New Orleans Style Red Beans and Rice

Name: New Orleans Style Red Beans and Rice
Ingredients: 1 pound red beans, (rinsed and sorted); 2 tablespoons olive oil; 1 cup onion, (chopped); 3 celery stalks, (chopped); 3/4 cup bell pepper, (chopped); 3 cloves garlic, (minced); 1 pound pork sausage, (sliced into 1/4-inch pieces); 2 leaves bay; 1/2 teaspoon salt; 1/4 teaspoon black pepper; pinch of cayenne pepper; 1/2 teaspoon dried thyme; 8 cups water; 1/2 tablespoons butter