Abstract: A method for predicting, regulating and controlling a wear characteristic of a flow channel in a valve. The method comprises: pasting an aluminum sheet in a valve core, and testing a wear rate; regulating inlet pressure, and obtaining distribution characteristics of a pressure field and a velocity field; establishing an association relationship between the wear rate and pressure and a flow velocity; increasing the inlet pressure, and drawing a discrete data curve and a continuous curve; obtaining a discrete data change curve and a continuous curve of the wear rate along with an opening degree of the valve core; obtaining an association relationship graph between the wear rate of the aluminum sheet and the inlet pressure and the opening degree of the valve core; and performing comparison and determination on a real-time wear rate actual value of the aluminum sheet and a critical wear rate value.

Abstract: Disclosed is a method for identifying and eliminating ammonium salt deposition characteristics in a pipe of a hydrogenation air cooler. A multiphase flow medium enters an inlet pipe box of a hydrogenation air cooler; cross sections and temperature transmitters are arranged on a pipe bundle of the air cooler in the axial direction; a temperature signal value is monitored and transmitted to a single-chip microcomputer for analysis; an infrared thermal imager performs photographing, and transmits data to determine that an ammonium salt deposition risk is present under this working condition; a monitored temperature value is calculated, an ammonium salt deposition risk identification model is established, and ammonium salt deposits are peeled off from the inner wall of the pipe bundle of the air cooler by means of vibration of the pipe bundle caused by the intermittent frequent switching-on/switching-off of an electromagnet and a magnetic block, and ultrasonic signals.

Abstract: The present disclosure relates to the field of electric power system, and more particularly to a topology of a series-connected MMC with a small number of modules, where the topology is composed of a three-phase bridge circuit, half-bridge valve strings, a three-phase filter inductor, and a three-phase grid frequency transformer. The topology of a series-connected MMC with a small number of modules in the present disclosure needs only two half-bridge valve strings, thus greatly reducing the number of the submodules as compared with the conventional MMC structure. When achieving the same high DC voltage output, the present disclosure can improve the power density of the MMC, realize stable three-phase AC output voltage, and further achieve balance of capacitor voltages in the two half-bridge valve strings.

Abstract: The present disclosure relates to the field of electric power system, and more particularly to a topology of a series-connected MMC with a small number of modules, where the topology is composed of a three-phase bridge circuit, half-bridge valve strings, a three-phase filter inductor, and a three-phase grid frequency transformer. The topology of a series-connected MMC with a small number of modules in the present disclosure needs only two half-bridge valve strings, thus greatly reducing the number of the submodules as compared with the conventional MMC structure. When achieving the same high DC voltage output, the present disclosure can improve the power density of the MMC, realize stable three-phase AC output voltage, and further achieve balance of capacitor voltages in the two half-bridge valve strings.

Abstract: A water injection method for a PID control-based adaptive intelligent water injection system is provided. The system includes a water injection portion, a power portion, a control portion, and a measurement and transmission portion. The water injection portion includes a hydrogenation reactor, heat exchangers, air coolers, and a separation tank. The power portion includes a motor and a water pump. The control portion includes a console and a bus. Temperature, pressure and flow velocity transmitters are additionally arranged at each of inlet and outlet pipes of various heat exchangers, and water injection points are disposed. Temperature, pressure and flow velocity signals of the inlet and outlet pipes of heat exchange devices are monitored, and the console performs error analysis on the three signals and uses a PID control algorithm to control the adjustment valve to alter the valve opening degree to adjust the water injection amount in real time.