuration, powerful function and high performance price ratio

4 installation and use of mass flowmeter

after the installation and use of St mass flowmeter, the process personnel reported that there was a large error between the displayed data and the operating experience data, and they communicated with the operators by carefully reading the instructions. The reasons are analyzed as follows:

1) during installation, a straight pipe section of at least 20 times the pipe diameter shall be reserved at the upstream of the flow element and a straight pipe section of 10 times the pipe diameter shall be reserved at the downstream to ensure accuracy

2) install the st98 type mass flow meter, pay attention to make the small plane marked with the flow arrow parallel to the flow direction of the process medium, and make the flow arrow point to the flow direction of the process medium

3) the installation inspection point shall be located at an angle of 45 degrees below the center line of the pipe

4) st98 mass flowmeter is marked with serial number near the small plane engraved with flow arrow, and the same number is also marked on the package of active electronic circuit board and electronic components. These numbers must match

5) the insertion depth of mass flowmeter is equal to 1/2 + 12.7 + pipe wall thickness of pipe inner diameter

6) there should be no water near the detection point, otherwise the temperature difference will affect, resulting in inaccurate measurement

after the transformation according to the above installation method, the mass flowmeter works stably and measures accurately, achieving the expected effect

5 cost analysis:

a st98 mass flowmeter is about 50000 yuan. A set of throttling device includes differential pressure transmitter, orifice plate, flange, impulse pipe and valve, but it also needs about 15000 yuan to enlarge foam granulator and protection box. And every year to repair and replace spare parts, calculate the installation cost plus spare parts cost, maintenance cost, and spend a lot every year. In the long run, it is cost-effective to use mass flowmeter

6 operation cost analysis:

coke oven heating is heated with blast furnace gas. Whether the blast furnace gas flow is accurate or not not not only optimizes the operation in the production process. And it plays a decisive role in reducing costs and improving economic benefits. Therefore, the application of st98 mass flowmeter saves money and effort, and it does bring many benefits to flow measurement. St98 mass flowmeter is used not only in blast furnace gas flow measurement, but also in coke oven gas flow measurement. This table is worth promoting

Copyright © 2011 JIN SHI