Energy-efficient

Energy efficiency of the process. If the process requires a furnace or steam boiler to provide a hot utility, then any excessive use of the hot utility will produce excessive utility waste through excessive generation of CO2, NO, SO, particulates, etc. Improved heat recovery will reduce the overall demand for utilities and hence reduce utility waste. 

Cooling tower blowdown can be reduced by improving the energy efficiency of processes, thus reducing the thermal load on cooling towers. Alternatively, cooling water systems can be switched to air coolers, which eliminates the problem altogether. 

Reducing products of combustion from furnaces, steam boilers, and gas turbines by making the process more energy efficient through improved heat recovery. 

Increased energy efficiency. Increasing energy efficiency and the introduction of cogeneration reduce CO2 emissions. Remember that emissions should be viewed on a global basis, as discussed in Chap. 10. 

Increase energy efficiency of the process. Increasing the energy efficiency decreases the fuel burnt and hence decreases SO, emissions at the source. Again, the emissions should be viewed on a global basis. 

Chemical processes will in the future need to be designed as part of a sustainable industrial development which retains the capacity of ecosystems to support industrial activity and life. This book therefore places a high emphasis on waste minimization and energy efficiency in the context of good economic performance and good health and safety practices. 

In order to maintain high energy efficiency and ensure a long service life of the materials of construction in the combustion chamber, turbine and jet nozzle, a clean burning flame must be obtained that minimizes the heat exchange by radiation and limits the formation of carbon deposits. These qualities are determined by two procedures that determine respectively the smoke point and the luminometer index. 

We should therefore conclude that refining will witness a very important evolution, without revolution, but which will affect both the processes and procedures utilized, the objective being to produce clean products in a clean , energy-efficient manner. 

Homogeneous sonochemistry typically is not a very energy efficient process (although it can be mote efficient than photochemistry), whereas heterogeneous sonochemistry is several orders of magnitude better. Unlike photochemistry, whose energy inefficiency is inherent in the production of photons, ultrasound can be produced with neatly perfect efficiency from electric power. A primary limitation of sonochemistry remains the small fraction... 

During the late 1970s, concerns were raised about levels of airborne formaldehyde in buildings resulting primarily from constmction using composite panels bonded with urea—formaldehyde resins and combined with energy-efficient building practices which reduced air losses. 

Design Methods. Improvements ia the ability to predict multicomponent equilibrium and mass-transfer rate performance will allow significant improvements ia the design of new adsorption systems and ia the energy efficiency of existing systems. 

Eigure 6 enables a comparison to be made of kj a values in stirred bioreactors and bubble columns (51). It can be seen that bubble columns are at least as energy-efficient as stirred bioreactors in coalescing systems and considerably more so when coalescence is repressed at low specific power inputs (gas velocities). 

It is also interesting to use Figure 6 to make a comparison of different aeration devices on the basis of energy-efficiency. From equation 6 and assuming a constant driving force... 

From equation 23, it can be seen that the higher the power input per unit volume, the lower the oxygen transfer efficiency. Therefore, devices should be compared at equal transfer rates. AH devices become less energy efficient as rates of transfer increase (3). 

A survey of nonelectrolytic routes for CI2 production was conducted by Argonne National Laboratory the economics of these processes were examined in detail (76). One route identified as energy efficient and economically attractive is the conversion of waste NH Cl to CI2. 

The selection of a process can be complex, requiring carehil evaluation of the many variables for each appHcation. The hemihydrate process is energy efficient, but this may not be an overriding consideration when energy is readily available from an on-site sulfuric acid plant. The energy balance in the total on-site complex may be the determining factor. 

Natural gas is by far the preferred source of hydrogen. It has been cheap, and its use is more energy efficient than that of other hydrocarbons. The reforming process that is used to produce hydrogen from natural gas is highly developed, environmental controls are simple, and the capital investment is lower than that for any other method. Comparisons of the total energy consumption (fuel and synthesis gas), based on advanced technologies, have been discussed elsewhere (102). 

The principal producers of aluminum trifluoride in North America are Alcan, Alcoa, and AUiedSignal. It is also produced in other countries, eg, France, Mexico, Norway, Italy, Tunisia, and Japan. Total worldwide production of aluminum trifluoride in 1990 was 400,000 metric tons and the price was 1100/t. In 1993, because of excess recovery of fluorine values, use of energy efficient smelters, and the worldwide economic climate, the price was down to 750/t. 

Methane. As our most abundant hydrocarbon, methane offers an attractive source of raw material for organic chemicals (see Hydrocarbons). Successful commercial processes of the 1990s are all based on the intermediate conversion to synthesis gas. An alternative one-step oxidation is potentially very attractive on the basis of simplicity and greater energy efficiency. However, such processes are not yet commercially viable (100). 

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