I. System Overview In the oil depot and various petrochemical units, loading operations are very busy. In order to improve the loading accuracy and efficiency, reduce the loss, and reduce the labor intensity of workers, it is necessary to use automated loading. The quantitative loading control system was developed to achieve the above objectives. It integrates computer control technology, network technology, and communication technology to achieve distributed control and centralized management functions for loading vehicles.
Second, the function of the system The automated loading mainly realizes several functions: quantitative loading control, security assurance, operation management, and sales management.
(1) Quantitative loading control: The valve of the quantitative loading control program control valve is switched, the flow rate of the flow meter is collected and temperature compensation is performed, and the predetermined amount of closing valve is reached.
(2) Safety guarantee: The quantitative loading controller detects the overflow level switch action (meaning that the tank is abnormally full) and closes the valve immediately. It detects the antistatic grounding switch action (meaning that the antistatic grounding is disconnected) and closes the valve immediately.
(3) Operation management and sales management are implemented by business computers. Truck loading is the gateway to sales. Therefore, business computers are connected to high-precision weighbridges in addition to communication with the quantitative loading control units.
As the accuracy of electronic truck scales (0.03%) is much higher than the national commercial measurement standard (0.35%), positive deviations (such as 0.25%) can be set at the operation stations, and under the premise that the oil products sold to users are not excessively high, Get benefits for the company. This measurement is very significant.
Under normal circumstances, the flow meter is controlled by the main controller of the meter and the main weighbridge is measured. Therefore, the flow meter can use a relatively low-cost and relatively inexpensive volumetric flow meter, which greatly reduces the equipment cost. At the same time, the ultra-high precision of the ground balance can be used to carry out on-line calibration of the flowmeters on each crane position, so that low-cost general flowmeters can operate under high-precision conditions. When the control machine fails, because the flowmeter is calibrated to a higher degree of accuracy, using the on-site quantitative control instrument within a certain range can not only guarantee the quantitative loading, but also satisfy the measurement requirements and improve the redundancy of the system. There is a real-time database in the business station, through which real-time statistics can be generated and various sales reports can be generated. This has great benefits for strengthening sales management, improving management levels and sales effectiveness, and preventing various types of errors.
The business station not only completes the sales management directly related to loading, but also monitors the site in real time. The entire management process can be basically divided into three steps: billing, loading, and settlement.
(1) Billing The business must be reviewed before loading. The operator registers the reasonable business. When registering the business, the customer name, product name specification, quantity, price and other data must be determined. Each business corresponds to a business number. The business number can be entered on the quantitative loading control instrument. If an electronic scale is used as the final measurement tool, empty cars must also be weighed to obtain the weight of the empty car. The result of the invoicing is to generate a voucher for delivery to the site called a bill of lading. After the business is set up successfully, the business can be directly downloaded to the designated quantitative loading control instrument, or waiting for the business request of the quantitative loading control instrument.
(2) The real-time monitoring program of the loading business machine on the site runs in the background. If necessary, it can be displayed in a graphic or textual manner through windows such as "full-view map" and "single-crane bitmap" so that the business (operator) can Comprehensive monitoring of the loading conditions at the site. At the same time, the field instrument can be operated in a specific window. These operations include setting various parameters, on-line and off-line detection and control, prohibiting or allowing local settings, and emergency stop operations.
(3) Settlement and settlement are based on the measurement result and fill in the data items such as the actual volume in the business order, and the result will be the basis for generating the invoice as the delivery result. To perform the settlement operation, the measurement result must first be obtained through the actual required measurement method. After the loading is completed, the business machine automatically obtains the flowmeter reading through the quantitative loading control instrument, and the electronic scale reading must be obtained through the confirmation of the operator.
If a high-precision flowmeter is used in the system and a parameter such as “closed valve advance†is reasonably defined, it can be considered that the actual installation amount is equal to the pre-release amount and no settlement operation is necessary.
Third, loading monitoring screen