Tao Wenting, Chen Ruyi

(Guangdong Furan Tiangao Fluid Machinery Equipment Co., LTD., Foshan, Guangdong 528000)

[Abstract] : Hazard and Operability (HAZOP) analysis, as a widely adopted risk assessment tool in the chemical industry, has significant advantages in identifying potential hazards in process systems through its systematic and structured analysis methods. Taking the hydrogen compressor of the hydrogen refueling station as the research object, based on the HAZOP analysis method and combined with specific design cases, a comprehensive risk identification and assessment of the compressor system is conducted. By constructing a deviation analysis matrix, factors such as high-pressure hydrogen leakage and mechanical seal failure were identified

Key risk factors are identified, and then a multi-parameter collaborative monitoring mechanism and a hierarchical interlock protection strategy are proposed. The research results show that this method can effectively reduce the occurrence probability of key risks, providing a technical reference for the intrinsically safe design of core equipment in hydrogen refueling stations, and is of great significance for promoting the safe development of the hydrogen energy industry. Meanwhile, the improvement plans for the applicability of the HAZOP analysis method under special working conditions were also discussed, providing new ideas for the safety assessment of similar high-pressure gas processing equipment.

[Key words] : HAZOP Analysis Safety of hydrogen refueling stations; Hydrogen compressor; Risk matrix Intrinsic safety

Chinese Library Classification Number: TH456 Document Code: A

Article Number: 1006-2971 (2026) 01-0023-04

1 Introduction

With the in-depth advancement of the ";dual carbon" strategy, China's hydrogen energy industry has entered a stage of rapid development. According to statistics from the China Hydrogen Energy Alliance, by the end of 2023, 428 hydrogen refueling stations had been built across the country, and it is expected that the number will exceed 1,000 by 2025 [1]. However, while the industry is expanding rapidly, safety accidents at hydrogen refueling stations occur frequently, especially major accidents involving hydrogen compressors, accounting for as high as 63% (based on accident statistics from 2020 to 2023). As a widely used risk assessment tool in the field of industrial safety, Hazard and Operability Study (HAZOP) has formed a mature standardized application framework, with standardized operation procedures and a large number of successful application cases. The current technical standard system in our country has put forward specific requirements for the implementation of HAZOP analysis. Standard documents such as ";Application Guidelines for Hazard and Operability Analysis (HAZOP Analysis)"; (AQ/T3049-2013) [2] and "Implementation Guidelines for Hazard and Operability Analysis"; (Q/SH0559-2013) [3] have all clearly expounded on the application value of HAZOP analysis. These technical specifications not only establish the status of the HAZOP method at the institutional level, but also make detailed provisions on its specific implementation requirements and scope of application. Through standardized deviation identification and risk assessment processes, HAZOP technology can effectively enhance system safety and reduce the accident rate.

2 HAZOP analysis method system

2.1 HAZOP analysis Method, Figure 1

HAZOP analysis, as a systematic safety assessment method, is usually carried out by cross-disciplinary teams in the form of structured meetings. Under the organization of the professional team leader, team members conducted an in-depth review of the process flow using a standardized guiding word system, systematically identifying various potential risks that might deviate from the design expectations. This analysis method requires the provision of complete process technology data, including detailed pipeline and instrument flowcharts and design documents. Through a comprehensive assessment of key operating parameters (such as fluid characteristics, pressure control, temperature regulation, etc.), it analyzes abnormal situations that may be caused by deviations in various operating conditions. During the research process, specific guiding words (such as abnormal flow, pressure fluctuation, etc.) were used to qualitatively describe each potential deviation, deeply analyze its causes and possible consequences, and based on this, a special analysis matrix was constructed, ultimately forming a risk prevention and control countermeasure based on design optimization.

