Carbon dioxide LOCAT process

A large portion of the carbon dioxide recovered is used at or near the location where it is generated as an ingredient in a further processing step. In this case, the gaseous form is most often used. Low temperature Hquid and soHd carbon dioxide are used for refrigeration. Where the producer and the consumer are distant, carbon dioxide maybe Hquifted to reduce transportation cost and revaporized at the point of consumption. 

The nature of these processes requires the supply of clean compressed air to blow the hot melt located within the blow mold. Other gases can be used, such as carbon dioxide, to speed up cooling of the blown melt in the mold. The gas usually requires at least a... 

SACHEM Inc., located in Cleburne, Texas, is a producer of high-purity bulk chemicals for companies that have high-purity requirements in their chemical processing. As stated in Workplace Scene 1.2, one of their products is tetramethylammonium hydroxide (TMAH), which is sold to semiconductor industries. The analysis of TMAH for trace anions such as chloride, nitrate, nitrite, and carbonate is critical for SACHEM s quality control laboratory. If these ions are present on the integrated circuit boards manufactured by one of their semiconductor customers, they may cause corrosion severe enough to affect the functionality and performance of the electronic devices in which the circuit boards are used. In SACHEM s quality control laboratory, ion chromatography procedures have been developed to measure the anion concentrations in TMAH. Because the concentration levels are trace levels, a clean room environment, like that described in Workplace Scene 1.2, is used. A special procedure for carbonate analysis is required so that the absorption of carbon dioxide from the atmosphere can be minimized. 

There are already several large industrial plants in operation which process hops with carbon dioxide. These plants are located in Germany, Great Britain, Australia, and in the US. 

The oxygen formed clearly comes from H20 and not from C02, because photosynthesis in the presence of water labeled with lgO produces oxygen labeled with 180, whereas carbon dioxide labeled with 180 does not give oxygen labeled with 180. Notice that the oxidation of the water produces two electrons, and that the formation of NADPH from NADP requires two electrons. These reactions occur at different locations within the chloroplasts and in the process of transferring electrons from the water oxidation site to the NADP reduction site, adenosine diphosphate (ADP) is converted to adenosine triphosphate (ATP see Section 15-5F for discussion of the importance of such phosphorylations). Thus electron transport between the two photoprocesses is coupled to phosphorylation. This process is called photophosphorylation (Figure 20-7). 

Depending on source, geographic location, and the extent of extraction, the acid gas content of fuel gases often exceeds pipeline specifications. Certain natural gases and landfill gases can contain up to 50% carbon dioxide. Bulk removal of both carbon dioxide and hydrogen sulfide from such sources, i.e., the process of sweetening, not only improves the fuel value of the gas, but also helps reduce corrosion of pipelines and transmission equipment. Membranes are suitable for this application especially where the scale is relatively small and the economics favor scalable membrane systems. 

The ultimate disposal of hazardous organic pollutants is emerging as a priority in the search for innovative treatment technologies. Ultimate disposal is the mineralization of pollutant compounds to inorganic constituents such as water and carbon dioxide. Conventional treatment processes have often focused on removal of a pollutant from a particular location, without concern for its ultimate disposition. Examples include landfilling, deep-well injection, or vapor vacuum extraction with collection on carbon filters. Eventually, the hazardous compound treated with these techniques must be dealt with again. 

First the amino group was converted to a hydroxy group via a diazonium ion (Section 17.10). The benzene ring was reduced with hydrogen and a catalyst to produce cyclohexanol. Oxidation with potassium dichromate (Section 10.14) gave cyclohexanone. The bonds between the carbonyl carbon and both a-carbons were then cleaved by a series of reactions not covered in this book. The carbon of the carbonyl group was converted to carbon dioxide in this process. One-half of the original radioactivity was found in the carbon dioxide, and the other one-half was found in the other product, 1,5-pentanediamine. Additional experiments showed that the 14C in the diamine product was located at C-l or C-5. 

A scratch pad can be very useful for a spread-sheet user. A scratch pad is an area (e.g., columns to the right of the main spread sheet) set aside for doing side calculations of parameters or constants for the main spread sheet, writing comments, locating macros, and other uses. A scratch pad would be useful in this example if the user needed mass balances for a particular product flow rate rather than a specified feed rate as just illustrated. The problem has been solved for a carbon dioxide feed rate of 100 mol/h as shown above, but suppose it is desired to know the feed rate required to produce 880 mol/h of methanol product. The problem might intentionally be solved first for a specified feed rate, because it is often more convenient to write the mass-balance equations for known process feed rates rather than known product rates. 

In the contiguous United States, the main emphasis is on miscible CO2 flooding. Carbon dioxide is relatively inexpensive since it has no value as a fuel and is available in large amounts from natural deposits or as a waste product of industrial processes. Table I shows major natural deposits of CO2, their approximate amounts, and their locations with respect to oil fields ( 1). With (or even without) partial recycling of CO2, there is no foreseeable shortage of this injection fluid. 

---