Advanced Imaging and Numerical Modelling of Segregation and Transport of Plastics in Fluidised Beds: Toward a Circular Economy for Plastics

流化床中塑料分离和传输的高级成像和数值模拟：迈向塑料循环经济

• 批准号: EP/T034327/1
• 负责人: Christopher Windows-Yule
• 金额: $ 43.31万
• 依托单位: University of Birmingham
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FT034327%2F1
• 关键词: Advanced; Imaging; Numerical; Modelling; Segregation

Plastic waste is one of the great environmental challenges of our time. Though efforts have been made to increase plastic recycling, the vast majority of waste plastics are still either incinerated or sent to landfill. Of the fraction of plastics that are notionally recycled, most are actually 'downcycled' into lower-grade products which, at the end of their life, cannot be recycled further and are still discarded, thus simply delaying the negative environmental impact, as opposed to reducing it.This project concerns a promising new process for converting waste plastics into petrochemical feedstock. The process involves the injection of waste plastics into a gas-fluidised bed of heated particles. Heat transferred to the plastic cracks long-chain molecules into shorter hydrocarbons which are then vaporised and extracted from the system, before being refined into valuable petrochemical products.While this emergent technology shows considerable potential, there remain significant impediments to its further development, upscaling, and widespread adoption. While the cracking & distillation processes are well-understood, the internal dynamics of the fluidised beds used remain largely unknown. Further, unlike for classical fluids, there exist no known laws governing the behaviours of fluidised granular media, meaning that these behaviours - and their variation with key system parameters - cannot be reliably predicted. Consequently, the specific influences of key parameters such as the system geometry, the positioning of inlets for the injection of plastics, the properties of the particles used in the heating process, and the effect of the vaporisation of plastics on the system's dynamics remain unknown. This, in turn, means that the development and optimisation of the process represents a slow, costly and high-risk task, as any change to the system must be physically implemented in a full-sized pilot plant, with no guarantee of success.This project aims to directly address these issues. Using cutting-edge experimental imaging techniques and computational modelling methods, we will attempt to gain a predictive understanding of the dynamical behaviours of multi-component gas-fluidised beds. This knowledge will allow us to establish scaling laws relating key system parameters mentioned above to crucial bed properties (e.g. recirculation rate, distribution of plastics, plastic residence time), as well as full numerical models, together enabling a) the informed and efficient operation and optimisation of current fluidised-bed-based recycling systems and b) the development of still more advanced systems. Experiments will be performed using a variety of methods, notably positron emission particle tracking (PEPT), which allows the motion of particles to be tracked, in 3 dimensions, even within large, dense, opaque systems, with high temporal and spatial resolution - making it ideally suited to the current application. The PI's significant experience with PEPT, and his position at the University of Birmingham, which houses Europe's only PEPT facility, will facilitate extensive use of the technique, including the development of specialised systems capable of imaging full-scale industrial pilot plants in situ.Experimental data obtained will be used to calibrate and validate numerical models coupling discrete element method and continuum fluid dynamics simulations so as to accurately reproduce the motion of both the particulate and gaseous components of the system. This numerical modelling will allow us to explore system modifications in a rapid, cost-effective and risk-free manner, circumventing the time, expense and risk associated with modifying or building new pilot plants, or sourcing, buying and testing new materials.We will work closely with leaders in the field and pioneers of the technique, Recycling Technologies, ensuring clear and direct pathways to impact, and thus expedited economic benefits for UK industry.

