Diploma project for the reconstruction of the ring furnace of the T-2 workshop of SinTZ OJSC.

Paper

The explanatory note contains pages, figures, tables, literary sources.

ANNULAR FURNACE, RECONSTRUCTION, BURNER, LINING, HEAT BALANCE, METAL HEATING.

This diploma project is dedicated to the reconstruction of the ring furnace of the T-2 workshop of SinTZ OJSC.

To improve thermal operation, it is proposed to replace fuel-burning devices and replace the outdated furnace lining with modern refractory and heat-insulating materials.

In the diploma work, calculations of fuel combustion, metal heating, and thermal balance were made.

The calculations made in the thesis confirm the validity of the proposed methods.

The thesis presents chapters on automation, economic efficiency, safety and environmental friendliness of the project.

Introduction

OJSC Sinarsky Pipe Plant is one of the largest specialized enterprises in Russia for the production of steel stainless and cast iron pipes.

The plant was founded in 1934 in the city of KamenskUralsky (Sverdlovsk region). Repeatedly underwent reconstruction with the organization of new industries and radical improvement of existing ones.

Sinarsky Pipe Plant produces a full range of pipe products for oil producers, as well as pipes for the chemical industry, energy, mechanical engineering, construction and housing.

Today, modern production and technological bases allow you to manufacture pipes of various purposes and grades. The quality of the products not only meets all the requirements of Russian standards, but also is marked by foreign certificates of the American Petroleum Institute (API) and the German Certification Center (TVV).

In 2002, the Sinarsky plant became part of the Pipe Metallurgical Company (TMK), one of the world's leading holding companies for the production of steel and cast iron pipes, which combines under its control the four largest Russian pipe plants.

The products produced by the plant are very promising. Its uniqueness lies in the fact that it is the only enterprise in the country that produces a full range of rifled pipes used to assemble oil and gas wells.

Today, the company concentrates the most modern equipment in Europe for the production of pump-compressor pipes. In terms of capacity utilization, Sinarsky Pipe is called the most advanced plant in the industry.

The structure of the enterprise consists of the following workshops and departments:

Pipe shop;

Pipe rolling shop No. 1;

Mechanolitheic workshop;

Pipe-plating workshop No. 2 (constant development of new types of products: stainless, boiler rooms, capillary, "marine," etc.);

Pipe shop No. 2;

Pipe-plating shop No. 3;

Pipe rolling shop No. 2 (production of casing and drilling pipes, finishing of smooth pipes, production of safety parts);

Pipe rolling shop No. 3;

Central Factory Laboratory (TSL);

Medicosanitary part;

Oil Grade Pipe Shop;

Gas workshop;

Thermal Power Plant (CHP);

Repair and foundry;

Shop of konrolnoizmeritelny devices and automatic equipment (news agency instrument shop);

Energotsekh, etc.

The rolling production is represented by the procurement mill TPA140, TPA80 and TPA60.

On December 25, 1975, the TPA140 mill was put into operation as part of workshop No. T-2. The workshop is designed for the production of pipes of oil grade: drilling, casing, pump-compressor pipes and general-purpose pipes.

The furnace farm of shop No. T-2 consists of an annular heating furnace designed to heat the pipe billet before piercing and two pass-through roller furnaces designed for tempering and quenching.

In 2007, in workshop No. T-2, in order to increase equipment productivity, improve product quality and expand the range, it is planned to reconstruct pipe production, including:

Installation of a three-roll continuous mill;

Construction of the second production line;

Reconstruction of the annular furnace.

Analysis of the annular furnace showed that the furnace is a "bottleneck" in the composition of "TPA140," that is, it does not allow to increase the capacity of the mill, does not meet the requirements of the technology, does not meet the requirements of safety and ecology.

The purpose of this diploma project is to reconstruct the annular furnace, in order to reduce the percentage of scrap during heating, as well as reduce fuel consumption.

The following measures are proposed to improve the thermal operation of the furnace:

Application of modern refractory and heat insulation materials for furnace lining.

Change of gas-oil burners to high-speed burners.

