Turning landfill into energy

March 7, 2018 by Jon Cartwright, From Horizon, Horizon: The EU Research & Innovation Magazine
Advanced gasification methods can turn any waste except metal and rubble into fuel for electricity. Credit: Pixabay/ Prylarer

Landfill is both ugly and polluting. But a new breed of technology promises to make it a thing of the past, transforming a huge portion of landfill material into clean gas.

It's thanks to a process called , which involves turning carbon-based materials into gas by heating them to a high temperature but without burning them. The gas can be stored until it is needed for the generation of electricity.

According to its developers, advanced gasification can be fed by plastic, biomass, textiles – just about anything except metal and rubble. Out of the other end comes syngas – a clean, easily combustible gas made up of carbon monoxide and hydrogen.

The basics of the technology are old. Back in the 19th century, gasification plants existed in many of Europe's major cities, turning coal into coal gas for heating and lighting.

Gasification waned after the discovery of natural gas reserves early last century. Then in the past 20 years or so, it had a small renaissance, as gasification plants sprung up to process wood.

In a new, advanced implementation, however, a much broader range of materials can be processed, and the output gas is much cleaner. "Gasification is clearly gaining a lot of traction, but we've taken it further," said Jean-Eric Petit of French company CHO Power, based in Bordeaux.

Gasification

Gasification involves heating without combustion. At temperatures greater than 700°C, a lot of hydrocarbon-based materials break down into a gas of and hydrogen – syngas – which can be used as a fuel.

For materials such as wood, this is relatively straightforward. Try it with other hydrocarbon materials, and especially hard-to-recycle industrial waste, however, and the reaction tends to generate pollutants, such as tar.

But tar itself is just a more complex hydrocarbon. That is why Petit and his colleagues have developed a higher temperature process, at some 1200°C, in which even tar is broken down.

The result is syngas, which, unline other thermal processes, does not create dangerous pollutants. In fact, it is high-quality enough to be fed directly into high-efficiency gas engines, generating electricity with twice the efficiency of the steam turbines used with conventional gasification, says Petit.

CHO Power has already built an advanced gasification plant in Morcenx, France, which converts 55,000 tonnes of wood, biomass and industrial waste a year into 11 megawatts of electricity.

The gas produced by CHO Power's gasification process is refined at 1,200°C in their turboplasma facility (left) so that it can be used in a gas engine (right) to generate electricity. Credit: CHO Power

In December the EU announced that the company will receive a €30 million loan from the European Investment Bank to construct another plant in the Thouarsais area of France.

The company is not the first to attempt advanced gasification on a commercial scale. But, said Petit: "We think we're the first to crack it."

CHO Power's gasification plants still need to have waste delivered to them. Hysytech, a company in Torino, Italy, however, plans to bring gasification to industry's door.

The idea is to build a small gasification plant, processing at least 100 kilos per hour of waste, next to any industrial plant that deals with hydrocarbon materials – a textiles or plastics manufacturer, for instance.

Then, any waste the industrial plant generates can be turned straight into syngas for electricity generation on site, avoiding the emissions associated with transporting waste to a distant gasification plant.

Small-scale

The problem is that, historically, gasification on this scale has cost too much to be in an industry's interests. But Hysytech believes it has made small-scale gasification cost effective, by developing a novel reactor known as a fluidised bed.

When waste materials are fed into this reactor, a fluid is passed through them to create an even temperature and to allow the gas to leave easily. If the materials need a lot of time to turn to gas, they remain in the reactor until they are gasified, but the fluid can be sped up if the turn to gas quickly.

The result, for smaller at least, is a more efficient and cost-effective process. "Our system is designed and built to operate year-round with a good efficiency, easy operation and little maintenance," said Andrés Saldivia, Hysytech's head of business development.

Hysytech has built a pilot plant that has about one-tenth the envisaged output, processing 10 kilos of waste an hour into syngas. Currently, its engineers are constructing a full-sized demo plant that will include an additional power-to-gas system, to link the gasification to surplus energy from wind turbines and solar panels so the energy is not wasted.

With this additional system, the surplus energy is used to split water into hydrogen and oxygen. Using a carbon source, this hydrogen is then converted into methane, which can be used like everyday natural gas.

"Our goal is to have it ready for the market (by) 2019," said Saldivia.

Explore further: Modular drop-in fuel technology to boost bio-share of oil refineries

Related Stories

New process provides renewable fuel

December 17, 2015

Luleå University of Technology is the first in the world to produce renewable fuels from pyrolysis bio-oil in its facility LTU Green Fuels. Pyrolysis bio-oil is produced by rapidly heating the forest residues in an oxygen-free ...

Recommended for you

A novel approach of improving battery performance

September 18, 2018

New technological developments by UNIST researchers promise to significantly boost the performance of lithium metal batteries in promising research for the next-generation of rechargeable batteries. The study also validates ...

Germany rolls out world's first hydrogen train

September 17, 2018

Germany on Monday rolled out the world's first hydrogen-powered train, signalling the start of a push to challenge the might of polluting diesel trains with costlier but more eco-friendly technology.

Technology streamlines computational science projects

September 15, 2018

Since designing and launching a specialized workflow management system in 2010, a research team from the US Department of Energy's Oak Ridge National Laboratory has continuously updated the technology to help computational ...

2 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

WEFortune
not rated yet Mar 07, 2018
Engineers in NH have designed a trash to liquids plant using landfill materials and producing synthetic materials. Unfortunately, people are more interested in investing in hi-tech than getting rid of landfills. indust.consult@rcn.com
Eikka
5 / 5 (1) Mar 07, 2018
But, said Petit: "We think we're the first to crack it."


Pun intended.

Though there's the remaining question of how they deal with the PVC, PTFE, other chloro-fluoro materials and sulfur containing matter in the waste stream if they are going to just dump mixed landfill waste into the reactor?

At very high combustion temperatures, the fluorine comes out as HF which dissolves into rainwater to form Hydrofluoric acid, which is a bit nasty. Traditional waste incinerators need elaborate smoke stack scrubbers because of this.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.