© 2012 Delmar, Cengage Learning Chapter 25 Welding Metallurgy.
© 2012 Delmar, Cengage Learning Chapter 11 Engineering Controls.
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Transcript of © 2012 Delmar, Cengage Learning Chapter 11 Engineering Controls.
© 2012 Delmar, Cengage Learning
Chapter 11Engineering Controls
© 2012 Delmar, Cengage Learning
Risk Evaluation
• Hazardous materials• Chemical process• Physical operations• Equipment design• Plant location and layout• Operator practices and training
© 2012 Delmar, Cengage Learning
Hazardous Materials Evaluation
• A detailed analysis of all the properties of the materials handled, stored, and processed in the plant:
• Quantities• Physical properties• Toxicity• Stability hazards• Corrosiveness• Impurities
© 2012 Delmar, Cengage Learning
Chemical Process Evaluation
• Analyzes the hazardous properties of reactants, which are products that might be formed under certain conditions, and the environmental effects of those products.
© 2012 Delmar, Cengage Learning
Physical Operations Evaluations
• Dusting• Heat transfer• Pressure• Vaporization• Spaying• Mixing• Separation• Generation
© 2012 Delmar, Cengage Learning
Equipment Design Evaluation
• Equipment systems are designed so that the failure of one or more devices will not result in a disaster.
© 2012 Delmar, Cengage Learning
Plant Location and Layout Evaluation
Key elements include:• Drainage and runoff control• Climatic conditions• Effects of uncontrolled release• Community capability and emergency response• Plant accessibility• Available utilities• Gate security• Hazardous unit placement• Spacing of equipment
© 2012 Delmar, Cengage Learning
Operator Practices and Training Evaluation
• Operational failures have been identified as the most frequent cause of industrial disasters.
© 2012 Delmar, Cengage Learning
Design and Operation of Plants for Safety
• There must be adequate spacing between process equipment, specific storage, and loading facilities.
• Evaluate and limit the storage of hazardous material.
• Evaluate the use of open structures and will recommend new designs for total storage containment.
© 2012 Delmar, Cengage Learning
Figure 11-1 Triangular Equipment Placement
© 2012 Delmar, Cengage Learning
Alarms and Indicators
The most effective tool used by process technicians in the operation of a large chemical facility are alarms and indicators.
© 2012 Delmar, Cengage Learning
Fire Alarms and Detection Systems
Automatic fire alarm systems come in three types:
• Fixed-temperature type• Rate-of-rise type• Nuclear detector type
© 2012 Delmar, Cengage Learning
Redundant Alarm and Shutdown Devices
Operating a large chemical complex requires the use of redundant systems that provide emergency warning and shutdown protection. Redundancy is a process that uses two or more devices to shut down a system.
© 2012 Delmar, Cengage Learning
Interlocks and Automatic Shutdown Devices
• An interlock is a device that will prevent an operational action unless a specific condition has been satisfied
• Software• Hardwire
• A permissive is a special type of interlock that contains a set of conditions that must be satisfied before a piece of equipment can be started.
© 2012 Delmar, Cengage Learning
Process Containment and Upset Control
• There are a number of elements in controlling process containment and in the design of upset control:
• Reduction in hazardous material storage inventory
• Storage of liquefied gases and the conditions under which these should be stored
• Plan for a design that provides total containment
© 2012 Delmar, Cengage Learning
Figure 11-3 Traditional and Nontraditional Diking Systems (Totally Self-Contained).
© 2012 Delmar, Cengage Learning
Closed System/Closed-Loop Sampling
Closed systems/closed-loop sampling is a procedure where a bypass loop is installed that allow a small part of the system to be diverted from the main flow.
© 2012 Delmar, Cengage Learning
Figure 11-4 Closed-Loop Sampling System
© 2012 Delmar, Cengage Learning
Floating Roof Tank and Ventilation Systems
• Floating roof storage tanks are used for storing materials at atmospheric pressure.
• Ventilation systems are usually designed to protect process technicians from organic vapors, harmful additive dusts, and fumes.
© 2012 Delmar, Cengage Learning
Figure 11-5 Floating Tank Designs
© 2012 Delmar, Cengage Learning
Effluent Control and waste Water Treatment
New technicians are typically assigned to this area in order to train on a variety of complex systems.
© 2012 Delmar, Cengage Learning
Figure 11-6 Clarifier
© 2012 Delmar, Cengage Learning
Figure 11-7 Settling Basin
© 2012 Delmar, Cengage Learning
Noise Abatement
• Noise abatement is an engineering procedure designed to reduce or limit noise through the use of modern technology.
© 2012 Delmar, Cengage Learning
Flares
• Flares are used to burn waste gases and control pressure generated by process upsets.
© 2012 Delmar, Cengage LearningFigure 11-8 Flare System
© 2012 Delmar, Cengage Learning
Pressure Relief Devices
• Safety valves for gases• Relief valves for liquids• Rupture discs for both
© 2012 Delmar, Cengage Learning
Figure 11-9 Pressure Relief Devices