General Purpose Steam Turbines

IPE Engineering Practice IPE-EP-6-3-1

Document number: IPE-EP-6-3-1 · Section: 6 — Rotating Equipment

The following paragraph numbers refer to API Std 611, Fourth Edition, 1997, which is part of this Engineering Practice.

INTRODUCTION

requirements for General Purpose Steam Turbines correspond to those of API Standard 611, Fourth Edition, 1997, with the specific options, deletions, additions, or modifications sanctioned in this specification. The term “Purchaser” as used in the API Standard and this specification shall be interpreted to mean the Refining Company .

The paragraph numbers in this specification correspond to those used in API Standard 611. Paragraph numbers may not be consecutive and all API paragraphs not addressed herein shall be considered to be verbatim requirements of this specification.

Instructions contained in this specification such as (add): or (substitute) shall be interpreted as follows: If information is (added) to an existing paragraph in the API Standard, the requirements of this specification shall be read as a continuation of the API paragraph. If information is (substituted), the API requirement shall be replaced in its entirety by the requirements of this specification. API paragraphs which are (revised) have specific revisions noted in this specification. If (New) is next to a paragraph number not appearing in API Standard 611, it shall be read as an added requirement.

The Purchaser’s requirements for all paragraphs in API Standard 611 which require a Purchaser’s decision (bulleted paragraphs) are indicated on the Data Sheets or in this specification. If not addressed in the inquiry, the proposal shall clearly state the basis included in the pricing furnished.

Note: U.S. customary units shall be regarded as standard. SI (metric) units in API Standard 611 and this supplement are included for convenience reference only and shall not be interpreted as precise conversions.

Table 1 records the vendor drawing and data requirements.

SCOPE

Purpose

1.1.1 (Substitute for beginning of first sentence) This specification together with the Requisition, Data Sheets, and attachments thereto, covers the minimum requirements....

1.1.3 (Add) A revision bar indicates all changes made to this Revision.

Alternative Designs

(Add) Metric fasteners and flanges constitute alternative design features and must be cited as exceptions in the vendor’s proposal.

Conflicting Requirements
(Substitute) In the event of conflict between this specification and other project documents, the order of precedence is generally as follows:
Purchase Order
Requisition Data Sheets
This specification
Referenced Industry Standards

All such conflicts shall be referred to the Purchaser in writing for resolution prior to issuance of the purchase order.

REFERENCES

Referenced Publications

2.1.2 (Substitute) Mandatory requirements cannot be superseded by any of the foregoing, and compliance therewith will be the joint responsibility of the Purchaser and the vendor. Mandatory requirements include all codes, regulations, ordinances, and/or statutes of all municipal, provincial, state and/or national bodies having jurisdiction in the location where the equipment is to be installed. It shall be the vendor’s responsibility for discernment and compliance with those mandatory requirements.

2.1.4 (New) The following Practices and Standards shall apply to the extent referenced herein or on the Data Sheets.

STANDARDS AND PUBLICATIONS

Engineering Practices
EP 5–1–1 General Piping Design EP 6–7–1 Special Requirements for Rotating Equipment EP 6–9–2 General Purpose Lube Oil Systems
API
Std 611 General Purpose Steam Turbines for Refinery Services Std 671 Special - Purpose Couplings for Refinery Service Std 677 General Purpose Gear Units for Refinery Services

BASIC DESIGN

General

4.1.4.a (Add) Use of hand valves is not permitted to operate at normal power with conincident minimum inlet and maximum outlet conditions.

(Add)

The maximum allowable noise level for each noise source shall be 85 dBA as measured three (3) feet away from the major surfaces of the unit at (5) feet above the floor level.

Where the equipment cannot meet the specified limits without the addition of a sound attenuating enclosure, the vendor shall state in the proposal the estimated levels with and without the enclosure and the basis for the estimated values.

If noise attenuating enclosures are required, the vendor shall furnish an enclosure approved by the Purchaser. The equipment shall be enclosed with instruments and piping connections on the outside of the enclosures. The enclosures shall have adequate provisions for servicing the equipment and for ventilation.

