Welcome to the Cquestrate blog

  • Conversations about Cquestrate

    Posted on August 6th, 2008 by Chris Unitt in General

    Cquestrate launched just over two weeks ago and we’ve already seen a great level of discussion on the website.  Some of the comments and contributions have started to move the project forward in encouraging ways.

    However, discussions about Cquestrate aren’t restricted to this website and it has been fascinating to read, and contribute to, what has been going on elsewhere.  Here’s a very small sample:

    When I come across anything useful I use del.ici.ous to ‘tag’ the page.  Links to these tagged pages are collected automatically on our links page for all to see.

    Unfortunately, it can be tricky to find all of these conversations.  However, it’s important we do our best to follow them  - we don’t want to miss out on some potentially valuable information.

    If you are part of a community that has discussed Cquestrate or if you’ve blogged about the project, please let us know in the comments below.

    One person has left a comment so far, why not join in the discussion?

     

  • Why bother heating up the limestone?

    Posted on July 24th, 2008 by Tim Kruger in General

    It seems like heating up limestone until it breaks down into lime is a lot of hard work to get alkalinity into the ocean. Why not put the limestone directly in the water?

    Well, the problem is that limestone is very insoluble, which explains the continuing existence of the White Cliffs of Dover. It is possible to get limestone to dissolve in water, but you have to grind it to an extremely small size and even then it dissolves very slowly. To enhance the ability of the oceans to act as a carbon sink, you need the reaction to take place in the top 100m of the ocean, as this is the layer where most of the mixing with the atmosphere takes place. Even small particles of limestone sink like stones (which is after all what they are) and little of the required reaction will occur in the right place. To grind limestone down into a fine enough powder is both expensive both in terms of energy and in terms of the equipment required. Also the energy that is required is mechanical energy which is much more expensive than heat energy.

    There are other sources of alkalinity that can be added. Kheshgi identified mineral deposits of soda ash (Na2CO3) as one such source, but noted that using the world’s entire recoverable resources of soda ash would offset just a single year of CO2 emissions. Caldera and Rau have put forward an idea that reacts CO2 from the flue gases of power stations with limestone and then puts the resulting calcium bicarbonate solution into the sea - this has a lot of merit - it addresses CO2 before it is emitted, but does not remove CO2 from the air after it has been emitted, as the process described on this website does.

    All these methods can be used - the questions are how can they be done in an environmentally beneficial way and how can they be done economically? These are the key questions we are trying to answer - and with your help we will

    Nobody has left a comment so far, why not join in the discussion?

     

  • Getting ready for launch

    Posted on July 17th, 2008 by Chris Unitt in General

    With a couple of days left before the website launches we’re just finalising content, producing explanatory videos and making sure that everything is working properly.

    We’ve had to move very quickly to ensure that everything is in place as soon as possible. With the first phase of the website almost complete it’ll soon be a case of making sure that word goes out to the people who can help further this project.

    The scope is so large that we need a wide spread of expertise - if you, or anyone you know anyone, can help in any way then we look forward to your input. Have a look at the questions we need to answer and leave your comments on the relevant pages.

    Nobody has left a comment so far, why not join in the discussion?

     

  • The Idea

    Posted on July 14th, 2008 by Jamie Huskisson in Uncategorized

    This is a brief description of the idea. If you prefer we also have a detailed description and a slideshow presentation on the process for you to see.

    The idea works like this:

    • First, you heat limestone to a very high temperature, until it breaks down into lime and carbon dioxide.
    • Then you put the lime into the sea, where it reacts with carbon dioxide dissolved in the seawater.

    The important point is that when you put lime into seawater it absorbs almost twice as much carbon dioxide as is produced by the breaking down of the limestone in the first place.

    This has the effect of reducing the amount of carbon dioxide in the atmosphere. It also helps to prevent ocean acidification, another problem caused by the increase in the amount of carbon dioxide in the atmosphere.

    If done on a large enough scale it would be possible to reduce carbon dioxide levels back to what they were before the Industrial Revolution.

    The first step of the process – breaking down limestone into lime and carbon dioxide – seems counterintuitive as it uses a lot of energy and actually produces carbon dioxide. But this carbon dioxide can either be safely stored away or used to help grow crops in very dry areas. You can find out more about this here.

    One of the questions I often get asked is: if this is so simple why hasn’t it been done before? The idea has been around for a number of years. It was first suggested by Haroon Kheshgi in 1995, but it was considered uneconomic as the process uses a large amount of energy. What we are interested in doing is using stranded energy to drive the process.

    Stranded energy is energy that is remotely located, so it is not economically viable to exploit. For example, in a desert there is plenty of energy available, but it would cost too much to transfer the energy to where anyone wants it, so it never gets used. So, paradoxically, in a desert energy is abundant and cheap, but worthless. This process can use that stranded energy.

    We couldn’t have got this far without the help of a large number of people who have been extremely generous with their time and expertise. We are developing this project in an open source way, so, if you are interested to help, please get involved.

    2 people have left a comment so far, why not join in the discussion?