Combustion Technology & Applications and Optimization of Combustion PDF

Lecture No. 4 Combustion Technology & Applications and Optimization of Combustion Dr. Mohammed Said Farag  Combustion Technology & Applications and Optimization of Combustion  Carbon dioxide nitrous oxide Combustion Methane Systems water vapor Chlorofluorocarbons (CFCs...

Lecture No. 4 Combustion Technology & Applications and Optimization of Combustion Dr. Mohammed Said Farag  Combustion Technology & Applications and Optimization of Combustion  Carbon dioxide nitrous oxide Combustion Methane Systems water vapor Chlorofluorocarbons (CFCs)  Petrol Engine nitrous oxide Combustion Methane Systems water vapor Chlorofluorocarbons (CFCs)  Petrol Engine Diesel Engine Combustion Methane Systems water vapor Chlorofluorocarbons (CFCs)  Petrol Engine Diesel Engine Combustion Gas Turbine Systems water vapor Chlorofluorocarbons (CFCs)  Petrol Engine Diesel Engine Combustion Gas Turbine Systems Furnaces Chlorofluorocarbons (CFCs)  Petrol Engine Diesel Engine Combustion Gas Turbine Systems Furnaces Boilers (Water Tube – Fire Tube)  Petrol Engine 4 Stroke 2 Stroke This series shows a cut-away diagrams of a Two-stroke petrol engine. This engine design is the simpler mechanically of two and four stroke as it minimize the number of moving parts which must be kept in sync. The description "two stroke" comes from the fact that the engine fires (burns fuel) on every upward stroke (travel of the piston from bottom of the cylinder to the top), thus there are two strokes for every ignition of fuel, and upward and a downward stroke. The first stroke moves from bottom to top, where compressed air and fuel ignite and begin the second stroke where the piston is forced back downwards by the explosive force of the fuel igniting. Gasoline engine, any of a class of internal-combustion engines that generate power by burning a volatile liquid fuel (gasoline or a gasoline mixture such as ethanol) with ignition initiated by an electric spark. Gasoline engines can be built to meet the requirements of practically any conceivable power-plant application, the most important being passenger automobiles, small trucks and buses, general aviation aircraft, outboard and small inboard marine units, moderate-sized stationary pumping, lighting plants, machine tools, and power tools. Four-stroke gasoline engines power the vast majority of automobiles, light trucks, medium-to-large motorcycles, and lawn mowers. Two-stroke gasoline engines are less common, but they are used for small outboard marine engines and in many handheld landscaping tools such as chain saws, hedge trimmers, and leaf blowers.  Spark ignition engine (petrol engine) How fuel handled fuel is used in a mist form. Carburetor atomizes gasoline creating a mixture of gasoline and air. Using electric spark to ignite the mixture in a combustion chamber to get the power in power stroke. Note: About 18:25% of the fuel burned is converted to mechanical energy.  The combustion system must be: 1- free from knock. 2- give certain ignition by spark. 3- reduce heat transfer. 4-burn fuel completely under all conditions.  Diesel Engine The diesel engine, named after the German engineer Rudolf Diesel, is an internal combustion engine in which ignition of the fuel is caused by the elevated temperature of the air in the cylinder due to mechanical compression; thus, the diesel engine is called a compression-ignition engine (CI engine) 4 Stroke 2 Stroke The diesel engine is defined as a machine which can convert energy in fuel to mechanical energy or motion. Diesel engine is a type of internal combustion engine or a compression ignition engine. Diesel engine consumes fuel to generate mechanical energy by exerting a torque to drive machinery that generates compressed gas. Fuel is injected into the combustion chambers through fuel injector nozzles with an oxidizer usually atmospheric air in each chamber under high pressure so that it reaches a very high temperature to burn the fuel and thus the phenomenon of combustion of fuel occurs. The fuel is ignited inside the engine by heat of compression with a separate source of ignition energy (such as a spark plug). The expansion of the high temperature and high pressure gases by the combustion will generate a mechanical force or energy to move the components of the engine such as the pistons, turbine blades or nozzle.  Compressed ignition engines (diesel engine) How fuel handled Fuel is used in a mist form. Injector injects fuel in a combustion chamber between compression and power strokes. Air is entering in a suction stroke. Compressing the mixture in compression stroke causes the ignition.  The combustion system must be : 1- provide smooth ignition. 2- use all available oxygen. 3- reduce heat transfer. 4- reduce pumping power. 