Glossary

Administrative Controls See Design Solutions. Autoignition Temperature The autoignition temperature of a substance, whether solid, liquid, or gaseous, is the minimum temperature required to initiate or cause self-sustained combustion, in air, with no other source of ignition. Basic Event An event in a fault tree that represents the lowest level of resolution in the model such that no further development is necessary (e.g., equipment item failure, human failure, or external event)....

72 Past Incidents

This section presents three case histories involving fires and explosions (deflagrations) to reinforce the need for safe design and operating practices for dryers and drying systems. 7.2.1 Drying of Compound Fertilizers A fire and explosion occurred in a dryer handling a blended fertilizer that contained single and triple super-phosphates and a mixture of The blend was prone to self-sustained decompositions, and began decomposing while passing through the dryer. When the temperature of the...

101 Introduction

This chapter presents potential failure mechanisms for solids handling and processing equipment, and suggests design alternatives for reducing the risks associated with such failures. The types of equipment covered in this chapter include Pneumatic conveying systems Comminution equipment (mills, grinders, crushers) Sieving (screening) equipment Solids feeders (rotary valves, screw feeders, etc.) Solids enlargement equipment (extruders, briquetters, etc.) Spray granulators and coaters This...

51introduction

This chapter presents potential failure mechanisms for mass transfer equipment and suggests design alternatives for reducing the risks associated with such failures. The types of mass transfer operations covered in this chapter include This chapter presents only those failure modes that are unique to mass transfer equipment. Many of the generic failure modes presented in Chapter 3 may also apply to vessels used for mass transfer. Mass transfer equipment failure may also result from disturbances...

References

Sizing, Selection, and Installation of Pressure-Relieving Devices in Refineries. Part 1-Sizing and Selection. Washington, DC American Petroleum Institute. API RP 752 1995. Management of Hazards Associated with Locations of Process Plant. 1st Edition. Washington, DC American Petroleum Institute. ASME 1995. Boiler and Pressure Vessel Code. Section VIII, Division 1. New York American Society of Mechanical Engineers. CCPS 1989. Guidelines for Process Equipment Reliability Data....

A 10 Documentation

It is critical to provide accurate, detailed, and readily available documentation of all PSS design bases, so that assumptions can be easily verified, and critical safety components be identified. In the case of existing plants, such as the one in this example, these documents may not be readily available, and it may be necessary to contact equipment vendors or make new calculations (e.g., for sizing of relief devices). This documentation is particularly important when one element of the...

A3 Pss Discussion For Batch Reactors

A.3.I Vessel Design and Primary Containment Batch chemical reactors can be expensive because of their materials of construction requirements due to service involving corrosive reactants, catalysts, or solvents. Many are fabricated of stainless steel, glass-lined carbon steel, or materials such as Hastelloy, titanium, etc. due to service involving corrosive reactants, catalysts, or solvents. In addition, in current practice batch reactors are highly instrumented and automated (run by...

15organization Of This Book

This book begins with this brief introductory chapter, followed by Chapter 2, which presents a practical and systematic technique for selecting the design bases for process safety systems. A series of equipment chapters follows, presenting known failure scenarios for the specific equipment in question alongside associated design solutions. Finally, the book concludes with an appendix comprised of two worked examples. In summary, this book has four parts Chapter 2. Technique for Selecting...

121introduction

This chapter presents potential failure mechanisms for piping and piping components and suggests design alternatives for reducing the risks associated with such failures. The types of piping and piping components covered in this chapter include Piping (metallic, nonmetallic, lined, jacketed, double walled) Components (flanges, expansion joints, gaskets, bolts, etc.) This chapter presents only those failure modes that are unique to piping and piping components. Some of the generic failure...

232Step 2 Estimate the Consequences

In this step, estimate the consequences of the failure scenarios identified in step 1. In general terms, these can relate to quality, safety, health, and environmental impacts. For these Guidelines, consequences of interest include fires, explosions, toxic material releases, and major equipment damage. Engineers may, in some cases, uncover potential consequences by direct observation, engineering judgment or use of qualitative consequence criteria. In other cases the use of quantitative...