2.2 Risk Level Classification Standards

The HAZOP analysis carried out in this study strictly adhered to the national industry standard for work safety, ";Application Guidelines for Hazard and Operability Analysis (HAZOP Analysis)" (AQ/T3049-2013) [2], and the group standard of the China Chemical Safety Association, "Guidelines for Quality Control and Review of Hazard and Operability Analysis". The technical specification requirements of (T/CCSAS001-2018) [4]. During the analysis process, the formulation of risk assessment criteria is mainly based on three core dimensions: (1) Grading assessment of the severity of risk impact; (2) Classification of the likelihood of risk occurrence; (3) Construction and Application of risk matrix. Meanwhile, the research, in combination with the acceptable risk standards of the project owner unit, made adaptive adjustments to the risk level classification method in the above standards to ensure that the analysis results not only comply with industry norms but also meet the specific safety management needs of the project. This technical route that combines standardized analytical methods with customized evaluation criteria effectively guarantees the scientific nature and applicability of HAZOP analysis results.

Risk consequence Level A: Low consequences occur, may cause temporary discomfort to personnel, the impact is limited to the interior of the device, the resulting losses are negligible, and it will not have a negative impact on the company's reputation.

Risk consequence Level B: It may result in relatively low consequences, potentially causing minor physical injuries to personnel for a short period of time, and incurs relatively small losses in all aspects of the company. The incident does not trigger administrative penalties and has a relatively low impact on the company's image and reputation within a small range.

Risk consequence Level C: Moderate consequences may occur, potentially causing occupational diseases among personnel, significant losses to the company in all aspects, and the incident may be notified by the management department or violate the permitted conditions, with a minor impact on the company's image and reputation.

Risk consequence Level D: High consequences may occur, potentially causing 1 to 2 deaths, 3 to 6 serious injuries, significant losses in all aspects of the company, major leakage will have a serious impact outside the workplace, and cause considerable negative effects on the company's image and reputation.

Risk consequence Level E: It may result in very high consequences, potentially causing the death of more than 3 people, serious injury to more than 10 people, significant losses in all aspects of the company, extensive regional impact, and a major negative impact on the company's image and reputation.

HAZOP Analysis of the Hydrogen Compressor System in Hydrogen Refueling stations

3.1 Function and Role of the Hydrogen Refueling Station Compressor

The core system of a hydrogen refueling station consists of four functional units: hydrogen receiving unit, pressure boosting unit, hydrogen storage unit and filling service unit. Among them, the core equipment of the hydrogen receiving unit includes dedicated transport vehicles (long tube trailers) and the corresponding unloading devices, which achieve the safe transfer of hydrogen through dedicated interfaces.

The key process equipment within the station consists of three major parts: hydrogen compression devices for pressurization, high-pressure container groups for storage, and refueling equipment for terminal services. The commonly used compressors in hydrogen refueling stations include diaphragm compressors and liquid-driven compressors. Hydrogen compressors serve as the main equipment for pressurizing hydrogen refueling stations.

3.2 Implementation of HAZOP Analysis for Hydrogen Refueling Station Compressors

This study selects the hydrogen diaphragm compressor unit of the hydrogen refueling station as the key research object. By using the structured analysis method, it conducts systematic risk identification and assessment of core subsystems such as the main unit body, process gas pipeline, lubrication system pipeline, and cooling water circulation pipeline from the perspective of equipment composition, aiming to comprehensively identify potential safety hazards in the compressor system.

3.3 HAZOP Node Division and Deviation Explanation of Hydrogen Refueling Stations, Table 1

This paper takes the gas path of a hydrogen compressor as a node, selects deviations in flow rate, pressure, liquid level, temperature, and leakage components, such as too little, too much, too high, too low, and too large deviations. Based on these guiding words, it analyzes the causes and consequences of the deviations, as well as the existing measures and suggested measures.

4. Risk Analysis and Recommendations

4.1 HAZOP analysis Results of the compressor

Select HAZOP nodes and deviation contents, and conduct HAZOP analysis and record. Based on the causes of the deviation analysis and the possible accidents it may lead to, corresponding safety measures were identified. Thus, the HAZOP analysis record table for the hydrogen compressor unit is formed as shown in Table 2 (excerpt). Through the HAZOP analysis, low-risk, medium-risk, and high-risk items were found in the hydrogen compressor system, but no very high-risk items were discovered. Serious consequences were identified as low consequences, medium consequences, and high consequences, with no very high consequence level. The following risks are identified through HAZOP analysis (excerpt) :

Impurities in the hydrogen gas cause the gas measurement diaphragm of the diaphragm compressor to rupture, allowing lubricating oil to enter the hydrogen system, resulting in impure products and contamination of the hydrogen system.

