Fire Effects:To create the flame from Gas cylinder I used the plug-in FumeFX because this plug-in can make the realistic looking flame and very easy to do the settings.
Rendering
The importance of render settings are as follows:-
Global switches: Please uncheck the Default light.
Image Sample: Choose Type Adaptive subdivision and Antialiasing. Select Catmull-Rom which makes the image sharper.
Indirect illumination: Choose Irradiance map and Quasi-Monte Carlo subsequently.
Irradiance map: Choose Current present preset: High, HSph=80, Intrep=60 (If you fill high numeric then you will loose long time in rendering)
Monte Carlo Gl: Choose Subdivs=25 or more than that.
Environment: Choose light blue, nearly yellow for making sunlight.
rQMC Sampler: Reduce numeric of noise for reduce black point.
Color mapping: Choose Linear Multiply for make the colorful, setting Dark=0.9 and Bright =1.2 that make the brightness and darkness clear.