Others' Related Patents.

Nuclear Methanol and Gasoline.
Nuclear Diesel
Sea Fuels
CO₂ Electrolysis
Junk Science
Conventional FTS
(Click here for the References page)

Nuclear Methanol and Gasoline. Martin and Kubic of Los Alamos National Laboratories have recently suggested that a novel approach to electrolytic rejuvenation of an aqueous solution of CO₂-laden K₂CO₃ may permit lower-cost separation of CO₂ from the atmosphere. They then propose that this CO₂, along with hydrogen from water electrolyzed by nuclear energy, be converted to methanol and then to gasoline in a process they call “Green Freedom™”.

Their primary innovation is an improved method of separating CO₂ from the atmosphere, though it is not clear from the available information that they have made a significant improvement here. Martin’s process, like most others, would require enormous amounts of low-grade heat and low-cost high-quality water. It would certainly be much more expensive than using upgraded conventional technologies to separate CO₂ from the exhaust of natural gas or coal-fired power plants (where the concentration of CO₂ is nearly three orders of magnitude higher than in the atmosphere), as we propose.

The next big problem is what they propose to do with the CO₂. They clearly have not figured out how to make the RWGS reaction work efficiently (as we have); so they propose to make methanol from a syngas consisting of just CO₂ and H₂ (mostly from electrolyzed water) rather than using the more efficient processes that usually have a ratio of CO/CO₂ greater than 3 and have always had this ratio greater than 1. It is true that methanol can be synthesized without CO in the syngas, but the process has not been commercialized because it hasn’t worked as well. Mitsui will soon attempt to demonstrate CO₂-to-methanol in a very small pilot plant in which at least some of the hydrogen will be generated by solar photolysis and some will probably come from solar PV. Almost no technical details are being made public, but the catalyst being used appears to be the same as that used in a bench-scale demonstration a decade ago (Kenji Ushikoshi et al, Applied Organometallic Chemistry 14, 819-825, 2000), Cu/ZnO/ZrO₂/Al₂O₃/SiO₂. The process achieved very high selectivity, but very low conversion per pass, so it still required separations, recompression, and recirculation. Indeed, the process is much simpler than fully recycled FTS, but the product is just methanol. Several other CO₂-to-methanol processes are also in development, including one that apparently has useful yield at room temperature, but it starts with an expensive hydrosilane precursor. There will be no shortage of cheap methanol from coal, methane, or biomass for at least the next 25 years.

Another (and bigger) problem is that Martin plans to power their plant using a huge nuclear reactor – four times larger than most that have been built. Nuclear power has never been cheap, and it is steadily becoming more expensive. It has competed thus far only because of enormous subsidies (in the research, development, fuel processing, security, waste storage, etc.), and these are increasingly harder to support politically. The Union of Concerned Scientists and most other environmental organizations do not support ramping up nuclear energy – primarily for safety reasons.

Their nuclear-generated methanol cannot compete with fossil-derived methanol. The price of methanol has spiked severely on a few occasions in recent history, largely due to some process plant problems in Chile and natural gas price spikes in the U.S. However, methanol plants are being built fast enough in China, Qatar, Iran, Russia, and elsewhere to insure that the price of methanol (per unit energy) should average well below the cost of all other transportation fuels for many years.

The latest research indicates that electrical energy will cost about $90/MWhr ($25/GJ) from new nuclear plants that would be ordered next year in the US – or over five times as much as off-peak wind energy. (See our comments on nuclear fission.) If we assume 55% conversion efficiency and add (very conservatively) about 25% for a few other cost components, the “nuclear methanol” from their process will cost about $1/kg. The mean price of methanol for 2009 was ~~$0.25/kg, and in mid 2010 it was $0.35/kg. No one will pay three to four times as much for “nuclear methanol” as for methanol from natural gas or coal. Their “nuclear gasoline” would cost at least $7/gal.

Since methanol has not been accepted as a major component of gasoline in the U.S. and most industrialized nations, they propose to convert the methanol to gasoline using conventional processes (such as the ExxonMobil MTG process). These processes have achieved 85% efficiency in production of gasoline. Undoubtedly, the processes can be improved, and methanol-to-gasoline processes are likely to play a larger role in the future as enormous amounts of renewable methanol become available from WindFuels.

Finally, it is important to return to a sub-theme in the first point – the fundamental market reason for abandoning the CO₂-to-methanol route that has been advocated by Nobel Laureate George Olah for many years. Mid-alcohols and light olefins have been 20%-70% more expensive per unit energy than methanol over most of the past five years and that relationship is likely to continue – partly because of an undeniable trend in agricultural commodities. If expensive energy is to be used to make carbon-neutral products, the products should be mostly those with the highest value per unit energy – jet fuel, mid-alcohols and light olefins. We have shown that these more valuable products can ultimately be made at higher efficiency than others have yet achieved in the production of methanol.

