This application claims priority under 35 U.S.C. §119 to Italian Patent Application No. MI 2010 A 001599 filed in Italy on Sep. 3, 2010, the entire content of which is hereby incorporated by reference in its entirety.
The disclosure relates to steam turbine plants and to the integration of steam turbine plants designed and arranged for supplying intermediate steam to intermittent high demand steam consumers.
A challenge for single shaft steam turbine plants with steam off-takes for high demand users is to operate in an efficient manner while minimizing shaft peak torque stress. Peak torque can be created by the difference between the resistance created by a generator, for example, located on the shaft, and a series of steam turbines.
A carbon capture and sequestration unit in an example of a high demand steam consumer, is described in EP 1688173. Known steam turbine plant arrangements for the efficient supply of energy and steam to the high demand steam consumer are described in Zachary, J (June 2008), “Options for reducing a coal-fired plant's carbon foot print: Part I”, POWER 28-33 (Zachary). The described arrangements include single shaft steam turbines arranged in series with multiple low pressure steam turbines. U.S. Patent Application No. US 2010/0038917 discloses a single shaft steam turbine plant with intermediate off-takes for a high demand user.
A steam turbine plant is disclosed which includes a shaft with first and second ends, a first low pressure steam turbine and a second low pressure steam turbine at the first and second ends of the shaft respectively, a generator on the shaft between the first low pressure steam turbine and the second low pressure steam turbine; and a steam turbine train, on the shaft between the first and second low pressure steam turbines, the steam turbine train including at least one high-pressure steam turbine.
A method is disclosed of operating a steam turbine power plant which includes a shaft with first and second ends; a first low pressure steam turbine and a second low pressure steam turbine at the first and second ends of the shaft respectively; a generator on the shaft between the first low pressure steam turbine and second low pressure steam turbines; a steam turbine train, on the shaft between the first and second low pressure steam turbines, the steam turbine train including at least one high-pressure steam turbine; a first feed line, connecting the steam turbine train to the first low pressure steam turbine; and a first off-take, in the first feed line, for supplying steam to a high demand steam consumer, wherein the method comprises: identifying peak and non-peak electricity price periods, selectively operating and closing the first off-take valve to supply steam to a high-demand customer during a non-peak period and not supply steam to the high demand customer during a peak period.
A method is disclosed of operating a steam turbine power plant which includes: a shaft with first and second ends; a first low pressure steam turbine and a second low pressure steam turbine at the first and second ends of the shaft respectively; a generator on the shaft between the first low pressure steam turbine and second low pressure steam turbines; a steam turbine train, on the shaft between the first and second low pressure steam turbines, the steam turbine train including at least one high-pressure steam turbine; a first feed line, connecting the steam turbine train to the first low pressure steam turbine; and a first off-take, in the first feed line, for supplying steam to a high demand steam consumer, wherein the method comprises: identifying peak and high and low grid demand periods; and selectively operating and closing the first off-take valve to supply steam to a high-demand customer during a high and low grid demand periods and not supply steam to the high demand customer during a peak period.
Exemplary embodiments of the present disclosure are described more fully hereinafter with reference to the accompanying drawings, in which:
In the following description, for purposes of explanation, numerous specific details are set forth to provide a thorough understanding of exemplary embodiments. It will be evident, however, that embodiments may be practiced without these specific details. In other instances, structures and devices are shown in block form in order to facilitate description of the exemplary embodiments.
Throughout this specification, reference is made to “steam turbine trains.” Within this specification, a “steam turbine train” can be defined as a series of steam turbines of different pressure configurations on a single shaft 22. The steam turbine train 12 can include some or all of a series of steam turbines arranged on the single shaft 22
Throughout this specification, reference is made to “high demand steam consumer.” A “high demand steam consumer” can be defined as a steam consumer that is capable of demanding a steam rate equivalent to a low pressure steam turbine within the steam plant. An example of such a steam consumer is a carbon capture unit.
A single shaft steam turbine plant, configured for intermediate steam extraction, is disclosed that can limit the peak shaft torque through a high-pressure steam turbine of the plant throughout various modes of operation.
