1、Ame ri c an Petroleum Ins ti tut e FUGITIVE EMISSIONS FROM EQUIPMENT LEAKS I: MONITORING MANUAL Health and Environmental Affairs Department Publication Number 342 May 1998 STDmAPIIPETRO PUBL 342-ENGL 1998 0732290 060b50b 999 American Petroleum Institute American Petroleum Institute Environmental, He
2、alth, 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 products and servi
3、ces 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 members pledge
4、to manage our businesses according to the following principles using sound science to prioritize risks and to implement cost-effective management practices: PRINCIPLES o o To recognize and to respond to community concerns about our raw materials, products and operations. To operate our plants and fa
5、cilities, 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 processes. To advis
6、e 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 of our raw
7、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, products, process
8、es and waste materials. .To commit to reduce overall emission and waste generation To work with oihers 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 standards t
9、o 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. Fugitive Emissions From Equipment Leaks I:
10、Monitoring Manual Health and Environmental Affairs Department API PUBLICATION NUMBER 342 PREPARED UNDER CONTRACT BY: RON RICKS RADIAN INTERNATIONAL LLC 10389 OLD PLACERVILLE ROAD SACRAMENTO, CA 95827 MAY 1998 American Petroleum I Institute FOREWORD API PUBLICATIONS NECESSARILY ADDRESS PROBLEMS OF A
11、GENERAL NATURE. WITH RESPECT TO PARTICULAR CIRCUMSTANCES, 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 HEAL
12、TH AND SAFETY RISKS AND PRECAUTIONS, NOR UNDERTAKING 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- ER
13、ED BY LETTERS PATENT. NEITHER SHOULD ANYTHING CONTAINED IN ITY FOR INFRINGEMENT OF LETTERS PAmNT. THE PUBLICATION BE CONSTRUED AS INSURING ANYONE AGAINST LIABIL- All rights reserved. No part of this work may be reproduced, stored in a retrieval system, or transmitted by any means, electronic, mechan
14、ical. photocopying, recording, or otherwise, without prior written pennisswn from the publishel: Contact the publisher; API Publishing Services, I220 L Street, N.W, Washington, D.C. 20005. Copyright O 1998 American Petroleum institute iii Previous page is blank STD.API/PETRO PUBL 342-ENGL 1998 07322
15、90 ObOb509 bT ACKNOWLEDGMENTS THE FOLLOWING PEOPLE ARE RECOGNIZED FOR THEIR CONTRIBUTIONS OF TIME AND EXPERTISE DURING THIS STUDY AND IN THE PREPARATION OF THIS REPORT: API STAFF CO “TACT Karin Ritter, Health and Environmental Affairs Department MEMBERS OF “E FUGITIVE MEA SUREMENT GROUP Miriam Lev-
16、Section 3.0 identifies monitoring equip- ment that meet U.S. EPA Method 21 specifications; Section 4.0 discusses quality control; Section 5.0 explains the screening proce- dure; Section 6.0 adresses alternative measur- ement methods; and Section 7.0 includes the references. SECTION 2.0 EQUIPMENT INV
17、ENTORIES An accurate equipment inventory is essential for most inspection and maintenance (UM) programs, as defined in this volume, and for determining the amount of emissions from equipment leaks, as provided in Volume II. This section identifies the process equipment that may be subject to equipme
18、nt leak regulations and explains how to count and keep track of these components. 2.1 EQUIPMENT TYPES The primary equipment types (or component types) that could be sources of fugitive emissions Agitators; Compressors ; Connectors; Open-ended lines; Pressure relief devices; pumps ; Sampling connecti
19、ons; Valves; and Others. Graphical depictions of these types of components are shown in Section 5.0 of this volume. The seals on agitators, compressors and pumps are the source of equipment leaks associated with these equipment types; thus, the emissions from these equipment types are often describe
20、d as from agitator seals, compressor seals and pump seals. In this volume and the companion volume (Volume II), this terminology (with or without seals) is often used interchangeably. For example, a leak could be described as coming from a “pump“ or from a “pump seal.“ Due to the evolving nature of
21、nomenclature, other terminology is also often used interchangeably to describe equipment types. For example, connectors can also be referred to as “fittings.“ Subsequent sections of this report provide a description of these component types and information related to how these components leak. 2.1.1
22、 Agitators Agitators are used to stir or blend chemicals. Four seai arrangements are commoniy used with agitators: packed seals, mechanical seals, hydraulic seals, and lip seals. A packed seal consists of a cavity, called a stufting box, in the agitator casing filled with a packing gland to form a s
23、eal around the shaft. There are several types of single mechanical seals, with many variations to their basic design and arrangement, but all have a lapped seal face between a stationary element and a rotating seal ring. There are also many variations of dual and tandem mechanical seals. Dual mechan
24、ical seals with the following characteristics are 2-1 considered to be leak free (and therefore 2.1.3 Connectors typically do not require monitoring): Connectors are used to join sections of Barrier fluids pressurized higher than piping and equipment. Connectors can be flanges, screwed or threaded c
25、onnectors, union connectors, tubing connectors, caps, plugs, etc. Flanges are bolted, gasket-sealed connectors. the agitator cavity; A barrier fluid reservoir vented to a control device; and A pressure tight barrier fluid with a pressure alarm indicator. Flanges are normaily used for pipes with diam
26、eters of 2.0 inches or greater. The primary causes of flange leakage are poor installation, aging and deterioration of the gasket, thermal stress and vibration. Flanges can also leak if improper gasket material is chosen. In a hydraulic seal, an annular cup attached to the process vessel contains a
27、liquid that contacts an inverted cup attached to the rotating agitator shaft. Although it is the simplest agitator shaft seal, the hydraulic seal is limited to low ternperatureAow pressure applications and can handle only very small pressure changes. A lip seal consists of a spring-loaded, non- lubr
28、icated elastomer element, and is limited in application to low-pressure, top-entering agitators. The non-flange connectors (screwed, union, tubing, caps, plugs, etc.) typically are used to connect piping and equipment having diameters of 2.0 inches or less. Emissions from these connectors can occur
