- 期刊
林園廠三輕工場A-106去甲烷塔底部油料冷能回收利用與A-100塔蒸餾效率提昇
A Study of Recovery of Cooling Energy of the Bottom Product (C2 (superscript +)) of A-106 Demethanizer and Enhancement of Separation Efficiency of A-100 Wash Tower
摘要
在石化部各級長官指導下，三輕組、策略組、煉研所共同研究A-106去甲烷塔底部油料（C2（上標 +）冷媒）冷能回收利用與A-100塔蒸餾效率提昇。三輕日煉量乙烯為150萬磅，為Stone & Webster公司所設計，裂解區裂解氣壓縮機第四級出口之蒸汽產品，原設計係以Flash Drum分離，為增加分離效率，經修改Flash Drum為A-100蒸餾塔，此塔共有9層，其中精餾段塔徑7英呎，板距24 inch之閥板共有6板；汽提段為塔徑3英呎，板距7.5 inch之Baffle Tray共有3板，進料層為Chimney Tray。A-100 Wash Tower頂部產品C4（上標+）含量必須低於2.97 mole％，塔底產品C2（上標–）之含量必須低於29.7 mole％，以免影響下游Cold Box之操作。由於四輕同樣塔之精餾段共有10板，且A-100Wash Tower之蒸餾板之汽液流動面積必須重新設計，經模擬計算A-100塔在精餾段可以增加5板，變為11板；汽提段可以增加1板，變為4板。A-100塔增加回流量，可以提昇A-100塔之分離效率，但會增加T-109冷凝器之冷媒（丙烯）冷能耗用；經評估增加一座新冷凝器（T-109A），經與三輕組、策略組討論，認為可以比照四輕工場採用去甲烷塔（A-106）底部油料冷媒（C2（上標+））做冷媒，將冷能回收。經石化部策略組、三輕組、工務組、修護組、煉研所經數次開討論與規劃，包括製程模擬、新冷凝器（T-109A）設計、管線放大設計、A-100塔更換塔盤設計、控制閥設計、新幫浦設計、設備採購，設備安裝、設備安檢。三輕於96年10月大修時，安裝新冷凝器（T-109A）、A-100塔新塔盤、新控制閥、新管線、新幫浦等。三輕於96/11/23開俥，A-100塔之操作正常，去甲烷塔（A-106）底部油料（C2（上標+））開始冷能回收，使T-109 冷凝器之丙烯冷媒之使用量由大修前30,000～60,000 LB／HR降至大修後20,000～45,000 LB／HR；以致丙烯壓縮機之高壓蒸汽使用量大為減少。為比較更改製程前後之節能效益，計算高壓蒸汽使用量減少所產生之效益如下：第一次節能效益計算（96年11月～97年6月）修改製程前（96年1～10月）每磅輕油進料量之高壓蒸汽使用量為1.0449磅，修改製程後（96年11月～97年6月）每磅輕油進料量之高壓蒸汽使用量為0.822磅，減少了0.2229磅、高壓蒸汽量平均價格0.776元／磅、輕油進料總量為956,872,609磅、高壓蒸汽使用量減少了213,498,526磅、高壓蒸汽使用量減少之效益為165,674,856元（亦即操作8個月之效益約1億6,500萬元）。第二次節能效益計算（97年7月至98年6月）修改製程前（96年1～10月）每磅輕油進料量之高壓蒸汽使用量為1.0449磅，修改製程後（97 年7 月～98 年6 月）每磅輕油進料量之高壓蒸汽使用量為0.858 磅，減少了0.1869磅、高壓蒸汽量平均價格0.780元／磅、輕油進料總量為1,185,915,268磅、高壓蒸汽使用量減少了221,106,392磅、高壓蒸汽使用量減少之效益為172,411,205元（亦即操作12個月之效益約1億7,200萬元）。第三次節能效益計算（98年7月至99年6月）修改製程前（96年1至10月）每磅輕油進料量之高壓蒸汽使用量為1.0449磅，修改製程後（98年7月至99 年6月）每磅輕油進料量之高壓蒸汽使用量為0.895磅，減少了0.149磅、輕油進料總量為1,328,001,674磅、高壓蒸汽使用量減少了198,731,111磅、高壓蒸汽量平均價格0.65元／磅，故高壓蒸汽使用量減少之效益為129,175,222（亦即操作12個月之效益約1億2,900萬元）。操作三年節省操作成本共467,261,283元（即4億6,700萬元）。
並列摘要
The Petrochemical Business Division and Refining & Manufacture of Research Institute studied together in the recovery of the cooling energy of the bottom product (C2(superscript +)) of A-106 demethanizer and the enhancement of separation efficiency of A-100 wash tower. The capacity of No.3 Cracking unit is 1,500,000 pounds/day of ethylene designed by Stone & Webster Company. The cracking vapor product that removed at the 4th stage of compressor was fed into A-100 wash tower. The A-100 wash tower was equipped 6 trays at the rectifying section and 3 trays at the stripping section. The C4(superscript +)content of the lighter components removed at the top of A-100 wash tower must be less than 2.97 mole %. The C2(superscript -)content of heavier components removed at the bottom of A-100 wash tower must be less than 29.7 mole %. The simulation of A-100 wash tower exhibited that A-100 wash tower was allowed increasing 5 trays at the rectifying section and allowed increasing 1 tray at the stripping section. To increase the reflux rate will enhance the separation efficiency of A-100 wash tower, which will increase the usage of coolant (propylene) of T-109 condenser though. Alternately, installing a