If you haven't already cooked the beans, do so.
Heat 12 tablespoons / scant ⅔ cup of the olive oil in a large pot over medium-high heat.
When the oil is hot, add the celery, and stir until coated with olive oil. Cook for ten minutes, stirring often.
Add ⅔ of the scallions, the garlic, caraway, and a couple big pinches of salt. Cook for another 10 - 15 minutes, or until everything softens and begins to caramelize a bit.
Add the tomatoes and 2 teaspoons of the celery salt and cook for another few minutes.
Add the beans along with 5 ½ cups liquid (I typically do 2 cups bean liquid/broth + 3 ½ cups water), and remaining 4 tablespoons of olive oil.
Bring to a simmer, taste, and season with more salt or celery salt if needed.
Let sit for a couple minutes and serve each bowl topped with a spoonful of chopped olives and a squeeze of lemon.
You might also like to serve the soup sprinkled with the remaining scallions/spring onions.