The T-100-12.8 family of cogeneration steam turbines: Yesterday, today, and tomorrow

The T-100-12.8 turbine and its versions, a type of cogeneration steam turbines that is among best known, unique, and most widely used ones in Russia and abroad, are considered. A list of turbine design versions and quantities in which they were produced, their technical and economic indicators, design features, schematic solutions used in different design versions, and a list of solutions available in a comprehensive portfolio offered for modernizing type T-100-12.8 turbines are presented. Information about amounts in which turbines of the last version are supplied currently and supposed to be supplied soon is given.     

Modernization of exhaust hoods of low-pressure sections of steam turbines manufactured by the Ural Turbine Works

Issues of modernizing the current exhaust hoods of low-pressure sections for steam turbines manufactured by the Ural Turbine Works and designing new ones with the use of modern methods of computational fluid dynamics (ANSYS CFX) are considered. A flow in the exhaust hood is simulated numerically. Verification of obtained data is performed. The use of the finite volume method allowed the three-dimensional flow in the exhaust hood of turbines of the T-100 series to be analyzed and a simple variant for improvement of its characteristics to be developed. The project data on the novel design of the exhaust hood for the T-125/150-12.8 turbine are given.     

The longitudinal layout alternate version of cogeneration steam turbines with the generator placed on the side of the high-pressure cylinder

The schematic design of a cogeneration steam turbine with the generator placed on the side of the high-pressure cylinder is proposed. It is shown that the use of this solution is most promising for turbines with a longitudinal layout (like a T-175/210-12.8 turbine).     

K-65-12.8 condensing steam turbine

A new condensing steam turbine K-65-12.8 is considered, which is the continuation of the development of the steam turbine family of 50–70 MW and the fresh steam pressure of 12.8 MPa, such as twocylinder T-50-12.8 and T-60/65-12.8 turbines. The turbine was developed using the modular design. The design and the main distinctive features of the turbine are described, such as a single two-housing cylinder with the steam flow loop; the extraction from the blading section for the regeneration, the inner needs, and heating; and the unification of some assemblies of serial turbines with shorter time of manufacture. The turbine uses the throttling steam distribution; steam from a boiler is supplied to a turbine through a separate valve block consisting of a central shut-off valve and two side control valves. The blading section of a turbine consists of 23 stages: the left flow contains ten stages installed in the inner housing and the right flow contains 13 stages with diaphragm placed in holders installed in the outer housing. The disks of the first 16 stages are forged together with a rotor, and the disks of the rest stages are mounted. Before the two last stages, the uncontrolled steam extraction is performed for the heating of a plant with the heat output of 38–75 GJ/h. Also, a turbine has five regenerative extraction points for feed water heating and the additional steam extraction to a collector for the inner needs with the consumption of up to 10 t/h. The feasibility parameters of a turbine plant are given. The main solutions for the heat flow diagram and the layout of a turbine plant are presented. The main principles and features of the microprocessor electro hydraulic control and protection system are formulated.     

Reconstruction of the T-100-12.8 turbine with the use of reaction-type blades in high-pressure cylinders

Two versions of reconstructing a T-100-12.8 turbine with the use of advance technical decisions and modern methods of design are presented.     

The effectiveness of modernization of the low-pressure cylinder of the T-185/220-12.8 turbine

The basic principles of modernization of the low-pressure cylinder flow path of T-185/220-12.8 turbines are presented. It is shown that its implementation allows substantial increase in economic efficiency and reliability of the turbine unit operation in the condensation and cogeneration modes.     

Optimal design of the high-pressure cylinder flow path in updating the T-100-12.8 steam turbine

The discussion concerns some alternatives of updating the high-pressure cylinder (HPC) flow path of the T-100-12.8 turbine using an optimal design method that made it possible to find and realize means of enhancing the turbine efficiency. The effectiveness of using the advanced design solutions affording a high efficiency value of the HPC is demonstrated.     

Heat flow diagrams with and without a deaerator for steam turbine plants with T-250/300-23.5 turbines

A T-250/300-240 turbine (currently known as T-250/300-23.5), which is operated at 31 steam turbine plants, is the largest in the world extraction turbine (by the heating extraction load) and one of the largest by the nominal capacity. All steam turbine plants equipped with T-250/300-23.5 turbines of different modifications are operated in large cities of Russia and the neighboring countries covering a significant part of the needs of cities for the electric power and almost fully supplying them with heat power. The design life of a significant part of the operated steam turbine plants of this family is either expired or almost expired. It refers to both the turbine unit (including a turbine and a generator) and the turbine plant equipment. For steam turbine plants equipped with T-250/300-23.5 turbines, which were initially designed and mounted for work with deaerators at electric power stations, the heat flow diagrams with and without a deaerator were compared. The main advantages and disadvantages of each scheme were shown. It was concluded that, for the newly constructed power units with supercritical steam parameters, it is preferable to use the heat flow diagram without a deaerator; for the upgraded blocks, if there are no objective reasons for the removal of a deaerator, it is recommended to keep the existing heat flow diagram of a turbine plant.     

