The Life Line for Liquid Chlorine Loading and Unloading -
Key Technologies and Compliance Requirements of Corrosion-Resistant Loading Arms
As a highly toxic and corrosive chemical liquid, the loading and unloading of liquid chlorine is the top priority of safety management in the chemical industry. Once a leak occurs, it will cause devastating damage to human life safety and the ecological environment. As the core equipment for liquid chlorine loading and unloading, the corrosion-resistant Loading Arm's technical reliability and compliance directly determine the safety factor of the entire operation link.
The primary technical core of the liquid chlorine loading arm is the selection of corrosion-resistant materials. Due to the strong corrosiveness of liquid chlorine to ordinary metal materials, conventional carbon steel or stainless steel cannot meet the long-term use requirements. Therefore, fluorine-lined materials or Hastelloy are generally used in the industry as the pipeline material in contact with the medium. The fluorine-lined pipeline lines the inner wall of the ordinary steel pipe with PTFE, which uses the excellent chemical inertness of PTFE to achieve perfect isolation of liquid chlorine and ensure the mechanical strength of the pipeline. In addition, key components such as rotary joints and seals are also made of corrosion-resistant materials, among which the seals are made of special fluororubber to ensure no leakage under the working pressure of 0.6-2.5MPa.
The redundant design of safety devices is another key requirement for liquid chlorine loading arms. According to the "Criteria for Determining Major Production Safety Accidents in Chemical and Hazardous Chemical Production and Operation Units", liquid chlorine filling must use a universal pipeline filling system (i.e., loading arm), and the use of hose connections is strictly prohibited. On this basis, the liquid chlorine loading arm is also equipped with dual emergency shutdown devices: one is an emergency breakaway valve, which automatically disconnects and seals when pulled by external force; the other is a remote emergency shutdown valve, which the operator can shut off the medium transmission at any time in the control room. At the same time, the equipment is also integrated with a leak detection sensor. Once chlorine leakage is detected, it will immediately trigger an acousto-optic alarm and link to start the spray absorption system to minimize the leakage hazard.
Compliance management is a core link in the use of liquid chlorine loading arms. After June 1, 2022, in accordance with the relevant regulations of the State Administration for Market Regulation, loading arms were officially included in the supervision of pressure components, and their manufacture, installation and inspection must comply with the requirements of the "Supervision and Inspection Rules for Pressure Pipes". Enterprises need to conduct comprehensive regular inspections on liquid chlorine loading arms, focusing on checking the thinning of pipeline wall thickness, the aging degree of seals, and the reliability of emergency shutdown devices. In past chlorine leakage accident cases, there have been situations where accidents occurred because the local severe thinning of the loading arm was not found in time. Such cases have sounded the alarm for the industry on compliance management.
With the continuous improvement of industry safety standards, liquid chlorine loading arms are developing towards intelligence and unmanned operation. By integrating technologies such as visual recognition and remote control, unmanned operation of the loading and unloading process is realized, reducing direct contact between personnel and highly toxic media. At the same time, the application of the predictive maintenance system can predict potential faults in advance by analyzing equipment operation data, ensuring that the equipment is always in a safe operating state and building a life defense line for liquid chlorine loading and unloading.
