Sciencemadness Discussion Board

Model Chemical Engineering?

Gearhead_Shem_Tov - 10-4-2012 at 02:31

Is anyone interested in the idea of doing model chemical engineering? I'm thinking of this in analogy to model engineering vs. full-scale engineering. Lots of folks build working models of various bits of machinery, the most popular of which is probably the live-steam locomotive.

The attraction of model engineering seems to be the aesthetics of model-building combined with non-trivial engineering. Has anyone tried a similar approach to chemistry? Amateur chemistry, it's often noted on this forum, is inherently small-scale, and so-called chemical engineering problems are thought too big and are thus (at least tacitly) discouraged. But should this be the case?

I'm mostly just thinking out loud, but suppose part of the pleasure to be derived from hobby chemistry came from miniature replication of important industrial processes? Obviously you can't miniaturise 40-meter-tall cracking towers, but there must be lots of other processes where size isn't as critical. I don't have any particular processes in mind, but I'm sure folks here could think of some.

Are there any "legs" to this idea? I'm a sculptor by trade, and I'd be interested in ideas along this line.

-Bobby

gsd - 10-4-2012 at 07:06

@ Bobby,

To begin with browse thru' the pre-publication section. You will find few threads in which miniature Chem Engg is in action. e.g. your fellow countryman has made a working model of electrolytic cell to make Sodium metal.
http://www.sciencemadness.org/talk/viewthread.php?tid=9797

Also Garagechemist's tube furnace to make CS2.
http://www.sciencemadness.org/talk/viewthread.php?tid=10564

gsd

MountainMan - 10-4-2012 at 07:08

I share your interest. There is a great deal of work in at least several areas that might be of interest to you. I'd suggest that you Google 'Flow Chemistry', 'Microreactors', 'Lab On Chip', and/or 'Microfluidics'

I'm relatively new to the forum but have been reading it for several years. My undergraduate degree included a minor in chemistry (1970) and then I switched to Medicine (Pathology) for my career after military service. As I approach retirement, I've made a small biochem and electronics lab as a retirement hobby. I'm:) in the process of building a microscale flow injection analysis (FIA) instrument. First project will probably be to set up a fermentation system using yeast and then using the FIA to monitor byproduct production (ethanol, butanol, etc).

bob800 - 10-4-2012 at 14:09

Quote: Originally posted by Gearhead_Shem_Tov  
Obviously you can't miniaturise 40-meter-tall cracking towers

Or can you?... http://blog.modernmechanix.com/2006/09/03/table-top-oil-refi...:D

Endimion17 - 10-4-2012 at 14:16

Quote: Originally posted by bob800  
Quote: Originally posted by Gearhead_Shem_Tov  
Obviously you can't miniaturise 40-meter-tall cracking towers

Or can you?... http://blog.modernmechanix.com/2006/09/03/table-top-oil-refi...:D


That's an apparatus. I believe his point is to make a miniaturized, working part of a chemical plant. Hence the "model" in model chemical engineering.

Gearhead_Shem_Tov - 10-4-2012 at 18:14

Quote: Originally posted by gsd  

...To begin with browse thru' the pre-publication section. ... e.g. your fellow countryman has made a working model of electrolytic cell to make Sodium metal.
http://www.sciencemadness.org/talk/viewthread.php?tid=9797

Also Garagechemist's tube furnace to make CS2.
http://www.sciencemadness.org/talk/viewthread.php?tid=10564

gsd


Yes, I recall reading through that thread on Garagechemist's exploits with CS2 back then. Very inspiring -- but also quite daunting.

-B

watson.fawkes - 13-4-2012 at 05:55

Quote: Originally posted by Gearhead_Shem_Tov  
I'm mostly just thinking out loud, but suppose part of the pleasure to be derived from hobby chemistry came from miniature replication of important industrial processes?
I'm not so much interested in the model aspect, but I am interested in the miniaturization part, by which I mean I'm not particularly interested in something that looks the same (and also functions), but rather something that has a useful synthesis function. Contrary to ordinary lab practice, which uses reconfigurable glassware, such miniature plants would need to target reusability in its components.

