1、American Se O732290 ObL5088 420 I Petroleum Institute FUGITIVE EMISSIONS FROM REFINERY PROCESS DRAINS VOLUME II FUNDAMENTALS OF FUGITIVE EMISSIONS FROM REFINERY PROCESS DRAINS Discharge from Process Unit One or More Drain Pipes E- Drain Hub/Drain Funnel Opening HEALTH AND ENVIRONMENTAL SCIENCES DEPA
2、RTMENT PUBLICATION NUMBER 4678 APRIL 1999 Unsealed Drain Discharge from Process Unit One or More Drain Pipes Drain Hub/Drain Funnel Opening Reducer Grade Sealed (Trapped) Drain STDaAPIIPETRO PUBL 4678-ENGL 19 m 0732290 0635089 367 R -%- American Petroleum Institute American Petroleum Institute Envir
3、onmental, Health, and Safety Mission and Guiding Principles MISSION The members of the American Petroleum Institute are dedicated to continuous efforts to improve the compatibility of our operations with the environment while economically developing energy resources and supplying high quality produc
4、ts and services to consumers. We recognize our responsibility to work with the public, the government, and others to develop and to use natural resources in an environmentally sound manner while protecting the health and safety of our employees and the public. To meet these responsibilities, API mem
5、bers pledge to manage our businesses according to the following principles using sound science to prioritize risks and to implement cost-effective management practices: PRINCIPLES a O To recognize and to respond to community concerns about our raw materials, products and operations. To operate our p
6、lants and facilities, and to handle our raw materials and products in a manner that protects the environment, and the safety and health of our employees and the public. To make safety, health and environmental considerations a priority in our planning, and our development of new products and process
7、es. To advise promptly, appropriate officials, employees, customers and the public of information on significant industry-related safety, health and environmental hazards, and to recommend protective measures. To counsel customers, transporters and others in the safe use, transportation and disposal
8、 of our raw materials, products and waste materials. To economically develop and produce natural resources and to conserve those resources by using energy efficiently. To extend knowledge by conducting or supporting research on the safety, health and environmental effects of our raw materials, produ
9、cts, processes and waste materials. To commit to reduce overall emission and waste generation. To work with others to resolve problems created by handling and disposal of hazardous substances from our operations. To participate with government and others in creating responsible laws, regulations and
10、 standards to safeguard the community, workplace and environment. To promote these principles and practices by sharing experiences and offering assistance to others who produce, handle, use, transport or dispose of similar raw materials, petroleum products and wastes. STD.API/PETRO PUBL 4b7-ENGL 399
11、9 I 0732290 Ob35090 O9 m Fugitive Emissions From Refinery Process Drains Volume II Fundamentals of Fugitive Emissions From Refinery Process Drains Health and Environmental Sciences Department API PUBLICATION NUMBER 4678 PREPARED UNDER CONTRACT BY: 100 WEST HARRISON STREET SEATTLE, WASHINGTON 981 19-
12、41 86 BROWN AND CALDWELL RICHARD L. CORSI THE UNIVERSITY OF TEXAS AT AUSTIN AUSTIN, TEXAS APRIL 1999 American Petroleum Institute STD.API/PETRO PUBL 46743-ENGL 1999 E 0732270 Ob15091 T15 6 FOREWORD API PUBLICATIONS NECESSARILY ADDRESS PROBLEMS OF A GENERAL NATURE. WITH RESPECT TO PARTICULAR CIRCUMST
