Twin Screws for Getting Energy From Tequila.

[NNadir]

Catching up on my reading, I came across this paper: An Experimental and Modeling Study on the Pretreatment and Alkaline Hydrolysis of Blue Agave Bagasse in Twin-Screw Extruders (Juan Carlos Morales-Huerta, Oscar Hernández-Meléndez, Martín Guillermo Hernández-Luna, Octavio Manero, Eduardo Bárzana, and Eduardo Vivaldo-Lima Industrial & Engineering Chemistry Research 2021 60 (34), 12449-12460).

Blue Agave is of course, the source plant for making tequila.

Between 1973 and 2020, I managed to avoid vomiting, a subject of some amusement to my sons because I confessed that the 1973 incident involved 25 cent tequila sunrises in Ensenada, Mexico, at which time I threw up in my souvenir sombrero hat. My sons love that story of my stupid life when I was their age. (They are far more serious and accomplished than I was back then.)

I don't know, thinking about this paper, particularly since it involves twin screws just struck me as funny. I sure was screwed in Ensenada when I was sick from being stinking drunk.

It's a serious paper however, about chemical engineering technology, and the goal of the paper is to obtain materials and fuels from waste blue agave after the recovery of the fermentable liquids from the blue agave plant. Apparently there's a lot of it in Mexico.

From the text:

Lignocellulosic biomasses, composed of mostly lignin, cellulose, and hemicelluloses, have been used as raw materials to produce added-value chemicals, either sugars on its own (e.g., xyloses, glucoses, and arabinoses), or compounds derived from the sugars or from the biopolymers themselves (e.g., grafted polymers).(1−5) Lignin offers natural physical and chemical protection to hemicelluloses (H) and cellulose (C); however, when lignin is removed, H and C can be extracted and converted to monomeric sugars, which may be subsequently fermented to obtain ethanol and other added-value compounds.(6−8) The diversity of chemicals derived from lignocellulosic biomasses and the processes involved to produce them gave birth to the concept of biorefinery, which includes several steps for the processing of lignocellulosic feedstocks, with pretreatment and hydrolysis as the key steps.(9−12) Several pretreatment processes, such as acid and alkaline hydrolyses, Organosolv, steam explosion, and twin screw extrusion, among others, have been reported.(13−17) Steam explosion is one of the most successful lignocellulosic biomass pretreatment methodologies, which has gained commercial importance.(18−20)

Our extended group evaluated different feedstocks, such as corn stover, switch grass, palm tree, and BAB, among others, to produce bioethanol and other added-value molecules, using a combination of mechanical and chemical pretreatments. This resulted in the so-called combined extrusion saccharification (CES) process, which includes the combination of alkaline and enzymatic hydrolyses conducted in a modular twin screw extruder (TSE) in a type of reactive extrusion process (REX).(21−25)

Particularly, in our laboratories, we have worked with BAB,(25) because of the availability of this raw material in our country.(26) BAB is a lignocellulosic waste, which results from Tequila production, which, in turn, is one of the most important alcoholic beverages in Mexico, with an annual production of ∼300 million tons.(26−28)

Nowadays, a minimal amount of BAB is used for animal feed or composting.(23) However, most of BAB is either burnt or considered garbage. In this context, the interest in BAB as a potential raw material for bioethanol production,(28−31) and for the production of other chemicals, such as furfural, or as a source of biobased monomers to produce biopolymers has gained importance in the past decade.(27,31) The so-called higher heating value (HHV) is an indicator to measure the efficiency of a fuel. It is useful for the determination of energy content of biomasses and economic analyses, which may aid in determining the efficient use of feedstocks.(32−34) The HHV for BAB is ∼18 MJ kg–1, which is similar to dry wood.(35) In a previous contribution from our group we extensively characterized BAB and found that its content of lignin, hemicelluloses, and cellulose are 18.4, 17, and 38.9 wt %, respectively.(25,36) These composition results agree well with other results reported in the literature: 16–21 wt % lignin, 17–20 wt % hemicellulose, and 30–35 wt % cellulose.(35)

The bold is mine.

300 million tons; that's a lot of bagasse, a lot of tequila. It seems like a high number, could be a misprint, but I really don't know.

The twin screws that made me laugh are actually twin screw extruders. Here's a schematic of the device:

Figure 1. Schematic representation of the screw and barrel, including temperature profile, of a TSE using and alkaline method for deconstruction of BAB.

Again, it's a serious paper. A sample of the sophisticated equations in the a table of about 30 of them.



It's silly, but I'm easy to amuse.

[dweller]

1. 300 million tons ?

😳

Now I know what furfural is …


✌🏻

[NNadir]

2. It's probably going to show up in the corrections section in a subsequent issue.

It has to be a misprint.

Furfural and related furans, such as 5-hydroxymethylfurfural and corresponding carboxylic acids are potentially quite important compounds and a great deal is being written about them, both as fuels and monomers for biobased polymeric materials.

They have the potential to sequester carbon in economically important materials. It's not going to solve the world's problems, but every little bit helps.

[dweller]

3. This may explain a lot

✌🏻

[jmowreader]

4. I did a bit of research here

Last edited Sat Sep 11, 2021, 06:24 PM - Edit history (1)

In 2020, Mexico produced 374 million liters of tequila.

Each liter of tequila requires between 6kg and 8kg of agave pina to produce. We'll use the low number here.

One tonne (1000 kilograms, or 2200 lbs) of pina will produce 166 liters of tequila.

2.25 tonnes of pina will produce 374 liters of tequila.

Therefore, 2.25 million tons of pina will make all the tequila Mexico produces in a year.

They also sell Mezcal, an ancient spirit made from agave (this is the one that's got the worm in the bottle), and undistilled agave nectar so I can see having 3 million tons of bagasse...but not 300 MILLION tons of it.

[NNadir]

5. Your calculation seems much more reasonable.

I think though, that you meant to say "...but not 300 million tons of it."

I'm sure it's a typo by the authors; every issue of this, and most other scientific journals, usually includes some authors' corrections, many of which would not be quite so obvious.

A scary thought is that compared to the dangerous fossil fuel waste carbon dioxide we've been dumping for more than a century, three million is a trivial number.

We now routinely dump, on this planet, 35-40 billion tons per year of that dangerous fossil fuel waste, with another 5 to 10 billion tons being added by land use changes. Thus 3 million tons of bagasse, were it pure carbon dioxide, which of course it is not, would amount to 0.01% of the carbon we dump.

It gives some perspective on the idea that we can remove more than a century of carbon dumping by growing plants.

[panader0]

6. Did you go to Hussongs in Ensenada?

A great and famous old cantina. I had a good time there.

[NNadir]

7. Yes, that's precisely where I got stinking drunk.

In those days, there were a lot of Hussongs bumper stickers around LA. My housemate, who was by the way, an alcoholic, although he ultimately dried out, and I decided we had to check it out. I was LA/beachbum/low life at the time.

It was a bad idea in my case and looking back on that trip, very dangerous. I'm lucky no one was hurt and the only damage was a vomit filled souvenir sombrero.

I don't think I drank anything with tequila in it for about 20 or 30 years, although maybe my wife did. I won't say anything more about screws, this is a family website.