Hydrogen can be burned to generate heat, and after burning, it only produces water without forming greenhouse gases. Therefore, hydrogen energy is considered to be one of the cleanest energy sources so far. When hydrogen atoms combine with oxygen atoms, electrons move, forming current and generating electricity.
As a clean energy with great prospects, hydrogen energy is gaining more and more attention.
Main risks and corresponding measures when using hydrogen energy
When applying hydrogen energy reasonably and safely, what risks should we pay attention to and what corresponding measures are there?
1. Hydrogen and oxygen are mixed to form a highly explosive gas. The flammability range of hydrogen is very large, ranging from 4% to 78%. Therefore, special attention should be paid to ventilation and leak detection when transmitting and storing hydrogen.
2. The flame of hydrogen combustion is almost invisible to the naked eye, so a special flame sensor should be used to detect the flame of hydrogen combustion to prevent people from entering the combustion area by mistake.
3. Hydrogen is usually under high pressure during transportation/transmission. Common metals become brittle after contact with hydrogen. Hydrogen molecules are very small, and after long-term contact, they can leak from the cracks of brittle metals, so special materials are needed to store and transport hydrogen.
4. Liquid hydrogen has ultra-low temperatures. Once it leaks and contacts the skin, or people inhale cold liquid hydrogen vapor, it will cause frostbite, suffocation, and even death in the lungs.
The mechanical safety standards that can be referred to in the use of hydrogen energy are:
EN ISO 12100: General principles of safety design – risk assessment and risk reduction
EN ISO 13849: Evaluation and verification of safety functions, safety performance level (PL)
EN IEC 62061: Safety-related parts of control systems, safety integrity level (SIL)
In addition, users need to refer to the industrial information security standard-IEC 62443 to prevent illegal personnel/illegal behavior from causing damage to machinery and the environment.
A perfect combination of mechanical safety and information security protection solution
Pilz can provide a complete safety protection solution for hydrogen energy applications. At the mechanical safety level, safety control products-such as programmable safety modules PNOZmulti or safety PLC-PSS 4000 can be used for safety monitoring. At the industrial information security level, safety bridges and I.A.M related products can be used for safety protection.
Take the hydrogen refueling station as an example: each hydrogen refueling gun and the corresponding vehicle refueling port use a paired PSENcode safety coding switch to ensure the correctness between the hydrogen refueling gun and the refueling port. All safety-related sensors and safety valves on site are monitored by PNOZmulti or PSS 4000. The personnel operations of the entire hydrogen refueling station are centrally managed by the I.A.M industrial authority system. Each equipment operator is equipped with a PITreader authority personal electronic key. Each person can only perform related operations under his or her own authority. Not only that, each step of the operation will be recorded in the I.A.M industrial authority system. In this way, the mechanical safety and information security protection of the hydrogen refueling station are fully covered.
High voltage and current monitoring in the hydrogen production process
The high voltage and high current in the hydrogen production process require safety monitoring. PILZ can provide safety transmitters to achieve safe monitoring of AC and DC. For example, the HVT 300-DX safety transmitter can achieve safety monitoring of up to 1000V AC and DC, and the HVT 400-DX safety transmitter can achieve safety monitoring of up to 1500V AC and DC. The safety level of a single safety transmitter can reach SIL2, and the safety level of two matching transmitters can reach SIL3.
Safety control of combustion applications in the hydrogen use process
For the combustion applications involved in the hydrogen use process, PILZ’s programmable safety module PNOZmulti and safety PLC–PSS 4000 can provide TUV-certified combustion control software function blocks, which are convenient for users to directly call when writing safety control programs, and can easily achieve combustion control.
