Completed my first blacksmithing job in approximately 30 years and made a number 8 branding iron but I had a problem getting the coke to burn any ideas on solving this problem 

Coke needs a  constant airflow to keep it going. If you are using a hand crank blower, coke is not suggested.

Thanks 

Get a Thrall to crank the blower, problem solved.

It is obvious that IF&C has not had to deal with a bellows thrall before.  Problems sourcing good minions date back millenia! Just when you have them trained their mothers want them to come home---or they discover that humans come in two types or they get a smartphone, sigh.

Break it into smaller pieces, acorn max. The greater surface area will allow it to burn faster and will consume the oxy from the blast lower to the air grate. This means more heat in the same volume, hotter, and no oxy means your stock wont scale up in the fire.

Make sure the thralls have plenty of cookies and root beer.

Frosty The Lucky.

I agree with Frosty, break it up smaller. The coke you have there would be OK if your forge was twice the size and you could mound it up more to get more of a coke oven effect, but you would need to be working big stock to justify a fire that big.

Andrew