R. T. Morrison, R. N. Boyd: Chemia organiczna, tom 2 (rozdz. Tłuszcze) R. Bogoczek, E. Kociołek-Balawejder: Technologia chemiczna organiczna, rozdz. R. T. Morrison, R. N. Boyd: Chemia organiczna, tom 2 (rozdz. R. Bogoczek, E. Kociołek-Balawejder: Technologia chemiczna organiczna, rozdz. 2,. WAE. Romuald Bogoczek () ObituaryPrzemysl Chemiczny . Technologia chemiczna organiczna – wybrane zagadnieniaWydawnictwo.
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Some basic information about the module
Grzegorz Litwinienko roomconsultations: Chemia organiczna, tom 2 rozdz. Podstawy technologii bgooczek, rozdz. Technologia chemiczna organiczna, rozdz. Spalanie i paliwa praca zbiorowa pod red. Student are obliged to search information on the presented subjects from additional sources physical chemistry and thermochemistry textbooks from the library, internet sources etc.
Combustible materials flammable substances.
Fuels definition and classification. Combustion processes, chain reactions, heat of combustion and calorific value, explosions, explosion limit, sparkignition engine, compression-ignition engine Diesel engine, diesel. Cetane Number, Octane Number. Basic concepts and definitions of thermodynamics and thermochemistry: Heat transfer and mechanisms of heat exchange heat conduction, convection, thermal radiation. Knowledge on the procedures of analysis of biofuels and analysis of combustion products, described in this manual.
Fuels are a source of energy in the sense that chemical energy is orrganiczna into heat energy as a result of chemical processes. Based on the criterion of fuel origin, fuels can be divided into two main groups: Taking into account other criteria we can distinguish, depending on the state of matter: Depending on the application, we can distinguish fuel for heat production and fuel for transportation, and depending on the calorific value 1 we can divide fuels into low-calorie and high-calorie fuels low energy and high energy fuels.
In most cases fuels are combustible substances it means the substances capable to exothermic reaction with air after the initiation ignition. For commonly used fuels we use parameters which allow to compare the amount of energy that can be released by this reaction.
The calorific value tefhnologia a measure of the amount of heat obtained by combustion of unit of mass or volume of fuel. The calorific value of organic substances containing carbon, hydrogen, sulfur and oxygen is described by the following empirical equation: C, H 2, O 2, S are mass chdmiczna of these elements, respectively, and w is contents of water humidity of material. When combustion is total and the reaction products are brought into the standard state at constant volumethe heat obtained in this process is called the heat of combustion.
The process should be total stoichiometric, without loss of substance, no evaporation and complete to the thermodynamically most stable product. Measurements of orgwniczna of combustion cehmiczna carried out in a bomb calorimeter. The heat of combustion is called the upper calorific value, since it corresponds to the total heat produced from the fuel.
In combustion processes taking place in furnaces and engines water vapor is produced, which is not condensed. Mostly it is entrained with the other flue gases, which prevents the use of energy released during its condensation. Therefore, to evaluate the quantity of the resulting heat another parameter is more appropriate a lower calorific value. An example of the solid fuel is wood. During the combustion of wood we obtain relatively small 0.
Wood is classified as biomass and it is reproducible energy resource, unlike fossil 1 In physics and energetics a term calorific value is used whereas a term caloric value is in use in medicine.
Solid fossil fuels are peat, brown coal lignitehard coal and anthracite. It should be also remembered that the fuel can react with oxygen-containing substances eg.
H 2 O, CO 2which are externally supplied or which are produced during combustion. Combustion with oxygen insufficiency lack of oxygen is described by the equations: Reduction of the amount of exhaust gases flue gases, exhausts can be achieved by the use of oxygen-enriched air.
Combustion processes of gaseous, fluid and solid fuels undergo in different ways. Mixing the gaseous fuel with air and combustion at the burner nozzle is a process that occurs in the kinetic zone and thus it depends on the rate of chemical reaction. In contrast, when the combustible gas is mixed with air in the reaction zone furnace the process of mixing will be the reaction rate limiting factor and combustion process will take place in the diffusion zone.
The advantages of gaseous fuels include: Appropriate mixing of the reactants is to spray the fuel in the combustion chamber the liquid particles of formed aerosol pass rapidly into a state of steam. This process depends on temperature, particle fragmentation, type of fuel. During combustion process no solid or liquid residues are formed.
Solid fuels burn in multiphase system apart from the gas-solid phase cheniczna, a combustible gas fraction can be released at high temperatures. The combustion process occurs at the organicznna phase boundaryso, development of the surface and the way of mixing fuel with air is very important. In contrast to the combustion of liquids and gases, products of solid fuel combustion are not only gases but also residues such as ash and slag. Fuel can be burnt on a movable or stationary fire grate and air can be supplied from below.
The air goes through a layer of fuel and combustion occurs in a manner dependent on the fuel particle size, method of their arrangement, air velocity, fuel capacity for sintering, the amount and method of removal of generated ash. It is hard to keep a smooth combustion of solid fuel. The second method of the combustion of solid fuels involves the use of pulverized coal in specially constructed cyclone furnaces, where the effective mixing of dust from the air takes place.
