LCA of microwave plasma gasification

A robust mobile gasifier is developed in TU Delft regarding waste treatment. The setup offers more than 100% energy recovery and it can process different waste streams, plus toxic waste, and produce a synthesis gas. Furthermore, the synthesis gas can be upgraded to biofuels and/or generate power and heat. But does this reactor offers more environmental benefits that conventional waste treatment? Moreover, is it more profitable than them? Life Cycle Assessment (LCA) and Life Cycle Cost Analysis (LCCA) tools will be used to give insight in both issues and find identify places for improvement.

 

Over the years there has been growing interest in the use of gasification technologies as a way of solid waste treatment. However, regarding scaling up conventional forms of gasification the residual feedstock should be suitably homogenous in order to be used efficiently.  Plasma gasification provides an advantage in this situation as the process is proven to be able to process commercial, industrial and municipal waste.  The main product of the technology is a synthetic gas, rich in hydrogen and carbon monoxide, which can be used for electricity and/or heat generation, hydrogen, chemicals or fuels production.

Plasma gasification is a state-of-the-art technology, which takes place at 5000 OC, and is able to process and destroy toxic compounds, while it is converting them to valuable products. Experimental results at Technical University of Delft have showed an energy recovery of 184%, considering a feedstock conversion of approximately 20%. Furthermore, the results showed a low tar content in the gas produced, which is a significant advantage, as tar is a major problem of gasification technologies. The technology has gained interest in all around the world and, at the moment, facilities are under construction in UK, USA and Sri Lanka.

LCA is a methodology and tool which is continuously gaining attention as it can help evaluate products and services, and identify possible improvements. LCA has become very popular the last decade because its results can be presented and understood from decision-makers people with a moderate technical background. On the other hand, LCCA is another tool regarding the life cycle of a product or process, but its main focus is the determination of the most cost-effective option. Therefore, both tools can be coupled in order to assess the environmental impact and total cost/profit of a technology.

TU Delft has developed and proved microwave plasma gasification. The university has tested the technology by building its own plasma gasifier. There are currently two projects where the university is participating. One on microwave plasma gasification of solid biomass and the second one is called “Reinvent the Toilet”, which is part of the Water, Sanitation and Hygiene program, subsidized by the Bill & Melinda Gates Foundation. The former focuses on waste treatment in a small, robust and portable gasifier. Whereas, the latter concerns sustainable sanitation solutions to the 2.5 billion people worldwide who don’t have access to safe, affordable sanitation. It focuses on the processing of human waste to electricity generation, as shown in figure below. In the “Reinvent the Toilet” project various participants exist from TU Delft, such as IDE faculty with assistant professor J.C. Diehl and 3mE faculty with assistant professor P.V. Aravind and associates professors W. de Jong and G. Stefanidis.

 

In this MSc. graduation project the aim is to investigate whether TUD microwave plasma gasifier offers more environmental benefits (such as global warming, toxicity, acidification, eutrophication, etc.) and if it is more profitable than conventional waste treatments. The kinds of waste of preference are human waste, municipal solid waste, toxic industrial waste and/or e-waste. Whereas, the possible products can be electricity, chemicals, hydrogen or fuels. Main research questions are:

  1. Does plasma gasification offers more environmental benefits than conventional waste treatment?
  2. Which are the stages of the whole supply chain that can be improved and influence the LCA results significantly?
  3. Are there any bottlenecks in the whole supply chain?
  4. Is plasma gasification more profitable that already used technologies for the same purpose?
  5. Can the environmental footprint and/or total profit of such technology be influenced significantly by space/location details?

The MSc. Graduation topic will include modelling via an LCA software. Whereas, the LCCA analysis will be done in Excel. The systems’ boundaries will be cradle-to-grave; i.e. from the production of the biomass, until the utilisation of the synthesis gas and its waste.

Contact: Dr. ir. Wiebren de Jong Wiebren.deJong@tudelft.nl, Dr. Georgios Stefanidis G.Stefanidis@tudelft.nl, Dr. Guido Sturm G.S.J.Sturm@tudelft.nl, or George Tsalidis G.A.Tsalidis@tudelft.nl.

 

Suggested literature

Heidenreich, S., Foscolo, P.U., n.d. New concepts in biomass gasification. Prog. Energy Combust. Sci. doi:10.1016/j.pecs.2014.06.002

Heilmann, S.M., Jader, L.R., Sadowsky, M.J., Schendel, F.J., von Keitz, M.G., Valentas, K.J., 2011. Hydrothermal carbonization of distiller’s grains. Biomass Bioenergy 35, 2526–2533. doi:10.1016/j.biombioe.2011.02.022

Lakerveld, R., Sturm, G., Stankiewicz, A., Stefanidis, G., 2014. Integrated design of microwave and photocatalytic reactors. Where are we now? Curr. Opin. Chem. Eng. 5, 37–41. doi:10.1016/j.coche.2014.04.002

Sturm, G.S.J., Stefanidis, G.D., Verweij, M.D., Van Gerven, T.D.T., Stankiewicz, A.I., 2010. Design principles of microwave applicators for small-scale process equipment. Chem. Eng. Process. Process Intensif., Selected Papers from European Process Intensification Conference EPIC 2009 Venice17 - 18 June 2009 49, 912–922. doi:10.1016/j.cep.2010.07.017

Sturm, G.S.J., Verweij, M.D., Gerven, T. van, Stankiewicz, A.I., Stefanidis, G.D., 2013. On the parametric sensitivity of heat generation by resonant microwave fields in process fluids. Int. J. Heat Mass Transf. 57, 375–388. doi:10.1016/j.ijheatmasstransfer.2012.09.037

Tsalidis, G.-A., Joshi, Y., Korevaar, G., de Jong, W., 2014. Life cycle assessment of direct co-firing of torrefied and/or pelletised woody biomass with coal in The Netherlands. J. Clean. Prod. 81, 168–177. doi:10.1016/j.jclepro.2014.06.049

Willis, K.P., Osada, S., Willerton, K.L., 2010. Plasma Gasification: Lessons Learned at Eco-Valley WTE Facility 133–140. doi:10.1115/NAWTEC18-3515