Mini Project PPT for engineers first.pdf
- 1. Analysis of Energy Conservation Measures in Industrial Furnace Guided by Dr. J. A. Goyal Nirmay Vijay Devrukhkar - B10 Ritesh Sarju Sharma - B48 Devesh Meghnath Sawant - B40 Aabha Rajeev Tembe - B65
- 2. Introduction ❖ What is Furnace? A Furnace is a combustion chamber containing the heating system and the material being heated, which is often referred to as the load. ➢ How a Central Gas Furnace Works 1. Simply put, a central gas heating system creates a cycle of warming cooler air. 2. Burning propane or natural gas generates heat in the furnace's burner. 3. The heat produced passes through a heat exchanger, making it hot. 4. Air from the home's ductwork is blown over the heat exchanger, warming the air. 5. The furnace's blower then forces the heated air into the supply ductwork, distributing it throughout the home.
- 3. Motivation 1. The growing industrialization and rapid technological developments result in huge amounts of energy consumptions. Due to the increase in energy usage and the raised consumptions of fossil fuels, we witness a high level of released carbon dioxide (CO2) released to the atmosphere. 2. To alleviate a cause greenhouse effect and climate change, we are and requires an efficient use of energy resources. 3. Numerous furnaces and boilers are extensively used in industrial and commercial facilities to generate thermal energy so that small improvements of the furnace thermal efficiency will amount to tremendous reduction of energy consumption and green gas emission. 4. Numbers of researchers have been done research on reduced Energy consumption or Energy Saving in Furnace and also some researches are needed to improve furnace performance and reduced fuel consumption. 5. The main goal here should be To evaluate the potential for energy savings and increase the energy efficiency in industrial furnaces.
- 4. Problem Statement 1. Incomplete combustion of the fuel 2. Sensible heat of the fuel Gas 3. Radiation and convection through furnace walls 4. Latent heat of condensation of water vapor in the fuel
- 5. Objective 1. The overall objective of the energy conservation for furnaces is to guide the management and operators in furnaces to manage energy consumption by standardizing the energy performance values of various energy consuming equipment and systems deployed for manufacturing process. 2. One of the important components under the overarching framework of the energy conservation guidelines is benchmarking of standard energy performance values and a procedure for establishing target energy performance values for major energy consuming equipment such as boiler, furnace, thermic fluid heater, waste heat recovery equipment, motor, etc. 3. The objective of this document is to provide energy conservation guidelines to furnaces
- 6. Methodology Heat Transfer in Furnaces • Radiation from the flame, hot combustion products and the furnace walls and roof. • Convection due to the movement of hot gases over the stock surface.
- 7. Methodology The various losses that occur in the fuel fired furnace are: 1. Heat lost through exhaust gases either as sensible heat, latent heat or as incomplete 2. combustion 3. Heat loss through furnace walls and hearth 4. Heat loss to the surroundings by radiation and convection from the outer surface of the walls 5. Heat loss through gases leaking through cracks, openings and doors.
- 8. Methodology Characteristics of an Efficient Furnace • Determination of the quantity of heat to be imparted to the material or change. • Liberation of sufficient heat within the furnace to heat the stock and overcome all heat loses. • Transfer of available part of that heat from the furnace gases to the surface of the heating stock. • Equalization of the temperature within the stock. • Reduction of heat loses from the furnace to the minimum possible extent.
- 9. Methodology Characteristics of an Efficient Furnace • Determination of the quantity of heat to be imparted to the material or change. • Liberation of sufficient heat within the furnace to heat the stock and overcome all heat loses. • Transfer of available part of that heat from the furnace gases to the surface of the heating stock. • Equalization of the temperature within the stock. • Reduction of heat loses from the furnace to the minimum possible extent.
