Evaluation of the Prospects for Preliminary Cooling of Natural Gas on Main Pipelines Before Compression Through the Discharge of Exhaust Heat of Gas-Turbine Units

Abstract

For the transportation of natural gas through pipelines, gas pumping units (GPU) are installed at numerous compressor stations (CS), the energy carrier for which, in most cases, is transported natural gas. 0.5 ... 1.5 % of the volume of transported gas is consumed (burned) by the pumping unit drive. The situation with the replacement of existing equipment with modern equipment is associated with significant investments, on the one hand, and the uncertainty with the transit of Russian natural gas through gas transmission systems of Ukraine in the near future. More promising is the way to increase the efficiency of the GPU cycle through the use of circuits with preliminary cooling of the compressed gas. The aim of this research is studying the prospects for the application of technology for pre-cooling technological natural gas before compression in a gas pumping unit based on heat-using absorption refrigeration machines. To analyze the effect of pre-cooling of technological natural gas on the compressor stations of main gas pipelines, gas pumping units – GTK-10I were selected. The calculation of GPU power consumption and fuel gas consumption at various temperatures of the process gas at the inlet to the supercharger was performed. The calculation of the operating parameters of the gas pumping unit is performed and the energy and financial prospects of the technology for cooling the process gas before compression in the GPU CS are shown. For the current economic situation (July 2019) in the Ukrainian gas market, the daily decrease in operating costs in standard gas pipelines with a decrease in gas temperature before compression in the gas pumping unit by 20 K ranges from 1800 USD to 3360 USD. A scheme of a recycling plant based on absorption water-ammonia refrigeration machine (AWRM) is proposed, which in the range of initial data allows to reduce the temperature of technological natural gas before compression by 11 ... 13 ° C.

Аналіз Енергетичних Перспектив Охолодження Природного Газу В Магістральних Газопроводах За Допомогою Абсорбційних Холодильних Машин

“…Проведений аналіз шляхів підвищення енергетичної ефективності ГПА [2] показав, що одним з перспективних напрямків, може бути застосування попереднього охолодження газу, що компримується, за допомогою тепловикористальних абсорбційних водоаміачних холодильних машин (АВХМ), які утилізують скидне тепло відпрацьованих продуктів згоряння [3,4].…”

“…Було показано [2], що для поточної економічної ситуації (липень 2019 року) на ринку газу України добове зниження експлуатаційних витрат у типових магістральних газопроводах при зниженні температури газу перед стисненням у ГПА на 20 К становить від 1800 до 3360$.…”

“…Особливий інтерес становлять також занижені температури об'єкта охолодження, які дозволяють підвищити корисний ефект попереднього охолодження природного газу перед стисненням [2]. У стандартних умовах при ρ =0,719 кг/м 3 об'ємна витрата зекономленого паливного газу складе: 79/0,719 = 109,875 м 3 /год.…”

Analysis of energy characteristics of absorption water-ammonia refrigeration machines in the waste heat recovery systems of gas turbine installations on gas main pipelines

“…Of particular interest are also the lowered temperatures of the cooling object, which make it possible to increase the useful effect of pre-cooling natural gas before compression [5].…”

“…An analysis of ways to increase the energy efficiency of gas compressor units [5] shows that one of the pro mising areas could be pre-cooling of the compressed gas using heat-using absorption water-ammonia refrigeration machines (AWRM) that utilize the waste heat of the exhaust products of combustion [6,7]. It is shown [5] that for the current economic situation (July 2019) in the Ukrainian gas market, the daily decrease in operating costs in typical gas pipelines with a decrease in gas temperature before compression by 20 K in gas compressor units ranges from 1800 to 3360 USD. TECHNOLOGY AUDIT AND PRODUCTION RESERVES -№ 5/1(49), 2019…”