Microwave Heating

Management of the rapidly growing and highly hazardous electronic waste stream is one of the main environmental challenges currently facing Canada, and most other countries. According to the United Nations Environment Programme (UNEP), between 20 and 50 million metric tons of e-waste are disposed of globally every year, and this is predicted to increase to between 40 and 70 million tons per year by 2015. Within Canada, volumes of e-waste are reportedly increasing by 4% each year. One source has estimated that more than 5 million computers and monitors alone are thrown away annually by Canadian households and businesses. These form only part of a much larger e-waste stream that includes mobile phones, televisions, office equipment and white goods.

The safe and efficient management of the e-waste stream presents particular challenges due to the complex nature of most e-products, which typically include high levels of hazardous substances such as lead, mercury and cadmium. Environmental hazards such as toxic emissions also arise as a by-product of e-waste disposal or recycling processes. However, many e-waste products also contain valuable and scarce materials such as gold, silver, platinum and copper, and their effective recovery for resale and reuse represents a potentially lucrative business activity.

Recycling methods currently in use are not particularly efficient or cost-effective. The processes involved are still quite labour-intensive, involving dismantling products by hand to extract valuable components, or remove harmful substances before the waste is sent for end-processing using automated methods. New techniques may improve the efficiency of recycling and help ensure that the high-value outcomes of recycling outweigh the costs involved.

Although research into the heavy oil problems is not at an early stage, a lot remains to be investigated about properties and upgrading methods of this material based on studying different papers and literature reviews related to heavy oil. Upgrading methods of heavy oil were studied by different research groups during this century; various methods have been used and different parameters affected the process such as temperature of reaction, heating rate, quenching time, and oil composition. Recently, microwave heating method attracted scientists because of its benefits over the conventional heating.

microwave heating has been used in different processes like pyrolysis of biomass, plastic waste, polymers and etc. Despite these interesting properties of microwave heating pyrolysis processes, there is the lack of an efficient method for upgrading heavy oil to high quantity and quality products.

In the current work, we propose a new microwave heating method for heavy oil upgrading with the use of SiC@HZSM-5 as an MW-absorbent/catalyst of microwave irradiation.

We aim to develop an optimized process for the elimination of heavy metals, such as Ni & V, and sulfur compounds from crude petroleum oil using microwave heating and a demetallization desulfurization reagent (DMDSA). The crude oils are known as weak microwave receptors that do not interact with electromagnetic waves. However, existing metals in the crude and the employed DMDSA have a high interaction with microwaves. Therefore, obtaining local hot spots close to the metal compounds is possible while the bulk temperature is not changed significantly, which leads to lower energy requirement for the elimination process compared to conventional heating. The target elements interact with DMDSA and are converted to water-soluble from stable oil-soluble compounds that can be separated by washing. The kinetic model of such a process will be crucial to obtain the optimum design and operating conditions. Additionally, parameters, such as residence time, DMDSA dosage, and microwave power, have a significant impact on the technical and economic performance of the developed process. The optimum process design and the economic performance will clarify the possibility of scale-up of such a process by comparing with conventional demetallization and desulfurization units in the petroleum refinery industry.

Natural gas (80-95 vol.% methane) is a crucial energy source and an important feedstock for the synthesis of valuable chemicals. The current utilization of natural gas is mostly directed to heat and electricity generation. The efficient conversion of natural gas to value added chemicals increases the scope of its utilization, however, it comes with major technical and environmental obstacles. Conversion of methane to value-added chemicals such as methanol and olefins is only practiced through syngas production step followed by other technologies. Nevertheless, efficient direct conversion of methane to chemicals is challenged by low selectivity of desired products at high methane conversion and rapid catalyst deactivation. Methane conversion via microwave technique is enhanced as compared to conventional pathway. This enhancement is attributed to thermal effects: hotspots formation and selective heating. As a result, contrary to the expected trend of selectivity decrease with conversion increase, both values can be increased together in microwave heating-assisted operation. Therefore, the main objective of this project is to improve simultaneously methane conversion and C2 hydrocarbons selectivity in the direct non-oxidative conversion of methane. The investigation spans thermal pathway (main product: C2H2) and catalytic pathway (main product: C2H4 and C2H6). The investigations are to demonstrate a microwave-assisted DNMC process with a performance surpassing conventional heating approaches, identifying, and validating the performance of fabricated catalysts accompanied with kinetic studies, demonstrate the process energy requirements, techno-economic potential, bottlenecks and uncertainties for advancing technology readiness level.

In our current modern era, the alarm of global warming and accelerated greenhouse gas emissions are pressing concerns. Globally, we add 51 billion tons per year of greenhouse gases to the atmosphere. Over the last 30 years, carbon dioxide (CO2) emission has increased more than 60%. CO2 and methane (CH4) emissions are principal reasons for global warming and climate change. Currently, 6% of the natural gas consumption and 2% of the coal consumption is directly related to hydrogen (H2) production. Hence, developing a green process of H2 production is a hard row to hoe. Syngas, i.e., a mixture of hydrogen (H2) and carbon monoxide (CO), is a critical source of hydrogen production. Globally, steam methane reforming process, where CH4 and H2O are converted to syngas, produces more than 50% of the required H2. Therefore, developing a green and sustainable process of syngas production is inevitable. I am working on microwave assisted dry reforming of methane, where CH4 and CO2 are converted to syngas and microwave heating, i.e., a green and sustainable heating technology prepares the required heat energy of the reaction. This game changing solution has the potential of being a turning point in H2 production industry.

Due to industrialization and population growth, demand for energy sources has been increasing during the last century. Fossil fuels as a common source for supplying energy for different applications (e.g., industrial plants, households) release a tremendous amount of CO2 to the atmosphere and intensify global warming. Replacing fossil fuels with renewable energies can be a promising solution to tackle CO2 emissions. However, renewable energies are intermittent, and they need to be stored efficiently for usage when/where required. Ammonia can be a suitable medium for storing green hydrogen (i.e., hydrogen produced using renewable electricity and water electrolysis). Its transportation infrastructure is well established, and its storage cost is three times lower than hydrogen. This project aims to produce ammonia (as a hydrogen storage medium) under efficient operating conditions using green hydrogen and nitrogen from the air using MW-heating assisted chemical looping ammonia synthesis technology.

Cold plasmas at atmospheric pressure are favorable environments for inducing physicochemical phenomena of great interest for technological applications. The present project consists in developing plasma sources to process nanomaterials. At least two sources will be developed and tested: 1) plasmas in bubbles in a liquid in which the nanoparticles are located and 2) plasmas in a fluidized bed. Part 1) will be developed at UdeM while part 2) will be developed at Polytechnique Montréal. First, the materials of interest are phosphate particles. The candidate will characterize the different plasma sources and characterize the nanomaterials in order to identify the modifications made by the plasma in order to control them.

In my PhD project, I use microwave-assisted pyrolysis technology to recycle polystyrene into its monomer, styrene. This technology subjects polymer melt to microwave irradiation in a stirred-tank reactor. To understand the effect of different operating conditions on involved physics in this process and consequently, the impact of these parameters on the reactor’s performance the hydrodynamics of reactor must be investigated. Radioactive Particle Tracking (RPT) technique is a powerful tool to study the hydrodynamics’ of opaque systems. By implementing the experimental data, I will develop a mathematical model to predict the impact of hydrodynamics on polystyrene pyrolysis using a microwave-assisted reactor.