Energy-efficient Petrochemical Polimerization PP powder pelletizing line

Description of Process Characteristics

There are a large number of batch liquid phase bulk polymerization polypropylene production lines in China, referred to as small bulk polypropylene. The scale of production is small, and the production capacity ranges from several thousand tons to tens of thousands of tons. Because of its simple process, low investment in equipment, and quick results, it has developed rapidly.

However, the batch process polypropylene also has the following disadvantages: the production is powder molding, which is limited in the application range, and the antioxidant-free, powder is easily aged during storage. The performance of the product is unstable, and the performance indexes fluctuate greatly. At the same time, the ash content, volatiles and chlorine content are too large. Therefore, small bulk polypropylene is mainly used in low-end products, while the range of products is narrow, mostly is spinning, woven bags, packing belts, and small injection molding products.

Therefore, the above small bulk polypropylene powder needs to be modified and granulated to enhance its various qualities, and can be applied to middle and high-end products and some special materials. The main enhancements are as follows:

1. Before the granulation, the polypropylene powder is not homogenized by stirring, and the anti-oxidant, halogen absorbent and lubricant are added in the process of  the granulation to make general-purpose granules, which improves the comprehensive quality, stability and application range of the polypropylene.

2. The granulation line is equipped with a vacuum degassing unit and a melt filter to effectively reduce its volatiles and ash.

3. Add special-purpose additives (such as nucleating agents, UV absorbers, slip agents, etc.) to make special materials to increase the added value of the products.

   On the other hand, there is a huge demand for the special materials of homogenized polypropylene, copolymerized polypropylene and polyethylene in China, such as casting film PP, HDPE gas pipeline and low VOC resin etc. Petrochemical enterprises can meet part of the demand by modifying granulations on the basis of general brands.

Efficient-energy GWHS Reciprocating compounding pelletizing line:

Cenmen company has developed high efficiency and energy saving GWHS Reciprocating compounding pelletizing line, which is very suitable for petrochemical and coal chemical polymerization PP, HDPE powder modification processing special materials, single machine output 3-5 tons / hour, 3-5 sets combined unit can plan a special material project with an annual output of 100,000 tons.

GWHS Reciprocating kneader characteristics:

The reciprocating kneader is with special compounding principle, flexible low shearing mixing as well as high efficient dispersion effect. It not only has conventional radial shearing mixing, but also has axial stretch mixing, shearing, plastifying, compounding, dispersing and streatching to the polymer melt in the kneader.

1. Good mixing and dispersing effect: the screw elements adopts a 4-flight design, complex composite movement between intermittent screw elements and barrel pins, and the material in the groove is subjected to instantaneous high-frequency shearing, stretching and splitting and shunting effects, thereby having a very excellent dispersion mixing and distribution mixing effect, the mixing effect is more than 20 times that of the twin-screw extruder.

2. Low energy consumption: The above mentioned special flexible compounding principle makes it have excellent mixing and dispersing effect, and has a lower energy consumption ratio, energy consumption ratio is 0.15-0.17kw.h/kg, reduce energy consumption by more than 20% compared to twin-screw extruders.

3. Flexible mixing and low temperature rise: The above mentioned special flexible compounding principle effectively reduces the heat of shearing to cause the melt temperature rising too high. Thereby, volatilization and decomposition of the resin and the organic additives in the melt are prevented.

4. High working volume and high output: the screw and barrel of the reciprocating kneader give a higher working volume, and the intermittent screw interacts with the pins to make it have a good self-cleaning effect.

5. Compared with twin screw extruder equipment, it can save space, and directly reduce the using area of the plant, and also greatly reduce the engineering infrastructure costs such as electricity.

Process flow of the production line

 The GWHS-160/160 reciprocating extruder main unit in assembly: