Naoyuki Nagafuchi

Smart Design System for Coal-Fired Boiler Buildings in Thermal Power Plants

To meet expanding energy requirements, supercritical sliding pressure operation has become a major trend in recent thermal power plants. The technology for this operation was developed as high efficient thermal power plants with lower emission. We have continued to develop supercritical steam plant with sliding pressure operation to meet the demand for high efficiency coal-fired power plants that has arisen due to circumstances such as high fuel prices, exacting plant site requirements, and very strict environmental requirements. Because of our accumulated expertise and practical experience, we have received orders for several coal-fired engineering, procurement, and construction (EPC) projects. We have developed a smart design system for a coal-fired boiler building using an information technology (IT) tool for a large-scale and complex system design. We call this design system the Flexible Engineering System. This system is composed of three support functions: boiler general arrangement, boiler building layout, and bill of quantity estimation. First, the boiler general arrangement support function enables us to automatically create basic engineering specifications based on the required specifications. This system generates the basic engineering required using parametric engineering practice with parameterization of several required specifications. Second, the support function of the boiler building layout planning enables us to make 3-D models of the boiler building automatically. The 3-D models of the boiler, coal silos, and air and gas ducts are generated from the boiler general arrangement. The 3-D models of the steel structures are generated from loading data. The steel structure and brace models can even reflect the results of stress analysis. The 3-D models of large components, for example, the pulverizer, forced draft fan, etc., are arranged by selecting a matching model from the data library. The 3-D piping models are generated along the optimum path routing using a search method that combines dynamic programming with a layout rule-base. The 3-D floor and head-clearance model, which means a walk space and a maintenance space, are generated taking into consideration layout rules such as those concerning installation and maintenance. This support system can check for interference between the steel structures and each component. Third, the support function of the bill of quantity estimation makes it possible to estimate the quantity of materials from the specification data and configuration data of the 3-D models. The developed system is now under operation. The results indicate that it provides high engineering accuracy and reliability.Copyright

Estimation of the Operating Characteristics of the Adjustable Speed Gas Turbine Power Generation System During Partial Load Operation

This paper proposes an application of the simple cycle adjustable speed gas turbine power generation system for use as an independent power producer combined with a heavy duty gas turbine (output power 25MW, turbine inlet temperature 1400K class) having adjustable speed generators. Comparison results for a method to improve the thermal efficiency of this system using low NOx combustors are obtained.The results of a performance study of the static characteristics for the system using forced IGV (Inlet Guide Vane) opening control during partial load adjustable speed operation, show an effect on thermal efficiency improvement. Comparison of the dynamic characteristics for the system using existing controllers and the system using the proposed controllers shows, the latter is able to restrain fluctuation of the fuel to air mass ratio during a transient changing the target rotational speed, under restricted operating conditions.Copyright