Task 1 Gas Dispersion calculation In a ground-level natural gas transportation line, under an operating pressure of 120 bar and an ambient temperature of 20C, one release occurred to a 1/2 in nozzle connecting to a flow transmitter (assuming a full-nozzle release to the atmosphere). The wind speed is 5m/s (Atmospheric stability C). Assuming the dispersion occurred in rural conditions, the effect of terrain and obstacles is ignored. Please determine: (NOTE: Students are encouraged to use Excel tool to conduct calculation and plotting during workshop. However, Excel is not allowed during exams, and only approved calculators are allowed.) (1) Release rate of methane at the nozzle (Methane specific heat: Cp=2.232kJ/kgK,CV=1.709kg/kgK, assuming discharge is from a smooth hole). (Solution: 2.1kg/s ) (2) Plot mean concentration against centreline dispersion distance on the ground. (3) At what distance in the centreline dispersion, it reaches a lower flammability limit (LFL) 5%(V/v) ? (Solution: 2122m) (4) At a downwindi distance 15m ground level, please calculate and plot the gas concentration at the crosswind direction