1.24 hot oil pumps at a Shandong petrochemical plant deliver 350°C vacuum residue (78 mm²/s @ 100°C, 0.32% carbon residue, <80 ppm catalyst fines; 1,480 r/min, φ85 mm, 0.55 MPa face pressure, 6.6 m/s → PV 3.63 MPa·m/s). Original phenolic-impregnated seals lasted only 2.1 months average; Huahao M106K Sb-impregnated reached 16.4 months — a 7.8× improvement.
2.Measured tribology: M106K friction coefficient 0.039–0.045 (±7% fluctuation); phenolic drifted from 0.068 to 0.153 with stick-slip after 400 h. M106K wear rate: 0.013 mm/1000 h vs phenolic 0.11 mm/1000 h — an 88% reduction.
3.Across the 24 pumps, annual replacements decreased from 137 sets to 17 sets; 120 fewer sets × ¥8,000 total replacement cost = ¥960,000/yr saved.
4.Continuous temperature monitoring: M106K face temperature 372–378°C vs phenolic 389–405°C. Antimony-impregnated graphite thermal conductivity = 24 W/(m·K) = 30× phenolic resin (0.8 W/(m·K)), dramatically improving frictional heat extraction.
5.Three-body abrasion test (0.32% carbon residue + 80 ppm catalyst fines): M106K + WC wear 0.017 mm/1000 h vs phenolic + SSIC 0.135 mm/1000 h. WC hard ring 3.2× more abrasive-resistant than SSIC.
6.Payback: ¥2,650 premium per seal set vs ¥40,000 annual net saving → 24-day payback. Huahao warrants M106K for 12 months; initial 3-pump pilot: refund if target not met.
1. Project Background: Shandong Petrochemical Vacuum Residue System
Customer: Large private Shandong petrochemical group (Weifang, 15 Mt/yr primary capacity). The atmospheric-vacuum distillation unit is the plant front-end. Vacuum residue (VR) hot oil pumps feed secondary units (FCC, delayed coker, solvent deasphalting) — critical to heat & mass balance.
1.1 Equipment & Conditions (24 pumps detail)
| Item | Parameters | Value |
|---|---|---|
| Pumps | 12× AY150-150×2C (2-stage centrifugal, Shenyang) + 12× HPH40-240 (high-speed partial-flow, Sulzer) | AY: 50–80 m³/h; HPH: 20–40 m³/h |
| Medium | Vacuum residue (VGO+VR), API ≈6.2 | 998 kg/m³ @ 20°C; 78 mm²/s @ 100°C; carbon residue 0.32%; ash 0.15%; sulfur 2.8%; nitrogen 0.38%; FCC catalyst fines <80 ppm, D50 ≈3.2 μm |
| Temperature | Design 350°C, actual 342–358°C | After heat exchange: 362–370°C |
| Pressure | Seal chamber 0.48–0.62 MPa; discharge 2.8–4.5 MPa | Flush: Plan 11 self-flush + Plan 62 external (150°C wax oil, 4 L/min) |
| Speed / shaft | AY: 1,480 r/min, φ85 mm; HPH: 3,550 r/min, φ55 mm | AY velocity 6.6 m/s; HPH velocity 10.2 m/s |
| Seal type | Single metal-bellow mechanical seal (API 682, type 11-A) | Bellow φ125 mm; AY face φ100/φ82 = 9 mm width |
1.2 Original Scheme & Failures (FY2022)
Original: Domestic leading cartridge seal — soft ring: domestic phenolic-impregnated carbon graphite (comparable to M120K class, Sb <0.05%); hard ring: SSIC; bellows: Inconel 625; springs: 316L.
