Heat the olive oil in a saucepan over medium heat until it shimmers. Add the onions and celery, and cook until soft.
Add the lentils and all the other ingredients in the first section of the list, plus enough water to cover the lentils by about a half-inch. Lower the heat to a simmer and cook for one hour. Stir now and then during the cooking. The lentils are ready when they can be squashed between thumb and forefinger but are still a little firm. Remove from heat and allow to cool.
Heat a heavy skillet over high heat. Dust the scallops with the Creole seasoning and salt. Dip them into the melted butter, and sear them on each side for one or two minutes, depending on size. They should bulge noticeably when they're ready. Scallops don't need a lot of cooking, so if you think they may be done, they probably are.
Spoon the scallops on warm plates in a line across the plate, Set four to six scallops, depending on size, onto the lentils. Serve with a wedge of lemon.