Emergency Relief System Design Research Articles

Remembering Dr. Hans Fauske

Process Safety ProgressVolume 41, Issue 3 p. 602-602 LETTER TO THE EDITOR Remembering Dr. Hans Fauske Dilip K. Das, Corresponding Author Dilip K. Das dilipkdas@gmail.com Emergency Relief System Design and Process Engineering, Design and Safety, LLC, Kansas City, Missouri, USA Correspondence Dilip K. Das, Emergency Relief System Design and Process Engineering, Design and Safety, LLC, 4701 NE Shady Lane Drive, Kansas City, MO 64119, USA. Email: dilipkdas@gmail.comSearch for more papers by this author Dilip K. Das, Corresponding Author Dilip K. Das dilipkdas@gmail.com Emergency Relief System Design and Process Engineering, Design and Safety, LLC, Kansas City, Missouri, USA Correspondence Dilip K. Das, Emergency Relief System Design and Process Engineering, Design and Safety, LLC, 4701 NE Shady Lane Drive, Kansas City, MO 64119, USA. Email: dilipkdas@gmail.comSearch for more papers by this author First published: 06 July 2022 https://doi.org/10.1002/prs.12400Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume41, Issue3September 2022Pages 602-602 RelatedInformation

Modeling of the venting of an untempered system under runaway conditions

The prediction of the consequences of a runaway reaction in terms of temperature and pressure evolution in a reactor requires the knowledge of the reaction kinetics, thermodynamics and fluid dynamics inside the vessel during venting. Such phenomena and their interaction are complex and yet to be fully understood, especially reactions where the pressure generation is totally or partially due to the production of permanent gases (gassy or hybrid systems). Moreover, these phenomena cannot be easily determined by laboratory scale experiments. In this paper, a dynamic model developed to simulate the behavior of an untempered reacting mixture during venting is presented. The model provides the temperature, pressure and mass inventory profiles before and during venting. A sensitivity study of the model was performed. This modeling work provides some insight regarding the interpretation of the data obtained from untempered system venting experiments. The outcome of this work contribute to improving the design of emergency relief systems for hybrid and gassy systems, where significant progress is still to be made in the experimental and modeling areas.

Beyond the Phi factor: Correction of experimental data for vaporization in tempered reactions for pressure‐relief system design

Design of emergency relief systems to accommodate runaway reactions often requires using bench‐scale adiabatic calorimeters to evaluate thermokinetic data of a full‐scale reactor. However, the well‐known method to correct bench‐scale experimental data for “thermal inertia”—the Phi factor—does not consider the effect of vaporization on thermokinetic data. Calorimeter volumetric fill ratio is an important parameter directly relating to the vaporization effect and is discussed in this article. For a 60% fill ratio, a case study of an aqueous reaction system shows that the measured reaction heat would be 7% less than the actual value for a reaction with a heat release of 800 J/g, 5% less than the actual value with a heat release of 600 J/g, and 2% less than the actual value with a heat release of 300 J/g. The temperature rise rate is even more sensitive to the fill ratio. A high fill ratio is desirable, to get more‐accurate temperature rise data for a tempered exothermic reaction. A low fill ratio requires a significant Phi correction and could also give a misleading thermokinetic interpretation of a plant‐scale reactor. Applying the same fill ratio of a plant‐scale reactor to tests in an adiabatic calorimeter—to get thermokinetic data for emergency relief sizing—is recommended. © 2014 American Institute of Chemical Engineers Process Saf Prog 34: 130–136, 2015

The Pressure Relief System Design for Industrial Reactors

A quick and simple approach for reactor—emergency relief system design—for runaway chemical reactions is presented. A cookbook for system sizing with all main characteristic dimensions and parameters is shown on one realistic example from process industry. System design was done based on existing theories, standards, and correlations obtained from the literature, which were implemented for presented case. A simple and effective method for emergency relief system is shown, which may serve as an example for similar systems design. Obtained results may contribute to better understanding of blow down system frequently used in industrial plants, for increasing safety, decreasing explosion damage, and alleviating the ecological problems together with environmental pollution in case of industrial accidents.