13、ANCES, LOCAL, STATE, AND FEDERAL LAWS AND REGULATIONS SHOULD BE REVIEWED. API IS NOT UNDERTAKING TO MEET THE DUTIES OF EMPLOYERS, MANUFAC- TURERS, OR SUPPLIERS TO WARN AND PROPERLY TRAIN AND EQUIP THEIR EMPLOYEES, AND OTHERS EXPOSED, CONCERNING HEALTH AND SAFETY RISKS AND PRECAUTIONS, NOR UNDERTAKIN
14、G THEIR OBLIGATIONS UNDER LOCAL, STATE, OR FEDERAL LAWS. NOTHING CONTAINED IN ANY API PUBLICATION IS TO BE CONSTRUED AS GRANTING ANY RIGHT, BY IMPLICATION OR OTHERWISE, FOR THE MANU- FACTURE, SALE, OR USE OF ANY METHOD, APPARATUS, OR PRODUCT COV- ERED BY LETTERS PATENT. NEITHER SHOULD ANYTHING CONTA
15、INED IN ITY FOR INFRINGEMENT OF LETTERS PAmNT. THE PUBLICATION BE CONSTRUED AS INSURING ANYONE AGAINST LIABIL- All rights reserved. No part of this work muy be reproduced, stored in a retrieval system, or transmitted by any means, electronic, mechanical, photocopying, recording, or otherwise, withou
16、t prior written permission from the publisher: Contact the pulishec API Publishing Services, 1220 L Street, N. U!, Washington, D.C. 20005. Copyright O 1999 American Petroleum Institute iii ACKNOWLEDGMENTS THE FOLLOWING PEOPLE ARE RECOGNIZED FOR THEIR CONTRIBUTIONS OF TIME AND EXPERTISE DURING THIS S
17、TUDY AND IN THE PREPARATION OF THIS REPORT: API STAFF CONTACT Paul Martino, Health and Environmental Sciences Department MEMBERS OF THE REFINERY DRAINS EMISSIONS PROJECT GROUP Nick Spiridakis, Chairman, Chevron Research and Technology Kare1 Jelinek, BP Oil Company Miriam Lev-On, Arco Gary Morris, Mo
18、bil Technology Company Chris Rabideau, Texaco Manuel Cano, Shell Development Company Achar Ramachandra, Amoco Corporation Jeff Siegell, Exxon Research and Engineering Ron Wilkniss, Western States Petroleum Association Jenny Yang, Marathon Oil Company Brown and Caldwell would also like to thank Dr. R
19、ichard Corsi (University of Texas) for his assistance in the completion of this work. iv STD*API/PETRO PUBL 4b78-ENGL 1999 W 0732290 Ob35093 898 D PREFACE The results of this study are presented in three separate reports. Volume I entitled “fugitive Emission Factors for Refinew Process Drains“ (API
20、Publication Number 4677) contains simplified emission factors that can be used to quickly estimate total volatile organic compound (VOC) emissions from refinery process drains. Volume II entitled “Fundamentals of Fugitive Emissions from Refinery Process Drains“ (API Publication Number 4678) describe
21、s theoretical concepts and equations that may be used in a model (APIDRAIN) to estimate speciated VOC emissions. The model can provide insight on how to change process drain variables (flow rate, temperature, etc.) to reduce emissions. Volume III entitled “APIDRAIN Version 7.0, Process Drain Emissio
22、n Calculator“ (API Publication Number 4681) is the computer model with users guide to estimate emissions from refinery process drains. The software allows users to calculate VOC emissions based on the emission factors in Volume I and equations for speciated emissions in Volume II. All three volumes
23、of this study can be purchased separately; however, it is suggested that the user consider purchase of the entire set to gain a complete understanding of fugitive emissions from refinery process drains. STD.API/PETRO PUBL 4b78-ENGL 1999 0732290 Ob15094 724 TABLE OF CONTENTS Pane EXECUTIVE SUMMARY ST
24、ATEMENT OF NEED . ES-I IMPROVED MODEL ES-I CONCLUSIONS . e5-2 i . INTRODUCTION STATEMENT OF NEED 1-1 OBJECTIVES 1-1 SCOPE . 1-2 ORGANIZATION OF REPORT . 1-3 2 . WO-ZONE EMISSIONS MODEL MODEL OVERVIEW . 2-1 Mass Transfer Fundamentals . 2-1 Overview of Two-Zone Model . 2-3 ZONE I SUBMODEL 2-4 ZONE 2 S
25、UBMODEL 2-6 THE INTEGRATED MODEL . 2-8 3 . EXPERIMENTAL METHODOLOGY EXPERIMENTAL SYSTEMS 3-1 Laboratory Drain System (LDS) 3-1 Trap Simulators 3-4 CHEMICAL TRACERS / TRACER PREPARATION 3-7 ANALYTICAL METHODS . 3-9 Liquid Samples . 3-9 Gas Samples 3-10 DATA ANALYSIS: OVERVIEW 3-11 Stripping Efficienc
