Leviticus 1:13 (ESV)
13 but the entrails and the legs he shall wash with water. And the priest shall offer all of it and burn it on the altar; it is a burnt offering, a food offering with a pleasing aroma to the LORD.
The verb “to burn” (qṭr) literally means “to turn into smoke.” This is a graphic image which directs the worshipper’s attention to the smoke of the sacrifice ascending from the altar to the Lord.
9 but its entrails and its legs he shall wash with water. And the priest shall burn all of it on the altar, as a burnt offering, a food offering with a pleasing aroma to the LORD.