Calorimetric studies and lessons on fires and explosions of a chemical plant producing CHP and DCPO

Cumene hydroperoxide (CHP) has been used in producing phenol, dicumyl peroxide (DCPO) and as an initiator for synthesizing acrylonitrile–butadiene–styrene (ABS) resin by copolymerization in Taiwan. Four incidents of fire and explosion induced by thermal runaway reactions were occurred in a same plant producing CHP, DCPO and bis-(tert-butylperoxy isopropyl) benzene peroxide (BIBP). The fourth fire and explosion occurred in the CHP reactor that resulted in a catastrophic damage in reaction region and even spread throughout storage area. Descriptions on the occurrences of these incidents were assessed by the features of processes, reaction schemes and unexpected side reactions. Calorimetric data on thermokinetics and pressure were used for explaining the practical consequences or which the worst cases encountered in this kind of plant. Acceptable risk associated with emergency relief system design is vital for a plant producing organic peroxide. These basic data for designing an inherently safer plant can be conducted from adiabatic calorimetry. An encouraging deduction has been drawn here, these incidents may be avoided by the implementation of API RP 520, API RP 521, DIERS technology, OSHA 1910.119 and AIChE's CCPS recommended PSM elements.

Education materials for universities and industry

The Safety and Chemical Engineering Education (SACHE) program is a cooperative effort between the Center for Chemical Process Safety members and engineering schools to provide education materials that bring elements of process safety into the education of students studying chemical engineering, mechanical engineering, and chemistry. Although these educational materials were originally developed for universities, they can also be used for engineers in industry. Effective education requires effective educational materials. The ultimate benefit of using effective educational materials is the elimination of accidents when handling hazardous materials, including chemicals and dusts. The targeted industries include chemical, pharmaceutical, biological, microchip, petroleum, etc. Additionally These Internet accessible materials include the most important safety concepts and safety technology; and are in a format that is effective for teaching, because they are developed by industrial experts who understand the principles of process safety, and professors who understand the principles of developing educational materials. Some examples of available products include (a) dust explosion control, (b) design for overpressure and underpressure protection, (c) movies on safety in chemical process industries, (d) emergency relief system design for single and two-phase flow, (e) chemical reactivity hazards, (f) mini case histories, and (g) inherently safer design. These materials are ready to use by educators in various computer formats, including PowerPoint presentations, Excel spreadsheets, and DVD movies. They can be downloaded and modified to fit the educator's style of teaching and to provide additional material to customize the content to better suit the audience. The SACHE products are available, internationally, to any SACHE member. A university membership allows all departments in the university to access and use the products. A company membership allows any company facility (internationally) to access and use the products. A very reasonable membership fee entitles members access to the specific year's products. Other years' products can be obtained for a membership fee for that year. The membership fee is a fraction of the value of the products. This article gives a complete list of available web-based SACHE products, with some descriptions. © 2007 American Institute of Chemical Engineers Process Saf Prog, 2007

Identification of kinetic models for the assessment of reaction hazards

AbstractThe assessment, control, and mitigation of reaction hazards is primarily based on the use of kinetic models. These kinetic models are used for the assessment of reaction hazards, the operation and control of the reactor, the design of emergency relief systems, estimation of the consequences of a reaction runaway, etc. The validity of these assessments depends highly on the validity of the kinetic model employed.Several steps are required to identify a suitable kinetic model. This includes: Selection of the model type. Estimation of the model's parameters using available data. Validation of the model. This article discusses each of these steps in detail and identifies problems associated with each step. Several practical examples are used to demonstrate these problems.The results show that (1) the results are sensitive to a number of assumptions, (2) mistakes may originate from misinterpretation of the thermal data, and (3) computational methods do exist to provide suitable kinetic models for hazard assessment.The analysis employed assumes a batch‐reaction system, since most of the kinetic data available is derived from batch calorimetric equipment. © 2007 American Institute of Chemical Engineers Process Saf Prog, 2007

