Advanced Technologies Supporting Environmentally Conscious Thermal Power Plants
Fossil-Fuel Power Plants in Low-Carbon Society
Advanced Technologies Supporting Highly Efficient Thermal Power Plants
In the field of thermal power generation, practical realization of carbon dioxide (CO2) capture and storage (CCS) systems as well as highly efficient thermal power plants are required to reduce greenhouse gas emissions. In addition, thermal power plants optimized to balance load fluctuations in the electricity grid caused by natural power generation facilities, such as wind and solar power installations, are also required.
In response to a broad range of market needs, Toshiba has been providing a wide variety of equipment and services through the following technological advancements: (1) technologies for highly efficient thermal power systems, (2) control technologies for flexible load changeability, (3) technologies for rehabilitation and monitoring systems, and (4) CCS technologies.
High-Efficiency Technologies for Thermal Power Plant Steam Turbines
TAKAHASHI Takeo / TAKAHASHI Toru / OKITA Nobuo
Thermal power generation has the characteristic of permitting flexible responses to fluctuations in power demand. In order to reduce carbon dioxide (CO2) emissions by thermal power plants, enhancement of their thermal efficiency is required.
Toshiba has been engaged in the development of high-efficiency steam turbines for thermal power plants using various technologies including state-of-the-art computational analysis and test facilities such as its steam turbine development facility for the reduction of internal losses in steam turbines. Furthermore, we have been developing a 700°C-class advanced ultra-supercritical (A-USC) steam turbine with the aim of realizing higher thermal efficiency.
Dissimilar Welded Rotors for Large-Capacity High-Temperature Steam Turbines
ASAI Satoru / SAITO Kazuhiro / MURAKAMI Itaru
Toshiba has been developing a large-capacity high-temperature steam turbine to realize highly efficient, environmentally conscious power generation systems. We have also been engaged in the development of a welded rotor for steam turbines in response to the market demand for short delivery times in recent years.
We have now developed a welding method to fabricate dissimilar welded rotors, composed of modified 12% chromium (Cr) steel and chromium-molybdenum-vanadium (CrMoV) steel, for high- and intermediate-pressure (HIP) turbines. The joint strength and thermal stability of the newly developed welded rotor, as well as the applicable inspection technique, have been verified through tests. As a result, the rotor has been applied to the high-pressure (HP) turbine of Sigma Power Ariake Co., Ltd.'s Mikawa Power Plant Unit 2, where its successful performance has been confirmed under actual machine conditions.
Insulation System Realizing Environmentally Conscious Stator Coils with High Thermal Conductivity for High-Efficiency Turbine-Driven Generators
KOBAYASHI Masashi / HATANO Hiroshi / NAKAMURA Hideyuki
The recent enhancement of awareness regarding global environmental change has led to the development of high-efficiency turbine-driven generators, which are considered to be a means of reducing the environmental burden of various manufacturing processes.
Toshiba has been developing a high-efficiency, large-capacity, turbine-driven generator employing an indirectly hydrogen-cooled stator coil that has so far been used for turbine-driven generators with an intermediate capacity of up to the 400 MVA class. As a result of these efforts, we have developed a new insulation system that has made it possible to realize stator coils with high thermal conductivity. A 670 MVA indirectly hydrogen-cooled turbine-driven generator applying this insulation system has achieved 0.1% to 0.2% higher efficiency compared with conventional generators. In addition, the development of this environmentally conscious insulation system has reduced the amount of waste materials produced by and improved the working environment for the manufacturing of stator coils.
Information and Control Technology to Improve Efficiency and Operation of Thermal Power Plants
TANI Akinori / KUBO Takashi
As renewable energy resources such as wind, solar, and other natural energies are subject to natural conditions, their output power fluctuates in accordance with external factors. Thermal power generation systems are expected to compensate for such fluctuations and stabilize the grid system due to the improvement of their load response.
Toshiba has been developing new technologies to improve the load response of thermal power plants by optimally controlling the main steam pressure and temperature. Furthermore, in order to operate thermal power plants more efficiently, we have developed a new control system utilizing information and control technology that can provide various information and functions to operators, including plant performance surveillance, plant abnormal status prediction, and so on, based on the historical data of the plant.
Engineering for Rehabilitation of Thermal Power Plants in Eastern Europe
TAJIRI Junichi / TANAKA Katsuaki
Following the conclusion of its first contracts for the rehabilitation of aging thermal power plants in Eastern Europe, Toshiba has been implementing rehabilitation projects in Romania and Bulgaria. Rehabilitation of the Paroseni Thermal Power Plant in Romania has already been completed, and a rehabilitation project at the Maritsa East II Thermal Power Plant in Bulgaria, in which a total of six turbine-driven generator units are planned to be replaced, is in progress. Rehabilitation of four of these units has been completed, and work on the remaining two units is under way.
Although engineering delays caused by both lack of information on existing equipment and differences in business practices such as complicated certification systems have occurred frequently in these Eastern European projects, we have been making efforts to minimize delays in the project schedules by taking advantage of our practical experience in rehabilitation project management and engineering.
Efficient Maintenance Service for Overseas Power Plants Utilizing ICT
ISHIKAWA Tetsuro / NISHIMURA Mariko
Immediate and appropriate responses to customers' inquiries and actual problems related to power plant operations, as well as the prediction and prevention of problems by the monitoring of operations, are essential to secure the stability of commercial power generation.
As a solution to this issue, Toshiba has been offering a continuous service agreement (CSA) for overseas power plants that it has delivered. The CSA can provide immediate and appropriate responses to problems by obtaining information on the status of the power plant in question through information and communication technology (ICT) and Web-based systems. It can also detect the symptoms of some problems including rubbing, insufficiency of lubricating oil, and so on before a critical problem such as turbine damage occurs, by continuously monitoring the steam turbine vibration.
Validation Testing of Carbon Dioxide Capture Pilot Plant Using Flue Gas of Coal-Fired Thermal Power Plant
KITAMURA Hideo / EGAMI Norihide / OHASHI Yukio
Coal reserves are relatively rich and widely distributed around the world compared with other fossil fuels such as oil and liquefied natural gas (LNG). Coal therefore has advantages in terms of stable supply and low cost as a fuel for power generation. However, the carbon dioxide (CO2) emissions per unit of electricity generated by coal are larger than those of other fossil fuels. The development of technology for separation and capture of CO2 from the flue gas of coal-fired thermal power plants is thus required from the standpoint of global warming prevention.
Toshiba has been developing a post-combustion capture (PCC) method using chemical absorption, which is suitable for CO2 capture from large volumes of flue gas and can be applied to not only newly constructed but also existing power plants. We constructed a 10 tons-CO2/day-scale pilot plant at the Sigma Power Ariake Co., Ltd.'s Mikawa Power Plant in September 2009, and have been conducting test operation to verify the performance of the system using actual flue gas.