Sulfuric Acid on Mars

kbd512 · 2018-08-04 04:39:42

Josh,

NASA has a number of documents on NTRS that characterize the Sulfur compounds commonly found on Mars. A quick Google search will reveal those documents. The short and simple answer is that the Sulfur deposit composition and concentrations vary by location, but formerly volcanic regions yield rich deposits. Some of those deposits were encountered just below the surface and revealed by the tracks made by our rovers.

Oldfart1939 · 2018-08-04 06:07:47

The $100 Million is based on my experience in plant design. These reactors built with special products in mind, eg., highly corrosive, tend to be VERY spendy. Having a type 316 SS body with glass lining thermally bonded would run about $250,000 for a small pilot scale system--maybe 50 to 75 gallons working capacity. The cost isn't really linear for scale up either. The larger reactors require better mechanical seals for containment, and everything else if PTFE for union gaskets. My WAG for a 5,000 gal reactor built to the standards I have prescribed is on the order of $25 million. And that's just ONE PIECE in a plant. There would undoubtedly be several 10,000 gallon holding vessels at roughly $10 Million apiece. Not to mention all the physical structure custom built to hold all these reaction components. I would be looking towards using this size setup initially, until we would have a decent estimate of the quantities really needed. No plant engineer would stop with just one such reactor; there would be built-in redundancy. I could blow through that $100 million in a hurry.

Oldfart1939 · 2018-08-04 06:09:23

P.S. I paid $75,000 for a 10 gallon system about 15 years ago, and the stuff from Pfaudler hasn't become any less expensive!

JoshNH4H · 2018-08-04 15:18:18

Thanks to kbd512's helpful suggestion to look on NTRS, I've been doing some research on the potential for reduced sulfur (IE, SO2, S, H2S, disulfides (pyrite, also known as fool's gold is the most common) or sulfides as opposed to sulfates) in accessible portions of Mars.

The tl;dr of my research is that the outlook for sulfuric acid feedstock is not good, but I'll go into more detail below.

First, the good: Mars is a high-sulfur planet. Indeed, its core is probably an iron-sulfur core (as compared with nickel-iron on Earth). Furthermore, Mars has some really giant volcanoes and virtually its entire surface is formed by igneous material, which is generally associated with un-oxidized sulfur.

Now here's the bad news: Mars hasn't had substantial volcanic activity in a long time and the environment is deeply oxidizing. Iron exists primarily in the ferrous (3+) form, and hardly at all in the ferric (2+) form; the soil may also contain perchlorates and peroxides.

Basically, what the evidence suggests is that Mars has lots of sulfates and very little of any form of sulfur that might be useful.

This paper suggests that the Spirit rover may have found some pyrrhotite in Gusev crater, but probably not in mineable concentrations. The Phoenix lander seems to have determined that most of the sulfates where it landed (northern Vastitas Borealis) are Na, K, or Ca sulfates and not, for example, Iron Sulfate (which you might be able to smelt with Hydrogen to produce usable Iron and sulfuric acid).

Anyway, it's bad news as far as sulfur is concerned. The caveat applies that Mars is a big planet that is mostly unexplored, and even if sulfur resources are not a typical feature of Mars they may exist somewhere. This isn't necessarily a good thing, as it could mean you're sending mining convoys thousands of kilometers away (possibly climbing up a great volcano or digging down to a volcanic spring) to get your sulfur feedstock.

Does this agree with what you found, kbd512?

JoshNH4H · 2018-08-04 19:11:32

Oldfart1939 wrote:

P.S. I paid $75,000 for a 10 gallon system about 15 years ago, and the stuff from Pfaudler hasn't become any less expensive!

Can you explain what this item was doing and what went into it that made it cost so much?

Also, maybe you said it somewhere else and I missed it--it sounds like you have a lot of professional experience in the chemical industry, where does that come from?

kbd512 · 2018-08-04 19:27:05

Josh,

Your assessment of the Sulfur bearing compounds found on Mars matches my own, but I'm not a chemical engineer. Oldfart1939 should read through the available literature and tell us what he thinks based upon his decades of chemical engineering experience. I think people are going to be unpleasantly surprised with how difficult it is to obtain feedstocks of raw materials in usable forms and quantities. It's not impossible, but decidedly energy-intensive.

Louis,

How much product are we talking about making? Could you run that down for us?

Oldfart1939,

Could you explain to us what the principle problem is with the SO3 and H2O reaction?