An exemplary embodiment of the disclosure provides a single shaft steam turbine with low pressure steam turbines at either end of the shaft. A generator and a high-pressure steam turbine is located between the low pressure steam turbines. This arrangement can ensure the total torque from the low pressure steam turbines does not pass through the high pressure steam turbine, thus enabling the shaft portion through the high pressure steam turbine to be designed for lower torque.
Exemplary embodiments provide clutches and intermediate user off take arrangements that can provide operational and maintenance flexibility.
Exemplary embodiments provide clutches and intermediate user off take arrangements that can provide operational and maintenance flexibility.
Reference will now be made to details of exemplary embodiments, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout in order to refer to the same or like parts.
By locating the low pressure steam turbine 30a and the generator 10 on opposite ends of the shaft 22, the torque load through the high-pressure steam turbine 14 can be reduced. To further reduce the torque load through the high-pressure steam turbine 14, in the steam train 12 shown in
In an exemplary embodiment, shown in
An exemplary embodiment provides a method of operating, for example, an electrical supply plant. The method first involves providing a steam turbine plant, as shown in the
In contrast, when a period of more moderate electricity prices is identified, the off-take(s) 24a, 24b to the high demand steam consumer is/are opened to supply, for example, a CO2 capture unit. During this operational mode, as steam is diverted from at least one of the low pressure steam turbines 30a, 30b electricity output of the power plant is reduced.
This exemplary method can optimize the profit of operating the steam turbine plant by maximizing electricity production during peak electricity prices, while maximizing CO2 capture during low electricity prices.
Alternatively, the off-take 24 and a CO2 capture plant may be operated during low grid demand as an alternative to operating at reduced feed rate to the medium-pressure steam turbine 16 and/or high pressure steam turbine 14 which can lead to a low efficiency operation. In this operating configuration, the power output can be rapidly increased by closing the off-take 24 and directing steam to the low pressure steam turbine 30a, 30b without the need to increase steam rates to the plant.
Although the disclosure has been herein described in what is conceived to be the most practical exemplary embodiments, it will be appreciated by those skilled in the art that the present disclosure can be embodied in other specific forms without departing from the essential characteristics thereof. For example, the describe steam turbines may be either single flow or double flow steam. Alternatively the low pressure steam turbines 30a, 30b may be sized differently in order to provided swallowing capacity so that the mass flow distribution between them may be matched to the demand of the steam consumer. The presently disclosed embodiments are therefore considered in all respects to be illustrative and not restricted.
Thus, it will be appreciated by those skilled in the art that the present invention can be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The scope of the invention is indicated by the appended claims rather than the foregoing description and all changes that come within the meaning and range and equivalence thereof are intended to be embraced therein.
Number | Date | Country | Kind |
---|---|---|---|
MI2010A1599 | Sep 2010 | IT | national |
Number | Name | Date | Kind |
---|---|---|---|
4519207 | Okabe et al. | May 1985 | A |
5051061 | Meylan | Sep 1991 | A |
5347814 | Kemmer et al. | Sep 1994 | A |
7317268 | Bray et al. | Jan 2008 | B2 |
20030175117 | Klaus et al. | Sep 2003 | A1 |
20060182621 | Laskaris et al. | Aug 2006 | A1 |
20090107532 | Lonne et al. | Apr 2009 | A1 |
20100038917 | DiAntonio et al. | Feb 2010 | A1 |
Number | Date | Country |
---|---|---|
1 551 257 | Feb 1970 | DE |
141 335 | Apr 1980 | DE |
692 20 240 | Jan 1998 | DE |
0 374 645 | Jun 1990 | EP |
1 335 110 | Aug 2003 | EP |
1 688 173 | Aug 2006 | EP |
100369 | Apr 1917 | GB |
102741 | Jun 1917 | GB |
108118 | Jul 1917 | GB |
Entry |
---|
Italian Search Report (EPO Form 1503) dated Jun. 15, 2011. |
Italian Written Opinion (Form IT237) dated Sep. 3, 2010. |
Justin Zachary, “Option for reducing a coal-fired plant's carbon footprint: Part I”, Bechtel Power Corp., Jun. 15, 20089 pages. |
German Search Report issued Jul. 20, 2012 in corresponding German Patent Application No. 10 2011 111 707.9. |
Number | Date | Country | |
---|---|---|---|
20120223532 A1 | Sep 2012 | US |