Modern Reaction HP/IP Turbine Technology Advances and Experiences

Modern steam turbines of the author’s company are based on advanced technology such as high efficiency seals, 3D blading, single inner cylinders, and advanced materials. These technologies result in a compact opposed-flow HP/IP combined cylinder design with high long-term efficiency, reliability, and availability. This paper will illustrate the features, benefits, and operational experience of large steam turbines with advanced technologies using an opposed-flow HP/IP cylinder. The paper will also address the relative performance of this type of steam turbine against its predecessors. Specific examples will be examined: 350 MW fossil units in the Asian market, a typical 250 MW combined cycle steam turbine in the American market, a 700 MW three-cylinder class design for conventional steam plants developed for the global coal market, and a 600 MW steam turbine upgrade.

A Design Model of a New Positive Displacement Rotary Compressor Based on Trochoidal Geometry for High Pressure Applications

The desire to achieve high discharge pressures at low manufacturing and maintenance costs has resulted in the development of a number of new positive displacement rotary compressor designs. The proposed design involves a compressor with a trochoidal casing geometry and a rotor orbiting the casing interior. This arrangement generates a varying trapped volume between the rotor and the casing thus providing the necessary compression for the compressor. The major advantage of this design is its inherent simple two-dimensional configuration which makes it a very cheap device to manufacture. Furthermore, the oil-flooded lubrication system used with this design not only acts as a lubricant but also as a coolant to the main gas flow and consequently improves the mechanical reliability of the compressor. This paper presents a complete design model developed to investigate the performance of the compressor. The geometrical, kinematic, and dynamic equations of the casing and rotor are derived. A model of the compressor thermodynamic cycle and gasdynamic performance is presented. A comparison between the developed model and the experimental results of a prototype compressor testing is presented. The comparison shows that the developed model indeed captures the compressor performance trends with considerable accuracy at the design conditions. Deviation between the model and experimental results at the off design conditions is due to inaccuracies in the inlet and exit port loss models at the off design conditions.

New Concept of a Micro Gas Turbine Based Co-Generation Package for Performance Improvement in Practical Use

As the energy consumption has been increasing rapidly in the commercial sector in Japan, the market potential for the micro gas turbine is significant and it will be realized substantially if the thermal efficiency is improved. One of measures is to introduce the steam injection system using the steam generated by the heat recovery steam generator. Steam injection tests have been carried out using a micro gas turbine (Capstone C60). Test results showed that key performance parameters such as power output, thermal efficiency and emissions were improved by the steam injection. The stable operation of micro gas turbine with steam injection was confirmed under various operating conditions. Consequently, a micro gas turbine based co-generation package with steam injection driven by a heat recovery steam generator (HRSG) with supplementary firing is proposed.

Guidance on Conducting Tests of Inlet Chiller Systems Installed in GT Inlets

This paper provides comprehensive methodology on testing inlet chiller systems that are used for Gas Turbine Inlet Air Conditioning. It will serve as a guiding document for the Inlet Chiller Project Team formed by PTC 51, “Combustion Turbine Inlet Air Conditioning Equipment” for use in scripting that code’s section on Inlet Chiller Performance Testing. This paper shows the conceptual similarities that can be drawn between inlet chiller and overall plant performance testing, as well as detailing the pertinent test scopes and boundaries, identifying expected test objectives, and listing the applicable test boundary parameters to be used for correction. Addressing an industry need, this paper also offers guidance on testing these components / systems at conditions different than design. Current equipment code committees, such as ASME PTC 22 on Gas Turbines, and ASME PTC 46 on Overall Plant Performance Testing, have concluded that inlet air conditioning equipment must be out of service while testing the major plant equipment. This would require the inlet chilling system to be tested separately. This requirement dictates that a technically-sound method of inlet chiller testing be codified in a timely manner.

Probabilistic Performance Analysis of Eroded Compressor Blades

This paper presents a probabilistic analysis of the effect of erosion on the performance of compressor fan blades. A realistic parametric CAD model is developed to represent eroded blades. Design of Experiments (DOE) techniques are employed to generate a set of candidate points, which are combined with a parametric geometry modeling and grid generation routine to produce a hybrid mesh. A multigrid Reynolds-Averaged Navier Stokes (RANS) solver HYDRA with Spalart Allmaras turbulence model is used for Computational Fluid Dynamics (CFD) simulations. The data generated is used to create a surrogate model for efficient uncertainty propagation. This method is applied to a typical Rolls Royce compressor fan blade section. Monte Carlo Simulation, using the surrogate model, is executed for the probabilistic analysis of the compressor fan blade. Results show upto 5% increase in pressure loss for the eroded compressor fan blades.

Development of a Dual-Fuel Gas Turbine Engine of Liquid and Low-Calorific Gas

We developed a dual-fuel single can combustor for the Niigata Gas Turbine (NGT2BC), which was developed as a continuous-duty gas turbine capable of burning both kerosene and digester gas. The output of the NGT2BC is 920 kW for continuous use with digester gas and 1375 kW for emergency use with liquid fuel. Digester gas, obtained from sludge processing at sewage treatment plants, is a biomass energy resource whose use reduces CO2 emissions and take advantage of an otherwise wasted energy source. Design features for good combustion with digester gas include optimized the good matching of gas injection and swirl air and reduced reference velocity. The optimal combination of these parameters was determined through CFD analysis and atmospheric rig testing.

Research on Optimization Model for Power Coal Blending Based on Genetic Algorithm

The slagging process is a popular problem in coal-fired power plants because the coal properties deviate from designed condition, at the same time, power plants is enduring a great pressure with the increasing of coal prices. Power coal blending provides an effective way to solve these two problems. In some traditional methods, blended-coal properties were usually treated by the weighted average method which induced the optimization solutions deviating from the actual results. The reason is that different coal property indexes are based on different benchmarks; for example, the sulphur content in coal is based on applied basis, while the slagging properties of blended-coal are calculated on air-dried basis, which was influenced by the contents of moisture and ash in each coal. In order to study the effects, based on the genetic algorithm, a model considering these two factors was build up to optimum the coal-blending scheme. Compared with the traditional weighted average method, the new model got higher slagging property indexes, as means the former method may include some coal blending schemes into the optimizing process, in which the real slagging parameters go beyond constraint standards. Therefore, in the case of coal-blending optimization to prevent slagging in furnace, these two factors are especially important and should be considered carefully to ensure the precise of slagging parameters, so as to obtain the optimum results both in the prices of coals and in slagging property.

Observation of Pressure Drop Behavior in an Operating Fuel Cell Stack

Pressure drop on the cathode side of a PEM (Proton Exchange Membrane) fuel cell stack has been studied and used as a diagnostic tool. Since the Reynolds number at the beginning of the flow field channel was <250, the flow through the channel is laminar, and the relationship between the pressure drop and the flow rate is linear. Some departure from linearity was observed when water was either introduced in the stack or produced inside the stack in the electrochemical reaction. By monitoring the pressure drop in conjunction with the cell resistance in an operational fuel cell stack, it was possible to diagnose either flooding or drying conditions inside the stack.

Seawater Scrubbing for the Removal of Sulfur Dioxide in a Steam Turbine Power Plant

The most popular method of controlling sulfur dioxide (SO2) emissions in a steam turbine power plant is a flue gas desulfurization (FGD) process that uses lime/limestone scrubbing. Another relatively newer FGD technology is to use seawater as a scrubbing medium to absorb SO2 by utilizing the alkalinity present in seawater. This seawater scrubbing FGD process is viable and attractive when a sufficient quantity of seawater is available as a spent cooling water within reasonable proximity to the FGD scrubber. In this process the SO2 gas in the flue gas is absorbed by seawater in an absorber and subsequently oxidized to sulfate by additional seawater. The benefits of the seawater FGD process over the lime/limestone process and other processes are; 1) The process does not require reagents for scrubbing as only seawater and air are needed, thereby reducing the plant operating cost significantly, and 2) No solid waste and sludge are generated, eliminating waste disposal, resulting in substantial cost savings and increasing plant operating reliability. This paper reviews the thermodynamic aspects of the SO2 and seawater system, basic process principles and chemistry, major unit operations consisting of absorption, oxidation and neutralization, plant operation and performance, cost estimates for a typical seawater FGD plant, and pertinent environmental issues and impacts. In addition, the paper presents the major design features of a seawater FGD scrubber for the 130 MW oil fired steam turbine power plant that is under construction in Madinat Yanbu Al-Sinaiyah, Saudi Arabia. The scrubber with the power plant designed for burning heavy fuel oil containing 4% sulfur by weight, is designed to reduce the SO2 level in flue gas to 425 ng/J from 1,957 ng/J.

An Optimal Renewal Planning of Energy Supply System From Economic Viewpoint

An optimal planning method of renewal planning for energy supply systems is proposed to determine the proper renewal year and selection as to what kind of equipment is suitable for several types of buildings from economic viewpoint. In this method, they are determined together with maximum contract demands of utilities such as electricity and natural gas so as to minimize the annual total cost in consideration of system’s annual operational strategies corresponding to seasonal and hourly energy demand requirements during every evaluation year considered. A numerical study is carried out for an office building with a total floor area of 15 000m2, where the system is consisted of an electric refrigerator and a steam boiler. Through the numerical calculation, the influence of the following items are clarified on the optimal renewing year and selection of renewing equipment of the system by the parametric study; (a) upgrading technology of the equipment in the future; (b) initial capital cost of equipment; (c) renewing construction cost and trade-in value rate; and (d) interest rate.