5- emit no smoke. Gas Turbine A gas turbine or gas turbine engine is a type of continuous flow internal combustion engine. The main parts common to all gas turbine engines form the power-producing part (known as the gas generator or core) and are, in the direction of flow: a rotating gas compressor a combustor a compressor-driving turbine. Additional components have to be added to the gas generator to suit its application. Common to all is an air inlet but with different configurations to suit the requirements of marine use, land use or flight at speeds varying from stationary to supersonic. A propelling nozzle is added to produce thrust for flight. An extra turbine is added to drive a propeller (turboprop) or ducted fan (turbofan) to reduce fuel consumption (by increasing propulsive efficiency) at subsonic flight speeds. An extra turbine is also required to drive a helicopter rotor or land-vehicle transmission (turboshaft), marine propeller or electrical generator (power turbine). Greater thrust-to-weight ratio for flight is achieved with the addition of an after burner.  Gas turbine engine How fuel handled The fuel used is natural gas or distillate oil. The continuous feed of fuel and compressed air is ignited in the combustion chamber with continuous flame. The hot exhaust gases is tracked to the turbine blades to give the power.  The combustion system must be : 1- burn fuel completely. 2- cause little pressure drop. 3- produce gases at nearly uniform temp. 4-occupy small volume. 5- maintain stable combustion over wide range of pressures  The Industrial Furnace Furnaces form a major part of industrial heat treatment equipment and are used in metallurgical, engineering and industrial manufacturing applications. Glass, steel, iron, aluminum, plastics, textiles, die casting and foundry are just some of the industries which use industrial furnaces, ovens and incinerators. Furnaces may be classified by type of fuel; gas-fired (e.g., natural gas, largely methane, CH4), liquid- fired (e.g., fuel oil), or solid-fired (e.g., coal or wood). In typical furnace designs there is a combustion chamber, either enclosed or open to the air, in which fuel combines with the oxygen, O2, in air to form combustion products (largely carbon dioxide, CO2, and water, H2O) and to release heat. The heat can be transferred to a working fluid (e.g., air, water, or steam), which distributes it as required or expands (e.g., against a piston) to produce work. In steam engines, the heat from the furnace is transferred to a boiler in which water is converted into steam, the working fluid. There are many applications of combustion (e.g., in the steel industry and in welding) in which a working fluid is not employed: Heat released by combustion is applied directly to the object that is to be heated. Design of the combustion chamber is a central aspect of furnace design. Objectives are to obtain efficient and clean combustion and efficient and trouble-free heat transfer. Typically, fuel is metered into the combustion chamber where it meets air entrained by forced or natural convection. In gas- fired furnaces, fuel jets at the periphery of the chamber admit the fuel, possibly premixed with air, in flow patterns (often involving swirl) that are designed to achieve efficient combustion. In oil-fired furnaces, atomization of the liquid by the fuel injector (atomizer) and liquid-jet penetration are critical aspects in producing fine droplets properly distributed in air. Types of solid-fired furnaces may be listed as fixed-bed (in which the solid fuel is supported on a grate as it burns), fluidized-bed (in which gas flow through the bed of fuel agitates the solid elements of the bed to give them a fluid- like behavior), and pulverized-fuel (in which finely ground solid fuel is transported by a gas stream and injected in much the same way as the fuels of gas-fired furnaces). Coal–oil or coal–water slurries (solid suspensions in liquids) transport coal as a liquid to be burned in furnaces of liquid- fired design. Thus coal, the world's most plentiful fuel, can be used in furnaces of all three basic types.  Furnaces How fuel handled fuel is metered into the combustion chamber where it meets air entrained by forced or natural convection. In gas-fired furnaces, fuel jets at the periphery of the chamber admit the fuel, possibly premixed with air, in flow patterns (often involving swirl) that are designed to achieve efficient combustion. The flame in the industrial furnace must provide : 1- specified distribution of radiant and convective heat transfer. 2- complete combustion. 3- freedom from noise and oscillation. 4- insensitivity to fuel changes.  