Power control of PV and grid-assisted CAES system integrated into SONATRACH LPG SP1 ELR1 pumping station with thermal energy recovery from flared LPG

Abstract

The Algerian National Company for the Transport and Marketing of Hydrocarbons (SONATRACH) provides crude oil, natural gas, condensate, and liquefied petroleum gas (LPG), which recorded an average invoiced electricity consumption of 1.3 M$/yr from 2017 to 2022 for Region of Transport Haoud El-Hamra (RTH) alone. LPG SP1 ELR1 (Pumping Station 1 of Expansion Line 1 at Alrar-Hassi R’mel), as one of the RTH pumping stations, indicated a considerable electricity supply through three 220 KV overhead electrical lines, reduced to 5.5 KV using the transformers to ensure a station input power of around 4.5 MW, representing a loss of 21 % of annual consumption. However, the input power is never fully utilized by the station and paid on average 391.6 K$/yr added to equipping the station with transformers at an extra cost of 1.78 M$ and the power outages from the grid resulting in significant losses of 105.6 K$/h in pumped LPG sales. This paper presents the first process study of a photovoltaic (PV) and electrical grid-assisted Compressed Air Energy Storage (CAES) system integrated into the LPG SP1 ELR1 with the flared LPG recovery to achieve electrical independence, and it includes a system analysis on process optimization, cost, and environmental impact. The study discusses a combination of PV, electrical grid, and, in particular, the CAES process simulated using ASPEN HYSYS software to control its output power, including three scenarios: without air thermal energy recovery (ATER), with ATER, and with LPG thermal energy recovery (LPG-TER). According to the results, the CAES with LPG-TER demonstrated a more than 100 % increase in power delivery, corresponding to approximately 10 MW of generated power compared to input power of 4.5 MW, thus exceeding the needs of the pumping station by two times. In addition, the comparison with the literature-mentioned competing systems underscores the system's superiority, with a 32 %, 55 %, and 66–68 % improvement over D-CAES, I-CAES, and A-CAES, respectively. The study revealed that achieving power grid independence through the CAES system resulted in annual capital and operating cost savings of 2.22 M$/yr. Adopting the CAES system can significantly reduce CO2 emissions from natural gas combustion to power the grid, resulting in a 29 % decrease in combined emissions from LPG and natural gas. The study's extended findings to similar SONATRACH pumping stations show a reducing CO2 emissions by 22.17 % and savings of 3679 MW/yr. Beyond SONATARCH, the system offers savings and flaring reduction from 100 MW/day and 5.28 bbl/day up to 42400 MW/day and 2329.5 bbl/day.