问题 问答题 简答题

影响甲醇合成水冷器水冷效果的主要原因有哪些?

答案

参考答案:

水冷效果下降可能有以下几个原因:

1)水量明显减少,其冷却效果受到影响。可以采取开大冷却水进口阀、提高冷却水压来达到增加冷却水量的目的。

2)水冷器水层管壁积垢和淤泥加剧,这将影响热量的传递和热量的移走,

使水冷效果受到影响。

3)水质处理比较差,水中可能夹带塑料纸等杂物,这种夹带物对水冷器的

冷却效果有很大影响,尤其对列管换热器,这些杂物会聚积在冷却器进口的花板上,堵塞孔径,导致流水不畅通,影响水冷效果,如果发生这种情况,除了加强水处理净化工作外,还可以在水冷器进水前安装两只并联的过滤器,以清除杂物。

4)甲醇合成时会产生石蜡,生成的石蜡会吸附在冷凝器管壁内,随着时间的延长,影响增大。如果结蜡严重,影响生产,可以采取停车用蒸汽吹扫、热煮方法去除。

单项选择题
填空题

[A] A machine has been developed that pulps paper and then processes it into packaging, e.g. egg-boxes and cartons. This could be easily adapted for local authorities use. It would mean that people would have to separate their refuse into paper and non-paper, with a different dustbin for each. Paper is, in fact, probably the material that can be most easily recycled; and now, with massive increases in paper prices, the time has come at which collection by local authorities could be profitable.

[B] Recycling of this kind is already happening with milk bottles, which are returned to the dairies, washed out, and refilled. But both glass and paper are being threatened by the growing use of plastic. More and more dairies are experimenting with plastic bottles, and it has been estimated that if all the milk bottles necessary were made of plastic, then British dairies would be producing the equivalent of enough plastic tubing to encircle the earth every five or six days!

[C] The package itself is of no interest to the shopper, who usually throws it away immediately. Useless wrapping accounts for much of the refuse put out by the average London household each week. So why is it done Some of it, like the cellophane on meat, is necessary, but most of the rest is simply competitive selling. This is absurd. Packaging is using up scarce energy and resources and messing up the environment.

[D] The trouble with plastic is that it does not rot. Some environmentalists argue that the only solution to the problem of ever growing mounds of plastic containers is to do away with plastic altogether in the shops, a suggestion unacceptable to many manufacturers who say there is no alternative to their handy plastic packs.

[E] Little research, however, is being carried out on the costs of alternative types of packaging. Just how possible is it, for instance, for local authorities to salvage paper, pulp it and recycle it as egg-boxes Would it be cheaper to plant another forest Paper is the material most used for packaging--20 million paper bags are apparently used in Great Britain each day--but very little is salvaged.

[F] It is evident that more research is needed into the recovery and re use of various materials and into the cost of collecting and recycling containers as opposed to producing new ones. Unnecessary packaging, intended to be used just once, and making things look better so that more people will buy them, is clearly becoming increasingly absurd. But it is not so much a question of doing away with packaging as using it sensibly. What is needed now is a more sophisticated approach to using scarce resources for what is, after all, a relatively unimportant function.

[G] To get a chocolate out of a box requires a considerable amount of unpacking: the box has to be taken out of the paper bag in which it arrived; the cellophane wrapper has to be torn off, the lid opened and the paper removed; the chocolate itself then has to be unwrapped from its own piece of paper. But this insane amount of wrapping is not confined to luxuries. It is now becoming increasingly difficult to buy anything that is not done up in cellophane, polythene or paper.

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