History of Gasification of Municipal Solid Waste through the eyes of Mr. Hakan Rylander

This is an excerpt from Let's speak about Waste To Energy..., an interview conducted by Antonis Mavropoulos and published on his Global View of Waste Management Blog****

Mr. Hakan Rylander, CEO Sysav Company Group

Mr. Hakan Rylander is a former President of International Solid Waste Association (ISWA)  and the current CEO of the SYSAV Company Group. He is one of the most experienced WtE engineers I know, involved in all different phases and aspects of a WtE facility. SYSAV is a role model company in WtE.  Mr. Hakan has held many other key-positions e.g. Chairman of the ISWA WtE Working Group, Swedish Representative in the Nordic Association of Waste Management, Chairman of the Scania Society of Engineers. Currently Hakan is also running the R&D Committee of Avfall Sverige.

Antonis Mavropoulos: What can we expect from the (Waste-to-Energy, WTE) technology in terms of improvements?

Hakan Rylander: - to reduce and minimize the amount of bottom ash. (More here)
- to develop a safe and environmentally correct way of final handling of the flue gas cleaning residues and to recover as much as technical and economically possible of the metal content in these residues and in the bottom ash (More here)
- to increase the electrical efficiency in the waste-to-energy plants. (More here)

About the History of Developing Gasification Technology for Municipal Solid Waste (MSW)

Last but not least, in a recent discussion I heard, probably for the 100th time in last two years, that incineration is dead and that gasification and plasma pyrolysis will soon substitute all incineration plants. What is the current status of those technologies? Are they applicable for Mixed MSW? Are there commercial applications and operational experiences? After all,  is it something we can trust?

Antonis: A lot of people say they are promising and they are more environmental friendly than incineration...?

Hakan: Well,

I guess I have heard the same thing at least as many times as you Antonis.

I remember when I joined the business in the 1970-ies that there was a big belief that gasification, pyrolysis and the plasma technology would be the “salvation” of the waste problem. A number of companies introduced gasification and pyrolysis technologies, just slightly different from each other. All the different methods had worked in a very good way when testing them in a small scale, feeding the reactors with a small, very well prepared amount of waste each time. The problems came when scaling up the technology.

A number of (gasification) plants were built in Europe and a number of efforts were done to successfully scale up the technology. However, it didn´t work anywhere unless you had a very very homogenous input of fuel to the reactors. Waste is not a homogenous fuel. It has so far turned out to be too heterogenous to be able to treat in a gasification or pyrolysis process, irrespective of how you pre-treat the waste. It is absolutely not applicable for mixed MSW with today's technology. Another very negative factor is that the energy balance very often has turned out to be negative.

It would, from an environmental point of view, be an excellent method if it worked, with low emissions and with a very small and environmentally safe residue, but unfortunately the situation today and the experiences are the same today as almost 40 years ago, even if there have been and still are efforts to introduce gasification and pyrolysis on the market.

When planning for the two new furnaces in the Sysav-plant there were proposals and some efforts that we should change from conventional grate incineration to gasification. I said absolutely “No”, but to be fair to those who believed that gasification was the best technology we decided to carry out a study and a comparison between the two technologies. The answer was very clear: gasification would result in a negative energy balance. I am happy to say that we made the right decision, our results and experiences from the grate technology gives the answer.

I absolutely don´t want to be negative, it would be fantastic if the gasification and pyrolysis technology will develop in such a way that you can use it for MSW , with a clear positive energy balance and working in a safe way for those working at the plant.

I remember when I as a young person in the waste business, full of belief in new methods and technologies, in the middle 1970-ies participated in a very good conference in Antwerp about waste management. There was a whole session about gasification and pyrolysis and I was full of enthusiasm, expecting a lot from the different presentations. On the way in to the conference room I walked beside an older gentleman and colleague from Germany. I told him about my expectations and he looked very friendly upon me telling me that he had started to work with R&D within waste management already in 1922 at the Batelle Institute in Frankfurt, and the task was to gasify/pyrolyse waste in a better way than could be done in a waste incineration plant. He told me that they without any success had been trying to do so and that he still had very little faith gasification/pyrolysis could be developed and turn out to be a successful technology for waste.

I was of course very disappointed to hear this, but still believed it was the technology for the future handling of waste. The bad experiences coming up very soon after that conference and all the failures and unsuccessful efforts since then has made me very skeptical.

I believe there is a long way still to go, but we shouldn´t give up our efforts."