问题 问答题 简答题

什么是重整指数?什么是芳烃潜含量?

答案

参考答案:

重整指数和芳烃潜含量都是描述重整原料油质量的具体指标。我国一般用芳烃潜含量,国外常用重整指数。

重整指数通常用(N+2A)表示,N表示环烷含量,A表示芳烃含量,它的具体定义是:

(N2A)CiN%2CiA%

式中CiN—原料中环烷烃的百分含量;

Ci—原料中芳烃的百分数。

显然原料中环烷和芳烃的含量愈高,重整生成油中的芳烃产量愈大,辛烷值愈高,这就A是重整指数的基本涵义。

芳烃潜含量(Ar%)的涵义与重整指数(N+2A)的涵义相近,其计算方法是:

Ar%aC6N%bC7N%cC8N%2A)Aro%

式中,Ar%为原料中总的芳烃含量;a、b、c分别为C6N、C7N、C8N与相应生成的苯(B)、甲苯(T)、二甲苯(X)之间的转换系数,其值分别为:o

aMB/MC6N78/840.93

bMT/MC7N92/930.94

cMX/MC8N102/1120.95

NN式中,MB、MT、MX分别为B、T、X的摩尔质量,MC6、MC7、MC8N分别为C6

环烷烃、C7环烷烃和C8环烷烃的摩尔质量。

芳潜=0.93*C6环烷+0.94*C7环烷+0.95*C8环烷+0.95*C9环烷+0.96*C10环烷+芳烃

填空题


The central problem of economics is to satisfy the people’s and nation’s wants. The problem we are faced with is that our (1) , here identified as money, are (2) . The only way we can resolve our (3) is to make choices. After looking at our resources, we must examine our list of (4) and identify the things we need (5) , those we can postpone, and (6) we cannot afford. As individuals, we face the central problem involved in economics — deciding just how to allocate our limited resources to provide ourselves with the greatest (7) of our wants.
Nations face the same problem. As a country’s population (8) , the need for more goods and services grows (9) . Resources necessary to production may increase, but there are (10) enough resources to satisfy the total desires of a (11) . Whether the budget meeting is taking place in the family living-room, in the conference room of the corporation (12) of directors, or in the chamber of the House of Representatives in Washington, the basic problem still exists. We need to find (13) of allocating limited resources in order to satisfy unlimited wants.
A short time ago, economists divided goods into two categories, free and economic. The former, like air and water, were in (14) abundance that economists had no concern about (15) of scarcity and what to do about it. Today many of these "free goods" are in (16) very expensive to use. Pollution has made clean air and water expensive for producers who have to filter their waste products, for consumers who ultimately pay for the producers’ extra costs, and (17) tax-payers who pay for the government’s involvement in cleaning the environment.
In the 1990s, almost all goods are (18) . Only by effort and money can they be (19) in the form people wish.
Meeting the needs of people and the demands from resources available leads to the basic activity of production. In trying to (20) unlimited wants from limited economic goods, production leads to new problems in economics.

单项选择题 A1/A2型题