Cylinders and gas cylinders: From industrial cornerstones to the pressure vessel revolution of the Hydrogen future

First, the nature and classification system of pressure vessels
As the core equipment of modern industry, the essence of cylinder and gas cylinder is to realize the safe storage and transportation of gas or liquid through the mechanical properties of metal or composite materials. The cylinder usually refers to the pressure vessel with carbon steel or alloy steel as the main body, while the gas cylinder is a broad concept covering a variety of materials such as aluminum alloy and carbon fiber composite materials. According to TSG23-2021 "Gas Cylinder Safety Technical Regulations", such containers must meet the strict standards of nominal pressure 0.2MPa to 70MPa and volume 0.4L to 3000L.
From the functional perspective, pressure vessels can be divided into four categories: industrial gas cylinders (such as oxygen cylinders, acetylene cylinders), liquefied petroleum gas cylinders (common 15kg household specifications), vehicle fuel cylinders (CNG/LNG storage cylinders), special gas containers (such as electronic grade high-purity gas cylinders). Among them, the automotive gas cylinder market is growing most rapidly, and the global demand for high-pressure hydrogen storage cylinders is expected to reach 230,000 in 2024, with a compound annual growth rate of 66%.
2. Technological breakthrough and standard evolution of manufacturing process
Modern cylinder manufacturing has formed a precision, intelligent production system. Taking liquefied petroleum gas cylinders as an example, their manufacturing needs to go through the following key processes:
1. Material refining ** : The use of sedated steel smelting technology to ensure the purity and ductility of the material. According to GB/T5842-2022, the main material of the cylinder should be smelted by open furnace or electric furnace, and the chemical composition is strictly controlled.
2.** Forming process ** : 316L stainless steel cylinder adopts a spinning forming technology, the wall thickness error is controlled within ±0.1mm, and the efficiency is increased by 30% compared with the traditional welding process.
3.** Welding and heat treatment ** : Pressure welds must be automatically welded, and the welding process must pass GB/T33209 assessment. The heat treatment process adopts continuous furnace temperature control to ensure the balance of material strength and toughness.
4.** Non-destructive testing ** : X-ray digital imaging technology to achieve seam defects 0.1mm detection, hydraulic test using external measurement method to determine the residual deformation rate, to ensure that each cylinder explosion safety factor is not less than 3.0.
In terms of international standards, China's integration with the ISO system has accelerated. For example, the design of type IV hydrogen storage cylinder needs to pass TSG23-2021 and ISO22991 dual certification, carbon fiber winding Angle, preload and other parameters need to meet international mutual recognition standards.
Third, the whole life cycle system of safety management
Safety management runs through the whole process of cylinder design, manufacture, use, inspection and scrapping. According to TSG23-2021, gas cylinders need to establish a unique traceability system, each cylinder needs to be marked with a 12-digit number, and the whole process information can be checked through the two-dimensional code.
** Key safety measures include ** :
1.** Regular inspection ** : Liquefied petroleum gas cylinders are inspected every 4 years, oxygen cylinders are inspected every 3 years, and the overdue failure rate should be controlled below 0.5%.
2.** Intelligent monitoring ** : Using pressure sensor and Internet of Things technology, real-time monitoring of cylinder pressure, temperature and other parameters. For example, Sinoma's hydrogen storage cylinder integrates intelligent valves to achieve automatic pressure relief from overpressure.
3.** Transportation and storage ** : Transport vehicles need to be equipped with anti-static devices, the height of the compartment is not less than 2/3 of the height of the cylinder when it is placed vertically, and the height of the stack is not more than 5 layers when it is placed horizontally.
4.** Scrap treatment ** : Scrap gas cylinders need to be treated destrucvely, such as flattening or cutting, to prevent illegal refurbishment. The Guangxi fire department has seized more than 100,000 "black gas cylinders" annually through steel seal identification, inspection ring tracing and other means.
4. Diversified expansion of application fields
Pressure vessels have been deeply integrated into various fields of the national economy:
1.** Industrial gas ** : The global industrial gas market has exceeded 150 billion US dollars, and steel cylinders, as the core storage and transportation carrier, support the needs of semiconductor, medical, food and other industries. For example, electronic grade high-purity gas cylinders are required to meet level 0.1ppb impurity control.
2.** Clean energy ** : Hydrogen storage cylinders have become a key bottleneck in the industry. The 70MPa Type IV hydrogen storage cylinder developed by Sinoma Technology adopts carbon fiber full winding technology, and the hydrogen storage density reaches 5.7wt%, which is 3 times higher than the traditional cylinder. Shijiazhuang Anruike's high-pressure hydrogen storage and transportation cylinder production line has an annual capacity of 100,000, promoting the commercialization of hydrogen energy heavy trucks.
3.** Livelihood protection ** : The number of liquefied petroleum gas cylinders in the country exceeds 150 million, and enterprises such as Hubei Dali Container realize the export capacity of 12,000 cylinders per day through intelligent transformation, covering more than 50 countries' markets.
V. Industry challenges and future trends
** The current industry faces three major challenges ** :
1.** Material bottleneck ** : carbon fiber relies on imports, 48K large tow product domestic production capacity is insufficient. After the 48K carbon fiber project of Shanghai Petrochemical is put into operation, the cost of hydrogen storage cylinders can be reduced by 40%.
2.** Security risks ** : Problems such as illegal filling and overdue inspection are prominent. In 2023, 70% of the national gas cylinder accidents involve "black gas cylinders", and the whole chain supervision needs to be strengthened.
3.** Standard lag ** : New products such as hydrogen storage cylinders lack unified technical specifications, and the revised version of TSG23-2024 has incorporated Type IV hydrogen storage cylinders into the supervision, promoting the standardized development of the industry.
** Future Development Direction ** :
1.** Lightweight ** : The proportion of carbon fiber composite cylinders will increase from 15% in 2024 to 40% in 2030, reducing the weight by 50% while improving the pressure bearing capacity.
2.** Intelligent ** : Integrated sensor and blockchain technology, to achieve the whole life cycle of gas cylinder data cannot be tampered with. For example, the smart cylinder of Beijing Tianhai Industry can query the filling record in real time through the mobile APP.
3.** Green manufacturing ** : Using laser welding, 3D printing and other processes, energy consumption is reduced by 30%. Cimc's hydrogen energy equipment base achieves carbon neutrality through photovoltaic power supply.
Conclusion
Cylinders and gas cylinders are not only the cornerstone of industrial civilization, but also the vanguard of the energy revolution. From traditional carbon steel to carbon fiber composite materials, from manual detection to intelligent traceability, the pressure vessel industry is experiencing unprecedented changes in a century. With the explosion of hydrogen energy industry and breakthroughs in material technology, future gas cylinders will be lighter, smarter and safer, providing solid support for the sustainable development of human society.