26、ies 3-11 Mass Transfer Coefficients . 3-11 ZONE 2 ANALYSIS . 3-12 Experimental System (zone 2) . 3-12 Experimental Plan and Methodology (zone 2) . 3-14 Data Analysis (zone 2) 3-1 9 Experimental System (zone 1) . 3-24 Experimental Plan and Methodology (zone 1) . 3-25 QUALITY ASSURANCE 3-30 ZONE 1 ANA
27、LYSIS . 3-24 Data Analysis (zone I) 3-28 4 . EXPERIMENTAL RESULTS ZONE 1 . 4-1 Experimental Results: Stripping Efficiencies 4.1 Correlations: Mass Transfer Parameters for Zone 1 4.5 ZONE 2 . 4-12 Experimental Results: Stripping Efficiencies 4.12 Correlations: Mass Transfer Parameters . 4-15 STD.API/
28、PETRO PUBL 4678-ENGL 1999 I 0732290 Ob15095 bbO TABLE OF CONTENTS 5 . MODEL INTEGRATION AND APPLICATIONS SUMMARY OF EMISSIONS MODEL 5-1 Comparison With Existing Models 5-4 6 . SUMMARY AND CONCLUSIONS SUMMARY 6-1 CONCLUSIONS 6-1 7 . REFERENCES . 7-1 LIST OF TABLES Pase Table 3.1 . Table 3.2 . Table 3
29、.3 . Table 3-4 . Table 3.5 . Table 3.6 . Table 3.7 . Table 3.8 . Table 3.9 . Table 3.10 . Table 3-1 1 . Table 3.12 . Table 3.13 . Table 3.14 . Table 4.1 . Table 4.2 . Table 4.3 . Table 4-4 . Table 4.5 . Table 4.6 . Table 4.7 . Table 4.8 . Volatile Tracers . 3-7 Summary of Tracer Bag Preparation 3-8
30、Summary of Zone 2 Experiments 3-14 Initial Liquid-Phase Tracer Concentrations in the Reservoir 3-15 Liquid Sampling Schedule 3-16 Gas Sampling Schedule For Zone 2 Experiments -3-1 8 Summary of Air Entrainment Experiments 3-25 Summary of Bubble Mass Transfer Experiments 3-26 Summary of Surface Volati
31、lization Experiments 3-27 Concentrations of Scott Specialty Gases Standards Cylinder . 3-31 Liquid- and Gas-Phase Method Detection Limits (MDLs) . 3-33 Analytical Liquid Standards Prepared from TedlarTM Bag #7 3-31 Analytical Gas Standards Prepared from Scott Specialty Gases Cylinder . 3-32 Mass Clo
32、sure Analysis . 3-36 Stripping Efficiencies Due to Entrained Air Bubbles (q,) . 4-3 Zone 1 Stripping Efficiencies (q,) 4-3 Stripping Efficiencies Due to Surface Volatilization in a Trap (qS) 4-4 Measured Degrees of Equilibrium (y) for Entrained Bubbles . 4-10 Calculated Values of KLAS 4-11 Measured
33、Stripping Efficiencies for Channel (q2) 4-14 Calculated Values of KLA, . 4-15 Measured Higbie, 1935; Danckwerts, i 951 ; Dobbins, 1956): where: flux across interface from liquid to gas (M/L2T) overall mass transfer coefficient (LA-) liquid-phase concentration of compound (M/L3) gas-phase concentrati
34、on of compound (M/L3) Henrys law constant ( L3,4LBgas) - ra - KL Cl c, Hc - - - The term in brackets is often referred to as a concentration driving force, and represents how far a system is from a state of chemical equilibrium. The overall mass transfer coefficient, KL, can be further reduced to it
35、s gas- and liquid-phase components. This concept, stemming from two-film theory, models mass transfer as a steady-state molecular diffusion process occurring 2- 1 across two quiescent boundary films, one in the liquid phase and one in the gas phase (Lewis and Whitman, 1924): where: liquid-phase mass
36、 transfer coefficient (LIT) gas-phase mass transfer coefficient (Ln) Henrys law constant (L31iq/L3w) - kl 44 Hc - - The inverse of the overall mass transfer coefficient is often referred to as an overall resistance to mass transfer. This analogy to electrical resistance illustrates the liquid-phase
37、(Ilkl) and gas- phase resistance (I/bHc) to mass transfer. Based on two-film (Lewis and Whitman, 1924), penetration (Higbie, 1935), and surface- renewal (Danckwerts, 1951) theories, the following relationships were developed. These relationships allow comparison of liquid- and gas-phase mass transfe
