NKCJS-1（废塑料再生利用）技术

NKCJS-1 (Waste Plastic Recycling) Technology

随着塑料工业的发展和消费水平的提高，塑料制品的应用从工农业生产到衣食住行无处不在，塑料垃圾也随之大量的向我们袭来。它们不腐烂、不分解，已经成为十分注目的社会问题。

废塑料主要来源为食品包装，饮料瓶，容器及各种薄膜等制品，是可回收利用的主要部分。

目前各国的废塑料的处理比例都不高，大部分塑料废品混合在垃圾中，对环境造成极大危害。

在国外对聚乙烯（PE）和聚丙烯（PP）的废弃物，很容易分离出较纯品，主要以机械再生为主，工艺为：表面除杂 → 粉碎 → 洗涤 → 干燥 → 造粒 → 包装

中国对PE和PP回收利用方式主要有两种，一是对于加工中的边角料破碎造粒后按15~25％掺入新料中再模塑料制品，另一是对于较清洁且老化不十分严重的则经破碎和清洗后造粒降格使用。

对于不清洁，严重老化或PE、PP混在一起的废塑料，化学再生则成为一个主渠道，即通过热解转化为化工原料或燃油，毋需二次回收，是各国公认有效再生优生途径。

混合废塑料在无氧条件下，热解有直接热解和催化热解两种方法，一是直接热解所需温度高（400~500℃），残渣量相对多，气体含量大；

二是催化裂解，采用二段式装置，裂解温度为300~400℃，可以调节反应条件和催化剂以得更多的要求产品，目前使用的的催化剂有Y型沸石（NKF-7）及ZSM-5沸石（NKF-5）等。

With the development of the plastic industry and the improvement of consumption level, the application of plastic products from industrial and agricultural production to food, clothing, housing and transportation is everywhere, and plastic waste is also coming to us in large quantities. They do not decay, do not decompose, and have become a very interesting social problem.

The main source of waste plastics is food packaging, beverage bottles, containers, and various films, which are the main part of recycling.

At present, the proportion of waste plastics in various countries is not high, and most of the plastic waste is mixed in garbage, which causes great harm to the environment.

In foreign countries, the waste of polyethylene (PE) and polypropylene (PP), it is easy to separate out the purer products, mainly based on mechanical regeneration, the process is:

surface impurity removal → crushing → washing → drying → granulation → packaging

There are two main ways of recycling PE and PP in China, one is that the scrap material in the processing is crushed and granulated according to 15 to 25% of the new material and then molded plastic products, and the other is that for the cleaner and less serious aging, it is used after crushing and cleaning granulation.

For waste plastics that are not clean, severely aged or mixed with PE and PP, chemical recycling has become a main channel, that is, it is converted into chemical raw materials or fuel oil through pyrolysis, without the need for secondary recycling, which is recognized by all countries as an effective regenerative eugenic way.

Under the condition of no oxygen, pyrolysis of mixed waste plastics has two methods: direct pyrolysis and catalytic pyrolysis, one is that the temperature required for direct pyrolysis is high (400~ 500 °C), the amount of residue is relatively large, and the gas content is large.

The second is catalytic cracking, using a two-stage device, cracking temperature of 300 ~ 400 °C, can adjust the reaction conditions and catalyst to obtain more required products, the catalyst currently used are Y-type zeolite (NKF-7) and ZSM-5 zeolite (NKF-5) and so on.