It is good to maximize yield, but I was my understanding that the bagasse was burnt to power the mill, if they use the bagasse then what they are going to power the mill with?

An expert could say, but, presuming the bagasse is not 100% cellulose, after it's conversion to sugar, there should be a non-cellulose remainder that could be burnt.

>> what they are going to power the mill with? <<

This is probably one of those things where it depends no the economics of things, is it more profitable to convert the bagasse to ethanol or use it to power the processing of the sugar cane (probably versus some dirty cheap option...my sarcastic side speaking there).

True, Ben. However, the point is to convert as much of the biomass to liquid fuels and then use energy from wind or solar as necessary for production of this bio-fuel. Plus it is most likely more economical to convert bagasse to ethanol rather than converting it into electricity and heat. After all the price of oil keep rising and so will the possible selling price of ethanol.

I agree with maximizing conversion efficency, and I hope that any energy inputs needed for the process be from renewable stocks but I worry that they are just burning something else to power the mills.

I just looked it up. Almost all electricity in brazil is from renewables 83% from hydropower. http://en.wikipedia.org/wiki/Energy_policy_of_Brazil#Electricity . Plus they are in the process of installing a lot of new wind power. http://en.wikipedia.org/wiki/Wind_power_in_Brazil

So it is truly a good idea to convert bagasse to ethanol in Brazil.

Well then thats better. I wasn't saying it was a bad idea to convert bagasse only that it should not be replace with fossil fuel input.

Now I just read another source where the CEO and president of Novozymes Steen Riisgaard say that the deal with Brazil has the potential to increase by no less than 100% the ethanol yield without increasing the area used to grow sugar. This deal is a big thing in Denmark and the Brazilian President is currently visiting Denmark so this is why it is announced today.

Source (in Danish): http://epn.dk/industri/medicinal/article1087011.ece

I don't know how that possibe as bagasse only repersents 30% of the sugar cane plant mass.

Very good point Ben. The idea is to start with enzymes for bagasse and then move on with enzymes for the other biomass components. Novozymes is excited about this development because the current production method in Brazil hardly uses any enzymes unlike the US production of ethanol that uses lots of enzymes.

I was surprised that there was not more comments on the 6 Sept. (Greencarcongress) Mitsui announcement about a fourfold increase in ethanol production that was possible with thier new enzymes. I was hoping one of you chemists on this site could tell me if that was possible.

JIM,

I would love to, but I can't find the article, mind linking it?

If they can do this, Brazil could really increase their ethanol production without using more land. The lignin left over could power the plant or be gasified to synthesis even more fuel. Use solar thermal for the distillation and you are greener still. (no pun :)

Ben Page down this site and the entry will be the first(last) entry for Sept 6th titled "Mitsui Engiineering Tech. Increases Bio ethanaol Output Fourfold"

Jim,

Well I could not find it on the main page but using the name you gave me it came up in the search. The claim is presented with little explanation, with the right feedstock a 4x increase in performance is theoretically possible, for example a +100x improvement might be expect for yeast modified to metabolize cellulose (as yeast can't metabolize cellulose at all) but a 4x increase say using glucose as the feedstock is impossible as the yeast is already optimize to us it a efficiently as possible

but a 4x increase say using glucose as the feedstock is impossible as the yeast is already optimize to us it a efficiently as possible

However, alternative pathways (not used by yeast) could make ethanol production from sugar more efficient, in the sense that more of the carbon ends up in ethanol rather than the CO2 side stream. For example, conversion of glucose to acetic acid, followed by hydrogenation of the acetic acid to ethanol. You'd need a hydrogen source for the last part, though.

The efficency is pretty well set: C6H12O6 -> 2C2H5OH + 2CO2, anything better would not produce ethanol (such as C6H12O6 -> 3CH4 + 3CO2) or would break thermodynamics and not produce energy for the cells killing them. Or like you said you would need a outside hydrogen source and thus anotehr energy input.

//It is good to maximize yield, but I was my understanding that the bagasse was burnt to power the mill, if they use the bagasse then what they are going to power the mill with?//

See, bagasse is so abundant that mills produce excess power and electricity. They nowadays feed this into the local grid. But this requires infrastructures and limits possible locations for plants.

