Method for identifying and eliminating ammonium salt deposition characteristics in pipe bundle of hydrogenation air cooler

A method for identifying and eliminating ammonium salt deposition characteristics in a pipe bundle of a hydrogenation air cooler, the method is characterized in having steps as follows:

• Step 1) entering a multi-phase flow medium containing hydrocarbons, oil, water into a hydrogenation air cooler inlet pipe box, the multi-phase medium flowing through a row of air cooler pipe bundles arranged in parallel to a hydrogenation air cooler outlet pipe box, wherein a frequency variable fan is installed to a bottom part of the air cooler pipe bundles, and the multi-phase flow medium in the air cooler pipe bundles flows by using the frequency variable fan to exchange heat and be cooled off;
• calibrating initial service states of the air cooler pipe bundles for the air cooler pipe bundles to draw a temperature initial calibration line of the respective air cooler pipe bundles on a same longitudinal cross-sectional surface;
• and by setting a surface temperature field of the air cooler pipe bundle at initial service as benchmark and setting a temperature difference of 10° C. as benchmark, drawing a plurality of equivalent temperature reference lines, and respectively setting N temperature initial calibration lines and the temperature equivalent reference lines as control benchmark lines;
• Step 2) adopting a position where the hydrogenation air cooler inlet pipe box and the air cooler pipe bundle are connected as an initial position of an axial length of the air cooler pipe bundle, and adopting a position where the hydrogenation air cooler outlet pipe box is located as an end position of the axial length of the air cooler pipe bundle, and setting the axial length of the air cooler pipe bundle as L;
• setting N sections at equal intervals along an axial direction in the air cooler pipe bundle as temperature information monitoring sections, setting one set of temperature transmitters at each of the temperature information monitoring sections, wherein each set of the temperature transmitters has M temperature transmitters, the M temperature transmitters in each set of the temperature transmitters are disposed at intervals along an outer wall of the air cooler pipe bundle in the temperature information monitoring section, an outer wall temperature of the air cooler pipe bundle is monitored in real time by using a total of N*M temperature transmitters in the N sections;
• setting a number of the air cooler pipe bundles as W, thereby making a total of the temperature transmitters provided in all of the air cooler pipe bundles N*M*W;
• Step 3) transmitting a temperature signal value monitored by each of the temperature transmitters to a single-chip microcontroller through an RS485 bus for data analysis and sorting;
• Step 4) performing temperature photographing on the hydrogenation air cooler pipe bundles regularly by using an infrared thermal imager located above the air cooler pipe bundles, and transmitting wirelessly a bundle temperature information image obtained through photographing to an industrial computer for data management, and, with the temperature difference of 10° C. as the benchmark, establishing a graph with a plurality of temperature equivalent actual lines through data processing;
• comparing the graph with the temperature equivalent actual lines with the temperature equivalent reference lines drawn in Step 1), and, in response to the graph of temperature equivalent actual lines of a corresponding air cooler pipe bundle monitored in real time being lower than the temperature equivalent reference lines by 6%, determining that there is a risk that ammonium salt is deposited under such working condition, and performing a next step to determine an exact temperature information monitoring section where ammonium salt deposits are located;
• Step 5) for each of the temperature information monitoring sections, performing calculation on a monitored temperature value of the temperature information monitoring section obtained by using the temperature transmitters as follows:
• T
• iN
• =
• (
• ∑
• u
• =
• 1
• M
• T
• iNu
• )
• /
• M
• wherein in the equation, Tin represents the monitored temperature value on an Nth temperature information monitoring surface of an ith air cooler bundle pipe, TiNu represents a temperature detected by an uth temperature transmitter on the Nth temperature information monitoring section of the ith air cooler bundle pipe, i represents a serial number of the air cooler pipe bundle, N represents a serial number of the temperature information monitoring section, and u represents a serial number of the temperature transmitter on the temperature information monitoring section;
• establishing an ammonium salt deposition risk identification model on whether ammonium salt is deposited in the pipe bundle of the hydrogenation air cooler as follows:
• e
• =
• (
• (
• ∑
• i
• =
• 1
• Q
• T
• iN
• )
• -
• Q
• ·
• min
• ⁡
• (
• T
• iN
• )
• (
• ∑
• i
• =
• 1
• Q
• T
• iN
• )
• )
• wherein Q represents a total number of the air cooler pipe bundles, min( ) indicates a minimum value to be obtained, and e represents a temperature deviation rate,
• in response to the temperature deviation rate e satisfying e≥5%, then there is a risk that ammonium salt is deposited in the Nth temperature information monitoring section of the ith air cooler pipe bundle, and a next step is carried out;
• in response to the temperature deviation rate e satisfying e<5%, then there is no risk that ammonium salt is deposited in the Nth temperature information monitoring section of the ith air cooler pipe bundle;
• Step 6) for the Nth temperature information monitoring cross-section of the ith air cooler pipe bundle having been determined that there is a risk that ammonium salt is deposited in Step 5), driving, by using a DC power source, a vehicle-mounted mechanism to move along sliding rails to above two semi-open clamps closest to the Nth temperature information monitoring section;
• respectively hanging down a cable with fixing and support structures and, at terminals, magnetic blocks from middle portions of two side grooves of the vehicle-mounted mechanism perpendicular to the air cooler pipe bundle;
• controlling to move the cable whose two terminals have the magnetic blocks to respectively magnetically attract and be connected with an electromagnet located in the semi-open clamp at two ends of a pitch segment where the Nth temperature information monitoring section is located, applying a frequency variable signal to a circuit in the pitch segment where the Nth temperature information monitoring section is located by using a frequency variable vibration damper having a control switch, and peeling off ammonium salt deposits on an inner wall of the air cooler pipe bundle by vibration of the pipe bundle through intermittent, high-frequent ON-OFF/opening-closing of the electromagnet and the magnetic blocks, and
• transmitting ultrasonic signals using an ultrasonic wave generator through an electronic control system to a region where ammonium salt is deposited in the pitch segment where the Nth temperature information monitoring section is located, wherein the ultrasonic signals drive block-like or sheet-like ammonium salt deposits to peel off from the inner wall of the pipe bundle, completing removal and regulation of the ammonium salt deposits when the temperature deviation rate e<3% is detected through monitoring in real-time, and returning the vehicle-mounted mechanism to the end position of the air cooler pipe bundle;
• and
• Step 7) based on steps in Step 1) to Step 6), monitoring in real time the temperature of each of the air cooler pipe bundles by using the industrial computer, and, intelligently looking for the temperature information monitoring section where ammonium salt is deposited in the air cooler pipe bundle and the pitch segment where the temperature information monitoring section is located according to the ammonium salt deposition risk identification model, the N temperature initial calibration lines, and the temperature equivalent reference lines, and driving the vehicle-mounted mechanism to remove the ammonium salt deposition characteristics of the air cooler pipe bundle and the corresponding pitch segment.