煤制甲醇氣化與變換單元的能效優(yōu)化

第31卷第5期針算機與應用化學(xué)Vol 31. No 52014年5月28日Computers and Applied Chemistryay28,2014煤制甲醇氣化與變換單元的能效優(yōu)化齊少寧1,李士雨李金來(lái)2(1.天津大學(xué)化工學(xué)院,天津,300072;2.新奧科技發(fā)展有限公司,河北,廊坊,065001)摘要:以某60萬(wàn)噸/年煤制甲醇裝置為背景,選取氣化與變換單元為研究對象,利用夾點(diǎn)技術(shù)對其用能現狀進(jìn)行了分析,找出違背夾點(diǎn)規則的不合理?yè)Q熱匹配并提出2套優(yōu)化方案,結果如下:方案1:減少副產(chǎn)0.3Mpag蒸汽53.8%(工廠(chǎng)該品質(zhì)蒸汽過(guò)剩),增產(chǎn)1.2Mpag蒸汽65%新增產(chǎn)25Mpag蒸汽18.83MW;方案2:減少0.3Mpag蒸汽510%,增產(chǎn)12Mpag蒸汽222%當1.2與2.5Mpag蒸汽價(jià)格相差不大、設備材料費用較高時(shí),方案2優(yōu)于方案1。關(guān)鍵詞:夾點(diǎn)技術(shù);換熱網(wǎng)絡(luò );煤炭氣化;變換;煤制甲醇中圖分類(lèi)號:TQ5464文獻標識碼:A文章編號:1001-41602014)05-601-604DOI: 10. 11719/com. app. chem20140519工智能法以?shī)A點(diǎn)技術(shù)法4。其中,夾點(diǎn)技術(shù)法由于引言其簡(jiǎn)單、直觀(guān)、計算量小而得到了廣泛的應用。夾點(diǎn)技氣化和變換是煤制甲醇工藝的上游單元,系統高溫術(shù)在煉油石油化工及其他化工裝置0等都取得物流的溫度高達415℃,而最終要降到40℃左右,因了顯著(zhù)的節能效果,但是在煤炭氣化和變換工業(yè)的應用此可以通過(guò)副產(chǎn)蒸汽回收系統能量用于后續單元。根據報道不多熱力學(xué)第二定律可知,能量具有不同的品質(zhì)。高壓蒸汽本文以某廠(chǎng)60萬(wàn)噸/年煤制甲醇裝置為背景,選取具有的能量品質(zhì)高于低壓蒸汽具有的能量品質(zhì)。故而,處于上游的煤炭氣化與變換單元作為1個(gè)系統,利用夾可以通過(guò)提高高壓蒸汽的產(chǎn)量、降低低壓蒸汽產(chǎn)量對氣點(diǎn)技術(shù)法對該系統的用能現狀進(jìn)行了分析,在此基礎上化和變換工藝進(jìn)行能效優(yōu)化,提高能量回收效益提出了2套優(yōu)化方案,顯著(zhù)降低了低壓蒸汽的產(chǎn)量、提目前運用的能效優(yōu)化方法主要有數學(xué)規劃法習、人高了高壓蒸汽的產(chǎn)量。HI+H3E05R01Waste waterE10CondensateRo1--gasifier; R02-shift converter; TOl-syngas scrubber; TO2-ammonia scrubber, Vo1-HP flash drum; Vo2--LP flash drum; Vo3--NO Ivacuum flash drum; V04--NO 2 vacuum flash drum; VO5-NO I water separator; V06--NO I water separator; Hi- hot stream i; Cj-cold streamRo-氣化爐;R02—變換爐;τol—洗滌塔;T02—洗氨塔;vol—高壓閃蒸罐;V02—低壓閃蒸罐;V03一第一真空閃蒸罐;V04第二真空閃蒸罐ⅴ05一第一水分離器;v06—第二水分離器:Hi-第i股熱物流;Cj·第j股冷物流Fig 1 Process flowchart of coal gasification and shift units圖1煤炭氣化與變換工藝流程圖中國煤化工收稿日期:2013-08-18;修回日期:2013-11-14CNMHG作者簡(jiǎn)介:齊少寧(1987一),女,河北人,碩士研究生, E-mail: shaoning19871016@126com聯(lián)系人:李士雨(1964),男,天津人,博士,教授, E-mail: shylil26@126com602針算機蜀痃用化學(xué)2014,31(5)2氣化與變換單元物流分析Aspen Energy analyzer軟件分析得,系統夾點(diǎn)溫度(表2)、平衡總組合曲線(xiàn)(圖2)、以及各品質(zhì)公用工程能量21背景工藝簡(jiǎn)介目標(表3)。在此基礎上建立現有換熱網(wǎng)絡(luò )(圖3),從以60萬(wàn)噸年煤制甲醇裝置為背景,水煤漿氣化與而得到現有換熱網(wǎng)絡(luò )各公用工程消耗情況(表3)。