An Introduction to Distillation 蒸餾概述
1. Petroleum refining is the separation of petroleum into fractions and the subsequent treating of these fractions to make them into petroleum products. Most petroleum products,including kerosenes,fuel oils,lubricating oils,and waxes,are fractions of petroleum that have been treated to remove undesirable components. Other products,for example,gasolines,aromatic solvents,and even some asphalts,are totally or partly synthetic in that they have compositions that are impossible to achieve by direct separation of these materials from crude petroleum. They result from chemical processes that change the molecular nature of selected portions of crude petroleum; in other words,they are the products of refining or they are refined products.
1、石油煉制即將石油分離成各種餾分，然后將這些餾分經(jīng)過處理，制成各種石油產(chǎn)品。大部分石油產(chǎn)品，包括煤油、燃料油、潤滑油和石蠟，都是原油經(jīng)過處理去掉不需要的成分而得到的石油餾分。其他石油產(chǎn)品，如汽油、芳烴溶劑、甚至包括有些瀝青，則是通過完全或者部分合成而制造的。因為組成這些產(chǎn)品的物質(zhì)成分無法通過直接分離原油獲得，而是通過化學(xué)反應(yīng)過程，從原油中選定某些成分并改變其分子屬性而獲得的。換言之，它們是通過煉制得到的，或稱為煉制產(chǎn)品。
2. Refining petroleum is a complex series of steps by which the original crude material is eventually converted into salable products with the desired qualities and,perhaps more important,in the amounts dictated by the market.
2、石油煉制包含一系列復(fù)雜的過程。通過這些過程，石油原料最終轉(zhuǎn)化成為可銷售的產(chǎn)品。這些產(chǎn)品在質(zhì)量上符合人類需要，而更重要的是它們在數(shù)量上符合市場要求。
3. In fact,a refinery is essentially a group of manufacturing plants that vary in number with the variety of products produced; refinery processes must be selected and products manufactured to give a balanced operation: that is,crude oil must be converted into products according to the rate of sale of each. For example,the manufacture of products from the lower boiling portion of petroleum automatically produces a certain amount of higher boiling components. If the latter cannot be sold as,say,heavy fuel oil,they accumulate until refinery storage facilities are full. To prevent the occurrence of such a situation,the refinery must be flexible and able to change operations as needed. This usually means more processes-a cracking process to change an excess of heavy fuel oil into more gasoline with coke as the residual product or a vacuum distillation process to separate the heavy oil into lubricating oil stocks and asphalt-to accommodate the ever-changing demands of the market.
3、實際上，煉油廠從根本上說是一組生產(chǎn)裝置，其數(shù)量根據(jù)生產(chǎn)產(chǎn)品的不同而不同。煉油工藝須經(jīng)選擇，產(chǎn)品生產(chǎn)應(yīng)該平衡：即從原油生產(chǎn)產(chǎn)品必須依據(jù)每一產(chǎn)品的銷售速度而進(jìn)行。比如，從沸點較低的組分生產(chǎn)石油產(chǎn)品，就會自動產(chǎn)生一定數(shù)量的高沸點產(chǎn)品。如果高沸點產(chǎn)品，如重燃料油，無法銷售，這些產(chǎn)品就會積壓，直到裝滿煉廠的儲存設(shè)施。要避免這種情況出現(xiàn)，煉廠應(yīng)采取靈活措施，并能夠根據(jù)需要改變操作。一般而言，這意味著需要更多的工藝以適應(yīng)不斷變化的市場需求：運用裂化工藝將過剩重燃料油轉(zhuǎn)化成汽油，而焦碳成為殘余品；或者運用真空蒸餾工藝將重油分解成潤滑油和瀝青。