Biofuels, Not Food for Fuel (Part 2)

Puerto Rico has a severe used tire problem. At some point Puerto Rico became the point where the excess tires of other states ended being stored. This was given our lack of vision of establishing a tire recycling program. Currently the practice of recycling in Puerto Rico is reduced to storing recyclable materials until a fire or environmental incident burns the material down. This bad press has killed any attempt to reuse tires as an energy source.

A couple of days ago I wrote the first part of this series on Biofuels. For those that have not read the original article it is included here:

http://alcantarillaalquimica.blogspot.com/2009/12/biofuels-not-food-for-fuel.html

On that article I summarized that Puerto Rico has a large amount of raw materials that can be used to generate biofuels or used as an energy source in PREPA power plants or other large kilns and furnaces available on the Island. Cemex tried this approach in Ponce and failed, given the opposition of 'environmentalists' that prefer the threat of a large scale fire, or a mosquito outbreak that is the typical fate of the tires in Puerto Rico. I stated several sources that could be used. Today I have decided to focus in used tires.

Why tires? Because I am reminded of the problem every day whenever I pass Comerio Avenue and see buildings filled with recapped or damaged tires waiting to be transported to a storage area where they are eventually burned 'accidentally'. Plus a whole recycling program was supposedly established to manage this issue and all it has left us is with more charges when we buy tires or oil for our cars. Tires fill our landfills.

So two things are needed to deviate tires from landfills. One is taking them out of the regular trash, as required by the recycling laws already written and the other implies shredding or reducing the size of the tire to be managed more effectively. Both require machinery.
The following excerpt is from american recycler:

http://www.americanrecycler.com/1007/spotlight.shtml

Of the 290 million scrap tires generated in the United States annually, more than 80 percent are reused or recycled for sale into various markets. That’s up from just 17 percent in 1990. The biggest markets for scrap tires generally require shredding as part of the process and that’s turned into a good business for tire shredder manufacturers.also:
Overall, the future remains bright for shredder manufacturers and the customers they serve. As SSI’s Fleming says, “Scrap tires will continue to be a disposal problem, populations will continue to grow and consume more raw and recycled materials, and used tires will increasingly be needed in order to make longer-lasting new products as well as synthetic fuels and other valuable materials.”

So before even entering into using tires as a fuel or biofuel source they have a useful purpose by simply shredding them. Now that is interesting. It is something we should have been considering a long time in Puerto Rico but we still do not believe. For instance, I got interested on rubber mulch a few months ago when I saw these bags of rubber mulch in Sams Club at Bayamon. Bought 10 sacks because the product convinced me. It did not make the ground I wanted to cover impervious to water, as would have happened with concrete, but it would not rot and float away as that cheap imported pine mulch chips do.

Their product got me interested and I have included a picture and a link to their website. It is a nice idea that should be checked more often by municipal landscape designers as seen on the picture below.

http://www.perfectrubbermulch.com/

If not as a mulch, smaller machines can be used to cut the tires to make bumpers, mats or other items...This one is a good idea for our economically challenged times.

http://www.recycledtiremats.com/recycled_tires.htm

However the operation of managing used tires is not as simple as it seems initially. It requires a huge capital investment and should be left to a properly planned and well designed central facility. For instance here are recommendations from one potential supplier of machinery of those seen during the research of tire recycling equipment:

http://www.americanrecycler.com/06spotlight02.html

Now, this only solves part of the problem. Fortunately there are other uses are available for the material shredded. It could be used to control excessive erosion of our public landfills or to control the nasty leachates produced from landfill runoff. This still does not require burning or converting the tires in fuel.

Preliminar studies indicate the leachate from tires is not toxic since below toxicity levels

http://www.ecst.csuchico.edu/~dxcheng/CE_Application_Resources/lechate%20from%20scrap%20tires.pdf

Example of uses to control landfill leachate...

http://www.p2pays.org/ref/15/14315.pdf
http://www.ciwmb.ca.gov/Publications/Tires/21299005.doc
http://www.faqs.org/abstracts/Environmental-services-industry/Using-tire-chips-to-control-landfill-leachate-Festival-seeks-independence-from-landfill.html

However, care must be taken on the disposal method of the used tires. The leachate removed chemicals are entrapped with the rubber in the tires, the metal in the tires remains. If burned or used as fuel these concentrations need to be studied further to not cause a larger environmental problem. This should not be an issue on residential or institutional use.

Summarizing this already technically complex article: Tires should be managed more efficiently than our current practice. Municipalities can benefit from mulching tires for landscaping.

