Process equipment maintenance safety

Introduction Review and audit processes are used in the chemical process industry to evaluate, examine, and verify the design of process equipment, operating procedures, and management systems. These processes assure compliance with company standards and guidelines as well as government regulations. Reviews and audits can encompass the areas of process and personnel safety, environmental and industrial hygiene protection, quality assurance, maintenance procedures, and so on. 

Other information may also benefit the PHA. Standard operating procedures for processing equipment, safe work practices, maintenance or job safety analyses, emergency response plans could be appropriate review items for some PHAs depending upon the toll. 

Increased maintenance cost for process equipment due to safety requirements (for example, safety permits, cleaning and purging equipment, personal protective equipment, training, and restricted access to process areas). 

During the plant design the safety of process equipment is also recognized by layout. The objectives of layout are to minimize risk to personnel, to minimize escalation (both within the plant and to adjacent plants), and to ensure adequate emergency access. It is also essential to ensure adequate access for maintenance and operations. Plant layout is a crucial factor in the safety of a process plant because of e.g. segregation of different risks, containment of accidents and limitation of exposure. Safe plant layout is designed on the basis of design... 

This safety audit is used for identifying inputs and material flows, processes and intermediates, and final products - but with special attention paid to human-material/process/equipment interactions that could result in (a) sudden and accidental releases/spills, (b) mechanical failure-based injuries, and (c) physical injuries - cuts, abrasions, and so on, as well as ergonomic hazards. Additional sources of adverse effects/safety problem areas are records/ knowledge of in-plant accidents/near misses, equipment failures, customer complaints, inadequate secondary prevention/safety procedures and equipment (including components that can be rendered non-operable upon unanticipated events), and inadequacies in suppliers of material and equipment or maintenance services. 

Equipments handling supercritical fluids and liquefied gases present important hazards that must be taken into account both for equipment design and construction and for operation and maintenance. Safety considerations must influence any technical choice and operation and a detailed analysis of potential hazards must be specifically conducted for any case. In this paper, we would try to list the different classes of hazards and how to cope with them, so that both the process designer and the operator be informed. 

Cost-reduction projects are aimed at reducing the cost of production of an existing plant. The most common cost-reduction investments are for preventive maintenance, in which equipment is replaced, repaired, or cleaned after a planned interval and before the equipment deteriorates to the point where it could impact process performance or safety. Most preventive maintenance projects are small and are handled through the plant maintenance budget, but some can be very large, expensive projects requiring a major plant shutdown, for example, replacing the fired tubes in a main... 

As plants age there is a need for increased maintenance on the process equipment to ensure continued operability. To ensure safe and reliable operation, the maintenance practices used must follow suggested vendor recommendations or be defined internally to address technical and safety considerations. The continued operability of chemical agent stockpile incineration facilities is dependent in part on the effectiveness of the maintenance systems to proactively address obsolescence in their procedures and practices and to modify systems as required to process severely degraded stockpile items. 

As emphasized throughout this book, many different types of auxiliary equipment and secondary operations can be used to maximize overall processing plant productivity and efficiency. Their proper selection, use, and maintenance are as important as the selection of the processing machines (injection molder, extruder, etc.). The processor must determine what is needed, from upstream to downstream, based on what the equipment has to accomplish, what controls are required, ease of operation and maintenance, safety devices, energy requirements, compatibility with existing equipment, and so on. This chapter provides examples of this selection procedure and its importance in evaluating all the equipment required in a processing line. Details on all the equipment that is available can be obtained from plastics industry trade publications, usually compiled in an annual issue. These and other pertinent publications are included in the reference section (1-4, 33, 271-289). 

This paper focuses on how to model the deterioration of static pressurized process equipment to enable efficient inspection and maintenance planning. Such equipment tends to gradually deteriorate over time from erosion, corrosion, fatigue and other mechanisms, and at some point of time inspection, repair or replacement is expedient with respect to safety, production and costs. The deterioration of the equipment is influenced by many factors such as type of equipment, system design, operation and process service, material and environment. For hydrocarbon systems, the most critical deterioration mechanisms are corrosion due to CO2 and H2S, microbially influenced corrosion, sand erosion and external corrosion (DNV 2002). In general, CO2 is the most common factor causing corrosion in oil and gas system of low alloy steel (Singh et al. 2007). 

For process equipment, designers need to specify necessary safety features and the tests for meeting requirements. For process equipment, there should be fail-safe features. Fire protection, overpressure, excess heat, runaway reactions, dust control, exhaust ventilation, dangers of flammable liquids, leaks, sensing devices to report status are all examples of important safety features. Designers and purchasers need to consider access for setup, maintenance and cleaning. There may be a need for access by stairs, fixed ladders or platforms as part of large equipment. 

ANSI/ISA-84.00.01-2004 contains several references to the need to provide a manual shutdown backup for the logic solver. The main reference is clause 11.2.8, which states, Manual means (for example, emergency stop push button), independent of the logic solver, shall be provided to actuate the SIS final elements unless otherwise directed by the safety requirement specifications. This clause outlines a specific way a manual shutdown may be implemented, but allows the user to specify other ways to provide a manual shutdown. Manual shutdown can be initiated by the operator using the BPCS, remote or local pushbuttons and switches, or directly with process equipment, e.g., manual closure of valves. Manual shutdown capability should be provided for any SIS where maintenance bypasses are used to support online equipment repair, maintenance, and proof test. 

Process technology—the study and application of the scientific principles (math, physics, chemistry) associated with the operation (instruments, equipment, systems, troubleshooting) and maintenance (safety, quality) of the chemical processing industry. 

In 2009 I graduated from technical college with an Associate of Applied Science (AAS) degree in Process Technology. My course of studies included the operation and maintenance of a full-scale pilot plant, console operation, bench-top operation, process equipment and systems instrumentation, chemistry, math, and physics. Additional topics of study included safety, quality control, troubleshooting, and the academic core. 

Chapter 3, Process Equipment and Procedures, covers safety considerations in the design, installation, operation, and maintenance of selected process equipment and auxiliary systems. 

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