Engineering Uses

Under certain conditions of temperature and pressure, and in the presence of free water, hydrocarbon gases can form hydrates, which are a solid formed by the combination of water molecules and the methane, ethane, propane or butane. Hydrates look like compacted snow, and can form blockages in pipelines and other vessels. Process engineers use correlation techniques and process simulation to predict the possibility of hydrate formation, and prevent its formation by either drying the gas or adding a chemical (such as tri-ethylene glycol), or a combination of both. This is further discussed in SectionlO.1. 

Many U.S. and foreign automobile manufacturers are developing a fuel flexible vehicle in the 1990s. Ford has developed FFVs for 5-L engines used... 

Cetane Improvers. Compared to dedicated alcohol engines, fewer hardware changes need to be made to heavy-duty engines using cetane... 

Four buses converted to ethanol started operation in 1979 and the engine used was an OM 352, 6 cylinder, direct injection engine rated at 96,200 watt (129 hp). The ignition improver was -hexyl nitrate [20633-11-8] which was later changed to triethylene glycol dinitrate [111-22-8] (TEGDN). 

Resihency provides another opportunity for the mbber functioning as a cushion between stainless steel loop clamps and fuel—hydraulic fluid lines in aircraft. Pratt and Whitney E-lOO military jet engine use (12) provides vibration damping without the clamp abraiding the tube surfaces in normal service as well as at temperatures down to —55°C. 

One hquid in this class intended for aircraft engine use is described in military specification MIL-L-87100 for operation from +15 to 300°C. Limitations of this class of synthetics are pour points of +5°C and higher, relatively poor lubricity, and high cost of 265/L ( 1000 + /gal) (44). Polyphenyl ether greases are available with good radiation resistance for appHcations in the temperature range of +5 to 288°C. 

Babbitt appHcation methods vary greatiy. Most high performance bearings in automotive engines use plated lead babbitt of 10% tin and about 3% copper as covered by SAE 19 and SAE 190 specifications (6). 

A.STM B656, Standard Guide for Autocatalytic Nickel—Phosphorus Deposition on Metals for Engineering Uses American Society for Testing and Materials, Philadelphia, Pa., 1991. 

Total Pressure is the pressure that would occur if the fluid were brought to rest in a reversible adiabatic process. Many texts and engineers use the words total and stagnation to describe the flow characteristics interchangeably. To be accurate, the stagnation pressure is the pressure that would occur if the fluid were brought to rest adia-baticaUy or diabatically. 

M. S. Phadke, Quality engineering using robust design, Prentice-Flail, Englewood Cliffs, NJ, 1989, P.292. 

Operators with previous experience in similar tolls teamed with engineers using the process safety information can identify the specific procedures needed within each subcategoiy. Whenever possible, tiy to use experience from duplicate tolls or similar processes. 

Phadke, M. D. 1989 Quality Engineering Using Robust Design. Englewood Cliffs, NJ Prentice-Hall. 

Mobile sources therefore consist of many different types of vehicles, powered by engines using different cycles, fueled by a variety of products, and emitting varying amounts of both simple and complex pollutants. Table 6-4 includes the more common mobile sources. 

Control of diesel-powered vehicles is parhally accomplished by fuel modification to obtain reduced sulfur content and cleaner burning and by proper tuning of the engine using restricted fuel settings to prevent overfueling. 

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