General characteristics of pipe production

Development of pipe production

The products of the metallurgical industry (rolled stock, pipes, methyses and other metal products) are the main structural material. The share of ferrous metals (by weight) in the total consumption of structural materials is more than 96%.

Steel pipes occupy a significant place in metal products, the need for them is constantly increasing, and therefore production is increasing rapidly.

The wide use of pipes is due to the possibility of transporting various products along them and the excellent mechanical properties of tubular structural elements, which, with a relatively small mass, have a significant margin of safety and high resistance to bending and twisting. This allows you to use pipes instead of other profiles of metal products in mechanical engineering, energy, construction.

Pipes for main oil and gas pipelines, for drilling and operation of oil and gas wells, for offshore oil exploration are the most in demand in the world market. The stability of demand for pipes is supported by the continuous search for new oil and gas fields on land and at sea, as well as the expansion of production in old fields. In addition, many older pipelines require replacement.

However, the growth rate of pipe production has slowed slightly compared to what has been achieved. Economical types of pipes with protective coatings, with improved mechanical and operational properties, thin-walled, profile, play a more significant role in the range of products of the pipe industry of the main countries of pipe manufacturers in the world.

Tightening of working parameters of pipe use in fuel and energy complex industries - increase of well depth, pressure in pipelines, corrosive conditions during development of deep-sea and shelf deposits has a significant impact on changes in size and grade grade of the produced pipes.

The Russian pipe industry is characterized by the following: a steady pace of development, a wide variety of products, a large degree of versatility of production technology, providing the possibility of producing the same types of pipes on different equipment according to different technological schemes.

In the further development of pipe production, it is important to improve the quality of products, which requires improving the consumer properties of the initial billet, improving the technology and organization of production, improving the means and quality control system. Process processes used in pipe production shall ensure high technical, operational and consumer properties of pipes, reliability and durability of pipes by processing steel for pipes with anticorrosive coatings, high degree of standardization.

Types of steel pipes and their application

Pipes are divided by groups of production method into seamless, welded, soldered, cast.

Seamless pipes are divided into hot-rolled, cold-stretched, cold-rolled, pressed.

Welded pipes are divided into electric welded, gas-electric welded and welded by furnace welding.

Each of these methods corresponds to a certain composition of the main and auxiliary equipment.

By the type of material used, pipes are divided into non-metallic (plastic, cement) and metallic from ferrous and non-ferrous metals, bimetallic, with coatings). Pipes differ in the method of connection with each other. Joints are welded, flanged and threaded (coupling, coupling-free, nipple). According to the profile, pipes can be round, oval, rectangular, ribbed, stepped, conical, with a wall of variable size, etc. Depending on the ratio of the outer diameter to the wall thickness, the following types of pipes are distinguished: thick-walled (D/S = 79), normal (D/S = 920), thin-walled (D/S = 2040), special-walled (D/S > 50).

The size of the outer diameter of the pipe is divided into the following groups: capillary (0.34.8 mm), small (5102 mm), medium (102426 mm) and large (> 426 mm). It is also possible to classify pipes by diameter (< 70 mm, 70170, 170-500, 5001600 and > 1600 mm).

The following main groups of pipes are distinguished by purpose.

1.2.1.Trubes for oil and gas industry

The main types of steel pipes used in drilling and operation of oil and gas wells are drilling, casing and pump-compressor.

Drilling pipes are used for drilling exploratory and production wells and are manufactured with a diameter of 33.563.5 with a wall thickness of 5-6 mm for exploratory and a diameter of 60168 with a wall thickness of 711 mm for production wells.

Casing pipes are used to protect walls of oil and gas wells from destruction, water ingress into wells, as well as to separate gas-bearing and oil-bearing formations from each other and are manufactured with diameter 34219 with wall thickness 3.58 mm for exploratory wells and diameter 114426 with wall thickness 612 mm for production wells.

Tubing with a diameter of 48.3114.3 with a wall thickness of 4-7 mm is used to operate drilling wells during oil production (supply of compressed air to wells, pumping of oil).

