Vol 64, No 3 (2017)

This article describes a methodological approach to defining indoor air temperature in buildings heated by a power supply unit consisting of a boiler house and a wind-driven power plant (WDPP). We discuss a heating option for a residential building in the windy conditions of Murmansk city. We proved that, during the periods of strong wind, a WDPP can partially or fully satisfy the heat demand and sometimes even create a surplus of energy. During low wind weather, almost all loads are handled by the boiler house. We considered a possibility to accumulate the surplus energy obtained from a WDPP during strong wind by increasing the temperature in the whole building up to 25°C and further using the accumulated heat during the lowwind period when indoor air temperature may fall below 20°C. This allows saving organic fuel in the boiler house. We demonstrated how indoor air temperature in the building may change throughout the year when using the surplus energy from the WDPP due to thermal storage capacitance of the building. We also provided the results of study, showing favorable energy-related effects of using a WDPP along with the boiler house. It was determined that engaging a WDPP in fulfilling the diagram of heating loads promotes the decrease in the boiler house’s contribution to heat supply by 30 to 50%, and using the surplus energy from the WDPP and thermal storage capacitance of the building allows reducing the contribution of the boiler house by 5–15% more in certain months.

Shock wave interaction with an adiabatic solid microparticle is numerically simulated. In the simulation, the shock wave is initiated by the Riemann problem with instantaneous removal of a diaphragm between the high- and low-pressure chambers. The calculation is performed in the two-dimensional formulation using the ideal gas equation of state. The left end of the tube is impermeable, while outflow from the right end is permitted. The particle is assumed to be motionless, impermeable, and adiabatic, and the simulation is performed for time intervals shorted than the time of velocity and temperature relaxation of the particle. The numerical grid is chosen for each particle size to ensure convergence. For each particle size, the calculated hydraulic resistance coefficient describing the particle force impact on the flow is compared with that obtained from the analytical Stokes formula. It is discovered that the Stokes formula can be used for calculation of hydraulic resistance of a motionless particle in a shock wave flow. The influence of the particle diameter on the flow perturbation behind the shock front is studied. Specific heating of the flow in front of the particle is calculated and a simple estimate is proposed. The whole heated region is divided by the acoustic line into the subsonic and supersonic regions. It is demonstrated that the main heat generated by the particle in the flow is concentrated in the subsonic region. The calculations are performed using two different 2D hydro codes. The energy release in the flow induced by the particle is compared with the maximum possible heating at complete termination of the flow. The results can be used for estimating the possibility of gas ignition in front of the particle by a shock wave whose amplitude is insufficient for initiating detonation in the absence of a particle.

The article deals with issues of technical and economic substantiation of priorities and scopes of modernizing the existing thermal power plants (TPPs) in Russia to work out long-term forecasts of the development of the industry. The current situation in the TPP modernization trends is analyzed. The updated initial figures of the capital and operation costs are presented and the obtained estimates of the comparative efficiency of various investment decisions on modernization and equipment replacement at gas-and-oil-burning and coal-fired TPPs with regard to the main zones of the national Unified Power System (UPS) of Russia are cited. The results of optimization of the generating capacity structure underlie a study of alternative TPP modernization strategies that differ in the scope of switching to new technologies, capital intensity, and energy efficiency (decrease in the average heat rate). To provide an integral economic assessment of the above strategies, the authors modified the traditional approach based on determination of the overall discounted costs of power supply (least-cost planning) supplemented with a comparison by the weighted average wholesale price of the electricity. A method for prediction of the wholesale price is proposed reasoning from the direct and dual solutions of the optimization problem. The method can be adapted to various combinations of the mechanisms of payment for the electricity and the capacity on the basis of marginal and average costs. Energy and economic analysis showed that the opposite effects of reduction in the capital investment and fuel saving change in a nonlinear way as the scope of the switch to more advanced power generation technologies at the TPPs increases. As a consequence, a strategy for modernization of the existing power plants rational with respect to total costs of the power supply and wholesale electricity prices has been formulated. The strategy combines decisions on upgrade and replacement of the equipment at the existing power plants of various types. The basic parameters of the strategy for the future until 2035 are provided.

