Cost sheet maintenance

Maintenance costs influence the bottom line of every balance sheet. As a result, maintenance managers can improve the entire faciHty by helping make sure that the planning and design of new constmction and renovation projects takes place with maintenance in mind (1). 

The plant engineer and his maintenance manager will establish whoever carries out the work, basic strategy, programming and procedures. Inspection checklists and record sheets are necessary for systematic location of critical elements/potential defects and setting out frequencies of inspection. Computers and work processors are an obvious aid to effective maintenance management. Inspection-based preventive methods are demonstrably cost effective. 

The SELECTOR Technology is characterized by its simple flow sheet and low-operating pressure. This results in low capital and maintenance expenses and product cost, and high plant availability. Mild reaction conditions minimize byproduct formation. Low byproduct formation also contributes to higher process efficiencies and product qualities. 

Such sketches develop into flow sheets, which are more elaborate diagrammatic representations of the equipment, the sequence of operations, and the expected performance of a proposed plant or the actual performance of an already operating one. For clarity and to meet the needs of the various persons engaged in design, cost estimating, purchasing, fabrication, operation, maintenance, and management, several different kinds of flowsheets are necessary. Four of the main kinds will be described and illustrated. 

The production cost break-down itemization includes, in addition to the above indicated cost of raw material and cost of financing, the cost of energy for the process, labor, maintenance and repairs, insurance, taxes and royalities. These costs have been variously listed in the study reports. Estimates range from approximately 15 dollars per ton to over 20 dollars per ton of finished product. It is not the purpose here to present a detailed balance sheet or income statement. There has been far too little operating time of the Stillwater plant to establish the long-term costs yet. The replacement of machine parts has been a... 

After the process information has been integrated into one or more flow sheets, the economic aspects of the design are next considered. This involves (1) an estimate of the types and sizes of equipment and materials, buildings, ground area, and utility facilities (2) a determination of what the process will cost based on physical facilities and construction charges (3) a cost estimate of utilities consumption (steam, electricity, water, fuel), labor and supervision personnel requirements, maintenance and repairs, raw materials, and finance charges (interest, taxes, insurance, medical benefits, etc.). 

On the typical sheet cutting machine these maintenance and wear items would cost approximately 2.50/h. There are also miscellaneous repairs that may be incurred. These repairs average approximately 1.80/h. 

Cathodic protection is used widely for the protection of submerged steel in waterfront structures. It also can provide considerable benefit in the intertidal zone and can even reduce the usually high corrosion rate experienced at the boundary between the intertidal zone and the splash and spray zone. Cathodic protection also is used to prevent corrosion of the soil side of steel in marine structures such as sheet steel bulkheads. Cathodic protection also is effective in the control of the corrosion of reinforcing steel in concrete in all exposure zones in waterfiont structures. Particularly for impressed current systems, it is important to select materials for the cathodic protection system components such as rectifiers and junction boxes with consideration of the environment to which they will be exposed. When considering cathodic protection, periodic inspection and maintenance is required for proper system operation. The costs for inspection and maintenance must be considered in the overall cost of cathodic protection. While there are no specific standards for cathodic protection of piers and docks, information in NACE RP0176 (Corrosion Control of Fixed Offshore Platforms Associated with Petroleum Production) and NACE RP-0187 (Design Considerations for Corrosion Control of Reinforcing Steel in Concrete) contain information that is applicable to marine piers and docks. 

The fifth and final step is experience and analysis. Every 6 months there should be technical, financial, and organizational reporting. The technical reports should emanate from the technician work sheets, history files, and recommendations on job plans. The financial and organizational reports should be based on maintenance cost per unit, fault code analysis, plant availability, and related factors. 

Depending on their dimensions, it is possible to distinguish hollow-fiber membranes (diameter < 0.5 mm), capillary membranes (0.5 mm < diameter < 5 mm), and tubular membranes (diameter > 5 mm) [34]. The preparation of hollow-fiber membranes through PI is more complex, with respect to flat sheet, due to the higher number of parameters involved. However, hollow-fiber modules are usually preferred, because they ensure space savings, more productivity, and reduction of costs, which is also connected to maintenance, as these modules can be backflushed [35]. 

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