1.2.2. Piping Pipes

In pipeline transport, pipes are used to transport oil, gasoline, gas, steam, water, air, oils, acids, inert materials (sand, crushed stone), bulk construction materials (cement, chamotte powder, etc.) and even coal.

These pipes are divided into the following types: water-gas (gas) -diameter 10.2165 with a wall thickness of 2.255.5 mm - operate at a pressure of no more than 2.5 MPa and are connected by couplings; they are manufactured mainly by furnace welding; oil pipelines - diameter 114426, wall thickness - 4.520 mm - are designed for installation of communications of in-field, prefabricated and injection pipelines; for main pipelines - diameter > 4261420, wall thickness 514 mm - are designed to transport the product from its place of production or production to the area of ​ ​ consumption; is manufactured mainly by welding.

1.2.3. Pipes for construction

Steel pipes of wide variety are used in industrial and civil construction (manufacture of columns, frames of buildings, floors, scaffolding, installation of cable networks, wiring, railings, staircases, balconies, window cornices, sports facilities, etc.).

1.2.4. Pipes for mechanical engineering

These pipes are divided into:

a) boiler houses - with a diameter of 57 the 152 with a wall thickness of 1.5 the 25 mm - are used in boilers of various designs as boiling, superheating, flame and smoke boilers, are made seamless ;

b) krekingovye-with a diameter of 19÷219 with thickness of a wall 1,5÷25 mm - are applied to pumping of hot oil products under pressure (up to 10 MPas) and also for production of heating elements of tubular furnaces, are produced from the carbonaceous and alloyed steel and delivered with smoothly cut off ends;

c) structural are used to manufacture various parts of machines. These include bearing pipes, for automotive, aviation, nuclear, medical industries, etc. Manufactured welded and seamless.

1.2.5. Pipes for receptacles and cylinders

They are used for the manufacture of various cylinders and receptacles operating at a pressure of 0.1 to 40 MPa. Pipe dimensions shall correspond to normal cylinder sizes: diameter 70465, wall thickness 2.334 mm.

Source Materials for Pipe Production

Currently, steel intended for the production of pipes is classified as high-quality. It differs from ordinary steels in its lower content of harmful impurities - phosphorus and sulfur.

The improved quality of pipe steel should be ensured by the low content of gases dissolved in it: nitrogen, oxygen, hydrogen. In addition to monitoring the content of chemical elements, some steel pipe grades are additionally subjected to special tests (for mechanical properties), as well as control macro and microstructure.

Steel is melted for pipes in open-hearth furnaces, converters and arc electric furnaces.

The starting material for the production of seamless pipes is usually calm steel, calm, semi-calm and boiling steel are equally used for welded pipes.

Advantages of boiling steel: smaller size of primary shrinkage shell; complete absence of secondary shrinkage shell; fewer non-metallic inclusions; better surface quality; higher ductility of the metal; the strength of the metal is lower and the viscosity is higher; lower cost of production.

Disadvantages of boiling steel: higher concentration of impurities; more subcortical bubbles and more difficult to control their formation; more intense ageing of metal and less resistance to corrosion.

The advantages of calm steel: less concentration of harmful impurities; no subcortical bubbles.

The disadvantages of calm steel: the size of the primary shrinkage shell is larger; the secondary shrinkage sink is significant; worse surface quality; lower metal viscosity; more expensive production.

For the manufacture of seamless pipes, boiling and semi-quiescent steel is used only for pipes of less important purpose precisely because of the high concentration of impurities and a significant number of subcortical bubbles .

Carbon-rich steels are used for large diameter pipes, which are used in the oil industry as casing and drill pipes, as well as other pipes for responsible purposes. Steels with lower carbon content are used for production of steam-line boilers and other pipes.

The quality of the raw metal largely determines the quality of the finished pipes, since the defects present on ingots or blanks are usually preserved on the finished pipes. External flaws can cause cracks, tears and captivity on pipes. In recent years, the world has mastered the production of pipes from continuous cast blanks of round, square, rectangular and multifaceted sections, which are used either directly on pipe rolling units, or, if necessary, are previously rolled.