Why can't we just mix small amounts of precisely metered reactants using spray nozzles and large chambers to collect the product, for example?

JoshNH4H · 2018-08-04 19:48:59

My guess on the SO3 hydration reaction is that it's so exothermic that combining SO3 and H2O at a 1:1 molar ratio will produce some extremely hot acid.

From the NIST chemical web book is looks like the energy of formation of H2SO4 is -1295 kJ/mol, vs -285 kJ/mol for water and -340 kJ/mol for SO3, so that reaction produces about 670 kJ/mol of H2SO4. I think that's why they produce it slowly, mixing in a bit of SO3 with a 98% solution of H2SO4 to strengthen it up to 99%, skim off 1% of that as product, dilute it down to 98%.

I can definitely see why you wouldn't want to try to handle scalding hot sulfuric acid.

kbd512 · 2018-08-04 21:56:05

Josh or Oldfart1939,

I get that it's a very energetic reaction, but I'm talking about mixing the reactants slowly. It's the difference between a lighter and a blow torch.

Both produce a flame that's pretty hot, even though the torch is obviously hotter than the lighter, but limiting the flow of reactants should keep the thermal environment manageable, right?

Why can't we use expanding CO2 to moderate the temperature of the reaction vessel?

Has anybody thought about using continuous production processes and coolant gases like CO2 to simultaneously produce product, heat, and power?

Maybe it's not economically feasible on Earth, but I think a lot of the tech developed for Mars will be somewhat unique to Mars. We can't use the same "lowest possible production cost" mindset that only makes sense on Earth where the cost of processing raw materials drives the manufacturing methods. Labor and electrical power are at a premium on Mars, but the use of more expensive manufacturing methods is just the cost of doing business.

Oldfart1939 · 2018-08-05 01:21:21

First, let me enter a correction to that which was stated earlier. The Fe+2 is the Ferrous form, and Fe+3 is the Ferric form.

There was a question about my background, so here it is in not too small a nutshell.

Started my education at University of Colorado, 1957, major: Aerospace Engineering; after 3 years, lost my motivation to be an engineer because realized I was more suited to being a basic physical scientist-researcher. Took 3 years out in U.S. Army.

Returned to University of Colorado and finished B.S. Chemistry, 1967.

Worked in industry for a year while making Graduate School applications; Sigma Chemical Company, St. Louis, MO. THE #! supplier of research biochemicals worldwide. Position: Supervisory staff chemist in analytical chemistry.

Entered grad school, University of Wyoming, 1968. Completed Ph.D in Physical Chemistry 1972; specialty: Molecular Photochemistry.

Postdoctoral: NIH National Eye Institute, U. California, Santa Cruz, CA. Study of eye as an energy transducer and how incident photons are converted to neural electrical signal. 1972-1975.

Research Associate, Stanford University Medical School; Set up analytical program for Department of Nephrology.

Private Industry from 1976 until retirement 2005. Established 2 companies, designed and built plants and laboratories for both.
Came out of self-imposed retirement to start a polymer chemistry program for a client in Oregon as Director of Polymer Chemistry. Worked with reaction facilities utilizing multiple 5,000 gallon jacketed and pressurized reactors. Metric Tonne output of products. Finally retired 2009.

Currently retired and enjoying life. Especially enjoy engaging in chain-pulling on scientific sites. Presently in Germany doing sightseeing and other activities.

My earlier flippant comments aside, I am VERY serious about making mankind a multiplanetary species, in a manner similar to Elon Musk but without his financial wherewithal.

Last edited by Oldfart1939 (2018-08-05 06:08:16)

Oldfart1939 · 2018-08-05 05:43:13

If anyone here besides myself has handled much Sulfuric Acid, recall the warnings about dilution! The heat of dilution is enormous. The rationale of adding acid to water is based on the propensity of spattering on the operator, and that spattering dilute and not superheated and still concentrated acid is behind the suggestions.

If the availability of Sulfuric Acid is deemed essential to manufacture of solar panels, then that project should be delayed until other useful projects can be undertaken.

Oldfart1939 · 2018-08-05 06:19:30

I just noted that one of the posts I thought I made isn't here. But to briefly reiterate, the problem is one of cooling but along with containment. Here on Earth, containment is necessary due to the extreme hygroscopic nature of the concentrated acid, which actually "sucks" water from the air and dilutes it. The containment is important to manufacture a known and highly reproducible product. I guess if we wanted to do nothing besides manufacture H2SO4 for PV manufacture, we could dedicate most of the workforce to monitoring and operating small reactors. However, I believe there are more important fish to fry, and that is plastics production for habitat construction. I don't think manufacture of Sulfuric Acid should be conducted in anything less than 5,000 gallon reactors, or manufacture of ~ 10 Tonnes per reactor run.