Equipment shall conform to Engineering Services Recommended Environmental Guidelines, “Noise Control Requirements”.

4.1.14 (Substitute) All equipment and auxiliaries covered by this specification shall be designed for outdoor, unsheltered installation and operation. The weather–environmental conditions are outlined in the Data Sheets. The vendor shall list in the proposal any special protective measures required or recommended.

4.2 Pressure Casings

4.2.3 (Add) All metal to metal joint faces shall be flat and free from surface defects such as dents, marring, deep or long scratches, raised metal, burrs, etc.

4.2.9 (Add) Dowel pins shall be tapered and of the threaded nut type for ease of removal.

4.2.13 Radially split turbines shall not be used to drive equipment in process hydrocarbon services, and shall be limited to turbines rated 30 HP and below.

Casing Appurtenances

(Add) All turbine casings shall be equipped with a Sentinel warning valve. Use bronze material for temperatures below 350F and steel valves for temperatures greater than 350F. In addition, a full flow pressure relief valve, per EP 5–1–1 shall be installed by the Purchaser in the exhaust piping upstream of the turbine block valve.

Casing Connections

4.4.1 (Add) Inlet and outlet connections shall be flanged. Machined and studded connections are not acceptable.

4.4.3 (Add) Unless otherwise specified, all piping connections shall be located on the lower half of the casing of a horizontally split machine. Auxiliary piping, as well as conduit, tubing, etc., shall be installed in such a manner so as to avoid attachment to or interference with the removal of the casing upper half.

4.4.3.4 (Revise) Threaded connections, except plugs, shall be seal welded. The vendor shall comply with other requirements of this APl paragraph.

4.4.3.8 (New) When a baseplate is furnished, the steam chest, steam ring, and the casing drains shall be brought out to the edge of the baseplate and terminate with flanged connections.

4.4.6.4 (Add) Flange gaskets shall be of spiral–wound metal construction, graphite filled, regardless of temperature, except for flat–faced flanges.

4.4.7 (New) Milled flange surfaces are not acceptable.

4.4.10 (New) Multi–Stage turbines shall include boroscope inspection ports between the inlet nozzle vanes and the first rotor and between each subsequent rotor and nozzle.

4.6 Rotating Elements

4.6.1 Rotors

4.6.1.3 (New) To prevent the buildup of potential damaging voltage, magnetism of any part of the rotating element shall not exceed 3 gauss (0.0003 tesla).

Seals

4.7.4 (Add) An ejector is required when the turbine is furnished with labyrinth seals or a combination of carbon ring and labyrinth gland packing.

Dynamics

4.8.2 Lateral Analysis

4.8.2.1 (Add) For multistage turbines, the turbine vendor shall perform a rotor response and lateral critical speed analysis in accordance with Appendix B. Shop verification in accordance with Section B2 is required.

4.8.3 Torsional Analysis

4.8.3.3 (Revise) Revise the last sentence to read, “the vendor shall be responsible for identifying these frequencies.”

4.9 Bearings and Bearing Housings

4.9.21 (Add) Each labyrinth seal shall include provisions enabling the connection of an air/nitrogen purge into the axial center of each labyrinth (half). Typically this consists of a drilled and tapped 1/4” diameter hole.

4.10 Lubrication

4.10.5 (Substitute) Turbines with steam supply temperatures of 400F and higher shall be supplied with circulating oil systems. The system shall meet the requirements of EP 6–9–2. Turbine oil rings may be retained if they are standard design for the bearings of the turbine.

(Add) If oil coolers are required, they shall be of the shell and tube type, TEMA–C design, with water flowing through the tubes. They shall have a steel shell; 18 BWG minimum wall, 5/8 inch minimum O.D., inhibited admiralty tubes and naval brass tube sheets furnished together with a three–way valve so that all or a portion of the oil can be bypassed around the cooler.

(Substitute for first sentence) Dual, full flow lube oil filters to filter particles exceeding 5 microns in size with a maximum clean pressure drop of 5 psi shall be provided. A suitable transfer valve shall also be provided, however, no filter bypass of any kind is permitted.

