| 1. |
- Hu, C., et al.
(författare)
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Different control strategies for MEA based chemical absorption
- 2021
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Ingår i: Energy Proceedings. - : Scanditale AB.
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Konferensbidrag (refereegranskat)abstract
- When capturing CO2 from biomass fired combined heat and power plants, the dynamic changes in the feedstock and the heat and electricity demands can clearly affect the operation of the boiler, which can further affect the performance of chemical absorption CO2 capture. To handle such dynamic changes, control systems are needed. This work aims to compare the performance of two control strategies that can control the reboiler duty in the stripper to achieve a constant capture rate. Control strategy A uses the reboiler temperature as input based on a PID controller; and control strategy B is a modification of control strategy A by introducing a feedforward compensation based on the flowrate of rich solution when regulating the reboiler duty. Based on dynamic simulations, it is found that control strategy B can reduce the settling time and capture more CO2 with a lower average energy penalty within a certain time length.
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| 2. |
- Liu, S., et al.
(författare)
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Improvement of control strategy of CO2 capture from biomass CHP plant by chemical absorption
- 2022
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Ingår i: Clean Coal Technology. - : China International Book Trading Corp. (Guoji Shudian). - 1006-6772. ; 28:9, s. 112-121
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Tidskriftsartikel (refereegranskat)abstract
- When capturing CO2 from biomass fired combined heat and power (CHP) plants, the changes in the feedstock and the heat and electricity demands affect the performance of chemical absorption CO2 capture system. To handle such impact, this paper proposed an improved reboiler duty control strategy (control strategy B) based on the evaluation of the control performance of the traditional feedback control strategy (control strategy A) to achieve a constant capture rate. Control strategy B is based on control strategy A, and introduces feedforward compensation based on rich solution flow rate to form a feedforward plus feedback control strategy. This work aimed to find a control strategy suitable for chemical absorption CO2 capture from biomass CHP, by comparing the control performance, capture system performance and flexible operation performance of both control strategies. Based on the dynamic simulations of CO2 capture from actual biomass fired CHP plant, it is found that compared with the control strategy A, the feedforward compensation of the control strategy B can reduce the response time of the reboiler duty to external disturbances, and improve the timeliness and accuracy of the regulation of reboiler duty. The settling time of capture rate is reduced by 54 mins with the control strategy B. Facing the flexible change of capture rate setpoint, the time required for the stabilization of capture rate is reduced by 57.9% with control strategy B. Under the continuous external disturbance, the capture rate is maintained at ±3% of the setpoint with control strategy B. At the same time, the energy penalty is reduced by 0.14%, and the total captured CO2 is increased by 0.35%. In addition, the results of dynamic simulation and traditional steady-state simulation show that the dynamic simulation can reflect the impact of external disturbances on the capture system more accurately, and provide a reference for the integration and optimization of related processes.
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| 3. |
- Wang, S., et al.
(författare)
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A Method to Assess the CO2 Capture Potential from a Biomass-fired CHP
- 2021
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Ingår i: Energy Proceedings. - : Scanditale AB.
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Konferensbidrag (refereegranskat)abstract
- The bioenergy with CO2 capture and storage (BECCS) is an important solution to reduce CO2 emissions. This paper proposed a new method that can accurately access CO2 capture potential from a biomass-fired combined heat and power (BCHP). Chemical absorption is used as CO2 capture technology. By carefully considering the temperatures of the heat required by district heating and CO2 capture, the allocation of the available heat from flue gas condensation and extracted steam condensation for different purposes has been optimized. By using a real BCHP with a thermal capacity of 200MW as a case study, results show that the captured CO2 was 23.42t/day without any change in heat and power supply, which was 1.77% of the total released CO2.
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| 4. |
- Zheng, Wandong, et al.
(författare)
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COVID-19 Impact on Operation and Energy Consumption of Heating, Ventilation and Air-Conditioning (HVAC) Systems
- 2021
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Ingår i: Advances in Applied Energy. - : Elsevier BV. - 2666-7924. ; 3, s. 100040-100040
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Tidskriftsartikel (refereegranskat)abstract
- Heating, ventilation and air-conditioning (HVAC) system is favourable for regulating indoor temperature, relative humidity, airflow pattern and air quality. However, HVAC systems may turn out to be the culprit of microbial contamination in enclosed spaces and deteriorate the environment due to inappropriate design and operation. In the context of COVID-19, significant transformations and new requirements are occurring in HVAC systems. Recently, several updated operational guidelines for HVAC systems have been issued by various institutions to control the airborne transmission and mitigate infection risks in enclosed environments. Challenges and innovations emerge in response to operational variations of HVAC systems. To efficiently prevent the spread of the pandemic and reduce infection risks, it is essential to have an overall understanding of impacts caused by COVID-19 on HVAC systems. Therefore, the objectives of this article are to: (a) provide a comprehensive review of the airborne transmission characteristics of SARS-CoV-2 in enclosed spaces and a theoretical basis for HVAC operation guideline revision; (b) investigate HVAC-related guidelines to clarify the operational variations of HVAC systems during the pandemic; (c) analyse how operational variations of HVAC systems affect energy consumption; and (d) identify the innovations and research trends concerning future HVAC systems. Furthermore, this paper compares the energy consumption of HVAC system operation during the normal times versus pandemic period, based on a case study in China, providing a reference for other countries around the world. Results of this paper offer comprehensive insights into how to keep indoor environments safe while maintaining energy-efficient operation of HVAC systems.
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