Continuous cast blanks are cheaper and have significantly better quality than ingots obtained by traditional casting methods. The use of continuous casting provides the lowest cost for the production of blanks with a diameter of 150400 mm. At the same time, due to the difficulty of re-setting of continuous casting units, the pipe rolling unit must ensure the execution of the entire production program for using one or two dimensions of the workpiece. It is due to the latter factor and due to the presence of a large number of relatively old pipe rolling units until recently that round or square rolled and forged blanks are most useful in pipe production practice.

For production of responsible pipes with good internal surface, both forged billet and billet obtained by electric slag remelting are used, at which amount of contaminants with non-metallic inclusions is minimized. Forged billet is also used for production of seamless pipes of large diameters. The pre-deformed blank has fewer defects than ingots, since ingots are repaired before rolling at pipe-forming mills, and the splitting is cut off.

Surface defects of the pipe billet by their origin are divided into steelmaking (cracks, hairs, lacerations, non-metallic inclusions, curls, foams), defects due to heating (overheating and coke rolls) and rolling (sunsets, "lamps," scrap according to the cross section profile of the pipe billet - thick, thin, oval). Typically, the proportion of defects of rolling origin is 2030% of the total number of defects. [1]

Metal for pipes should be as cheap as possible, its quality should be high, providing minimal waste. It is known that the quality of the raw metal largely determines the quality of the finished pipes, since most non-removed defects of the workpiece are preserved on the finished pipes. In addition, billet defects contribute to the formation of additional defects during pipe rolling and a significant increase in the volume of work on repairing the finished product. Therefore, the absence of defects on the initial blank is given great attention.

Ingots are centered before rolling, and drilled to remove shrinkage shell for production of pipes of responsible purpose.

Rolled and forged billets used for production of pipes of responsible purpose are subjected to continuous blasting on centerless windings. Mechanized firing grinding of rolled and forged billet is also widely used. Typically, firing and solid blasting of the workpiece is carried out in the rolling shops manufacturing the workpiece. To detect small surface defects that are prevented by the scale layer, the preform is etched in various acids before repair. Small defects are removed by pneumatic teeth and grinding with sandstones to a depth of up to 3% of the diameter of the blank. Faces and transition radii of square blanks are ground with sandstones.

For production of pipes from high-alloyed hard-to-stitch steels and alloys, as well as bimetallic pipes of some types, centrifugal casings are used as initial billet. Prior to feeding to the pipe rolling unit, the outer and inner surfaces of the sleeves are subjected to blasting and control. Before feeding to rolled stock, blank is cut into dimensional lengths.

Classification and process characteristics of pipe production and processing methods

Methods of pipe production characterize technology of production of rough pipe from blank. Pipe processing methods include operations or groups of operations to which a rough pipe is subjected when it becomes a finished pipe that is transferred to the customer. The same method of manufacturing pipes may correspond to different methods of their processing (to a large extent depend on the purpose of the pipes) and vice versa. The technical and economic parameters depend to a large extent on the well-chosen methods of pipe production and processing.

As already mentioned, two generalized types of pipes are distinguished by groups of production methods: seamless and welded. Seamless pipes are obtained by hot and cold deformation methods from a solid or hollow blank. Welded pipes are made by various methods of welding the edges of a curved sheet. The welded pipes may be subjected to further hot or cold deformation.

Depending on the properties of the metal of the workpiece, the dimensions and the requirements for the quality of the pipes, hot deformation is carried out in several ways, each of which has its own technological advantages and disadvantages. However, regardless of the method used, the scheme for producing hot-deformed seamless pipes includes the following main technological operations: heating the workpiece, obtaining a hollow sleeve (piercing), heating the sleeve (if necessary), obtaining a pipe of intermediate dimensions (rolling the sleeve into the pipe), heating the pipe (if necessary), finally forming the diameter and thickness of the pipe wall.

