Combined cycle equipment

It will be some time before fuel cells become available as a realistic commercial alternative for power generation applications. In order to compete with modem gas turbines/combined-cycle equipment, fuel cell plants will have to produce high-temperature waste heat, operate at an electrical efficiency of... 

Today, the planned installation of new oil fired steam boilers is essentially nil. Table II shows that approximately 96,000 mw of capacity will remain in place in 1987. These units were put into service primarily in the mid-1960fs and have 10-30 years of useful life remaining. Installed capacity of liquid fueled combined cycle units is expected to grow from 3000 to 8000 mw over this time period. These units generate electricity more efficiently than conventional boilers. Combined cycle capacity is projected to be utilized much more extensively than in the past. As a result, the anticipated quantity of power generated from combined cycle equipment may increase nine-fold from 4,000 to 36,000 million Kilowatt hours as shown in Table III. Unfortunately, the future use of petroleum liquids for this kind of operation has been jeopardized by the recently legislated Fuel Use Act. This Act requires coal to be used instead of petroleum for new power stations. 

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. ... 

Because fuel costs are high, the search is on for processes with higher thermal efficiency and for ways to improve efficiencies of existing processes. One process being emphasized for its high efficiency is the gas turbine combined cycle. The gas turbine exhaust heat makes steam in a waste heat boiler. The steam drives turbines, often used as lielper turbines. References 1, 2, and 3 treat this subject and mention alternate equipment hookups, some in conjunction with coal gasification plants. 

Interest is increasing in running units at elevated pressures (6-15 atm) in order to reduce equipment size, lower emissions, reduce sorbent requirements, and increase the thermal efficiency by using a gas turbine in addition to a steam turbine in a combined cycle. There is also a trend away from bubbling beds and toward circulating beds, which use finer solids and higher velocities and are able to use sorbents more efficiently. 

A modern synthesis gas plant can be coupled to a gas/steam combined cycle. The gases could in a future installation be consumed at enhanced efficiency by a hybrid fuel cell/combined cycle plant, notably if the fuel cells were equipped with concentration cell circulators. See Section 5.2.13. 

Electricity costs are projected by H2Sim for advanced coal, combined cycle natural gas, natural gas combustion turbines, nuclear, wind, solar thermal, and solar photovoltaic (PV). Projected prices are for the production costs from plants built in 2020 and equipped with the best... 

There are a number of technological concepts that fall under the umbrella of clean coal, including installation of air pollution control equipment, and more innovative ideas such as carbon capture and gasification of coal for use in combined-cycle plants similar in design to natural gas-fired power plants. There is also the potential for producing synthetic liquid fuels from coal as means of... 

Many of the gas turbines applied in electric utility combined-cycle service are supphed as part of a complete package by the gas turbine manufacturer. The manufacturer supphes or specifies aU the major equipment, such as heat-recovery steam generators (HRSGs), steam turbines, and plant controls, to optimize plant performance through an integrated approach. Table 6.24 lists typical performance specifications for three versions of combined cycles based on the MS7001E gas turbine. 

Table 3.8 compares the estimated costs of potable water production through seawater desalination cogeneration with conventional and VHTR power plants (Sato et al., 2014). The conventional plant is based on a modem gas turbine combined cycle (GTCC) power plant at 55% power generation efficiency. The VHTR cogeneration system is that described in Section 3.4.2.2. The costs were evaluated by an original equipment manufacturer (OEM) vendor active in the Middle East desalination plant constmction. The vendor carried out the plant equipment design and evaluated the required operation and maintenance. The cost estimation was then developed based on the vendor construction and operation know-how of comparable-scale MSF plants. 

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