1、 Ageing rotating equipment Guide for maintenance and operation PUBLICATION 230 Edition 1 RELEASED BY IHS. NOT FOR RESALE THE ENGINEERING EQUIPMENT AND MATERIALS USERS ASSOCIATION Ageing rotating equipment Guide for maintenance and operation PUBLICATION 230 Edition 1 Copyright 2014 The Engineering Eq
2、uipment and Materials Users Association. A company limited by guarantee. Registered in England. Company number 477838. ISBN 978-0-85931-194-6 Imprint reference 04-2014 Registered and Trading Address 63 Mark Lane London EC3R 7NQ Telephone: +44 (0)20 7488 0801 Fax: +44 (0)20 7488 3499 E-mail: saleseem
3、ua.org Website: www.eemua.orgEEMUA Publication 230 Ageing rotating equipment - Guide for maintenance and operation EEMUA ii ENGINEERING EQUIPMENT AND MATERIALS USERS ASSOCIATION About EEMUA The Engineering Equipment and Materials Users Association is usually known by its initials, EEMUA. EEMUA is an
4、 Association established by the owners and operators of industrial assets. Any organisation that is a substantial user or substantial purchaser of engineering products is eligible to apply to become a member of EEMUA. Membership is subject to the approval of Council. EEMUA Aims EEMUA aims to improve
5、 the safety, environmental and operating performance of industrial facilities in the most cost-effective way, pursuing and promoting leadership in industrial asset management by sharing engineering experiences and expertise, and by the active, enlightened promotion of the distinct interests of users
6、 of engineering products. These aims are achieved by various means, including: Providing the organisation within which networking, information sharing and collaboration among users on non-competitive technical matters can take place Influencing the way written regulations are interpreted and applied
7、 in practice Promoting and presenting members views, and encouraging the application of good sound engineering practices Developing user guides, specifications, training and competency schemes Facilitating members participation in national and international standards making Influencing relevant nati
8、onal and European legislation and regulation. The income and resources of EEMUA are applied solely towards the promotion of the aims of the Association. No profit is transferred by way of dividend, bonus or otherwise to members. The work of the Association is mainly carried out by members representa
9、tives on EEMUA Technical Committees, Working Groups, and Forums, supported by EEMUA staff. Incorporation, Membership and Other Information For the purposes of conducting its business, EEMUA is incorporated in England and Wales as a company, limited by guarantee, not having share capital. All usual a
10、spects of company management and business administration are dealt with through the EEMUA Chief Executive, including policy implementation and leadership of the Executive team (the staff). A list of EEMUA publications for sale is given at the end of this Publication. The full list is also on the Ass
11、ociations website, including details of on-line shopping facilities. To enquire about corporate Membership, write to enquirieseemua.org or call +44 (0)20 7488 0801. EEMUA Publication 230 Ageing rotating equipment - Guide for maintenance and operation EEMUA iii ABOUT THIS PUBLICATION Legal Aspects Al
12、l rights, title and interest in this Publication belong to EEMUA. All rights are 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 other, without the express prior writ
13、ten agreement of the EEMUA Chief Executive. Infringement of copyright is illegal and also reduces the Associations income thereby jeopardising its ability to fund the production of future publications. It has been assumed in the preparation of this Publication that: the user ensures selection of tho
14、se parts of its contents appropriate to the intended application; and that such selection and application is correctly carried out by appropriately qualified and competent persons for whose guidance this Publication has been prepared. EEMUA and the individual members of the Work Group that prepared
15、this EEMUA Publication do not, and indeed cannot, make any representation or give any warranty or guarantee in connection with material contained herein. EEMUA and the individual members of the Work Group that prepared this EEMUA Publication expressly disclaim any liability or responsibility for dam
16、age or loss resulting from the use or reliance on this Publication. Any recommendations contained herein are based on the most authoritative information available at the time of writing and on current good engineering practice, but it is essential for the user to take account of pertinent subsequent
17、 developments and/or legislation. Any person who encounters an inaccuracy or ambiguity when making use of this Publication is asked to notify EEMUA without delay so that the matter may be investigated and appropriate action taken. Consultation and Feedback EEMUA encourages constructive comments on t