塑料垃圾是我们这个时代最大的环境挑战之一。尽管已经努力增加塑料回收，但绝大多数废塑料仍然被焚烧或送往垃圾填埋场。在名义上回收的塑料中，大部分实际上被“降级”为低等级产品，在其使用寿命结束时，无法进一步回收，仍然被丢弃，因此只是推迟了负面的环境影响，而不是减少它。该项目涉及一种有前途的将废塑料转化为石化原料的新工艺。该工艺包括将废塑料注入到加热颗粒的气体流化床中。传递到塑料的热量将长链分子裂解成较短的碳氢化合物，然后将其蒸发并从系统中提取出来，然后再精炼成有价值的石化产品。虽然这项新兴技术显示出相当大的潜力，但其进一步发展，扩大规模和广泛采用仍然存在重大障碍。虽然裂解和蒸馏过程是众所周知的，但所使用的流化床的内部动力学在很大程度上仍然未知。此外，与经典流体不同的是，不存在已知的控制流化颗粒介质行为的定律，这意味着这些行为及其随关键系统参数的变化无法可靠地预测。因此，关键参数的具体影响，如系统几何形状，塑料注射入口的位置，加热过程中使用的颗粒的性质，以及塑料蒸发对系统动态的影响仍然是未知的。这意味着工艺的开发和优化是一项缓慢、昂贵和高风险的任务，因为对系统的任何更改都必须在全尺寸的试验工厂中实际实施，无法保证成功。本项目旨在直接解决这些问题。使用先进的实验成像技术和计算建模方法，我们将试图获得多组分气体流化床的动力学行为的预测性理解。这些知识将使我们能够建立将上述关键系统参数与关键床特性（例如再循环速率、塑料分布、塑料停留时间）相关联的比例定律，以及完整的数值模型，从而实现a）当前基于流化床的再循环系统的明智和有效的操作和优化，以及B）更先进系统的开发。实验将使用各种方法进行，特别是正电子发射粒子跟踪（PEPT），它允许粒子的运动被跟踪，在3维，即使在大，密集，不透明的系统，具有高的时间和空间分辨率-使其非常适合当前的应用。PI在PEPT方面的丰富经验，以及他在伯明翰大学的职位，该大学拥有欧洲唯一的PEPT设施，将促进该技术的广泛使用，包括开发专门的系统，能够成像全，获得的实验数据将用于校准和验证耦合离散元方法和连续流体动力学模拟的数值模型，精确地再现系统的颗粒和气体成分的运动。这种数值模拟将使我们能够以快速、经济高效和无风险的方式探索系统修改，规避与修改或建造新的试验工厂或采购、购买和测试新材料相关的时间、费用和风险。我们将与该领域的领导者和技术先驱-回收技术密切合作，确保产生影响的明确和直接的途径，从而加快了英国工业的经济效益。

项目成果

Evaluation of coarse-grained CFD-DEM models with the validation of PEPT measurements

• DOI: 10.1016/j.partic.2022.12.018
• 发表时间: 2023-02-06
• 期刊: PARTICUOLOGY
• 影响因子: 3.5
• 作者: Che, Hanqiao;Werner, Dominik;Windows-Yule, Kit
• 通讯作者: Windows-Yule, Kit

A novel semi-resolved CFD-DEM method with two-grid mapping:methodology and validation

一种新型的双网格映射半解析CFD-DEM方法：方法与验证

• DOI: 10.22541/au.168930742.28338943/v1
• 发表时间: 2023
• 作者: Che H

Autonomous Digitizer Calibration of a Monte Carlo Detector Model through Evolutionary Simulation

通过进化模拟对蒙特卡罗探测器模型进行自主数字化仪校准

• DOI: 10.21203/rs.3.rs-1846231/v1
• 发表时间: 2022
• 作者: Herald M

Monte Carlo Model of the Large Modular Array for Positron Emission Particle Tracking

正电子发射粒子跟踪大型模块化阵列的蒙特卡罗模型

• DOI: 10.1109/access.2023.3255505
• 发表时间: 2023
• 期刊: IEEE Access
• 影响因子: 3.9
• 作者: Herald M

Monte Carlo model validation of a detector system used for Positron Emission Particle Tracking

• DOI: 10.1016/j.nima.2021.165073
• 发表时间: 2021-01-25
• 期刊: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT
• 影响因子: 1.4
• 作者: Herald, Matthew;Wheldon, Tzany;Windows-Yule, Christopher
• 通讯作者: Windows-Yule, Christopher