Water from Gypsum By Steam Injection
Here’s one one interesting idea for getting water to desert regions. Consider gypsum. There’s lots of it in the southwest. The chemical formula for gypsum is CaSO4.2H2O. Notice the H20 on the end? Gypsum is 20% water by weight. Did you know that you can quickly cook the water out of gypsum at 212F degrees 100C . Gypsum occurs in flat planes often not far from the surface–especially in old dry lakebeds. You could cook those planes. Leaving a mineral residue called bassanite–water would percolate up and the earth would subside causing a lake. Think you could find a heat source in the desert? Maybe flared off gas? Maybe solar power? Maybe a coal plant somewhere. 212 degrees isn’t too hot. Hmm 212 is a familiar number. You might use steam.
A Dutch team has already done the initial testing. Holland Innovation Team is planning a pilot study in a desert location. They don’t say where. They don’t say how they’re going to extract the water either. See below
But before you go. Consider. There’s a group of men parked outside of Heartbreak Hotel. Specifically Shell’s experimental in situ oil shale facility, Piceance Basin, Colorado. They climb up to their beds every night. Every night they toss and turn. In the morning they go out to a set of cool tools they’ve developed to extract oil from oil shale using steam injection. There’s several other processes that involve superheated air and others. See the list here. (As well for surface gypsum —concentrated solar might be appropriate.) Anyhow, they’re all revved up and ready to go but congress (specifcally a senator from colorado)is telling them they have to sit on their thumbs and think about it. (For that matter the BLM is holding up a lot of solar development.)
Someone might find these guys and say hey. While you wait. You can can use your cool tools on our gypsum. Funding should be easy.
The water from gypsum looks to be relatively expensive. But certainly it would be fraction of the cost of oil from oil shale since the oil shale requires 600+ degrees heat (vs 212F for gypsum) to cook out the oil and the deposits are usually 1000 feet down (vs at or near the surface for gypsum). And there’s no clean up or refining. For some desert valleys water from gypsum would be a fail safe water source.
Anyhow read the article below and consider.
Public release date: 11-Jun-2008
Water from rock, easier than blood from stone
Gypsum, a rocky mineral is abundant in desert regions where fresh water is usually in very short supply but oil and gas fields are common. Writing in International Journal of Global Environmental Issues, Peter van der Gaag of the Holland Innovation Team, in Rotterdam, The Netherlands, has hit on the idea of using the untapped energy from oil and gas flare-off to release the water locked in gypsum.
Fresh water resources are scarce and will be more so with the effects of global climate change. Finding alternative sources of water is an increasingly pressing issue for policy makers the world over. Gypsum, explains van der Gaag could be one such resource. He has discussed the technology with people in the Sahara who agree that the idea could help combat water shortages, improve irrigation, and even make some deserts fertile.
Chemically speaking, gypsum is calcium sulfate dihydrate, and has the chemical formula CaSO4.2H2O. In other words, for every unit of calcium sulfate in the mineral there are two water molecules, which means gypsum is 20% water by weight.
van der Gaag suggests that a large-scale, or macro, engineering project could be used to tap off this water from the vast deposits of gypsum found in desert regions, amounting to billions of cubic meters and representing trillions of liters of clean, drinking water.
The process would require energy, but this could be supplied using the energy from oil and gas fields that is usually wasted through flaring. Indeed, van der Gaag explains that it takes only moderate heating, compared with many chemical reactions, to temperatures of around 100 Celsius to liberate water from gypsum and turn the mineral residue into bassanite, the anhydrous form. “Such temperatures can be reached by small-scale solar power, or alternatively, the heat from flaring oil wells can be used,” he says. He adds that, “Dehydration under certain circumstances starts at 60 Celsius, goes faster at 85 Celsius, and faster still at 100 degrees. So in deserts – where there is abundant sunlight – it is very easy to do.”
van der Gaag points out that the dehydration of gypsum results in a material of much lower volume than the original mineral, so the very process of releasing water from the rock will cause local subsidence, which will then create a readymade reservoir for the water. Tests of the process itself have proved successful and the Holland Innovation Team is planning a pilot study in a desert location.
“The macro-engineering concept of dewatering gypsum deposits could solve the water shortage problem in many dry areas in the future, for drinking purposes as well as for drip irrigation,” concludes van der Gaag.
“Mining water from gypsum” in International Journal of Global Environmental Issues, 2008, 8, 274- 281
Public release date: 11-Jun-2008