Nuclear Diesel. Severinsky is to be commended for the valiant efforts in his pending patents (U.S. published application 2006/0211777, etc.), as his work is mostly sound – to the extent that it can really be evaluated. Basically, he has attempted to patent the general process of making carbon-neutral fuels (diesel and gasoline) using the RWGS reaction and the FTS reaction. He thinks the best source of the hydrogen would be nuclear reactors electrolyzing water, but he realizes other renewable energy and other processes could also be used.

The problem of course is that the above general concepts have been discussed since the mid-1970’s. Severinsky collects a lot of relevant technical information and presents a variety of different plant designs in very general and confusing language. He makes claims about efficiencies that he thinks are possible, but provides no clear explanations of how or why his ideas are better than what has been done before. While most of the details on the various components he describes are sound, his system designs (which is what he is attempting to claim) are completely unintelligible (even to an expert who has spent years trying to understand such things).

One test is to ask: “Is there anything in his patent of value that was not really present in the prior literature?”. Another is to ask: “Is it likely that anyone on a technical team designing and developing an RFTS plant would ever take a second glance at his patent when trying to scope out the design, understand the plant, or optimize some process?” The answer to both is a resounding no.

It is not surprising that the initial PCT written opinion (9/2007) stated that none of his claims contained an inventive step. Of course, he will likely revise them and eventually get some very narrow claims allowed. Patent attorneys and inventors without sufficient relevant experience often propose very broad claims in the initial submission because they think their claims will be worth less if narrowed by additional specifics. However, a narrower claim is not worth less if there is not a better way of accomplishing its objective. The real problem with starting with overly broad claims is that the specification may not have been written in such a way as to support valuable claims that could be granted – and significant amendments in the specification after formal submission are seldom allowed. Most likely, his claims will end up including restrictions that are suboptimal and will never be practiced, such as: the use of an electrolyzer operating very near the thermo-neutral potential, the use of a heat pump for transfer of energy from the FTS reactor to the RWGS reactor, the use of specific phase-change liquids for heat transfer, FTS conditions suitable only for production of diesel with specific catalysts, and the use of a fission reactor. The Written Opinion of the International Searching Authority makes it clear that Severinsky’s pending patent is of no concern to us.

Sea Fuels. Behrens has proposed in US Pat 7,302,903 (12/2007) that wind energy could be used to produce hydrocarbons from seawater in floating vessels. One of the showstoppers with his concept is that it utilizes CO₂ that has already been sequestered in the ocean, so it is no better for the climate than fossil fuels. Another showstopper is that it would add the cost of a ship the size of an aircraft carrier to the cost of the small RFTS plant that it would support. And there are numerous other technical problems too, but there is no point in continuing here. However, Behrens’ patent does provide an interesting example of how severely the scope of the claims must be limited in this subject area when substantive technical innovation is not supported in the patent’s specification.

The idea of taking CO₂ from seawater and making fuels from it is actually more flawed than the notion of taking CO₂ from the atmosphere. The atmosphere is approaching 400 ppm CO₂, but ocean surface waters are typically only 90 ppm CO₂ (including H₂CO₃, carbonic acid) by mass so an enormous amount of seawater would need to be handled, cleaned, and de-gassed. (The advocates of this approach like to say the concentration of CO₂ in seawater is 140 times its concentration in air. That is roughly true in terms of kg/m³, but that is irrelevant when it comes to the separation problem.) The theoretical minimum amount of energy required to separate CO₂ from the atmosphere is 7 times more than from point sources, but in practice it has taken about 20 times more energy thus far. The proposed vacuum methods for separating CO₂ from the ocean fail to appreciate that even after separating the enormous amount of H₂O vapor (85-98%, depending mostly on the temperature selected, preferably just above freezing) from the flash overhead, the non-condensable gas in the overhead will still be under 15% CO₂, with the balance being N₂, O₂, and Ar. Hence, complex gas separations will still be required. We estimate that, in practice, taking CO₂ from the ocean will take 30 times as much energy as separating CO₂ from point sources, though we have not looked carefully at all process optimization possibilities.

More Sea Fuels and Methanol Routes at the DoD. Dennis Hardy, in US Patent 7,420,004, claims the synthesis of hydrocarbons via a CO₂ to methanol to hydrocarbons process using Fischer-Tropsch catalysts. The independent claim is extremely broad, and probably wouldn’t survive a court challenge, as there is virtually no substantive, innovative material in the specification. Some of the dependent claims might survive, such as those that require taking the CO₂ from seawater – but that is a very bad idea, as discussed above. They mention various renewable energy sources, but the primary focus is nuclear.