If you turn the excess into cellulosic ethanol, this problem is solved. You can still power your mill with bagasse, and turn the rest into liquid biofuel.

It's also a simple matter of economics: liquid fuels happen to have a higher value than green electricity.

Gio,

I agreed with all that, my only concern was that the energy input would not be replace with a fossil fuel.

Dr. Pazner has answered the bagasse question years ago.
We just needed the right technology to take advantage of it. Read the body text below. There is more sugar in bagasse than is recovered from the raw cane. It is not 6 carbon sugar however.

Fw: [BIOENERGY] Promocion of bioenergy
lazslo lpaszner at SHAW.CA
Sun Apr 25 22:03:50 EDT 2004

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----- Original Message -----
From: lazslo
To: MMBTUPR at aol.com
Cc: BIOENERGY at LISTSERV.REPP.CA
Sent: Saturday, April 24, 2004 8:41 PM
Subject: Re: [BIOENERGY] Promocion of bioenergy

Dear Mr. Smith,

Sugarcane, where it can be grown, is one of the highest yielding biomass producer. Yields range from 15 dry ton/ha to as high as 35 dry ton/ha (45 wet T/acre to 90 wet T/acre). Another 25 to 30 % biomass can also be recovered if the leaves and tops are also harvested. In most countries the leaves and tops (trash) are either burned in the fiueld or left in the fields, as it interfers with sucrose extraction.

Further, sugarcane also has the advantage that its moisture (juice) also contains a fair amount (8 to 16 %) sucrose, while the dry bagasse (about 28 % of the wet weight of sugarcane with 50-60 % moisture content) is lignocellulosic, i.e., consists of fermentable (reducing) sugars: 72 %, lignin: 19 % and extractives: 7 % (among others like wax).

At 12 % sucrose content it takes 8.33 T wet sugarcane to make 1 T of sucrose sugar. At a fermentation ethanol yield of 0.46 g ethanol/g sucrose, it takes 2.17 T sucrose to make one ton of ethanol. Therefore, the total wet sugarcane required to make one ton of ethanol is 18.12 T. The bagasse yield, therefore, is 5.07 dry T per ton of ethanol made from sucrose. If 48 % out of the 72 % of the bagasse sugars which ferment to ethanol (not all reducing sugars in bagasse ferment to ethanol with baker's yeast: Saccharomyces cerevisiae) the 5.07 dry T bagasse will yield 2.43 T fermentable sugars which at 0.478 g ethanol/g glucose will produce 1.16 T ethanol, i.e., 0.16 T more than obtained from the associated sucrose.

The co-product of sucrose fermentation to ethanol (a.k.a. Brazilian style) is energy. If the bagasse is dried to 12-15 % moisture content, it will yield about 475 kWh electricity per dry ton. At 5.2 Cents/kWh, the total value recovery from the 5.07 dry T of bagasse is $ 125.23. The current retail value of 1.16 T ethanol is $ 617.16!

But, since we have decomposed the bagasse to its chemical components (one of the easiest decomposable lignocellulose species), the 24 % xylose (1.22 T from 5.07 T bagasse) when converted to xylitol (about 1 T is recovered) has a street value of $ 8 000/T at 98 % purity).

The lignin yield will be 963 kg when converted to Ca-lignosulphonate (sucrose-free) and is worth $ 433 in 45 % solids solution or $ 819 in spray-dried powder form.

The wax (about 2% or 10.1 kg) is worth $200.

Therefore, the total chemical value recoverable from 5.07 T bagasse is $ 9 250 or $ 1 825/dry T! This compares to its fuel (energy) value of $ 24.7 /dry T. Therefore, burning the bagasse to generate heat or electricity is not a good option and should be stopped.