29、as the sealant ages and eventually cracks. Leakage can also occur as the result of poor assembly or sealant application, or from thermal stress or vibration on the piping and fittings. Agitator seals can leak because of poor installation, aging, and deterioration of the seals themselves, thermal str
30、ess, and vibration. 2.1.4 ODe n-ended Lines 2.1.2 CornDressors Some valves are instailed in a system so that Compressors provide the force to transport gases through a process unit in much the same way that pumps transport liquids. There are centrifugal, reciprocating, and rotary compressors in use
31、by industries affected by equipment leak regulations. The sealing mechanisms for compressors are similar to the packed and mechanical seals for agitators. they function with the downstream line open to the atmosphere. A faulty valve seat or incompletely closed valve on such an open-ended line would
32、result in a leakage through the open end. in some locations open-ended lines are prohibited. A cap, plug, or blind flange used to control leaks from open-ended lines can also leak from improper installation and aging and deterioration of the gasket or threads. Because these leaks are similar to thos
33、e found in connectors, a potentially open-ended line that is 2-2 STD.API/PETRO PUBL 342-ENGL capped, plugged, or blind flanged is counted as a connector. 2.1.5 Pressure Relief Devices Pressure relief devices are safety devices commonly used in petroleum and chemical facilities to prevent operating p
34、ressures from exceeding the maximum allowable working pressures of the process equipment. Note that when a pressure relief device functions as designed during an over-pressure incident and allows pressure to be reduced it is not considered an equipment leak. Equipment leaks from pressure relief devi
35、ces occur when material escapes from the pressure relief device when it is in the closed position. These leaks can occur from the aging and deterioration of packing or sealing materials. The most common pressure relief device is a spring-loaded pressure relief valve (PRV). The PRV is designed to ope
36、n when the operating pressure exceeds a set pressure and to reseat after the operating pressure has decreased to below the set pressure. Another pressure relief device is a rupture disk. Rupture disks are sometimes used upstream of PRVs to control emissions during nod operations. These disks rupture
37、 when a set pressure is exceeded, thereby allowing the system to depressurize. Rupture disks do not permit emissions during nonnal operations. During no however, other types, such as the positive displacement (reciprocating) pump, are also used. Liquids transferred by pump can leak at the point of c
38、ontact between the moving shaft and the stationary casing. Consequently, all pumps except the sealless types, such as canned-motor, magnetic drive, and diaphragm pumps, require a seal at the point where the shaft penetrates the housing in order to isolate the pumped fluid from the environment. Seall
39、ess pumps do not have fugitive emissions. Packed and mechanical seals for pumps are similar in design and application to packed and mechanical seals for agitators. Packed seals can be used on both reciprocating and centrifugal pumps. Mechanical seals are limited in application to pumps with rotating
40、 shafts. “he cause of pump seal leaks are similar to those described for agitators. 2.1.7 Samolinn Connections Sampling connections are fittings where samples are routinely taken for process and quality control purposes. A sampling connection has a specific function (to aid in sample taking) with sp
41、ecific types of emissions that are distinct from those described previously. A sampling connection can leak from a faulty valve seat or incompletely closed valve that is upstream of the sampling connection. A sampling connection 2-3 STD=API/PETRO PUBL 342-ENGL I1998 0732270 ObOb520 269 M can also ha
42、ve emissions from the flushing of the line during the sampling process. 2.1.8 Valves Except for connectors, valves are the most common process equipment type found in the petroleum industries. Valves are available in many designs, and most contain a valve stem that operates to restrict or allow flui
43、d flow. Typically, the stem is sealed by a packing gland or O-ring to prevent leakage of process fluid to the atmosphere. Emissions from vaives occur at the stem or gland area of the valve body when the packing or O-ring in the valve deteriorates. Some emissions could also occur from the valve housi
44、ng, generally at the bonnet flange. Bellows valves and rubber diaphragm valves have negligible emissions as long as there is not a break in the bellows or the diaphragm. 2.1.9 Others Other component types can also be a source of fugitive emissions. These other types are usually small in number at a
45、facility, and they might be unique to one sector of the petroleum industry. other equipment types that are not listed above that may be considered as sources of fugitive emissions are: instruments, loading arms, stuffing boxes, site glasses, vents, dump lever arms, diaphragms, drains, hatches, meter
46、s, and polished rods. These component types can leak for a variety of reasons including improper installation, aging, deterioration, thermai stress, and vibration. 2.2 COUNTING COMPONENTS An accurate inventory of components is essential for a precise determination of fugitive emissions as well as to
47、 ensure that ail appropriate components are monitored. The first step in developing this inventory is to define the process unit boundaries. A process unit is the smallest set of process equipment that can operate independently and includes all operations necessary to achieve its process objective.
48、All of the components, by component type, need to be specified within that process unit. Components can, in some cases, be identified from process flow diagrams. However, process flow diagrams may not include all of the components that emit fugitive emissions, because all changes in the numbers of v
49、alves or connectors may not have been included on the flow diagrams. Therefore, it is usually necessary to systematically follow process streams while counting, categorizing, and labeling components as you go. Even after this systematic approach, it is recommended to divide the process unit into a grid to search for components (usually connectors) that were missed on the initiai survey. Some components will not be easily accessible. Many flanges are covered with insulation, and some components may be beyond the reach of a person on the ground. The exact definition of what is considered in
