硫回收装置余热锅炉铵盐结晶腐蚀机理研究  

Study on the corrosion mechanism of ammonium salt crystallization in waste heat boiler of a sulphur recovery unit

作　　者：苏国庆 李彦 窦站 张建文[1] 张志军 SU Guoqing;LI Yan;DOU Zhan;ZHANG Jianwen;ZHANG Zhijun(School of mechanical and electrical engineering,Beijing University of Chemical Technology,Beijing 100029,China;National Energy Group Ningxia Coal Industry Co.,Ltd.,Coal to Oil Branch,Yinchuan 750411,China)

机构地区：[1]北京化工大学机电工程学院,北京100029 [2]国家能源集团宁夏煤业有限责任公司煤制油分公司,银川750411

出　　处：《压力容器》2024年第6期73-82,共10页Pressure Vessel Technology

基　　金：国家重点研发计划项目(2021YFB3301100);北京化工大学交叉学科项目(XK2023-07)。

摘　　要：针对某公司硫回收装置余热锅炉在运行过程中出现了大范围的结晶现象、给装置带来了流道沉积堵塞和设备腐蚀泄漏等严重问题,重点研究结晶对设备的腐蚀机理。利用扫描电镜(SEM)、能谱仪(EDS)和X射线衍射仪(XRD)分别测定了结晶样品的微观结构、元素分布和物相组成。结果表明,结晶样品的微观结构呈现平滑致密和粗糙多孔两种形态,晶粒尺寸在20~50μm;所含元素种类主要有N,O,S,Fe,C,其中余热锅炉列管内结晶底面Fe含量达到了35%,说明沉积结晶对设备有较强的腐蚀作用;主要物相组成为NH_(4)HSO_(4),(NH4)_(2)SO_(4),(NH_(4))_(3)H(SO_(4))_(2)等铵盐;制硫尾气中含有的NH3是结晶形成的根本原因。此外,对不同区域的腐蚀过程进行了详细阐述,为该装置同类问题的研究和解决提供参考。The waste heat boiler of a company's sulphur recovery unit encountered a wide range of crystallization phenomenon during operation,causing serious problems to the unit such as flow channel deposition blockage and equipment corrosion and leakage.This study focused on the corrosion mechanism of crystallization on equipment.The microstructure,elemental distribution and phase composition of the crystalline samples were determined using scanning electron microscope(SEM),energy spectrometry(EDS)and X-ray diffractometer(XRD),respectively.The results show that the microstructures of the crystalline samples exhibit both smooth and dense and rough and porous morphologies,with grain sizes in the range of 20~50μm.The elements contained are mainly N,O,S,Fe and C,in which the Fe content on the bottom surface of the crystalline samples in the column tubes of the waste heat boiler reaches 35%,indicating that the deposited crystals have a strong corrosive effect on the equipment.The main phases of the crystallites are ammonium salts such as NH_(4)HSO_(4),(NH_(4))_(2)SO_(4)and(NH_(4))_(3)H(SO_(4))_(2).The NH_(3)contained in the tail gas of sulphur production is the root cause for the formation of the crystallites.In addition,the corrosion processes in different regions were described in detail.It provides reference for the research and solution of similar problems in the device.

关 键 词：余热锅炉 硫回收装置 铵盐 结晶 腐蚀机理 

分 类 号：TH49[机械工程—机械制造及自动化] TK229.92[动力工程及工程热物理—动力机械及工程] TG174.3[金属学及工艺—金属表面处理]