Download Heat balance in Coke Oven - Fuel, Furnace and Refractory - Lecture Notes and more Study notes Sustainability Management in PDF only on Docsity! Lecture 6: Heat balance in Coke oven and clean Development Mechanism Clean Development Mechanism (CDM) Concerns with development of technologies those relate to emission reduction. CDM stimulates sustainable development and emission reduction. For development of clean technologies in the existing processing route, energy balance of a route or a process could provide useful information to evolve strategy for a new technology. Some of the benefits of energy balance. • It can identify the flow of energy. • It can determine energy losses and identify the locations (s) of losses. • Assigning temperatures to flow of energy can disclose the quality of energy. Quality of energy is directly proportional to its temperature. We may have low quality, medium quality or high quality energy. • In formations on quality and quantity of energy can be used to plan devices for energy recovery and its reuse. Illustration of CDM To illustrate the CDM by‐product coke oven is selected as an example. Coke oven is employed to produce coke. Coke is a very important raw material to produce hot metal in blast furnace in integrated steel plants. Coke‐ovens, in fact, are an‐integral part of integrated steel plants. It is well known that coke ovens produce large emissions. Consider heat balance of a Coke oven. (Material balance is given in lecture 5, problem 1). The following block diagram illustrates various heat inputs and outputs. Figure 6.1: Block diagram to illustrate the input and output of heat. Docsity.com Heat balance Heat input real Heat output real Calorific value of coal Calorific value of coke Calorific value of coke oven gas Calorific value of tar Calorific value of coke‐ oven gas Sensible heat in coke Sensible heat in coke‐ oven gas Sensible heat in tar Losses * * Losses are obtained from (Heat input‐Heat output). Heat balance discloses many important information on quality and quantity of energy. Coke oven operates at , output temperature is assumed to be . The heat output in tar, coke and coke oven gas is of high quality as they are discharged at and must be explored in terms of reuse. Also output consists of potential energy, i.e. calorific value let us consider each heat output and analyze in terms of reuse. 1. Coke: it carries both sensible heat and potential energy. Potential energy can be obtained by combustions. Sensible heat cannot be used because coke cannot be used directly in blast furnace. It is to quenched and then stored for future use. Wet quenching is employed to cool coke from to . In the wet quenching water is vaporized and released into the atmosphere. Hear the sensible heat of red‐hot coke is converted into sensible heat of water vapor and is lost unutilized. Airborne coke dust is also produced. 2. Coke oven gas: it also contains potential energy and sensible heat. One should consider usage of sensible heat and potential energy of coke oven gas. Gas existing from coke oven contains, among gaseous constituents, dust. Hence, cleaning is required which may lead to loss of sensible heat. 3. Losses: at high temperature, losses are unavoidable moreover, coal in the coke‐ovens is heated indirectly. Design of coke oven with high quality thermally conducting material may reduce heat losses. The above energy analysis shows that sensible heat of coke, which is lost in wet quenching, should be re‐used.it should also be noted that coke is the main source of thermal and chemical energy in the blast furnace iron making. Loss of sensible heat due to quenching is of coke. In an earlier Docsity.com