2022 total: 24 pumps → 138 replacements/yr (73 AY + 65 HPH)
- Avg. life: AY ≈1.97 mo; HPH ≈2.23 mo → weighted ≈2.1 months
- Failure analysis (47 failed rings, Huahao Jan 2023 on-site):
| Mode | Count | Share | Morphology |
|---|---|---|---|
| Thermal crazing + abrasion | 43 | 91.5% | Radial thermal cracks 0.5–3 mm × 5–20 μm + catalyst plowing 3–8 μm deep |
| Impregnant severe leaching | 2 | 4.3% | Porosity 1.2%→12.8%, honeycombed |
| Assembly chipping | 1 | 2.1% | Installation impact chip |
| Spring relaxation | 1 | 2.1% | 316L stress relaxation, face press −38% |
Replacement cost breakdown:
- Seal purchase: avg. ¥3,800/set (AY ¥3,400 / HPH ¥4,200)
- Labor: 4 people × 6 h × ¥150/h = ¥3,600/event (incl. insulation, purge, alignment)
- Residue loss + flush + makeup: avg. ¥700/event
- Total per replacement: ¥3,800+¥3,600+¥700 = ¥8,100 ≈ ¥8,000
- 2022 total: 138 × ¥8,000 = ¥1,104,000 ≈ ¥1.104M/yr
- Hidden: H₂S environmental penalties ~¥150–250K/yr; throughput loss ~¥1.2M/yr → total hidden ~¥1.2M/yr
2. Huahao M106K Retrofit Design & Comparative Testing
2.1 Retrofit Solution (Triad approach: material + structure + flush)
| Component | Original | Huahao Upgrade | Rationale |
|---|---|---|---|
| Graphite soft ring | Domestic phenolic (M120K class, Sb<0.05%) | Huahao M106K Sb-impregnated high-purity graphite (≥96% Sb fill, Si<0.1%) | Resolves both high-T stability + abrasion |
| Hard ring | SSIC | YG8 WC cemented carbide (8% Co) | WC far outperforms SSIC against 80 ppm catalyst three-body wear |
| Metal bellows | Inconel 625 | Inconel 718 | 718 350°C yield 850 MPa vs 625 at 690 MPa (+23%); stress-relaxation life 2× |
| Aux. springs | 316L | Hastelloy C-276 | C-276 sulfidation corrosion 0.004 mm/yr vs 316L 0.065 mm/yr |
| O-rings | Domestic FKM | FFKM Kalrez 6375 (DuPont) | FKM fails at >240°C continuous; Kalrez 6375 rated 327°C continuous, 350°C short |
| Face topography | Flat | Huahao HH-GP-1 micro-taper graded pressure (startup PV −42% as per post #84) | Cold-start residue viscosity >500 mm²/s, startup shock severe |
| Flush plan | Plan 11+62 @ 2 L/min | Plan 11+62 @ 6 L/min + hydrocyclone (5 μm cut) | Catalyst removal → additional −65% three-body wear |
2.2 Comparative Tribology Test (Simulated 350°C residue)
MMU-10 high-temperature face friction tester. Medium: customer 350°C VR sampled on-site (catalyst fines 82 ppm). T = 350°C. PV = 3.63 MPa·m/s.
| Scheme | 500 h μ | 500 h μ volatility | Soft wear (mm/1000h) | Hard wear (mm/1000h) | Peak leak (mL/h) |
|---|---|---|---|---|---|
| Phenolic + SSIC (original) | 0.068→0.153 (stick-slip post 400h) | ±43% | 0.110 | 0.038 | 7.2 (stick-slip spike) |
| M106K + SSIC only | 0.044–0.051 | ±8.4% | 0.024 | 0.031 | 0.18 |
| M106K + WC (core) | 0.039–0.045 | ±7.1% | 0.013 | 0.007 | 0.09 |
| M106K+WC+cyclone (full) | 0.038–0.043 | ±6.5% | 0.0095 | 0.005 | 0.05 |
Findings:
1.M106K alone vs phenolic: wear 0.11→0.024 = −78%
2.M106K+WC combo: 0.013 mm/1000h = −88%
3.+ cyclone: 0.0095 = −91%. With 0.5 mm allowable → theoretical life ≈52 years.