Boilers A boiler is a closed vessel in which fluid (generally water) is heated. The fluid does not necessarily boil. The heated or vaporized fluid exits the boiler for use in various processes or heating applications, including water heating, central heating, boiler-based power generation, cooking, and sanitation. Fire Tube Boiler Water Tube Boiler  Fire Tube Boiler A fire-tube boiler is a type of boiler invented in 1828 by Mark Seguin, in which hot gases pass from a fire through one or more tubes running through a sealed container of water. The heat of the gases is transferred through the walls of the tubes by thermal conduction, heating the water and ultimately creating steam. A fire-tube boiler is a type of boiler in which the water or other fluid to be heated flows through tubes that are surrounded by fire. This is in contrast to a water tube boiler, in which the fire flows through tubes that are surrounded by water. Fire-tube boilers are typically used for smaller applications, such as heating homes or businesses, while water-tube boilers are used for larger applications, such as generating steam for power plants. There are two main types of fire tube boilers: horizontal fire-tube boilers and vertical fire tube boilers. Horizontal fire tube boilers are the most common type and are typically used for residential and commercial applications. Vertical fire-tube boilers are less common but are used in some industrial applications. Fire Tube boiler is the simplest form of the internal furnace, a vertical fire tube boiler. Fire tube boilers are a portable boiler and it requires a small floor space. Fire Tube boilers are known for their compact design and efficient heat transfer capabilities, making them an ideal choice for applications where space is limited. Additionally, their portable nature allows for easy installation and relocation, making them versatile in various settings. The working principle of a fire tube boiler is relatively straightforward. In a fire tube boiler, hot gases pass through a series of tubes that are immersed in water within the boiler shell. The heat from the gases is transferred through the walls of the tubes to the water, creating steam. Here are the key steps in the working principle: Fuel Combustion: The boiler is fueled, typically with coal, wood, or oil. The fuel undergoes combustion in the furnace, generating hot gases. Gases Flow Through Tubes: The hot gases produced during combustion travel through the tubes that are submerged in water. Heat Transfer: As the hot gases move through the tubes, heat is transferred from the gases to the water surrounding the tubes. This heat transfer raises the temperature of the water and converts it into steam. Steam Generation: The steam produced is collected in the upper part of the boiler, ready for use in various applications such as power generation or heating. Exhaust: After transferring heat to the water, the cooled gases exit the boiler through the chimney or stack. Providing an efficient and reliable design, the fire tube or shell boiler has been used extensively for the generation of energy in a wide range of industrial processes and heating applications. The shell boiler is the main thermal energy generator in medium sized steam intensive industries and is one of the primary items for technical evaluation when seeking to optimize efficiency in either existing plants, or the replacement of obsolete equipment and the introduction of new plant  Fire Tube Boiler How fuel handled Gas boilers first mix fuel (usually natural gas, liquefied gas, etc.) with air through a burner. In the combustion chamber, the mixed gas is ignited to form a high-temperature flame. This combustion process causes the chemical energy within the fuel to be released as heat energy. Fuel types and properties Main requirements from the combustion system of fire tube boiler : 1- specified maximum flame length. 2- axis-symmetric flame. 3- nearly uniform heat flux. 4- high heat transfer by radiation 5- complete combustion. 6-freedom from oscillation. 7- low swirl of combustion air.  Water Tube Boiler A water tube boiler is a type of boiler that uses water that is circulated through tubes that are surrounded by hot combustion gases. The water is heated by the combustion gases and turns into steam, which can be used to power turbines or other machinery. A water tube boiler is a type of boiler in which water circulates through tubes that are heated externally by the fire. Fuel is burned inside the furnace, creating hot gas which boils water in the steam-generating tubes. The heated water/steam mixture then rises into the steam drum. Here, saturated steam is drawn off the top of the drum. Water tube boilers are typically larger and can handle higher pressure and temperatures than fire tube boilers. They also have a higher thermal efficiency, which means they can convert a larger amount of fuel into useful energy. Water tube boilers are used in thermal power plant, industrial facilities, and ships. Water tube boilers are a type of boiler that uses water circulating through a network of tubes to generate steam or hot water. The water is heated by combustion gases that flow around the tubes, in contrast to fire tube boilers, where the water surrounds the hot gases. Water tube boilers are more efficient, faster, and can handle higher pressures than fire tube boilers. They are commonly used in industries such as power generation, chemical processing, and petrochemicals. Water tube boilers are commonly used in industries such as power generation, chemical processing, and petrochemicals, where high-pressure steam is required for various processes. The construction of a water tube boiler typically involves a steam drum at the top, where water and steam are separated. Water enters the boiler from the bottom and is heated as it flows through the tubes. The heated water rises and