1242599 A7 B7 五、發明説明（1 ) 技術領域 本發明爲一種抽提蒸餾方法從烴類混合物中分離芳烴 所用的複合溶劑。 (請先閲讀背面之注意事項再填寫本頁) 背景技術 從彳隹化重整汽油或裂解加氫汽油等烴類混合物中分離 芳烴的方法主要有液液抽提法和抽提蒸餾法。液液抽提法 應用最廣的選擇性溶劑爲甘醇類或環丁硕。液液抽提雖能 以較尚收率獲得尚純度苯、甲苯及二甲苯（BTX)產品， 但現有的液液抽提方法適用於處理芳烴含量爲3〇〜7〇重量 %的原料，對於方含大於7 0重量％的原料，則需與抽餘油 混兌，使能耗增高，裝置效率降低。 經濟部智慈財產局員工消費合作社印製 抽提蒸餾是利用溶劑對烴類各組份相對揮發度影響的 不同而從烴類混合物中分離芳烴的方法。在處理高芳烴原 料時，無須進行抽餘油混兌，所用溶劑一般爲單純的N-甲醯 基嗎啉、N-甲基吡咯烷酮、環丁硕等。如US纟，3 1 0,480提 出了一種抽提蒸f留分離芳烴的方法，僅使用一個含有再沸 器的塔及旋風分離器將原料中的芳烴和非芳烴分離，所述 塔的上段用於抽提蒸餾，下段用於回收溶劑。爲提高選擇 性、降低溶劑回收的苛刻度，在環丁硕衍生物、甘醇、甘 醇醚等選擇性溶劑中加入〇.丨〜2〇重量％的水，且溶劑回收 過程借助於水蒸汽汽提。該專利提到芳烴選擇性溶劑可以 是複合溶劑，其中一種組份爲低分子量的聚亞烷基甘醇， 另一種組份爲甘醇醚，兩種組份的互溶量爲0.1〜99重量％ 本紙張尺度適用中國國家標準（CNS ) A4規格（210X 297公釐） -5- 1242599 Α7 Β7 五、發明説明（2 ) (請先閱讀背面之注意事項再填寫本頁) 。該法由於在溶劑中加水和使用汽提回收溶劑，使抽提蒸 飽得到的芳烴因含水而不能直接作爲產品，尙需進一步精 鶴。由於受含水溶劑溶解性的限制，抽提蒸餾芳烴含量較 低的原料時，容易在抽提蒸餾塔內形成兩個液相，影響操 作控制。另外，系統含有的水易造成設備腐蝕。 CN 1 262264A公開了一種抽提蒸餾和液液抽提組合方 法，該方法將原料預分餾得到含苯的第一餾份以及含少量 苯的第二餾份，第一餾份進行抽提蒸餾得本產品；第二餾 份和抽提蒸餾操作得到的抽餘油混合後進行液液抽提得到 甲苯和少量的苯。該方法對原料限制較小，適用範圍寬， 操作能耗低，並能同時回收B TX，適合於煉廠原有抽提裝 置的擴建改造。該專利在抽提蒸餾分離苯的選擇性溶劑中 加入0. 1〜1 5重量％的C 8〜C μ芳烴作爲助溶劑來增加溶劑的 溶解性，由於溶劑和系統中均不含水，從而避免了水對回 收苯造成的不利影響。但該專利僅對鄰二甲苯作爲助溶劑 的情況進行了具體實施應用，並且局限在組合方法的抽提 蒸餾操作中。 經濟部智慧財產局員工消費合作社印製 現有使用單一抽提蒸餾溶劑的方法，在溶劑回收過程 中，由於受到溶劑熱分解溫度的限制，回收塔溫度不能太 高，因此需要提高真空度以保證將富溶劑中的溶劑與芳烴 徹底分離，回收塔操作苛刻度因而較高。此外，由於要求 抽提蒸餾溶劑有一定的極性，以增強對芳烴的選擇溶解性， 其結構中往往含有〇、Ν、s等原子，因而帶有一定的弱 酸性或弱鹼性，這使得抽提蒸餾後的芳烴產品也帶有相應 本紙張尺度適用中國國家標準（CNS ) Α4規格（210X297公釐） -6- 1242599 A7 B7 五、發明説明（3 ) 的弱酸性或弱鹼性，產品不得不進行後處理，脫除酸性或 鹼性。 (請先閲讀背面之注意事項再填寫本頁) 發明槪述 本發明的目的在於提出一種性能更好的用於抽提蒸餾 分離芳烴方法的複合溶劑，該複合溶劑具有較大的溶解性 和相對較寬的沸點範圍，可緩和溶劑回收操作的條件，減 少能耗。 附圖說明 圖1爲應用本發明複合溶劑的抽提蒸餾操作流程簡圖 〇 發明詳述 經濟部智慈財產局員工消費合作社印製 本發明所述的複合溶劑，包括主溶劑和助溶劑，還有 改性劑，所述的助溶劑選自C8〜Cll芳烴中的任意一種或兩 種具有不同碳數芳烴的混合物，其含量爲3〜39重量％， 且助溶劑中最小芳烴的碳數應大於欲分離芳烴中最大芳烴 的碳數；當助溶劑選自C8〜Cm芳烴中的任意一種時，複 合溶劑中含有〇. 〇 1〜1 〇· 〇重量％的改性劑，當助溶劑選自 0〜1 0. 0重量％的改性劑，所述的主溶劑和改性劑分別選自 環丁碼、N -甲醯基嗎啉或N -甲基吡咯烷酮，條件是改性 劑酸鹼性與主溶劑相反。 本發明的主劑和改性劑可選自環丁硕衍生物、N_甲醯 本紙張尺度適用中國國家標準（CNS ) A4規格（2IOX 297公釐） 1242599 A7 ----- - B7 五、發明説明（4 ) ^ - 基嗎啉或N_甲基批略烷酮，所述的環丁硕衍生物係如下 通式所示：1242599 A7 B7 V. Description of the Invention (1) Technical Field The present invention is a composite solvent used in an extractive distillation method to separate aromatics from a hydrocarbon mixture. (Please read the precautions on the reverse side before filling out this page) Background Technology The methods for separating aromatics from hydrocarbon mixtures such as tritiated reformed gasoline or cracked hydrogenated gasoline include liquid-liquid extraction and extractive distillation. Liquid-liquid extraction methods The most widely used selective solvents are glycols or cyclidine. Although liquid-liquid extraction can obtain high-purity benzene, toluene, and xylene (BTX) products at relatively high yields, the existing liquid-liquid extraction method is suitable for processing raw materials with an aromatic content of 30 to 70% by weight. If the square contains more than 70% by weight of raw materials, it must be mixed with the residual oil to increase energy consumption and reduce the efficiency of the device. Printed by the Employees' Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs. Extractive distillation is a method for separating aromatics from hydrocarbon mixtures by taking advantage of the different effects of solvents on the relative volatility of various hydrocarbon components. When processing high aromatics raw materials, there is no need to carry out raffinate blending, and the solvents used are generally simple N-formamylmorpholine, N-methylpyrrolidone, cyclobutane, and the like. For example, US Pat. No. 3,0,480 proposes a method for extracting and separating aromatics by distillation and distillation. Only a tower containing a reboiler and a cyclone are used to separate aromatics and non-aromatic hydrocarbons in the raw material. The upper stage of the tower is used for Extractive distillation, the lower stage is used to recover the solvent. In order to improve the selectivity and reduce the harsh scale of solvent recovery, 0.1 to 20% by weight of water is added to