Designs of various types of intermediate coolers of multistage ejectors are analyzed and thermal effectiveness and gas-dynamic resistance of coolers are estimated. Data on quantity of steam condensed from steam-air mixture in stage I of an ejector cooler was obtained on the basis of experimental results. It is established that the amount of steam condensed in the cooler constitutes 0.6–0.7 and is almost independent of operating steam pressure (and, consequently, of steam flow) and air amount in steam-air mixture. It is suggested to estimate the amount of condensed steam in a cooler of stage I based on comparison of computed and experimental characteristics of stage II. Computation taking this hypothesis for main types of mass produced multistage ejectors into account shows that 0.60–0.85 of steam amount should be condensed in stage I of the cooler. For ejectors with “pipe-in-pipe” type coolers (EPO-3-200) and helical coolers (EO-30), amount of condensed steam may reach 0.93–0.98. Estimation of gas-dynamic resistance of coolers shows that resistance from steam side in coolers with built-in and remote pipe bundle constitutes 100–300 Pa. Gas-dynamic resistance of “pipein- pipe” and helical type coolers is significantly higher (3–6 times) compared with pipe bundle. However, performance by “dry” (atmospheric) air is higher for ejectors with relatively high gas-dynamic resistance of coolers than those with low resistance at approximately equal operating flow values of ejectors.

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.

This study describes the results of simulation of the temperature field and the stress-strain state of membrane-type gastight water walls of boiler units using the finite element method. The methods of analytical and standard calculation of one-sided heating of fin-tube water walls by a radiative heat flux are analyzed. The methods and software for input data calculation in the finite-element simulation, including thermoelastic moments in welded panels that result from their one-sided heating, are proposed. The method and software modules are used for water wall simulation using ANSYS. The results of simulation of the temperature field, stress field, deformations and displacement of the membrane-type panel for the boiler furnace water wall using the finite-element method, as well as the results of calculation of the panel tube temperature, stresses and deformations using the known methods, are presented. The comparison of the known experimental results on heating and bending by given moments of membrane-type water walls and numerical simulations is performed. It is demonstrated that numerical results agree with high accuracy with the experimental data. The relative temperature difference does not exceed 1%. The relative difference of the experimental fin mutual turning angle caused by one-sided heating by radiative heat flux and the results obtained in the finite element simulation does not exceed 8.5% for nondisplaced fins and 7% for fins with displacement. The same difference for the theoretical results and the simulation using the finite-element method does not exceed 3% and 7.1%, respectively. The proposed method and software modules for simulation of the temperature field and stress-strain state of the water walls are verified and the feasibility of their application in practical design is proven.

Amines for a long time have been applied to maintaining water chemistry conditions (WCC) at power plants. However, making use of complex reagents that are the mixture of neutralizing and the filmforming amines, which may also contain other organic components, causes many disputes. This is mainly due to lack of reliable information about these components. The protective properties of any amine with regard to metal surfaces depend on several factors, which are considered in this article. The results of applying complex reagents to the protection of heating surfaces in industrial conditions and estimated behavior forecasts for various reagents under maintaining WCC on heat-recovery boilers with different thermal circuits are presented. The case of a two-drum heat-recovery boiler with in-line drums was used as an example, for which we present the calculated рН values for various brands of reagents under the same conditions. Work with different reagent brands and its analysis enabled us to derive a composition best suitable for the conditions of their practical applications in heat-recovery boilers at different pressures. Testing the new amine reagent performed at a CCPP power unit shows that this reagent is an adequate base for further development of reagents based on amine compounds. An example of testing a complex reagent is shown created with the participation of the authors within the framework the program of import substitution and its possible use is demonstrated for maintaining WCC of power-generating units of combined-cycle power plants (CCPP) and TPP. The compliance of the employed reagents with the standards of water chemistry conditions and protection of heating surfaces were assessed. The application of amine-containing reagents at power-generating units of TPP makes it possible to solve complex problems aimed at ensuring the sparing cleaning of heating surfaces from deposits and the implementation of conservation and management of water chemistry condition on the TPP equipment.