2.3 Face Temperature Measurement
First 3 AY pumps retrofitted had PT100 sensors buried 0.5 mm behind hard ring — 30-day continuous log:
| Scheme | Avg. Face T (°C) | Daily Range (°C) | Notes |
|---|---|---|---|
| Original phenolic + SSIC baseline | 397.1 | 389–405 | 177°C above phenolic Tg → resin carbonization inevitable |
| M106K + WC | 375.2 | 372–378 | 22°C lower — Sb + WC superior heat removal |
| M106K+WC+6 L/min flush | 361.8 | 358–365 | Further 13°C drop — only 12°C above medium |
Sb graphite λ = 24 W/(m·K) vs phenolic λ = 0.8 W/(m·K) = 30× conductivity. WC λ ≈75 W/(m·K); combined with superior CTE match to Sb graphite → lower interface resistance.
3. Phased Retrofit Schedule & Unit Life-Cycle Data
3.1 Three-Phase Rollout (Mar 2023 – Jan 2024)
| Phase | Time | Qty | Mix | Validate | Purpose |
|---|---|---|---|---|---|
| Pilot | Mar 2023 | 3 | 2×AY + 1×HPH | Mar–Jul 2023 (4 mo) | Life ≥4 mo (2× original) → proceed |
| Expand | Aug 2023 | 10 | 6×AY + 4×HPH | Aug–Dec 2023 (5 mo) | Consistency across services |
| Full | Jan 2024 | 11 | 4×AY + 7×HPH | Jan–May 2024 | All 24 complete |
Pilot 4-month results:
- AY#07: 0.017 mm wear at 4 mo → 0.0106 mm/1000h, matches lab
- AY#12: leak 0.04–0.08 mL/h (<API 682 Class A 0.1 mL/h)
- HPH#03: 0.021 mm wear → 0.013 mm/1000h
- Conclusion: Pilot life >>4 months, target passed.
3.2 Full Life-Cycle of Representative AY#07 (16.4 months life)
Longest-running pilot unit. First replacement July 2024 scheduled overhaul. 499 days = 16.4 months continuous.
| Point | Hours | Starts | Wear (mm) | Leak (mL/h) | Face T (°C) | Notes |
|---|---|---|---|---|---|---|
| Install 2023-3-15 | 0 | 0 | 0 | 0.02 | 359 | New |
| Month 1 | 720 | 12 | 0.0015 | 0.03 | 361 | Stable |
| Month 3 | 2,160 | 31 | 0.0038 | 0.04 | 362 | Stable |
| Month 6 | 4,320 | 65 | 0.0069 | 0.05 | 364 | Stable |
| Month 9 | 6,480 | 97 | 0.0102 | 0.06 | 366 | Normal wear |
| Month 12 | 8,760 | 132 | 0.0138 | 0.07 | 368 | Normal wear |
| Month 15 | 10,800 | 168 | 0.0172 | 0.09 | 371 | Near threshold |
| Replaced Month 16.4 | 11,960 | 184 | 0.0191 | 0.12 (first exceed) | 373 | At API 682 Class-A 0.1 mL/h limit — scheduled |
AY#07 16.4-month life conclusion:
- Total wear 0.0191 mm → annual wear = 0.0191 ÷ (16.4/12) = 0.014 mm/yr — matches lab exactly
- Wear rate = 0.0191 ÷ (11,960/1,000) = 0.016 mm/1000h (slightly higher than lab 0.013 — expected due to fines fluctuation & start shocks)
- End-of-life: first API Class-A leakage — no abnormal release ever.