selective solvents such as cyclobutan derivatives, glycols, and glycol ethers, and the solvent recovery process is aided by steam Stripping. The patent mentions that the aromatic selective solvent can be a composite solvent, one of which is a low molecular weight polyalkylene glycol, and the other is a glycol ether, and the mutual solubility of the two components is 0.1 to 99% by weight. This paper size applies to Chinese National Standard (CNS) A4 specification (210X 297 mm) -5- 1242599 Α7 Β7 V. Description of invention (2) (Please read the precautions on the back before filling this page). In this method, due to the addition of water to the solvent and the use of stripping to recover the solvent, the aromatic hydrocarbons obtained by extraction and evaporation cannot be directly used as products due to water content, so further refinement is required. Due to the limitation of the solubility of the aqueous solvent, when extracting the raw materials with low aromatics content, it is easy to form two liquid phases in the extractive distillation column, which affects the operation control. In addition, the water contained in the system can easily cause equipment corrosion. CN 1 262264A discloses a combined method of extractive distillation and liquid-liquid extraction. This method pre-fractionates raw materials to obtain a first fraction containing benzene and a second fraction containing a small amount of benzene. This product; the second fraction is mixed with the raffinate oil obtained by the extractive distillation operation, and liquid-liquid extraction is performed to obtain toluene and a small amount of benzene. This method has less restrictions on raw materials, wide application range, low operating energy consumption, and can recover B TX at the same time, which is suitable for the expansion and reconstruction of the original extraction equipment of the refinery. The patent adds 0.1 ~ 1 5 wt% C 8 ~ C μ arene as a co-solvent in a selective solvent for extracting and separating benzene to increase the solubility of the solvent. Since neither the solvent nor the system contains water, it avoids The adverse effects of water on the recovery of benzene. However, this patent only specifically implements the application of o-xylene as a co-solvent, and is limited to the extraction and distillation operation of the combined method. The Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs printed the existing method using a single extraction distillation solvent. During the solvent recovery process, the temperature of the recovery tower cannot be too high due to the limitation of the thermal decomposition temperature of the solvent, so the vacuum degree needs to be increased to ensure that The solvent in the rich solvent is completely separated from the aromatic hydrocarbon, and the recovery column is operated with a high degree of severity. In addition, because the extraction distillation solvent is required to have a certain polarity to enhance the selective solubility of aromatic hydrocarbons, its structure often contains atoms such as 0, N, and s, so it has a certain weak acidity or basicity, which makes the extraction The distilled aromatic products also have the corresponding paper size applicable to the Chinese National Standard (CNS) A4 specifications (210X297 mm) -6- 1242599 A7 B7 V. The description of the invention (3) is weakly acidic or alkaline, the product must not be Without post-treatment, remove acidity or alkalinity. (Please read the notes on the back before filling this page) Description of the invention The purpose of the present invention is to propose a composite solvent with better performance for the method of extractive distillation and separation of aromatics. The composite solvent has greater solubility and relative The wide boiling point range can ease the conditions of solvent recovery operation and reduce energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of an extraction