Differences in Hydrogen Compressor Maintenance and Decommissioning Across Industries

Hydrogen compressor maintenance involves the two highest-risk phases in the equipment’s entire lifecycle: maintenance and decommissioning. Unlike routine inspections and oil analysis, these two phases require the equipment to be thoroughly disassembled or permanently removed from the system; operational errors can directly lead to hydrogen leaks and explosions. ANZIGA’s guidelines for gaseous hydrogen installations explicitly stipulate that all flammable gas systems must be purged with nitrogen before air is introduced, and that air must be prevented from entering when starting up hydrogen compressors, as air mixed with hydrogen forms an explosive mixture. While this principle applies universally across all industries, specific operational standards vary significantly.

The chlor-alkali industry presents a particularly unique set of circumstances. Hydrogen compressors, chlorine compressors, HCl furnaces, and graphite heat exchangers constitute a highly specialized combination of equipment in the chlor-alkali industry. The outlet of the hydrogen compressor is equipped with a high-pressure alarm and an automatic pressure-relief valve; the hydrogen system must also be fitted with intermittent nitrogen purging lines for startup and shutdown procedures. In the event of a chlorine compressor failure, an interlock must shut down the rectifier transformer to stop power supply to the electrolysis cells. Therefore, prior to maintenance or dismantling, all equipment in this system must be shut down, and system isolation and purging must be performed in a coordinated manner; hydrogen compressor maintenance cannot be scheduled as an isolated operation.

Industry Differences in Hydrogen Compressor Maintenance

In the petrochemical industry, hydrogen compressor maintenance primarily involves major overhauls, with the core focus on addressing wear caused by continuous operation. When Burckhardt Compression repaired the hydrogen compressors in the hydrocracking unit at the IOCL Mathura Refinery in India, the small-end bushings of the third-stage connecting rods repeatedly seized, preventing the compressors from restarting. The maintenance team repaired and modified the small-end bore of the crosshead and the large- and small-end bores of the connecting rods. The cost of the repaired components was only 40% of that of new parts, while the mean time between failures was extended. Reciprocating compressor overhauls require sequential disassembly—starting with the valves, cylinder head, crosshead, piston, connecting rods, and crankshaft—with key control points being the precise measurement of the piston-to-cylinder liner clearance and the roundness and cylindricity of the crankshaft journals.

Hydrogen compressor repairs at hydrogen refueling stations focus on diaphragm compressors. A study based on actual operating data indicates that diaphragm compressor failures are primarily caused by cyclic fatigue and hydraulic system abnormalities, with frequent start-stop cycles accelerating diaphragm rupture. During repairs, hydraulic oil must first be drained back into the crankcase before disassembling the cylinder block and diaphragm chamber to replace the diaphragm and retighten the assembly. Imported equipment often faces challenges due to a lack of specialized tools and technical documentation.

Hydrogen compressor maintenance in the electronics and semiconductor industries is subject to extremely stringent cleanliness requirements. Maintenance must be performed in a cleanroom environment, and all materials of components in contact with hydrogen must be carefully selected to prevent outgassing contamination. Post-maintenance leak rate verification must achieve a level of 10⁻⁹ Pa•m³/s. Maintenance in hydrogen metallurgy focuses on restoring the precision of heavy machinery. In hydrogen DRI plants, the seal integrity of hydrogen compressors is a critical maintenance item; dry gas seals typically last 25,000 to 35,000 operating hours under clean hydrogen DRI conditions. Seal surfaces are often inspected for microscopic cracks using dye penetrant testing, and bolts must be tightened in stages following a diagonal sequence.

Industry Differences in Hydrogen Compressor Removal

The core objective of hydrogen compressor removal is to achieve complete isolation of equipment and systems and ensure environmentally sound disposal, all under conditions of absolute safety. EIGA Doc 137/20 states that hydrogen facilities largely employ a modular design; after removal, each independent unit can be removed as a whole and evaluated for potential reuse. Equipment that cannot be reused should be dismantled, sorted for recycling, and the remaining parts disposed of in compliance with waste management regulations.

Hydrogen compressor removal at hydrogen refueling stations is directly governed by GB 50516. Hydrogen storage pressure vessels, hydrogen compressors, and piping must be purged and purged with nitrogen of a purity of at least 99.2% prior to initial operation, before hot work during maintenance, or before and after long-term shutdowns. After purging, samples must be analyzed, and work may only proceed once the oxygen content in the nitrogen does not exceed 0.5%. Hydrogen concentration alarms within the station must remain operational during removal until the system is fully inerted.

Hydrogen compressor removal in the energy storage and electronic semiconductor sectors places greater emphasis on material traceability. Hydrogen embrittlement is a key potential risk for metal components in high-pressure hydrogen environments; even austenitic stainless steel or nickel-based alloys may experience performance degradation due to prolonged exposure to hydrogen. A study on stainless steel diaphragms showed that, after prolonged exposure to gaseous hydrogen in service, the total hydrogen concentration in the diaphragms increased by 103% to 243% compared to the material in its as-supplied state. Before dismantling, components must be assessed for cracks caused by prolonged hydrogen exposure to prevent degraded components from being mistakenly recycled or reused. Compressor dismantling in the electronics and semiconductor industries must follow cleanroom removal procedures to prevent particulate contamination of the facility environment.

Overview of Industry Differences in Maintenance and Dismantling

Decision-Making Logic for Coordinated Operations of Major Equipment

In the chlor-alkali industry, maintenance of hydrogen compressors, chlorine compressors, HCl furnaces, and graphite heat exchangers must be coordinated as a unified system. In maintenance scenarios, the core of this coordination lies in system shutdown and purging. Before performing maintenance on any piece of equipment, it must be completely disconnected from the process system and physically isolated by installing blind flanges to prevent chlorine gas from entering the work area. The entire system must be thoroughly purged and purged with nitrogen until it passes inspection. Maintenance of chlorine compressors focuses on system isolation, nitrogen purging, and energy lockout to prevent residual chlorine gas and accidental startup. Due to the high brittleness of graphite, specialized lifting equipment or soft slings must be used when handling and dismantling graphite heat exchangers; dropping, impacting, or crushing them is strictly prohibited. The HCl furnace must also be thoroughly purged before maintenance, and the condition of the graphite components and explosion-proof membranes inside the furnace must be inspected.

In dismantling scenarios, the core of coordination between hydrogen compressor removal and the decommissioning of the aforementioned equipment lies in comprehensive decommissioning and contamination control. A comprehensive dismantling plan covering these three pieces of equipment must be developed, clearly defining the dismantling sequence, lifting methods, and waste disposal procedures. Prior to dismantling, all connected pipelines must be thoroughly cleaned and purged; safety must be confirmed through sampling and analysis before any hot work or cutting is performed. The dismantling of the graphite heat exchanger must follow operating procedures for brittle materials, while also assessing whether the equipment has corroded or deteriorated due to prolonged exposure to chlorine and hydrogen chloride, to ensure components are disposed of in compliance with regulations.

Regardless of the industry, the core safety prerequisite for hydrogen compressor maintenance remains consistent: work may only begin after the system has been isolated, purged with nitrogen, and tested to ensure compliance. Differences lie in specific standards and operational details, not in the fundamental principles.