Ana-Maria BianchiSorin DimitriuFlorin BltreuTHE ENERGETIC RECOVERY OF THE COMBUSTIBLE GASES FROM GEOTHERMAL WATERSby

The Commission should assess to what extent Member States have made progress towards achieving their national indicative targets, and to what extent the national indicative targets are consistent with the global indicative target of 12 % of gross domestic energy consumption by 2010 (DIRECTIVE 2001/77/EC OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL)

Ponderea energiei electrice produse din surse regenerabile de energie la consumul naional brut de energie electric urmeaz s ajung la 33% pan n anul 2010. Prevederile prezentei hotrri se aplic energiei electrice produse din urmtoarele surse de energie regenerabile: energie hidro produs n centrale cu o putere instalat mai mic sau egal cu 10 MW, puse n funciune sau modernizate ncepnd cu anul 2004, energie eolian, solar, geotermal, biomas, a valurilor, precum si hidrogen produs din surse regenerabile de energie.

(HG 958/2005)

The geothermal potential of Romania for energetic utilizationsAnnual geothermal potential: cca. 3106 MWh/year (240.000 ept/year)

Number of functioning drills: cca. 60

Utilized potential: cca. 2106 MWh/year (170.000 ept/year)

Temperature level: 55 ... 115 oC

The geothermal energy zoning on the territory of Romania

Olt Valley working geothermal perimeter

The basic scheme of the geothermal water utilization in the SPA hotels.

The estimation of necessary of thermal energy in Calimanesti TownNumber of permanent habitants: 8500Number of conventional apartments connected

to centralized heating system (oct. 2009): 530 Maximal thermal load for heating: 3500 kWMaximal thermal load for domestic hot water: 500 kW

The characteristics of the geothermal water drill:

Maximal available water flow: 10 l/s Maximal available temperature: 95 oC Minimal available temperature

to the heat exchangers outlet: 50 oC

The basic scheme of the actual geothermal station

Composition and ratio of gases associated with geothermal water.

Composition and ratio of gases associated with geothermal water(Nm3/m3 water)Water wellCaciulataWater wellCoziaWater wellCalimanestiThe water well working parameters during the sample gatheringVol. flow32,4 m3/hGas temp.87 oCVol. flow57,6 m3/hGas temp.89 oCVol. r flow28,8 m3/hGas temp.85 oCNitrogen (N2)0,26380,29280,3254Carbon dioxide (CO2) 0,02470,01980,0264Methane (CH4)2,15611,65452,2389Ethane (C2H6)0,02000,01290,0193Propane (C3H8)0,00420,00320,0028i-Butane (C4H10)0,00020,00080,0003n-Butane (C4H10)0,00070,00100,0003Total ratio from which:Combustible gases ratio2,46972,18 (88%)1,98501,67 (84%)2,64042,26 (86%)Heating value (MJ/Nm3)31,730,530,6

The raw energetic potential possible to be recovered from gases associated with geothermal water

Geothermal water wellWater volume flowGas ratioGas temp.Heating valueThermal powerl/sNm3/m3 wateroCMJ/Nm3MWtep/hCaciulata9,42,4709632,00,7430,064Cozia23,01,9859230,51,3920,120Calimanesti18,02,6459231,01,4760,127TOTAL50,42,311*92,7*30,9*3,6110,311

The principle of gas engine cogeneration1-Cold water inlet; 2-Oil cooler; 3-Gas admission; 4-Four stroke gas engine; 5-Catalytic converter; 6-Exhaust gases heat exchanger; 7-Hot water boiler

Separated and combined production of electricity and thermal power

A) Steam turbine power plant ElectricityB) Boiler LossesC) Gas engine cogeneration unit Thermal power

Scheme of a cogeneration plant using gas engines

A) Heat accumulator Natural gas B) Boiler Electricity for public grid C) Gas engine cogeneration unit Thermal supply line T) Thermal consumer Thermal return line

The energy balance of a gas engine cogeneration unit

Combustible gases - Exhaust gas heat exchanger Electrical energy - Engine jacket heat exchanger Thermal energy (supply) - Oil heat exchanger Thermal energy (return) - Mixture intercooler

The necessary thermal power.

The mean thermal power for one year.

ConclusionsThe geothermal waters around the localities Climneti - Cciulata Cozia represent an important energy potential, due to both their temperature and to their composition (a high content of combustible gases, especially methane).The presence of these gases leads to the idea of their use as primary energy for the supply of a gas engines cogeneration unit, equipped with two engines which provide 700 kW electrical power each. The cogeneration unit is able to fully ensure the total thermal energy need in the considered area, both for heating and for domestic hot water preparation.The use of this cogeneration unit represents an important benefit from the economic and environmental point of view (an important economy of about 445000 kg liquid fuel/year).

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