Thermodynamic and Economic Feasibility of Energy Recovery from Pressure Reduction Stations in Natural Gas Distribution Networks

Abstract

A big amount of the pressure energy content in the natural gas distribution networks is wasted in throttling valves of pressure reduction stations (PRSs). Just a few energy recovery systems are currently installed in PRSs and are mostly composed of radial turboexpanders coupled with cogeneration internal combustion engines or gas-fired heaters providing the necessary preheating. This paper clarifies the reason for the scarce diffusion of energy recovery systems in PRSs and provides guidelines about the most feasible energy recovery technologies. Nine thousand PRSs are monitored and allocated into 12 classes, featuring different expansion ratios and available power. The focus is on PRSs with 1-to-20 expansion ratio and 1-to-500 kW available power. Three kinds of expanders are proposed in combination with different preheating systems based on boilers, heat pumps, or cogeneration engines. The goal is to identify, for each class, the most feasible combination by looking at the minimum payback period and maximum net present value. Results show that small size volumetric expanders with low expansion ratios and coupled with gas-fired heaters have the highest potential for large-scale deployment of energy recovery from PRSs. Moreover, the total recoverable energy using the feasible recovery systems is approximately 15% of the available energy.

A Review of Residual Pressure Utilization of Natural Gas

“…In 2006, Shen et al [37] proposed the use of natural gas pipeline pressure to liquefied natural gas and power generation. Some researchers point out that using turbine expander to recover natural gas pressure energy is one of the most feasible energy recovery technologies [38]. In 2009, London's natural gas distribution network started a project to recycling pressure energy from gas pipelines by turbine expander and combine them with biofuel generators [39].…”

Research of Methods for Improving Energy Efficiency and Emissions Reduction in Distribution Station of Natural Gas Transmission Network

“…Remiantis (Arabkoohsar et al, 2015;Danieli et al, 2020;Farzaneh-Gord et al, 2014;Ghezelbash et al, 2015;Kostowski, 2010;Osiadacz, 2018;Poživil, 2004;Prieskienis, 2015;Rahman, 2010Rahman, , 2011Taheri Seresht et al, 2010;Ipieca, 2013) tyrimų rezultatais, pastebėta, kad DSS yra nepanaudoto energijos atgavimo potencialo, o dujų pašildymas gali būti vykdomas kitais, alternatyviais šaltiniais. Anksčiau cituojamuose tyrimuose buvo nagrinėjamos pavienės arba tik kelios technologijos, jos nebuvo lyginamos tarpusavyje, sprendimai nagrinėjami tik vienu arba dvejais iš trijų (energinio, ekonominio, ekologinio) kriterijų, be to, tyrimai atlikti ne Lietuvos DSS.…”

“…Pagal (Danieli et al, 2020) Dėl šios priežasties ekspanderio veikimo metu dujos atšąla labiau negu naudojant slėgio reguliatorių, todėl jas reikia papildomai pašildyti, kad jų temperatūra išėjime nebūtų žemesnė nei 3 °C. Todėl atliekant skaičiavimus su įrengtu TE, šilumos kiekis, reikalingas dujoms pašildyti, perskaičiuojamas pagal (1) formulę, tačiau Džaulio-Tomsono koeficientą pasirenkant μ = 1,5 o C/bar vietoje slėgio reguliatoriams įprasto μ = 0,6 o C/bar (Prieskienis, 2015).…”

Feasibility study of the energy and economic gain that can be achieved by driving the boiler feedwater pump with a backpressure steam turbine

“…They recommended the usage of turboexpanders to get wasted potential. 20 Demirbas et al studied on steam turbine-based power generation. They concluded that about 33% of thermal energy converted into power by a turbine.…”

“…They recommended the usage of turboexpanders to get wasted potential. 20 Demirbas et al. studied on steam turbine-based power generation.…”