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Irriyanto, Miqdar Zulfikar,Lim, Hyung-Soo,Choi, Bum-Seog,Myint, Aye Aye,Kim, Jaehoon Elsevier science 2019 The Journal of supercritical fluids Vol.154 No.-
<P><B>Abstract</B></P> <P>The supercritical organic Rankine cycle (SORC) is a highly promising technique to recover non-utilized low-to-medium-temperature heat sources. A good thermal stability of the working fluid is crucial to create a safe SORC system. Herein, the thermal stability of a new type of working fluid, HFO-1234ze(E) (<I>trans</I>-1,3,3,3-tetrafluoroprop-1-ene), which is an environmentally friendly fourth-generation refrigerant, is investigated in supercritical regimes. The experimental conditions are designed for long-term reactions for 56 days at 453.15 K and 5 MPa, which represent the highest temperature and pressure, respectively, at the SORC turbine inlet. In addition, the effects of temperature, pressure, and time on the decomposition of HFO-1234ze(E) are investigated over a short experimental period of up to 24 h to propose the reaction kinetics. Decomposed gases species from HFO-1234ze(E) included difluoromethane (HFC-32), pentafluoro ethane (HFC-125), 1,1,1-trifluoroethane (HFC-143a), 1,1,1,2,2-pentafluoropropane (HFC-245fa). For extended time periods or in high-pressure and high-temperature conditions, HFO-1234ze(E) decomposes to form liquid products with weight average molecular weights in the range of 470–740 g mol<SUP>–1</SUP>. The decomposition of HFO-1234ze(E) can be fitted with a first-order kinetic model. Under the assumption that major decomposition occurs at the turbine inlet, the decomposition rate of HFO-1234ze(E) is found to be 0.02% per year in this study.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Thermal stability of HFO-1234ze(E) was investigated in the conditions of SORC. </LI> <LI> Both temperature and pressure played a role in decomposing HFO-1234ze(E). </LI> <LI> The decomposition of HFO-1234ze(E) was fitted with a first-order kinetic model. </LI> <LI> The decomposition rate of HFO-1234ze(E) at the turbine inlet was 0.02% per year. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Miqdar Zulfikar Irriyanto,Hyung-Soo Lim,Bum-SeogChoi,Minsang Lee,Aye Aye Myint,Jaehoon Kim 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.90 No.-
The supercritical organic Rankine cycle (SORC) is considered as a potential technique for converting heatwaste resources to electricity. Owing to its low global warming potential, HFO-1234ze(E) (trans-1,3,3,3-tetrafluoroprop-1-ene) is a suitable workingfluid for the SORC system. This paper proposes a simplekinetic method for evaluating the thermal decomposition of HFO-1234ze(E) based on the temperaturesand pressures in the SORC loop. A long-term decomposition test conducted at temperatures of 433.15–473.15 K under a pressure of 5.0 MPa was used to establish a kinetic equation based on thefirst-orderkinetic model. At 423.15 K, in the high-temperature region of the SORC loop, the decomposition rate ofHFO-1234ze(E) was only 1.25% for the 50-year continuous running cycle. When the temperature of thehigh-temperature region increased by 20 K and 40 K, decompositions of HFO-1234ze(E) significantlyincreased to 5.24% and 18.40%, respectively, which highlights the high sensitivity of the thermaldecomposition rate toward the temperature in the SORC loop.
Miqdar Zulfikar Irriyanto,Hyung-Soo Lim,최범석,Aye Aye Myint,김재훈 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.96 No.-
Supercritical organic Rankine cycle (SORC) is considered one of the most promising candidates forproducing electricity from medium- to low-temperature heat resources. Various types of alloys areconsidered potential materials for constructing the main SORC components. The decomposition of aworkingfluid, R-1234ze(E) (trans-1,3,3,3-tetrafluoropropane), in the high-temperature region of theSORC loop produces hydrogenfluoride (HF), which affects the stability of the alloys. In this work, thecorrosion behavior of seven selected materials under supercritical R-1234ze(E) conditions was examined. In the turbine inlet region of the designed SORC loop (180 C, 5 MPa), the formation of a thick scale layer(10–40 nm) and penetration of F in the subsurface region were observed in the SS304 and SS316 samplesafter seven days of exposure. In the case of copper and bronze, the erosion of the surface and holeformation at the bulk phase were caused by the deep penetration of HF. In contrast, SS630 and Inconel718 exhibited excellent corrosion stability without changing the chemical environment of theirsubsurface regions. In the case of Al6061, preferential segregation of the MgF2 layer in the subsurfaceregion was observed.