Terraformer · 2018-08-05 06:44:04

Is there any way we could extract SO3 from Sulfurous Acid? Reacting it with chlorine, perhaps, to remove the hydrogen?

SpaceNut · 2018-08-05 08:04:32

The real trouble with all of this or other think tank topics is keeping what we want to do goal with each item that we think we want, making applicable to more than just one process or use and keeping the equipment costs sent from earth in mass and dollars to the lowest levels and finally what a else can we do view with the same equipment that we send.

JoshNH4H · 2018-08-05 08:57:44

Terraformer wrote:

Is there any way we could extract SO3 from Sulfurous Acid? Reacting it with chlorine, perhaps, to remove the hydrogen?

I don't think there's much H2SO3 on Mars either? There's also a bunch of nasty compounds with H, S, O, and Cl in them so selectivity is probably low.

Oldfart1939 · 2018-08-05 09:18:51

Extracting SO3 from H2SO3 isn't possible since the oxidation number of sulfur is only +2.

H2SO3 is sulfurous acid formed when SO2 is dissolved in H2O; ------------> H2O + SO2 -----> H2SO3.

In reality, the only way the production of Sulfuric Acid makes any economic or scientific sense is when there is PURE ELEMENTAL SULFUR readily available. Not as some other salt form which is energetically difficult to decompose.

What has been entirely overlooked by most here, is that when we have the reactors, tankage, etc., we still need to house or otherwise enclose from the hostile Mars environment what would amount to $100 to $150 Million Earth based dollars of equipment weighing >> 100 Tonnes awaiting transportation to Mars. So...anyone wanting a nascent chemical industry so we can make a gazillion solar panels should get ready to pony up around...a Billion Big ones.

Oldfart1939 · 2018-08-05 09:23:11

SpaceNut-

I'm really glad this is a think tank topic, otherwise I'd be wondering about those Angels getting their dance routines rehearsed.

JoshNH4H · 2018-08-05 10:14:23

Oldfart1939 wrote:

Extracting SO3 from H2SO3 isn't possible since the oxidation number of sulfur is only +2.
H2SO3 is sulfurous acid formed when SO2 is dissolved in H2O; ------------> H2O + SO2 -----> H2SO3.
In reality, the only way the production of Sulfuric Acid makes any economic or scientific sense is when there is PURE ELEMENTAL SULFUR readily available. Not as some other salt form which is energetically difficult to decompose.
What has been entirely overlooked by most here, is that when we have the reactors, tankage, etc., we still need to house or otherwise enclose from the hostile Mars environment what would amount to $100 to $150 Million Earth based dollars of equipment weighing >> 100 Tonnes awaiting transportation to Mars. So...anyone wanting a nascent chemical industry so we can make a gazillion solar panels should get ready to pony up around...a Billion Big ones.

I don't think this post is accurate in context. Using solar panels as a representative example, let's say 1% of the cost of your panels would be acquiring sulfuric acid. Let's say that the poor availability of Sulfur means that you need to smelt it directly out of Iron (III) Sulfate instead using hydrogen, which doubles the unit cost.

Your solar panels now cost 1% more. If solar was the best way to generate power before, it almost certainly still is. It's true that, on Earth, a competing process that costs twice as much will not succeed. But on Mars, you have no competition (alternatively, your competition has the same constraints as you do, or is importing product from Earth at thousands of dollars per kilo). Mars has some advantages but many disadvantages and our challenge is to figure out how to overcome them. I'm sure you wouldn't argue that it's impossible to obtain sulfur from sulfates, just expensive. It's probably never been done on an industrial scale in Earth. We can hope that better resources can be found, but if they can't we can figure out how to deal with that and implement the best solution we can come up with.

I think we would all agree also that there will come a time, if settlement is successful, when just about everything will have to be produced on Mars. They certainly can't keep importing any product that uses Sulfuric acid from Earth forever.

As far as buildings go, I have some designs for locally constructed buildings that I would be glad to share in full detail in another thread if you're interested.

I respect your impressive experience, but I also recognize that with experience often comes a certain attitude, that the way things are done is the only way things can be done. As the saying goes, "If an experienced and well-respected engineer says something is possible they are almost certainly right; If they say something is impossible they are almost certainly wrong".

