Heat oil in Dutch oven. Stir in flour, a tablespoon at a time; cook, stirring, until flour begins to brown, 3 to 4 minutes.
Add onion, garlic, green pepper, celery, jalapeño; cook for 10 to 12 minutes, until celery is softened. Add tomatoes, red-pepper flakes, paprika, cayenne, pepper sauce, bouillon liquid and rice. Simmer, covered, for 20 minutes.
Add shrimp, scallops, salt and pepper; simmer until seafood is opaque, about 3 minutes.