petroleun is amixture of thousands of different compounds.most of them are hydrocarbons,compounds of carbon and hydrogen which differ from each other only in the number of carbon and hydrogen atoms in their molecules.the molecules are of different sizes and have different boiling points,use is made of this in separating them.
it is not profitable,or necessary,to separate out all the individual hydrocarbons in crude oil.it is separated into a few fractions which boil over different range of temperature.each of the fractions is still a mixture of many different compounds.
the industrial process is carried out on a huge scale in an fractionating column.the hot mixture of liquid and vapor is led into the column.the liquid drops down to the bottom of the tower where it is tapped off.the vapor rises up the tower where it meets a series of trays containing bubble caps.
A tary may consist of hundreds of bubble caps.As vapor passes up through the bubble cap,it is forced to pass through liquid in the tray before it can go further up the tower.the liquid in the tray has formed by condensation of previous suoolies of vapor.As the vapor passes through the bubble cap it cools and the compounds in the vapor with the highest bpiling the tower to the next tray.This process continues up through to the tower.huydrocarbons with highest boiling points condense in the lower trays;this ia the fraction called gas oil.Those with medium boiling points condense in the upper trays;this is the fraction called kerosene.Those with lower boiling points still do not condense,and aer led off from the top of the tower as vapor;this is the fraction called gasoline,or naphtha.

petroleum is a mixture of thousands of different compounds.most of them are hydrocarbons,compounds of carbon and hydrogen which differ from each other only in the number of carbon and hydrogen atoms in their molecules.the molecules are of different sizes and have different boiling points,use is made of this in separating them.
石油是由数千种不同成分组成的混合物。其中大部分是碳氢化合物，即分子中仅仅是因为碳原子和氢原子数量不同而导致碳氢不同的混合物。这些分子有不同的大小和沸点，【利用这些特点可以对它们进行分离】。

it is not profitable,or necessary,to separate out all the individual hydrocarbons in crude oil.it is separated into a few fractions which boil over different range of temperature.each of the fractions is still a mixture of many different compounds.
从原油中分离这些单个的碳氢化合物不是有利或者必须的。它们被分解为在不同温度范围内沸腾的若干部分，每一部分仍然是许多不同化合物组成的混合物。

the industrial process is carried out on a huge scale in an fractionating column.the hot mixture of liquid and vapor is led into the column.the liquid drops down to the bottom of the tower where it is tapped off.the vapor rises up the tower where it meets a series of trays containing bubble caps.
化工处理过程是在一个大型的圆柱形分馏器中进行的。液态和气态的高温混合物送入分馏器中，液态物质从分馏塔的底部滴下并由管道排出。气态物质在分馏塔中逐步上升到顶部，在那里它会遇到一系列包含圆形盖子的【托盘】。

A tary may consist of hundreds of bubble caps.As vapor passes up through the bubble cap,it is forced to pass through liquid in the tray before it can go further up the tower.the liquid in the tray has formed by condensation of previous suoolies of vapor.As the vapor passes through the bubble cap it cools and the compounds in the vapor with the highest bpiling the tower to the next tray.This process continues up through to the tower.hydrocarbons with highest boiling points condense in the lower trays;this ia the fraction called gas oil.Those with medium boiling points condense in the upper trays;this is the fraction called kerosene.Those with lower boiling points still do not condense,and aer led off from the top of the tower as vapor;this is the fraction called gasoline,or naphtha.
每一个托盘是由几百个圆形的盖子组成。当气态物质上升通过圆形盖子的时候，气态物质在进一步上升到分馏塔的上部之前会强迫通过托盘中的液体物质，这些液体物质就会使得先前进入的气态物质冷凝。当气态物质通过使其冷却的圆形盖子，其中沸点较高的成分就进入分馏塔中下一个托盘。这个过程已知持续到分馏塔的顶部。沸点最高的碳氢化合物在底部的托盘中冷凝，这一部分就是煤气；那些具有中等沸点的物质在较高层的托盘中冷凝，这一部分得到的是煤油；沸点较低仍然没有冷凝的物质在分馏塔的顶部以气体的形式分出，这就是汽油，也称为挥发油。