Energy efficiencies and CO2 emissions associated with low-temperature separation technologies for the processing of formation fluid from the Achimov deposits

Abstract

Three different technologies for the low-temperature separation (LTS) of gas condensate from the Achimov deposits in the Russian Urengoyskoe gas and condensate field were assessed using exergy analyses. The options examined included turbo-expansion and ejection. Thermomechanical exergy values were calculated for material streams and exergy losses and efficiencies were estimated for dedicated equipment used in the LTS. The lowest exergy loss of 4221.2 kW was obtained using turbo-expansion and electricity cogeneration. The carbon release associated with each scenario was calculated while considering different production rates, technological parameters and natural decreases in wellhead pressure. The integral carbon footprint after 40 years of LTS operation was estimated for all cases. A classical ejector-based LTS scheme was shown to produce 1200 t of CO₂ emissions over 40 years of operation. This same scheme combined with a turboexpander and electricity generator produced 59% less CO₂ in the same period. An expansion-cogeneration LTS scheme was found to be the most effective and ecologically friendly among the various options based on this analysis.