Redesign

Alternative fuels fall into two general categories. The first class consists of fuels that are made from sources other than cmde oil but that have properties the same as or similar to conventional motor fuels. In this category are fuels made from coal and shale (see Fuels, synthetic). In the second category are fuels that are different from gasoline and diesel fuel and which require redesigned or modified engines. These include methanol (see Alcohol fuels), compressed natural gas (CNG), and Hquefted petroleum gas (LPG). 

MTS Systems Corp. Box 24012 Minneapolis, Minn. 55424 Publishes Standards Cross-Keference Eist that includes standards issued by one agency but adopted and renumbered or redesignated by another agency, compiled and cross-referenced to aid in their location and identification. 

Modification of Equipment. (/) Install equipment that produces minimal or no waste. 2) Modify equipment to enhance recovery or recycling options. (I) Redesign equipment or production lines to produce less waste. (4) Improve operating efficiency of equipment. (5) Maintain strict preventive maintenance program. 

Improved and redesigned rotors of modem compressors save considerable power. The ethylene fractionator and the propylene refrigeration condensers can be replaced with extended surface tube bundles instead of conventional tube bundles. 

Redesign piping layout, using fewer elbows and laterals for tees, and have five or more straight pipe diameters before suction flange. 

Process. synthesis. Concept development, construction of flowsheets for new processes, and redesign or modification of existing process flowsheets. 

Waste Reduction Processes can be redesigned to reduce the amount of waste generated. For example, transfer hnes between processes can be Blown clear pneumaticaUy to drive liquid into the Batch mix tank. 

Changes may come too late, possibly requiring redesign of the process. 

Cavitation Formation of transient voids or vacuum bubbles in a liquid stream passing over a surface is called cavitation. This is often encountered arouna propellers, rudders, and struts and in pumps. When these bubbles collapse on a metal surface, there is a severe impact or explosive effec t that can cause considerable mechanical damage, and corrosion can be greatly accelerated because of the destruction of protective films. Redesign or a more resistant metal is generally required to avoid this problem. 

Applied. Generally, adequate reduction of applied stresses involves equipment redesign. 

Of the various approaches to reducing cavitation damage, redesign of equipment is probably the most successful. The following have proven useful ... 

Running unbal- Redesign feed distributor anced—vibration. different bowl speed (usually slower) due to uneven feeding effective vibration monitor/shutdown device Adjust feed rate to get uniform distribution ... 

Vent system Reduce feed rate or redesign vent system not balanced with inlet, or undersized. ACGIH 1986 CCPS G-22 CCPS G-23 CCPS G-29... 

Relocate/redesign the gauges so that operator can read them easily... 

Similarly, when the machine is required to operate at leading p.f.s. the field system has to be redesigned, as the normal field system, which is designed for lagging p.f.s, will be inelfeclive, as discussed below. 

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