化工设计

本文针对煤气化装置合成气管线在高温、高压及复杂腐蚀性环境下易发生腐蚀失效的问题，开展了系统化的材料选择研究。以水煤浆气化(项目A)与粉煤气化(项目B)为工程案例，选取气化炉激冷室出口至洗涤塔入口(A1与B1)与洗涤塔出口至变换炉入口(A2与B2)四组关键工况数据，通过水露点计算与腐蚀组分分压分析，系统分析了其腐蚀环境特征。研究表明：管线主要失效机理包括二氧化碳(CO₂)/硫化氢(H_2S)酸性腐蚀、湿H_2S氢损伤、氯化物应力腐蚀开裂及冲刷腐蚀等，并将A1与B1段划分为高风险、A2与B2段划分为中风险。据此提出分段差异化选材策略：高风险段推荐采用奥氏体不锈钢或高耐蚀合金；中风险段则在工艺防护(如可靠伴热)得以保障的前提下，优先选用抗氢致开裂低合金钢以优化经济性，亦可直接选用不锈钢以获得更高的可靠性。本研究构建了从环境评估、机理识别、风险分级到技术经济比选的系统化选材决策框架，为工程实践提供了兼顾安全性与经济性的科学依据。

This paper conducts a systematic study on material selection to address the issue of corrosion failure of syngas pipelines in coal gasification units under high temperature,high pressure and complex corrosive environments.Taking coal water slurry gasification(Project A) and pulverized coal gasification(Project B) as engineering cases,four sets of key operating condition data are selected from the gasifier quench chamber outlet to the scrubber inlet(A1 and B1) and the scrubber outlet to the shift converter inlet(A2 and B2).Through water dew point calculation and corrosion component partial pressure analysis,the corrosion environment characteristics are systematically analyzed.Research has shown that the main failure mechanisms of pipelines include CO2/H2S acid corrosion,wet H2S hydrogen damage,chloride stress corrosion cracking and erosion corrosion.Based on the risk matrix,sections A1 and B1 are classified as high-risk,while sections A2 and B2 are classified as medium risk.Based on this,a segmented differentiated material selection strategy is proposed:austenitic stainless steel or high corrosion resistant alloys are recommended for high-risk sections.In the medium risk stage,under the premise of ensuring process protection(such as reliable heat tracing),low-alloy steel with hydrogen induced cracking resistance is preferred to optimize economy,and stainless steel can also be directly used to achieve higher reliability.This study constructs a systematic material selection decision-making framework from environmental assessment,mechanism identification,risk classification to technical and economic comparison,providing a scientific basis for engineering practice that balances safety and economy.