For a conventional agricultural tractor the main environmental effects origina ates from the usage phase, more specifically from the diesel use and exhausts. To decre ease the environ nmental effect, it is vital to ...For a conventional agricultural tractor the main environmental effects origina ates from the usage phase, more specifically from the diesel use and exhausts. To decre ease the environ nmental effect, it is vital to find a substitute for fossil diesel as a fuel for agricultural machinery. This s study investig gated the feasib bility of an autonomous battery electric tractor through simulation. The simulated farm is an organic dairy farm of 200 ha with five crops in the crop rotation cycle and a traditional plough among the used implements. Based on the res sult from the simulation cost calculations, sensitivity analysi is and a limited life cycle analysis （LCA） was made. The results show that it is in theory possible to replace a conventional tractor （160 kW） with two autonomous battery powered machines （36 kW engine, 113 kWh battery） with 15% lower costs. Energy consumption would be red duced by 58% a and greenhouse gas emissions by 92% compared to diesel when energy consumption and greenhouse gas emissions from battery manufacturing were included. Today the technology for autonom mous control is under fast development, but there are yet no systems on the market that can handle all machinery tasks like assumed in this study. Challenges yet to solve are , among others, legislative, relevant sensors, logistics and fleet management. Further rese earch is needed to verify the results in practical farming.展开更多
Comparing with continuous production process, unsteady operation process, such as startup and shutdown,tends to abnormal situations due to a large number of operations of operators and dynamic state changes involved. ...Comparing with continuous production process, unsteady operation process, such as startup and shutdown,tends to abnormal situations due to a large number of operations of operators and dynamic state changes involved. To guarantee a safe operation, process hazard analysis(PHA) is very important to proactively identify the potential safety problems. In the chemical process industry, hazard and operability(HAZOP) analysis is the most widely used method. In this paper, based on proposed qualitative simulation and inference method, an automatic HAZOP analysis method for unsteady operation processes is proposed. Mass transfer and relationships among process variables are expressed by Petri net–directed graph model based fuzzy logic. Operating procedure is expressed according to a formal expression. Possible operation deviations from normal operating procedure are identified by using a group of guidewords. Hazards are identified automatically by qualitative simulation and inference when wrong operation process is performed. The method is validated by a rectification column system.展开更多
文摘For a conventional agricultural tractor the main environmental effects origina ates from the usage phase, more specifically from the diesel use and exhausts. To decre ease the environ nmental effect, it is vital to find a substitute for fossil diesel as a fuel for agricultural machinery. This s study investig gated the feasib bility of an autonomous battery electric tractor through simulation. The simulated farm is an organic dairy farm of 200 ha with five crops in the crop rotation cycle and a traditional plough among the used implements. Based on the res sult from the simulation cost calculations, sensitivity analysi is and a limited life cycle analysis （LCA） was made. The results show that it is in theory possible to replace a conventional tractor （160 kW） with two autonomous battery powered machines （36 kW engine, 113 kWh battery） with 15% lower costs. Energy consumption would be red duced by 58% a and greenhouse gas emissions by 92% compared to diesel when energy consumption and greenhouse gas emissions from battery manufacturing were included. Today the technology for autonom mous control is under fast development, but there are yet no systems on the market that can handle all machinery tasks like assumed in this study. Challenges yet to solve are , among others, legislative, relevant sensors, logistics and fleet management. Further rese earch is needed to verify the results in practical farming.
文摘Comparing with continuous production process, unsteady operation process, such as startup and shutdown,tends to abnormal situations due to a large number of operations of operators and dynamic state changes involved. To guarantee a safe operation, process hazard analysis(PHA) is very important to proactively identify the potential safety problems. In the chemical process industry, hazard and operability(HAZOP) analysis is the most widely used method. In this paper, based on proposed qualitative simulation and inference method, an automatic HAZOP analysis method for unsteady operation processes is proposed. Mass transfer and relationships among process variables are expressed by Petri net–directed graph model based fuzzy logic. Operating procedure is expressed according to a formal expression. Possible operation deviations from normal operating procedure are identified by using a group of guidewords. Hazards are identified automatically by qualitative simulation and inference when wrong operation process is performed. The method is validated by a rectification column system.
