hskk:
As a Chemical Engineer you should easily be able to calculate the resultant pressure of the Methane cylinder contents in order to find the appropriate match with available compressed gas cylinders. To find out the standarization of available compressed gas cylinders and the associated valves and relief devices, go to the CGA (Compressed Gas Association) website and order/buy their authoritative book on compressed gases titled: "Handbook of Compressed Gases". In it, you'll quickly be oriented with the criteria and the subject matter involved in compressing and bottling Methane and other gases.
Good Luck.