Vízügyi Közlemények, 1987 (69. évfolyam)

2. füzet - Kardos Imre-Pálfai Imre-Török József: Geotermikus energiahasznosítás az Alsó-Tisza vidékén

234 Kardos /., Pálfai I. és Török J. Utilization of geothermal energy in the Lower Tisza Valley area by I. KARDOS, С. E.-Dr. I. PÁLFAI, С. E.-Dr. J. TÖRÖK, С. E. In investigating the area of the Lower Tisza Valley Regional Water Authority-about 8500 km

2 large-the authors compiled first the history of development in the utilization of geothermal energy. Increase of the number of hot-water wells is demonstrated in Fig. 2. The sand and sandstone layers storing hot water are several hundred meters thick in this area. Their depth is around 1500 to 2100 meters (Fig. 3). Piezometric levels in the wells are usually 10 to 20 meters above the ground level-especially in the central part of the region-where exploitation is practically performed by free flow. The amount of this specific water resource exceeded-in the most favourable cases-the value of 50 m

3/d.km

2. Exploited discharges per well were between 1.0 and 2.5 m

3/min. Due to dwindling pressures in the layers, the discharges of the wells decreased continuously and pumping was introduced at several places. The temperature of water fluctuated between 90 and 100 °C in the deepest wells. Fig. 8 was drawn on the basis of Figs. 4 and 7. It shows the areal distribution of the utilization of free-flow geothermal energy with the assumption that the usage of energy was uniformly possible down till 30 °C. The dissolved salt-content of thermel waters is from 2000 to 3000 g/m

3 (Fig. 9). The salts are of the type of alkaline-hydrogen-carbonate. At Уз of the wells precipitated scale was often observed and some contained not negligible amounts of dispersed metane gas. Followingly, the present situation and recent experiences were summarized by the authors gained on the utilization of geothermal energy. Communal utilization occurred mostly in public bathes (Fig. 10). At some places, however, (Szeged, Hódmezővásárhely, Szentes) flats and sanitary facilities were also heated by thermal water (Fig. 11). In industry, thermal waters were used to heat workshop-halls, to produce flax and exploit hydrocarbon (water recharge). Utilization was most impressive in agriculture (Fig. 12). The main data (heating of glass-houses, of plastic tents) were compiled in Table II. In the investigated area 36 million m

3 thermal water has been produced in 1985, out of which 13 million m

3 needed pumping (Fig. 13). Altogether 80 percent of the available amount of thermal water has been utilized for different purposes but only 60 percent of the obtainable temperaturedegree could be attained setting-in this way-the efficiency of energy-use to about 50 percent. In order to save money, 27 wells-dead in the production of hydrocarbon-were opened for thermal water exploitation. The disposal of used thermal waters is not an easy task due to their high salt-content, especially in cases when drainage and irrigation systems are combined. In order to avoid the mixing of thermal waters and irrigation waters several reservoirs were built to store thermal waters. In Szeged and Hódmezővásárhely attempts are made to recharge the used amounts of thermel waters in the different soil layers. This solution would serve-in the mean time-the preservation of layer-energy, as well. * * * Utilisation de 1' énergie géothermique dans la région de la vallée aval de la rivière Tisza par. KARDOS I.-Dr. PÁLFAI I.-Dr. TÖRÖK J. Les auteurs récapitulent Г histoire de développement de Г utilisation de Г énergia géothermique concernant la circonscription (Fig. 1.) d'activité de 8500 km

2 de la Direction Hydraulique de la Vallée Aval de la Tisza. L' accroissement du nombre des puits thermaux est représenté sur la Figure 2. Les couches aquiféres thermales sableuses et de grés ont une épaisseure de plusieures centaines métrés. Leur profondeure varie généralement de 1500 à 2500 métrés (Fig. 3.). Dans la partie centrale de la région étudiée les niveaux en repos des puits généralement sont de 10 à 20 métrés au dessus