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

• Main Authors: Alexander Titlov, Oleg Vasyliv, Alnamer Abdelkader, Alexey Morozov
• Format: Article
• Language: English
• Published: PC Technology Center 2019-10-01
• Series: Tehnologìčnij Audit ta Rezervi Virobnictva
• Subjects: water-ammonia absorption chillers; waste heat; energy efficiency; natural gas pre-cooling; main gas pipelines
• Online Access: http://journals.uran.ua/tarp/article/view/183853
• ISSN: 2226-3780; 2312-8372

One of the promising ways to reduce operating losses in main gas pipelines is pre-cooling of compressed gas using heat-using absorption water-ammonia refrigeration machines (AWRM), which utilize the waste heat of the exhaust products of the combustion of gas pumping units. The object of research is the energy characteristics of the AWRM in a wide range of operating parameters (outdoor temperatures), which are currently not studied. A methodology for modeling AWRM modes is developed, analytical studies are conducted and the results are obtained in a wide range of outdoor temperatures. The study is conducted using theoretical analysis of AWRM cycles in a wide range of outdoor temperatures and temperatures of the cooling object. The analysis of the calculation results showed that in the range of design parameters there is a maximum energy efficiency AWRM. The most obvious is the presence of a maximum for operating conditions at cooling medium temperatures of 20…32 °С and low temperatures of the cooling object (minus 25 °С). As the temperature of the cooling object decreases, the maximum energy efficiency shifts to the region of high temperatures of the heating medium, and its numerical values decrease. At heating source temperatures from 90 °С to 130 °С, the electric power of the circulation pump has a maximum value. Subsequently, with an increase in the temperature of the heating source, its asymptotic decrease and slow decrease are observed. In this case, the greatest changes occur at elevated temperatures of the cooling medium (32 °С). The simulation results allow to determine the most energy-efficient operating modes of the AWRM with various sources of thermal energy (temperatures from 90 to 160 °С) and to develop cooling systems for a wide temperature range (minus 30…15 °С). To achieve such optimal conditions, an appropriate combination of the composition of the working fluid and the temperature of the heating source is necessary.