Application Status and Demand Analysis of Steel Pipes for New Energy

Literature Overview

This paper by Zhang Zhonghua and colleagues from Baoshan Iron and Steel Co., Ltd. and the National Key Laboratory of Oil and Gas Drilling and Production Equipment provides a comprehensive review of steel pipe applications in the new energy sector under China's "dual carbon" strategy. The study focuses on three critical areas: CO2 transport pipes in carbon capture, utilization and storage (CCUS), hydrogen transport pipes in the hydrogen energy domain, and injection-extraction pipes for salt cavern compressed air energy storage (CAES). Published in the journal "Steel Pipes" in 2024, this work represents a significant contribution to understanding how traditional steel pipe technology must evolve to meet emerging energy infrastructure demands.

Core Technical Points

The paper identifies three distinct application scenarios that impose fundamentally different requirements on steel pipe materials and manufacturing processes. Each scenario presents unique corrosion, mechanical, and integrity challenges that demand specialized solutions.

CO2 Transport Pipe Requirements

CO2 transport pipes face severe corrosion challenges due to the presence of water, which forms carbonic acid and significantly accelerates carbon steel degradation. The authors emphasize that dry CO2 (with moisture content below 100 ppm) poses manageable corrosion rates for standard carbon steel grades such as X65 and X70, while wet CO2 environments can cause corrosion rates exceeding 1 mm/year in unprotected carbon steel. The paper highlights the need for corrosion-resistant alloy pipes (CRA) or advanced internal coatings and cathodic protection systems for wet CO2 service. Key material considerations include resistance to CO2 corrosion (sweet corrosion), susceptibility to stress corrosion cracking (SCC), and long-term mechanical property retention under cyclic loading conditions typical of CCUS operations.

Hydrogen Transport Pipe Challenges

Hydrogen transport presents a unique set of challenges centered on hydrogen embrittlement (HE) and hydrogen-induced cracking (HIC). The paper discusses how hydrogen atoms, being the smallest elements, can diffuse into the steel matrix and accumulate at microstructural defects, grain boundaries, and inclusions, leading to loss of ductility and catastrophic failure at stresses well below yield strength. For hydrogen transport applications, the authors recommend pipelines with yield strength not exceeding 460 MPa (approximately X65 grade or lower) to minimize hydrogen embrittlement susceptibility. The microstructural requirements emphasize fine-grained, clean steel with controlled inclusion morphology and minimized segregation.

Salt Cavern CAES Injection-Extraction Pipe

For salt cavern compressed air energy storage systems, the injection and extraction pipes must withstand cyclic pressure loading, potential H2S corrosion from the salt formation environment, and long-term fatigue life requirements. The paper notes that these pipes typically operate under pressure cycles of 0.5 to 6.0 MPa with potential exposure to brine and dissolved gases, requiring materials with excellent fatigue crack growth resistance and corrosion resistance.

Standards and Material Selection Analysis

The paper discusses the evolving standards landscape for new energy steel pipes. Current standards such as API 5L, ISO 15590, and GB/T 9711 provide baseline requirements for line pipe, but the specific demands of new energy applications often exceed these conventional specifications. The authors advocate for the development of specialized standards addressing CO2 transport (e.g., NACE MR0175/ISO 15156 for sour service), hydrogen pipeline integrity, and CAES system requirements.

Engineering Practice Integration

From a manufacturing perspective, producing steel pipes for these new energy applications requires enhanced quality control measures. For hydrogen service pipes, additional testing such as slow strain rate testing (SSRT), hydrogen charging tests, and in-situ tensile testing under hydrogen environments should be incorporated into the quality assurance program. For CO2 transport pipes, accelerated corrosion testing and long-term coupon exposure tests are essential for material qualification.

The paper also raises important considerations regarding welding and fabrication. Welded joints in hydrogen service pipelines are particularly vulnerable to hydrogen-induced cracking due to the presence of coarse-grained heat-affected zones (HAZ) and potential microstructural heterogeneities. The authors recommend strict control of welding consumables, welding procedures, and post-weld heat treatment (PWHT) to minimize HAZ hardness and residual stress.

Study Insights and Implications

This literature provides a timely and comprehensive overview of how the steel pipe industry must adapt to the energy transition. The key insight is that new energy applications do not simply reuse existing pipe grades with minor modifications but often require fundamentally different material systems, manufacturing approaches, and quality assurance frameworks. The emphasis on basic research, key technology development, and standards system construction reflects the maturity of the field's understanding of these challenges. For practicing engineers, this paper serves as a valuable roadmap for identifying the technical gaps that must be addressed in the coming decade as new energy infrastructure scales up globally.