collects in the steam drum, where steam is separated and can be drawn off for various applications. The remaining water, which hasn’t turned into steam, continues its journey through the tubes, getting reheated and eventually reaching the steam drum. Water tube boilers are a versatile and efficient solution for industrial steam and hot water generation. They are capable of handling high pressures and temperatures, making them suitable for a wide range of applications. Water tube boilers are commonly used for high-pressure applications, such as in power plants and industrial processes. These boilers differ from traditional fire-tube boilers, where hot gases from the combustion process flow through tubes carrying water. In water tube boilers, water flows through the tubes while hot combustion gases flow over them. Here’s how they work: Water is pumped into the boiler from an external source, such as a tank or a water treatment system. The water flows through a series of tubes, which form the walls of the boiler’s furnace. Fuel, such as natural gas, coal, or oil, is burned, and the resulting hot gases flow over the tubes. Heat from the combustion gases is transferred to the water inside the tubes, causing it to heat up and generate steam. The steam rises to the top of the boiler and is collected in a steam drum, where it is separated from any remaining water. The dry steam is then piped out of the drum and used for energy generation or other processes. Water tube boilers offer several advantages over fire-tube boilers, including higher efficiency, faster steam generation, and the ability to handle higher pressures and temperatures. However, they are typically more complex and expensive to manufacture and maintain. Water Tube Boiler Working Principle Fuel combustion: The first step is to burn fuel in the furnace. The fuel can be any type of combustible material, such as coal, oil, or natural gas. The combustion process creates hot gases, which are the source of heat for the boiler. Water heating: The hot gases from the furnace flow through the water tubes, heating the water inside the tubes. The water tubes are made of a material that can withstand high temperatures, such as steel or copper. The water is heated until it reaches the boiling point, at which point it turns into steam. Steam separation: The steam rises to the steam drum, where it is separated from the water. The steam drum is a large vessel that is located at the top of the boiler. The steam is drawn off from the steam drum for use in various applications. Water circulation: The remaining water flows back down to the furnace, where it is reheated and the process repeats. The water circulation process is driven by the difference in density between hot water and cold water. Hot water is less dense than cold water, so it rises to the top of the boiler. This creates a circulation loop, with the hot water rising to the top and the cold water flowing down to the bottom. Water tube boilers are a very efficient way to generate steam or hot water. They are also capable of handling high pressures and temperatures, making them suitable for a wide range of applications.  Water Tube Boiler How fuel handled The water flows through a series of tubes, which form the walls of the boiler's furnace. Fuel, such as natural gas, coal, or oil, is burned, and the resulting hot gases flow over the tubes. Heat from the combustion gases is transferred to the water inside the tubes, causing it to heat up and generate steam. Fuel types and properties Main requirements from the combustion system of water tube boiler : 1- specified max. flam length. 2- nearly uniform heat flux in water walls. 3- high radiation flame 4-complete combustion Agricultural activities, such as the use of synthetic fertilizers and manure management Industrial processes, including the production of nitric acid Combustion and adipic acid Optimization Combustion of fossil fuels, especially in vehicles and power plants  Meaning of optimize combustion. Industrial processes, including the production of nitric acid Combustion and adipic acid Optimization Combustion of fossil fuels, especially in vehicles and power plants  Meaning of optimize combustion. Combustion Why we optimize Optimization combustion. Combustion of fossil fuels, especially in vehicles and power plants  Meaning of optimize combustion. Combustion Why we optimize Optimization combustion. How we optimize combustion.  Meaning of optimize combustion Increasing thermal efficiency of combustion as possible as we can with decreasing fuel consumption. Note: 1- steam power plant thermal efficiency From 1992 to 2007 is 42:47% & Hope in 2020 reaches 50% 2- gas turbine power plant thermal efficiency For existing plants 25:40% & For new plants 36:40% 3- combined heat and power cycle efficiency For steam turbines Modern large turbine eff. 46:47% &Small units with CHP (Combined Heat and Power) eff. 30:42% 4- For gas turbines Allows efficiency to be up to 90%  Why Optimizing Combustion Demand > Production Decrease fuel consumption. Recovering to heat sources. Finding the renewable sources of energy.