Analysis of efficiency of feed pump control by changing rotation of rotor for power plants of various types

Abstract

The type of power plant feed pump drive is selected in the course of a feasibility study. Domestic experience is based on recommendations that have been obtained in the middle of the last century when fuel was relatively cheap. These recommendations are currently being revised. Manufacturers of technological tools of pumps frequency control offer to install fluid couplings, variable frequency electric drives or drive turbines for power plants of various types. At the same time, they declare the high efficiency of such solutions. But the effect is often calculated based on energy savings indicators for the pump drive without considering changes of the operating modes of other equipment of the power plant. An urgent task is a comprehensive assessment of the effectiveness of the measures under consideration. This assessment should consider the objective parameters and modes of facilities operation, as well as interrelation of power electricity cost for own needs and loads of the basic equipment. To determine the technical effect of application of various methods of frequency control of feed pumps, models are used that are developed on the individual basis for each power plant based on the energy characteristics of the equipment. These models include algorithms for heat and electrical balances. Operational characteristics of the feed pumps and performance assessment are calculated according to the known techniques. Based on a unified methodological approach, the authors have developed mathematical models of condensing power supply units and combined heat and power plants for an initial pressure of 12,8 MPa. These models make it possible to determine the effect of frequency control of feed pumps based on data for real time in operation considering the interrelation of power electricity cost for own needs and loads of the basic equipment. Calculation of index of performance of application of various means of frequency control of feed pump performance have been carried out. It is revealed that to assess the efficiency of application of technological tools of frequency control of feed pumps, it is of decisive importance to consider the experience of equipment load, load schedules, the interrelation of power electricity cost for own needs and loads of the basic equipment. No general recommendations to use certain methods of feed pumps control are applicable, when conducting such an assessment.