The types of production of hot-deformed seamless pipes can be classified into three main distinguishing features:

1) according to the method of production of the sleeve: piercing in the Kosovo mill, piercing on the press, the combination of piercing on the press and rolling in the Kosovo mill, pressing roll piercing;

2) according to the method of rolling the sleeve into a pipe: longitudinal rolling on a fixed short mandrel (automatic mills); periodic rolling on a long floating conical mandrel with a batch supply of metal to the rolls (pilgrim mills); longitudinal rolling on a long cylindrical floating, held or partially held mandrel in a multicell mill (continuous mills); screw rolling on a long floating mandrel in a Kosovo mill (rolling mills); pushing the cups by means of a mandrel through a series of roller rings or gauge rings decreasing in diameter (rack mills); extruding the metal into an annular slit formed by a die ring and a stationary mandrel (tube-shaped presses);

3) according to the method of final formation of the diameter and wall thickness of the finished pipe: rolling in calibration, reduction or reduction-stretching mills; combination of pipe running in a rolling mill with rolling in a sizing or reduction mill; combination of rolling in a reduction and stretching mill with rolling in a Kosovo rolling mill and rolling in a calibration mill; rolling at expansion mills.

The first and third features can theoretically be combined with any of the methods of rolling the sleeve into a pipe, and therefore they are more representative not of the production method, but of the technological features and capabilities of a particular pipe rolling plant.

Most fully, the process of production of seamless pipes is characterized by a second distinguishing feature - the method of rolling the sleeve into a pipe, through which pipe rolling shops and units receive the appropriate name. In practice, pipe rolling units with a continuous mill, with an automatic mill, with a pilgrim mill, with a three-roll rolling mill, with a rack mill, with a pipe-shaped press are used.

Depending on the purpose of the pipes, the characteristics and dimensions of the starting material, welded pipes are obtained in several ways, each of which has its own technological advantages and disadvantages. Methods of manufacturing welded pipes can be classified according to two main distinguishing features:

1) by the temperature of the metal to be molded: forming a cold sheet (all types of modern pipe-electric welding units); hot sheet forming (continuous furnace pipe welding units)

2) according to the method of obtaining the final dimensions of the finished pipes: obtaining the final dimensions of the finished pipes at the calibration stands of the mold-welding units; production of limited number of pipe billets sizes on pipe welding units and final formation of wall diameter and thickness at reduction-and-extension hot or cold reduction mills.

Methods of producing welded pipes are also classified by the nature of the process (continuous and discrete), number and direction of seams on pipes (single-seam and double-seam, straight-seam and spiral-seam), a method of forming a sheet into a tubular workpiece (roll, press, in roller or half-tube machines), welding method (furnace, arc under flux layer, resistance welding, induction welding, high-frequency current welding, electric welding in inert gases, electron beam welding of pipes, direct current welding, plasma and ultrasonic welding) and the number of metal layers in the pipe (single-layer, double-layer and multi-layer).

Cold-deformed pipes are distinguished by the method of manufacturing a blank for cold conversion (seamless, welded), method of manufacturing finished pipes (cold-rolled, cold-stretched), dimensions (thin-walled, special-walled, capillary, large diameter, etc.), shape (round, ribbed, shaped), material (made of carbon and stainless steels, alloys, etc.), surface quality (hairless, electropolated, etc.), pipe metal condition (heat treated, glued, etc.), intended (for shipbuilding, for bearings, for high pressure boilers, etc.).

The processes for making cold-deformed pipes are usually multi-cyclical. Each cycle is characterized by a certain type of deformation (rolling, drawing, reduction) and the necessary sequence of finishing operations, including thermal, chemical and mechanical treatment.

Various methods of pipe treatment (thermal, chemical, application of process lubricants, mechanical treatment, straightening, calibration, etc.) are used in the process of turning a rough pipe into a finished one.

Testing and inspection of pipes includes a set of operations to verify compliance of quality and geometric dimensions of pipes with the technical requirements of standards and technical conditions. This group includes hydraulic and pneumatic pressure test operations to detect metal discontinuity, weld strength and tightness of threaded joints, inspection and change of pipe geometrical dimensions on racks, inspection of pipe quality and geometrical dimensions by NDT instruments, and pipe weighing.

Various protective coatings are applied to the pipes to prevent metal loss from corrosion when using pipes in the chemical, gas and oil industries, construction and other industries. Metal coatings are applied on pipes with diameter up to 530 mm, non-metallic - on pipes with diameter up to 2520 mm.

