Carbon dioxide reserves

Rayon is unique among the mass produced man-made fibers because it is the only one to use a natural polymer (cellulose) directly. Polyesters, nylons, polyolefins, and acryflcs all come indirectly from vegetation they come from the polymerization of monomers obtained from reserves of fossil fuels, which in turn were formed by the incomplete biodegradation of vegetation that grew millions of years ago. The extraction of these nonrenewable reserves and the resulting return to the atmosphere of the carbon dioxide from which they were made is one of the most important environmental issues of current times. CeUulosic fibers therefore have much to recommend them provided that the processes used to make them have minimal environmental impact. 

Figure 9-82E. -in. packing data for system carbon dioxide-sodium hydroxide, gas rate constant. Reproduced by permission of the American Institute of Chemical Engineers, Leva, M., AI.Ch.E. Jour., V. 1, No. 2 (1955) p. 224 all rights reserved. 

Figure 12-14J. Compressibility chart for low-pressure carbon dioxide. (Used by permission Form 3519 D (1981), 1960. Ingersoll-Rand Company. All rights reserved.)...

It was expected that an eggshell thickness of scale would form, but that it would be relatively soft and easily removed (despite normally containing some silicate and sulfate). However, a disadvantage of this method of internal control was that the carbonate degraded to form carbon dioxide, and at higher pressures the rate of breakdown was so great that the necessary carbonate reserve required to prevent sulfate scale often could not be maintained. (Never mind the danger to the steam and condensate lines from the production of carbon dioxide and ultimately carbonic acid.)... 

Chemical processes should be designed as part of a sustainable industrial activity that retains the capacity of ecosystems to support both life and industrial activity into the future. Sustainable industrial activity must meet the needs of the present, without compromising the needs of future generations. For chemical process design, this means that processes should use raw materials as efficiently as is economic and practicable, both to prevent the production of waste that can be environmentally harmful and to preserve the reserves of raw materials as much as possible. Processes should use as little energy as is economic and practicable, both to prevent the build-up of carbon dioxide in the atmosphere from burning fossil fuels and to preserve the reserves of fossil fuels. Water must also be consumed in... 

Carbon Dioxide The C02 of the sea and its reserves in some carbonates equilibrates with the atmosphere and is one source of green house gases... 

On a human time scale, the input of fossil fuel carbon dioxide is not sudden. The rate is expected to increase for several hundred years and then to decrease again as reserves are exhausted, as shown in Table 5-1 (Broecker and Peng, 1982, p. 553). The program being developed here can be used to simulate the response of the ocean and atmosphere to a gradual input of carbon dioxide. 

Fat is the most important energy reserve in the human body. The energy is realized by conversion of the fats to fatty acids and glycerol and their oxidation to carbon dioxide and water. Let s see the consequences of these catabolic conversions. 

Fuel. Lipids are an important source of energy in the diet. In quantitative terms, they represent the principal energy reserve in animals. Neutral fats in particular are stored in specialized cells, known as adipocytes. Fatty acids are released from these again as needed, and these are then oxidized in the mitochondria to form water and carbon dioxide, with oxygen being consumed. This process also gives rise to reduced coenzymes, which are used for ATP production in the respiratory chain (see p. 140). 

Research and Technology Roadmap to Address the Barriers to Carbon Dioxide Injection into Deep Coal Seams. The Roadmap will identify areas where research, development or demonstration is required for the technology to be used in Australia as a means of generating low greenhouse gas emission power from Australia s bountiful coal reserves. 

In the underground experiments, scientists inject carbon dioxide into spaces deep in the Earth. Some of these underground spaces are caves or old mines others are empty holes that once held oil or natural gas. Oil companies have practiced these storage methods for decades because they are relatively inexpensive and easy, and can also enrich existing oil reserves. But so far, no company or government has officially adopted this method for long-term carbon storage. 

Worldwide, the amount of energy available from coal is estimated to be about ten times greater than the amount available from all petroleum and natural gas reserves combined. Coal is also the filthiest fossil fuel because it contains large amounts of such impurities as sulfur, toxic heavy metals, and radioactive isotopes. Burning coal is therefore one of the quickest ways to introduce a variety of pollutants into the air. More than half of the sulfur dioxide and about 30 percent of the nitrogen oxides released into the atmosphere by humans come from the combustion of coal. As with other fossil fuels, the combustion of coal also produces large amounts of carbon dioxide. 

Both hot and cold processes are employed, although the hot process, which takes place at or above 212°F (100°C) is usually reserved for boiler feed-water applications, as it produces water of lower hardness levels and usually a lower silica content as well. Also, less lime is needed, as the carbon dioxide it would normally react with is driven off at the higher temperatures. Sometimes caustic soda (sodium hydroxide) is used in place of soda, depending on the alkalinity of the water and the chemical costs however, irrespective of the process or chemicals used, the major precipi-tants are always calcium carbonate and magnesium hydroxide. 

Figure 8.6 The difference between selectivities calculated from pure gas measurements and selectivities measured with gas mixtures can be large. Data of Lee et al. [13] for carbon dioxide/methane with cellulose acetate films. Reprinted from S.Y. Lee, B.S. Minhas and M.D. Donohue, Effect of Gas Composition and Pressure on Permeation through Cellulose Acetate Membranes, in New Membrane Materials and Processes for Separation, K.K. Sirkar and D.R. Lloyd (eds), AIChE Symposium Series Number 261, Vol. 84, p. 93 (1988). Reproduced with permission of the American Institute of Chemical Engineers. Copyright 1988 AIChE. All rights reserved...

---