This paper was presented by Patrick Forgeron at the Maintenance and Reliability Technology Symposium (MARTS 2004) in Chicago, Illinois on May 25, 2004.
Equipment Diagnostic Report
Propane Delivery Pump
60P-637A
Report Date
February 18, 2004
| Table of Contents | |||
|---|---|---|---|
| 1.0 | Overall Review | ||
| 1.1 | Equipment Detail | Page 3 | |
| 1.2 | Operational Purpose & Significance | Page 3 | |
| 2.0 | Conditions Noted | Page 4 | |
| 3.0 | Oil Analysis | ||
| 3.1 | Viscosity | Page 5 | |
| 3.2 | Spectrochemical | Page 6 | |
| 3.3 | DR Ferrography | Page 7 | |
| 4.0 | Recommendations | Page 8 | |
| 5.0 | Corrective Action | Page 8 | |
| 6.0 | Oil Analysis Lab | Page 8 | |
| 7.0 | Root Cause Analysis | Page 9 | |
| 8.0 | Cost Savings | Page 10 | |
1.0 Overall Review
1.1 Equipment Detail
| Equipment No. | 60P-637A |
| Description | Propane Delivery Pump |
| Pump Mfr. | David Brown Union |
| Size | 3", QD-5240 |
| Type | Reciprocating |
| Serial No. | CA4448A501 |
| Pump Speed | 306 RPM |
| No. of Cylinders | 5 |
| Mounting | Horizontal |
| Main Bearings | 4 (2 taper roller, 2 sleeve) |
| Process Pressure | 1,440 PSIG |
| Coupling Mfr. | Gates V-Belt |
| V-Belt No. | 5VX-1800 |
| No. of Belts | 10 |
| Shaft Centerlines | 38 inches |
| Motor Sheave Dia. | 9 inches |
| Pump Sheave Dia. | 50 inches |
| Motor Mfr. | Teco Westinghouse |
| Size | 200 HP |
| Type | Variable Speed |
| Motor Speed | 1,780 RPM |
| Frame | 447T |
| Volts | 480 |
| Amps | 88 |
| Motor Bearings | NDE: 6318 DE: NU3320 |
1.2 Operational Purpose & Significance
The Propane Delivery Pump injects 8% propane into a 100% pure ethane stream at 1,440 PSIG for our customer; Enterprise requirements. Enterprise delivery requires an ethane / propane mix (EP mix) of 92% ethane and 8% propane. There are two 100%-duty pumps so one pump operates continuously. There are two conditions when we do not use the Propane Delivery Pump to inject propane into the ethane stream:
- Plant economics make it more profitable to reinject the ethane back into the pipeline (negative number)
- When Alliance Pipeline delivers a high BTU content into the plant, we are able to make up the 92/8 EP mix directly from our Demethanizer tower.
2.0 Conditions Noted
60P-637A Propane Delivery Pump - February 11, 2004:
- Both Propane Delivery Pumps; 60P-637A/B were not in service due to the high BTU content of the inlet gas from Alliance Pipeline. Typically one pump is in service under normal pipeline conditions.
- The pump No. 2 cylinder packing vent line was iced up indicating cylinder packing, leaking gas
(propane) into the low pressure flare header (see packing leak photo below). No. 2 cylinder packing was last replaced on 6/3/2002, WO-200806.
- A routine oil sample was visibly diluted and also had a very strong odor from a hydrocarbon dilution such as propane (C3).
- Oil analysis indicated abnormal component and lubricant conditions: Oil analysis report showed possible hydrocarbon contamination in the oil sample.
- Past vibration trend data did not show any significant increases. The last vibration data on this pump was collected on January 12, 2004.
Packing Leak
3.0 Oil Analysis
3.1 Oil Viscosity
60P-637A Propane Delivery Pump - February 11, 2004:
The pump lubricant oil viscosity decreased 91% from 150 to 13.5 centistokes (cSt), see oil viscosity trend plot below. The decrease in oil viscosity was caused from contamination and dilution with a hydrocarbon product.
Normal oil viscosity for Mobil SHC 629: ISO VG 150
3.0 Oil Analysis cont.
3.2 Spectrochemical Analysis
60P-637A Propane Delivery Pump - February 11, 2004:
Spectrochemical shows copper and tin wear metal content increased. Copper and tin wear metals originate from internal pump components and indicate wear. Copper wear metal content increased from 1 to 51 parts per million by weight (PPM), see trend plot below. Tin wear metals content also showed an increased from 3 to 11 PPM.
