ToolFusion
📋 Case Study

Olkaria IV Reinjection Heat Recovery Project – Kenya

Extremely low ΔT (<15°C) requiring ultra-low pinch design; aggressive chloride corrosion from NaCl-rich reinjection water; remote location limiting spare parts logistics

🏗️ Project Overview

Installation of 2.1 MW low-temperature ORC (R1233zd(E)) downstream of 72°C reinjection line to recover residual heat before subsurface disposal

🎯 Challenge

Extremely low ΔT (<15°C) requiring ultra-low pinch design; aggressive chloride corrosion from NaCl-rich reinjection water; remote location limiting spare parts logistics

🔧 Design Approach

Microchannel titanium-alloy HX with 1.2 mm hydraulic diameter; single-stage radial-inflow expander with ceramic-coated shaft; cloud-based remote diagnostics with predictive failure alerts

📐 Design Diagram

MicrochannelTi-alloy HXOlkaria IV Reinjection Heat RecoveryRadialExpander(Ceramic shaft)Cloud DiagnosticsPredictive AlertsΔT_pinch = 3.1°C(Ultra-low pinch)CR = 0.018 mm/yr(Cl⁻ corrosion)Remote location →Spare parts logistics challengeHydraulic diameter:dₕ = 1.2 mmReinjection water flow →Wellfield condensate ←

AI-generated project design illustration

📐 Key Calculations

Minimum Pinch Temperature

ΔT_pinch = T_reinject_in − T_wf_cond
Result: 3.1°C
Enabled feasible heat recovery at 72°C source

Corrosion Rate Estimate

CR = A·exp(−E_a/RT)·[Cl⁻]^n
Result: 0.018 mm/yr
Confirmed titanium alloy suitability per NACE MR0175/ISO 15156

📊 Results

Operational since 2021 with >94% availability; measured 11.2% net efficiency; zero unscheduled shutdowns; remote diagnostics reduced mean time to repair (MTTR) by 67%

💡 Lessons Learned

  • •Microchannel HXs enable economically viable ultra-low-ΔT recovery
  • •Predictive alerts based on vibration + temperature gradient trends cut MTTR dramatically
  • •Titanium microchannels justified CAPEX premium via 12-year design life vs. 5-year for SS316

✅ Key Takeaways

  • 1Microchannel HXs enable economically viable ultra-low-ΔT recovery
  • 2Predictive alerts based on vibration + temperature gradient trends cut MTTR dramatically
  • 3Titanium microchannels justified CAPEX premium via 12-year design life vs. 5-year for SS316