38、r coefficients for two different compounds: where Yi, yg = kli - kij - kgi= kgi - DI - mass transfer proportionality constants between compounds (-) liquid-phase mass transfer coefficient for compound i (Lm) liquid-phase mass transfer coefficient for compound j (LlT) gas-phase mass transfer coeffici
39、ent for compound i (L/T) gas-phase mass transfer coefficient for compound j (UT) liquid-phase molecular diffusion coefficient for compound i (L2/l) 2-2 STD-APIIPETRO PUBL 467B-ENGL 1997 I 0732290 Ob15105 33T Du - Dgi = gas-phase molecular diffusion coefficient for compound i (L2T) D, = gas-phase mol
40、ecular diffusion coefficient for compound j (L2/T) n, m = power constants (-) liquid-phase molecular diffusion coefficient for compound j (L2/T) The power constants n and m can vary from anywhere between unity (for two-film theory) and 0.5 (for penetration and surface-renewal theories). When a compo
41、und possesses an extremely large Henrys law constant, it may be possible to neglect the gas-phase resistance to transfer and thereby simplify Equation 2-2 to KL w k,. This is often done for oxygen, a commonly studied compound with an H, value of 32 m3,iq/m3gas at 25 OC. Conversely, for very low vola
42、tility chemicals such as acetone, it is often possible to neglect the liquid-phase resistance altogether, and to express Equation 2-2 as KL = k,-,H,. Once reference chemicals such as oxygen and acetone have been used to estimate liquid- and gas-phase mass transfer coefficients, Equations 2-3 and 2-4
43、 can be used to calculate mass transfer coefficients for any compound. Overview of Two-Zone Model Within a specific process drain, there are several locations where mass transfer can occur. In each case, different emission mechanisms are responsible. Figure 2-1 shows two typical process drains, one
44、open and one trapped. Each drain is subdivided into one or two zones from which emissions may occur. Zone I extends from the bottom of the discharge nozzle to the water seal (inclusive of the water seal); mass transfer in this region is attributed to surface volatilization and air entrainment. The o
45、riginal intent of this study was to separate surface volatilization associated with the falling film from that associated with the underlying water seal. This proved to be experimentally difficult and, as such, the two surface volatilization components were “lumped” for zone 1. Based on the degree o
46、f splashing and the longer residence time within the waterseal, .e., relative to the falling film, it can be reasonably assumed that volatilization at the water seal is significantly greater than from the falling film. Zone 2, present in both trapped and untrapped drains, fotlows the falling film as
47、 it impacts the underlying channel. In this zone, splashing in the channel is likely the primary emission mechanism. 2-3 STD.API/PETRO PUBL 4b7-ENGL 1999 111 0732290 ObL51ib 27b W Figure 2-1. Different Emission Zones in an Industrial Process Drain ZONE I SUBMODEL According to the American Petroleum
48、Institute (API), over 80% of all petroleum refinery process drains are equipped with a water seal, provided by a P-trap, J-trap or similar device (American Petroleum Institute, 1996). As stated earlier, these water seals are designed to minimize the amount of fresh air entering the sewer, thus lower
49、ing the concentration driving force in the channel headspace and reducing VOC emissions. Even so, emissions still occur in a trapped drain. Zone 1 encompasses the falling film as well as the water seal (trap). Within zone I , it is assumed there are two major mechanisms by which chemicals can volatilize. The first involves surface volatilization which occurs from the falling film and the upstream surface of the water seal. Splashing is the most visible manifestation of this mechanism. The second major mechanism is air entrainment induced by the boundary layer of air that surrou
