Natural Gas- its Characteristics and Safety Requirements...

Natural Gas- its Characteristics and Safety Requirements Natural gas (NG)  is a fuel gas which is used in steel plants as an auxiliary fuel for injection in blast furnace, for the production of gas based direct reduced iron, and for heating in various furnaces subject to local availability and the cost. NG is an environmentally friendly non renewable fossil fuel which is found in underground deposits in its gas phase. It exists as a gas under atmospheric conditions. It is basically a hydrocarbon gas mixture consisting primarily of methane. It is a clean fuel with a high efficiency. NG is normally supplied as (i) piped natural gas (PNG),  (ii) compressed natural gas (CNG), and (iii) liquefied natural gas (LNG). Modes of handling natural gas is given in Fig 1. Fig 1 Modes of handling natural gas NG is transported normally to long distances (up to 5000 kms) through a pipeline net work. The pressure of NG in the pipeline depends on several factors which include (i) quantity of gas to be transported, (ii) diameter of the pipeline,  (iii) the distances involved, and (iv) the safety of the gas pipeline and environment. However at the consumer end the pipeline pressure is generally less than 16 atmosphere. CNG is a form of natural gas which undergoes compression (200 to 250 kg/sq cm) into containers wherefrom it is relayed to consumers who, due to geographic and other reasons are incapable of connecting into the NG pipeline. CNG is storable. Unlike NG conveyed via pipelines and immediately consumed (similarly to electricity), CNG can be used for storage and for discontinuous utilization. NG compression into containers raises risk levels. LNG is made by cooling natural gas to a temperature of minus 162 deg C. At this temperature, natural gas becomes...

Types of Energy used in a Steel Plants and Energy Conservation...

Types of Energy used in a Steel Plants and Energy Conservation Energy is needed to do any work. Energy can be in the form of potential energy or it can be in the form kinetic energy. Potential energy is stored energy and for doing the work it is to be released from the storage.  Common example of potential energy are fuel energy, chemical energy and  pressure energy etc. Kinetic energy is energy due to motion and example of kinetic energy is electric energy which is the movement of electrons. Energy conservation activities are the efforts made towards reduction in energy consumption for doing a work. These efforts can be in the form of reduction of energy wastages, recovery and recycling of waste energy, and/or by improving the energy efficiency of the processes. Various forms of energy used in an integrated steel plant are described below.  Fuel energy Fuel energy is the potential energy which constitutes the major component of all the form of energies used in the steel plant. Fuel energy is used in the form of primary fuels and the byproduct fuels. Primary fuels used in steel plant are (i) solid fuels, (ii) liquid fuels, and (iii) gaseous fuels. Byproduct fuels are mainly coke oven gas recovered during coking process of metallurgical coals, blast furnace gas recovered from blast furnace during the production of hot metal, converter gas recovered during the production of steel in the basic oxygen furnace process, and coal tar fuel produced during the cleaning of the raw coke oven gas produced while coking of the metallurgical coals. Solid fuels used in the steel plant are coal and/or coke. Solid fuels constitute the highest percentage of energy consumed in steel plant. Both metallurgical (coking) coals and non coking coals are...

Improved Designs  and Campaign Life of a Blast Furnace May23

Improved Designs and Campaign Life of a Blast Furnace...

Improved Designs  and Campaign Life of a Blast Furnace The cost of rebuilding or relining a blast furnace (BF) is very high. Hence techniques to extend BF campaign lives are important and need to be pursued very actively. Large BFs usually have a slightly higher campaign output per unit volume. This difference is because larger BFs generally are of more modern design and are well automated.  Since the viability of an integrated steel plant depends on a continuous supply of hot metal (HM), which, in a plant with a small number of large BFs, puts great importance on long campaign life. The techniques for prolongation of BF campaign life falls under the following three categories. Operational practices – The control of the BF process has a major effect on the campaign life. BF is to be operated not only for meeting the production needs but also to maximize its life. Hence it is necessary to modify operating practices as the campaign progresses and in response to the problem areas for the maximization of campaign life. Remedial measures – Once wear or damage that affects the life of the BF becomes evident, engineering repair techniques are to be used or developed to maximize campaign life. Improved designs – As improved materials and equipment are developed, these are to be incorporated into future rebuilds to extend the life of critical areas of the BF, where it is cost effective to do so. Improved designs of the BF for improving the campaign life are discussed in this article. The correct design of the furnace proper is fundamental to reliable operation, metallurgical performance, sustained high productivity, long campaign life and an availability of more than 98 %. BF design has had many improvements in recent decades and campaigns...

Liquefied Petroleum Gas- its Characteristics and Safety Requirements...

Liquefied Petroleum Gas- its Characteristics and Safety Requirements  Liquefied petroleum gas is  a gas used in steel plants as a fuel gas for heating in various furnaces and in flame cutting machines of continuous casting machines. It is popularly known by its  abbreviation or short form which is LPG. LPG is also used for oxy-LPG gas cutting and welding. Sometimes it is used for carburization of steel, flame heating, flame gouging, flame hardening, flame cleaning, and flame straightening. Liquid petroleum gases were discovered in 1912 when Dr. Walter Snelling, an American scientist, realized that these gases could be changed into liquids and stored under moderate pressure. From 1912 and 1920, LP gas uses were developed. The first LPG cook stove was made in 1912, and the first LPG  fueled car was developed in 1913. The LPG industry began sometime shortly before World War 1. At that time, a problem in the natural gas distribution process cropped up. Gradually facilities were built to cool and compress natural gas, and to separate the gases that could be turned into liquids (including propane and butane). LPG was sold commercially by 1920. Like all fossil fuels, LPG is a non renewable source of energy. It is extracted from crude oil and natural gas. It is a safe, clean burning, reliable, high calorific value fuel. The main composition of LPG are hydrocarbons containing three or four carbon atoms. The normal components of LPG thus, are propane (C3H8) and butane (C4H10) (Fig 1). Small concentrations of other hydrocarbons may also be present. Depending on the source of the LPG and how it has been produced, components other than  hydrocarbons may also be present. CAS number of LPG gas is 68476-85-7  while its UN number is 1075. CAS number for propane is...

Investigation of Accidents and Incidents...

Investigation of Accidents and Incidents An accident is an undesired event and is normally defined as an unplanned event which interrupts the completion of an activity, and which may or may not include injury to the person, damage to the property and environment, or loss to the process. An incident is also an undesired event and it usually refers to an unexpected event that did not cause injury or damage this time but had the potential. Near miss or dangerous occurrence are also terms for an event that might have caused harm but had not. The term incident is used in some situations to cover both an accident as well as an incident. There are two theories for accidents/incidents. These as briefly described below. WH Heinrich’s Domino theory – As per this theory the occurrence of an injury invariably results from a completed sequence of factors, the last one of these being the accident itself. The accident in turn is invariably caused or permitted directly by the unsafe act of a person and/or a mechanical or physical hazard. Multiple cause theory – This theory states that behind every accident/incident there are many contributing factors, causes, and sub causes. These factors combine in a random fashion causing accidents. Hence the fundamental root causes are to be found and removed to prevent a recurrence. Majority of accident prevention efforts are based on knowledge gained from earlier accidents/incidents and,  hence it is important to learn as much as possible from each accident/incident. Learning from accidents/incidents can be achieved by investigating them in detail. However these investigations are to be based on fact-finding instead of fault-finding. An accident/incident investigation is a well planned analysis of an event that identifies the root cause and recommends corrective action to prevent...