18、his Publication from both Members of the Association and others. Comments should be sent on the standard feedback form, a copy of which is provided towards the end of this Publication. An electronic version of the feedback form is available from EEMUA - e-mail your request for a copy to enquirieseem
19、ua.org, telephone your request to +44 (0)20 7488 0801, or download the form from the EEMUA website at www.eemua.org. Submit comments by e-mail (preferred) or post. Comments are considered by the relevant EEMUA Technical Committees and may be incorporated in future editions of this Publication. New e
20、ditions are publicised on the EEMUA website. EEMUA Publication 230 Ageing rotating equipment - Guide for maintenance and operation EEMUA iv Table of Contents 1. Introduction 1 2. Scope 3 3. Guidance . 5 3.1 Introduction 5 3.2 Mechanical deterioration mechanisms . 5 3.2.1 External corrosion 5 3.2.2 I
21、nternal corrosion 6 3.2.3 Stress Corrosion Cracking (SCC) 7 3.2.4 Fretting corrosion . 8 3.2.5 Erosion . 8 3.2.6 Fatigue . 9 3.2.7 Creep . 11 3.2.8 Stress relaxation 12 3.2.9 Hydrogen embrittlement . 12 3.2.10 Liquid Metal Embrittlement (LME) . 12 3.2.11 Brittle fracture . 13 3.2.12 Excessive extern
22、al loads . 13 3.2.13 Failure of supports . 13 3.2.14 Accidental damage . 14 3.2.15 Internal wear . 14 3.3 General deterioration mechanisms The maintenance programme includes inspections, scheduled either by time/running hours or by the condition of the machinery; Condition monitoring is being carrie
23、d out including regular vibration monitoring as a minimum; Routine inspection/testing of machine protective systems (such as trips / trip valve operation / relief valves) is being carried out. As well as additional inspections, replacement of part or the entire machine may be necessary or simply adv
24、isable. The guide aims to highlight where a review of upgrade and replacement options may be beneficial. A large topic that is not covered in this document is the initial design of rotating mechanical equipment, which is assumed to be correct, or to have been dealt with during commissioning or in th
25、e first few years of operation. This Publication does not describe repairs or reclamation necessary as a result of failures in service. Such failures may cause serious damage to the machine and may threaten its continued long term operation. Some topics are included in this guide that are not relate
26、d to machine failures, e.g. the change in regulatory requirements and the changes in instrumented machine protection.EEMUA Publication 230 Ageing rotating equipment - Guide for maintenance and operation EEMUA 4 EEMUA Publication 230 Ageing rotating equipment - Guide for maintenance and operation EEM
27、UA 5 3. Guidance 3.1 Introduction This Chapter is set out to firstly describe the various deterioration mechanisms that are relevant for process plant machinery and then the mitigation steps that may be taken for that particular deterioration mechanism. Clearly, some of the deterioration mechanisms
28、will apply to many types of equipment, whereas others only apply to certain types of machine. In some cases there may be reasons for equipment to be replaced completely and these are listed. A list of the various types of process plant machinery is then given with a cross reference to the types of d
29、eterioration mechanisms that apply (see Table 1). 3.2 Mechanical deterioration mechanisms From the Pressure Systems Safety Regulations 2000 Approved Code of Practice L122(1)paragraph 110, there are a number of mechanical deterioration mechanisms, which are described in this Section with specific app
30、lication to rotating equipment. Specific mitigation steps are listed for each deterioration mechanism. Clearly, a general mitigation is to put in place appropriate inspection to identify problems and allow for rectification. Note: As routine inspection/repair is assumed to be taking place it is not
31、specifically listed against the deterioration mechanisms described in this section. 3.2.1 External corrosion External corrosion is typically due to atmospheric oxidation of the metallic components of the machine, and is applicable mostly to carbon steel operating near ambient temperatures (0C - 80C)
32、 where water can be present. It is made worse where the equipment is insulated as the insulation can trap moisture next to the surface of the casing. Other factors that can increase the rate of external corrosion are the local atmospheric conditions, including: Steam leaks; Process leaks of acidic g
33、ases or liquids or corrosive materials such as salt/brine; Local ambient conditions (temperature, humidity and salt content of the air). High temperature external corrosion may be an issue if the temperature exceeds 400C for susceptible materials. Machine casings are often of a standard design and a
