Thermal Coal

Thermal Coal Thermal coal is a type of bituminous coal which is used to provide heat energy in combustion in various types of furnaces via the pulverized fuel method because of its high calorific value (CV). It is also sometimes called as non-coking coal, steam coal, or boiler coal. It includes all those bituminous coals which are not included under coking coal category. It is characterized by higher volatile matter (VM) than anthracite (more than 10 %) and lower carbon (C) content (less than 90 % fixed C). Its gross CV is greater than 5700 kcal/kg on an ash?free but moist basis. The greatest use of thermal coal is for the generation of steam in the boilers for the purpose of generation of electricity. Thermal coal is also used in some of the processes for ironmaking especially in the production of direct reduced iron (DRI) and in the smelting reduction processes for the production of hot metal (HM). Thermal coal is a complex heterogeneous substance. Hence, it has no fixed chemical formula. Its characteristics and hence its CV vary widely. Thermal coals like other coals also contain carbon (C), oxygen (O2), and hydrogen (H2). The other constituents in thermal coals include sulphur (S), nitrogen (N2), ash, chlorine (Cl), and sodium (Na). The quality of thermal of coals is based on the amount of C, O2, and H2 present in coal. The metallic elements in the thermal coal contribute to the coal ash. The chemical structure of the organic molecules of the thermal coal is very complex and is dependent on the rank of the coal. It varies from one coal to another coal. Typical structure of thermal coal is given in Fig 1. Fig 1 Typical structure of thermal coal The performance of the...

Strategic Planning and the Organization...

Strategic Planning and the Organization Organizational management is to plan for the future for the effective functioning of the organization. For this both the short range and the long range planning is needed (Fig 1). The idea of long range planning for the organization is rather new and was practically unknown several decades ago, but presently it is being done in most of the organizations. These days, there is hardly an organization which does not have an elaborate long range plans. Fig 1 Future planning for the organization It is rather necessary that each of the basic management decision is to be a long range decision. These days for an organization, especially in a large organization, ten years is considered to be short time span. Whether concerned with building new capacities or for introducing a new product in the market, or reorganizing the internal set up of the organization for its effective functioning, implementation of every major management decision takes years before it is really effective. And it has to be productive for years thereafter to pay off the investment made in men and money. Hence, the organizational management requires skills in making decisions with long futurity on a systematic basis. Management has no choice but to anticipate the future, to attempt to mould it, and to balance short range objectives with the long range objectives. Though looking into the future is not an easy job, yet the management is to ensure that these difficult responsibilities are not overlooked or neglected but are taken care off as well as it is to ensure that it is realistically possible. The future does not just materialize even if the management has very strong desires for it. The strong desires are not enough. The future needs decisions...

Gravity separation and Ore Beneficiation Oct12

Gravity separation and Ore Beneficiation...

Gravity separation and Ore Beneficiation Gravity separation is the oldest known ore beneficiation technique and is practiced extensively in ‘Nature’. Earliest recorded human use of gravity separation was recovery of gold by panning from the Upper Nile by ancient Egyptians, dating back to 1900 BCE. Gravity separation is a physical process which consists of the separation of different mineral types in the ore from one another based on differences in their specific gravities using the force of gravity, which can be influenced by one or more of other forces such as centrifugal force, resistance to motion by a fluid (e.g. air, water) etc. Hence, besides gravity, other factors, such as size, shape etc., also have an influence on the relative motion and thus in the separation. The effect of centrifugal action on the gravity force is given at Fig 1. It can be seen that as the gravity force increases, settling velocity of smaller particles becomes higher. Fig 1 Effect of centrifugal force on gravity force Separation of the ore particle by gravity is dependent on two factors namely (i) settling rate of the particles, and (ii) difference in specific gravity when compared against the medium in which they are being separated, this gives differential settling rate and has been termed the ‘concentration criteria’.Settling rate of a particle is dictated by ‘Stoke law’ and is equal to kd2g(Ds-Df), where k is a constant, d is particle diameter, g is force of gravity, and Ds is the specific gravity of solid and Df is the specific gravity of the fluid medium. The ‘concentration criteria’ (CC) gives an idea of the amenability of separation of two ore particles and can be expressed by (Dh-Df)/(Dg-Df) where Dh is the specific  gravity of heavier component of the ore,...

Coal for Pulverized Coal Injection in Blast Furnace...

Coal for Pulverized Coal Injection in Blast Furnace Injection of pulverized coal in the blast furnace (BF) was initially driven by high oil prices but now the use of pulverized coal injection (PCI) has  become a standard practice in the operation of a BF since it satisfy the requirement of reducing raw material costs, pollution and also satisfy the need to extend the life of ageing coke ovens. The injection of the pulverized coal into the BF results into (i) increase in the productivity of the BF, i.e. the amount of hot metal (HM) produced per day by the BF, (ii) reduce the consumption of the more expensive coking coals by replacing coke with cheaper soft coking or thermal coals, (iii) assist in maintaining furnace stability, (iv) improve the consistency of the quality of the HM and reduce its silicon (Si) content, and (v) reduce greenhouse gas emissions. In addition to these advantages, use of the PCI in the BF has proved to be a powerful tool in the hands of the furnace operator to adjust the thermal condition of the furnace much faster than what is possible by adjusting the burden charge from the top. Schematic diagram of a BF tuyere showing a pulverized coal injection lance is at Fig 1. Fig 1 Schematic diagram of a BF tuyere showing a pulverized coal injection lance Several types of coals are being used for PCI in the BF. In principle, all types of coals can be used for injection in BF, but coking coals are not used for injection since they are costly, have lower availability and are needed for the production of coke. Also, if coking coals are used for injections in BF, They lead to tuyere coking. Hence, coals used for injection...

Importance of the Organizational Management...

Importance of the Organizational Management Organizations are parts in the society structure. They are part of the community in which they function. They exist for fulfilling the specific needs of the society as well as for satisfying some of the societal purpose. Hence, it is important that the organizations function successfully so that they can fulfill the tasks for which they are set up. They are to effectively and efficiently fulfill those needs of the society for which they have come into existence. Management, in turn, is an important part of the organization. It has no function in itself, indeed, no existence in itself. Management separated from the organization it serves is not a management. Management does not function efficiently and effectively when it becomes bureaucratic, or when it start serving some special interests in the society or when it fails in making the organization to function successfully so that it can fulfill the tasks for which it has been set up. Such a management has misconceived itself as an end and the organization as a means. This is a degenerative disease to which managements are prone, and especially those managements which do not stand under the discipline of the market test. The prime objective of an effective management is to prevent this disease to arrest it, and, if get caught in the disease then it is better to get cured. The existence of the management in the organization is since there is a necessity for it to fulfill certain tasks. The success of the management is determined by how they fulfill these tasks. These tasks are three in number, equally important but essentially different, which management has to perform to enable the organization in its charge to efficiently function and to make its...