Normal wear metal content in oil is less than 15 PPM copper and 10 PPM tin.
Reciprocating pump components containing copper and tin alloys: Bearings, Wrist Pin, Bushings and Thrust Washers.
3.0 Oil Analysis cont.
3.3 Direct Reading Ferroscan
60P-637A Propane Delivery Pump - February 11, 2004:
The direct reading (DR) ferroscan indicated an increase in large and small wear particles. The high reading on the left and right side of the trend plot indicates the last two contaminated oil samples.
4.0 Recommendations
60P-637A Propane Delivery Pump - February 11, 2004:
1. Entered Work Order No. WO-400178
2. Replace pump cylinder No. 2 packing
3. Investigate possible propane gas leakage into pump oil system.
4. Drain, flush and replace pump oil with synthetic Mobil SHC 629, 10 gal capacity.
5. Increase oil sample frequency from 60 days to 30 days.
5.0 Corrective Action
60P-637A Propane Delivery Pump - February 12, 2004:
1. Maintenance changed pump cylinder No. 2 packing and all 5 crosshead pump lip seals.
2. Maintenance drained flushed and refilled pump crankcase with 10 gal. of synthetic Mobil SHC 629 oil.
3. Routine oil analysis will be monitored every 30 days.
6.0 Oil Analysis Lab
Oil analysis was performed by Analysts Inc. Data Analyst; Timothy P. Gibbons
Analysts, Inc.
ISO 9001:2000 Registered
2450 Hassell Road
Hoffman Estates, IL 60195
(800) 222-0071
7.0 Root Cause Analysis
60P-637A Propane Delivery Pump - February 12, 2004:
Possible route of entry for the propane gas into the pump crankcase is from the crosshead lip seal shown below. No. 3 crosshead lip seal showed oil leakage from the pump crankcase.
Lip Seal
8.0 Cost Savings
The following list pump parts and related costs to rebuild the pump caused from a lubrication related failure:
| Cross-head Pin (5) | $805 |
| Bearing, Connecting Rod (5) | $785 |
| Deflector, Cross-head Stub (5) | $145 |
| Bearing, Inner Race (2) | $412 |
| Bearing, Outer Race (2) | $142 |
| Shim, Crankshaft (1) | $9.00 |
| Shim, Crankshaft (1) | $8.00 |
| Shim, Cranksha ft (1) | $11.00 |
| Oil Seal, Crankshaft (1) | $39.00 |
| Oil Seal, Cross-head Stub (1) | $19.00 |
| Gasket, Crankshaft Cover (1) | $16.00 |
| Gasket, Crankcase Inspection Cover (1) | $18.00 |
| Labor Costs (2 x 24 x $50) | $2,400 |
| Total Potential Cost Savings............................ | $4,809 per failure x 4 = $19,236 |
The above cost analysis assumes the connecting rods were reused, if connecting rods were damaged they would cost an additional $882 each x 5 cylinders = $4,410 per failure.
Analysts Inc. oil analysis has detected a decrease in oil viscosity on 60P-637A and B pumps on four occasions. The oil was replaced with no interruption in production and no internal pump repairs. The cost for replacing the synthetic oil was $80.00 per occurrence.
| Date | Work Order No. | Oil Viscosity cSt |
|---|---|---|
| June 25, 2002 | WO-200869 | 19.4 |
| December 2, 2003 | WO-301516 | 123 |
| February 11, 2004 | WO-400178 | 13.5 |
| February 11, 2004 | WO-400216 | 89 |
Summary:
Oil analysis, should be implemented with established goals, expectations and requirements of the user. In conjunction with solid communication and cooperative working with a qualified laboratory the program will provide extraordinary returns on the invested resources utilized to manage the program.
With a very low cost of program implementation and ongoing costs a successful oil analysis program will provide significant information to maintenance and reliability managers on the condition of the oil wetted components and lubricants from critical equipment in use in their operations. Information that identifies wear related problems, contamination and changes in lubricant quality that will effect equipment performance. Reaction to this information and follow-up on the recommended maintenance activities will result in increased uptime, lower cost of operation and reduced & delayed capital outlays for equipment replacement.
Presented By:
Patrick Forgeron
Analysts, Inc.
800-336-3637
Pforgeron@analystsinc.com
www.analystsinc.com
