制氫轉(zhuǎn)化爐集合管加強(qiáng)接頭裂紋原因分析及處理

韓玉昌

摘 要：中國(guó)石化塔河煉化有限責(zé)任公司2#制氫轉(zhuǎn)化爐對(duì)流室轉(zhuǎn)化原料預(yù)熱段出口集合管的加強(qiáng)接頭出現(xiàn)了裂紋，導(dǎo)致裝置緊急停車。對(duì)開裂的爐管進(jìn)行了有限元分析，分析結(jié)果表明：工作時(shí)由于爐管與旁邊的橫梁接觸，使加強(qiáng)接頭在外壁產(chǎn)生了最大應(yīng)力，最大應(yīng)力值為90.3 MPa，此應(yīng)力高于632 ℃下材料的許用應(yīng)力，因此導(dǎo)致爐管開裂。同時(shí)，還對(duì)爐管開裂位置的母材進(jìn)行了金相分析，發(fā)現(xiàn)開裂位置的母材晶粒粗大，并有碳析出，導(dǎo)致晶界弱化。根據(jù)應(yīng)力分析和金相分析結(jié)果，對(duì)爐管熱膨脹定位方式進(jìn)行了整改，有效地消除了爐管應(yīng)力。整改后對(duì)裂紋部位進(jìn)行了打磨、焊接，并在檢驗(yàn)合格后再次投用生產(chǎn)。

關(guān) 鍵 詞：轉(zhuǎn)化爐；爐管；有限元；金相組織

中圖分類號(hào)：TQ 116 文獻(xiàn)標(biāo)識(shí)碼： A 文章編號(hào)：1006-1878（2015）07-1684-03

Reason Analysis and Treatment Measures of the Crack on the Strengthened

Joint of the Collection Tube of the Hydrogen Reformer Furnace

HAN Yu-chang

（Sinopec Tahe Petrochemical Co.， Ltd.，Xinjiang Kuche 842000， China）

Abstract： Cracks were found on the strengthened joint of the export collection tube in the preheating section for transformation materials of the 2# hydrogen reformer furnace convection cell in Tahe branch. In this paper， the cracked furnace tube was analyzed through finite element method. It was shown that the maximum stress of the strengthened joint was located at the outer wall because of the contact between the furnace tube and the beam beside during the work. The maximum stress was as high as 90.3 MPa， which is higher than the allowable stress of the material at 632 ℃， resulting in the cracking of the furnace tube. At the same time， the metallographic structure of the parent metal at the crack of the furnace tube was also analyzed. Its found that the grain of the parent metal was coarse， with carbon precipitating out， thus causing the grain boundary weaken. According to the results of the stress analysis and metallographic analysis， the position method for the thermal expansion of the furnace tube was rectified， and the stress of the furnace tube was eliminated effectively. After the rectification， the crack position was then ground and welded. The device was put into service again after passing inspection.

Key words： Reformer； Furnace tube； Finite element； Metallographic structure

中國(guó)石化塔河煉化有限責(zé)任公司2萬標(biāo)m3/h時(shí)制氫裝置于2010 年9 月投入運(yùn)行，本裝置是由洛陽院總承包，轉(zhuǎn)化爐對(duì)流段盤管是由哈爾濱哈鍋工程技術(shù)有限責(zé)任公司制造，中石化第十建設(shè)公司安裝施工。

2011年6月20日， 2#制氫轉(zhuǎn)化爐（0213-F101）對(duì)流室轉(zhuǎn)化原料預(yù)熱段出口集合管的加強(qiáng)接頭發(fā)生泄漏，導(dǎo)致裝置緊急停車。經(jīng)檢查，發(fā)現(xiàn)共有兩個(gè)加強(qiáng)接頭出現(xiàn)裂紋，裂紋部位均位于加強(qiáng)接頭的拐角處。一個(gè)4#管，另一個(gè)2#管，經(jīng)過緊急搶修，于2011年7月2日恢復(fù)生產(chǎn)。2011年10月27日，2#管的加強(qiáng)接頭再次發(fā)生泄漏，裂紋位置處于上次修補(bǔ)焊縫的下融合線處的熱影響區(qū)內(nèi)。本文采用有限元分析方法和金相組織分析，主要探討加強(qiáng)接頭出現(xiàn)裂紋的原因，并對(duì)裂紋采取有效地修復(fù)措施。

本文結(jié)合兩次泄露事故分析及處理，對(duì)制氫轉(zhuǎn)化爐集合管加強(qiáng)接頭裂紋原因進(jìn)行了分析，并根據(jù)分析結(jié)果采取有效的處理。對(duì)制氫轉(zhuǎn)化爐的安全運(yùn)行管理及事故分析具有一定的指導(dǎo)意義。

1 轉(zhuǎn)化爐技術(shù)參數(shù)

轉(zhuǎn)化原料氣中主要含有H2O、H2、CO2、CO、CH4、N2等。原料預(yù)熱段的操作壓力為2.65 MPa、設(shè)計(jì)壓力為3.25 MPa，操作溫度為560～610 ℃、設(shè)計(jì)溫度為630 ℃。轉(zhuǎn)化爐加強(qiáng)接頭的材質(zhì)為F347H、集合管和爐管的材質(zhì)為TP347H。加強(qiáng)接頭鍛件經(jīng)過固熔處理，接頭與集合管焊接后進(jìn)行了整體穩(wěn)定化熱處理。