Kinetics and hazards of thermal decomposition of methyl ethyl ketone peroxide by DSC

Differential scanning calorimetry (DSC) was applied to analyze thermal decomposition of methyl ethyl ketone peroxide (MEKPO). Thermokinetic parameters and thermal stability were evaluated. MEKPO decomposes in at least three exothermic decomposition reactions and begins to decompose at 30–32 °C. The total heat of decomposition is 1.26 ± 0.03 kJ g −1. Thermal decomposition of MEKPO can be described by a model of two independent reactions: the first is decomposition of a less stable isomer of MEKPO, followed by decomposition of the main isomer, after which an exothermic reaction of the reaction products with the solvent, dimethyl phthalate. The results can be applied for emergency relief system design and for emergency rescue strategies during an upset or accident.

Influence of calorimetric approximations on the design of emergency relief systems

The design of an emergency relief system (that is, a pressure safety valve or a rupture disk) for vessels, which may involve runaway reactions, requires knowledge of the chemical kinetics of the reactions involved. When safety-related problems are considered this is usually achieved using calorimetric tests, coupled with some suitable approximations on the kinetics of the reacting system. In this work we have analysed the extent to which the precise knowledge of the chemical kinetics influences the size of the relief system device for different reaction conditions. Decision criteria are proposed to identify situations where approximations in the kinetic mechanism lead to underestimation in the venting area.

Why DIERS technology should be used in risk assessment: Call for a 1999 worldwide benchmarking survey on various risk reduction methods used

AbstractThe Design Institute for Emergency Relief Systems (DIERS) Users Group has a membership of over 130 companies worldwide. It is an affiliate of the American Institute of Chemical Engineers. Its primary mission is to advance the technology and practice in the design of emergency relief systems for runaway reactions. This proposed survey is primarily on runaway reactions while recognizing there are many other venting applications of interes.The purpose of the survey is to benchmark various runaway risk reduction methods used from a risk and cost‐benefit basis. It will also promote the consistent use of the DIERS and other venting technologies in risk assessmen.Since it was first proposed by DIERS in March 1997, the survey has received much interest, not only from various international process safety, chemical engineering, and chemistry associations, but also from many non‐chemical associations worldwide. The survey is expected to be sent this year.This paper outlines the background, purpose and procedure of the proposed survey; why DIERS should be used and why it is apparently used inconsistently; the benefits of larger vents and higher vessel design pressures and the theme of the survey questions.Many of the broader issues of risk assessment were addressed in the 1994 DIERS Report, “Risk Consideration for Runaway Reactions,” Appendix 1 entitled “Addressing Some Issues Faced in Runaway Risk Assessment” [l].

Utilize plant data from emergency relief events to test design methods: A proposal to the AIChE DIERS users group

AbstractAdvanced methods for the design of emergency relief systems were developed under the auspices of the AIChE Design Institute for Emergency Relief Systems (DIERS). Rapid progress has continued, but most testing has been done at laboratory or small pilot plant scale. Full scale tests of design methods for emergency relief systems are much needed, but would be prohibitively expensive.Proposed here is a practical alternative: Use existing production data from operating plants to test design methods for emergency relief systems. Fortunately, although most emergency pressure relief events represent plant upsets and lost production, the relief system prevents a catastrophe in most process upsets. However, the qualitatively successful operation of an emergency relief system in a given upset does not represent proof of the design method employed. More importantly, it does not guarantee that the existing relief system will perform successfully in every credible upset that the process might experience in the future.Advocated here is an industry‐wide program to use data from selected process upsets to systematically evaluate the effectiveness of current emergency relief system design methods to quantitatively predict the performance of existing emergency relief systems. Products of this effort would include confirmation of a significant number of existing design methods, identification of deficiencies in current methods, and a published compendium of documented and evaluated case histories of full‐scale relief system performance. In addition to its instructive value to workers in emergency relief, the compendium could be used to test new design methods.This proposal is offered to the AIChE DIERS Users' Group. The DIERS Users' Group, which is comprised of over one hundred member companies, has representatives qualified to define, organize, sponsor, and execute a multi‐company research program of this type. (NOTE: At the semiannual meeting of the AIChE DIERS Users' Group in Calgary, Alberta, Canada on September 9, 1996, this proposal was presented to and adopted by the DIERS Users' Group and assigned to the Case Histories Committee.)