Special types of processing include specific operations aimed at the manufacture of pipes of special types. These are welding of locks, winding and welding of ribs, removal of grat after welding, etc. These types of machining include the fabrication and screwdriving of threaded pipe fittings and safety fittings. Specialized equipment and automatic lines are used to carry out these technological operations.

The process characteristics of the pipe production and processing methods discussed largely predetect the composition of the equipment and the technical and economic parameters of the pipe shops.

Hot Deformed Pipe Manufacturing Technology

1.6.1. Metal heating

Regardless of the method of producing hot-deformed pipes, the prepared preform undergoes a heating operation.

The correct selection of the metal heating mode largely determines the quality of the finished pipes and at the same time ensures the operation of all equipment at the lowest loads and with a lower energy consumption. Duration of preform heating is determined by physical and mechanical properties of heated metal and heat transfer conditions depending on properties of this metal, furnace design and position of preform in working space of furnace. The allowable rate of heating of the metal is limited by the stresses arising in it due to the temperature difference over the section of the heated ingot or billet. For alloyed and highly alloyed steels, these stresses are usually dangerous during the first heating period up to 500-550 ° C. For low alloy steel, this temperature range is not dangerous. The specific heating time is 10-12 minutes per 1 cm of ingot diameter and is limited by the thermal power and design of the furnace.

In order to reduce strain forces, it is always desirable to have the heating temperature highest. However, too high a heating temperature can lead to overheating causing grain growth, reducing the ductility of the steel, or even melting and oxidation of grain boundaries (burnout) and complete loss of plastic properties of the steel. Therefore, the heating temperature of carbon steel must be 150200 ° C below the melting start temperature line in the iron-carbon state diagram. Consequently, the heating temperature of the steel should decrease with increasing carbon content.

For alloyed and highly alloyed steel grades that are more sensitive to overheating and burnout, the heating temperature interval must be set more accurately, necessarily taking into account the heating of the metal during the piercing process by 3050 ° C. The heating temperature of these steels is set at 2040 ° C below the temperature range of maximum ductility determined by the method of hot twisting of metal samples during laboratory tests.

The piercing temperature of most steels must be between 1150 and 1270 ° C. Uneven heating of ingots and billets in cross section and length is an important factor.

The heating of pipes in modern furnaces in a non-oxidizing or reducing medium makes it possible to exclude the production of scale and, as a result, eliminate pipe scrap associated with the rolling of the billet and semi-product with scale, as well as metal etching. All this allows saving at least 1-3% of the metal of the mass of the workpiece for each process cycle of heating and etching. In modern workshops, heating of the initial billet is carried out in gas (ring, carousel, sectional and with walking beams) and induction furnaces. Gas furnaces with walking beams, sectional, carousel and annular, as well as induction furnaces are used for heating sleeves and pipes. The structures and thermal work of these furnaces will be discussed in more detail in the second chapter.

Process Calculations

4.1. General provisions for calculation of methodical furnaces.

The methodical furnace as a thermal unit is distinguished by the complexity of the processes of gas movement and external heat exchange flowing in its working space.

The main calculation of heat transfer makes it possible to find the necessary dimensions of the working space, the capacity of the furnace, as well as the thermal characteristics of heating

For methodical furnaces, the main technological requirements are to ensure heating to a given temperature and a given temperature difference along the metal section.

To calculate heat transfer to metal in furnaces, the continuous temperature and thermal power change along the length of the furnace is represented as a change in these values over time as the metal moves through the furnace. In this case, the calculation will be valid only in the stationary mode of operation of the furnace, when the temperature and thermal power in each section of the furnace remain unchanged over time.

When parameters of heated metal or furnace capacity change, non-stationary processes take place in continuous furnaces, after which the furnace goes into operation in a new stationary mode. This mode may differ from the previous one in both the heat distribution and the temperature distribution over the length of the furnace, but it still remains unchanged over time.

