Emergency Relief System Design Using DIERS Technology: The Design Institute for Emergency Relief Systems (DIERS) Project Manual by H. G. Fisher, H. S. Forrest, S. S. Grossel, J. E. Huflf, A. R. Müller, J. A. Noronha, D. A. Shaw and B. J. Tilley Copyright 1992 American Institute of Chemical Engineers Index A All-liquid effluent, 32 All-vapor effluent, 32 Approximate equilibrium-rate (ERM) flow model, 73-74,399-400 Approxi mate homogeneous-nonequi librium model, 73-74 Area : charge method for emergency relief system design, 440-443 top vent testhop ERS devioe, 376-377, 440-441 bottom vent test/top or bottom ERS dwice, 377-378.44243 Area reduction with presswe recovery, hypothetical, 126125 B Baroay correlation and pipe flow, 83,M Best estimate procedure to calculate hvo-phase vapor-liquid flow onwdisengagement, 25-29 Blowdown drum cydone with integral catchtank, 315-316. 325 cydone with separate catchtank, 315, 322325 disposal of vapors from, 329-332 horizontal, 314-315,3%321 multireactor, 318,328-329 +n-top. 316,326 quencher, 317,326328 sizing of, 319-329 Blowdown load considerations, 363 Bottom-vented vessels, estimating void fraction for, 34 Bubble rise velocity, 7-10,27 Bubbly onsevdisengagement vessel model, 7-10,27,28 coupling equation and, 17-19 C Catchtanks mechanical design, 333 safety considerations, 333 Choked/aitical flow, 52.60-61 Chum-turbulent onsevdisengagement vessel model. 8-10,27-29 coupling equation and. 17-19 Complete vapor-liquid disengagement model, 16 Complex fluids, 56-57 Containment, pressure relief system design and, 313-329 Coupling equation, 5-8,17-19 Cydone knock-out. 315-316,322-326 integral catchtank, 315-316,325 separate catchtank, 315,322-325 D DEERS computer program for emergency relief system design, 34-41 533
534 Index DIERS (Design Institute for Emergency Relief Systems) experimental program observations, 13-3- 169 DIERS bench-scale apparatus, 365-448 limitation of previous test equipment, 366 requirements, -365-366 DIERS high viscosity relief flow tests, 289-3 12 large-scale pol ystyrene-ethylbenzene bottom-vented tests. 296-297 large-scale rubber cement tests, 293-295 project overview, 291 small-sale rubber cement bottom-vented tests, 293 DIERS large-sale integral tests analysis of, 133-138 comparison with other models, 145-146 discussion of results, 143-145 program description, 138-141 program objectives, 138 test configurations, 141.171-188 test results, 141-169.189-237 DIERS model choice for pipe friction factor, 81-89 Dimensionless superficial vapor velocity. 27-29 Discharge of vapors from separatorkatchtank, 329-332 to atmosphere, 329-330 to flare stack or incinerator. 330-332 through scrubber, 330 through vent condenser, 3-30 Disposal, pressure relief system design and, 329-332 Duct entrancedshort tubes, 78-79 Duct expansion, 80 Dynamic load factor, 349 E Effluent with partial disengagement, 33-34 Emergency pressure relief of vessels, energy and material balance derivations, 42-47 Emergency relief system (ERS) design analytical methodsfn nomograph, 376, 418-425 area : charge scaling, 376-378,440443 DEERS computer program, 34-41 experimental sizing, 382-448 experimental safety considerations, 382 Fauske analytical methods, 418-425 flashing (choked) flow-approximate ERM model, 73-74,399400 flashing (choked) flow-generalized HEQ correlation, 4004Q4 flashing (unchokedynonflashing (unchoked) flow, 405-411 hung analytical methods, 426441 mixed flashing and nonflashing flow, 411 nonflashing (unchoked) flowincompressible Bernoulli equation, 410411 Emergency relief system sizing remnmendations, 382-448 for fire exposure, 44-3-445 safety considerations, 382 calculation considerations, 382-385 thermal stability testing and data adjustment, 