The technology which can dissolve the wood is known as ACOS Biomass Ethanol Refining. It is true that the capital cost of this technology is high, but so is wet milling of corn. According to the above revenue calculation it is evident that the ethanol value is only 10-15 % of the total revenue, nonetheless, this provides for production of a credit-rated ethanol for 12 to 17 cents/L, without any government subsidy. Further more, the ACOS process is economically viable (profitable) down to 50 dry T/day capacity. (Compare to two-stage dilute acid at 1 500 T/day and enzyme hydrolysis at 2 000 T/day minimum break-even capacities.) The ACOS process will return a fully depreciated and tax paid (40%) ROI of 45-50 % at 350 dry T/day feedstock capacity. The ethanol yield from dry bagasse is 310 L/ dry ton.

With rapidly falling sugar markets (and prices), more and more sugarcane juice will be converted to ethanol. It is high time that bagasse conversion to bioethanol be included in the sugarcane conversion to energy. The future of the sugarcane ethanol industry is in the bagasse not the cane juice! This would take us a giant step closer to switching to renewable energy from fossil fuels since ethanol will eventually develop into a global, tradable fuel commodity, where demands of industrialized countries can be supplied with ethanol from surplus made in developing countries.

While the world ethanol production is now around 23 billion L/yr, if all the world-wide projections are realized we could easily reach 40 billion L/yr by 2008. The increase in production will not be from corn or juice - it will be from the bagasse. The sugarcane juice is expected to play a "higher order" role in the future.

Regards,

Laszlo Paszner
PASZNER TECHNOLOGIES INC.
2683 Parkway Drive
SURREY, B.C.
CANADA, V4P 1C2
Tel: 604 538 1349
Fax: 604 538 6108
----- Original Message -----
From: MMBTUPR at aol.com
To: lpaszner at SHAW.CA ; BIOENERGY at LISTSERV.REPP.ORG
Sent: Saturday, April 24, 2004 5:11 PM
Subject: Re: [BIOENERGY] Promocion of bioenergy

to Bioenergy List from Lewis L. Smith

Ref. Laszlo Paszner's comments of 24 April on a posting by Kevin Chisholm.

Cane is widely [and excessively] grown for sugar throughout the world, but cane's natural tendency is to produce fiber, not sugar. In fact, in 1977-81, Dr. Alex G. Alexander established in Lajas, Puerto Rico, in 1977-81, that it is economically and technically feasible to grow cane for energy. At the time, our idea was to burn the bagasse in a traditional pile-burning cane boiler, but to generate steam at 850 psig, instead of the traditional 150-200 psig. This was because no commercially proven technique existed for decomposing the bagasse into its major components —
cellulose, hemi-cellulose and lignin. Now such a process exists.

The first pass in cane milling is chop up the cane stalks, then wet and squeeze them, as if one were cleaning a mop. This produces two intermediate products, cane juice [which contains most of the sugars] and bagasse, a moist fiber. The conversion of sugars to ethanol is routine. Once the bagasse is decomposed, a large number of commercially proven techniques exist for converting the three main components into commercially useful products, among them ethanol !

I would not build a new cane mill to do this, but the conversion of existing cane mills to multi-product output as described above, is probably very attractive in a large number of countries. This would get us off to a good start with biomass energy, without making a lot of crop substitutions or opening virgin or underutilized land.

Cordially.

Just a few questions:

Could edible sugar be extrated first and all or most of the rest (of the sugar cane) be converted into liquid fuels?

As for the processing energy required, it seems that total hydro power potential is only about 50% developed in Brazil, would the other 50% be sufficient for an extended period?

What will happen to the land productivity after 10 or 20 sugar cane crops?

Can agricultural feedstock sustain high level liquid fuel production for an extended period without adversely affecting essential food production?

John Schreiber,

I minor problem with lazslo statements is the production of side products from bagasse: these products though of high value have limited markets, if every cane-to-ethanol mill produces those side products they would quickly saturate these markets and the price of the products would drop to below profitable levels. Converting bagasse into ethanol is more advantageous as the ethanol market is far less limited, even so the more products that can be made from biomass the more competitive the biofuels market will become.

When Fisher-Tropsh synthesis installations will be easily implemented, much better conversion rates will be reached. Also, it will be rather easy to produce optimal combustion fuels.
If (green) hydrogen is added to the process, every carbon atom of the biomass can be converted to optimal fuels.

hi .. tis is abt bioethanol

hi .. tis is abt bioethanol