Mini Pottery kiln with NEMA 5-20 plug that requires 120volts, 16amps, 1920 watts, and 20amp breaker
Using an "adapter" is out of the question.


Get an outlet tester and make sure all the receptacles work.  If any receptacles don't work, make an effort to repair them, or positvely determine they are not part of a 20A circuit.  
Turn off all 20A breakers.  
Go back around and find which receptacles have lost power just now.    Mark them "20???". 
Inspect every single one of them to assure that all the wires are #12, not #14 size.  #14 will cheerfully fit in a "backstab" hole of a receptacle labled "#14 wire only".  #12 will fit very tightly or not at all.   If you can get a specimen of each, you can just hold them up to compare. 
If all the wires on all the "20???" outlets is #12 wire, feel free to change any of them to NEMA 5-20 receptacles.  Remember to check for any broken tabs on the old receptacle.  


Feel free to limit this exercise to just one breaker if you know the other won't have plugs where you need them.