The DIERS users group: Status and current activities

AbstractOne hundred nine companies have formed the DIERS Users Group, a Design Institute of the AIChE, to cooperatively assimilate, implement, maintain and upgrade the DIERS methodology. The purpose of the group is to reduce the frequency, severity and consequences of pressure producing accidentsand develop new techniques which will improve the design of emergency relief systems. Membership in the DIERS Users Group offers access to refinements of the DIERS technology, participation in development of additional technology, and an opportunity to share learning experiences. Membership is open to industrial or engineering organizations interested in the design, use or manufacture of emergency relief devices and systems. Semiannual three‐day technical meetings are held at various locations and feature technology presentations by member company representatives and invited speakers and discussion of the results of computational example problems and experimental round robins. There are no fees for participation.

An advanced method for the estimation of reaction kinetics, scaleup, and pressure relief design

AbstractThis paper presents an advanced modeling approach which significantly improves predictions of reaction rates and critical data that engineers need to design effective pressure relief systems. Ideally, pressure relief systems are sized exactly for the reaction characteristics of the chemicals in the vessel. However, with many chemicals and chemical mixtures, reaction chemistry is difficult to characterize because the individual components interact in complex ways. Furthermore, the high cost and risk of full‐scale reactivity experiments make test data scarce. Chemical engineers bridge this gap in part with small‐scale tests and modeling computer codes such as the one developed by the Design Institute for Emergency Relief Systems (DIERS). The comprehensive approach developed in this paper provides a reliable design basis for difficult systems, including highly energetic and nonideal reactions, systems with continuing reactions in piping and containment vessels, and systems where homogeneous bubble collapse caused by rapid depressurization could cause a catastrophic vessel failure. We first examine possible mechanisms for catastrophic vessel failure and associated consequences. Next, we outline a detailed approach for emergency relief system design and reactivity testing.

Emergency pressure relief discharge control by passive quenching—update

AbstractA recent runaway reaction emergency relief system design includes a passive quench tank to collect and contain the two‐phase emergency relief discharge. This avoids the release of a large vapor cloud to the atmosphere and the attendant flammability and toxicity hazards. The feasibility of quenching is demonstrated with small scale experiments. A pressure relief simulation model is shown to accurately reproduce the observed temperature and pressure profiles in both the reactor and quench tank during relief. The model is then applied to the design of a full scale system. Quench system design considerations are discussed.

An overview of emergency relief system design practice

AbstractCost effective loss prevention requires an optimizing strategy to prevent, moderate (relieve) and contain runaway reactions. Ensuring that an emergency relief system design will either avoid or accommodate two‐phase vapor‐liquid flow is of particular importance. Use of adiabatic runaway reaction test information in combination with digital computer simulation is a powerful method to design an emergency relief system.

The DIERS users group: A forum for development/dissemination of emergency relief system design technology

AbstractDIERS was formed in 1976 to develop methods for the design of emergency relief systems capable of handling runaway reactions [1, 2]. Of particular interest at the time were when tow‐phase flow venting would occur and the applicability of different methods for sizing emergency relief systems for two‐phase, vapor‐liquid flashing flow. Approximately $1.6MM was devoted to investigations of two‐phase, vapor‐liquid onset/disengagement dynamics and the hydrodynamics of emergency relief systems.

Emergency relief system design for reactive and non‐reactive systems: Extension of the DIERS methodology

AbstractSimple mechanistic models for reactive and non‐reactive chemicals are summarized. The DIERS methodology has been extended as well as simplified to account for vapor disengagement and frictional effects including laminar flow conditions—both principal objectives of the DIERS program.