Transient modes that degrade the operation of the furnace reduce the average. This should be taken into account if the furnace is to be operated with a frequently varying grade of heated metal and variable productivity.

For the accepted physical model, the temperature field in the metal is determined by solving the Fourier thermal conductivity equation at given initial, and boundary conditions corresponding to the heating or cooling conditions.

The solution of the thermal conductivity equation is fundamentally different for the so-called thermally thin and massive bodies. Bodies whose temperature difference during heating or cooling is so small that they can be neglected are considered thin. Thus, it can be considered that the thin body is heated uniformly in section. In massive bodies, the temperature difference in the section is quite large and must be taken into account when calculating.

The boundary conditions adopted in calculating heat exchange in the working space of the furnace can be set in three ways: boundary conditions of the first kind, when the temperature distribution over the metal surface in space and in time is set; boundary conditions of the second kind when heat flux is given as a function of time; boundary conditions of the third kind, when the temperature of the heating or cooling means and the law of heat exchange between it and the metal surface are set.

When calculating the furnace, it is divided into calculated sections, bearing in mind that the boundaries of the sections must necessarily coincide with the boundaries of the heat engineering zones. To improve accuracy, heat engineering zones can be divided into several design areas, while it is desirable to combine such areas with heating zones.

When determining the number of design areas, it should be taken into account that in areas with a constant temperature, the calculation gives more accurate results than in areas with a linearly variable temperature. In this calculation, the final temperature state of the metal in the previous section will be initial for the next section. If the final temperature state of the metal is uneven, the temperature is considered parabolic to calculate the subsequent section.

Averaging of thermophysical properties can be carried out in sections.

The calculations neglect the influence of chemical processes, and the bodies involved in the heat exchange are considered gray and diffuse.

The choice of input data is based on the following considerations:

The furnace is calculated on a metal grade, during the rolling of which the mill capacity is maximum.

If the mill has the same capacity when rolling blanks of different thickness and grades of steels, then for calculating the furnace, blanks of maximum thickness from steels with a minimum coefficient of thermal conductivity are selected.

The design capacity of the furnace shall be 1015% higher than the maximum capacity of the mill.

The metal heating parameters are selected taking into account the steel grade to be heated, the dimensions of the blanks, the rolled profile, etc.

The choice of fuel is determined by technical and economic considerations that take into account the state of the fuel balance of the plant.

The choice of air and gas heating temperatures is determined by the type of fuel burned, the type of recuperator chosen, as well as technical and economic considerations that take into account the cost of fuel, construction and operation of recuperators, etc.

Setting the task of reconstruction of the ring furnace of the t-2 workshop of sints oJSC

Replacement of equipment on Shop Line No. T2 requires a change to a larger diameter of the preform to be heated (156 mm by 190 mm). Existing heating conditions in the annular furnace are unable to qualitatively heat more massive preforms. Billet discharge rate determined by piercing mill operation, independent of billet diameter, remains the same. It is necessary to increase the heat load of the furnace without increasing the residence time of the blanks in the working space of the furnace and the temperature of the working space. Increasing the heating speed while maintaining the previous rotation speed of the hearth is possible only due to increasing the heat exchange intensity. Improvement of heat exchange is possible by increasing convective component due to acceleration of combustion products movement in working space of furnace .

Currently, gas-oil burners are used for heating the furnace, from which the fuel oil nozzle is removed, since only natural gas is used as fuel. The existing design does not meet the requirements of automation, safety, as well as environmental requirements. In addition, the burner does not comply with GOST.

The diploma project proposes the replacement of obsolete gas-oil burners with TESCA burners of the HMRC series, which provide combustion product speeds of up to 150 m/s, which will increase the percentage of convective component to total heat flow from 1520% to 3540%. HMRC burners will get rid of chemical malaise and provide the required heating rate. At the same time, the mass and dimensions of the new burner are significantly smaller, compared to the old one, the cost of maintenance, fuel consumption and metal carbon monoxide are reduced.

In order to reduce heat losses to the surrounding space and increase the life of the furnace without overhaul, it is recommended to replace the old furnace lining made with refractory and heat-insulating materials: chamotte, chamotte lightweight brick, diatom, mullite corundum mass (MK90), insulating brick, asbestos board, with dense refractory concrete and mullite remodeled.