new condenser (T-109A) with the utilization of the C2(superscript +) product withdrew at bottom of A-106 demethanizer offered some advantages since the cooling energy of the bottom product (C2(superscript +)) of A-106 demethanizer can be recovered and the reflux rate of A-100 wash tower can be increased. This revamping project included doing process simulation, designing T-109A condenser, sizing the pipes, replacing new trays at A-100 wash tower, designing new control valves and pumps, doing equipments procurement, installing new equipments and inspecting the safety of equipments. The new equipments were installed during the turnaround period of No.3 Cracking unit in October 2007. No.3 Cracking unit started up on 23th, November, 2007 and it has been operating successfully. The cooling energy of the bottom product (C2(superscript +)) of A-106 demethanizer was recovered efficiently. The usage of the coolant (propylene) of the T-109 condenser decreased significantly. The consumption of the high pressure steam driving the propylene compressors was decreased significantly. To demonstrate how successful of this project, the benefit calculation is illustrated as follows. The 1st phase calculation of the benefit (November, 2007 to June, 2008) The consumption of high-pressure steam was 1.0449 Lbs/Lb-naphtha feedstock before doing this revamping project. The consumption of high-pressure steam was 0.822 Lbs/Lbnaphtha feedstock after this revamping project (November, 2007 to June, 2008), reduced by 0.2229 pounds. The average price of high-pressure steam during this period was NT$0.776/Lb. The total amount of the charging naphtha feedstock during this period was 956,872,609 Lbs. The benefit stemming from the reduction of the consumption of highpressure steam during this period was NT$165,674,856. The 2nd phase calculation of the benefit (July, 2008 to June, 2009) The consumption of high-pressure steam was 1.0449 Lbs/Lb-naphtha feedstock before this revamping project. The consumption of high-pressure steam was 0.858 Lbs/Lb-naphtha feedstock after this revamping project (July, 2008 to June, 2009), reduced by 0.1869 pounds. The average price of high-pressure steam during this period was NT$0.780/Lb. The total amount of the charging naphtha feedstock during this period was 1,185,915,268 Lbs. The benefit stemming from the reduction of the consumption of high-pressure steam during this period was NT$172,411,205. The 3th phase calculation of the benefit (July, 2009 to June, 2010) The consumption of high-pressure steam was 1.0449 Lbs/Lb-naphtha feedstock before this revamping project. The consumption of high-pressure steam was 0.895 Lbs/Lb-naphtha feedstock after this revamping project (July, 2009 to June, 2010), reduced by 0.149 pounds. The average price of high-pressure steam during this period was NT$0.650/Lb. The total amount of the charging naphtha feedstock during this period was 1,328,001,674 Lbs. The benefit stemming from the reduction of the consumption of high-pressure steam during this period was NT$129,175,222.