I'm currently in Sao Paulo, Brazil attending the 1st Brazil-US Biofuels Short Course organized by Fulbright Brazil. This post was originally posted at www.davidwogan.us.
Today we visited the Iracema Sugar Cane Mill, which is a few hours northwest of Sao Paulo. The mill takes sugar cane stalks from nearby plantations and refines it into sugar and ethanol. All of the sugar mills in Brazil make sugar and choose whether or not to make ethanol based on market prices. I have never been to a sugar mill or ethanol refinery today.
While sugar and ethanol are the main products from the mill, leftover biomass, or bagasse, is burned to create process steam and electricity that powers the plant. All ethanol plants are required to be self-sustaining or else they're products are hit with a penalty. The flue gas from combusting the bagasse is scrubbed with water vapor to remove (most) particulate matter.
The exhaust is mostly water vapor.
They produce a lot of bagasse.
The scrubber system.
While most of the sugar cane is harvested mechanically a fair amount is still burned and delivered to the mill. Today's cane was milled. Notice the burn marks and full stalks. Mechanically harvested cane is shorter because it is chopped up into smaller pieces by the harvester in the field.
The cane stalks are milled by giant machines.
Juices from the cane goes off for processing while the bagasse is separated out.
The sugary juices are hit with steam and then left to turn into molasses. The solid sugar crystals are then removed from the molasses by a centrifuge. The remaining sugary liquid is sent off to be fermented and distilled into ethanol.
The sugar crystals are stored in a giant mountain of sugar bags.
We didn't get to walk through the refinery, but we did get to travel out into the fields and see the harvesting.
What a sight it must have been to see a bus full of Americans get out and take pictures of cane harvesting then get back in and leave.
The sugar cane is several meters tall!
We watched them dump cut cane into trucks.
We made sure not to get run over by the big machines.
The trip to the sugar cane mill was very educational. Before going I had a hard time visualizing the scale of biofuels production, but I have a better understanding about it now. Even though I'm not a huge fan of ethanol, you have to hand it to the Brazilians for having a large-scale system that is very efficient.