變換單元的工藝流程簡(jiǎn)圖如圖1所示。表2夾點(diǎn)溫度該裝置氣化單元采用德士古水煤漿氣化工藝1314Table 2 Pinch水煤漿與氧氣混合進(jìn)入氣化爐R01進(jìn)行氧化反應,出氣夾點(diǎn)T/℃2/℃化爐的氣體去往洗滌塔T01;洗滌塔頂水煤氣去往變換pinch單元;氣化爐、洗滌塔底排出的黑水進(jìn)入閃蒸系統。公用工程夾點(diǎn)1258該裝置的變換單元采用的是鈷鉬催化劑低溫耐硫工utility pinch公用工程夾點(diǎn)2藝。水煤氣經(jīng)冷卻、閃蒸進(jìn)入E05預熱,而后去變換爐191.6utility pinch 2R02進(jìn)行變換反應,反應后的氣體H1被反應氣體C9冷公用工程夾點(diǎn)卻后,與配料氣體H3混合,使H2CO達到2.05±0.05 utility pinch335的設計要求,送往后續單元回收熱量。最后進(jìn)入洗氨TI-hot stream temperature: T2-cold stream temperature塔T02洗去氣體中的氨,塔頂得到變換氣去往凈化工序η1-熱物流溫度;2-冷物流溫度2.2工藝物流數據只需要冷公用工程或熱公用工程的問(wèn)題,稱(chēng)之為閾氣化與變換單元物流提取數據如表1所示,其中有值問(wèn)題。閾值問(wèn)題的節能降耗主要在于尋找跨越公用工熱物流8股、冷物流4股;公用工程為循環(huán)冷卻水及03、程夾點(diǎn)的不合理?yè)Q熱,并提出相應的優(yōu)化措施,降低公12、2.5Mpag發(fā)生蒸汽。需要特別注意的是,現有換熱用工程的品位(降低熱公用工程的溫度或提高冷公用工網(wǎng)絡(luò )和改造方案2級聯(lián)圖中的熱物流H1+H3(表1未列程的溫度)1。氣化與變換工藝為只需要冷公用工程的出)。反應后氣體H1與反應氣體C9換熱后,和配料氣閾值問(wèn)題,因此本文的節能降耗主要為提高冷公用工程體H3不等溫混合,所得物流為H+H3。但是,在改造的溫度,具體方案為提高高壓蒸汽的產(chǎn)量、降低低壓蒸方案1中為了能夠得到更多的換熱機會(huì )、副產(chǎn)更多高品汽的產(chǎn)量、減少冷卻水的消耗量質(zhì)的蒸汽,H1和H3并不混合而是分別冷卻到ⅴ06的入圖2為系統的平衡總組合曲線(xiàn),圖中也標出了現有口溫度換熱網(wǎng)絡(luò )公用工程?？梢园l(fā)現現有換熱網(wǎng)絡(luò )中公用工程表1工藝物流數據Table 1 Process streams匹配不合理,存在多處跨越夾點(diǎn)的換熱,浪費了高溫熱物流編號物流名稱(chēng)源的品質(zhì)。對比現有換熱網(wǎng)絡(luò )各公用工程消耗與能量目Ti/℃Tou℃△HMWstream NO標的具體值(如表3所示),可知現有換熱網(wǎng)絡(luò )具有很大415.2186.32391反應后氣體的節能潛力。157.0水煤氣0.3248215.C9338215.021440.0295配料氣體214430.85公用工程夾點(diǎn)公用工程夾點(diǎn)2高壓閃蒸汽1795174.924.67二分153.05.666離器有換熱網(wǎng)絡(luò )公用工程24.97100 FUtility consumption of current HEN500能量目標密封泵出水104.02.225arget公用工程夾點(diǎn)3第一真空汽6.11480100120140160180第二真空汽反應氣體215.03.609Fig 2 Balanced grand composite curve of gasification and shiftC10水111.0176.6中壓鍋爐水104.01458圖2氣化和變換工藝的平衡總組合曲線(xiàn)工藝脫鹽水32匹配不合理之處3甲醇裝置氣化與變換單元的用能分析夾點(diǎn)設計規則為:夾點(diǎn)之上不應放置公用工程冷卻器;夾點(diǎn)之中國煤化工;不應有跨越3.1節能潛力分析夾點(diǎn)的換熱器CNMHG存在多處跨越從系統實(shí)際操作工況、設備投資費用以及操作費用夾點(diǎn)的不合理?yè)Q熱為等因素綜合考慮,取最小換熱溫差△Tmin=15℃。利用①公用工程夾點(diǎn)1處:E05和E06分別為H1和H1+H32014,31(5)齊少寧,等:煤制甲醇氣化與變換單元的能效優(yōu)化冷卻器,H和H1+H3溫度均在該夾點(diǎn)以上,卻被夾點(diǎn)以下又可以消除E07跨越公用工程夾點(diǎn)換熱、提高冷公用工程的C9和CU3冷卻的溫度。②公用工程夾點(diǎn)2處:E07為H1+H3的冷卻器,溫度②新增冷卻器N02:H3的溫度在公用工程夾點(diǎn)1以下在該夾點(diǎn)以上,卻用了CU2冷卻。將E06移到H3上,消除了跨越公用工程夾點(diǎn)的不合理?yè)Q熱。