Adding gas from biomass to the gas grid - SGC

Measurement methodDetection tubes for hydrogensulphide, mercaptans, ammonia,halogenated hydrocarbonSulphurous componentsGC analysisHalogen containing componentsGC analysisSiloxanesGC MSD analysisOdorosity.OrgananolepticUnit TypicalaccuracyRemarksmg/m 3 50% Detection tubes can be appliedfor the semi quantitativemeasurementmg/m 3 25% Detailed information at start upand in case of problemsmg/m 3 50% Detailed information at start upand in case of problemsnone qualitative Incidental in case of complaintsnone acceptable /not acceptableIncidental measurement incompletion to an adequateodorisation systemTable 30: Measurement methods for spot checksThe spot checks are mainly performed on components to be removed by a long lasting sorptionmass or catalyst bed. With detection tubes it is detected whether the sorption mass or catalyst bedis still active or not. GC analyses are performed to gain detailed information at start-up or at lastingproblems in the process.6.3.3 Energy measurement for billing purposesThree methodologies are used to obtain the comptable data on the energy flow for billing purposes:• Volume measurement in combined with fixed data on energy content of the gas.This is the method used at small gas flows. There is a fixed price for a volume of gas during thewhole payment period.• Volume measurement in combination with data on averaged energy values.This method is applied at larger gas flows with small fluctuations in the calorific value of the gas.• Volume measurement in combination with on-line measured energy values.This method is also applied at larger gas flows. Most gas production sites measure the maincomposition on-line, and thereby know the actual calorific value.Volume measurementTurbine gas meters (up to about 1000 m 3 /hour) perform most gas volume measurements. At largerflows accuracy becomes more important. On-line applying electronic pressure and temperaturesensors and an on-line data processor (above about 1000 m 3 /hour) perform corrections for pressureand temperature.At still larger flows and higher pressures also a correction for the compressibility is performed. Thiscompressibility is calculated from the expected gas composition. In most situations the additionalpage: 74