Rolling of steel and major equipment in a Cross-country Rolling Mill Apr25

Rolling of steel and major equipment in a Cross-country Rolling Mill...

Rolling of steel and major equipment in a Cross-country Rolling Mill Most of the steel products are rolled from the cast products from continuous casting machine through a series of rolling and finishing operations. The process is called simple rolling, when two rolls of equal diameter and with axis lying in same plane rotate in opposite direction with same rotational speed, and the material being rolled is homogeneous in its mechanical properties and is acted upon only by the forces from the rolls. Rolling is the most important metal forming process. More than 95 % of ferrous and non-ferrous metals and alloys are processed to their usable shapes by rolling. Usable shapes of rolled metals are plate, sheet, strip, foil, and different sections like rail, beam, channel, angle, bar, rod, and seamless pipe etc. Two common rolling processes are hot rolling and cold rolling. The primary function of the hot rolling mill is to reheat ingot/ billet/bloom/slab (steel rolling stock) close to soaking temperature point, and then roll it to thinner and longer through successive rolling mill stands driven by electric motors. The steel rolling stock heated up to around 1,250 deg C in reheating furnace, using a solid/liquid/gaseous fuel as the primary energy source. The heated steel rolling stock is rolled in a roughing mill in number of passes where its size is reduced and its length is increased while its shape is modified. This process continues in intermediate and finishing mills also in a number of passes in each of the mill. As rolling proceeds, the length of the product increases, the size of the material reduces and the speed increases after every stand and is the speed is the highest at the end. In hot rolling, the material is rolled at...

Important Features of Rolling of Wire Rods Mar27

Important Features of Rolling of Wire Rods...

Important Features of Rolling of Wire Rods Wire rods are normally rolled in a high speed rolling mill, where steel temperature is above 1,000 deg C, maximum speed of rolling exceeds 120 metres per second (m/s) and coils of wire rod produced can be upto 10 kilometers (km) long. During rolling of wire rods, usually 25 passes to 30 passes are taken in a continuous rolling mill. Wire rod is a material which has a very wide application. From components for the automotive industry, tire cord, electrodes, connecting elements such as nuts and bolts, springs, wire and wire products, steel reinforcements, and so on, everything is based on wire rod. That is why wire rod mill is normally designed with versatility in mind. The mill being an energy intensive mill, it becomes necessary that the optimum solutions are incorporated in the mill design without compromising on the flexibility. All size ranges, materials and alloys need to be produced efficiently and with high productivity in the wire rod mill. Wire rods are required to meet the wire rod users’ requirements of surface and internal quality as well as physical, chemical, mechanical, and metallurgical properties. Wire rods undergo post-processing such as drawing, forging, or machining into desired shapes and heat treatment for enabling the product to achieve the desired strength. Thus, the wire rods are required to be capable of ensuring good performance of the produced parts wherever they are used, and at the same time, to have good workability at different stages of the post-processing. The user of wire rods has three basic requirements namely (i) to eliminate or simplify one or more of the secondary or tertiary processing to improve productivity and reduce processing cost, (ii) to improve the functionality, i.e. to extend the...

ULCORED Process Mar18

ULCORED Process

ULCORED Process ULCORED is a direct reduction (DR) process, which produces DRI (direct reduced iron) in a shaft furnace, either from natural gas (NG) or from reducing gas obtained by gasification of coal. Off-gas from the shaft is recycled into the process after carbon di-oxide (CO2) has been captured, which leaves the DR plant in a concentrated stream and goes to storage. The DRI step produces a solid product which is then melted using an electric arc furnace (EAF). The process was designed mainly in 2006 by a team led by LKAB, Voest-alpine and MEFOS. The objective of the ULCORED process was to reduce the NG consumption needed to produce DRI. It was achieved by replacing traditional reforming technology with partial oxidation (POx) of NG. Combined with CCS device, ULCORED can reduce 70 % CO2 emission compared with the average in the BF route. The concept of the ULCORED process involves separating CO2 out of the process gas. It is characterized by an effort to adopt gas based DR process to a minimized emission of green- house gases (GHG), using CO2 capture and storage (CCS) technology and at the same time to a minimized use of energy. The process is designed in a way which allows for the extraction and storage of CO2. The process is therefore also dependent on CCS with a similar in-process capture. The process is based on the utilization of a shifter to convert the carbon monoxide (CO) gas from the shaft to hydrogen (H2) together with a CO2 removal unit. This opens up a new innovative evolution of the process concept. The main features of the ULCORED DR process include (i) use of oxygen (O2) instead of air resulting into an off gas of nearly 100 % CO2 which...

Top Gas Recycling Blast Furnace Process Mar09

Top Gas Recycling Blast Furnace Process...