On the end, if all these efforts fail the shredded tires can be used to generate fuel by direct burning on a kiln or power plant boiler. It can also be used to generate syngas and other biofuels. Some links on this below:

http://wasteage.com/mag/waste_wasteenergy_power_plants/
Burning increases the metal levels on the total ash but air emissions can be managed by pollution control equipment. It just requires more monitoring on the ash quality disposed of.
http://jeq.scijournals.org/cgi/content/full/31/5/1484
http://jeq.scijournals.org/cgi/reprint/31/5/1484.pdf

Or it can even be used to produced activated carbon for many industrial applications, including the removal of trihalomethanes on potable water.

http://digital.csic.es/bitstream/10261/18420/1/S01_7.pdf

http://www.p2pays.org/ref/11/10504/html/biblio/htmls/pyh1.htmInfo from [http://pubs.acs.org/doi/abs/10.1021/ie00048a023]

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waste recycling tires biofuel environment rubber mulch

Biofuels Not Food for Fuel

On a recent article the nature of Biofuels came into question. All this green revolution calls for hybrid cars, wind, recycling yet the United States goverment looks at Ethanol as a major source of energy. Instead of using traditional waste products like decomposed fruits and produce, or spent sugar cane waste (bagazo) to generate the fuel it is being lobbied to use corn and sugar beets from the mainland's foodbelt. Food for Power, which is a stupid way to go.

This discussion inspired Antigonum Cajan's article

http://endemismotrasnochado.blogspot.com/2009/12/are-you-into-biofools-dream-or-hybrid.html

for which I made the following comment:

biofuels are plain wrong when food is used to offset the carbon dioxide
emissions. the largest options to generate biogas, biodiesel,etc. are on the aaa
sewage plants and on agricultural waste. both can benefit from a centralized
waste treatment center using anaerobic treatment to generate methane while
eliminating a lot of waste to the landfill, and even beneficial byproducts such
as compost or mulch. hell, even the option of shredding and using tires as fuel
was ignored by 'environmentalists'. the tire problem is still there. not all
biofuels are created equal.

http://alcantarillaalquimica.blogspot.com/2009/12/necesitamos-empezar-reusar-agua.html

Antigonum Cajan's remark regarding biofuels is accurate. My point was very rushed, tried to cover too many bases at once. My point was -Not all biofuels are created equal-. If we truly want to harvest energy sources and go green, we need to find sources that are currently a waste. If not, the whole point of reuse is lost. Also, if one is to obtain energy the net production must be positive. If it takes more energy or cost to generate the energy sent to the grid then we are actually spending more energy than we did before. What is the point of recycle then? We ended worse than before.

[image from http://www.propal.com.co/propal/images/PropalProcesoBagazo.jpg]

Way before this language of green buildings, LEED certifications, sustainability or even the Reduce Reuse and Recycle campaigns engineers, especially chemical engineers, were experts on what we knew as Loss Prevention. We did (and still do) a holistic analysis of a process and look at every feed stream, at every waste stream and every source of emission. A material balance, if I get 100 pounds in, I have to get 100 lbs out. All waste needs to be accounted for, either as a waste or as a potential product that can be recovered and reused. Waste is to be minimized. At least that was our original aspiration.

The approach used to push inefficient ethanol against other technologies is the effort of a large lobbying effort in Capitol Hill. Many have denounced this fiasco, as presented in this article from Rolling Stone of about 2 years ago (http://www.rollingstone.com/politics/story/15635751/the_ethanol_scam_one_of_americas_biggest_political_boondoggles)

From a technical standpoint corn ethanol is not a non viable ptocess. The problem is that to generate the fuel you spend energy at a ratio 1.3 to 1 for corn ethanol against a 5 to 1 ratio for gasoline. Plus the ethanol mixtures have a much lower heating value than that of other fuels. Therefore this is not a cost effective way of solving the energy crisis.

Therefore the potential is to use waste products to generate this energy. What problems does Puerto Rico currently have:

(a) Overloaded Landfills

(b) Inefficient Wastewater Plants with Deficient Solids Management

(c) Large farms with chicken, pig and horse manure

(d) Large amounts of vegetation that ends up in the landfill after pruning

(e) Surplus feeds of food wastes or decomissioned food (whatever happened to Pan American Grain's bug infested rice)

(f) Enormous amounts of damaged tires

These are the streams that need to be used to generate any power. Given the proper air pollution control devices and management of liquid and solid byproducts the wastes can be used to generate power to the electrical grid and any waste generated can be made into useful byproducts such as mulch, asphalt or concrete aggregates or sawdust.

There are many ways to achieve this (and will be discussed on further articles at the Alcantarilla), what we need is to have public officials with the interest of creating proper public policy. We also need to have proper 'environmentalists' that look realistically at any project comparing benefits and environmental impact. Not all progress is bad. You cannot just prohibit any type of construction at the expense of not constructing anything at all.

It is really an educational process for all involved. Puerto Rico is full of motivated professionals focusing on the ethical and correct approach to sustainability. The problem resides on two extremes: environmental activists that are really blocking the progress in Puerto Rico based on a political agenda who really give a hoot about the environment and the other extreme where those in charge of prociding assesment to our public policy officials only see the green reaching their pockets. If Puerto Rico is to go forward these two extremes need to disappear.

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ethanol biofuel waste environment