ENG. ANDREW OMWENGA

Operating Challenge: Severe asphaltene precipitation and colloidal deposition in an atmospheric crude distillation preheat train caused overall heat transfer coefficients (U-values) to degrade from 420 W/m²·K to under 180 W/m²·K over a 9-month cycle. This forced the fired heater duty up by 5.8 MW, creating thermal bottlenecks and elevated fuel gas consumption.

Engineering Solution: Built a dynamic Aspen HYSYS and Aspen EDR digital twin integrated with a custom Python Ebert-Panchal threshold fouling model. Optimized stream velocity distribution and bypass valves to keep film temperatures below the threshold fouling onset line while maintaining target column inlet temperature (360°C).

Operating Challenge: Traditional blast furnace ironmaking emits approximately 1.8 to 2.2 tonnes of CO2 per tonne of liquid iron. Transitioning an industrial plant to 100% green hydrogen DRI required resolving strong endothermic cooling effects inside the shaft furnace that risked freezing the reduction bed.

Engineering Solution: Developed a multi-stage Gibbs reactor and kinetic plug-flow reactor model in Aspen Plus to evaluate 5 transition scenarios (0% to 100% H2 blend). Designed a recirculating shaft gas preheating loop and top gas recycling system that preserved bed metallization above 94% while slashing Scope 1 carbon intensity to near-zero.

Operating Challenge: Continuous flaring of low-pressure sour casinghead and relief gas wasted valuable heavy hydrocarbons (C3+) and generated extensive carbon emission fines and flaring penalties.

Engineering Solution: Designed a liquid-ring compressor boosting train followed by amine sweetening (MDEA) and a cryogenic turboexpander refrigeration unit. The system captures and fractionates high-value LPG (propane/butane) and stabilized condensate while recycling clean fuel gas back into plant boilers.

Operating Challenge: High thermal steam consumption (12.4 t/h of 4 barg steam) across wort boiling and evaporator sections created high operating fuel costs and localized thermal effluent disposal issues.

Engineering Solution: Executed a full composite curve Pinch Analysis. Designed a Mechanical Vapour Recompression (MVR) system with a centrifugal steam compressor and integrated secondary plate-and-frame condensing recuperators, capturing latent heat of vapor and transferring it to incoming mash liquor.