distillation operation process using the composite solvent of the present invention. Detailed description of the invention The composite solvent according to the present invention printed by the consumer cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs includes the main solvent and the co-solvent. With a modifier, the co-solvent is selected from any one of C8 ~ Cll aromatics or a mixture of two aromatics having different carbon numbers, and the content is 3 to 39% by weight, and the carbon number of the smallest aromatic hydrocarbon in the co-solvent should be Carbon number greater than the maximum aromatics in the aromatics to be separated; when the co-solvent is selected from any of C8 ~ Cm aromatics, the composite solvent contains 0.001 ~ 1 〇 · ％ by weight of the modifier, when the co-solvent is selected From 0 to 10.0% by weight of a modifier, the main solvent and the modifier are selected from cyclobutane, N-formylmorpholine or N-methylpyrrolidone, provided that the modifier acid Basicity is the opposite of the main solvent. The main agent and modifier of the present invention may be selected from the group consisting of cyclidine derivatives and N-formamidine. The paper size is applicable to Chinese National Standard (CNS) A4 specification (2IOX 297 mm) 1242599 A7 ------B7. 2. Description of the invention (4) ^-morpholine or N-methylpyrrolidone, the cyclobutane derivative is shown by the following general formula:
j裝-- (請先閱讀背面之注意事項再填寫本頁) 式中Ri、R2、R3、R4分別選自氫、匕〜。。的烷基、 C7〜Cu的芳烷基、Cl〜C8的烷氧基。較佳的溶劑是環丁硕 ' 2、甲基環丁硕或2，4 -二甲基環丁硕。 4 本發明複合溶劑中的助溶劑具有增溶作用，其選用應 根據欲分離芳烴的組成進行，也就是說，助溶劑要有與欲 分離芳烴相似的結構，以增強對芳烴的溶解性，但助溶劑 又要區別於所分離的芳烴，以便於溶劑回收。一般含芳烴 的原料中都含有苯和甲苯，所以，助溶劑可選自.c8〜Cll芳 烴中的任意一種或兩種的混合物，但當分離原料中有二甲 苯時，助溶劑應選c9以上的芳烴，宜爲C9芳烴或c9與 c 1。芳烴的混合物。 經濟部智慧財產局員工消費合作社印製 複合溶劑中加入改性劑可改善由主溶劑造成的分離芳 烴偏離中性的問題，如使用環丁硕爲主溶劑時，由於其本 身呈現弱酸性，致使分離的芳烴產品也呈弱酸性，產品需 要後處理以中和其酸性，同理，若用呈弱鹼性的N -甲醯 基嗎啉或N -甲基吼略院酮爲主溶劑，則分離產品呈弱驗 性，產品需要進行酸處理以中和其鹼性。若在複合溶劑中 加入一種與主溶劑酸鹼性相反的抽提溶劑作改性劑即可使 分離的芳烴產品呈中性而省去後處理步驟。具體地說，環 本纸張尺度適用中國國家標準（CNS ) A4規格（210X297公釐） -8- 1242599 kl ___ B7 五、發明説明（5 ) 丁硕爲主溶劑時，改性劑選自N -甲醯基嗎啉或N -甲基吡 咯烷酮；主溶劑爲N -甲醯基嗎啉或n -甲基吡咯烷酮時， 改性劑爲環丁硕。 當助溶劑選自C8〜Cu芳烴中的任意一種時，任意一種 芳烴指具有相同碳數的芳烴或同分異構體的混合物，如 Cs芳烴包括鄰二甲苯、間二甲苯 '對二甲苯、乙苯或混 D —甲本，C9方烴包括異丙苯、三甲基苯等，複合溶劑中 助溶劑含量宜爲5〜3 0重量％，改性劑的含量宜爲〇.丨〜5 . 〇 重量％。 當所述的助溶劑選自C8〜Ch芳烴中任意兩種具有不 同碳數芳烴的混合物時，複合溶劑中助溶劑的含量宜爲 5〜30重量％，改性劑的含量宜爲〇〜5〇重量％，更宜爲 0 · 1〜5.0重量％。所述的助溶劑中任意兩種碳數不同的芳烴 混合物宜爲C8 + n芳烴與C9”芳烴的混合物，η爲0、1或2, 其中C“n/C9 + n芳烴的重量比爲1〜5〇:1，宜爲1〜20:1，更宜 爲 1· 5〜15.0:1 。 本發明複合溶劑適用於抽提蒸餾操作過程，適宜的抽 fee蒸態原料爲裂解加氨方法的汽油|留份、重整生成油、煤 焦油，原料中的芳烴含量爲15〜99重量％，原料最好是含 一種芳烴或兩種芳烴的烴類混合物，如原料中含苯、苯與 甲苯或甲苯與二甲苯。 應用本發明提供的複合溶劑進行抽提蒸餾分離芳烴的 方法包括：將複合溶劑從抽提蒸餾塔的上部引入，烴類混 合物自抽提蒸餾塔的中部引入塔中，經過抽提蒸餾，非芳 本紙張尺度適用中國國家標準（CNS ) A4規格（210X 297公釐） (請先閲讀背面之注意事項再填寫本頁)J equipment-(Please read the notes on the back before filling this page) where Ri, R2, R3, R4 are selected from hydrogen and dagger ~. . Alkyl, C7 ~ Cu aralkyl, Cl ~ C8 alkoxy. The preferred solvent is cyclodine, 2, methylcyclodine, or 2,4-dimethylcyclodine. 4 The co-solvent in the composite solvent of the present invention has a solubilizing effect, and its selection should be based on the composition of the aromatics to be separated, that is, the co-solvent must have a structure similar to the aromatics to be separated to enhance the solubility of the aromatics, but The co-solvent should be distinguished from the aromatics separated to facilitate solvent recovery. Generally, aromatics-containing raw materials contain benzene and toluene, so the co-solvent can be selected from any one or a mixture of .c8 ~ Cll aromatics, but when xylene is included in the separation raw material, the co-solvent should be selected to be c9 or higher. The aromatic hydrocarbon is preferably a C9 aromatic hydrocarbon or c9 and c 1. Aromatic mixture. The addition of modifiers to the composite solvents printed by the employees' cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs can improve the separation of aromatics from neutrality caused by the main solvent. For example, when