Since the combustion system of coal-fired boiler in thermal power plant is characterized as time varying, strongly coupled, and nonlinear, it is hard to achieve a satisfactory performance by the conventional proportio...Since the combustion system of coal-fired boiler in thermal power plant is characterized as time varying, strongly coupled, and nonlinear, it is hard to achieve a satisfactory performance by the conventional proportional integral derivative (PID) control scheme. For the characteristics of the main steam pressure in coal-fired power plant boiler, the sliding mode control system with Smith predictive structure is proposed to look for performance and robustness improvement. First, internal model control (IMC) and Smith predictor (SP) is used to deal with the time delay, and sliding mode controller (SMCr) is designed to overcome the model mismatch. Simulation results show the effectiveness of the proposed controller compared with conventional ones.展开更多
The slagging/fouling due to the accession of fireside deposits on the steam boilers decreases boiler efficiency and availability which leads to unexpected shut-downs. Since it is inevitably associated with the three m...The slagging/fouling due to the accession of fireside deposits on the steam boilers decreases boiler efficiency and availability which leads to unexpected shut-downs. Since it is inevitably associated with the three major factors namely the fuel characteristics, boiler operating conditions and ash behavior, this serious slagging/fouling may be reduced by varying the above three factors. The research develops a generic slagging/fouling prediction tool based on hybrid fuzzy clustering and Artificial Neural Networks (FCANN). The FCANN model presents a good accuracy of 99.85% which makes this model fast in response and easy to be updated with lesser time when compared to single ANN. The comparison between predictions and observations is found to be satisfactory with less input parameters. This should be capable of giving relatively quick responses while being easily implemented for various furnace types.展开更多
Numerical simulation of complex systems and components by computers is a fundamental phase of any modern engineering activity. The traditional methods of simulation typically entail long, iterative processes which lea...Numerical simulation of complex systems and components by computers is a fundamental phase of any modern engineering activity. The traditional methods of simulation typically entail long, iterative processes which lead to large simulation times, often exceeding transient real time. Artificial neural networks （ANNs） may be advantageous in this context, the main advantage being the speed of computation, the capability of generalizing from the few examples, robustness to noisy and partially incomplete data and the capability of performing empirical input-output mapping without complete knowledge of underlying physics. In this paper, the simulation of steam generator is considered as an example to show the potentialities of this tool. The data required for training and testing the ANN is taken from the steam generator at Abott Power Plant, Champaign （USA）. The total number of samples is 9600 which are taken at a sampling time of three seconds. The performance of boiler （drum pressure, steam flow rate） has been verified and tested using ANN, under the changes in fuel flow rate, air flow rate and load disturbance. Using ANN, input-output mapping is done and it is observed that ANN allows a good reproduction of non-linear behaviors of inputs and outputs.展开更多
The sugar cane containing minimum 30% fiber was referred as bagasse and used the generation of power required for the operation of sugar mill. The bagasse is fired in the boiler for producing steam at high pressure, w...The sugar cane containing minimum 30% fiber was referred as bagasse and used the generation of power required for the operation of sugar mill. The bagasse is fired in the boiler for producing steam at high pressure, which is extracted through various single high capacity turbines and used in the process. The installation of high pressure boilers and high pressure turbo-generators has provision for the operation of co-generation plant during the off-season also that enhances the power generation from 9MW to 23MW. The annual monetary benefits achieved are Rs. 204.13 million and this was based on cost of power sold to the grid @ Rs 2.548 per unit, sugar season of 219 days and off season of 52 days. This required an investment of Rs 820.6 million. The investment had an attractive simple payback period of 48 months.展开更多
Introduction： There are several components in motion before steam reaches its destination. Each element plays a significant role in generating adequate steam for terminal sterilization of critical devices. The knowl...Introduction： There are several components in motion before steam reaches its destination. Each element plays a significant role in generating adequate steam for terminal sterilization of critical devices. The knowledge and awareness of factors that contribute to wet packs will assist in maximizing steam quality. Steam sterilization of critical devices such as surgical instruments in the acute care setting is fundamentally necessary to prevent infection. Sterile packaging that is wet after removal from the autoclave is considered contaminated. This wet pack presents a significant infection risk and indicates a defect in the sterilization process. The identification of wet packs prompted the exploration of the sterilization process. In reviewing the evolution of steam production, our investigation began in the boiler room. The assessments of the boiler operations, steam quality, and loading technique of the autoclaves were examined as possible contributing factors in the propagation of wet packs. Methods： The investigation was performed in a 592-bed non-teaching acute care facility in New Jersey. Methods to ensure the integrity of steam included; a cut point of 〈 3,500 ppm TDSs （total dissolved solids）, （daily） calibration of the TDS analyzer to ensure accurate TDS measurement, increase in autoclave drying times, reduction of the weight density of surgical trays from 25 lbs. to 20 lbs., and revision of sterilization loading practices. Modifications were implemented from June 2015 to December 2015. Results： No wet packs were identified from January through May 2016. In June 2016, 2 wet packs were detected, and upon further analysis there was an increase in the water level of the boiler drum. After this special cause variation, no wet packs have been identified. Conclusion： The monitoring and documentation of boiler room parameters and CSP （central sterile processing） practice modifications may have impacted the reduction of wet pack.展开更多
基金Supported by the National Natural Science Foundation of China (61174059, 60934007, 61233004)the National Basic Research Program of China (2013CB035406)Shanghai Rising-Star Tracking Program (11QH1401300)
文摘Since the combustion system of coal-fired boiler in thermal power plant is characterized as time varying, strongly coupled, and nonlinear, it is hard to achieve a satisfactory performance by the conventional proportional integral derivative (PID) control scheme. For the characteristics of the main steam pressure in coal-fired power plant boiler, the sliding mode control system with Smith predictive structure is proposed to look for performance and robustness improvement. First, internal model control (IMC) and Smith predictor (SP) is used to deal with the time delay, and sliding mode controller (SMCr) is designed to overcome the model mismatch. Simulation results show the effectiveness of the proposed controller compared with conventional ones.
