We all are keenly aware of the ongoing battle globally and in the US House of Representatives and Senate, in terms of passing certain CO2-related rules and regulations surrounding the American Clean Energy and Security Act of 2009.
Both sides pro and con, are hotly debating the subject and of course, much of large industry is hoping for little passage in terms of CO2 emissions control, much of which is driven by the recession; as well as overall economic impact, even in good times.
Around 15% of all US CO2 sources for the merchant markets are derived from natural underground wells; or natural gas separation by-product off MEA, or a similar solvent.
Moreover, many more times this volume of a relatively pure CO2, at least potentially, could be or is now sourced from underground wells, coal gasification, or MEA concentration – which go to the oil patch in terms of an agent used in Enhanced Oil Recovery (EOR).
In terms of the hazardous side of carbon dioxide and methane, such gases are of course unhealthy and deadly when inhaled for extended periods of time.
For example, taking CO2 in this context, earlier this year on average about 387 ppm of CO2 was found in the atmosphere - not considering examples near or surrounding earthquakes, landslides, or volcanically active zones.
During such events, the consequences can be dire. In the case of carbon dioxide, up to 5,000 ppm (or 0.5%) in concentration have been used for respiratory stimulation, when applied in proper hospital settings. On the other hand, when CO2 is over 1% or 10,000 ppm, drowsiness will occur.
At 7-10%, dizziness, visual dysfunction and unconsciousness will occur, within a range of between minutes and two hours.
One specific story recently reported in the UK-based Observer, spoke of potential African-located episodes on a rather tragic scale.
Over two million people living on the banks of Lake Kivu in Central Africa (between Congo and Rwanda) are at risk of being asphyxiated by primarily carbon dioxide and methane, which are now being trapped in layers at the bottom of the lake by the intense pressure of the water.
The CO2 and methane has bubbled into the lake from volcanic vents and seem to be, at least, temporarily trapped in strata some 80 metres below the lake’s surface. It is feared that certain geologic events, such as a quake or mudslide could unleash these gases into the atmosphere.
Some records show a 10% rise in CO2 volume and a 15% rise in CH4 (methane) in Lake Kivu, between the years 1974 and 2004. At the same time, plankton fossils on the lake’s bed have revealed several massive events of biological extinctions in Lake Kivu over thousands of years.
It is impossible to say that such an explosive and deadly event is imminent – however it is possible.
The positive side of the CH4 concentration in Lake Kivu has produced a new natural gas source, for domestic and industrial energy demands in this region.
A previous example of the hidden dangers of CO2 lurking beneath a lake surface occurred in 1986, at Lake Nyos in Cameroon, West Africa. The waters were saturated with carbon dioxide and it is believed that a major disturbance, probably a landslide, caused these gases to be unleashed into the atmosphere.
Due to the relatively heavy nature of CO2, the gas settled down in the valleys that lead from the crater-lake.
This event, per some estimates, asphyxiated some 1,700 people; all due to the CO2 cloud hanging low to the ground. This example of CO2 pouring out of the lake, could be readily compared with a shaken-up bottle of beer or soft drink - while opening up the cap and watching the contents pour out.
Such examples are typical of regions in the world that are hotspots for seismic and volcanic events. Should large-scale pipelines explode, often holding CO2 at a pressure up to 2000 psig and typically found in large EOR projects, this could be devastating - depending upon the location of a population base.
In any event, CO2 trapped in abandoned salt mines, oil & gas fields, and like structures are finding a strong opposition due to government agencies citing safety concerns; surrounded by possible leakage, geological events, and unknown factors, which have never truly been tested. This means of sequestration is unproven and dangerous.
As for methane, much is a product of bacterial decomposition of organic matter in an anaerobic environment. Methane is combustible in the air when in concentrations from 5-15%, while CH4 or methane can be a volatile killer. Methane is odorless and cannot be detected by the physical senses.
Solving the problem?
The sequestration of CO2 via chemical manufacturing, and pumping into deep aquifer formations below the rock and soil, are probably the most viable means of solving some of the quest to absolutely remove CO2 from the atmosphere, in a form which will not return.
In any event, we are challenged by an ever-growing level of CO2 being sent to the atmosphere every second of the day. Only one third of total global CO2 emissions is naturally taken in by the world’s oceans – driven by the ongoing motion of the tides, and other activity within the natural oceanic activity; and plant life.
No matter how you look at the carbon dioxide subject, we are in excess on a daily emissions level with the already heavily burdened ocean sink, as well as other natural sinks such as the rainforests, ever-declining.
It seems that CO2 may well be one of mankind’s greatest challenges ahead.
Sam A. Rushing is president of Advanced Cryogenics, Ltd., based in South Florida, now celebrating 20 years of success as a full range supplier of CO2 consulting expertise.