Syngas success story
Ze-gen Inc. is using material—such
as non-recyclable plastic and carpet fiber that would typically end up
landfills—as feedstock in its liquid metal gasification
technology and is now
successfully producing high quality syngas.
The raw material used in the Ze-gen process is mostly biomass material and is processed to very specific quality standards by the company's suppliers. The company then blends the material in accordance with its proprietary formula.
Many success stories in alternative
energy have resulted
from finding value in waste streams or turning a challenge on its head
reveal an opportunity. The development of liquid metal gasification
by Boston-based Ze-gen Inc. is a prime example of that.
long been known as an unwanted byproduct in ore purification processes
steel production. Ze-gen investigated what caused the production of
how it could be enhanced instead of diminished. The company discovered
liquid metal could be used as a catalyst to manufacture high volumes of
energy-rich syngas from material typically discarded in landfills.
there are many well developed and proven gasification and pyrolysis
already in existence, Ze-gen seems to have found its own niche in the
metal gasification realm.
think there are a lot of people that are doing what we are
doing,” says company
founder and CEO, Bill Davis. “I know of a couple of companies
that work with
other metals and other feedstock under different conditions, but I
of anyone who is approaching this the way we are. I would say that it
is a very
old technology idea, and we have a new application for it.”
production of syngas when organic impurities come into contact with
liquid metal has been an ongoing challenge for metal purifiers for
The unwanted gas is typically flared.
involved in ore purification discovered a long time ago that liquid
as a catalyst and causes organic impurities to bubble up as
Davis. “We thought to ourselves that if we just invert the inputs
of the process, we can actually end up with a good approach to making
a low cost.”
words, the company has developed a process where adding a specific
both inorganic and organic waste products to a liquid copper bath, in
of about 2300 degrees Fahrenheit, produces an energy-rich syngas stream.
chose liquid copper as the catalyst because Davis says it is somewhat
forgiving. It can be easily converted from a solid to a liquid and back
solid, which is not easily accomplished with other metals like iron,
and it has
a low melting point.
“We like the
combination between the melting point of copper and the flexibility to
manipulate the pre-conditions of the metal,” says Davis.
method can be broken down into three steps. These are feed and material
handling, liquid metal gasification, and gas cleanup and conditioning.
material used in the Ze-gen process is mostly biomass material,
plastic and carpet fibre that would typically end up in landfills. When
processed to very specific quality standards by the company’s
gasification of these materials can deliver a high quality syngas.
fairly rigid expectations around the pre-processing of feed
Davis. “In fact, our commercialization efforts don’t
involve working with mixed
waste, but rather involve working with individual waste streams and
blending them ourselves in accordance to our proprietary formula. The
is not blended when it comes to us, so this allows us to maintain very
control over the chemical composition of what is coming into our
that the technology will work with a variety of feedstocks, but for the
being, Ze-gen is focusing on those that will most easily lead to
gas, propane, or electricity can be used initially to melt the copper
After initial start-up, limited external energy input is required to
metal in a molten state, because once the feedstock is added, the
reactions within the chamber provide much of the ongoing heat
the process. The internal temperature increases rapidly once the waste
comes into contact with the liquid bath, resulting in an energy
process. Oxygen is also added as part of the conversion process,
the feedstock being used.
investing in the development of this gasification process, Ze-gen took
look at existing gasification technologies and the challenges that each
They discovered that what had been developed to date were either low
or high temperature gasifiers. The problem with low temperature
the formation of tar in the syngas. The problem with high temperature
gasification is the high energy costs associated with producing the
therefore phrased the problem as, how do we produce syngas at a low net
operating cost that is free of tar,” says Davis. “It led us
to the realization
that liquid metal could be used as both a heat sink and a catalyst. It
parasitic energy losses associated with the production of syngas. Also,
catalyst and because of the temperatures we gasify at, we avoid tar
That is essentially how we ended up with our technology strategy.”
Ze-gen has developed a process where adding a specific recipe of both inorganic and organic waste products to a liquid copper bath, in the range of about 2300 degrees Fahrenheit, produces an energy-rich syngas stream.
Ze-gen proposes to use its syngas to
produce renewable heat
and electricity in the 5 to 20 MW range. Its gasification and power
could be attached to individual plants or clusters of industries to
eliminate their dependence on natural gas or liquid fuel oil to
Davis says that the cost of using the syngas would be comparable to
at today’s low prices, but would still be less than half the cost
based on the company’s findings from its demonstration plant at
Waste Services in New Bedford, Massachusetts, which it established in
has been able to achieve 90 percent carbon monoxide and hydrogen
in the syngas, which is well above its initial 70 percent targets. The
also estimates that this facility has been able to convert about 300
feedstock per hour into approximately 1.66 MMBtus per hour of syngas.
now at the stage of proving that the process can deliver high quality
a consistent basis.
produces slag and air emissions as byproducts. The small amount of slag
produced can be used as aggregate for roadways.
“With respect to the emissions,
we are installing a wide
variety of state-of-the-art back end emissions systems after combustion
syngas,” says Davis. “As a result of that, we are
considered a minor source of
emissions for a commercial plant—well within all the local,
state, and federal
not only interested in proving its technology, it has also spent
time planning how to roll out the technology in such a way that it
economic benefit to the company and to its customers. Therefore, in the
term, Ze-gen plans to build, own, and operate all its commercial
earning income from providing heat and power as well as from tipping
disposing of waste that would normally go to the landfill.
“We’re in a
space where there is a revenue stream on the front end and on the back
says Davis. “You really want to optimize each of those.”
is also focused on providing heat and power to specific niche markets.
to break ground on its first $20 million commercial syngas production
7 MW power facility in Attleboro, Massachusetts, in spring 2011, with
construction expected to take about nine months. The plant will provide
to industrial customers at the Attleboro Corporate Campus. Davis says
actually approached by a group of business owners from the industrial
were eager to work with the company to establish its first commercial
“We are not looking to build
plants that require 1000 tons
of waste a day, where waste has to be moved around a lot, and we are
lot of traffic,” says Davis. “We are looking for small
that we can build inside the fences of industrial parks. Making excess
and then having to dump it onto the grid at wholesale prices is really
proposition for us.”
that managing the economics of commercialization is a very important
consideration that will require “some surgical approaches to
simply to be able to compete with the price of natural gas.
effectively sized the Attleboro facility to the base load demand on
says. “But I think the opportunities are enormous, and if you
think about waste
as a global problem, and you look at certain parts of the world, I
there is a very significant opportunity for small distribution
convert waste into a resource.”
to being able to provide a complete gasification and heat/power
package, Davis says there could be situations in the future where a
already has a boiler and Ze-gen would simply provide the fuel to create
for power generation or as part of an industrial process.
term, Ze-gen plans to license the use of its liquid metal gasification
technology as well as continue to operate its own gasifiers. It also
potential opportunities in the sale of hydrogen and potential use of
downstream developers of liquid biofuels.