4.10.9 (Add) Capped, valved oil sample ports shall be provided at the outlet of each bearing.

Materials

General

4.11.1.3 (Modify Last Sentence) Ductile Iron is not allowed.

Castings

(Add) Major casting repairs are not permitted.

(Add) Improperly fused chaplets in iron casings may not be replaced with plugs. Iron castings with improperly fused chaplets shall not be accepted.

Welding

(Substitute) Welding of piping, pressure–containing parts, and all pressure or non–pressure parts containing dissimilar–metal welds as well as weld repairing shall be performed by operators and procedures qualified in accordance with Section VIII, Division 1 and Section IX of the ASME Code.

(Revise Last Sentence) Unless otherwise specified by the purchaser, all welding not covered by ASME codes, such as structural fabrication of baseplates, nonpressure ducting, lagging and control panels, shall be performed in accordance with AWS D1.1.

ACCESSORIES

Gear Units

(Add) Integral gear units require prior approval by the Purchaser.

(Substitute) Gears shall be of the double helical type, and shall conform to APl Standard 677.

Couplings and Guards

(Add) Dry, flexible disk couplings with restrained spacers shall be used. Flexible disk material shall be stainless steel. Spacer’s axial natural frequency shall be at least 10% higher than the maximum continous speed. Shaft couplings shall comply with APl Standard 671 for speeds in excess of 3600 RPM and/or horsepower ratings greater than 500.

Mounting Plates

5.3.1 General

5.3.1.1 (Revise) The turbine shall be baseplate mounted.

5.3.1.2.9 (Add) No more than three (3) shims shall be used in one shim pack.

5.3.1.2.12 (New) Sufficient clearance shall be provided between the case drain connection(s) and the baseplate for servicing the drain pipe and valve.

5.3.2 Baseplate

5.3.2.9 (New) Baseplate decking should be sloped and have rims to provide complete skid drainage to one or more tapped couplings. These couplings shall be 3/4” NPT minimum.

5.4 Controls and Instrumentation

5.4.2 Control Systems

5.4.2.8c (Add) The trip valve shall be of the globe type.

5.4.2.8e (Add) Pressure and moving elements shall be stainless steel.

5.4.4 Instrumentation

5.4.4.2.1 (New) Mercury type thermometers are not acceptable.

5.4.4.3 (Revise) All temperature sensors and gauges shall be mounted in thermowells.

(Add) Pressure gauges shall have a cast aluminum case.

(Revise) Delete “When specified”.

Alarms and Shutdowns

5.4.5.3.2 (Substitute) Alarm and shutdown systems shall be normally energized, deenergized to alarm or trip.

5.4.5 Vibration & Position Detectors

5.4.5.4 (New) Single stage turbines rated over 1500 HP and all multi–stage turbines shall include shaft grounding brushes which contact the rotor at the lowest possible surface speed location.

5.5 Piping and Appurtenances

5.5.1 General

5.5.1.2 (Revise Table 3) Tubing fittings shall be of Swagelok manufacture and of 316SS material. Tubing shall be of seamless, annealed 316SS material.

5.5.1.13 (New) Drains shall include a block valve as near as possible to the turbine and shall be individually piped to the edge of the baseplate, terminating in a flanged connection. The drain connections shall be clearly marked or stamped for identification.

5.5.2 Oil Piping

5.5.2.3 (New) All piping including fittings and tubing shall be of 18–8 Cr–Ni stainless steel material. Carbon steel control and block valve bodies may be used. The valve trim shall be of stainless steel material.

6.0 INSPECTION AND TESTING

Inspection

6.2.1 General

6.2.1.3 (Add) 100% visual inspection shall be performed on all parts.

Testing

6.3.3 Mechanical Running Test

6.3.3.2 (Substitute) All turbines shall be no–load tested at maximum continuous speed for a minimum of two hours after bearing and oil temperatures have stabilized. All Instrument readings shall be logged every 15 minutes.

