This is a strange question for the Green Machine to
ask. I really think both behemoth
companies offer fantastic combined cycle natural gas power generation
facilities. The question relates to a
small niche market of capturing waste carbon monoxide (CO) from steel mills.
GE claims to be able to produce electric power from such
waste off gas streams
Siemens has partnered with LanzaTech (who I have opined
greenwash) to use this very same waste stream to produce ethanol via a
biological reaction.
Jim Lane who runs a pretty mediocre (thermodynamically
speaking) web site has added fuel to this fire.
I was in contact with Siemens and do have emails from the
company. As Jim Lane published his
article I now have to provide my comments to the comments that Siemens and
LanzaTech have given to Jim Lane and that he has published. Note most of these comments were also given
to me by Siemens. I have never had any
direct discussion with LanzaTech. Here
is the content of an email I sent to Norbert Aschenbrenner at Siemens that was
sent to him yesterday. Siemens comments
are followed by my comments in italics.
“After teaming
up with several experts from Siemens and LanzaTech I can give you the following
answer:
The fact that
many of these industrial facilities could be making electricity with steam
cogeneration now, but are not, tells the story. The question then, with respect
to steel mill waste gas, is what provides the highest marginal value,
financially/environmentally/socially. Customers and partners have invested in
LanzaTech because they realize these three vectors
(economics/environment/social good) are aligned in the LanzaTech process, where
ethanol production provides a higher IRR, lower CO2 emissions, and lower
SOx/NOx/particulate emissions when compared to electricity production.
Norbert looking
at this response it already is apparent that the link I referred to that
started the conversation has incorrect information.
You state that
the mills are not using the CO or the hydrogen in the above argument But your
link refers to mills that are generating electricity with the offgas and how they
will lower their CO2 emissions by one third by converting to the LonzaTech
process. “A steel mill that is currently
using its off-gases to generate electricity could lower its CO2 emissions by a
third using the new fermentation process.”
This is the concern
I expressed to you that this statement is incorrect. I will elaborate further
on that this statement is incorrect and should be rectified.
They also
realize that ethanol is just one of many chemicals that LanzaTech can produce,
which can be used both as chemical intermediates and fuels. When the products
of gas fermentation are used as chemical intermediates (rather than fuels) the
LanzaTech process offers an opportunity to sequester waste carbon in the form
of durable products, produced from high-value chemicals that create even higher
returns from these gas streams.
Yes CO and if
there is some hydrogen, although there is not much in a Chinese steel mill,
could produce durable chemicals that hold carbon. In fact I have
proposed that steel mills be combined with chemical plants that produce
polycarbonate or isocyanates (PMDI) as these chemicals use CO as a
feedstock. Of course it would be by a traditional chemical catalysis
routes and not by expensive biological routes that the Polycarbonate or the
PMDI is made. Yes steel mills can create value from their CO.
Transforming
energy from one form into another always results in a net loss of energy, by
the 2nd law of thermodynamics. But the reason we transform the energy is to
convert it into a form that has a higher value for society, in a more useable
form, for reduced pollution, etc., at the expense of a loss of available
energy. There are many ways to use petroleum for example: upgrade crude
oil into gasoline, produce chemicals, run it through a combustion turbine to
make electricity, etc. But there is a reason the refining industry exists;
liquid fuels are needed.
Yes society does
need liquid fuels but we are trying to lower the overall carbon emissions and
the CO from the steel mill could be used for a higher purpose than ethanol that
winds up in an internal combustion engine that is at best 20% efficient.
The whole driver behind this “green” technology is the deployment of Capital to
make something out of the CO that is supposedly green and not wasteful.
LanzaTech
achieves a higher IRR than power because ethanol is more valuable than
wholesale electricity and because the process efficiency is higher for ethanol
production (up to 60%) than for electricity production. The efficiency of electricity
production is low (~40% and sometimes <<35 because="" combust="" dilute="" found="" gas="" gases="" in="" industrial="" inefficiently.="" low-calorific="" many="" span="" streams="" value="" very="">
OK so now you
state the thermal efficiency of the LanzaTech process as < or =
60%. If the stream is CO and there is little hydrogen two thirds of
the carbon in the CO is lost as CO2 in making the ethanol via the LanzaTech
fermentation (you did not dispute this). You agree >40% of the
heat value (energy) of the fuel is lost. Hence my original premise that
the better use of the CO to generate electricity (35% efficient) is better than
running a car on ethanol from LanzaTech that will by 0.6 time 0.2 or 12%
efficient. You can argue that the Chinese motorist wants liquid fuel but
I am simply saying more CO2 is added to the planet’s atmosphere which is the
basis of “green” analysis
Further steel
mills have little use for low grade heat and so co-gen is often not a good
option. LanzaTech is able to achieve a high process energy efficiency because
our microbe is highly tolerant to ethanol so distillation energy requirements
are quite low (<20 and="" are="" because="" by="" chillers.="" cooled="" cooling="" distilled="" energy="" ethanol="" extremely="" have="" in="" inherent="" input="" low="" of="" product="" rather="" reactors="" span="" than="" the="" towers="" which="">
OK the LanzaTech
bugs can tolerate temps that only need cooling tower cooling. Still means
27% of the energy is lost to heating the broth. Still means the
process has a water footprint. My rough guess is 4 to 5 gallons of
water for each gallon of ethanol (some water for the hydrogen and the rest from
evaporative cooling). The bugs do not take the ethanol beyond
the azeatrope with water and as you admit there is energy to purify.
