Gas Goes Solid

Roland Piquepaille writes "This innovation from Japanese researchers can potentially revolutionize the energy distribution sector. Instead of transporting liquid gas, they changed gas into a solid material which is easier, safer and cheaper to distribute. Technology Review has the story. "Rather than extracting methane from hydrates, they want to turn methane into hydrates -- essentially, transforming the colorless and odorless gas into small pellets that can be easily stored, transported, and eventually turned back into natural gas. A few months ago Mitsui, in partnership with Osaka University, opened a demonstration plant near Tokyo to promote the concept and show that it works." Check this column for an analysis."

Comments

Can anyone speak

[Drakin]

On the quality of minds that work at the U.S. of the sense of people who work at the Department of Energy? Sheesh. this guy's quote is just funny...

Another major advantage: "transporting natural gas as hydrates can be done at lower temperature and pressure than liquid natural gas, and the risk of ignition in transport is much lower,"

The transportation of it will be done at a lower pressure, yes, but at a higher temprature... not a lower one. You need to cool and/or pressurise a gas to form a liquid. Cool and pressurise it more, and you can get a solid... simple changes in the state that the matter is in. Creating hydrates is a chemical reaction... which has differnt prerequsits for happening, and the result is more stable (I assume) where the temprature and pressure don't need to be as strictly monitored.

One problem from the world of ice cream

[Shoten]

Heat shock, it's called. When the temperature of your freezer goes up by even a fraction of a degree (and it need not go anywhere near as high as 0 degrees celsius), some of the ice melts. When the temperature drops again, it re-freezes, but in a slightly different location. That's why ice cream (especially the really expensive stuff, that doesn't have many or any stabilizers like guar gum in it) will develop that coating of ice crystals after it sits in the freezer a while. The ice is migrating from inside the ice cream to the surface.

Now, what I have GOT to wonder is this...what effect might this have on ice pellets that contain lots and lots of tiny bubbles of methane??

Methane hydrates

[panurge]

It's true that there are vast reservoirs on the continental shelf- and a big fear of global warming is that it will cause the hydrates to start dissociating, filling the atmosphere with methane (=powerful greenhouse gas) and accelerating the warming process. It's the speed of warming, not the actual temperature, that is considered to be the biggest problem.

Methane hydrates are not particularly high-energy-density fuels- wouldn't be suitable for automotives, for example-but the bigger a store the easier it is to keep cold (lower surface area to volume ratio) so I guess they could actually be useful as a way of storing large amounts of gas economically and safely, the role they are basically playing on the seabed right now.

Basically, I just don't get the Japanese argument. Is it really going to be cheaper to transport several ordinary refrigerated trucks of methane hydrate than one very cold truck of liquid methane? It looks as if the technology might be more of a way to stockpile large reserves of gas. As electricity generation in many parts of the world is increasingly gas-fired using turbine generators, perhaps this is a way to protect fuel reserves and generator capacity better from terrorists.

Re:Methane hydrates

[stuph]

with regards to the transportation, there are a couple of big bonuses, really

the first is safety.. if a truck full of methane hydrates wrecks, so what, you've got these not-very-harmful rocks slowly melting and releasing methane into the air.. not a big deal..
on the other hand, a tank full of pure, liquid methane would tend to ignite w/ the sparks of any sort of tank cracking.. not good

also, it probably is cheaper to use regular, everyday refrigerated trucks and train boxes rather than getting a tanker truck specially made.. the safety requirements, pressure requirements, etc on one of those are HUGE

Re:Methane hydrates

[Alyeska]

First, safety: The safest method of shipping gas (liquified or not) is by pipeline. If turned to a solid, and overland transportation (train/truck) is necessary, risk goes up tremedously -- compare pipeline accidents to car accidents in the US to get an idea of what you're looking forward to... just because they "melt slowly" doesn't mean it's not an environmental catastrophe if they spill in a neighborhood or highway. With pipelines, you have control.

But there's also the issue of "White Crude," not mentioned here. In Alaska, we have enough gas to fuel the world for years, but can't get it to market because it's so much cheaper to do so elsewhere. We and others are working on a chemical process that creates "White Crude," a room-temperature liquid, from NG. White Crude can be shipped within existing oil pipelines, separated easily at the terminus, and loaded into existing oil tankers. Once at port, white crude can be turned back into NG and distributed through pipelines to consumers.

Re:Things to remember

[Portent]

Actually methane hydrate is much better for transportation than liquid methane for two reasons.

First, it actually contains more energy per unit volume than liquid methane.

And second, it is much more difficult to liquiefy methane than to form the hydrate phase. Liquid form requires very very low temperatures, and very high pressure, while the hydrate phase can be attained at around the freezing point at much lower pressures.

Transporting methane in the hydrate phase is very attractive for countries that don't have their own power sources (southeast Asia). 1 cubic metre of methane hydrate holds 160 cubic metres of gaseous methane.

However, the infrastructure to use it efficiently is still under heavy development so it'll be a while before we see methane hydrate being used on a large scale.

Researched these things

[777333ddd]

Hydrates are quite interesting.

Right out of College about 13 years ago I joined one of those huge Oil Companies and the main thing I did there for 2 years was study gas hydrates. The reason we studied them was in order to *prevent* their formation which is the opposite of what this article talks about. The problem with hydrates in the oil business is that under high pressure and low temperature they form ... and guess what conditions predominate in undersea pipelines?

When oil comes from the formation, it is almost always mixed with water and some varying amount of gas or other hydrate forming HCs. Everything is fine up the wellbore and near the wellhead, but not too far away from the wellhead the fluid starts getting cold and these solid particles form. They can clog a pipeline if you don't take countermeasures. One is to run a device called a "pig" through the pipeline to clean them out. Another is to install insulation, heated lines, or inject lots of chemicals like MeOH to suppress the hydrates. But all of these things start increasing the production cost and/or decreasing capacity.

So our research looked into creating chemicals that you could inject in very small volumes near the wellhead to inhibit the formation of hydrates.

Anyway, all this hydrate study did make people think about the application of hydrates in the transport of natural gas (NG). I think it's a very interesting idea. Currently to get NG from a remote place to market, you need lots of big expensive gas turbines driving massive refrigeration equipment to create Liquified NG (LNG). Then you need these huge, wild looking LNG tankers. Then you need special port facilities to handle the super-cold LNG. The up front capex is so massive (think 10 billion plus for many potential projects) that no one just pays that upfront hoping the customers will show up. No. You get agreements on paper stretching out 30 years with customers and only THEN do you give the green light to the project.

Hydrates certainly wouldn't need near the compressor/turbine expense of LNG development, and there might be a sweet spot in terms of pressurization and temperature you might strike. However the rest of the economics I'm not too sure about. If most of the cost of a project is the tankers and you need a lot more of them for Hydrate, then you might be better off with LNG. The other huge thing in LNG's favor is that we know it works and can calculate a cost.

One interesting idea I saw floated once was the creation of hydrate subs. Huge deepsea vessels that would be able to stay cold and high pressure just by virtue of being well below the sea surface where those conditions are natural. Now unlike a typical sub, these guys would never surface and so would not need thick walls to handle pressure differences inside and out.

Imagine one of these things scooping up hydrate from the ocean floor and carting it off to a disassociation plant on the seabed (preferably in a subsea canyon as closs to the coast as possible) that evaporated the hydrate gas into a regular gas pipeline.

dave