③公用工程夾點(diǎn)3處:E10為H5冷卻器,溫度在該夾H3剩余的能量通過(guò)新加冷卻器N02副產(chǎn)0.3Mpag蒸汽回點(diǎn)以下,卻用C12來(lái)冷卻;E02、E11為H6和H7冷卻器,收。雖然工廠(chǎng)0.3Mpag蒸汽是過(guò)剩的,但是通過(guò)新增冷卻溫度在夾點(diǎn)以上,卻用冷卻水冷器NOl已經(jīng)降低很多,同時(shí)多余的蒸汽除用于工藝外,還2066可以供給辦公區應用、用于冬季供暖等,所以這部分的能量回收還是十分必要的。Hi+H3 069\1570081042i42改造方案2795E011749換熱網(wǎng)絡(luò )的改造過(guò)程中冷公用工程為循環(huán)冷卻水、0.3Mpag發(fā)生蒸汽、1.2Mpag發(fā)生蒸汽,不再副產(chǎn)新的25Mpag蒸汽。利用 Aspen Energy Analyzer軟件分析得,系統夾點(diǎn)為公用工程夾點(diǎn)2和工藝夾點(diǎn),能量目標如表C123所示,對現有換熱網(wǎng)絡(luò )分析發(fā)現換熱器E05不再跨越CUI夾點(diǎn),其他跨越夾點(diǎn)的換熱器不變。CU2改造后的換熱網(wǎng)絡(luò )如圖5所示,節能效果如表3所CU4261示。具體內容如下XP=.5 MW XP=20.9 MWXP4. Mw新增冷卻器N03:H1+H3初溫為3069℃,位于公用工程夾點(diǎn)2以上,新增冷卻器N03回收該物流夾點(diǎn)以Mpagsteam generation;CU3-12 Mpag steam generation;Cu4-25上的能量;該物流夾點(diǎn)以下的能量用來(lái)預熱1.2MpagXP跨越夾點(diǎn)傳遞的能量:CU-循環(huán)冷卻水:CU2.3Mpag發(fā)03Mpag發(fā)生蒸汽的鍋爐給水。生蒸汽:CU3-1.2Mpag發(fā)生蒸汽;CU4-25Mpag發(fā)生蒸汽與方案1相比,方案2只需新增1個(gè)換熱器,設備Fig 3 The grid diagram of current HEN投資低;1.2Mpag蒸汽產(chǎn)量大幅提高。圖3現有換熱網(wǎng)絡(luò )級聯(lián)圖HI4甲醇裝置氣化與變換單元的節能改造H2工廠(chǎng)副產(chǎn)的03Mpag蒸汽嚴重過(guò)剩,所以節能改造的主要目標是降低0.3Mpag的產(chǎn)量、提高12與25Mpag蒸汽的產(chǎn)量。H7H842.74.1改造方案1H205M261570CUICU2CU319XP4.5 MwFig. 5 The grid diagram of second optimized HEN圖5改造方案2的換熱網(wǎng)絡(luò )級聯(lián)圖CUICU2表3換熱網(wǎng)絡(luò )各級公用工程消耗CU3le 3 the utilities consumption of Hen用工程現有換熱目標1方案1目標2方案2Utilitytarget1w XP=0.0 MWXP= 5 MW/MWcurrent henFig 4 Grid diagram of first optimized HEN22.99185229918.52299圖4改造方案1的換熱網(wǎng)絡(luò )級聯(lián)圖2697224826.971119117.8119.2改造后的換熱網(wǎng)絡(luò )如圖4所示,節能效果如表3所CU4示。具體內容如下:中國煤化工①新增冷卻器N01:H被C9冷卻后溫度高達3809℃,5結論CNMHG新添加冷卻器N01副產(chǎn)25Mpag蒸汽18.83MW,剩余部分熱量由E07回收。這樣既可以副產(chǎn)25Mpag高壓蒸汽,氣化和變換單元是煤制甲醇工藝的上游單元,可以604針算機與應用化2014,31(5通過(guò)提高高壓蒸汽的產(chǎn)量、降低低壓蒸汽產(chǎn)量對氣化和13uJun. GE coal-water slurry gasification process overview. AnhuiChemical Industry, 2001, 01: 46-49變換工藝進(jìn)行能效優(yōu)化,提高能量回收效益14 Zhang Xudong and Bao Zonghong. Study on GE coal-water slurry氣化與變換工藝為只需要冷公用工程的閾值問(wèn)題。gasification equipment design. Journal of Chemical Industry andEngineering,2005,(04):3741,58本文利用夾點(diǎn)技術(shù)法找到了跨越工藝和公用工程夾點(diǎn)的15 Xiao Jiefei, Chen Guangqing and Zong Qiuyun..QDB03不合用能之處。