The CO2 necessary for the production of methanol can be obtained from various emissions and, eventually, from the CO2 content of the atmosphere. Presently, worldwide, more than 20 billion tonnes of CO2 related to human activities are released into the atmosphere every year. Globally, CO2 emissions from electricity generation, industries, the transportation sector and heating or cooling of buildings are further increasing. They all contribute to the increase in CO2 levels in the atmosphere, from 270 ppm before the beginning of the industrial era to 370 ppm today. The resulting greenhouse effect could have a detrimental effect on the Earth's global climate and our ecological systems. For the coming decades, fossil fuels will foreseeably continue to provide the largest share of humanity's energy needs. The Kyoto agreement, although not yet approved by all countries, limits the CO2 emissions considerably. To reduce CO2 emissions, mitigation technologies must be developed and enforced. In this respect, more energy-efficient technologies and conservation can help, but this will not be sufficient to stop the global increase of CO2 emissions. In order to make a significant reduction in emissions, the recovery of CO2 from fossil fuel-burning sources will be necessary. CO2 can be obtained most readily from concentrated sources such as flue gases from fossil fuel-burning power plants, containing typically between 10-15% CO2 by volume. Many industrial exhausts, including those from cement, iron, steel and alu minum factories, also contain considerable concentrations of CO2. The recovery of CO2, though not yet employed on a large scale, is a well-known procedure, with the separation of CO2 being carried out with either liquid-phase absorbents or selective membranes.
Because they are large and concentrated sources of CO2, most proposed methods for CO2 recovery and disposal are currently focused on power plants and heavy industries. For such sources, on-site capture of CO2 offers the most sensible and cost-effective approach. On the other hand, more than half of the CO2 emissions are the result of small distributed sources such as home and office heating, and most importantly the transportation sector. Whilst collecting CO2 from vehicles onboard may be technically possible, it would be economically prohibitive. The CO2 storage system to be added to the vehicle would also be a difficult problem. Moreover, CO2 once collected, would have to be transported to a sequestration or recycling site, requiring the construction of a massive and expensive infrastructure. Capturing CO2 onboard airplanes is even less feasible, because of the added weight involved. In homes and offices, producing limited amounts of CO2, the collection and transportation of CO2 would also require an extensive and costly infrastructure. While these dispersed CO2 emissions can probably presently not be addressed, they represent a preponderant part of the global CO2 emissions and their importance can not be ignored in the long term.
Was this article helpful?
Your Alternative Fuel Solution for Saving Money, Reducing Oil Dependency, and Helping the Planet. Ethanol is an alternative to gasoline. The use of ethanol has been demonstrated to reduce greenhouse emissions slightly as compared to gasoline. Through this ebook, you are going to learn what you will need to know why choosing an alternative fuel may benefit you and your future.