cyclodine is used as the main solvent, due to its weak acidity, The isolated aromatics product is also weakly acidic. The product needs to be post-treated to neutralize its acidity. Similarly, if N-methylamidomorpholine or N-methyl cyproterone is used as the main solvent, then The isolated product is weakly sensitive and the product needs to be acid treated to neutralize its alkalinity. Adding an extraction solvent opposite to the acidity and basicity of the main solvent as a modifier in the composite solvent can make the separated aromatic product neutral and eliminate the post-treatment step. Specifically, the size of the paper is applicable to the Chinese National Standard (CNS) A4 (210X297 mm) -8-1242599 kl ___ B7 V. Description of the invention (5) When Ding Shuo is the main solvent, the modifier is selected from N -Formamylmorpholine or N-methylpyrrolidone; when the main solvent is N-formamylmorpholine or n-methylpyrrolidone, the modifier is cyclobutane. When the co-solvent is selected from any one of C8 ~ Cu aromatic hydrocarbons, any aromatic hydrocarbon refers to an aromatic hydrocarbon or a mixture of isomers having the same carbon number. For example, Cs aromatic hydrocarbons include o-xylene, m-xylene, p-xylene, Ethylbenzene or mixed D-formyl, C9 side hydrocarbons include cumene, trimethylbenzene, etc. The co-solvent content in the composite solvent should be 5 ~ 30% by weight, and the content of the modifier should be 〇. 丨 ~ 5 〇wt%. When the co-solvent is selected from a mixture of any two aromatic hydrocarbons having different carbon numbers in C8 ~ Ch aromatics, the content of the co-solvent in the composite solvent is preferably 5 to 30% by weight, and the content of the modifier is preferably 0 to 5 〇wt%, more preferably from 0.1 to 5.0wt%. Any two aromatic hydrocarbon mixtures with different carbon numbers in the co-solvent are preferably a mixture of C8 + n aromatics and C9 ”aromatics, η is 0, 1 or 2, wherein the weight ratio of C” n / C9 + n aromatics is 1 ~ 5〇: 1, preferably 1 ~ 20: 1, more preferably 1.5 ~ 15.0: 1. The composite solvent of the present invention is suitable for the extraction and distillation operation process. The suitable steamed raw material for extraction is gasoline for the pyrolysis and ammonia method. Residue, reformed oil, and coal tar. The aromatic content in the raw material is 15 to 99% by weight. The raw material is preferably a hydrocarbon mixture containing one aromatic hydrocarbon or two aromatic hydrocarbons, such as benzene, benzene and toluene or toluene and xylene in the raw material. The method for extracting and distilling aromatics by applying the composite solvent provided by the present invention includes: introducing the composite solvent from the upper part of the extractive distillation column, and introducing the hydrocarbon mixture into the column from the middle of the extractive distillation column. Paper size applies Chinese National Standard (CNS) A4 (210X 297 mm) (Please read the precautions on the back before filling this page)
、11 經濟部智慈財產局員工消費合作社印製 -9- 1242599 A7 B7 五、發明説明（7) 4及溶劑回收塔1 2塔底均設有再沸器1 0、1 9。 對於用抽提蒸餾同時回收苯/甲苯的情況，原料爲 〜C?餾份，流程與上述流程一樣，只是從回收塔頂得到 的是苯/甲苯的混合物。該混合物通過進一步的精餾分離， 即可獲得純苯和純甲苯。對於從C8餾份中分離二甲苯的 情況，其操作與回收苯的情況一致，但使用的助溶劑應爲 C9以上的芳烴，。對於同時回收甲苯/二甲苯的情況，其操 作與同時回收苯/甲苯的情況相似，只是所用助溶劑應爲 C9以上的芳烴。 本發明複合溶劑由於助溶劑的加入，顯著增加了溶劑 的溶解能力，使複合溶劑用於從芳烴含量較低原料回收芳 烴時，仍具有足夠高的芳烴回收率，因而擴大了裝置的適 用範圍；助溶劑的加入還可大大緩和溶劑回收塔的操作 條件，減少溶劑熱分解產生的硫、氮、氧等有害雜質對產 品質量的影響。此外，改性劑的加入可保證芳烴產品呈中 性，減少後處理步驟。 本發明複合溶劑不含水，溶劑回收塔也不含汽提水， 因而可直接得到芳烴產品，不需另建水分離設備，不僅節 省了投資和能耗，還可免除水對操作設備造成的腐蝕。 下面通過實施例進一步說明本發明，但本發明並不限 於此。 實施例1 從裂解加氫汽油苯餾份中回收苯，所用原料組成見表 本紙張尺度適用中國國家標準（CNS ) A4規格（210X297公釐） --------.#壯衣-- -- (請先閲讀背面之注意事項再填寫本頁) -一口 •1% 經濟部智慈財產局8工消費合作社印製 1242599 A7 ' _B7_2- · 五、發明説明（8 ) - (請先閱讀背面之注意事項再填寫本頁) 2，採用的複合溶劑組成爲：以環丁硕爲主溶劑，鄰二甲苯 和異丙苯的混合物爲助溶劑，改性劑爲N-甲醯基嗎啉， 複合溶劑中各組份的含量列於表1。採用圖1所示的工 流程，抽提蒸餾塔、溶劑回收塔的操作條件見表3，芳V 分離結果見表4。 實施例2 從重整生成油C6餾份中回收苯產品，仍採用圖1的 操作流程。複合溶劑的主溶劑爲環丁硕，助溶劑爲鄰二甲 苯和異丙苯，改性劑爲N-甲基吡咯烷酮，其組成見表i， 原料組成列於表2，抽提蒸餾塔、溶劑回收塔的操作條件 見表3，芳烴分離結果見表4。 