化工專業(yè)英語(2)

1、第四課第四課Unit Operations and FlowsheetsMain PointlThe concept of unit operation and the drawings of some units in flowsheets. New words and expressionsunit operationreactorheat exchangerpump mixerseparatordryer單元操作單元操作反應(yīng)器反應(yīng)器熱交換器熱交換器泵泵混合器混合器分離器分離器干燥器干燥器New words and expressionsfilterabsorberadsorbercent

2、rifuge distillationcondensationfiltering過濾器過濾器吸收器吸收器吸附器吸附器離心分離器離心分離器蒸餾蒸餾濃縮濃縮過濾過濾New words and expressionspropellershaftcentrifugal pumpcompressor expanderturbinesplitter螺旋葉片螺旋葉片軸軸離心泵離心泵壓縮機(jī)壓縮機(jī)膨脹器膨脹器渦輪渦輪分裂機(jī)分裂機(jī)New words and expressionscombinerinterconnect venerablefledglingincarnations組合器組合器互相連接互相連接古老的

3、古老的無經(jīng)驗(yàn)的人無經(jīng)驗(yàn)的人化身化身New words and expressionsgeneric thin layer chromatographyliquid chromatographyvapour chromatography electron spin resonancefree radicalX-ray spectroscopy普通的普通的薄層色譜薄層色譜液相色譜液相色譜氣相色譜氣相色譜電子自旋共振電子自旋共振(順磁順磁)自由基自由基X射線光譜射線光譜Text Unit Operations and Flowsheets Every chemical process is a co

4、llection of units interconnected by streams. 任何化學(xué)工藝都是由流動(dòng)相互連接的單元的集合。Text This is the concept of unit operations, the first, and most venerable, paradigm adopted by the fledgling discipline of chemical engineering near the beginning of the twentieth century. 這就是單元操作的概念，是二十世紀(jì)初期新興的化學(xué)工程學(xué)科所采用的最基礎(chǔ)和古老的概念。Te

5、xt The five most common units are reactors, heat exchangers, pumps, mixers, and separators. 五個(gè)最常見的單元是反應(yīng)器，熱交換器，泵，混合器和分離器。Text The design and operation of these five units, which exist in hundreds of incarnations, are the focus of the traditional chemical engineering curriculum. 這五種單元，其存在有數(shù)百種形式，其設(shè)計(jì)和操作

6、是傳統(tǒng)化學(xué)工程學(xué)科的中心。Text Furthermore, most chemical engineering curricula have a senior-level laboratory course entitled unit operations. 此外，大部分化學(xué)工程課程都有稱為單元操作的高級(jí)實(shí)驗(yàn)課。Text As we saw in the ammonia process, the reactor is usually the key unit. The reactor will often dictate whether a chemical process is possi

7、ble. 正如我們?cè)诤铣砂惫I(yè)中所見，反應(yīng)器通常是關(guān)鍵的單元。反應(yīng)器常常決定一個(gè)化學(xué)過程的可能性。Text Separators are secondary only to the reactor in most processes; the performance of the separator(s) will often determine if a process is profitable. 在大部分工藝中分離器僅次于反應(yīng)器；分離器的性能通常決定了一個(gè)工藝是否能夠盈利。Text Examples of separators include dryers, filters, absor

8、bers, adsorbers, and centrifuges. 分離器的例子有干燥器，過濾器，吸收器，吸附器和離心分離器。Text The method used to separate a mixture distillation, condensation, or filtering - is usually indicated by a specific symbol on the flowsheet. We will introduce these specific units later, as needed. 用于分離混合物的方法如蒸餾，濃縮或過濾通常在流程圖用特殊的符號(hào)指明。

9、根據(jù)需要，我們將在隨后介紹這些特殊單元。Text Additional units could be added to the ammonia process. Reactants should be mixed before entering a reactor, not just combined. 合成氨工藝中還需要其他的單元，反應(yīng)物在進(jìn)入反應(yīng)器之前需要混合而不是僅僅加到一起。Text Simply combining flour, eggs, water, and baking soda is not enough. The reactants must be mixed to bak

10、e a cake. 把面粉，雞蛋，水和烘焙蘇打簡(jiǎn)單的放到一起是不夠的。這些物質(zhì)需要混合后來烘焙蛋糕。Text The simplest mixer combines two or more streams into one stream: A propeller at the end of a shaft must be added to indicate mixing: 最簡(jiǎn)單的混合器把兩個(gè)或更多的流動(dòng)變成一股： 軸的末端必須加上螺旋槳以表示混合：Text Mixers are important for solids and liquids. Gases, such as N2 and H

11、2, tend to mix on their own. 混合器對(duì)于固體和液體是很重要的。氣體如氮?dú)夂脱鯕饪梢宰詣?dòng)混合。Text We neglected to add pumps to the ammonia process. Fluids are usually moved about a process by pumps. 我們?cè)诤铣砂惫に囍泻雎粤怂械谋?。流體通常由泵驅(qū)動(dòng)在工藝中流動(dòng)。Text A pump increases a fluids pressure and the fluid flows from high pressure to lower pressure. 泵增加了

12、流體的壓力，且流體是從高壓到低壓流動(dòng)。Text Or, fluid pressure might be increased to condense the fluid (from a gas to a liquid) or speed a chemical reaction. A generic pump may be represented as 或者，流體壓力必須增加以壓縮流體(從氣體到液體)，或加快反應(yīng)速度。一般的泵可以表示為Text Because liquids and gases respond differently to an increase in pressure (a g

13、as is compressed whereas a liquid is not) different units are used to distinguish this difference. 因?yàn)橐后w和氣體對(duì)于增大壓力有不同的表現(xiàn)(氣體能夠被壓縮而液體不能)，所以需要用不同的單元來區(qū)分。Text A centrifugal pump for liquids may be represented as Whereas a centrifugal gas compressor may be represented as or simply 對(duì)于液體的離心泵可以表示為 而氣體離心壓縮器表示為

14、或簡(jiǎn)單為Text A gas expander, or turbine, is similar to the gas compressor above, but with the flows reversed. 氣體膨脹器或渦輪與上述氣體壓縮器類似，只是流動(dòng)方向相反。Text We need some valves to control the flows. The simplest representation of a valve is 我們需要一些閥門來控制流動(dòng)。閥門最簡(jiǎn)單的表示為Text Finally, we offer two stylistic conventions for f

15、lowsheest. Avoid crossing streams. If streams must cross, indicate explicitly whether the streams mix or dont mix. 最后，我們說明兩種流程圖中所用的格式慣例。如果兩股流動(dòng)交叉，應(yīng)當(dāng)指明其是否混合。Text A flowsheet with two streams as shown below on the left is ambiguous. Do the contents of the streams mix? 流程圖中像下圖左所表示的兩股流動(dòng)是模糊不清的。它們是否混合？Text

16、 If the contents of the streams combine (and split), indicate this explicitly with a splitter or combiner, as shown in the middle diagram below. 如果它們結(jié)合(且分開)，應(yīng)當(dāng)明確的用分離器或結(jié)合器表示，如下圖中所示。Text If the streams cross without mixing, this should be indicated as shown on the right below. The primary stream should be unbroken when streams cross. 如果它們僅僅是交叉而沒有混合，可表示為下圖右所示。當(dāng)它們交叉時(shí)，主要的一股流動(dòng)不能被斷開。Text Only horizontal and vertical li