Plant costs reliability

Availability and reliability have a very major impact on the plant economy. Reliability is essential in that when the power is needed it must be there. When the power is not available it must be generated or purchased, and can be very costly in the operation of a plant. Planned outages are scheduled for non-peak periods. Peak periods is when the majority of the income is generated as usually there are various tiers of pricing depending on the demand. Many power purchase agreements have clauses, which contain capacity payments, thus making plant availability critical in the economics of the plant. 

While reliable data are not readily available on feedstock use by type, e.g., natural gas, oil, naphtha, and coal, a look at world r rves of natural gas, oil, and coal by region indicates that natural gas will be the dominant feedstock. Coal use will decline because of environmental aspects and high plant costs. Oil and naphtha viD continue to be used as feedstocks primarily in those regions or areas that do not have natural as reserves and are unable to receive natural gas by pipeline. Review of reserve data covering all feedstocks Indicates no shortage of feedstock material through the year 2000. 

From a load carrying requirement the rack is to meet a maximum deflection and relate it to the cost of fabrication (material, labor, amortization costs of equipment including tools, and the usual plant costs of overhead, etc.). If the designer does not have this type experience it is best done with the assistance of a reliable fabricator who potentially will make the product. 

It is recommended that a filter screen be used ahead of and in conjunction with filters of this type. Continuous self-cleaning filters of this kind are considered to be one of the most reliable types of bulk water filter available, with low plant costs and high clarification efficiencies. A full scale array of moving bed filters is shown in Figure 4.6. 

The use of electrochemical protection in the chemical industry started about 20 years ago, which is somewhat recent, compared with its use for buried pipelines 40 years ago. Adoption was slow because the internal protection has to be tailored to the individual plant, which is not the case with the external protection of buried objects. Interest in internal protection came from the increasing need for greater safety for operating plants, increased demands for corrosion resistance, and larger plant components. While questions of its economy cannot generally be answered (see Section 22.6), the costs of electrochemical protection are generally less than the cost of equivalent and reliable coatings or corrosion-resistant materials. 

Improving the economics of gas plant design, construction, and operations is essential to ensure the approval of future de-bottlenecking, capacity expansion, and new projects. The economics include not only capital investment, life cycle operations, and maintenance costs, but also the monetary equivalents of safety, reliability, and availability. 

Attached to the expanders, the compressors provide an additional 60 psig without energy cost outlay. Further compression ultimately raises gas pressure to 34 bar. MESA estimates that the arrangement at its Satanta plant saves 45 kW (60 hp) while reliably handling the daily production of natural gas. 

Type of Plant Capital Cost /kW Heat Rate Btu/kWh kJ/kWh Net Efficiency Variable Operation Maintenance ( /MWh) Fixed Operation Maintenance ( /MWh) Availability Reliability Time from Planning to Completion Months... 

Maintenance practices are being combined more and more with operational practices to ensure that plants have the highest reliability with maximum efficiency. This has led to the importance of performance condition monitoring as a major tool in the operation and maintenance of a plant. Life cycle costs, rightly so, now drive the entire purchasing cycle and thus the... 

The US EPA explored UV light for small scale water treatment plants and found it compared unfavorably with chlorine due to 1) higher costs, 2) lower reliability, and 3) lack of a residual disinfectant. 

The confluence of sharply rising Operations and Maintenance (O M) costs. NRC requested Individual Plant Examinations (IPEs) and increased personal computer capabilities gave rise to the R R Workstation. Its uses and maintains-current PSA models and databases for individual plants to perform O M planning and scheduling, and uses the PSA in IPE models to identify plant design, procedure and operational vulnerabilities. The Risk and Reliability Workstation Alliance was organized by EPRI to support the R R Workshop in order to achieve O M cost reduction, plant productivity and safety enhancement through risk-based, user-friendly, windowed software louls (Table 3.6 8). The Alliance, initiated in 1992, includes 25 U.S. utilities and four international partners from Spain, France, Korea, and Mexico. SAIC is the prime contractor for the R R Workstation, with participation of five other PSA vendors. 

The Chemical Process Industry (CPI) uses various quantitative and qualitative techniques to assess the reliability and risk of process equipment, process systems, and chemical manufacturing operations. These techniques identify the interactions of equipment, systems, and persons that have potentially undesirable consequences. In the case of reliability analyses, the undesirable consequences (e.g., plant shutdown, excessive downtime, or production of off-specification product) are those incidents which reduce system profitability through loss of production and increased maintenance costs. In the case of risk analyses, the primary concerns are human injuries, environmental impacts, and system damage caused by occurrence of fires, explosions, toxic material releases, and related hazards. Quantification of risk in terms of the severity of the consequences and the likelihood of occurrence provides the manager of the system with an important decisionmaking tool. By using the results of a quantitative risk analysis, we are better able to answer such questions as, Which of several candidate systems poses the least risk Are risk reduction modifications necessary and What modifications would be most effective in reducing risk ... 

This report addresses ammonia plant shutdowns over the listed time period in 40 countries. It provides a basis for comparing plant performance area by area leading to better control of reliability efforts while reducing maintenance and unplanned shutdown costs. Data are presented for shutdowns due to power, equipment, instrumentation, feedstock and product inventory control. 

About 2.5 million tons (2.3 million tonnes) of coal arc burned daily in U.S. power plants. This is equivalent to roughly 21,000 railcars in transit, so it is apparent that coorditiatiiig production and cotistimp-tioii is no easy task. Accidents, rail strikes, natural disasters (e.g., floods that take out bridges and rail lines) and severe weather (e.g., deep river freezes that halt barge traffic) can all severely disrupt deliveries for utility customers dependent on a reliable coal supply for base load plants. Nonetheless, to reduce costs U.S. utilities have significantly reduced typical inventory levels over time. Wliereas a coal inventory of ninety days of supply was once typical, inventories now frequently run in the range of thirty to forty-five days. 

Where small and/or single contaminant effluents are encountered, packaged treatment plants may be acceptable. Consideration should, however, be given to capital cost, payback period, reliability of equipment, maintenance, plant-life expectancy and contaminant-removal efficiencies. 

The main consideration in the selection of a compressor plant is the production of an adequate supply of compressed air at the lowest cost consistent with reliable service. The installation of a compressed air system, as with all forms of power transmission, calls for capital investment with consequent operating and maintenance costs. The information on which the selection of plant is based should be as accurate as possible. Important factors to be considered are the following. 

For routine monitoring of machine vibration, however, this approach is not cost effective. The time required to manually isolate each of the frequency components and transient events contained in the waveform is prohibitive. However, time-domain data has a definite use in a total plant predictive maintenance or reliability improvement program. 

A survey of 500 plants that have implemented predictive maintenance methods indicates substantial improvements in reliability, availability and operating costs. The successful programs included in the survey include a cross-section of industries and provide an overview of the types of improvements that can be expected. Based on the survey results, major improvements can be achieved in maintenance costs, unscheduled machine failures, repair downtime, spare parts inventory, and both direct and in-direct overtime premiums. In addition, the survey indicated a dramatic improvement in machine life, production, operator safety, product quality and overall profitability. 

The purpose of predictive maintenance is to minimize unscheduled equipment failures, maintenance costs and lost production. It is also intended to improve the production efficiency and product quality in the plant. This is accomplished by regular monitoring of the mechanical condition, machine and process efficiencies and other parameters that define the operating condition of the plant. Using the data acquired from critical plant equipment, incipient problems are identified and corrective actions taken to improve the reliability, availability and productivity of the plant. 

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