ENERGY audit OF COMBUSTION SYSTEMS P M V Subbarao Professor Mechanical Engineering Department Detailing of Losses and Causes …..

Typical Layout of A Coal Fired Furnace For Adiabatic Furnace Hchimney Tgas pA = pfan.f Tatm B B A pB = pfan,s

Typical Layout of A Coal Fired Furnace For A Furnace generating Steam Hchimney Tgas pA = pfan.f pB = pfan,s Tatm B B A

Energy Potential of Post Combustion Gases Total Thermal Power of post combustion gases: Thermal Power of Chimney inlet gases: Total Thermal Power of post gases available for steam production: Rate of steam production:

Specific Enthalpy Increase due to Generate Superheated Steam 3 5 2s 2f 4 2 1 6 s

Sankey Diagram for A Coal Fired Furnace Heat gained by boiling water 40% Loss due to moisture in air. Loss due to moisture in fuel. Loss due to combustion generated moisture. Dry Exhaust Gas Losses ~ 4.5% Fuel Energy 100% Hot gas Heat gained by superheater & reheater 40% Heat gained by economizer 6% Heat gained by air preheater 6% Flue gas Heat loss from furnace surface. Unburned carbon losses. Incomplete combustion losses. Loss due to hot ash.

Air & Gas Path in A Coal Furnace

Distributed Air Supply Systems

Paths of Steam and Gas Drum Water walls Economizer

Thermal Structure of A Boiler Furnace DPNL SH Platen SHTR R H T LTSH Economiser APH ESP ID Fan drum Furnace BCW pump Bottom ash stack screen tubes

Dry Exhaust Gas Losses As gasses are leaving at temperature higher than ambient temperature. For 100 kg of fuel. QDEGL = S n fluegas Dhfluegas QDEGL = n CO2 DhCO2 + n CO DhCO + n O2 DhO2 + n N2 DhN2 + n SO2 DhSO2 kJ. For any gas per unit mass flow rate Approximate method: Total number of moles of dry exhaust gas nex.gas = P+R+T+U+V QDEGL = nex. Gas Cp,exgas (Tex.gas - Tatm) Cp.exgas = 30.6 kJ/kmol. K Typical value of DEGL ~ 4.5%

Unburned carbon losses. For 100 kg of fuel QUCL = nc * MC * Calorific Value of Carbon : kJ QUCL = nc * 12 * 33820 kJ. Incomplete combustion losses For 100 kg of fuel: QICL = nCO * MCO * CV of CO. kJ. QICL = nCO* 28 * 23717 kJ.

Loss due to moisture in Combustion air For 100 kg of fuel: QMCAL = e 4.76 (X+Y/2+Z-K/2) * 29.9 * w * Csteam * (Tg – Tamb) kJ Where w is absolute or specific humidity : kg of moisture per kg of dry air. Csteam is the specific heat of steam at constant pressure : 1.88 kJ/kg C. Tg is the temperature of exhaust gas.

Losses due to moisture in fuel & combustion generated moisture. For 100 kg of fuel: QML = ( M +9* Y) {2442 + Csteam * (Tg – Tamb) } kJ. M is the moisture content in the fuel, %. Y is the combustible hydrogen atoms in the fuel.

Loss due to hot ash or Slag For 100 kg of fuel QASL = A * Cp,ash * ∆Tash Where Cp.ash, is the specific heat of ash, 0.5 – 0.6 kJ/kg K. Tash is the temperature of the ash or slag. Tash = Varies from 300 to 800 oC

Heat loss from furnace surface Rate of Heat Loss due to Surface Radiation and Convection. QRCL = As ( hs) (Tsurface - Tamb) kW As = Total surface area, m2 hs = Surface heat transfer coefficient. For 100 kg of fuel: Rate of heat loss/fuel flow rate * 100

A Graphic Model for Radiation & Unaccounted Loss

Minimization of Energy Losses thru Control of Excess Air

Losses due to Fuel Quality Fuel Samples

Selection of Optimal air for Best Performance % of Excess Air

Selection of Optimal air for Eco-Friendliness

Learning of Impact of Excess Air

Holistic Combustion Optimization Method % of Excess Air

Methods to Apply the Machine Learning

Performance Analysis of Internal Combustion Systems

Sankey Diagram for Spark Ignition Reciprocating IC Engine for A A Ship

The Interesting News The world’s biggest engine is the Wärtsilä-Sulzer RTA96. It’s the largest internal combustion engine ever built by man. Wärtsilä-Sulzer RTA96-C is a 14-cylinder, turbocharged diesel engine that was specially designed to power the Emma Maersk which is owned by the Danish Maersk. Wärtsilä-Sulzer RTA96, the world’s biggest engine, has a weight of 2.3 million kilogrammes. If the weight of the average adult person is 70 kgs, this world’s biggest engine has a weight equivalent to the weight of 33,000 people.

Wärtsilä-Sulzer RTA96-C

Economies of Scale in Sea Transportation Maersk Lines have done the world proud by providing cheap sea transportation that is costing cents instead of a dollar per every kg weight. They are able to do this by using economies of scale in sea transportation. It is getting cheaper to ship goods from USA to China and from China to USA. It has now become cheaper to transport goods from China to a US port than to transport the same goods from a US port to the final destination inland of US by a truck.

Sankey Diagram for Spark Ignition Reciprocating IC Engine for A Car

Energy Losses in State of the Art Aircraft Engines