Recovery heat treatment of casing parts during modernization of turbines

The results of analyzing the experience from the recovery heat treatment (RHT) of the casing parts (HPCs, stop valves) of PT-60-12.8 and T-100-12.8 turbines, which was performed under factory conditions, is presented. It is demonstrated that the application of technology comprising two-stage normalization followed by high tempering is an effective technique for maintaining the operational efficiency of casing parts.     

Retrofitting of T-100/110-12.8 cogeneration steam turbines

Problems relating to replacement and retrofitting of steam turbines that have worked through their service life are considered, and methods for extending their service life are discussed. Concrete activities carried out at Ural Turbine Works in the course of renovating and retrofitting T-100/110-12.8 turbines are presented.     

Substantiation of the cogeneration turbine unit selection for reconstruction of power units with a T-250/300-23.5 turbine

The selection of a cogeneration steam turbine unit (STU) for the reconstruction of power units with a T-250/300-23.5 turbine is substantiated by the example of power unit no. 9 at the cogeneration power station no. 22 (TETs-22) of Mosenergo Company. Series T-250 steam turbines have been developed for combined heat and power generation. A total of 31 turbines were manufactured. By the end of 2015, the total operation time of prototype power units with the T-250/300-23.5 turbine exceeded 290000 hours. Considering the expiry of the service life, the decision was made that the reconstruction of the power unit at st. no. 9 of TETs-22 should be the first priority. The main issues that arose in developing this project—the customer’s requirements and the request for the reconstruction, the view on certain problems of Ural Turbine Works (UTZ) as the manufacturer of the main power unit equipment, and the opinions of other project parties—are examined. The decisions were made with account taken of the experience in operation of all Series T-250 turbines and the results of long-term discussions of pressing problems at scientific and technical councils, meetings, and negotiations. For the new power unit, the following parameters have been set: a live steam pressure of 23.5 MPa and live steam/reheat temperature of 565/565°C. Considering that the boiler equipment will be upgraded, the live steam flow is increased up to 1030 t/h. The reconstruction activities involving the replacement of the existing turbine with a new one will yield a service life of 250000 hours for turbine parts exposed to a temperature of 450°C or higher and 200000 hours for pipeline components. Hence, the decision has been made to reuse the arrangement of the existing turbine: a four-cylinder turbine unit comprising a high-pressure cylinder (HPC), two intermediate pressure cylinders (IPC-1 & 2), and a low-pressure cylinder (LPC). The flow path in the new turbine will have active blading in LPC and IPC-1. The information is also presented on the use of the existing foundations, the fact that the overall dimensions of the turbine unit compartment are not changed, the selection of the new turbine type, and the solutions adopted on the basis of this information as to LPC blading, steam admission type, issues associated with thermal displacements, etc.     

A T-113/145-12.8 cogeneration steam turbine for the PGU-410 combined-cycle plant at the Krasnodar cogeneration station

Turbine design, essential features of its control, economic indicators, and main solutions taken for the thermal circuit and layout of the T-113/145-12.8 turbine unit are considered.     

Assessment of the quality of reprofiling of T-100-12.8 turbine blades with the use of numerical simulation of a flow in plain turbine rows

Characteristics of blade profiles are presented that were developed in the course of modernization of the type T-100-12.8 turbine control stage by means of numerical simulation of viscous turbulent flow in plain rows.     

Cogeneration steam turbines from Siemens: New solutions

The Enhanced Platform system intended for the design and manufacture of Siemens AG turbines is presented. It combines organizational and production measures allowing the production of various types of steam-turbine units with a power of up to 250 MWel from standard components. The Enhanced Platform designs feature higher efficiency, improved reliability, better flexibility, longer overhaul intervals, and lower production costs. The design features of SST-700 and SST-900 steam turbines are outlined. The SST-700 turbine is used in backpressure steam-turbine units (STU) or as a high-pressure cylinder in a two-cylinder condensing turbine with steam reheat. The design of an SST-700 single-cylinder turbine with a casing without horizontal split featuring better flexibility of the turbine unit is presented. An SST-900 turbine can be used as a combined IP and LP cylinder (IPLPC) in steam-turbine or combined-cycle power units with steam reheat. The arrangements of a turbine unit based on a combination of SST-700 and SST-900 turbines or SST-500 and SST-800 turbines are presented. Examples of this combination include, respectively, PGU-410 combinedcycle units (CCU) with a condensing turbine and PGU-420 CCUs with a cogeneration turbine. The main equipment items of a PGU-410 CCU comprise an SGT5-4000F gas-turbine unit (GTU) and STU consisting of SST-700 and SST-900RH steam turbines. The steam-turbine section of a PGU-420 cogeneration power unit has a single-shaft turbine unit with two SST-800 turbines and one SST-500 turbine giving a power output of N _{el. STU} = 150 MW under condensing conditions.     

