Online concentration detection system using differential pressure method

Thread Content

The online concentration detection system utilizes soft sensing technology (for which four **patents have been granted) to extract the primary signals detected by conventional instruments (differential pressure transmitters, thermal resistors), and to build models in order to obtain the parameters required for real-time online detection. Timely responses to the production status during the manufacturing process provide reliable production data to guide operators on site or related equipment in carrying out preemptive control, thereby reducing the rate of defective products, improving product quality, and lowering energy consumption. It also reduces the number of laboratory tests, saves reagents, protects the environment, and improves work efficiency. According to the laws of fluid mechanics, when a fluid flows through a vertical pipe, the pressure difference between any two measurement points consists of two components: the static pressure difference and the frictional resistance. The static pressure difference, with the positions of the two measurement points remaining constant, depends on the concentration (density) of the fluid. To accurately obtain the concentration information of the medium from the differential pressure output signal, it is necessary to remove the frictional resistance signal from the measured differential pressure signal. In addition, errors caused by changes in the dielectric temperature and ambient temperature will also be compensated for. Through detailed mechanism analysis and taking into account the operating characteristics of specific reaction vessels, this online concentration detection system performs real-time measurement of concentration by establishing a nonlinear model for non-Newtonian fluids. The model requires only three types of hardware (introducing additional parameters has little impact on measurement accuracy and can be ignored): (1) differential pressure, a parameter that represents the specific gravity at a fixed height along the pipeline ； (2) Material temperature: The effect of temperature on concentration also exhibits a highly nonlinear relationship, necessitating compensatory correction. (3) Ambient temperature: The ambient temperature affects the thermal expansion and contraction of the capillary in the differential pressure transmitter, and compensation adjustment is also necessary. Experts, may I ask what method you use to measure viscosity (degree of polymerization)? Feel free to discuss and exchange ideas!