3 replies to this topic

[peaston]

Hi there, I have been tasked with producing a report on bioethanol production from lignocellulosic materials, organic waste being the main area of interest. I have also been told to find suitable kinetic data to create a preliminary reactor design.

The report so far has consisted of some background into past and previous methods of bioethanol production using 1st generation methods, i.e., sugar cane bioethanol production in Brazil and production from corn starch in the united states. having accessed the methods for preparing it in this way and noting the conflicts arising from it, such as land grabbing, population rise and the fact that we should not be using food resources for fuel.

From that, I found out means of acquiring lingocellulosic materials form organic waste, Municipal solid wastes, specifically paper and agricultural wastes have proven to be of significant interest, and I have analysed the techniques implored to produce ethanol from these materials.

The final part is for me to perform a reactor design based on the kinetic data available, but i am having trouble acquiring suitable sources. Is there anyone who can suggest particular textbooks or journals whereby i could get this data?

Any help would be appreciated, many thanks in advance!

Andrew

[markymaark]

You say you are looking for kinetic data but did not say which method of production you are looking for.

Are you breaking down the lignocellulose via enzymes or High P, T acid addition or..

Given this is a very valuable and current operation, I doubt you will find any real kinetic data. They are most likely under lock-and-key. Also, there are dozens of reactions and side-reactions with valuable by-products.

[peaston]

Hi thanks for your reply.

The method i was most interest in was biological pretreatment hydrolysis of waste paper. waste paper being a cellulosic material seemed good to use as it would decrease landfill and its inexpensive and regularly available.

biological pretreatments as well seem like a good method to use as they are also cheap and do not produce any toxic materials either.

the steps i thought that seemed relevant are as follows:


Waste paper -> mechanical pretreatment -> biological hydrolysis and fermentation - > distillation -> ethanol

so obviously i need to determine the optimum size for the mechanical pretreatment to break the paper down into, and then design a subsequent environment for the hydrolysis to take place.

hope this helps

[markymaark]

You are correct.
A colleague had developed a process for the wastewater from paper mills.in a cellulosic conversion reaction

Some key information in your feedstock should be:
1) The % of cellulose, hemicellulose etc since this will be the determination of your yield
2) The % water. Don't overlook this. You will be performing a distillation and the more water, then that's more energy you need to input to seperate your ethanol.


Breaking the feedstock down by a mechanical pretreatment should:
1) Allow you to pump
2) Increase surface area for your hydrolisis/fermentation steps
The emphasis is on point 1.

As far as the fermentation goes, should be simple depending on the organism you're using. Just maintaining pH, O2, mixing, Temperature and dextrose like any other fermentation.

I've also seen Settlers used after the mechanical pretreatment step you speak of. This is due to bouyant peices will not have contact with the correct conditions in the fermenter and will cause problems throughout the process.

Some thoughts.

Mark