Model prediction of the operating behavior of a circulating fluidized bed boiler

An improved mathematical model for a circulating fluidized bed (CFB) boiler based on the model developed earlier by the authors was applied to simulate the operation of a 12 MW CFB boiler. The influences of the excess air ratio, primary air ratio, coal particle size distribution, coal properties (ash content and volatile content) and Ca/S ratio on the boiler operation were analyzed. The results showed that the model simulation may be applied to the optimum design and economic operation of the CFB boiler.

800-MW Supercritical Coal-Fired Boilers in Suizhong Power Plant

This article reviews the problems of Russia-made 800-MW coal-fired supercritical boilers in Suizhong Power Plant, such as burner bumout, water-wall leakage, slag screenⅠexplosion, crack happened on the desuperheater outlet of reheater and welding defect of economizer; tells the process of renovating these units by modifying the original design and adjusting the operation parameters. After several years' effort, all the problems have been well solved. The experience may be useful for other imported units in China.

The Secrets in the Steam

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.