It is also worth
noting that not all energy is created equal. When LanzaTech integrates into an
industrial site, we use low-value waste heat for distillation that cannot be
practically used for anything else, and therefore the energy required for
distillation drops to 0-5%. Finally, we note that the relative value of the
ethanol as a product is enhanced by logistical advantages. China and India are
experiencing rapid growth in liquid fuel demand. LanzaTech ethanol can be
transported to these markets or globally, but the infrastructure is not in
place to sell and distribute electricity from their industrial sites.
The steel mills
in China and India do generate power so I am not sure why GE can do it and
Siemens cannot.
Perhaps
Siemens should investigate what GE is doing?
3rd party
certification has shown that LanzaTech reduces CO2 emissions using actual
performance data. Ethanol produced from a steel mill waste gases through
LanzaTech’s process reduces CO2 emissions 50-70% compared to conventional
petroleum. At the same time, the CO2 footprint of conventional fuels is getting
worse with increasing unconventional fuels coming online, while the CO2
footprint of electricity production is dropping with an increasing amount of
renewable electricity coming online. These trends increase further the CO2
benefits of ethanol production over electricity production from waste gases.
Yes I do agree
that 73% of the energy in the CO is in the ethanol and perhaps in the best case
the process is 50% to 60% overall thermally efficient. I do not have
enough data to opine on the CO2 savings versus conventional gasoline and I
would have to review the third party calculations in detail to render an
opinion.
As a consequence
of the 2nd law of thermodynamics, when using CO as a feedstock, the fermenters
release some CO2 (similar to sugar fermentation). Here it is not possible to
make a more reduced product like fuels, without also generating a more oxidized
product like CO2. There is net CO2 reduction however, when compared to business
as usual, flaring or venting these gases, especially when producing a chemical
which sequesters this carbon. Further, as we react increasing amounts of H2 in
the process (found in other industrial waste gases, MSW or biomass) LanzaTech’s
reactors become CO2 consuming, in addition to the process remaining net CO2
reducing. This is a consequence of thermodynamics; the process efficiency has
not changed, just the feedstock.
OK you admit the
reaction has two thirds of the Carbon in CO becoming CO2. The steel
mill has little free hydrogen. The question I posed to Siemens was the
web link about CO2 reduction at a steel mill not a futuristic MSW or biomass
facility. If I have a large source of hydrogen why not purify
this and place in a PEM fuel cell vehicle rather than convert to ethanol and
then place ethanol in an ICE vehicle??? PEM is 60% efficient, ICE is 20%
efficient.
Lastly, steel
production is the 3rd largest stationary CO2 emitter (after electricity and
cement), and LanzaTech’s solution has received a very positive response from
this sector.
Steel produced
from scrap or DRI in an electric arc furnace is far greener than steel produced
from coke in China. The Chinese steel is the most pollutive in the
world. Of course they want some “green” thing to latch onto
From a human
health perspective, the local air quality is so problematic worldwide that it
was attributed to 7 million deaths in 2012 (WHO). This is driven by SOx, NOx
and particulate emissions. Unfortunately, combustion of waste gases into
electricity would exacerbate these emissions. By converting waste gases into
ethanol, the LanzaTech process reduces each of SOx, NOx particulate emissions
by > 90%. LanzaTech’s customers are keenly aware that the poor air quality
locally poses a threat to business in some jurisdictions, and are doubly
motivated to make a positive change using our process.
Sox
and NOx can be scrubbed. Our debate is on CO2. I thank you
for your response that was detailed and well thought out. But I
still believe Siemens should fix the web site that made the claim that: “A steel
mill that is currently using its off-gases to generate electricity could lower
its CO2 emissions by a third using the new fermentation process.”
OK if we believe GE can install power generators at 35%
efficiency (Siemens data) on CO containing off gas at a steel mill, what is
greener the power delivered to the owner of an electric scooter or the Ethanol
that will be used in an internal combustion engine on a scooter?
GE system has an overall efficiency of 35% at the generation
station. There is a loss of 10% to
transmit to a home and then a loss of 10% to place these electrons in an
electric scooter. This is an overall
efficiency of 23.85%.
The Siemens/LanzaTech ethanol system is 60% efficient (at
best per Siemens) at converting the CO to ethanol. Assuming that the supply chain in China can
get the ethanol blended into gasoline and then the fuel delivered to a service
station near the scooter owner with 98% efficiency. Then assuming the scooter operates at 20%
efficiency in converting chemical energy to kwh at the wheel. The resulting CO to wheel kwh efficiency is
11.76%. Therefore it makes absolutely no
green sense for the CO to become ethanol if it is going to propel a vehicle (in
this case a scooter). This was my point
to Siemens.
Of course if GE is greenwashing about their turbine
technology to fire power stations on CO in the off gas from a steel mill, then
Siemens is doing the right thing not to flare the gas. I can’t opine if GE is Greenwashing, but I
do believe they can generate electricity from the off gas or else I would not
have started the debate. If I owned a
dirty steel mill in China I would simply stop producing dirty steel. Of course this is not going to happen so the
market does exist to use off gas from a steel mill for some better
purpose. I just want Siemens and GE to tell us the truth. I really don’t care who
is the winner between Siemens and GE, I just want less CO2 in the air and I don’t
want to be greenwashed.
I can opine that Jim Lane gave KIOR the best thermochemical
project award and he knows zero about thermo or chemistry.
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