Large development of the surface makes this method rapid, complete and efficient. Dust generated during the combustion is blown from the combustion chamber and separated from the exhausting gases in cyclones, filters and electrofilters. Scheme of the cyclone furnace for combustion of solid fuels by S.
General fundamentals of chemical technology, OWN Warsaw Ash produced after combustion of solid fuels is a residue of: Melting or sintering of ash, accompanied by combustion, is very unfavorable process leading to the slag formation which flood and block fire grate. Combustion Combustion is a dynamic technologja, depending on the time oxidation process involving the bogoczrk, molecules, radicals that are in one bovoczek or at the phase boundary.
The rapid exothermic reactions cause the release of energy also in the form of light flames, glowing, sparks or the formation of gradients that are the reason of heat and mass flow the flow of chemical individualsthus, the flames are moving in uncoordinated ways.
If the amount of chemicsna gas in a mixture with air oxygen gradually increases, a minimum value is reached above that a mixture becomes combustible. This minimum fuel content is called the lower combustion limit. If the yechnologia of gaseous fuel is further increased, then upper a certain value of the mixing it will be inflammable.
This is the upper combustion limit. These parameters are strongly dependent on the temperature – the higher temperature of the mixture, the bigger is difference between upper and lower limits. For some mixtures, within the lower and upper combustion limit we can distinguish the areas of explosion – when the rate of flame spread reaches a detonation explosion rate.
This problem will be discussed later. The flames formed during combustion of stoichiometric mixtures of air with the generally used fuel reach temperature K. When the composition of mixture changes reaching the limits of flammability, flame temperature drops to K. Combustion temperatures of selected gases. This might be spontaneous ignition, 2 when the amount of heat provided or dissipated inside the system is greater than allowed to discharge the heat.
The second type of ignition is the spark ignition when the flame is initiated in one place e.
Technologia chemiczna organiczna: surowce i półprodukty – Romuald Bogoczek – Google Books
Heating of combustible liquids, including liquid fuels even at temperatures below the boiling point leads to increased evaporation of the liquid, and, if they are non-volatile it can lead to secretion of volatile and flammable substances derived from their decomposition. Flash point 3 is the lowest temperature at which the tested substance heated in a specific way bogoczekk, emits a sufficient amount of technoologia products to produce with air a mixture which can be ignited being close the flame i.
If under the same conditions ignited vapour burns without external source of flame for at least 3 seconds, then this temperature is called temperature of burning. Explosions When the rapid exothermic reaction occurs in a limited space and when as a result of this technoligia gaseous products are produced, the pressure suddenly which is uncontrolled jumps increases and this is called explosion.
The amount of heat discharged is less than the amount of heat generated, chemicana in an increase of temperature and, according to the Arrhenius kinetic equation, we observe acceleration of the reaction. Self-accelerating reaction will take place faster and faster until one of the reactants runs out.
For mixtures of air or oxygen with hydrogen, hydrocarbons, vapors of sulfur, phosphorus, carbon disulfide and other organic solvents, such a process has a radical chain mechanism. Whether the tecchnologia is explosive, depends on the type of substance, mixture composition, temperature and pressure. Explosion limits combustibility, ignition are characteristic features of combustible mixtures: Outside these limiting concentrations an ignition of mixture does not occur even if the ignition source has an infinitely large energy.
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Limits of explosion expressed in concentrations are identical with the ignition limits, however, limits of explosion are dependent on the pressure and temperature, so we can talk about the temperature and pressure limits of explosion. The parameters of susceptibility to explode for selected combustible technologa and organic solvents are presented in Tables 2 and 3. Dependence of ignition energy on the composition of hydrogen – air mixture: It is a mixture of carbon monoxide and hydrogen it also contains a few percent of carbon dioxide, nitrogen and hydrocarbons.
Parameters characterizing selected organic solvents. When the combustion is performed in order to obtain heat – a process is carried out in furnaces or boilers. Then, the thermal technollogia can be converted into mechanical work e. A more direct and more effective way to convert chemical energy into mechanical work is the use of internal combustion engines more specifically, heat engines with internal combustion.
This movement is converted into the torque of the crankshaft. In spark-ignition engines Figure 3 combustion is initiated by a spark of the spark plug.
Fuels used in this type of engines may be natural gas, light fractions of petroleum liquid gas, petrol, leaded petrol as well as flammable and volatile organic substances e. Spark engines have light constructions and simple design and they easily receive high speed, high power gain, and they are easy to start. Figure 3 Scheme of four-stroke engine four-cycle engine with spark ignition.
Spark-ignition engine cycle according to Combustion and fuels edited by J. Compression ratio in combustion engines is in the 8: A measure of resistance to detonative combustion of the motor fuel for spark-ignition engines is the octane number ON.
ON for motor fuels is between and this ON value is obtained by addition of anti-knock agents, in the past the organic lead compounds were used like tetraethyl lead. Role of anti-knock agents is suppression of uncontrolled combustion by introducing radicals into the system, which in non-explosive way initiate the combustion process at a lower temperature, and at the same time they recombine with an excess of radicals generated during spontaneous ignition.