并針對上述問(wèn)題提出了2套優(yōu)化方案。application at high pressure sulfur tolerant shift unit in GE方案1:使得工廠(chǎng)嚴重過(guò)剩的0.3Mpag低壓蒸汽量pressurized coal water gasification process. Chemical EngineeringDesign Communications, 2011, 37(2): 75-77降低了538%,工廠(chǎng)有用的2Mpg蒸汽量提高了16 In and Ding Danhong. Application of pinch technology in the65%,另外副產(chǎn)了新的25Mpag高壓蒸汽1883MW;17 Kemp Ian C Pinch analysis and process integration. 2nd ed. USA方案2:0.3Mpag蒸汽產(chǎn)量降低了51.0%,12Mpag蒸汽Elsevier Ltd. 2007.產(chǎn)量提高了222%。中文參考文獻當12與25Mpag蒸汽價(jià)格相差不大、設備材料費用較高時(shí),方案2優(yōu)于方案1。1張俊峰,羅雄麟.換熱網(wǎng)絡(luò )設計方法的研究進(jìn)展[門(mén).化工進(jìn)展,2005,6(24):625-628References:2李志紅,華賁,尹清華,等.人工智能與數學(xué)規劃的集成用于換熱網(wǎng)絡(luò )最優(yōu)合成設計的研究[門(mén)石油化工,1998,09:36441 Zhang Junfeng andUo Xinglin. Recent advances in optima!3趙輝,丁曉明,陳宏剛,等.換熱網(wǎng)絡(luò )綜合方法的研究進(jìn)展Usynthesis of heat exchanger networks. Chemical Industry andEngineering Process, 2005, 6(24): 625-628計算機與應用化學(xué),2009,26(101315-13182 Li Zhihong, Hua Ben and Yin Huaqing. The study design of heat5劉智勇,李志偉,霍磊.夾點(diǎn)理論及其在換熱網(wǎng)絡(luò )中的優(yōu)化分exchanger networks synthesis with integrated artificial intelligenceand mathematical programming method. Petrochemical析門(mén)節能技術(shù),2012,30(7:273-277Technology, 1998,6王成運.過(guò)程集成節能工藝夾點(diǎn)分析[D]中國石油大學(xué),20113 Zhao hui, Ding Xiaoming and Chen Honggang. Research7王瑞,付峰,高曉明,等.利用夾點(diǎn)技術(shù)優(yōu)化設計換熱網(wǎng)絡(luò )Uprogress in synthesis of heat exchanger network. Computers and節能技術(shù),2009,02:149-15Applied Chemistry, 2009, 26(10): 1315-13184 Linnhoff B and Eastwood(Member)AR Overall site optimisation8王志彬.煉油廠(chǎng)蒸餾裝置換熱網(wǎng)絡(luò )的綜合、調優(yōu)及其評價(jià)[Dby Pinch Technology Chemical Engineering Research and Design,鄭州大學(xué),20071997,75:138-1449高峰.夾點(diǎn)技術(shù)在苯乙烯裝置上的研究及應用[D].天津大學(xué),5 Liu Zhiyong, Li Zhiwei and Huo Lei. Pinch point theory and itsapplication in analysis of optimization of heat exchanger network200nergy Conservation Technology, 2012, 30(17): 273-277.10宋昌奇.