By miniature, I've been thinking that a good target size is 1 - 4 m3 in volume. Dimensional plywood is either 1.2 m x 2.4 m or 2' x 4' (they're very close in size) and a simple box made with 4 full panels for sides and 2 halves for ends comes out to about 3.5 m3. That's "garage scale" or "pallet scale". It's a size that's not so large it couldn't be moved around on wheels or a pallet jack, and large enough to get decent working volume inside.

It's also become really very clear that fabrication skills in multiple materials are paramount. Metal, glass, wood, plastic, and electronics are the obvious ones. It's a combination of skills that are most often found in a club than a single individual. Personally, I'm very bullish on ceramics to be useful here as well, although that will take some development to be useful.

I mentioned electronics because it seems necessary to make such a project work. It used to be that the sensors and control software in a chemical plant were so expensive that it was infeasible to even think about miniaturizing them. That has changed. Solenoid valves are still quite pricey, though I can't figure out where all the expense comes from; they're a candidate for small-shop CNC fabrication.

As for things to make, sulfuric acid is an obvious candidate, as it's the highest volume product of the chemical industry. Nitric acid is another, using cobalt oxide for catalytic oxidation of ammonia. I have a thesis that both of these could be done with ceramics. The square-cube difference works in favor of garage scale for these. I am not confident in the strength of a ceramic pipe 2 m in diameter and perfectly confident in one only 40 mm in diameter.

Another one that I've been gathering materials and parts for is coal tar; the plan is for a barrel-size coking furnace that operates also as a condensing still for dry distillation. I think that one will end up being a two-unit size (7 m3), but only because there's a lot of pipe. Incidentally, coal seems to be a good source of ammonia; ordinary coking furnaces run hot enough to oxidize it. Temperature control throughout the apparatus is paramount for pulling this off.

I've also been mulling over whether making borosilicate glass from scrap flint glass and sacks of borax is feasible. Glass vats need some decent size to avoid too-great heat losses, so that works against the smallest sizes. Also, such glass wouldn't be of the highest purity, with significant iron and manganese in it, but it might well be adequate for shop-made QVF-style cast ware.

arsphenamine - 13-4-2012 at 10:50

Quote:
Solenoid valves are still quite pricey, though I can't figure out where all the expense comes from; they're a candidate for small-shop CNC fabrication.

As I cost out parts for repairing a 30 yr old kinetic sculpture that
<b>shoots flame when you yell at it</b>, I note that the three most expensive items are the
borosilicate cannon barrel, the HV transformer, and the gas solenoid, in that order.

Part of the <b>flammable</b> gas solenoid valve expense is UL certification and product liability.
Without these issues satisfied, the sculpture can never again see a public installation.

I count myself lucky to have found a solenoid valve for under $50.

Gearhead_Shem_Tov - 13-4-2012 at 17:03

Quote: Originally posted by watson.fawkes  
I'm not so much interested in the model aspect, but I am interested in the miniaturization part, by which I mean I'm not particularly interested in something that looks the same (and also functions), but rather something that has a useful synthesis function.
...
By miniature, I've been thinking that a good target size is 1 - 4 m3 in volume. ... That's "garage scale" or "pallet scale". It's a size that's not so large it couldn't be moved around on wheels or a pallet jack, and large enough to get decent working volume inside.
...


I'm very much interested in these ideas, too. I suppose by model I tend to think "semi-scale" because function has higher priority than form for me. (But as a sculptor I am still interested in form.)

"Garage scale" sounds good to me. Or maybe "washing machine scale" (i.e. narrow enough and short enough you can wheel it through a standard doorway). It puts the proper scale on things, so you don't need a ladder or cherry picker just to work on the thing.

-Bobby