6.3.4 Optional Tests

6.3.4.1 (Add) The vendor shall state in the proposal the capability and costs for a PTC–6 witnessed performance test to verify steam rate.

VENDOR’S DATA

General

7.1.1 (New) Data required by EP 6–7–1 shall be provided, in addition to the data required by this paragraph.

Proposals

7.2.4 (Revise) Delete “When specified”.

GUARANTEE AND WARRANTY

General

Unless exception is recorded in the vendor’s proposal, and agreed by amended specification, it shall be understood that the vendor agrees to the guarantees and warranties specified in the purchase documents and paragraph 8.2 of this Practice.

Performance Guarantee

The turbine shall be guaranteed for satisfactory mechanical performance at all opearting conditions specified on the Data Sheets and the operating range between those points. The thermodynamic performance guarantee point shall be the Normal operating point or other points indicated with “guarantee” on the Data Sheets with no positive tolerance allowed on the steam flow.

7.0 TABLES

TABLE 1 DOCUMENTATION REQUIREMENTS

FOR GENERAL PURPOSE STEAM TURBINES

PER EP 6–3–1

Item	Description	Format (1)	As–Built
1	Certified dimensional outline drawing and list of connections	See EP 2-5-2	Yes
2	Cross–sectional drawing and bill of materials	See EP 2-5-2	Yes
3	Rotor assembly drawing and bill of materials	See EP 2-5-2	Yes
4	Thrust–bearing assembly drawing and bill of materials	See EP 2-5-2	Yes
5	Journal–bearing assembly drawing and bill of materials	See EP 2-5-2	Yes
6	Packing and labyrinth drawings and bill of materials	See EP 2-5-2	Yes
7	Coupling assembly drawing and bill of materials	See EP 2-5-2	Yes
8	Gland sealing and leak–off schematic and bill of materials	See EP 2-5-2	Yes
9	Gland sealing and leak–off arrangement drawing and list of connections	See EP 2-5-2	Yes
10	Gland sealing and leak–off component drawings and data	See EP 2-5-2	Yes
11	Lube–oil schematic and bill of materials	See EP 2-5-2	Yes
12	Lube–oil arrangement drawing and list of connections	See EP 2-5-2	Yes
13	Lube–oil component drawings and data	See EP 2-5-2	Yes
14	Electrical and instrumentation schematics and bill of materials	See EP 2-5-2	Yes
15	Electrical and instrumentation arrangement and list of connections	See EP 2-5-2	Yes
16	Governor details	See EP 2-5-2	Yes
17	Steam flow versus horsepower	See EP 2-5-2	Yes
18	Steam flow versus first–stage pressure	See EP 2-5-2	Yes
19	Steam flow versus speed and efficiency	See EP 2-5-2	Yes
20	Steam flow versus thrust–bearing load	See EP 2-5-2	Yes
21	Steam correction charts	See EP 2-5-2	Yes
22	Vibration analysis data	See EP 2-5-2	Yes
23	Lateral critical analysis	See EP 2-5-2	Yes
24	Alignment diagram	See EP 2-5-2	Yes
25	Weld procedures (fabrication and repair)	See EP 2-5-2	Yes
26	Hydrostatic test logs	See EP 2-5-2	Yes
27	Mechanical running test logs	See EP 2-5-2	Yes
28	Rotor balancing logs	See EP 2-5-2	Yes

TABLE 1 (CONT.) DOCUMENTATION REQUIREMENTS

FOR GENERAL PURPOSE STEAM TURBINES PER EP 6–3–1

Item	Description	Format (1)	As–Built
29	Rotor mechanical and electrical runout	See EP 2-5-2	Yes
30	As–built data sheets	See EP 2-5-2	Yes
31	As–built dimensions and data	See EP 2-5-2	Yes
32	Installation, operation, and maintenance manuals	See EP 2-5-2	Yes
33	Spare parts recommendation and price list	See EP 2-5-2	Yes

NOTE:

(1) If the document cannot be provided in the format as indicated, the Manufacturer shall consult with the Owner’s Engineer for an acceptable alternative.

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