Extrusion Uniformity Optimization for Shaping Channel Design in Large-Scale Die-Plate of Underwater Pelletizing

Abstract

As an important component of large-scale extruder system for polymer material, Die-plate can be regarded as the final determinant for pelletization uniformity. Polymer melt was shaped in shaping channels and extruded from die-holes from Die-plate and then be diced. The design of shaping channels directly influences the uniformity for polymer-melt extrusion pressure and extrusion velocity of different die holes. In this paper, a three-dimensional flow model for polymer flow in Die-plate channel was presented, and then finite element simulation was used to analyze the distribution of extrusion velocity in each die-hole. Based on simulation result, a BP neural network model was applied to analyze the relationship between geometry factors of Die-plate, such as length of shaping channels, die hole extrusion velocity distribution, and extrusion uniformity. This optimization method can be used in the design of Die-plate to improve effect and quality of actual polymer production and processing.

A review: research progress of flux pellets and their application in China

“…It also can be seen distinctly from Figure 13 that from May 2019 to March 2020, the pellet rate in BF burdens was step-by-step increased when the low-silicon basic pellets started to be used. The maximum value of the pellet rate in BF burdens have reached 58% and their average was 54.66%, which also demonstrates that the use of flux pellets would further decrease the proportion of sinter in BF burdens from 67% to 43% and greatly change the burden structure of blast furnace [8]. Figure 14 shows the variation of fuel consumption index at high pellet rate, which can indicate that the coke ratio kept at around 290 kg t −1 and the fuel ratio decreased from previous 506 to 484 kg t −1 with the pellet rate increasing.…”

“…It is worth mentioning that in order to meet the requirement of uniform distribution of pellet in belt roasting machine, Shougang Jingtang Corporation have independently designed and developed the combined distribution process of the 'reciprocating belt conveyor + wide belt + Bi-layer distribution', which effectively improved the distribution accuracy of pellet and realised dynamic and accurate distribution. The trapezoidal distribution technology with thick material bed was used as a major distribution method of pellet, which could decrease the fuel consumption (Coke oven gas) by 10% and increase the production capacity of finished pellet by 18% [8,122]. With the pellets proportion increasing, the belt roasting machine in China will gradually develop towards large scale, automation and intensification.…”

“…Moreover, there was almost no dioxin formed during the production of flux pellets and the process energy consumption could be reduced by 11.9% (17.11 kgce t −1 ), which will greatly reduce the emission of pollutants and the cost of production [2,6,7]. For instance, the emission content of flue gas, particulate matter, SO 2, and NO x was 1720 m 3 t −1 , 2, 8 and 31 mg m −3 when the 504 m 2 belt roasting machine of Shougang Jingtang Corporation was used to produce the lowsilicon basic pellet, which was far below the pollutant emission indexes of sinter production [8]. Therefore, the proportion of pellets in BF burdens has been increased year by year in China due to their advantages like high iron grade, low gangue content, uniform size and shape, high compressive strength, low disintegration and less pollution during production.…”

Mechanism Research on Pelleting Process and Block Self-Healing of Mixture Recycled Plastics in Die-Plate

“…Dang Shasha and Ren Shixiong studied the temperature distribution law of the die-plate [11][12]. Xiaofeng Liu analyzed the relationship between pelletization quality and operation uncertainty in die-plate [13][14]. Gupta provided a simulation to denote that the length of shape channel can change the extrusion uniformity [15].…”