由表3、表4數據可知，對於芳烴含量比較低的重整 生成油，採用本發明之的複合溶劑進行抽提蒸餾，在回收 塔操作條件較爲緩和的情況下，不僅可以非常穩定地操作 和控制，而且能以99.6%的高回收率獲取純度爲99.98 %、 硫含量爲0· 2ppm的苯產品，抽餘油中芳烴含量也很低， 僅爲0.3 2 %。 經濟部智慧財產局員工消費合作社印製 實施例3 從裂解加氫汽油苯餾份中回收苯，所用原料和操作條 件均同實施例1,不同的是複合溶劑的主溶劑爲環丁硕， 助溶劑爲鄰二甲苯和異丙苯，未加改性劑，其組成見表1， 芳烴分離結果見表4。 本紙張尺度適用中國國家標準（CNS ) A4規格（210X 297公釐） -12- 1242599 A7 B7 五、發明説明（9 ) 實施例4 從裂解加氫汽油苯餾份中回收苯，所用原料和操作條 件均同實施例1，不同的是複合溶劑的主溶劑爲環丁硕， 助溶劑爲鄰二甲苯，改性劑爲N_甲醯基嗎啉，其組成見 表1，芳烴分離結果見表4。 比較例 從裂解加氫汽油苯餾份中回收苯，所用原料和操作條 件均同實施例1，不同的是使用CN 1 262264A所述以環丁 硕爲主溶劑，鄰二甲苯爲助溶劑的複合溶劑，其組成見表 1，抽提蒸餾塔、溶劑回收塔的操作條件見表3，芳烴分 離結果見表4。 由表4所示的實施例3和比較例的數據可知，本發明 選用的含二種組份助溶劑的複合溶劑與CN 1 262264A使用 的含單一組份助溶劑的複合溶劑相比，在操作參數相當的 條件下，可提高苯產品收率。實施例4的數據說明在複合 溶劑中加入改性劑，可使苯產品中硫含量降低，達到中性 試驗要求。而實施例1 - 2的數據顯示，含兩種組份助溶劑 和改性劑的複合溶劑，具有更好的效果，不僅可提高芳烴 收率，還能降低硫含量，苯產品爲中性。中性的苯產品可 不必通過後處理來脫除產品的微量酸性物質，從而簡化流 程。 實施例5 本紙張尺度適用中國國家標準（CNS ) A4規格（210X 297公釐） (請先閱讀背面之注意事項再填寫本頁)11 Printed by the Consumer Cooperative of the Intellectual Property Office of the Ministry of Economic Affairs -12-12599 A7 B7 V. Description of Invention (7) 4 and Solvent Recovery Tower 12 Both bottoms are equipped with reboilers 10 and 19. For the case where benzene / toluene is recovered by extractive distillation at the same time, the raw material is a ~ C? Fraction. The process is the same as the above process, except that a benzene / toluene mixture is obtained from the top of the recovery column. The mixture is separated by further distillation to obtain pure benzene and pure toluene. For the separation of xylene from the C8 fraction, the operation is the same as that for the recovery of benzene, but the co-solvent used should be an aromatic hydrocarbon of C9 or higher. In the case of simultaneous recovery of toluene / xylene, the operation is similar to the case of simultaneous recovery of benzene / toluene, except that the co-solvent used should be an aromatic hydrocarbon of C9 or higher. The compound solvent of the present invention significantly increases the solubility of the solvent due to the addition of a co-solvent, so that when the compound solvent is used to recover aromatics from a raw material with a low aromatic content, the aromatic solvent still has a sufficiently high aromatics recovery rate, thereby expanding the scope of application of the device; The addition of a co-solvent can also greatly ease the operating conditions of the solvent recovery tower and reduce the impact of sulfur, nitrogen, oxygen and other harmful impurities on the product quality caused by the thermal decomposition of the solvent. In addition, the addition of modifiers can ensure that aromatic products are neutral and reduce post-treatment steps. The composite solvent of the present invention does not contain water, and the solvent recovery tower does not contain stripping water, so that aromatic products can be directly obtained without the need to separately construct water separation equipment, which not only saves investment and energy consumption, but also avoids the corrosion of operating equipment caused by water . The present invention is further illustrated by the following examples, but the present invention is not limited thereto. Example 1 Benzene was recovered from the benzene fraction of cracked hydrogenated gasoline. The composition of the raw materials is shown in the table. The paper size is applicable to the Chinese National Standard (CNS) A4 specification (210X297 mm) --------. # 壮 衣- --(Please read the notes on the back before filling this page)-sip • 1% Printed by the 8th Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs 1242599 A7 '_B7_2-· V. Description of Invention (8)-(Please first Read the notes on the reverse side and fill in this page) 2. The composition of the compound solvent used is: cyclobutanol as the main solvent, a mixture of o-xylene and cumene as the co-solvent, and the modifier is N-formamyl. The content of each component in the chlorophene and composite solvents is shown in Table 1. Using the process shown in