Render time adobe after effects

Hi

I am new to after effects recently. But recently I have done a few backdrops with simple particle effects such as snow on to of existing jpeg images (10mb). I rendered these out and the time was 40mins approx. More recently I have created another backdrop with twinkling light on tree and garland and also a fireplace with moving fire. All were done using particles. But when I go to render this, my estimated time is 14hrs. Please can someone advise me on this as I have about 10 of these to do and can't have render time of 140hrs altogether, I used both aftereffects and adobe media encoder both with similar results.

thanks