This is a blogg for operation/safety/project aspects of Coking industry and we do not get into the marketing aspects of petcoke here.
If you already know which refinery you want to buy from – then look up the contact for that company in the operations group and ask they if they can put you in touch with their petcoke marketing group. One of the reasons that petcoke marketers are hard to find is that they handle other products as well (fuel oil or lubes or asphalt) or that they use a reseller or marketer to sell the petcoke.
You should subscribe to one of the reporting agencies that follow the petcoke market who do monthly surveys of price/sales/production and ect for that market. Argus Petroleum Coke, Jacobs/Pace Quarterly coke report/CemReview Petcoke Report/Energy Publishing Petcoke Report/CRU Carbon Monitor and many others of this nature. The cost for their reports runs between $USD 5,000 to $10,000/year.
Again this is not the site to find market information and we do not want to clogg up the news site with market type information that is of little interest (and usually of less value) than info they already have from their marketing group when they need it.