14applicability And Audience

The history of process safety related incidents suggests that engineers have lessons to learn about the most standard process equipment and components, such as storage tanks, pumps, and piping systems. Accordingly, these guidelines apply to standard process equipment and components and their known, related failure scenarios for both new and existing process facilities. Given the broad range of standard process equipment covered, this book should apply to a wide variety of system designs. While...

A7 External Fire Failure Scenario C

External fire is always a possibility when flammable liquids are being handled. A pool fire under the reactor will impinge on wetted and unwetted vessel surfaces, boiling the liquid contained in the reactor and, eventually, resulting in overpressurization of the vessel. If the overpressure is not relieved in time, rupture of the reactor may occur due to both thermal and pressure overstress. To provide overpressure protection for the external fire failure scenario, the reactor was provided with...

35 References

Welded Steel Tanks for Oil Storage. Washington, DC American Petroleum Institute. CCPS 1993. Guidelines for Engineering Design for Process Safety. Center for Chemical Process Safety, New York American Institute for Chemical Engineers. Drake, E.M., Geist, J. M., and Smith, K. A. 1973. Preventing LNG Rollover. Hydrocarbon Processing. Drogaris, G. 1993. Major Accident Reporting System Lessons Learned from Accidents Notified. Amsterdam Elsevier Science Publishers, B.V. Santayana,...

Worked Examples

This appendix contains two example problems which are intended to illustrate the use of the techniques and thought processes given in Chapters 2-12 of this book. Each example will use specific process situations to show how to use Chapter 2 to determine the process safety system (PSS) design basis, identify the design parameters which have the strongest impact on that basis, and assist in the selection of alternative inherendy safer, passive, active and procedural design solutions. These...

14 Discussion

11.4.1 Use of Potential Design Solutions Table To arrive at the optimal design solution for a given application, use Table 11 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...

Ii Introduction

This chapter presents potential failure mechanisms for fired equipment and suggests design alternatives for reducing the risks associated with such failures. The types of fired equipment covered in this chapter include This chapter presents only those failure modes that are unique to fired equipment. Some of the generic failure scenarios pertaining to vessels and heat transfer equipment may also be applicable to fired equipment. Con-sequendy, this chapter should be used in conjunction with...

112 Past Incidents

This section describes several case histories of incidents involving failure of fired equipment to reinforce the need for the safe design practices presented in this chapter. A safety shut-off valve on the gas supply to a burner remained open after the unit was shut down. There was no indicator to show that the valve was open or closed. On start-up, the operator opened the main valve on the gas supply to the burner before lighting the pilot burner. When he tried to light the burner, an...

Example Problem Batch Chemical Reactor

This example problem is based on an existing industrial batch reaction system. It illustrates a batch reactor where a quinone-type organic compound is hydro-genated to a hydroquinone. The reaction product is an intermediate for a pharmaceutical. Reactors require a detailed hazard analysis before the proper Process Safety System (PSS) can be determined due to the complexity of the operation (heat and mass transfer and chemical reaction), as well as the different kinds and severity of events that...

A I System Description

The batch reactor and associated equipment are shown in Exhibit Al, along with the material balance, and equipment data (sizes, dimensions, materials of construction, etc.). HYDROGEHATOR AGITATOR 2000 GAL TURBINE IMPELLER 78 00. x 93 T-T 125 RPM SH U_- 35 PSIO fV 350TF 31 SS JACKET 200 PSK < 35CF I 97 SO. FT. . 10 00 x 8 -0 LONG TUBES SHELL CS TUBES 31 SS > SOLVENTS AZEOMIXTURE * WASH FROM CATALYST > CATALYST SLURRY ' FROM HEAD TANK i SOLVENT AZEOMIXTURE. ' FROM SURGE TANK t QUINONE...

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...