Repowering of steam power plants for medium-high increase of power generated

The repowering of steam power plants by overlapped gas turbine units is discussed. The analysis has been performed on a particular arrangement of the two power plants: steam at medium pressure is produced in a proper recovery boiler fed by the exhaust of a gas turbine unit and it expands into the medium-low pressure steam turbine of the pre-existing plant in addition to the main steam flow. This solution involves a simple layout, very few modifications to the pre-existing components and a good compromise between performance and efficiency for medium-high increase of power generated (power ratio GT/ST about 0.3 ÷ 0.5). The thermodynamic effects produced by these operations and the behavior and performance of the repowered plant are analyzed, and the results are presented and discussed

On the effects of heat recoveries discharged into steam power plants

It is noted that energy saving operations realized at steam power stations connected with industrial plants as well as steam plant repowering involve the discharge of heat recoveries and their interaction with preexisting plant components. The authors present some criteria for the analysis of steam plant performance characteristics and the respective results on the effects produced by these heat recoveries. A parametric analysis was carried out, taking into account the main schemes of steam power systems and layout, size, and design performance. In particular, the influence of the following parameters was analyzed: preexisting layout and size of plant; quantity, quality (i.e., temperature), and location of heat recoveries discharged into the plant; and plant working conditions (nominal and partial load)

A procedure for monitoring and control of condenser losses in steam power stations

In this paper a method for evaluation of losses caused by condenser efficiency reduction in steam power stations is presented. The procedure allows the evaluation of the effects caused either by the reduction of cooling water flow rate or by decrease of condenser heat exchange (fouling); moreover it allows the evaluation of the consequent variation in the condensing pressure (temperature) and the increased energy losses as heat consumption increase of the thermal process. The method is based on the comparison of the real (measured) data with design data 'corrected' by derating conditions

Maintenance management and organization

Maintenance management is a relatively new field and the corresponding body of knowledge is continuing to grow (Visser, 2002). For example, in Europe, two technical committees of the Comité Européen de Normalisation (CEN) are currently adding to the body of knowledge terminologies, guidance to prepare agreements, control systems for maintenance management, and other development directions (CEN, 2008). In particular, CEN Technical Committee 319 deals specifically with maintenance. They have published one standard (EN 15341) that provides maintenance management with the support of a control system (made up from more than 70 indicators) to achieve maintenance excellence and to competitively use technical assets, regardless of industry. Moreover, this committee has been addressing the issues of defining a maintenance management general framework (including buildings) through a standard currently in progress and identifying three very promising development directions (i.e., responsibilities in maintenance; identification, classification, and costs in maintenance actions; and maintenance in the healthcare industry). © 2009 Springer London

Internal combustion steam cycle (G.I.ST. cycle): Thermodynamical feasibility and plant lay-out proposals

In this paper a new kind of steam cycle provided with internal combustion is proposed. The internal combustion of natural gas and compressed air inside the steam flow has been conceived to carry out a steam heating (SH a/o RH) until TIT (Turbine Inlet Temperature) much higher than those of the conventional steam power plants. By this internal combustion it seems possible to overcome the present limits to TIT in steam plants which are, as known, especially related to the technological problems of the superheater tube materials in the conventional external combustion steam boilers. The proposed cycle has been named with the acronym GIST (Gas Injection STeam) since the hot gases resulting from a combustion close to stoichiometric conditions are injected inside the steam flow. This paper provides a first critical approach to these new kinds of thermodynamical cycles. At the first the thermodynamical and technological problems related to the combustion inside steam are explained and discussed. Then, different plant lay-out solutions are proposed with a critical discussion on their overall performance. At the last two GIST solution have been defined that seem very interesting: the first is an hybrid plant scheme (i.e. provided with multi-fuel supply) which involves performances higher than conventional steam power plants (net electric efficiency of about 47%); the second is a plant scheme with full natural gas supply (i.e. without multi-fuel steam boiler) which involves very relevant performances (net electric efficiency of about 57%)

Efficient Supply Chain Management: Traceability and Transparency

The development of SCM systems is a difficult activity, since it involves integrating critical business flows both within and among participating companies. The inherently difficulty of the problem is exacerbated by the business constraint (that almost invariably applies in the real world) that the investments made by individual companies throughout the years must be preserved. This maps to major design constraints, since SCM systems must be built around the preexisting ICT infrastructures of the individual companies and- A lso importantly-without affecting the local policies. We propose a federation-based approach to seamless and effective integration of legacy enterprise information systems into a unified SCM system. The proposed solution is implemented using a combination of Open Source BPM and cloud computing platform, and validated with respect to a real world use case taken from a research activity (namely: The GLOB-ID project) conducted cooperatively by academic and industrial parties