The Thermal Economy of a Circulating Medium and Low Temperature Waste Heat Recovery System of Industrial Flue Gas

Wang, Xutong; Zhang, Meng

doi:10.18280/ijht.390533

Cited by 2 publications

(2 citation statements)

References 18 publications

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“…One stream is compressed in Compressor1 (5-6), and then successively flows into the high-pressure side of the low-temperature recuperator (LTR, 6-7) and the high-temperature recuperator (HTR, 7-8) to be heated. After that, S-CO 2 further absorbs waste heat from the flue gas in Heater1, expanded to carry out work in the high-pressure turbine (HPT, 1-2), and finally cooled by HTR (2-3), LTR (3)(4), and the cooler (4)(5). Another stream of S-CO 2 is first compressed in Compressor2 (5-9), and then heated by the flue gas in Heater2 (9-10).…”

Section: System Layout and Design Parametersmentioning

confidence: 99%

“…To alleviate the dilemma of energy scarcity while reducing the environmental impact of fossil fuels, it is imperative to enhance energy efficiency. The waste heat from industrial waste gas has great recovery potential, and scholars have extensively conducted research on the comprehensive recovery and optimal utilization of industrial waste heat without interfering with the original industrial manufacturing process [3,4]. The organic Rankine cycle (ORC) holds a pivotal position in the realm of low temperature thermal power generation due to the low critical parameters of the organic working fluid [5,6].…”

Section: Introduction 1backgroundmentioning

confidence: 99%

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Research on Off-Design Characteristics and Control of an Innovative S-CO2 Power Cycle Driven by the Flue Gas Waste Heat

Hu,

Liang,

Ding

et al. 2024

Energies

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Recently, supercritical CO2 (S-CO2) has been extensively applied for the recovery of waste heat from flue gas. Although various cycle configurations have been proposed, existing studies predominantly focus on the steady analysis and optimization of different S-CO2 structures under design conditions, and there is a noticeable deficiency in off-design research, especially for the innovative S-CO2 cycles. Thus, in this work aimed at the proposed novel S-CO2 power cycle, off-design characteristics and corresponding control strategies are investigated for the waste heat recovery. Based on the design parameters of the S-CO2 cycle, structural dimensions of printed circuit heat exchangers (PCHEs) and shell-and-tube heat exchangers are determined, and design values of turbines and compressors are specified. On this basis, off-design models for these key components are formulated. By manipulating variables such as cooling water inlet temperature, cooling water mass flow rate, flue gas inlet temperature and flue gas mass flow rate, cycle performances of the system are analyzed under off-design conditions. The simulation results show that when the inlet temperature and the mass flow rate of cooling water vary separately, the thermal efficiency both can reach the maximum value of 28.43% at the design point. For the changes in heat source parameters, the optimum point is slightly deviated from the design condition. Amidst the fluctuations in flue gas inlet temperature, the thermal efficiency optimizes to a peak of 28.56% at 530 °C. In the case of variation in the flue gas mass flow rate, the highest thermal efficiency 28.75% can be obtained. Furthermore, to maintain the efficient and stable operation of the S-CO2 power cycle, the corresponding control strategy of the cooling water mass flow rate is proposed for the cooling water inlet temperature variation. Generally, when the inlet temperature of cooling water increases from 23 °C to 27 °C, the cooling water mass flow should increase from 82.3% to 132.7% of the design value to keep the system running as much as possible at design conditions.

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