Power reduction in air separation units for oxy-combustion processes based on exergy analysis

Author(s):  
Chao Fu ◽  
Truls Gundersen
1998 ◽  
Vol 39 (16-18) ◽  
pp. 1821-1826 ◽  
Author(s):  
R.L. Cornelissen ◽  
G.G. Hirs

2016 ◽  
Author(s):  
S. Tesch ◽  
T. Morosuk ◽  
G. Tsatsaronis

The increasing demand for primary energy leads to a growing market of natural gas and the associated market for liquefied natural gas (LNG) increases, too. The liquefaction of natural gas is an energy- and cost-intensive process. After exploration, natural gas, is pretreated and cooled to the liquefaction temperature of around −160°C. In this paper, a novel concept for the integration of the liquefaction of natural gas into an air separation process is introduced. The system is evaluated from the energetic and exergetic points of view. Additionally, an advanced exergy analysis is conducted. The analysis of the concepts shows the effect of important parameters regarding the maximum amount of liquefiable of natural gas and the total power consumption. Comparing the different cases, the amount of LNG production could be increased by two thirds, while the power consumption is doubled. The results of the exergy analysis show, that the introduction of the liquefaction of natural gas has a positive effect on the exergetic efficiency of a convetional air separation unit, which increases from 38% to 49%.


2021 ◽  
Vol 1 (1) ◽  
pp. 006-015
Author(s):  
E. H. Betelmal ◽  
A. M. Naas ◽  
A. Mjani

In this paper, we investigated a thermodynamic model of the regeneration gas turbine cycle with nitrogen supplied during the compression process. A suitable quantity of nitrogen that comes from the air separation cycle (Linde cycle) is injected between the stages of the compressor where it is evaporated, then the nitrogen and air mixture enters into the combustion chamber where it is burned and expanded in the turbine. We used this method to reduce greenhouse gases and improve gas turbine efficiency. In this work, we evaluated the operational data of the regeneration gas turbine cycle and the maximum amount of nitrogen that can be injected into the compressor. We also investigated the performance variation due to nitrogen spray into the compressor, and the effect of varying ambient temperature on the performance of gas turbines (thermal efficiency, power), as well as a comparison between the normal gas turbine cycle, and the remodelled compression cycle. The exergy analysis shows that the injection of the nitrogen will increase exergy destruction. The results demonstrated an 8% increase in the efficiency of the cycle, furthermore, CO2 emission decreased by 11% when the nitrogen was injected into the compressor.


2000 ◽  
Author(s):  
Zelong Liu ◽  
Hongguang Jin ◽  
Rumou Lin

Abstract Integrated Gasification Combined Cycle (IGCC) is considered as one of the advanced clean coal power technologies. Here, we have investigated an IGCC with air separation unit (ASU) on the basis of exergy analysis, and clarified the distribution of exergy destruction in sub-systems including air separation unit, coal gasifier, coal gas clean-up unit, air compressor, combustor of gas turbine, gas turbine, heat recovery steam generation and steam turbine. Particularly, we have focused on the interaction between the ASU and the gas turbine (GT). The results obtained disclosed the significant role of the integration between air separation unit and air compressor in the GT, and the effect of nitrogen injection to the combustor on IGCC overall performance. The study also points out that larger exergy destruction take place in the processes of gasification, combustion in GT, and air separation, and so does the change of exergy destruction distribution with the air integration degree and the nitrogen injection ratio. We have demonstrated the potential for improving the IGCC system. This investigation will be valuable for the synthesis of next-generation IGCC.


2013 ◽  
Vol 17 (1) ◽  
pp. 121-136 ◽  
Author(s):  
Yas A. Alsultannty ◽  
Nayef Al-Shammari

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