[Tanny]

Hello,
I looked it up online but there's no equation for it. So I wonder if there's any chemical equations for the combustion of a viable biomass fuel that can be used widely. It doesn't have to be biomass by itself but it can be the product/refined version of it.
Thanks.

[Arkcon]

Hard to know exactly what you're asking for.  You want an equation for biomass?  We don't give equation for things, only processes, we might give a formula for a compound, but biomass is often a mixture.  You may want an equation for a combustion, that's easy enough, but anything will be incomplete.

Try this:  you've done some Googling already.  Look up the definition of "biomass", and give us an example.  We'll try to give you formulas and equations.  Then, if that's incomplete, you can tell us why, and we can try to help some more.

[Tanny]

Yeah, I've been thinking of using Algae as a biomass to turn it into algae biodiesel. I'm looking to see if there's any chemical equationS for the conversion. If there are, I'll reply once again after I make sure.
Thank you for a quick reply!

[Tanny]

I've found

Oil Extraction

Expeller/Press – a tried and tested method of extraction. By letting the algae dry out and then pressed to extract the oil
Hexane Solvent Method – this makes use of a chemical hexane that can be mixed with the algae. Then using the expeller is pressed to extract the oils from the algae then it can undergo another extraction because of the hexane. Hexane are then separated through distillation. Much yield could be produce in this method. What’s more hexane is inexpensive.
Supercritical Fluid Extraction – this is the most viable way of extracting 100% oil from the algae the only downside of this process is the need for a special machinery and equipment for extraction. It liquefies the carbon dioxide under pressure and heated until that both elements are in its liquid state and gas. These liquids acts as a solvent to extract the oils from the algae’s.
Ultrasonic-assisted extraction –as the name implies it makes use of ultrasonic devices to extract oils from algae’s. In this process ultrasonic waves are being sent around the algae’s sending shock signals on to the organism as a reaction to the wave they release oil substances onto the solvent that can now be easily extracted.


2.3.2 Transesterification
 Transesterification is the process that the algae oil must go through to become
biodiesel.  It is a simple chemical reaction requiring only four steps and two chemicals.  
1. Mix methanol and sodium hydroxide creates sodium methoxide
2. Mix sodium methoxide into algae oil (Finding what it's made of)
3. Allow to settle for about 8 hours
4. Drain glycerin and filter biodiesel to 5 microns
Figure 2.5 below shows the inputs and outputs of this process.  
Figure 2.5: Inputs and outputs of transesterification reaction
The alcohol used in this reaction can be either methanol or ethanol, the catalyst is sodium
hydroxide, and the oil is any fat or vegetable oil.  The outputs are 86% Methyl Esters or
biodiesel, 9% Glycerine which can be used to make soap and other products, 1%
fertilizer, and 4% alcohol which can be recycled back through the process (Tickell,
2003).
It's a loooong loooong thing about the whole algae fuel thing.https://kb.osu.edu/dspace/bitstream/handle/1811/5981/?sequence=1
 I think this is how they turn the algae oil into biodiesel.

[Arkcon]

Good work, you've begun answering the question.  You've figured out there's no chemical formula for algae, but there is a formulation, or maybe it could be called a recipe for extracting oil from algae.  And you've found the esterfication process for making oil a better fuel for a diesel engine.  We've discussed that last step many times on this forum, you should search for that here and you'd learn some of the ideas and challenges.  Good wok on your part, so have one one me.

[fledarmus]

This isn't exactly a biomass process - what you are actually doing is extracting one family of  chemical components (the triglycerides) from the enormous number of chemical compounds (proteins, amino acids, nucleic acids, steroids, starches, carbohydrates, etc.) that make up a cell. Those triglycerides can then be saponified and the fatty acids esterified to generate biodiesel.

One example of a triglyceride:

[Tanny]

So, the oil is basically a triglyceride. I see there's apparently different formulas for different oil source. So I try to find the one specific for the algae?

[Tanny]

Can I know how to find the spontaneity of these processes?
2CH3(CH2)7CH=CH(CH2)7COOH + 51O2 --> 36CO2 + 34H2O
Also, it the above right for the combustion of the methyl esters?

[vmelkon]

Spontaneity?

From what I have seen with the production of biodiesel from vegetable oil, they mix the reagents and they let it react for a few hours under heat (50 C). I assume the 50 C is because they want to stay under the boiling point of methanol.
As for the methanol and NaOH mixture, I posted a topic about it and whether it is true that sodium methoxide and water forms. The person who replied said that it probably form sodium methoxide and water but it is in equilibrium with methanol and NaOH. In other words, there is always some methanol, so it is best to stay under the bp of methanol (64 C).

[Tanny]

Is it possible to calculate and show the work of the enthalpy of the reaction, entropy of the reaction, the work of the system(W=P∆V), the change in internal energy, Gibbs free energy for the below equation without knowing the akyl groups that are represented by the R on the bottom?

And that of
 Diesel fuel molecule represented as C16H34
• Chemically correct air-fuel ratio assumes all fuel burnt to CO2and H2O
• C16H34+ 24.5O2+ 92N2　ーー＞92N2+ 16CO2+ 17H2O
Chemically correct air to fuel ratio:  14.9: 1
Chemically correct air to fuel ratio:  12.5: 1
?

[Arkcon]

You could just pick one alkyl group, and say "assuming R = this alkly group" results are ... to begin the calculations.  You can look up what type of alkyl groups are common in diesel and just use those in your calculations.  Or you can look for representative R groups, the most common found in petroleum-based diesel and found in algal oils.  Some people use algal oils as nutritional supplements, so you may be able to find lipid distributions of algal oil online.

[Tanny]

Calculate and show the work of the enthalpy of the reaction, entropy of the reaction, the work of the system(W=P∆V), the change in internal energy, Gibbs free energy for
The Combustion of C19H36O2?
How do I find a complete equation for this? I know it reacts with O2 but that's all. I don't know the delta H, the delta S for C19H36O2.

[Tanny]

Nvm, I managed to figure it out. I'm trying to find delta H with bond enthalpy now. Could someone help me expand this structure further? What happens between the COO(CH2)15. Is it CO-O(CH2)15? What happens inside CH2 and what happens between CH2 ions? Do we represent something as single bonds or ??

[UG]

What happens between the COO(CH2)15. Is it CO-O(CH2)15? What happens inside CH2 and what happens between CH2 ions? Do we represent something as single bonds or ??

See if this helps.

-----------
Edit, some of the lines don't appear to show very well on my computer, but they are all single bonds except the C=O bond.