THE DISS PROJECT : DIRECT STEAM GENERATION IN PARABOLIC TROUGHS OPERATION AND MAINTENANCE EXPERIENCE UPDATE ON PROJECT STATUS
The DISS (DIrect Solar Steam) project is a complete R+TD program aimed at developing a new generation of solar thermal power plants with direct steam generation (DSG) in the absorber tubes of parabolic trough collectors. During the first phase of the project (1996-1998), a life-size test facility was implemented at the Plataforma Solar de Almería (PSA) to investigate under real solar conditions the basic DSG processes and evaluate the open technical questions concerning this new technology. This paper updates DISS project status and explains O&M-related experience (e.g. main problems faced and solutions applied) with the PSA DISS test facility since January 1999. NOMENCLATURE DAS Data acquisition system DISS Direct solar steam (the project) DSG Direct steam generation (the process) PSA Plataforma Solar de Almería P Pressure T Temperature INTRODUCTION Solar thermal power plants based on parabolic trough collectors are presently the most successful solar technology for electricity generation, as demonstrated by the SEGS plants in California. Direct steam generation in the absorber tubes is seen as a promising option to further the competitiveness of this technology. Replacement of the oil by direct steam generation results in lower investment and operating costs, as well as reduced environmental risk and fire hazards in case of leaks. Simultaneously, the performance can be improved by avoiding the thermodynamic losses associated with the oil water/steam heat exchanger of the SEGS plants. In combination with further improvements of the collector field and overall system integration, a 26% reduction in the electricity cost seems to be achievable (Langenkamp, 1998). Taking into consideration this expected benefit, a group of German and Spanish partners, with the financial support of the European Commission JOULE Programme, started in 1996 the DISS (Direct Solar Steam) project, which is an R+D program aimed at developing a new generation of solar thermal power plants with parabolic trough collectors. Expected improvements are based on three main factors: 1. Development and implementation of improved components for parabolic trough collectors (e.g. new, more economical absorber tubes with good optical and thermal properties; cheaper sun-tracking systems; better mirrors, etc...). 2. Development of the Direct Steam Generation (DSG) process to eliminate the oil used at the existing solar thermal plants as a heat carrier from the solar field to the power block. Since the DSG process is a promising way
Control de Campos de Colectores Solares
El presente trabajo se ha desarrollado gracias a la financiacion del Ministerio de Educacion y Ciencia, a traves de los proyectos CICYT-FEDER DPI2004-07444-C04-04, DPI2004-01804, DPI2004-06419 y por la Consejeria de Innovacion, Ciencia y Empresa de la Junta de Andalucia. 
En el articulo se resumen diversos esquemas de control que se han desarrollado en colaboracion con otros colegas del Departamento de Ingenieria de Sistemas y Automatica de la Universidad de Sevilla, fundamentalmente Carlos Bordons, Francisco Gordillo, Manuel R. Arahal, Manuel G. Ortega, Julio Normey y Mercedes Perez de la Parte. Este trabajo se ha realizado tambien en el ambito de los proyectos de la Union Europea “Enhancement and Development of Industrial Applications of Solar Energy Technologies”, dentro del programa “Human Capital and Mobility - Large Installa-tions Program”, EC-DGS XII Program “Training and Mobility of Researchers - TMR” y EC-DGSXII program “Improving Human Potential - IHP”y promovido por CIEMAT - PSA y del acuerdo especifico de colaboracion entre la Plataforma Solar de Almeria y el Grupo de Investigacion “Automatica, Electronica y Robotica” de la Universidad de Almeria (TEP197) titulado “Desarrollo de sistemas y herramientas de control para plantas termosolares”.
Research on velocity distribution in semi-dry flue gas desulfurization tower
As an accurate high-quality instantaneous measurement technology, particle image velocimetry (PIV in acronym) has applied widely in single-phase flow and multiphase flow. The velocity distribution in semi-dry FGD tower directly influences gas-solid mix and contact situation. In base of the tower, gas-solid two-phase flow field is more complex, and has the quite tremendous influence to the overall system desulphurization efficiency. This paper utilized PIV to study velocity distribution in Semi-dry flue gas desulfurization tower and obtained velocity distribution.