Coke Oven By-Product Plant Jan17

Coke Oven By-Product Plant...

Coke Oven By-Product Plant The coke oven by-product plant is an integral part of the by-product coke making process. During the production of coke by coal carburization in a coke oven battery a large amount gas is generated due to the vaporization of volatile matter in the coal. The gas is generated over most of the coking period, the composition and the rate of evolution changing during this period and being normally complete by the time coal charge temperature reaches 700 deg C. This gas is known as raw coke oven gas and is processed in the by-product plant. The functions of the by-product plant are to process the raw gas to recover valuable coal chemicals and to condition the gas so that it can be used as a clean, environmentally friendly fuel gas. After leaving the coke oven chambers, the raw coke oven gas is sprayed with flushing liquor so as to reduce its temperature to a reasonably low level and to condense the most easily condensable (high boiling point) components. The raw gas is cooled by adiabatic evaporation of some of the spray liquor to around 80 deg C and is water saturated. The temperature of the gas becomes sufficiently low so that it can be handled in the gas collecting mains. From the gas collecting main the raw coke oven gas flows into the suction main. The amount of flushing liquor sprayed into the hot gas leaving the oven chambers is far more than is required for cooling, and the remaining flushing liquor which is not evaporated provides a liquid stream in the gas collecting main. At this stage there are two streams namely a liquid condensate stream and a gas stream. The two streams pass through a butterfly control valve...

Alloy Steels

Alloy Steels Steel is basically an alloy of iron and carbon. These plain carbon steels are relatively cheap, but have a number of limitations with respect to their properties. These limitations are as follows. Plain carbon steels cannot be strengthened above 690 N/ sq m without loss of ductility and impact resistance. It is not very hardenable i.e. the depth of hardening is limited. Plain carbon steels have low corrosion and oxidation resistance. These steels must be quenched very rapidly to obtain a fully martensitic structure, leading to the possibility of quench distortion and cracking. The steels have poor impact resistance at low temperatures. The term ‘alloy steel’ is used for those steels which have got in addition to carbon other alloying elements in their composition. Alloy steels are made by combining steels with one or more other alloying elements. These elements are normally metals. They are intentionally added to incorporate certain properties in steel which are not found in the plain carbon steels. There are a large numbers of alloying elements which can be added to steel. Total amount of alloying elements in alloy steels (other than micro alloyed steels) can vary between 1.0 % and 50 % by weight. Alloy steels are usually of three types. They are microalloyed steels, low alloy steels and high alloyed steels. Microalloyed steels are a type of alloy steels that contains small amounts of alloying elements (usually 0.05 % to 0.15 %). These steels are also sometimes called high strength low alloy (HSLA) steels. The difference between the low alloy steels and high alloy steels is somewhat arbitrary. Some people define low alloy steels as those steels which contain alloying elements up to 4 %, while in second definition low alloy steels contain alloying elements up to...

Industrial Relations

Industrial Relations The term of industrial relations (IR) covers the relationship of employees with the management and the organization and also with each other. Industrial relations is concerned with anticipating, addressing and diffusing workplace issues that may interfere with an organization’s business objectives, as also with resolving disputes between and among management and employees. Traditionally, the term industrial relations is used to cover such aspects of industrial life as trade union activities, collective bargaining, employees participation in management, discipline and grievance handling, industrial disputes and interpretation of labor laws and rules and code of conduct. It includes the processes of analyzing the employer-employee relationship, ensuring that relations with employees comply with applicable central and local laws and regulations, and resolving workplace disputes. The practice of counseling, disciplining and terminating employees falls within the domain of this discipline. In the words of Lester, “Industrial relations involve attempts at arriving at solutions between the conflicting objectives and values; between the profit motive and social gain; between discipline and freedom, between authority and industrial democracy; between bargaining and co-operation; and between conflicting interests of the individual, the group and the community.” Industrial relations differs from traditional human resource management since it focus on the collective aspect of relations such as labour laws, collective bargaining, the right to strike and trade union activities etc. In short, IR consists of management of collective relations between employers and the employees. Collective bargaining is a process through which employee issues are settled through mutual discussions and negotiations through give and take approach. If the issues are not settled through collective bargaining they should be referred to voluntary arbitration but not to adjudication in order to maintain congenial relations. The three main participants in the industrial relations activities are employer’s management, employees and...

Quality Control Jan11

Quality Control

Quality Control There are two terms which are frequently used for ensuring the quality of a product or service. These terms are ‘quality control’ and ‘quality assurance’. These two terms are often used interchangeably. However these two terms differ in meaning. Quality control is an evaluation to determine needed corrective action. It is an act of guiding a process where variables are kept under constant observation and control within a range of limits. It is based on measurement and control of the parameters which can affect the quality of product or services. On the other hand quality assurance is an activity which gives confidence and make doubly sure that the things will not go wrong. Quality assurance takes place through a planned and systematic activity normally through procedures designed for meeting the quality requirements for a product or service. The ISO definition states that quality control is the operational techniques and activities that are used to fulfill requirements for quality. This definition could imply that any activity whether serving the improvement, control, management or assurance of quality could be a quality control activity. Quality control is a process for maintaining standards. Standards are maintained through a process of selection, measurement and correction of work, so that only those products or services emerge from the process which meets the standards. In simple terms, quality control prevents undesirable changes being present in the quality of the product or service being supplied. Quality control can be applied to particular products, to processes which produce the products, or to the output of the whole organization by measuring the overall quality performance of the organization. Quality control is often considered to be an activity which takes place after the event is over. This means that the quality is determined after...

Characteristics of Steel Wire Rods...

Characteristics of Steel Wire Rods Wire rod is a hot rolled intermediate steel product produced from a semi normally a billet and having a circular, rectangular or other cross-section that is typically produced in nominal diameters of 5 mm to 20 mm in irregularly wound coils, primarily for subsequent drawing and finishing by wire drawing units. The range of materials in which wire rods are produced, comprises low to high carbon steels, cold heading steels, wire drawing steels, alloy steels, spring steels, ball bearing steels, electrode quality steels, reinforcement bars, tool steels and stainless steels. Wire rods are categorized by the ‘quality’ according to end use. Industrial quality wire rods which are made from low carbon or mild steels, account for majority of wire rods production and consumption. These wire rods are primarily intended for drawing into industrial quality wire which, in turn, used for the manufacture of such products as garment hangers, wire mesh, barbed wire, nails, and fencing etc. Wire rods are produced in wire rod mills to meet needs for specific applications and quality requirements of the customers. The desired metallurgical properties are imparted by adjusting the chemistry during steelmaking as well as by rolling and cooling practices. The wire rod rolling process determines the rod’s size (diameter) and dimensional precision, depth of decarburization, surface defects and seams, amount of mill scale, structural grain size, and within limits set by the chemistry, tensile strength and other physical properties. Standards of product quality (e.g. tighter dimensional tolerances, control over residuals, and coil weight) have become tighter in recent times along the entire range of wire rods, largely in response to customer demands for improved performance on the customer’s equipment. The quality, end-uses and important characteristics of wire rods are given in Tab...