Nanjing KY Chemical Machinery Co., Ltd.

PT Plastic Interview

PT: Production energy consumption, production efficiency and product quality are closely related to the production cost of blending granulation. First of all, what are the main factors affecting energy consumption in a blending granulation production line?


Mr. Pan Zhirong: in the mixing and granulating production line, there are many links that can affect energy consumption. Firstly, the viscosity and thermal properties (specific heat, crystallization temperature, melting temperature and phase change heat, etc.) of the modified base material are followed by the hardware factors such as the length-diameter ratio of the main engine and the heating power allocation value (W). Thirdly, operating factors such as screw speed (n) and melt pressure (Pm) are applied. The upstream and downstream configuration power consumption (such as the choice of premixing mode, drying and conveying mode of finished particles) also accounts for a certain proportion.


PT: In view of the above links, how should the blending granulator reduce production energy consumption as much as possible, including the selection of equipment, and what should be paid attention to in the production process?


Mr. Pan Zhirong: How to select and match equipment to achieve energy saving can not be generalized. For example, many weightlessness metering units for raw material pre-mixing are of course energy-saving, but the investment is large at one time; for high-speed mixing units, the start-up current is high, energy consumption is high, but the ratio is accurate; for example, the length-diameter ratio of twin screw (L/D) directly affects the energy consumption and residence time (τ). Therefore, mixing granulator manufacturers should communicate with equipment suppliers to select the most suitable equipment for themselves.


As for the need to pay attention to the production process, it is necessary to understand the setting temperature of the main engine barrel in different districts, and the proportion of temperature control water cooling opening time in each district. But according to my experience, the squad leader and the main operator should implement the meticulous operation with the spirit of the ownership, minimize the accumulated value of the unplanned parking time within the whole line of 8h, which is the biggest energy saving and consumption reduction.


PT: In addition to energy saving, should blending granulator improve production efficiency and ensure product quality?

Mr. Pan Zhirong: in order to achieve energy saving and improve production efficiency and ensure product quality, mixing granulator manufacturers should do the following:


1. Upstream and downstream auxiliaries should be matched accurately and meet the level and grade required by the mixing granulator at the present stage.

2. The length-diameter ratio of twin-screw main engine should be selected accurately. Take the three series products of Keya as an example, the selection should be prudent (AK-universal series is the cheapest; SK-super series, imported transmission box configuration, its performance is high, screw efficiency is high, but the price is expensive; the newly launched domestic series of high-speed and high-torsion is the most cost-effective). The form of granulation should also be pinched accurately.


3.The most important variable factor to control energy saving and consumption reduction and improve product quality is to discharge high-efficiency "screw configuration" (or "screw configuration") after other factors (process formulation, pre-mixing, main engine and granulation) are fixed. Therefore, the mixing granulator should consult more friend factories, equipment manufacturers, process experts and depend more on the careful exploration and timely adjustment of mixing technicians.


PT: Which parts of the blending granulation production line belong to wearable parts? How should the mixing granulator improve the service life of these wear-out parts to reduce the cost as much as possible?


Mr. Pan Zhirong: screw elements (such as thread sleeves, mesh blocks, toothed discs, etc.), machine barrel, electric heater and cutter are the vulnerable parts in the mixing and granulating production line. In order to improve their service life, the mixing granulator should pay attention to the following points:


  1. Give priority to brand twin-screw if conditions permit.

  2. In the relatively concentrated spare parts factory, we should carefully select the best manufacturers.

  3. When a new batch of spare parts come in, we can consider replacing screw elements with less wear and even barrel with heavy wear area (emergency action);

  4. The movable and fixed knives of the cold pelletizer, and the blades for hot pelletizing (including air-cooled and water-ring) on the die surface should be purchased from the main machine factory as far as possible, or those with better reputation among the peers should be selected.


PT: The cost of granulation can be reduced by properly increasing the proportion of filler and recycled material. What experience does your company have in this field?

Mr. Pan Zhirong: When the proportion of ore powder is high, especially in the case of finer particle size, KY will often recommend the configuration scheme of barrel 2 (main) feeding and barrel 1 opening being changed to "back exhaust" to clients. This scheme works well in most cases and is welcomed by the blending granulator.


As for adding recycled materials, mixing granulator should add properly and master moderately; if adding barrel crushing materials, bottle materials and other recycled materials, the fineness of feeding pieces should be strictly controlled. Take AK equipment of Koya as an example: AK-73 requires that the three-dimensional size of fragments should be less than 11 mm x 6 mm x 4 mm (length x width x thickness). AK-63 requires less than 8 mm x 5 mm x 4 mm (length x width x thickness). If the Trend of "Bridging" is found, the grain size of the sheet material should be further refined (controlled by "coarse sieve" or even replaced with the bottom sieve spare parts of the crusher).