Steam Cycle Power Plant

Keywords Gasification, Environmental Analysis, Fuel oil, Syngas feedstock. Steam cycle power plant... 

Using fuel oil as a feedstock in traditional steam cycle power plants... 

As a direct cycle gas turbine power plant, the GT-MHR has no intermediate or secondary circuits as would be associated with steam cycle power plants. To illustrate the primary components and their function in the power cycle, a simplified process flow diagram is provided in Fig. XV-2. 

Palmer, D.A, Benezeth, P., and Simonson, J.M. (2004) The solubility of copper oxides around the water/steam cycle. Power Plant Chem., 6, 81-88. 

Power plants based on the Rankine thermodynamic cycle have served the majority of the world s electric power generation needs in the twentieth century. The most common heat sources employed by Rankine cycle power plants are either fossil fuel-fired or nuclear steam generators. The former are the most widely used. 

As of the mid-1990s, many older conventional steam plants have been converted to combined cycle. The old boiler is removed and replaced by a combustion turbine and heat recovery steam generator. Although the cycle efficiency is not as high as completely new plants, substantial capital cost is avoided by the modification and reuse of existing steam turbine and auxiHary equipment. In many combined cycle power plants, steam is injected into the combustors of the combustion turbine to lower peak flame temperatures and consequendy lower NO. ... 

The Fossil Power Plants of the 1990s and into the early part of the new millennium will be the Combined Cycle Power Plants, with the gas turbine as being the centerpiece of the plant. It is estimated that between 1997-2006 there will be an addition of 147.7 GW of power. These plants have replaced the large Steam Turbine Plants, which were the main fossil power plants through the 1980s. The Combined Cycle Power Plant is not new in concept, since some have been in operation since the midl950s. These plants came into their own with the new high capacity and efficiency gas turbines. 

The new marketplace of energy conversion will have many new and novel concepts in combined cycle power plants. Figure 1-1 shows the heat rates of these plants, present and future, and Figure 1-2 shows the efficiencies of the same plants. The plants referenced are the Simple Cycle Gas Turbine (SCGT) with firing temperatures of 2400 °F (1315 °C), Recuperative Gas Turbine (RGT), the Steam Turbine Plant (ST), the Combined Cycle Power Plant (CCPP), and the Advanced Combined Cycle Power Plants (ACCP) such as combined cycle power plants using Advanced Gas Turbine Cycles, and finally the ITybrid Power Plants (HPP). 

In the area of performance, the steam turbine power plants have an efficiency of about 35%, as compared to combined cycle power plants, which have an efficiency of about 55%. Newer Gas Turbine technology will make combined cycle efficiencies range between 60-65%. As a rule of thumb a 1% increase in efficiency could mean that 3.3% more capital can be invested. However one must be careful that the increase in efficiency does not lead to a decrease in availability. From 1996-2000 we have seen a growth in efficiency of about 10% and a loss in availability of about 10%. This trend must be turned around since many analysis show that a 1% drop in the availability needs about 2-3% increase in efficiency to offset that loss. 

In a combined cycle plant, high steam pressures do not necessarily convert to a high thermal efficiency for a combined cycle power plant. Expanding the steam at higher steam pressure causes an increase in the moisture content at the exit of the steam turbine. The increase in moisture content creates major erosion and corrosion problems in the later stages of the turbine. A limit is set at about 10% (90% steam quality) moisture content. 

Kehlhofer, R.H., et al., Combined Cycle Gas Steam Turbine Power Plants, 2nd Edition, PennWell, Tulsa, Oklahoma, 1999. 

The code provides for the testing of gas turbines supplied with gaseous or liquid fuels (or solid fuels converted to liquid or gas prior to entrance to the gas turbine). Test of gas turbines with water or steam injection for emission control and/or power augmentation are included. The tests can be applied to gas turbines in combined-cycle power plants or with other heat recovery systems. 

Steam is passed through a number of tubes embedded in the nozzle or blades of the turbine. In many cases, the steam is bled from after the HP Steam Turbine of a combined cycle power plant and returned after cooling the gas turbine blades, where the steam gets heated in the process to the IP steam turbine. This is a very effective cooling scheme and keeps the blade metal temperature below 1250 °F (649 °C). 

Boyce, M.P., Performance Characteristics of a Steam Turbine in a Combined Cycle Power Plant, Proceedings of the 6th EPRI Steam Turbine Generator/ Workshop, August 1999. 

The steam electric power generation industry is defined as those establishments primarily engaged in the steam generation of electrical energy for distribution and sale. Those establishments produce electricity primarily from a process utilizing fossil-type fuel (coal, oil, or gas) or nuclear fuel in conjunction with a thermal cycle employing the steam-water system as the thermodynamic medium. The industry does not include steam electric power plants in industrial, commercial, or other facilities. The industry in the United States falls under two Standard Industrial Classification (SIC) Codes SIC 4911 and SIC 4931. 

Recent very successful demonstrations of the high efficiencies that can be achieved with combined cycle gas turbine-steam turbine power plants using pressurized, fluidized... 

The temperature in the core of the Earth—due to the decay of radioactive isotopes—is on the order of 4,000°C, the temperature of the lava of volcanoes is about 1,200°C, and the temperature of thermal springs can reach 350°C. If the groundwater temperature exceeds 150°C, flash steam power plants can be built, and if it is between 100 and 150°C, binary cycle power plants can be operated. 

Smaller combined-cycle power plants (up to 60-100 mW) are particularly suitable for cogeneration, because they can be located very close to the industrial steam user plant. 

In a combined-cycle power plant, electricity is produced by two turbines, a gas and a steam turbine. The term combined cycle comes from the fact that the combustion gas turbine operates according to the Brayton cycle and the steam system operates according to the Rankine cycle. As shown in Figure 2.115, the dual-shaft combined-cycle plant consists of a gas turbine (GT)... 

In this demonstration plant, the boiler feedwater can be preheated by geothermal heat if available. Depending on the availability and temperature of the geothermal heat in the area, the geothermal plant s design would vary. If the groundwater temperature exceeds 150°C (302°F), a "flash steam" power plant would be used, and if it is between 100 and 150°C (212 and 302°F), a "binary cycle" power plant would be used. 

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