Experience Gained from Designing Exhaust Hoods of Large Steam Turbines Using Computational Fluid Dynamics Techniques

Experience gained from designing exhaust hoods for modernized versions of K-175/180-12.8 and K-330-23.5-1 steam turbines is presented. The hood flow path is optimized based on the results of analyzing equilibrium wet steam 3D flow fields calculated using up-to-date computation fluid dynamics techniques. The mathematical model constructed on the basis of Reynolds-averaged Navier–Stokes equations is validated by comparing the calculated kinetic energy loss with the published data on full-scale experiments for the hood used in the K-160-130 turbine produced by the Kharkiv Turbine-Generator Works. Test calculations were carried out for four turbine operation modes. The obtained results from validating the model with the K-160-130 turbine hood taken as an example were found to be equally positive with the results of the previously performed calculations of flow pattern in the K-300-240 turbine hood. It is shown that the calculated coefficients of total losses in the K-160-130 turbine hood differ from the full-scale test data by no more than 5%. As a result of optimizing the K-175/180-12.8 turbine hood flow path, the total loss coefficient has been decreased from 1.50 for the initial design to 1.05 for the best of the modification versions. The optimized hood is almost completely free from supersonic flow areas, and the flow through it has become essentially more uniform both inside the hood and at its outlet. In the modified version of the K-330-23.5-1 turbine hood, the total loss coefficient has been decreased by more than a factor of 2: from 2.3 in the hood initial design to a value of 1.1 calculated for the hood final design version and sizes adopted for developing the detailed design. Cardinally better performance of both the hoods with respect to their initial designs was achieved as a result of multicase calculations, during which the flow path geometrical characteristics were sequentially varied, including options involving its maximally possible expansion and removal of the guiding plates producing an adverse effect.     

Retrofitting Steam Turbines with Expired Service Life

Many pieces of equipment installed at thermal power stations (TPS) have an expired service life or are close to expiry and are obsolete. In addition, the structure of heat consumption by end users has changed. Among the ways for solving the problem of aging equipment is the retrofitting of turbines that allows for service life recovery and improvement of their performance to the modern level. The service life is recovered through replacement of high-temperature assemblies and parts of a turbine, and the performance is improved by retrofitting and major overhaul of low-temperature assemblies. Implementation of modern engineering solutions and numerical methods in designing upgraded flow paths of steam turbines considerably improves the turbine effectiveness. New flow paths include sabre-like guide vanes, integrally-machined shrouds, and effective honeycomb or axial-radial seals. The flow paths are designed using optimization and hydraulic simulation methods as well as approaches for improving the performance on the turbine blading and internal steam flow paths. Retrofitting of turbines should be performed to meet the customers' needs. The feasibility of implementation of one or another alternative must be determined on a case-by-case basis depending on the turbine conditions, the availability of reserves for generating live steam and supplying circulation water, and the demands and capacities for generation and delivery of power and heat. The main principle of retrofitting is to retain the foundation and the auxiliary and heat-exchange equipment that is fit for further operation. With the example of PT-60-130 and T-100-130, the experience is presented of a comprehensive approach to retrofitting considering the customer’s current needs and the actual equipment conditions. Due to the use of modern engineering solutions and procedures, retrofitting yields updating and upgrading of the turbine at a relatively low cost.     

Steam turbines of the T-50/60-8.8, K-63-8.8, and Tp-100/110-8.8 types destined for modernization of thermal power plants with K-50-90 and K-100-90 turbines

This paper describes the design, schemes of regulation, and control and protection of steam turbines of the T-50/60-8.8, K-63-8.8, and Tp-100/110-8.8 types destined for modernization of thermal power plants with replacement of K-50-90 and K-100-90 turbines that have very low efficiency and exhausted not only their designed, but also fleet life. The replacement proposed is based on state-of-the-art engineering solutions and will be carried out at concrete thermal power plants and CHP plants.     

K-330-23.5 steam turbine for replacing K-300-240 turbines of KhTGZ past their lifetime

A new K-330-23.5 steam turbine is presented. It is intended both for newly constructed power engineering installations and for replacing K-300-240 turbines that have exhausted their lifetimes. It is shown that this turbine can be used when reconstructing Kharkiv Turbogenerator Works K-300-240 turbines with installation of a new unit on the existing foundation.     

Refining the calculation procedure for estimating the influence of flashing steam in steam turbine heaters on the increase of rotor rotation frequency during rejection of electric load

A refined procedure for estimating the effect the flashing of condensate in a steam turbine??s regenerative and delivery-water heaters on the increase of rotor rotation frequency during rejection of electric load is presented. The results of calculations carried out according to the proposed procedure as applied to the delivery-water and regenerative heaters of a T-110/120-12.8 turbine are given.     

The T-120/130-12.8 and PT-100/130–12.8/1.0 cogeneration steam turbines produced by the ural turbine works for replacing turbines of the T-100 family

The basic design features and technical characteristics of the turbines installed on the foundation of the T-100 family turbines are presented.