Integrated approach to assessment of impact of beyond-design modes on operation of steam supply systems

2019 ◽  
Vol 12 (1) ◽  
pp. 10-17 ◽  
Author(s):  
A. I. Kiseleva ◽  
A. M. Fokin

The object of the study are the steam networks of Smolensk. The purpose of the article is to determine the influence of beyond-design modes on the functioning of the entire steam supply system. Beyond-design modes of industrial steam supply pose a serious problem for all elements of the system: they make it difficult to fully load the turbines, lead to high excess losses of heat and coolant, and also lead to disruption in technological processes. Analysis of statistical data on reduction of industrial steam extraction has been carried out, archived data on heat supply and consumption have been processed and analyzed over the period from 2007 to 2017. A methodological error is found in the accounting of thermal energy and coolant by variable pressure drop flowmeters designed to handle superheated and dry steam. Calculation of heat network quality indicators is carried out, maximum permissible lengths of steam pipeline sections are determined, enabling to transport superheated steam to consumer regardless of the load reduction. The influence of the extent of wear of insulation and the diameter of the pipeline on the change in the aggregate state of the coolant has been analyzed, and the maximum load for steam networks has been found as being 30% of the designed one. It has been established that, with industrial extraction decreased, the CHPP is forced to disengage the turbine from operation, since a load drop of more than 50% brings the turbine to the condensation mode and reduces the technical and economic performance of the CHPP to the threshold permissible values. The obtained results enable to draw a conclusion that such a problem as beyond-design modes, especially in steam supply systems, requires an integrated approach, since the influence on an individual element in isolation from the system leads to a change in the performance of the remaining elements.

1980 ◽  
Vol 45 (4) ◽  
pp. 1010-1035 ◽  
Author(s):  
Ondřej Wein ◽  
Václav Sobolík

A model is studied in the full range of all operational parameters of the unsteady plane flow of a power-law liquid induced by periodically variable pressure drop and oscillatory motion of the walls of a plane duct. Using the theory of similariry criteria of the asymptotic behaviour are formulated in four qualitatively different rheodynamic regimes. Corresponding asymptotic expressions are found for the degree of mechanical liquidization by the action of oscillatory shear stress superimposed on the principal steady state component. Theoretical results are illustrated using a set of experimental data on the gravitational flow along a vertical oscillating sheet.


2019 ◽  
Vol 139 ◽  
pp. 01078 ◽  
Author(s):  
A.G. Saidkhodjaev ◽  
A.M. Najimova ◽  
A.K. Bijanov

In this article, we propose a new method for determining the maximum load of electric consumers in urban electric networks, which differs from existing methods in more accurate and reliable determination of the maximum loads. Based on the determination of the maximum loads of the objects of urban electrical networks, it is concluded that the proposed methods are determined by high accuracy and minor errors.


2015 ◽  
Vol 10 (2) ◽  
pp. 214-228 ◽  
Author(s):  
Jos Frijns ◽  
Enrique Cabrera Marchet ◽  
Nelson Carriço ◽  
Dídia Covas ◽  
Antonio J. Monteiro ◽  
...  

There is significant potential for energy recovery through the use of micro-hydropower installations in water supply systems (WSS). To exploit the full potential of hydro energy in balance with the optimal hydraulic performance and water supply service, multi-objective management tools are needed. This paper presents the application of four management tools: (1) an energy audit to evaluate the potential hydro energy in the water pressurised systems of Alcoy; (2) multi-criteria decision-making methods for the selection of the preferred energy-efficient operation of a system with a pump-storage reservoir and hydro-turbines in the Algarve; (3) a numerical dynamic tool for optimal turbine operation in the water distribution of Langhirano; and (4) an urban water optioneering tool to estimate the hydropower potential of the external aqueduct network in Athens. These methods showed that through an integrated approach the WSS can be optimised for both hydraulic performance and hydro energy production.


2016 ◽  
Vol 5 (5) ◽  
pp. 64-74
Author(s):  
Шилков ◽  
Vladimir SHilkov ◽  
Аникин ◽  
Yu. Anikin

In this article, the necessity of integrated approach to the analysis and solution of problems of safety of water supply and wastewater treatment are declared. The results of the study the main problems of the systems of production of water supply and wastewater treatment are described. Practical measures for solving problems are proposed. Pressing need of application of means of informatization, strategic risk analysis methods and innovative technologies of water treatment are declared. The basic principles of safe and effective critical systems of water supply and wastewater treatment in the sphere of production are proposed.


2019 ◽  
Author(s):  
Chem Int

The effect of density, pressure drop, viscosity and orifice area on the characteristics of fluid flow was examined in this paper. Also studied was the effect on the control pressure change of the constant area variable pressure drop meter as a proportional derivative control. The mathematical model developed to monitor and predict the control of the system is given as P-Po = 7.8/t – 0.06 + Kc +Kd. The change in control pressure decreases with increase in proportional/derivative gain (Kc, Kd) as well as increase in time. The Bernoulli’s principle was applied in describing the design principle, stability analysis and development of mathematic model of a pressure-based flow meter with a constant area, variable pressure drop; using an orifice plate with different fluid flowing through it. The developed formula relates pressure drop with the flow rate of a given fluid passing through the orifice. The formula obtained is then simulated using different fluids. In order to control the flow rate, of these fluid flowing through the model developed was related to a Proportional Derivative control (PD). Thereby getting knowledge on how the PD controller performs with respect to different fluids, with change in pressure, density and area of the pipe/orifice was presented in this paper. Finally information and results on the simulation and how the PD controller functional parameters of proportional gain and derivative gain influence the control system was examined in this research.


2016 ◽  
Vol 17 (2) ◽  
pp. 381-388 ◽  
Author(s):  
D. Loureiro ◽  
H. Alegre ◽  
M. S. Silva ◽  
R. Ribeiro ◽  
A. Mamade ◽  
...  

Water utilities are aware of the water-energy loss relevance in supply systems. However, they still mainly focus on daily water loss control (real and apparent losses), without considering the impact on embedded energy. Moreover, they are mostly concerned with the economic dimension and, in most cases, tend to disregard the impact that water-energy loss may have on the quality of service, communication with the consumers, social awareness, water quality and environment. This paper focuses on the application of the developed and tested AWARE-P infrastructure asset management (IAM) methodology to improve water-energy loss management in water supply systems, while demonstrating the main benefits from implementing an integrated approach for water losses and related energy assessment. Results show that indeed the participating iPerdas utilities were able to define tactical measures leading to a more efficient and sustainable service.


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