Title : Optimization of natural draught fired heater for fuel consumption saving in LPG gas plant at Zueitina Oil company
Abstract:
The furnace becomes the primary heat source for all industrial petroleumprocessing plants and refineries, supplying heat through the combustion of fuel and air. One of the most effective techniques for lowering fuel loss and maintaining steady refinery incomes, saving energy, and ultimately lowering overall fuel costs is the model-based furnace simulation. For analyzing thevariables influencing increasing daily fuel consumption, which records 13.5% of the feed quantities, a model-based simulation for an industrial scale natural air draught fired heater related to a Zueitina Oil Company-owned liquefied petroleum gas (LPG) production plant in Libya is carried out in this paper. Aspen Hysys V.11 is used to model both fired heaters. besides contributing to the effects of an excess air on furnace efficiency, this is especially used to evaluate the heat loss from the furnace stack through walls and flue gas, as well as the heat loss from the firebox to the surrounding medium. Additionally, this study seeks to determine if the plant's daily fuel consumption is influenced by operating circumstances, such as furnaces tube inlet flow rate and pressure, and whether these variables need to be adjusted to meet upstream process design parameters.
The results of the study demonstrate that a 20% reduction in both furnace passes flow will result in a 10% decrease in consumption of fuel. In the depropanizer furnace, the flue gas temperature reduced by 25%, and in the debutanizer furnace, it declined by almost 60%. That percentage represented heating losses from flue gasses. The ideal operating conditions of 20% excess air and 3.3% flue gas oxygen content delivered to the stack are used to accomplish this improvement. The flue gas temperature reduction has boosted the furnaces' efficiency by 40% to achieve 86.9% in the first furnace, 26F1, and by 15% in the second furnace 26F-5 to hit 67%.
As consequently, a noticeable decline in the consumption of fuel each day is noticed, measuring to almost 5% of the total plant feed, approximately 22.4 million dollars annually. The results of the study conclusively show the opportunity of drastically reducing maintenance and operating costs.