Figure 1, the operating conditions of the extraction distillation column and solvent recovery column are shown in Table 3, and the separation results of aromatic V are shown in Table 4. Example 2 The benzene product was recovered from the C6 fraction of the reformed oil, and the operation flow of Fig. 1 was still used. The main solvent of the composite solvent is cyclobutane, the co-solvents are o-xylene and cumene, and the modifier is N-methylpyrrolidone. Its composition is shown in Table i. The raw material composition is shown in Table 2. The extraction distillation column, solvent The operating conditions of the recovery column are shown in Table 3, and the results of aromatics separation are shown in Table 4. From the data in Tables 3 and 4, it can be known that, for the reformed oil with a relatively low aromatic content, the composite solvent of the present invention is used for extractive distillation, and the operation conditions of the recovery column are relatively mild, which not only can be operated very stably And control, and can obtain a benzene product with a purity of 99.98% and a sulfur content of 0.2 ppm with a high recovery rate of 99.6%. The aromatics content in the raffinate is also very low, only 0.3 2%. Printed in Example 3 by the Consumers' Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs. Benzene was recovered from the benzene fraction of cracked hydrogenated gasoline. The raw materials and operating conditions were the same as in Example 1. The difference was that the main solvent of the composite solvent was cyclidine. The solvents are o-xylene and cumene, no modifier is added, the composition is shown in Table 1, and the results of aromatics separation are shown in Table 4. This paper size applies Chinese National Standard (CNS) A4 specification (210X 297 mm) -12- 1242599 A7 B7 V. Description of the invention (9) Example 4 Recovering benzene from benzene fraction of cracked hydrogenated gasoline, raw materials and operation The conditions are the same as in Example 1. The difference is that the main solvent of the composite solvent is cyclidine, the co-solvent is o-xylene, and the modifier is N-methylamidomorpholine. Its composition is shown in Table 1. The results of the aromatics separation are shown in Table. 4. Comparative Example Benzene was recovered from the benzene fraction of cracked hydrogenated gasoline. The raw materials and operating conditions were the same as in Example 1. The difference was that the compound described in CN 1 262264A was cyclobutane-based and o-xylene was used as a co-solvent. The composition of the solvent is shown in Table 1. The operating conditions of the extraction distillation column and the solvent recovery column are shown in Table 3. The results of the aromatics separation are shown in Table 4. According to the data of Example 3 and Comparative Example shown in Table 4, it can be seen that the composite solvent containing two component cosolvents used in the present invention is compared with the composite solvent containing a single component cosolvent used in CN 1 262264A. Under the same conditions, the yield of benzene products can be improved. The data of Example 4 shows that adding a modifier to the composite solvent can reduce the sulfur content in the benzene product and meet the requirements of the neutral test. The data of Examples 1-2 show that a composite solvent containing two component co-solvents and modifiers has better results, which can not only improve the yield of aromatics, but also reduce the sulfur content. The benzene product is neutral. Neutral benzene products eliminate the need for post-treatment to remove traces of acidic products, simplifying the process. Example 5 This paper size applies the Chinese National Standard (CNS) A4 specification (210X 297 mm) (Please read the precautions on the back before filling this page)
