Cost modes

The potential of biomass to substitute for petroleum is examined in terms of resource availability and cost, conversion technology, and conversion and end-use costs. The most energy-efficient and least costly mode of utilization of wood is direct burning, followed by gasification, and, last, liquefaction. 

Urea Formation Is a Complex and Costly Mode of Ammonia Detoxification... 

Styrene-containing block copolymers are commercially very important materials. Over a billion pounds of these resins are produced annually. They have found many uses, including reinforcement of plastics and asphalt, adhesives, and compatibilizers for polymer blends, and they are directly fabricated into articles. Most styrene-containing block copolymers are manufactured using anionic polymerization chemistry. However, anionic polymerization is one of the more costly polymerization chemistries because of the stringent requirements for monomer and solvent purity. It would be preferred, from an economic cost perspective, to have the capability to utilize free radical chemistry to make block polymers because it is the lowest cost mode of polymerization. The main reasons for the low cost of FR chemistry are that minimal monomer purification is required and it can be carried out in continuous bulk polymerization processes. 

As the chemical industry grows in size, it will find it is able to meet increasingly the volume criteria for pipeline transportation, and it will be utilizing this low cost mode in increasing instances for raw materials, intermediates, and finished products. 

The burning question becomes Is the maximal efficient operation mode also the minimal cost mode The answer is not simply yes or no but with a necessary and sufficient condition to be satisfied. 

Supply chains also use responsive transportation to centralize inventories and operate with fewer facilities. For example, Amazon relies on package carriers and the postal system to deliver customer orders from centralized warehouses. McMaster-Carr uses ground transportation and package carriers to provide next-day delivery of a wide variety of MRO products to about 90 percent of U.S. businesses from five distribution centers. The location of its distribution centers along with an effective transportation network allows McMaster to be very responsive while using a low-cost mode of transportation. 

The operations group will develop general operating and maintenance objectives for the facilities which will address product quality, costs, safety and environmental issues. At a more detailed level, the mode of operations and maintenance tor a particular project will be specified in the field development plan. Both specifications will be discussed in this section, which will focus on the input of the production operations and maintenance departments to a field development plan. The management of the field during the producing period is discussed in Section 14.0. 

The service provided by maintenance engineering was traditionally that of repairing equipment items when they failed. This is no longer the case, and a maintenance department is now pro-active rather than reactive in its approach. Maintenance of equipment items will be an important consideration in the FDP, because the mode and cost of maintaining equipment plays an important part in the facilities design and in the mode of operation. 

A suitable maintenance strategy should be developed for equipment by considering the criticality and failure mode, and then applying a mixture of the forms of maintenance described above. In particular, the long-term cost of maintenance of an item of equipment should be estimated over the whole life of the project and combined with its capital cost to select both the type of equipment and form of maintenance which gives the best full lifecycle cost on a discounted basis), while of course meeting the technical, safety and environmental specifications. 

Failure Mode and Effects Analysis. The system design activity usually emphasizes the attainment of performance objectives in a timely and cost-efficient fashion. The failure mode and effects analysis (FMEA) procedure considers the system from a failure point of view to determine how the product might fail. The terms design failure mode and effects analysis (DFMEA) and failure mode effects and criticaUty analysis (EMECA) also are used. This EMEA technique is used to identify and eliminate potential failure modes early in the design cycle, and its success is well documented (3,4). 

Use of traveling wave tube (TWT) amplifiers at power levels of hundreds of watts has been proposed (54) for power appHcations, at least when the heating chamber is well shielded. The potential advantage is an improved uniformity of heating when a broad band of frequency is used, ie, excitation of many modes. Disadvantages are high cost and lower (<50%) efficiency of the TWT. 

These mixing systems offer high flexibility because they can be operated in batch, semibatch, or continuous modes. Adequate mixing is a prerequisite for the success of chemical processes in terms of rninirnizing investment and operating costs. In addition, chemical reactions with... 

Process Hazards Analysis. Analysis of processes for unrecogni2ed or inadequately controUed ha2ards (see Hazard analysis and risk assessment) is required by OSHA (36). The principal methods of analysis, in an approximate ascending order of intensity, are what-if checklist failure modes and effects ha2ard and operabiHty (HAZOP) and fault-tree analysis. Other complementary methods include human error prediction and cost/benefit analysis. The HAZOP method is the most popular as of 1995 because it can be used to identify ha2ards, pinpoint their causes and consequences, and disclose the need for protective systems. Fault-tree analysis is the method to be used if a quantitative evaluation of operational safety is needed to justify the implementation of process improvements. 

Ammonia is usually transported for long distances by barge, pipeline, and rail, and for short distances by tmck Eactors that govern the type of carrier used in anhydrous ammonia transportation systems are distance, location of plant site in relation to consuming area, availabihty of transportation equipment, and relative cost of available carriers. Typical costs (83) of pipeline, barge, and rail modes for long distance transport are 0.0153, 0.0161, and 0.0215 per ton per kilometer, respectively, for distances of about 1600 km. Short distance tmck transportation costs (83) are much higher. Costs are typically 0.0365/(t km) for distances on the order of 160 km. 

As of this writing (1996), 354 MWe of privately funded, paraboHc-trough electric generating capacity was operating in California. These trough systems operate in a hybrid mode, using natural gas. Collectively they accounted for more than 90% of worldwide solar electric capacity. The cost of these systems fell steadily from 0.24/kWh for the first 14-MW system to an estimated 0.08/kWh for the 80-MW plant installed in 1989 (5). 

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