石油化工腐蚀与防护
石油化工腐蝕與防護
석유화공부식여방호
PETROCHEMICAL CORROSION AND PROTECTION
2012年
3期
60-64
,共5页
制氢%苯菲尔溶液%腐蚀%缝隙
製氫%苯菲爾溶液%腐蝕%縫隙
제경%분비이용액%부식%봉극
hydrogen generation%Benfield solution%corrosion%crevice corrosion
简要描述了制氢装置再生塔底重沸器运行工况,通过现场检查换热管腐蚀形貌,以及对工艺介质的组成、管束的材质分析、泄漏点的腐蚀产物分析、试样的金相分析,明确了再生塔底重沸器由于装置长周期运行,水分的蒸发造成苯菲尔溶液中微量的Cl-浓度不断浓缩,形成Cl-在管板和换热管中间的缝隙富集,导致缝隙与壳体内溶液形成浓度差,从而形成缝隙腐蚀,缝隙腐蚀形成的点蚀造成再生塔底重沸器的泄漏。针对上述腐蚀分析原因,从技术及管理角度制定相应的整改措施。为消除缝隙的存在,通过技术实验,对比了管束加工制作方式的差异,指明管束制作应根据生产实际需要选择合适的加工工艺。
簡要描述瞭製氫裝置再生塔底重沸器運行工況,通過現場檢查換熱管腐蝕形貌,以及對工藝介質的組成、管束的材質分析、洩漏點的腐蝕產物分析、試樣的金相分析,明確瞭再生塔底重沸器由于裝置長週期運行,水分的蒸髮造成苯菲爾溶液中微量的Cl-濃度不斷濃縮,形成Cl-在管闆和換熱管中間的縫隙富集,導緻縫隙與殼體內溶液形成濃度差,從而形成縫隙腐蝕,縫隙腐蝕形成的點蝕造成再生塔底重沸器的洩漏。針對上述腐蝕分析原因,從技術及管理角度製定相應的整改措施。為消除縫隙的存在,通過技術實驗,對比瞭管束加工製作方式的差異,指明管束製作應根據生產實際需要選擇閤適的加工工藝。
간요묘술료제경장치재생탑저중비기운행공황,통과현장검사환열관부식형모,이급대공예개질적조성、관속적재질분석、설루점적부식산물분석、시양적금상분석,명학료재생탑저중비기유우장치장주기운행,수분적증발조성분비이용액중미량적Cl-농도불단농축,형성Cl-재관판화환열관중간적봉극부집,도치봉극여각체내용액형성농도차,종이형성봉극부식,봉극부식형성적점식조성재생탑저중비기적설루。침대상술부식분석원인,종기술급관리각도제정상응적정개조시。위소제봉극적존재,통과기술실험,대비료관속가공제작방식적차이,지명관속제작응근거생산실제수요선택합괄적가공공예。
The operating conditions of the bottom reboiler in a hydrogen plant are briefed.Through field examination of topographic form of heat exchanger tubes,analysis of process media compositions,tube metallurgy and corrosion product at the leaking points and well as metallographic analysis of samples,it is concluded that the leaking of regeneration tower bottom reboiler is the result of pitting corrosion from crevice corrosion because of the concentration difference between the solution in crevice and the solution in shell resulted from continuous increased concentration of Cl-in Benfield solution with water vaporization and accumulation of Cl-in the crevice between tube sheet and tube.The preventive measures are purposed in respect of technology and management.It is pointed out that appropriate manufacturing process should be selected for the tubes based upon the actual operation requirements.