、1T 經濟部智慧財產局員工消費合作社印製 -13- 1242599 A7 B7 五、發明説明（1〇) 從裂解加氫汽油C6〜C7 f留份中同時回收苯、甲苯產品 。抽提蒸餾部分採用圖1所示的流程，得到的苯/甲苯混 合物進入精餾塔通過精餾分離成爲苯、甲苯產品。抽提蒸 I留採用的複合溶劑以N -甲醯基嗎啉爲主溶劑，助溶劑爲 二甲苯和異丙苯，改性劑爲環丁硕，其組成見表1，所用 原料組成見表4，抽提蒸餾塔、溶劑回收塔的操作條件見 表3，芳烴分離結果見表5。 由表3、表5數據可知，在溶劑回收塔塔頂殘壓爲 0.04 5MPa，塔頂72°C、塔底186°C的相對緩和的操作條件 下，可獲得純度爲9 9 · 9 %的苯/甲苯混合芳烴，且產品爲中 性，精餾分離之後得到的苯和甲苯產品分別滿足G B 3 4 0 5 -8 9和G B 3 4 0 6 - 9 0的國家優級標準。若採用單純的n -甲醯 基嗎啉爲抽提蒸餾溶劑，達到同樣的芳烴純度和收率時， 回收塔的殘壓要0.03 8MPa，塔底溫度要2〇1。(：，且混合芳 烴中含量將局達2〜3ppm，這會使甲苯產品中氮量嚴重偏 高，呈較強鹼性，要採用白土吸附精製等產品後處理措施 使產品爲中性。 (請先閱讀背面之注意事項再填寫本頁)Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs of the 1T. -13- 1242599 A7 B7 V. Description of the invention (10) Benzene and toluene products are simultaneously recovered from the cracked hydrogenated gasoline C6 ~ C7 f. The extractive distillation part adopts the flow shown in Figure 1. The benzene / toluene mixture obtained enters the rectification column and is separated into benzene and toluene products by rectification. The compound solvent used for extraction and distillation is N-methylamidomorpholine as the main solvent, the co-solvents are xylene and cumene, and the modifier is cyclidine. The composition is shown in Table 1. The composition of the raw materials is shown in Table. 4. The operating conditions of the extraction distillation column and the solvent recovery column are shown in Table 3, and the results of aromatics separation are shown in Table 5. From the data in Tables 3 and 5, it can be known that under the relatively mild operating conditions of the residual pressure at the top of the solvent recovery tower of 0.04 5 MPa, the top of 72 ° C and the bottom of 186 ° C, a purity of 9 9 · 9% can be obtained. Benzene / toluene mixed aromatics, and the product is neutral. The benzene and toluene products obtained after rectification and separation meet the national excellent standards of GB 3 405-5-9 and GB 3 406-900 respectively. If pure n-formamylmorpholine is used as the extraction distillation solvent, and the same aromatic hydrocarbon purity and yield are achieved, the residual pressure of the recovery tower will be 0.03 8 MPa, and the bottom temperature will be 201. (:, And the content of mixed aromatics will reach 2 ~ 3ppm, which will cause the nitrogen content in toluene products to be significantly higher and more alkaline. It is necessary to use post-treatment measures such as white clay adsorption purification to make the product neutral. (Please (Read the notes on the back before filling out this page)
訂 4 經濟部智慧財產局員工消費合作社印製 本紙張尺度適用中國國家標準（CNS ) A4規格（210X 297公釐） •"14- 1242599 A7 B7 五、發明説明（12 ) 表2 經濟部智慧財產局員工消費合作社印製 原料組成 實施例1 實施例2 實施例5 重量％ 烷烴 C5 - 3.56 0.44 C6 4.45 35.40 3.89 C7 1.94 16.99 3.02 環烷烴 C5 1.51 0.33 - C6 9.20 2.85 8.24 Cv 2.27 0.88 3.34 MCH 0.83 - - 芳烴 C6 79.80 39.83 51.52 C 7 - 0.01 29.5 5 總計 100.00 100.00 100.00 |裝-- (請先閲讀背面之注意事項再填寫本頁) 、\呑 .4 本紙張尺度適用中國國家標準（CNS ) A4規格（210X 297公釐） -16- 1242599 A7 B7 五、發明説明（13) 表3 項目 實施例1 實施例2 實施例5 比較例 理論板數 29 25 38 29 抽 溶劑比 4.5 4.0 5.5 4.5 提 溶劑入塔溫度，°c 90 90 115 90 菡 / ^ > Ν 塔頂回流比 0.3 0.3 0.7 0.3 餾 塔頂操作壓力，MPa 0.1 0.1 0.15 0.1 塔 塔底操作溫度，°C 132 138 175 130 理論板數 16 16 16 16 溶 溶劑入塔溫度，°C 131 136 174 130 劑 塔頂回流比 1.0 1.5 1.5 1.0 回 塔頂操作壓力，MPa 0.045 0.08 0.045 0.045 收 塔頂溫度，t 56 72 72 56 塔 塔底溫度，°C 175 170 186 175 裝— Γ : (請先閲讀背面之注意事項再填寫本頁)Order 4 Printed by the Intellectual Property Bureau of the Ministry of Economic Affairs, Consumer Cooperatives The paper size is applicable to the Chinese National Standard (CNS) A4 specification (210X 297 mm) • " 14- 1242599 A7 B7 V. Description of the invention (12) Table 2 Wisdom of the Ministry of Economic Affairs Composition of raw materials printed by employees of the Property Bureau Cooperative Example 1 Example 2 Example 5 Weight% Alkanes C5-3.56 0.44 C6 4.45 35.40 3.89 C7 1.94 16.99 3.02 Cycloalkanes C5 1.51 0.33-C6 9.20 2.85 8.24 Cv 2.27 0.88 3.34 MCH 0.83- -Aromatics C6 79.80 39.83 51.52 C 7-0.01 29.5 5 Total 100.00 100.00 100.00 | Packing-(Please read the precautions on the back before filling this page), \ 呑 .4 This paper size applies to China National Standard (CNS) A4 specifications (210X 297 mm) -16- 1242599 A7 B7 V. Description of the invention (13) Table 3 Item Example 1 Example 2 Example 5 The number of theoretical plates of the comparative example 29 25 38 29 Pumping solvent ratio 4.5 4.0 5.5 4.5 Column temperature, ° c 90 90 115 90 菡 / ^ > Ν Top reflux ratio 0.3 0.3 0.7 0.3 Distillation column top operating pressure, MPa 0.1 0.1 0.15 0.1 Tower bottom operating temperature , ° C 132 138 175 130 Theoretical plate number 16 16 16 16 Dissolved solvent entering column temperature, ° C 131 136 174 130 Reagent column top reflux ratio 1.0 1.5 1.5 1.0 Back column top operating pressure, MPa 0.045 0.08 0.045 0.045 Closed column top temperature , T 56 72 72 56 Tower bottom temperature, ° C 175 170 186 175 Packing — Γ: (Please read the precautions on the back before filling this page)
、1T 經濟部智慈財產局員工消費合作社印製 本紙張尺度適用中國國家標準（CNS ) Α4規格（210X297公釐） -17- 1242599 A7 B7 五、發明説明（Μ) 表4 項目 實施例1 實施例2 實施例3 實施例4 比較例 苯產品 純度，重量％ 99.97 99.99 99.97 99.97 99.97 非芳，ppm 300 100 290 300 300 硫，ppm 0.2 0.2 0.5 0.3 1 糸吉_黑占，C 5.49 5.50 5.49 5.49 5.49 中性試驗 中性 中性 弱酸性 中性 弱酸性 收率，重量％ 99.86 99.60 99.87 99.88 99.66 非芳煙產品 芳烴，重量％ 0.54 0.32 0.51 0.47 1.33 溶劑，ppm <1 <1 <1 <1 <1 裝-- '- (請先閱讀背面之注意事項再填寫本頁) 訂 經濟部智慧財產局员工消費合作社印製 本紙張尺度適用中國國家標準（CNS ) A4規格（2】0X 297公釐） -18- 1242599 A7 B7 五、發明説明（15) 表5 項目 實施例5 苯產品 純度，重量％ 99.90 非芳，ppm 1000 氮，ppm <0.5 中性試驗 中性 收率，重量％ 99.6 非芳烴產品 芳烴，重量％ 0.65 溶劑，：ppm <1 ;裝-- (請先閱讀背面之注意事項再填寫本頁) -口 經濟部智慧財產局貞工消费合作社印製 圖示符號說明 1. 管線 2. 管線 3. 換熱器 4. 抽提蒸餾塔 5. 管線 6 · 冷凝器 7. 回流罐 8. 管線 9. 管線 10. 再沸器 11. 管線 .4 本纸張尺度適用中國國家標準（CNS ) A4規格（210X 297公釐） -19- 1242599 A7 B7 五、發明説明（16) 12.溶劑回收塔 1 3.管線 14.冷凝器 1 5 .真空系統 1 6.凝液罐 1 7.管線 1 8.管線 19. 再沸器 20. 管線 ^#¾衣-- 'L (請先閱讀背面之注意事項再填寫本頁) 訂 .4 經濟部智慧財產局員工消費合作社印製 本纸張尺度適用中國國家標準（CNS ) A4規格（210 X 297公釐） -20-、 1T Printed by the Consumers ’Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs. The paper size is applicable to the Chinese National Standard (CNS) A4 specification (210X297 mm) -17-1242599 A7 B7 V. Description of invention (M) Table 4 Project Example 1 Implementation Example 2 Example 3 Example 4 Comparative Example Benzene Product Purity, wt% 99.97 99.99 99.97 99.97 99.97 Non-aromatic, ppm 300 100 290 300 300 Sulfur, ppm 0.2 0.2 0.5 0.3 1 Koji_Heizhan, C 5.49 5.50 5.49 5.49 5.49 Neutral test neutral neutral weak acid neutral weak acid yield, wt% 99.86 99.60 99.87 99.88 99.66 aromatics, non-aromatic tobacco products, wt% 0.54 0.32 0.51 0.47 1.33 solvent, ppm < 1 < 1 < 1 < 1 < 1 Pack-'-(Please read the notes on the back before filling out this page) Order printed by the Intellectual Property Bureau of the Ministry of Economic Affairs, Consumer Cooperatives This paper is printed in accordance with China National Standard (CNS) A4 specifications (2) 0X 297 (Mm) -18- 1242599 A7 B7 V. Description of the invention (15) Table 5 Project Example 5 Purity of benzene product, weight% 99.90 non-aromatic, ppm 1000 nitrogen, ppm < 0.5 neutral test neutral yield , Wt% 99.6 Non-aromatic products aromatics, wt% 0.65 Solvent, ppm <1; Packing-(Please read the precautions on the back before filling out this page)-Printed by Zhengong Consumer Cooperative, Intellectual Property Bureau, Ministry of Economic Affairs Explanation of symbols 1. Pipeline 2. Pipeline 3. Heat exchanger 4. Extractive distillation column 5. Pipeline 6 · Condenser 7. Return tank 8. Pipeline 9. Pipeline 10. Reboiler 11. Pipeline. 4 This paper Standards are applicable to China National Standard (CNS) A4 specifications (210X 297 mm) -19- 1242599 A7 B7 V. Description of invention (16) 12. Solvent recovery tower 1 3. Pipeline 14. Condenser 1 5. Vacuum system 1 6. Condensate tank 1 7. Pipeline 1 8. Pipeline 19. Reboiler 20. Pipeline ^ # ¾ 衣-'L (Please read the precautions on the back before filling this page) Order. 4 Consumption by Employees of Intellectual Property Bureau, Ministry of Economic Affairs The paper size printed by the cooperative is applicable to the Chinese National Standard (CNS) A4 (210 X 297 mm) -20-