【正文】
表 222 浮閥塔工藝設(shè)計(jì)計(jì)算總表 數(shù)值及說(shuō)明 備 注 精餾段 提餾段 塔徑 D,m 塔高 H,m 塔板型式 塔板數(shù)(層) 空塔氣數(shù) u,m/s 堰長(zhǎng) l,m 堰高 h,m 降液管底隙高度 ho,m 浮閥數(shù) N,個(gè) 閥孔氣速 u,m/s 閥孔動(dòng)能因數(shù) Fu 臨界閥孔氣速 m/s 孔 心距 t,m 排間距 t’ m 單板壓降 Pa 液體在降液管內(nèi)清液層高度 H,m 液體在降液管內(nèi)停留時(shí)間θ ,s 泛點(diǎn)率% 氣相負(fù)荷上限( VS) max,m3/s 氣相負(fù)荷下限( VS) min,m3/s [年產(chǎn)十萬(wàn)噸二甲醚裝置分離精餾工段的工藝設(shè)計(jì) ] 30 Annual output of 10,000 tons of dimethyl ether distillation Section in the design of sepration device INTRODUCTION Motor Vehicle population is increasing in China,and the country is faced with a serious energy supply problem. China’s smaller reserves of petroleum and risingdemand for petroleum products result in a import postion which is not likely to be reversed. Therefore,strong effeorts should be made to find mercially viable alternatives to imported oil and oil products for automobiles to satisfy the shortand mediumterm needs of the country. DME is one of the promising fuel substitutes for petroleum diesel fuel which can be used by pression ignition engines because it is a clean fuel with good selfignition characteristics and almost smokefree bustion. Numerous investigation of DMEfulled engines have indicated that DME offers an excellent promise as an alternative fuel for pressionignition operation in the automotive sector with its ultralow emissions. The use of dimethyl ether(DME)as an alternative fuel appears to be a promising approach for simultaneously minimizing NOx and soot emission from conventional diesel engines. The low selfignition temperature of 508K and the high oxygen content Of percent(mass fraction) are two major factors characterizing low soot and unburned total hydrocarbon(THC)emission Preparation of dimethyl ether mainly methanol dchydration and Onestep syhesis. With the tradional methanol syhesis pared to syhesis of dimethyl ether,onestep syhesis of dimethyl ether process more rational economy, more petive in the market and it is moving towards industrialiazation. Curently , syhesis gas to dimethyl ether is the latest technology preparation of dimethyl ether. Compared with methanol dchydration , system of direct synthesis of DME as the existence of unreacted synthesis gas and carbon dioxide it want to get high purity dimethyl ether, more plicated separation process. Developed mainly in the separation process such as chemical absorption and distillation unit operation in the process of dimethylethyl ether with higher purity design aimed at separating the distillation process for process design. Separation of DME , methanol and water ternary system. Design of distillation towers used valve. Use the whole top of the tower condenser cooling device used to provide sufficient by calculating the number of theoretical plate design and calculation of process dimensions derived column diametet, the effective tower, sieve number. Checking through the sieve of fluid mechanics, to prove that the indicator data are in line with standards to ensure the smooth progress of distillation process and to improve efficiency as much as possible. 。 ) ( 3) 塔板布置及浮閥數(shù)目排列 : [年產(chǎn)十萬(wàn)噸二甲醚裝置分離精餾工段的工藝設(shè)計(jì) ] 29 浮閥排列方式采用等腰三角形叉排。 ③ 出口堰高: owLw hhh ?? ????? owLw hhh ④ 降液管的底隙高度 oh 液體通過(guò)降液管底隙的流速一般為 ~,取液體通過(guò)降液管底隙的流速m/??ou ,則有: m125 59.. 009 14 ????? ow so ul Lh ( oh 不宜小于 ~,本結(jié)果滿足要求) ⑤ 降液管的寬度 dW 和降液管的面積 fA 由 ?Dlw ,查化原下 P147圖 1116 得 ,?? Tfd AADW ,即: ?dW , 22 m5 3 8 8 ?? DA T , ?fA 。 (1) 溢流裝置 ① 堰長(zhǎng) lW 取堰長(zhǎng) lW=,即 lW= =( m) ② 堰上液層高度 hOW [年產(chǎn)十萬(wàn)噸二甲醚裝置分離精餾工段的工藝設(shè)計(jì) ] 28 ? ? 1 1 9 9 0 7 8 ????owh 符合要求。 m a x ?? uu 塔徑: 2 9 39。m a x smCu VVL ????? ??? 取安全系數(shù)為 ,則 m /39。39。/39。39。20 ?C 。39。?TH 及板上 液層高度 39。39。39。=(m3/s) Lh’=(m3/h) (二 )塔徑的計(jì)算 ( 2) 精餾段計(jì)算: 03 97 91 ?????????????????????????????? VLssVL ?? 初選塔板間距 mm350?TH 及板上液層高度 mm70?Lh ,則: ???? LT hH [年產(chǎn)十萬(wàn)噸二甲醚裝置分離精餾工段的工藝設(shè)計(jì) ] 27 根據(jù)以上數(shù)據(jù),查史密斯關(guān)聯(lián)圖 ?C 。以重關(guān)鍵組分為基準(zhǔn)物,即 α BB = 1。 ( 2)安托萬(wàn)公式 Ln Pis = A – B/(T+C) (Pis :mmHg, T: K) 查《石油化工基礎(chǔ)數(shù)據(jù)手冊(cè)》 表 26 安托萬(wàn)公式數(shù)據(jù)表 ( 3)采用試差法計(jì)算 壓力不太高時(shí)按完全理想息計(jì)算, Ki=ln Pis/p T 給定 P Y 設(shè)定 T Ki=ln Pis/p ∑ KiXi 1≤ ε 結(jié)束 調(diào)整 T N yi 圖 22 試差法結(jié)構(gòu)圖 [年產(chǎn)十萬(wàn)噸二甲醚裝置分離精餾工段的工藝設(shè)計(jì) ] 18 試差過(guò)程見(jiàn)表 27 表 27 進(jìn)料 溫度試差過(guò)程 結(jié)果在 ,即 ℃ 時(shí), ∑ KiXi≈ 1,故進(jìn)料溫度為