Foreword

Engineers like to think of their discipline as a rigorous application of scientific and mathematical principles to the problem of creating a useful object. To a certain extent, this is an appropriate description of the tools of engineering those techniques that we use to translate a concept in the mind of the designer into a physical object. But, where does that mental image of the object to be built come from At its heart, engineering is intuitive, and an art form. The engineer designer's...

A6 Cooling System Control Failure Failure Scenario B

For batch reactors, the most commonly installed control system is temperature control for heating and cooling. Temperature control is necessary to achieve proper reaction conditions for good conversions to minimize side product formation, and in many cases, to prevent the occurrence of product deterioration and runaway reactions. In this reaction, the potential for runaway reactions has been determined to be low, but it is known that product deterioration (tarring) can occur if the reaction...

323 Batch Pharmaceutical Reactor Accident

While two operators were charging fiber drums containing a penicillin powder into a reactor containing a mixture of acetone and methanol, an explosion occurred at the reactor manhole. The two operators were blown back by the force of the explosion, and were covered with solvent-wet powder. The incident was initiated by the ignition of solvent vapors, which resulted in a dust explosion of the dry powder. The solvent liquid mixture in the reactor did not ignite. Tests on the polyethylene liner...

52past Incidents

This section describes past incidents that illustrate hazard scenarios involving mass transfer equipment. 5.2. I Distillation Column Critical Concentration In 1969 an explosion occurred in a butadiene recovery unit at Texas City. The location of the center of the explosion was found to be the lower tray section of the butadiene refining (final purification) column. The butadiene unit recovered byproduct butadiene from a crude C4 stream. The overhead of the refining column was a high-purity...

A8 Loss Of Sealing Fluid To Reactor Agitator Mechanical Seal Failure Scenario D

The loss of sealing fluid to the reactor agitator mechanical seal can result in large emissions of flammable hydrogen and solvents into the building, and possibly outside, which could deflagrate if the vapor cloud encountered an energy source of sufficient strength. Since hydrogen has a very low MIE (0.016 mj) it can very easily be ignited. Appreciable equipment damage and injury or fatality could result if a deflagration occurred inside the building. The agitator mechanical seal fluid is...

A4 Selection Of Design Bases For Safety Systems

This section uses the systematic risk-based technique for selecting the design bases for process safety systems discussed in chapter 2. Use of the technique imposes discipline on the thought process, yet allows for flexibility in application. The design bases selection technique is comprised of a number of analysis and testing steps, detailed graphically in a decision tree (see Exhibit 2.2 in Chapter 2). In this example, each of the selection steps (1-9) will be discussed generally, then, steps...

115 References

Lessons from Disaster. Houston, TX Gulf Publishing Company. Kletz, T. A. 1994. Learning from Accidents. Oxford Butterworth-Heinemann Ltd. Liptak, B.G. 1985. Instrument Engineers Handbook Process Control. Radnor, PA Chilton Books. MCA 1966. Case Histories of Accidents in the Chemical Industry. MCA 1966 Vol.2, Case History 1068. NFPA 8501 1992. Standard fir Single Burner Boiler Operation. National Fire Prevention Association, Quincy, MA. NFPA 8502 1995. Standard for the...

44 Discussion

4.4.1 Use of Potential Design Solutions Table To arrive at the optimal design solution for a given application, use Table 4 in conjunction with the design basis selection methodology presented in Chapter 2. Use of the design solutions presented in the table should be combined with sound engineering judgment and consideration of all relevant factors. Reactors may be grouped into three main types batch, semi-batch, and continuous. In a batch reactor, all the reactants and catalyst (if one is...

45 References

Guidelines for Chemical Reactivity Evaluation and Application to Process Design. New York American Institute of Chemical Engineers. Kletz,T. A. 1990. Critical Aspects of Safety and Loss Prevention, p. 265. London Butterworth & Co. Ltd. Kletz, T. A. 1994. What Went Wrong Case Histories ofProcess Plant Disasters. 3ded.,pp. 309-310. Houston, TX Gulf Publishing Co. Lees, F. P. 1996. Loss Prevention in the Process Industries. 2d ed. Woburn, MA Butterworth Inc. Quinn, M. E., Weir, E....

Contents

Introduction 1.1 Objectives 1.2 Scope 1.3 Background 1.4 Applicability and Audience 1.5 Organization of This Book 1.6 References Suggested Additional Reading 2. Technique for Selecting the Design Bases for Process Safety Systems 2.1 Risk-Based Design Decisions 2.2 The Concept of Risk 2.3 Selection of Design Bases for Safety Systems 2.3.1 Step 1 Identify Failure Scenarios 2.3.2 Step 2 Estimate the Consequences 2.3.3 Step 3 Determine Tolerability of...

Table 8 Failure Scenarios For Fluid Transfer Equipment

Failure of control or closure of downstream block valve, or failure to remove blind, or plugged oudet which deadheads pump compressor resulting in possible overpressure and or excessive temperature Minimum flow recirculation line to ensure a minimum flow through the machine (flow controlled by orifice) Downstream piping specified to withstand deadhead pressure High temperature shutdown interlock High pressure shutdown interlock Low flow or power shutdown interlock Minimum flow recirculation...