文摘The slagging/fouling due to the accession of fireside deposits on the steam boilers decreases boiler efficiency and availability which leads to unexpected shut-downs. Since it is inevitably associated with the three major factors namely the fuel characteristics, boiler operating conditions and ash behavior, this serious slagging/fouling may be reduced by varying the above three factors. The research develops a generic slagging/fouling prediction tool based on hybrid fuzzy clustering and Artificial Neural Networks (FCANN). The FCANN model presents a good accuracy of 99.85% which makes this model fast in response and easy to be updated with lesser time when compared to single ANN. The comparison between predictions and observations is found to be satisfactory with less input parameters. This should be capable of giving relatively quick responses while being easily implemented for various furnace types.
文摘Numerical simulation of complex systems and components by computers is a fundamental phase of any modern engineering activity. The traditional methods of simulation typically entail long, iterative processes which lead to large simulation times, often exceeding transient real time. Artificial neural networks （ANNs） may be advantageous in this context, the main advantage being the speed of computation, the capability of generalizing from the few examples, robustness to noisy and partially incomplete data and the capability of performing empirical input-output mapping without complete knowledge of underlying physics. In this paper, the simulation of steam generator is considered as an example to show the potentialities of this tool. The data required for training and testing the ANN is taken from the steam generator at Abott Power Plant, Champaign （USA）. The total number of samples is 9600 which are taken at a sampling time of three seconds. The performance of boiler （drum pressure, steam flow rate） has been verified and tested using ANN, under the changes in fuel flow rate, air flow rate and load disturbance. Using ANN, input-output mapping is done and it is observed that ANN allows a good reproduction of non-linear behaviors of inputs and outputs.
文摘The sugar cane containing minimum 30% fiber was referred as bagasse and used the generation of power required for the operation of sugar mill. The bagasse is fired in the boiler for producing steam at high pressure, which is extracted through various single high capacity turbines and used in the process. The installation of high pressure boilers and high pressure turbo-generators has provision for the operation of co-generation plant during the off-season also that enhances the power generation from 9MW to 23MW. The annual monetary benefits achieved are Rs. 204.13 million and this was based on cost of power sold to the grid @ Rs 2.548 per unit, sugar season of 219 days and off season of 52 days. This required an investment of Rs 820.6 million. The investment had an attractive simple payback period of 48 months.
文摘Introduction： There are several components in motion before steam reaches its destination. Each element plays a significant role in generating adequate steam for terminal sterilization of critical devices. The knowledge and awareness of factors that contribute to wet packs will assist in maximizing steam quality. Steam sterilization of critical devices such as surgical instruments in the acute care setting is fundamentally necessary to prevent infection. Sterile packaging that is wet after removal from the autoclave is considered contaminated. This wet pack presents a significant infection risk and indicates a defect in the sterilization process. The identification of wet packs prompted the exploration of the sterilization process. In reviewing the evolution of steam production, our investigation began in the boiler room. The assessments of the boiler operations, steam quality, and loading technique of the autoclaves were examined as possible contributing factors in the propagation of wet packs. Methods： The investigation was performed in a 592-bed non-teaching acute care facility in New Jersey. Methods to ensure the integrity of steam included; a cut point of 〈 3,500 ppm TDSs （total dissolved solids）, （daily） calibration of the TDS analyzer to ensure accurate TDS measurement, increase in autoclave drying times, reduction of the weight density of surgical trays from 25 lbs. to 20 lbs., and revision of sterilization loading practices. Modifications were implemented from June 2015 to December 2015. Results： No wet packs were identified from January through May 2016. In June 2016, 2 wet packs were detected, and upon further analysis there was an increase in the water level of the boiler drum. After this special cause variation, no wet packs have been identified. Conclusion： The monitoring and documentation of boiler room parameters and CSP （central sterile processing） practice modifications may have impacted the reduction of wet pack.
