While I am
mildly embarrassed to be a regular user of K-Cups, I am not embarrassed about
the fact that our company, like many, pays extra to ensure our K-Cups aren’t
thrown in the trash. Rather we collect them in a special bin and they are
shipped to the Lafarge Cement Plant in Kamloops where they are used as an
alternative fuel source. For those of you unfamiliar with cement plants, they
are ubiquitous, energy-hungry and a tremendous source of greenhouse gas emissions.
They are ubiquitous because everywhere you go in our modern society we have a need
for cement since it is the primary ingredient in concrete and each plant is
limited in the volume it can produce. The production of cement is a very energy-intensive
activity as the lime kiln needs to be heated up to 1400 oC and held
there for a long period of time since the calcium carbonate (read limestone
rock) needs to reach a temperature over 900 oC in order for the
chemical reaction necessary to produce quicklime to occur. What most people don’t
realize, though, is how this energy-intensity reflects in carbon dioxide
emissions. As an Earth Institute report (ref)
details:
Producing a ton of
cement requires 4.7 million BTU of energy, equivalent to about 400 pounds of
coal, and generates nearly a ton of CO2. Given its high emissions
and critical importance to society, cement is an obvious place to look to
reduce greenhouse gas emissions
The cement
industry has managed to keep its head down in the climate change debate but as
noted in the Earth Institute report, as an industry it represents 5% of global
carbon dioxide emissions and has been growing at a rate of 2.5% annually. That
is not to say the industry is not trying, indeed they are (ref).
The issue they face is that about half of the carbon dioxide emissions
associated with the cement industry are based on the chemical processes
involved (calcium carbonate is converted to qiuicklime with the release of a
carbon dioxide molecule); these chemical-based emissions cannot be eliminated.
Instead the industry has to concentrate on the other half of their emissions,
the greatest part being associated with the fuel being burned to generate the
heat. So one of the big goals of the cement industry is to move away from
combustion fuels like coal or natural gas towards renewable fuels like wood
waste or...you guessed it K-Pods. Ironically enough K-Pods make up a very
reasonable source of combustible material for a cement kiln. They are made of
hydrocarbons (which burn) and the excess coffee grounds don’t really hurt as
they actually serve as useful biomass. So
here we have an industry that is producing a waste stream (K-Cups) that would
otherwise clog up our waste chains and fill up our landfills and we have a
second industry looking for an alternative fuel source. What we have is a good,
but imperfect, solution to an otherwise intractable environmental problem. You
see, K-Cups aren’t going anywhere until public perception makes it impossible for
environmentally aware companies and individuals to use them; and even then they
will not disappear completely as they are (as described by the creator) like a cigarette
for coffee. Moreover, our society cannot operate without cement. As described
in the Earth Institute report concrete is the second most consumed substance on
earth after water.
One of the
big fears expressed with burning plastics in cement kilns involve the off-gases
from the combustion. What most people don’t recognize is that the heat and
retention time needed to heat solid rock to over 900 oC is also
ideal for breaking down fuel sources to their base components with few or no
nasty by-products. You see the reason most engines give off nasty gases is that
they do not get hot enough, long enough to get complete combustion of the fuel.
Instead, in most auto or diesel engine, they get partial combustion and all sorts
of interesting and distressing combustion byproducts are produced. In a cement
kiln the combustion is contained to prevent loss of heat. This results in as
close to an ideal combustion chamber as we will see in modern industry. These near-ideal
combustion chambers were actually tested for use in eliminating PCBs and other
hazardous wastes in the 1980’s and 1990’s and were determined to combust the
compounds with essentially 100% efficiency (ref). The main reason
the plants were not turned into giant hazardous waste disposal facilities had
to do with optics and politics rather than the actual chemistry involved in the
processes.
Ironically,
using renewable energy sources like PCBs, K-Cups and used tires in the
combustion process can actually reduce the negative emissions from the kilns.
One of the historic issues with these kilns has been the release of gaseous mercury
from the combustion. As many of you know, amongst their many downsides, all
coals contain some mercury, with concentrations in US coals ranging from 0.08
μg g for coal in the San Juan and Uinta regions to 0.22 μg g−for the Gulf Coast
lignites (ref).
Mercury, unlike the coal, does not burn, so by replacing coal with renewables we
actually see a reduction of mercury emissions from the cement kilns (ref).
The
inspiration for today’s post was a news story I watched last night on my local
television station (ref).
It was all about the effort by Lafarge Canada
to use K-Cups in their Kamloops cement plant. As I write above, while not the
perfect answer it is the best, imperfect solution to an otherwise intractable environmental
problem. At the end of the story the reporter interviewed a local environmental
leader who tried to throw cold water on the project. He said (pardon my poor
transcription):
In this case when you talking about, you know,
burning plastic instead of coal it is perhaps a tiny little step in the right
direction but it comes with a lot of consequences....It is not the kind of
stuff you want in the atmosphere
It was clear
from this answer that the environmental leader had no idea how a cement kiln
works and rather than saying “I don’t know
enough about this to comment, let me look into it and get back to you” he
spouted off a negative answer. This hubris amongst the leaders of the
environmental movement is one of the things that really turns me against the
movement. One of the most important things I was taught in graduate school was
the ability to admit “I don’t know” rather than trying to bluff my way through
problems. Once you learn to say “I don’t know” you can learn much more quickly
and oddly enough, it adds tremendously to your personal credibility. People
will feel comfortable coming to you when they know that you will not set them
on the wrong course rather than admit to not being fully informed. The funny
thing is that given the size and complexity of the environmental field, much of
the time any one individual will not have the skills needed to accomplish a
task. In our office we have civil, chemical and mechanical engineers, we have a
chemist, a couple biologists, a toxicologist, a couple geographers, a couple
geologists and a hydrogeological specialist. Even with all this in-house
expertise we are willing to bring in outside help when the need arises. This is
because we have all learned the importance of recognizing our own limitations
and the perils of hubris. To maintain this culture we all have been told again-and-again
stories of failures based on hubris until they were drilled into our heads. We
are told stories of other companies drilling without proper daylighting and
hitting tanks or utility lines, stories of consultants who tried to do it all
and failed in one spectacular fashion or another because someone was not
willing to admit when they needed help. We emphasize this to remind ourselves that no
one is all-knowing or competent in all things. The problem with the
environmental movement of today is that instead of recognizing their limitations
these folks wander around in a Dunning-Kruger haze and instead of making us
trust them we become less and less trusting in their knowledge or expertise.
When a Council of Canadians handout tells me that benzene is a polycyclic
aromatic hydrocarbon (ref)
I start to wonder what else they may be saying that is completely wrong. When
an environmental group trumpets a “cancer
cluster” that is ultimately proved to be no
such thing I know not to trust them the next time. When an environmental
leader goes on television and dumps on a win-win attempt to reduce waste going
into our landfills while reducing greenhouse gas and mercury emissions from a
necessary industry then I begin to wonder how anyone can trust these people on
other big issues.
In high-school, like many of my peers, I read Shakespeare’s
Macbeth and learned early on that hubris is a great failing. In university, and
my current occupation, I have been taught that hubris can be controlled by the
simple action of admitting that I don’t know everything and recognizing that sometimes
I need technical help. Until the leaders of the environmental movement learn
this truth they will continue to trip over their own feet, delaying good
projects because those projects may not be perfect and slowing environmental improvements
because they are unwilling to admit that they aren’t all-knowing.
Excellent post. I wonder if the cement plants can't be modified to use enriched air and capture the CO2
ReplyDeleteThere are efforts to move towards carbon capture technologies but these are still in their infancy.
ReplyDelete