- 10. Methodology Methods for Testing Furnace Efficiency • Direct Method Testing • Indirect Method Testing
- 11. Formulae 1. Furnace Efficiency, η = Heat in stock material (KCals) Heat in fuel or Electricity(KCals) × 100 2. Specific Energy Consumption = Quantity of fuel or energy consumed Quantity of material processed 3. The quantity of heat to be imparted, 𝑄 = 𝑚 × 𝐶𝑝 × (𝑡2 − 𝑡1) 4. Total heat loss through radiation = Black body radiation × area of opening × factor of radiation × emissivity
- 12. Efficiency Measures 1. Complete combustion with minimum excess air 2. Correct heat distribution 3. Operating at the desired temperature 4. Reducing heat losses from furnace openings 5. Maintaining correct amount of furnace draught 6. Optimum capacity utilization 7. Waste heat recovery from the flue gases 8. Minimum refractory losses 9. Use of Ceramic Coatings
- 13. Efficiency Measures Complete combustion with minimum excess air: The amount of heat loss is directly proportional to the amount of excess air. If we control air infiltration, maintain the pressure of combustion air, fuel quality, and excess air monitoring we can obtain complete combustion with a minimum amount of air. 0 10 20 30 40 50 60 70 80 1 1.2 1.4 1.6 1.8 2 1000℃ 800℃ 600℃ 400℃ 300℃ 200℃ Air ratio Exhaust gas loss (%) Relation Between Air Ratio and Exhaust Gas Loss
- 14. Efficiency Measures Proper heat distribution: By using a minimum fuel firing rate, a uniform heat should be distributed throughout the furnace in a given time. There are some things to be taken care of while using burners. For example, the flames of different burners in the furnace should stay clear of each other. If they intersect, inefficient combustion would occur. If the flames impinge on refractories, the incomplete combustion products can settle and react with the refractory constituents at high flame temperatures.
- 15. Efficiency Measures Maintaining Optimum Operating Temperature of Furnace: It is crucial to operate a furnace at an optimum temperature. Heat loss, excessive oxidation, de-carbonization as well as over- stressing of the refractories are some of the errors caused when the temperature is higher than optimum temperature. OPERATING TEMPERATURE OF VARIOUS FURNACES Slab Reheating furnaces 1200℃ Rolling Mill furnaces 1200℃ Bar furnace for Sheet Mill 800℃ Bogey type annealing furnaces 650℃ - 750℃
- 16. Efficiency Measures Prevention of Heat Loss through Openings: Heat loss through openings consists of the heat loss by direct radiation through openings and the heat loss caused by combustion gas that leaks through openings. Control of furnace draft: The air-fuel ratio control is affected by the negative pressures existing in the furnace, the air filtration occurring through the cracks and openings. Neglecting furnaces pressures can lead to non-uniform metal temperatures affecting operations like forging rolling etc. Hence, increasing the fuel consumption. To avoid this issue a slight positive pressure is maintained in the furnace.
- 17. Efficiency Measures Optimum Capacity Utilization: One of the major factors affecting efficiency is loading. In a furnace at a particular loading, there is perfect thermal efficiency. If there is a small amount of loading in the furnace the efficiency is low. The loading of the charge on the furnace hearth should be arranged so that. It receives the maximum amount of radiation from the hot surfaces of the heating chambers and the flames produced. The hot gases have efficiently circulated the heat receiving surfaces. If seen from the economic point of view, work quality the materials comprising the load should only remain in the furnace for the minimum time to obtain the required physical and metallurgical requirements. Optimum utilization of the furnace can be planned at the design stage. Correct furnaces for the jobs should be selected considering whether continuous or batch type furnaces would be more suitable.
- 18. Efficiency Measures Waste Heat Recovery from Furnace Flue Gases: The products of combustion leave the furnace at a temperature higher than the stock temperature. Waste heat recovery should be considered after all other energy conservation measures have been taken. Minimizing the generation of waste heat should be the primary objective. The sensible heat in flue gases can be generally recovered by the following methods. ➢Charge (stock) preheating,(when raw materials are preheated by exhaust gases before being placed in a heating furnace, the amount of fuel necessary to heat them in the furnace is reduced) ➢Preheating of combustion air (The energy contained in the exhaust gases can be recycled by using it to pre-heat the combustion air. A variety of equipment is available; external recuperators are common, but other techniques are now available such as self-recuperative burners) ➢Utilizing waste heat for other process (to generate steam or hot water by a waste heat boiler)
- 19. Efficiency Measures Minimizing Wall Losses: About 30-40% of the fuel input to the furnace generally goes to make up for heat losses in intermittent or continuous furnaces. The appropriate choice of refractory and insulation materials goes a long way in achieving fairly high fuel savings in industrial furnaces. The heat losses from furnace walls affect the fuel economy considerably. The extent of wall losses depends on: ➢Emissivity of wall ➢Thermal conductivity of refractories ➢Wall thickness ➢Whether furnace is operated continuously or intermittently
- 20. Efficiency Measures Use of Ceramic Coatings: Ceramic coatings in furnace chamber promote rapid and efficient transfer of heat, uniform heating and extended life of refractories. The emissivity of conventional refractories decreases with increase in temperature whereas for ceramic coatings it increases. This outstanding property has been exploited for use in hot face insulation. Ceramic coatings are high emissivity coatings which when applied has a long life at temperatures up to 1350℃. The coatings fall into two general categories-those used for coating metal substrates, and those used for coating refractory substrates. The coatings are non-toxic, non- flammable and water based.
- 21. Conclusion
- 22. THANK YOU!