In a large saucepan, heat the olive oil over medium heat. Add the bacon and cook, stirring occasionally, until rendered but not crisp, about 5 minutes. Add the onion, carrot, celery, and a generous pinch of salt. Cook, stirring occasionally, until the vegetables are softened, about 7 minutes. Add the farro, tomatoes, chipotles, and adobo sauce. Cook, stirring, until bubbling, about 2 minutes. Stir in the broth and bring to a boil over high heat, then cover partially and simmer over medium heat, stirring occasionally, until the farro is tender, about 20 minutes.