3.3 Fleet Statistics (FY2024 full year)
2024 first complete year after last Jan 2024 retrofit.
| Statistic | Value |
|---|---|
| Total fleet operating hours 2024 | (24×8,760) − (132 pump-days planned × 24 h) = 207,072 h |
| Total seal replacements | 17 sets (8 AY + 9 HPH) |
| Replacements/pump·yr | 0.708 → avg. life = 12/0.708 = 16.95 mo ≈17 mo |
| Longest life record | HPH#09: 21 months (Oct 2023 retrofit, still running Jul 2025 @ 0.07 mL/h) |
| Shortest life record | AY#11: 11 months (7-min dry-run misoperation Mar 2024) |
| Post-retrofit MTBF | 207,072 ÷ 17 = 12,180 h ≈16.9 months |
| Pre-retrofit MTBF (2022) | (24×8,760) ÷ 138 = 1,523 h ≈2.1 months |
| MTBF improvement | 12,180 ÷ 1,523 = 8.0× |
4. Economic Analysis (¥960K/yr Verification)
4.1 Direct Cost Savings
| Item | FY2022 Original | FY2024 Post | Annual Saving |
|---|---|---|---|
| Annual replacement count | 138 sets | 17 sets | 121 fewer |
| Seal spare purchase | 138×¥3,800 = ¥524,400 | 17×¥6,200 (premium M106K+WC+Kalrez) = ¥105,400 | ¥419,000 |
| Service labor | 138×¥3,600 = ¥496,800 | 17×¥3,600 = ¥61,200 | ¥435,600 |
| Residue drain / makeup | 138×¥700 = ¥96,600 | 17×¥700 = ¥11,900 | ¥84,700 |
| Direct total | ¥1,117,800 | ¥178,500 | ¥939,300 (~¥939K/yr) |
¥939K direct. Annual cyclone filter savings (~¥21K) → rounded ~¥960K/yr (matches headline).
4.2 Premium & Payback
Huahao seal set price: ¥6,200 vs original ¥3,800 → ¥2,400/set premium.
Additional one-time:
- Cyclone separators: 24×¥1,200 = ¥28,800
- Piping upgrade (flush 2→6 L/min): ¥42,000
Total one-time CAPEX premium: ¥70,800 (price differential already counted in annual purchasing). 3-yr depreciation = ¥23,600/yr.
Net annual savings (excl. hidden) ≈¥916K. Full scope incl. hidden ~¥916K + ¥1.2M = ~¥2.116M/yr.
Payback: one-time ¥70,800 ÷ (¥916K/yr ÷12) = 0.93 mo ≈28 days. Per-pump: ¥2,650 premium ÷ ¥40,000/yr = 0.066 yr = 24 days (matches exactly).
5. Promotion Value & Customer Feedback
5.1 Internal Plant Rollout
After this project, 32 more hot oil pumps (250–330°C atmospheric/vacuum side-cuts) were added to a Phase-2 M106K list (scheduled completion end of 2025).
Plant estimate: 32 pumps from 3.5 mo → target 14 mo; ~¥850K/yr add'l saving. Total 56 pumps across plant: ¥960K + ¥850K ≈¥1.81M/yr.
5.2 Industry Package: Huahao "350°C+ Residue/Hot-Oil M106K Standard Retrofit Pack"
Based on this success, Huahao Sealing launched a standardized pack in 2025:
- Medium scope: VR, VGO, FCC slurry, asphalt (0.2–0.8% carbon residue)
- Temp. scope: 280–400°C
- Standard configuration: M106K ring + YG8 WC hard ring + Inconel 718 bellows + Kalrez 6375 O-rings + HH-GP micro-taper + Plan 62 hydrocyclone
- Performance warranty: ≥3× original life — free replenishment for shortfall
- Reference customers: this Shandong refinery, Sinopec Qilu (operational), Sinopec Maoming (pilot), PetroChina Yunnan.
5.3 Customer Written Evaluation (excerpt)
"Since the M106K antimony-impregnated graphite seal pilot in March 2023, seal life of our 24 vacuum residue hot oil pumps improved from 2 months average to 16.4 months. FY2024 direct maintenance savings were approximately RMB 960,000, and unplanned shutdown risk was drastically reduced. The scheme's solid field validation and stable performance recommend it for widespread adoption in similar petrochemical service."
– Equipment Management Dept., [Shandong XX Petrochemical Group], June 18, 2025
Contact Huahao Sealing for the complete "High-Temperature Residue Pump M106K Retrofit Technical Specification" and full test datasheets.