27 References

Advisory Committee on Major Hazards. 1976. First Report. London Her Majesty's Stationary Office. API RP 2003 1991. Protection Against Ignition Rising Out of Static, Lightning, and Stray Currents. Washington, DC American Petroleum Institute. Bellomo, P. J., and R.P. Stickles. 1995. Select Design Bases for Emergency Relief and Other Process Safety Systems Based on Risk. Paper presented at International Symposium on Runaway Reaction and Relief Design, August 1995, Boston, Massachusetts. Bendixen,...

85 References

Guide for Pressure Relieving andDepressuring Systems. Washington, DC American Petroleum Institute Grossel, S.S. 1990. Highly Toxic Liquids Moving Them Around the Plant. Part 1. Chemical Engineering, 97(4). Newby, T. and Forth, D. 1991. Glandless Pumps and Valves A Technical Update. The Institution of Chemical Engineers Symposium Series. 124 Institution of Chemical Engineers. Bloch, H. P., Cameron, J. A., James, Jr., R., Swearinger, J. S., and Weightman, M. E. 1982. Compressors...

125 References

Operating Atmospheric Vent Collection Headers Using Methane Gas Enrichment, Process Safety Progress, 15(4). CCPS 1993. Guidelines for Engineering Design for Process Safety. Center for Chemical Process Safety. New York American Institute of Chemical Engineers. Howard, W.B. 1991. Use Precaution in Selection, Installation and Operation of Flame Arresters, Chemical Engineering Progress, April. IChemE 1987. Hazard Workshop Module 012 Safer Piping Volume I. Rugby, Warwickshire,...

25 I Four Categories of Design Solutions

Before proceeding with examples illustrating the application of the technique for selection of safety system design bases, a review of generic design solutions for minimizing risk is appropriate. Safety system designs fall into one of four categories. INHERENTLY SAFER design solutions eliminate or mitigate the hazard by using materials and process conditions that are less hazardous. For an extensive discussion of the concept of inherently safer chemical processes, see CCPS 1996. Examples of...

62past Incidents

This section provides several case histories of incidents involving failure of heat transfer equipment to reinforce the need for the safe design practices presented in this chapter. 6.2.I Ethylene Oxide Redistillation Column Explosion In March 1991, an Ethylene Oxide (EO) redistillation column exploded at a Seadrift, Texas chemical facility. The explosion was caused by energetic decomposition of essentially pure EO vapor and liquid mist inside the column. A set of extraordinary circumstances...

Design Solutions For Process Equipment Failures

AMERICAN INSTITUTE OF CHEMICAL ENGINEERS 345 East 47th Street New York, New York 10017 American Institute of Chemical Engineers All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise without the prior permission of the copyright owner. Library of Congress Cataloging-in Publication Data Guidelines for design solutions for process equipment failures,...

84discussion

8.4.1 Use of Potential Design Solutions Table To arrive at the optimal design solution for a given application, use Table 8 in conjunction with the design basis selection methodology presented in Chapter 2. Use of the design solutions presented in the table should be combined with sound engineering judgment and consideration of all relevant factors. This section contains additional information on selected design solutions. The information is organized and cross-referenced by the Operational...

42past Incidents

Reactors are a major source of serious process safety incidents. Several case histories are presented to reinforce the need for safe design and operating practices for reactors. On July 10, 1976 an incident occurred at a chemical plant in Seveso, Italy, which had far-reaching effects on the process safety regulations of many countries, especially in Europe. An atmospheric reactor containing an uncompleted batch of 2,4,5-trichlorophenol (TCP) was left for the weekend. Its temperature was 158 C,...

261 Locking Open a Valve A Simple Design Case

Locking open a valve is a commonly used procedural design solution, applied to a wide range of potential operational and safety problems. At first glance, locking open a valve may not even seem like a design decision. Such a decision seems more an act of common sense 1 someone identifies a safety problem arising from the inadvertent closing of a valve 2 the valve does not get used that often so, the obvious solution is to 3 lock open the valve. For process facilities operating under a strict...

32I Storage Tank Autopolymerization Incident

Plant operating problems had resulted in the production of a tank approximately 32,000 lb of glacial acrylic acid GAA which did not meet specifica tions due to high water content. The material was held in storage until it was loaded into a tank wagon, where it was to be kept until the GAA could be reworked. The operator's logbook specified that warm water 25 C maximum was to be used to keep the GAA from freezing freezing point 13 C . The outside temperature was 5-10 C at the time. A standard...

102 Past Incidents

Several case histories involving failures in solids handling and processing equipment are presented to reinforce the need for safe design and operating practices presented in this chapter. 10.2.I Silicon Grinder Fire and Explosion A chemical plant which processed silicon-based chemicals experienced a fire and explosion in a grinder. Raw silicon was received in 1- or 2-inch lumps which had to be ground to a 200-mesh powder before being used in chemical processes. The air-conveyed silicon powder...