385-393 onsevdisengagement behavior testing, 37-3-375,393-3% flow rate calculationlvisaxity characterization, 375,396417 Fauske analytical methodsfai nomograph, 418-425 Energy balance, 42-47 evaluation of internal energy function, 44 ideal gasfincompressible liquid case, 44-45 simplification for small feed and effluent flows, 43 simplification for uniform vessel conditions, 4-W4 Equilibrium flash calculations, 105-106 Equilibrium flow, 53 Equilibrium-rate (ERM) flow model, 68-73, 117-119 approximate, 73-74, 399-400 example problems, 117-119 Experimental safety considerations in ERS design, 382
F Fauske analytical methods, 418-425 Fire exposure and emergency relief system design, 443445 Flashing (choked) flow-approximate ERM model, 73-74,399-400 Flashing (choked) flow-generalized HEQ correlation, 400404 Flashing (unchoked) flow, 405-411 Flashing (unchoked)/nonflashing (unchoked) flow, 405-411 Flow computations, thermophysical property requirements, 104 Flow path length, 74 Flow ntehriscosity characterization testing, 3753-17 flashing (choked) flow-approximate ERM equation, 73-74,399-400 flashing (choked) flow-generalized HEQ correlation, 4OO-404 flashing (unchoked) flow, 405411 flashing (unchoked)/nonflashing (unchoked) flow, 405-411 mixed flashing and nonflashing flow, 411 nonflashing (unchoked) flowincompressible Bernoulli equation, 410-411 Fluid behavior in venting vessels, 30-41 all-liquid effluent, 32 all-vapor effluent, 32 effluent with partial disengagement, 33-34 homogeneous (ngslip) effluent, 32-33 void fraction, 30-31 Foamy two-fluid model, JAYCOR, 20 G Gassy/nontempered readion, 376 General flow equation(s) energy balance, 60 momentum balance, 60 slip flow, 58-59 two-phase speci fic vd umes, 58-59 H Henr y-fauske homogeneous-nonequilbrium (HNE) flow model. 6668,114-117 High viscosity flashing two-phase flow, 57, 289-312 general discussion, 289-290 necessity for mnservatism, 290-291 recommended design practices, 297-305 special considerations, 290 uncertainties, 305-306 Holdup model for pipe fridion factor, 82-86 Homogeneous-equilibnum (HEM) flow model, 71-73 example problems, 120-123 Homogeneous flow, 53,84436 Homogeneous-frmn flow model, 69, 119 Homogeneous-nonequilibrium model, 64-68 example problems, 114-117, 123-124 Homogeneous (no-slip) effluent, 32-33 Homogeneous onsevdisengagement vessel model; 6,32-33 Hybridhontempered reaction, 375-376 Hybridhempered reaction, 375 I Internal energy alternate formulation of, 45 and venting calculations, 48-49 J JAYCOR DEERS computer program, 3641 foamy two-fluid model. 20-21 nonfoamy two-fluid model, 20-23 two-fluid model, 19-23.34-41 K hodt4ut drums, 314318,322-329, see ako specific types L Laminar pipe flow, 297-312 hung analytical methods for emergency relief system design, 426440
Method I-vdatile/tempered reaction, 428-430.432438 Method II-hybridhempered reaction, 430-431 Method IIl-hybrid/nontempered or gassyhontempered reactions, 431432,438-440 Liquid swell, 25 variables affecting, 527 Lodrhardt-Martinelli slip correlation, 85-86 Long-pipe models, sample problems, 126-130 Low-pressure reclosing devices, 93 M Material and energy balance derivations, 42-46 Maximum (critical) flow, 60-61 Mechanical design of pressure relief systems, 332-363 catchtank mechanical design, 333 catchtank safety considerations, 333 vent piping considerations, 332-333 Mixed flashing and nonflashing flow, 411 Modified Schrock model, 69-70 example problem, 119-120 Momentum balance. 