(2) The sealing failure of pipelines and connection points led to hydrogen leakage. When exposed to fire, the hydrogen exploded, causing injuries to people, property damage and environmental pollution.

(3) The quality of the lubricating oil was substandard, causing the diaphragm to rupture and resulting in the compressor being unable to operate normally.

(4) Hydrogen leaked into the circulating water system, causing injury to personnel, property damage and environmental pollution.

(5) Hydrogen gas intruded into the nitrogen gas pipeline network, causing hydrogen leakage and contaminating the nitrogen gas pipeline, resulting in personal injury, property damage and environmental pollution.

(6) The upstream hydrogen supply was insufficient. The compressor idled and was evacuated, causing the diaphragm to rupture and hydrogen to leak.

4.2 Risk Response Suggestions and Measures

(1) Dual filters are installed at the inlet of the hydrogen compressor, and nitrogen displacement purging is carried out simultaneously when the machine is started.

(2) Establish an equipment inspection system, regularly test and record the compressor pipelines, and set up a hydrogen concentration alarm device;

(3) In the procurement process, strictly control the quality of procurement to ensure the purchase of genuine lubricating oil.

(4) Strictly enforce the flaw detection system for hydrogen pipelines and at the same time, strictly control the quality of materials.

(5) A check valve is installed at the nitrogen purging port to prevent hydrogen backflow.

(6) A low hydrogen flow alarm is set for the intake buffer tank at the compressor inlet.

5 Conclusion

This study conducted a systematic risk assessment of the process parameters and operation procedures of the hydrogen compressor system based on the Hazard and Operability (HAZOP) analysis method. By establishing a complete deviation analysis matrix, several key risk factors were identified. Given the particularity of the operating environment of hydrogen compressors in hydrogen refueling stations, the research focuses on the risk of hydrogen leakage and the pollution hazards caused by diaphragm rupture. HAZOP analysis provides important insights for the safety management of hydrogen systems in hydrogen refueling stations:

(1) In terms of design optimization: Through systematic analysis, potential defects in the compressor design can be effectively identified, key control points for equipment maintenance and upkeep can be clarified, and other risk factors that may have been overlooked can be discovered.

(2) In terms of risk control: Based on the analysis results, targeted risk control measures are formulated. Through process optimization and system improvement, the risk level and the severity of accident consequences are significantly reduced, achieving an overall improvement in safety standards.

(3) In terms of training and guidance: Provide scientific basis for equipment suppliers to enable them to compile more targeted training materials and operation manuals, helping users accurately grasp the key points of the process and risk identification methods.

(4) In terms of safety and emergency management: Strengthen the training of emergency response capabilities for hydrogen refueling station operators, standardize operation procedures, ensure the stable operation of compressors, and thereby enhance the overall safety and reliability of hydrogen refueling stations.

References

[1] China Hydrogen Energy Alliance China Hydrogen Energy Industry Development Report 2023 [R] Beijing: China Hydrogen Energy Alliance, 2023.

[2] State Administration of Work Safety. AQ/T3049-2013, Application Guidelines for Hazard and Operability Analysis (HAZOP Analysis) [S]. Beijing: Coal Industry Press, 2013.

[3] China Petrochemical Corporation. Q/SH0559-2013, Guidelines for the Implementation of Hazard and Operability Analysis [S] Beijing: Sinopec Press, 2013.

[4] China Chemical Safety Association T/CCSAS001-2018, Guidelines for Quality Control and Review of Hazard and Operability Analysis [S]. "2018.

Author's Profile: Tao Wenting (1993-), male, from Wuxue, Hubei Province, assistant engineer, bachelor's degree, engaged in the research and design of compressors