Loading/Unloading Skids for Liquid Hydrocarbon

Control and Safety Functions

• Batch Control Function:
  The batch controller installed on the loading skid starts the loading sequence according to a predefined program upon receiving the loading start command. It opens the relevant valves while simultaneously collecting flow data from the flow meter. When the preset loading quantity is reached, the controller closes the relevant valves according to the predefined sequence.

• Flow Control Function:
  A flow control valve and mass flow meter are installed in the loading skid. Parameters such as the safe loading quantity, safe flow rate, and advance volume can be preset to accurately control the loading flow rate, reduce water hammer effects, improve loading accuracy, and meet the process and safety requirements of the loading operation.

• Temperature and Pressure Alarm Function:
  Pressure transmitters and temperature transmitters are installed on the loading skid pipeline to continuously monitor the temperature and pressure during the loading process. The control system will generate an alarm when the monitored temperature or pressure exceeds the preset limits.

• Position Detection Function:
  A loading arm parking/support stand can be optionally installed on the loading skid. An explosion-proof proximity switch is installed on the parking stand. After loading is completed, the loading arm must be returned to the parking stand to prevent accidental movement of the arm, which could damage the loading arm or nearby equipment.

• Grounding Monitoring Function:
  A static grounding monitoring controller is installed on the loading skid to continuously monitor the grounding resistance during loading. If inadequate grounding is detected, the system will generate an alarm and automatically shut off the loading control valve.

• Lightning Protection Design:
  Surge protection devices are installed on the communication, power supply, and signal lines connected to the loading skid, providing protection against lightning surges and helping prevent damage to the control system caused by accidental lightning strikes.

• Control and Interlocking Function:
  The batch controller controls the skid-mounted automatic valves according to the process requirements. It collects signals from the pressure transmitters, temperature transmitters, flow meter, static grounding monitoring system, and valve position indicators. All relevant parameters and status signals are centrally displayed on the batch controller, enabling integrated control and interlocking of the loading system.

• Communication Function:
  The loading skid supports standard RS-485/MODBUS or TCP/IP communication protocols and can transmit real-time loading flow, temperature, pressure, valve position, grounding status, and other relevant operating data to the DCS (Distributed Control System). The loading skid can therefore be monitored by the plant-wide control system and integrated into the plant's data management system.