Starting the cracking gas compressor and precooling the refrigeration system are keys to start-up of an ethylene plant and accounts for up to 50% of the total start-up time and plant flare emissions. Premature feeding...Starting the cracking gas compressor and precooling the refrigeration system are keys to start-up of an ethylene plant and accounts for up to 50% of the total start-up time and plant flare emissions. Premature feeding of cracking furnaces can be avoided if the cracking gas compressor is started and the refrigeration system is precooled in advance using mixed gas as the start-up working medium(SWM). Start-up scenario with mixed gas as SWM could significantly reduce the emission loss and shorten the precooling time. Research shows that making appropriate start-up scheme is important not only to ensure operational safety and feasibility, but also to reduce energy consumption. In this paper, a method is proposed to select suitable start-up operational parameters of compression and refrigeration system with sufficient safe operating ranges and short precooling time. The complex interrelation among key parameters of start-up is analyzed. It is found that higher energy consumption, especially for super high-pressure steam(SS), can promote operational safety and shorten the precooling time during start-up.Based on steady-state and dynamic simulation, appropriate operating parameter ranges are determined with reasonable SS consumption. A real case study demonstrates that an appropriate start-up scheme will optimize the operation.展开更多
This article studies the wall temperature distribution of inorganic heat transfer element in different working conditions by experiments, and analyzes the impact of inclination angle, heating power, different kinds of...This article studies the wall temperature distribution of inorganic heat transfer element in different working conditions by experiments, and analyzes the impact of inclination angle, heating power, different kinds of cooling medium and different inlet temperature of cooling medium on the starting property of inorganic heat transfer element.展开更多
中压设备是列车上较大功率的设备,这些设备分散在列车各系统中,由辅助供电系统集中为其供电。由于电感效应,中压设备启动时的峰值电流会对辅助供电系统的安全性和稳定性产生不利影响。为保证列车辅助供电系统稳定、可靠运行,需要有效地...中压设备是列车上较大功率的设备,这些设备分散在列车各系统中,由辅助供电系统集中为其供电。由于电感效应,中压设备启动时的峰值电流会对辅助供电系统的安全性和稳定性产生不利影响。为保证列车辅助供电系统稳定、可靠运行,需要有效地控制中压设备启动时的峰值电流。基于列车控制与管理系统(TCMS,Train Control and Management System)的控制逻辑,研究列车上电自检阶段中压设备错时顺序启动控制方法,列车运行中空调压缩机错时启动控制方法,以及辅助供电系统故障工况下中压设备减载启动控制方法,避免中压负载峰值电流叠加对辅助供电系统造成的不良影响,确保在故障情况下有足够的辅助供电能力。通过实验室仿真测试和运营线上实车试验,初步验证了在辅助供电备用率和启动峰值电流的限制约束下,列车中压设备启动控制方法的有效性。展开更多
基金Supported by the National Basic Research Program of China(2012CB720500)the National Natural Science Foundation of China(U1462206)
文摘Starting the cracking gas compressor and precooling the refrigeration system are keys to start-up of an ethylene plant and accounts for up to 50% of the total start-up time and plant flare emissions. Premature feeding of cracking furnaces can be avoided if the cracking gas compressor is started and the refrigeration system is precooled in advance using mixed gas as the start-up working medium(SWM). Start-up scenario with mixed gas as SWM could significantly reduce the emission loss and shorten the precooling time. Research shows that making appropriate start-up scheme is important not only to ensure operational safety and feasibility, but also to reduce energy consumption. In this paper, a method is proposed to select suitable start-up operational parameters of compression and refrigeration system with sufficient safe operating ranges and short precooling time. The complex interrelation among key parameters of start-up is analyzed. It is found that higher energy consumption, especially for super high-pressure steam(SS), can promote operational safety and shorten the precooling time during start-up.Based on steady-state and dynamic simulation, appropriate operating parameter ranges are determined with reasonable SS consumption. A real case study demonstrates that an appropriate start-up scheme will optimize the operation.
文摘This article studies the wall temperature distribution of inorganic heat transfer element in different working conditions by experiments, and analyzes the impact of inclination angle, heating power, different kinds of cooling medium and different inlet temperature of cooling medium on the starting property of inorganic heat transfer element.
文摘中压设备是列车上较大功率的设备,这些设备分散在列车各系统中,由辅助供电系统集中为其供电。由于电感效应,中压设备启动时的峰值电流会对辅助供电系统的安全性和稳定性产生不利影响。为保证列车辅助供电系统稳定、可靠运行,需要有效地控制中压设备启动时的峰值电流。基于列车控制与管理系统(TCMS,Train Control and Management System)的控制逻辑,研究列车上电自检阶段中压设备错时顺序启动控制方法,列车运行中空调压缩机错时启动控制方法,以及辅助供电系统故障工况下中压设备减载启动控制方法,避免中压负载峰值电流叠加对辅助供电系统造成的不良影响,确保在故障情况下有足够的辅助供电能力。通过实验室仿真测试和运营线上实车试验,初步验证了在辅助供电备用率和启动峰值电流的限制约束下,列车中压设备启动控制方法的有效性。