夾點(diǎn)技術(shù)在石油化工中的應用D]西北工業(yè)大學(xué),6 Wang Chengyun. Process integration for energy saving andprocess pinch analysis China University of petroleum, 20117 Wang Rui, Fu Feng and Gao Xiaoming Optimization design of1l韓佳寶,采用夾點(diǎn)技術(shù)對玉米加工工藝換熱網(wǎng)絡(luò )優(yōu)化[D]哈heat transfer network by pinch technology. Energy Conservation爾濱工業(yè)大學(xué),2009echnology2009,02:149-153l2許剛VCM裝置的熱能夾點(diǎn)分析與優(yōu)化D]浙江大學(xué),20058 Wang Zhibin. Synthesis and evaluation of heat exchanger13黎軍.德土古水煤漿氣化工藝概況門(mén)、安徽化工,2001,networks for crude oil discuss plants. Zhenzhou University, 2007.9 Gao Feng. Pinch technology research and application in styreneuipment. Tianjin University, 200914張旭東,包宗宏.德士古水煤漿氣化裝置工程設計問(wèn)題探討門(mén)works. Nor&qi. Pinch technology application in petrochemical化學(xué)工業(yè)與工程技術(shù),2005,(0437-41,5811 Han Jiabao. Using pinch technology corn processing of network15肖杰飛,陳廣慶,級秋云QDB03催化劑在德士古水煤漿加壓for heat exchange optimize Harbin Institute of technology, 2009氣化高壓耐硫變換裝置上的應用[]化工設計通訊,201112 Xu Gang. Pinch analysis and optimization of vCm devices.37(2):75-7Zhejiang University, 2005Energy efficiency optimization of gasification and shift process in coal tomethanolQi Shaoning 1, Li Shiyu and Li Jinlai2(1. School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China)(2. ENN Research and Development Co Ltd, Langfang 065001, Hebei Province, China)Abstract: The energy efficiency of coal gasification and CO shift process of a 600 kt/a coal to methanol device was studied through pinchechnology. The results showed that the existing process had a huge energy saving potential because a great amount cross pinch heat transferxisted there. In order to recover high grade energy from this process, two suggested solutions were published in this paper. Solution 1reducing 0.3 Mpag steam by 53. 8%which is overproduction in current factory; increasing 1.2 Mpag steam by 6.5% and newly producing 2.5Mpag steam 18.83 MW. Solution 2: reducing 0.3 Mpag steam by 51.0 %and increasing 1. 2 Mpag steam by 22.2 % If the price differencebetween the 1.2 and 2.5 MPag steams is small and the equipment material is expensive, the soluti中國煤化工Keywords: pinch technology, heat exchanger network(HEN); coal gasification; shift process;CNMHGed:2013-1l-14)