Top Gas Recycling Blast Furnace Process In the area of production of hot metal (HM) by blast furnace (BF), the most promising technology to significantly reduce the CO2 (carbon di-oxide) emission is recycling of CO (carbon mono oxide) and H2 (hydrogen) from the gas leaving the BF top. CO and H2 content of the top BF gas has a potential to act as reducing gas elements, and hence their recirculation to the BF is considered as an effective alternative to improve the BF performance, enhance the utilization of C (carbon) and H2, and reduce the emission of CO2. This ‘top gas recycling’ (TGR) technology is mainly based on lowering the usage of fossil C (coke and coal) with the re-usage of the reducing agents (CO and H2), after the removal of the CO2 from the top BF gas. This leads to lower the energy requirements. Because of the advantages of high productivity, high PCI (pulverized coal injection) rate, low fuel rate, and low CO2 emission etc., the TGR-BF process is considered to be one of the promising ironmaking processes in future. In TGR-BF, oxygen (O2) is blown into the BF instead of hot air to eliminate nitrogen (N2) in the top BF gas. Part of the top BF gas containing CO and H2 is utilized again as the reducing agent in the BF. CO2 from the BF top gas is captured and then stored. Several recycling processes have been suggested, evaluated or practically applied for different objectives. These processes are distinguished by (i) with or without CO2 removal, (ii) with or without preheating, and (iii) the position of injection. The concept of the TGR-BF (Fig 1) involves many technologies which include (i) injection of reducing top BF gas components CO and H2 in the...

Methods of Refining of Crude Benzol Feb26

Methods of Refining of Crude Benzol...

Methods of Refining of Crude Benzol Benzol or benzole is a mixture of hydrocarbons of the benzene series, in which benzene itself predominates, in association with certain of its homologues and various impurities. Benzol recovered from coke oven gas is called as crude benzol (CB). Crude benzol contains small quantities of a large number of impurities which consists of the unsaturated and sulphur compounds. These impurities have negative effects on the organic processes. Even insignificant sulphur impurities in benzene and toluene used in organic processes cause fast poisoning of the catalyst, and resinous substances formed as a result of polymerization of unsaturated compounds coat the catalyst surface and deactivate it. Some of these impurities have the proximity of the boiling points of the pure products. To produce pure products from CB, it is necessary to have its preliminary treatment to remove these impurities. Hence, any processing scheme includes preliminary preparation stages which ensure the removal to the required extent the components of sulphurous unsaturated and saturated hydrocarbons. There are two processes for the refining of the CB. These are (i) sulphuric acid process, and (ii) hydro-refining process. Sulphuric acid refining The refining of the CB comprises the purification of the CB and its subsequent separation into the desired commercial products. This entails chemical washing and fractional distillation. The crude benzol is washed with concentrated sulphuric acid which sulphonates the more undesirable compounds and allows easier separation and recovery of the benzene, toluene and xylene (BTX) fractions. The sulphuric acid washing removes unsaturated compounds, olefins, dienes etc. together with any pyridine and some sulphur compounds. The olefins, dienes and other unsaturated compounds are removed by the sulphuric acid, partly by polymerization and resinification, and partly by solution in the acid. The sulphuric acid method of...

Carbonization of Coal in Heat Recovery Coke Oven Battery Feb15

Carbonization of Coal in Heat Recovery Coke Oven Battery...

Carbonization of Coal in Heat Recovery Coke Oven Battery One of the present trends in the production of the metallurgical coke is the comeback of non-recovery ovens. The ovens are called non-recovery since the by-products are not recovered and are burnt during the process of coal carbonization. This is driven due to the less interest in by-products, smaller investment per annual ton, and better environmental performance. The development of non-recovery coke ovens took place in 1980s and 1990s. This technology arises from the classic beehive ovens which supplied since the eighteenth century the coke for the industrial revolution. The beehive ovens were manually operated, with small heat recovery, just for heating the oven. Now, non-recovery ovens are modern construction, with highly mechanized operation, and automated to a certain degree. The non-recovery ovens are called heat recovery ovens when the energy of the exit gases is recovered in the form of steam for generation of power. The schematics of the HR coke oven process are shown in Fig 1. Fig 1 Schematics of the process of a heat recovery coke oven The basis for the heat recovery (HR) coke ovens is the so called ‘Jewell-Thomson oven’. These ovens were developed in 1960 when three test ovens were successfully built at Vansant, VA. Several of these ovens are grouped together to form one battery. Gases generated by the combustion of the volatile matter are sent through the down-comers and further burnt to heat the oven bottom and sides. The hot flue gas is used for steam production and power generation. Jewell-Thomson oven is shaped with a rectangular ground area. The oven brick lining is composed of silica refractory material. Coal is charged onto the oven floor at the beginning of the cycle. The carbonization process is...