JoshNH4H · 2018-08-05 22:39:13

To expound on sulfates a bit:

Per this paper, Ferric Sulfate will decompose into Fe2O3 and SO3 when heated to temperatures around 1000 K. Per the image at the end of this report:

This is also the case for various other sulfates.

It is believed that sulfates on Mars exist indirectly due to volcanic activity several billion years ago. Mars' atmosphere at one time had substantial amounts of SO2 gas, which was oxidized, and reacted with water to form sulfuric acid. This slowly reacted with oxides and carbonates to form sulfates in the soil.

Anyway, this means that there's actually substantial hope for the existence of good sulfate reserves as the sulfate minerals that exist will have precipitated out of standing bodies of water and you might find a decent slab of usable sulfates somewhere.

You might heat the sulfates as part of a batch process to bake out the SO3 and probably also some SO2 (if there are any Iron (II) Sulfates mixed in. From there you can proceed as in the contact process, catalyzing the remaining SO2 to SO3, and then reacting it with water in a concentrated sulfuric acid to get purer sulfuric acid.

I know it's untraditional, and I'm probably oversimplifying the process, but it seems workable. Thoughts?

Oldfart1939 · 2018-08-05 23:18:54

Nothing was ever said about getting Sulfur from other forms being "impossible," but systemically just "very difficult." And energetically very expensive. In the chemical process field, anything above superheated steam temperatures present extreme difficulties, since this is in a range where the seals in systems are subjected to almost impossible stresses. Most seals today are made of PTFE, which would not withstand such temperatures under high pressures involved. Yes. Things are always "possible;" on paper.

Oldfart1939 · 2018-08-06 06:25:02

I see nothing in the flow diagram to indicate the liberation of any SO3. All I have is your interpretation to mean there is some? I wouldn't bet the farm on one of these processes as my first interpretation.

Oldfart1939 · 2018-08-06 06:33:44

A general comment on expense of industrial chemical processes. Every step added increases the infrastructure requirement in a major way, and one can figure on it being a 2x multiplier. The textbooks may say otherwise, but the bean counters say it's a killer to any economic outlook.

louis · 2018-08-07 10:54:06

From the self replicating colony thread, I posted: "Proportionately for a colony of 1000 (assuming Earth's population is about 7 billion) that would mean on Mars we would need a maximum of just over 14 tonnes per annum or about 39 kgs per sol." So that's based on one seven millionth of world production of sulphuric acid.

14 tonnes per annum might be right, but I can see it could be lower (because we don't have to produce as much plastics, private vehicles, hydrocarbon energy, paper, etc etc) or could be higher (because you are having to provide a broad industrial infrastructure at a low economy of scale).

kbd512 wrote:

Louis,
How much product are we talking about making? Could you run that down for us?

Oldfart1939 · 2018-08-07 13:14:02

Louis-

I suspect you are underestimating the amount of Sulfuric Acid per capita in the CIVILIZED world. Obviously many 3rd World counties with large populations utilize little to none. 14 Tonnes annual production would not happen based on economics. What this will take is INVESTMENT, and nobody is going to pony up the necessary money to build and transport a sulfuric acid plant to Mars for the revenue it would generate. In order to amortize the investment necessary to manufacture 14 Tonnes, it would have to sell for roughly $1.5 million per Tonne. I used a 5 year investment recapture buydown for a $1 Billion plant investment. Nothing was even added in for cost of the feedstocks or necessary labor to operate said plant--much less make a profit that would spur it's construction.

louis · 2018-08-07 14:13:46

This was an offshoot of the self-replication thread, so I was thinking more in terms of that, than Earth investment.

However, even allowing for that, it is clear to me that a Mars colony would have multi-use industrial facilities. A container that can hold sulphuric acid can hold other acids. My understanding is that tankers on Earth do hold different acids and are flushed after use before another acid is loaded.

I think we would design in small scale multi-purpose facilities so that the same hab space could be used to produce a range of chemicals and also manufacture a range of final goods.

I really don't see any need to seek Earth investment to build a Mars sulphuric acid plant. As long as we have the equipment to manipulate steel, glass, ceramics and plastics, we can build sulphuric acid manufacturing facilities. We might import computer control equipment, thermocouples and the like, as they can probably be produced on Earth much more easily. The sulphuric acid doesn't need to be "sold" to anyone - it can just be used. I think moving away from a command economy to a proper functioning market economy with currency pricing of goods would take several decades at least and would require the establishment of a range of market participants including individuals, private and public companies, public corporations and co-operatives. A fully functioning market economy won't spring up of its own accord...or rather it would have a very limited focus if you allowed it to.