34、lso are designed for stiffness rather than for the pressure that is being contained. The result of this is that in most cases, the design maximum operating pressure is well above the actual service conditions, so it is unlikely that external corrosion will threaten the reliable operation of equipmen
35、t. EEMUA Publication 230 Ageing rotating equipment - Guide for maintenance and operation EEMUA 6 The areas which are most susceptible to external corrosion and the anticipated effects are: Small bore branch connections in carbon steel o pin hole leaks; Low pressure carbon steel equipment housings (s
36、uch as fans or ducts) o pin hole leaks; o potential for large areas of corrosion leading to structural failure Structural support steelwork; o potential for structural failure/support failure and major equipment damage. Specific mitigation steps are: Correct specification, application and maintenanc
37、e of protective systems such as paint; Avoidance of process/steam leaks; Correct specification, installation and maintenance of insulation to avoid water ingress; Correct specification, installation and maintenance of pipe supports/structural supports. 3.2.2 Internal corrosion Internal corrosion req
38、uires a corrosive environment to be present inside the machine. For most applications, this requires free water to be present in the presence of acidic species. Where high internal temperatures (greater than 500C) are present then dry oxidation can take place. In some cases corrosion is affected by
39、the fluid flow to produce metal loss in high flow velocity regions. Process plant applications do not normally suffer from significant internal corrosion as the materials are selected to avoid deterioration. However, there can be exceptions, which include: Gas turbine inlet internal corrosion due to
40、 water/salty atmosphere/high temperatures; Small quantities of water present in a gas compressor drying out and then re-condensing. As the liquid re-condenses any acidic species in the gas will become highly concentrated and corrosive. Water carry over in an air compressor/gas compressor intercooler
41、 knock out system causing corrosion of carbon steel components. For an air compressor this can be made worse where the air inlet is in an industrial area such that acidic species can be concentrated in the condensate water. Fluid flow disturbing the protective film on the metal surface (e.g. oxide l
42、ayer) resulting in material loss. An example of this is in a boiler feed water pump in high flow velocity regions (e.g. casing outlet nozzle) where gross local metal loss has been seen after 20 years in service. Machine systems shut down allowing internal condensation and standing water. This also a
43、pplies to bearing systems where atmospheric breathing can cause internal water accumulation and subsequent corrosion. Dissimilar metals corrosion, e.g. aluminium labyrinth corrosion in a steel casing; Under deposit corrosion in a wet gas centrifugal compressor; Cooling water pumps internal corrosion
44、 following coating breakdown; EEMUA Publication 230 Ageing rotating equipment - Guide for maintenance and operation EEMUA 7 Induced draft fan impellers on fans that do not run continuously have been found with corrosion to the impeller attachment bolting. This threatens impeller integrity due to air
45、 leaks at rotor seals causing local dew point corrosion to shafts and impellers. Gross failure of a large fan is likely to be a significant safety concern as the casing is unlikely to contain the failed parts, which will then be ejected from the machine. Corrosion in cooling water areas of reciproca
46、ting compressor cylinders. This is often made worse due to the low cooling water velocities within the cylinder cooling water channels, which leads to silt lay down and then under deposit corrosion. Machine casings are often of a standard design and are designed for stiffness rather than for the pre
47、ssure that is being contained. The result of this is that in many cases, the design maximum operating pressure is well above the actual service conditions, so it is unlikely that internal corrosion will threaten the reliable operation of equipment. Specific mitigation steps are: Monitoring internal
48、system pH; Preservation steps during periods of extended downtime; Repair/maintenance of internal coating; Dry instrument air/nitrogen purging of bearing housing systems; Use of purge mist lubrication systems for the bearing housing; Use of anti-condensation heaters; Correct cooling water treatment/
49、chemistry; A maintenance regime that cleans out cooling water deposits regularly. 3.2.3 Stress Corrosion Cracking (SCC) Stress Corrosion Cracking (SCC) can be caused by a number of different agents, such as sulphides, chlorides, nitrates and hydrogen. Correct initial selection of materials of construction should avoid problems with SCC during the life of the equipment. However, external effects can occur later in the life of the equipment, either with chlorides (typically from sea w