The independent claim requires first producing methanol for feeding into the FT reactor. This route from methanol to hydrocarbons is less effective than many other options (such as the ExxonMobil MTG process). Perhaps more importantly, no one is going to make expensive renewable methanol from expensive energy and CO₂ for at least the next 25 years, as fossil methanol will remain too cheap. Of course, the WindFuels process will produce methanol, but it will also be producing larger streams of other, more valuable products – jet fuel, gasoline, and ethanol.

A recent publication by a research team that includes Hardy at the Naval Research Laboratories (NRL) has generated some media attention. Their focus has apparently turned to hydrocarbons via direct hydrogenation of CO₂, but with less success than others have achieved, as the unwanted methane selectivity is very high.

We have a few comments in
http://dotyenergy.com/PDFs/WindFuels_Sci_Engr_ppt.pdf showing why it is extremely unlikely that direct hydrogenation of CO₂ will ever compete with the RWGS route. A more detailed explanation will appear in a future publication.

CO₂ Electrolysis. Stoots et al in US Pub 2008002338 disclose a method of producing a CO+H₂ syngas by electrolyzing a steam/CO₂ mixture at high temperatures. One of the showstopper problems with their invention is that is requires a ceramic electrolyte, and the best option that anyone has come up with over the past two decades of related work in high-temperature steam electrolysis is zirconia.

Few companies have more experience with zirconia at high temperatures and high stresses than Doty Scientific. We know all too well how fragile and expensive zirconia is. Reliance on zirconia ensures that neither steam electrolysis nor steam/CO₂ electrolysis will ever work in the real world. Even if they could make it work with acceptable lifetime (irrespective of the cost of the electrolytes), it does not appear that they could offer any efficiency advantage in an RFTS plant. There has simply been too much progress recently in water electrolysis, and off-peak electricity is becoming too cheap for anything else to compete.

Junk Science. Seymour’s work in US Patent 7,238,728 (7/2007) and elsewhere is a classic example of the kind of stuff that gives patenting a bad name. Most patents simply prove to be uncompetitive in the real world; but some, like this one, are poorly conceived or vague ideas by individuals with just enough technical expertise to convince an unqualified patent attorney that they have a good idea. (They sometimes are even able to convince investors.)

Seymour seems to understand that syngas (CO and H₂) can be converted to liquid hydrocarbons in an FTS reactor and that the combination of partial combustion and pyrolysis of biomass can produce syngas. He apparently also understands that the mixture ratio may need adjustment, and that electrolysis of water produces hydrogen and oxygen which should be able to be used in the process. So he proposes to: (A) send some of the H₂ and O₂ along with some waste CO₂ into a gas turbine; (B) generate heat to assist in the pyrolysis; (C) reduce some of the CO₂ to CO; (D) separate the CO from the turbine products; (E) feed a proper syngas mixture into the FTS reactor; and (F) collect the reaction products.

There is no way such a process could ever be made to work at efficiencies even a quarter of what we’ll achieve. For starters, one cannot have turbine exit conditions that permit the combination of (A) efficient utilization of its remaining enthalpy in pyrolysis, (B) high CO fraction in the turbine exhaust, and (C) efficient separation of the turbine products (CO, CO₂, and H₂O). It also seems silly to deliberately design an inefficient turbine (as needed to get the desired pyrolysis heat), especially when burning electrolysis hydrogen; and there are a host of other detail issues that the inventor has not begun to think about.

The patent examiners don’t worry about patents like this as long as they don’t obviously violate the second law of thermodynamics. They might suggest some claim language that is clearly of no value and quickly have the patent allowed to get it off their desk. This one issued only 11 months after it was submitted. It is completely worthless and of no concern to us.

Conventional FTS. Andre Steynberg and colleagues disclose in pending US patent 2007/0142481 an improvement on a two-stage FTS reactor arrangement. In this design, the syngas first partially reacts in a 3-phase LT-FTS reactor, and its tail gas (some products and un-reacted syngas) then go to a 2-phase HT-FTS reactor for further reaction. This approach appears optimum for their desired balance of mostly lubricants, high-quality waxes, linear alkyl-benzenes, gasoline, diesel, and some light olefins and oxygenates from coal-syngas. This is a beautifully written reference by the world’s best team in fossil-based FTS, but there is little here that can be applied to renewable, carbon-neutral products. Two other nice reference patents on fossil FTS are US Pat # 7,001,927 by Zhang and US Pat # 7,115,670 by Hensman and Newton.