Potential of pyrolysis processes in the waste management sector

The fundamentals of pyrolysis, its latest developments, the different conditions of the process and its residues are of great importance in evaluating the applicability of the pyrolysis process within the waste management sector and in waste treatment. In particular the types of residue and their further use or treatment is of extreme interest as they could become the source of secondary raw materials or be used for energy generation in waste treatments. The main area of focus of this paper is the investigation of the link between the pyrolysis conditions, the chemical and mineralogical composition of their products and the benefits of pyrolysis in the waste management sector. More specifically the paper covers the fast, intermediate and slow pyrolysis of organic waste and mixtures of inorganic and organic waste from households. The influence of catalysts during fast pyrolysis on the product yield and composition is not being considered in this review.This reported work was conducted as part of the “Design Optimisation of the HERU Waste Treatment System” project in Brunel University London that was funded by Manik Ventures Limited

Municipal waste management systems for domestic use

© 2017 The Authors. Every year, the average citizen of a developed country produces about half a tonne of waste, thus waste management is an essential industry. Old waste management systems based on the collection of mixed/ sorted waste and transporting it a long way to disposal sites has a significant negative impact on the environment and humans. This paper will review the available waste management systems for house- holds. Biological methods (such as composting or anaerobic digestion) and physicochemical methods (such as burning or pyrolysis) of waste utilization will be considered from the householder’s point of view. The most important features of each system will be discussed and compared. Municipal waste management systems for domestic use could eliminate or significantly reduce the stage of waste collection and transportation. Additionally, they should not require special infrastructure and at the same time should allow garbage to be changed into safe products or energy sources with no harmful emissions. The aim of the work is to identify the best available waste disposal systems for domestic use.This reported work was conducted as part of the“Design Optimisation of the HERU Waste Treatment System”project that wasfunded by Manik Ventures Limited Project ID: 10300

An overview of chemical additives present in plastics: Migration, release, fate and environmental impact during their use, disposal and recycling

Over the last 60 years plastics production has increased manifold, owing to their inexpensive, multipurpose, durable and lightweight nature. These characteristics have raised the demand for plastic materials that will continue to grow over the coming years. However, with increased plastic materials production, comes increased plastic material wastage creating a number of challenges, as well as opportunities to the waste management industry. The present overview highlights the waste management and pollution challenges, emphasising on the various chemical substances (known as “additives”) contained in all plastic products for enhancing polymer properties and prolonging their life. Despite how useful these additives are in the functionality of polymer products, their potential to contaminate soil, air, water and food is widely documented in literature and described herein. These additives can potentially migrate and undesirably lead to human exposure via e.g. food contact materials, such as packaging. They can, also, be released from plastics during the various recycling and recovery processes and from the products produced from recyclates. Thus, sound recycling has to be performed in such a way as to ensure that emission of substances of high concern and contamination of recycled products is avoided, ensuring environmental and human health protection, at all times

The Yield Prediction of Synthetic Fuel Production from Pyrolysis of Plastic Waste by Levenberg–Marquardt Approach in Feedforward Neural Networks Model

The conversion of plastic waste into fuel by pyrolysis has been recognized as a potential strategy for commercialization. The amount of plastic waste is basically different for each country which normally refers to non-recycled plastics data; consequently, the production target will also be different. This study attempted to build a model to predict fuel production from different non-recycled plastics data. The predictive model was developed via Levenberg-Marquardt approach in feed-forward neural networks model. The optimal number of hidden neurons was selected based on the lowest total of the mean square error. The proposed model was evaluated using the statistical analysis and graphical presentation for its accuracy and reliability. The results showed that the model was capable to predict product yields from pyrolysis of non-recycled plastics with high accuracy and the output values were strongly correlated with the values in literature

Design and limitations in polymer cracking fluidized beds for energy recovery

The rise in the manufacturing of plastics increases the waste streams generated. The most popular way to treat plastic that cannot be recycled is to use energy recovery methods or landfill the waste. As plastic is nonbiodegradable, landfilling causes vast environmental problems, and therefore, waste polymer energy recovery techniques are of great importance. Pyrolysis has advantages as all mixed plastics can be reduced back to petrochemicals. Fluidized beds have useful characteristics for energy recovery. They have an economic advantage in industrial operations due to low maintenance costs when compared to other reactors. Fluidizing beds provide flexibility in the operation that makes it possible to use various fluidizing agents and process conditions. Fluidizing beds were identified to be the best reactors for catalytic plastic pyrolysis as they provide large contact surface for the reaction to happen. The fluidizing beds have some limitations; the bed particles can erode the walls of the vessels, and the beds are sensitive to fibers, high amounts of metals, and fillers. Long-term stable operation of the fluidized bed can worsen the quality of the fluidization, and some operation conditions may cause defluidization. The paper reviewed the use of fluidization for energy recovery, and discussed its advantages and limitations. The fluidizing beds are promising reactors for energy recovery due to the flexibility of the operation. However, further investigation is required to understand and improve the quality of fluidization, ways to avoid defluidization, and parameters affecting the performance of the fluidised beds for energy recovery