60 Multireactor knock-out drum with catchtank, 318,32&329 N Newtonian flow, 53-56.299-33 rupture disk system, 53-54 safety relief valve system, 55-56 Nonboiling height onset/disengagement vessel model, 10-16 coupling equation and, 17-19 Nonequilibrium flow, 63-70 Non flashi ng (unchoked) flow-incompressible Bernoulli equations, 410411 Nonfoamy two-fluid model, JAYCOR, 20-2.3 Non-Newtonian fluids, 56-57 pipe flow for, 303-305,310-311 Nmle(s) discharge coefficients, 75-77.107-110 flow models, 61-77,114-123 Numerical integration, 89 0 OnseVdisengagement behavior testing, 373-375,393-3% OnseVdisengagement vessel model, 10-16, 27-29 Orifice plates, 77-78, 108-110 P Pipe entrance sections. model parameters, 107-110 Pipe friction factor, 81-89 Baroczy correlation and pipe flow, 87-84 DIERS model choice. 86-88 general flow equation, 81 holdup model, 82-87 homogeneous model, 8446 Lockhard 1-Mar ti nel I i correlation, 85-86 Reynolds number and, 81-82 Pipe flow for non-newtonian (power-law) fluids, 297-300,303-305 Pressure relief system flow, 51-130 complex fluids, %97 miscellaneous devices, 95 networks, 95 recommended design methods, 53-58 rupture disk systems, 95 sample problems 11S-130 typical installation, 90 valve capacity, 90-91 valve stability, 91-93 Q Quality, 30-31,52 Quencher knodr-out drum with catchtank, 317.326-328 R Reaction force equations, 334-337
Reaction forces, general, 334 Reaction forces from rupture disk discharge, 34S361 dynamic load fador, 361 venting of gases, 349-351 venting of liquids, 352 venting of two-phase mixtures, 352-361 Reaction forces on safety valve naaledpiping, 337-349 dynamic load factor, 349 venting of gases, 337-341 venting of liquids, 341 venting of two-phase mixtures, 341-348 Relief system flow calculations, background technology, 58-97 Reynolds number area ratio effects and, 77 pipe friction factor and, 81-86 Rupture disk application to pressure relief systems, 94 pipe flow, 53-54,95 readion forces from discharge, 34S361 transient effects of reaction forces, 361-362 S Safety relief valve see ako Pressure relief system flow associated piping, 92 naule flow, 57-58,61-77,114-123 outlet size restrictions, 92-94 reaction foms on, 337-349 stability, 91-93 SAFIRE computer program for emergency relief sizing, 449-530 architecture, 45-1-455 chemical reactions, 4-1 computer routines in, 111-112 external heat fluxes, 464465 flash calculations, 4 5 m mass and energy balances, 465467 overview, 450-452 vent flow calmlations, 461-462 vessel hydrodynamics, 4 6 M Sample problems for pressure relief system flow, 113-130 Sharp reductions, 77-79 Short-pipe models, sample problems, 123-126 Slip flow, 58-59,82-86 Stagnation conditions, 52 Subcooled liquid flow, 57, 74-75 Superfiaal vapor veld ty, 27-29 T Thermal stability testing, data adjustment, 385-393 Thermophysical property requirements for flow computation, 104 Thrust restraint design, 362 Top-biased vap generation, 10-16 Top-vented vessels, estimating void fraction for, 31-34 Transient effects of reaction forces, rupture disks, 361-362 -0-phase blowdown example, 25-26 Two-phase liquids, general flow equations, 51-132?ko-phase specific volume, 5%59-0-phase vapor-liquid flow onsev disengagement best estimate procedure to calculate, 25-29 experimental procedure to differentiate, 26,393-3% DIERS calculation methodology for, 27-29 U Uniform vapor generation, 11 V Vapor disengagement dynamics, 1,2541 design considerations, 2 Vapor holdup, 52 Vapor-liquid equilibrium, 105-106 Vapor-liquid slip, -30 Vapors from separatorlcatchtank, discharge of, 329-332
538 Index Vent flow models, 16 Vena contracts area, 77-78,107-109 Vent piping mnsiderations, 332-333 Venting of gases, 337-341,349-351 and internal energy calculations, -9 of liquids, 341,352 of two-phase mixtures, 341-348,352-361 Vessel flow models, 6-16 Void fraction, 30-31 alternatives for calculating. 34-41 estimating for bottom-vented vessels, 34 estimating for topvented vessels, 31 Watilehempered reaction, 375