Oldfart1939 wrote:

Louis-
I suspect you are underestimating the amount of Sulfuric Acid per capita in the CIVILIZED world. Obviously many 3rd World counties with large populations utilize little to none. 14 Tonnes annual production would not happen based on economics. What this will take is INVESTMENT, and nobody is going to pony up the necessary money to build and transport a sulfuric acid plant to Mars for the revenue it would generate. In order to amortize the investment necessary to manufacture 14 Tonnes, it would have to sell for roughly $1.5 million per Tonne. I used a 5 year investment recapture buydown for a $1 Billion plant investment. Nothing was even added in for cost of the feedstocks or necessary labor to operate said plant--much less make a profit that would spur it's construction.

Oldfart1939 · 2018-08-08 00:35:31

louis wrote:

I think we would design in small scale multi-purpose facilities so that the same hab space could be used to produce a range of chemicals and also manufacture a range of final goods.

Louis-your total lack of knowledge is showing here. Not all processes can be carried out in some basic simple reactions system, especially one involving containment of the by-products of reaction, as well as the product itself. The chemical industry is very specific in cross usage of equipment, especially if pharmaceuticals are at all involved--even feed stock for pharmaceutical products.

Louis wrote:

I really don't see any need to seek Earth investment to build a Mars sulphuric acid plant. As long as we have the equipment to manipulate steel, glass, ceramics and plastics, we can build sulphuric acid manufacturing facilities. We might import computer control equipment, thermocouples and the like, as they can probably be produced on Earth much more easily. The sulphuric acid doesn't need to be "sold" to anyone - it can just be used. I think moving away from a command economy to a proper functioning market economy with currency pricing of goods would take several decades at least and would require the establishment of a range of market participants including individuals, private and public companies, public corporations and co-operatives. A fully functioning market economy won't spring up of its own accord...or rather it would have a very limited focus if you allowed it to.

I really think you should re evaluate what you have written here. Your views on economics are totalitarian and would be more at home in the former Soviet Union than on Mars!

Everything you are "wishing into existence" needs paid for--by someone or by some means. The comment that "sulphuric acid doesn't need to be 'sold' to anyone--it can just be used." comment really blew my mind.

New Mars Forums

Announcement

#26 2018-08-04 04:39:42

Re: Sulfuric Acid on Mars

#27 2018-08-04 06:07:47

Re: Sulfuric Acid on Mars

#28 2018-08-04 06:09:23

Re: Sulfuric Acid on Mars

#29 2018-08-04 15:18:18

Re: Sulfuric Acid on Mars

#30 2018-08-04 19:11:32

Re: Sulfuric Acid on Mars

#31 2018-08-04 19:27:05

Re: Sulfuric Acid on Mars

#32 2018-08-04 19:48:59

Re: Sulfuric Acid on Mars

#33 2018-08-04 21:56:05

Re: Sulfuric Acid on Mars

#34 2018-08-05 01:21:21

Re: Sulfuric Acid on Mars

#35 2018-08-05 05:43:13

Re: Sulfuric Acid on Mars

#36 2018-08-05 06:19:30

Re: Sulfuric Acid on Mars

#37 2018-08-05 06:44:04

Re: Sulfuric Acid on Mars

#38 2018-08-05 08:04:32

Re: Sulfuric Acid on Mars

#39 2018-08-05 08:57:44

Re: Sulfuric Acid on Mars

#40 2018-08-05 09:18:51

Re: Sulfuric Acid on Mars

#41 2018-08-05 09:23:11

Re: Sulfuric Acid on Mars

#42 2018-08-05 10:14:23

Re: Sulfuric Acid on Mars

#43 2018-08-05 22:39:13

Re: Sulfuric Acid on Mars

#44 2018-08-05 23:18:54

Re: Sulfuric Acid on Mars

#45 2018-08-06 06:25:02

Re: Sulfuric Acid on Mars

#46 2018-08-06 06:33:44

Re: Sulfuric Acid on Mars

#47 2018-08-07 10:54:06

Re: Sulfuric Acid on Mars

#48 2018-08-07 13:14:02

Re: Sulfuric Acid on Mars

#49 2018-08-07 14:13:46

Re: Sulfuric Acid on Mars

#50 2018-08-08 00:35:31

Re: Sulfuric Acid on Mars

Board footer