The use of refractory concrete will eliminate such existing problems as the littering of the inner wall of the inner ring, the formation of fire spots, the failure of the lining at the time of laying the blanks on the bottom of the furnace, which leads to the formation of holes and the appearance of "twins" (when switching to heating blanks of smaller diameter, the blanks roll into holes).

Refractory fiber materials and articles are progressive asbestos-free materials that provide resource conservation.

The use of insulation from fibrous material will allow:

reduce labor costs for installation by 2-3 times;

reduce the furnace weight by 912 times;

reduce the amount of heat accumulated by masonry;

decrease the total fuel consumption in the furnace.

Test Burner ® Gss Series

Recently, high-speed burners with an air-cooled combustion chamber have become the most effective burners. Such burners make it possible to completely abandon remote furnaces and create new, more economical furnace structures.

Burner is provided with efficient method of burning natural gas based on multijet distribution of gas and air and by stage mixing and combustion of combustible mixture along length of burner combustion chamber. thanks to this, TESCA burners of the GSS series, developed by the Techstroykeramika research and production enterprise (Yekaterinburg), operate in a wide range of heat loads and values ​ ​ of the excess air coefficient with the ability to control the heat and gas dynamic characteristics of the flare.

The wide functionality of the TESCA burner of the GSS series allows it to be used in the most complex heating systems. One of the distinctive features of the HMRC burner is the presence of a movable stabilizer in it, which allows ensuring stable combustion in medium and low-temperature modes without breaking the flame and extinguishing the burner.

High-speed heating technology

TESCA ® technology is based on the optimization of heating processes by distributing heat flows in a furnace with specified parameters by the temperature, speed and volume of the distributed heat carrier.

The implementation of TESCA ® technology is carried out through the use of automatic HMRC burners with adjustable flare parameters.

HMRC burners allow you to implement various heating/heat treatment: pulse, analog, combined, swing jet mode, pulsating. The specified mode is selected depending on the technical requirements of the unit.

The use of HMRC burners in heating systems allows intensifying heating processes with a high degree of temperature uniformity and improving the technical and economic performance of the furnace.

Technical features of HMRC TESCA

® burners

The HMRC burner uses new technical solutions that allow:

1. Increase the heat voltage of the flare in comparison with domestic and foreign burners by burning fuel with a high activation coefficient (K ~ 0.95).

2. Intensify the heating processes by changing the heat and power characteristics of the flare (temperature, rate and volume of coolant).

Technical solutions implemented

in TESCA ® HMRC burners

1. There are 2 mixing units in the burner: to form the main and ignition mixture. Homogeneous composition of mixture is achieved due to addition of gas and air flows, artificial turbulisation of flows, stepwise mixing along length of combustion chamber.

2. Efficient gas combustion by:

- heating of gas and air in the burner housing;

-stage combustion of fuel along the length of the burner combustion chamber;

-Recuperation of combustion products in burner housing.

3. Operation of the burner in a wide range of changes in thermal power and excess air coefficient, which allows controlling the temperature, speed and volume of combustion products (flare) at the outlet of the burner.

4. Complete combustion of fuel in the burner without additional afterburners (burners, refractory nozzles, furnaces, etc.).

5. The reduction of harmful emissions by (CO, NOx) is 2.5 times lower than the norms of the Russian Federation due to:

-stage combustion of fuel along the length of the combustion chamber;

-recirculation of combustion products in burner housing.

Project safety and environmental friendliness

Introduction

Every year, thousands of deaths or injuries are recorded during the period of production activity. In order to avoid accidents at work, it is necessary to identify the danger in a timely manner and take measures to prevent it.

Occupational safety is a condition of working conditions in which the impact on personnel of various harmful or hazardous industrial factors is excluded [27]. Occupational safety is an integral part of life safety, which is aimed at ensuring such a state of working conditions that completely exclude the impact on workers of hazardous and harmful industrial factors. Occupational safety is a complex set of technical, sanitary and hygienic and legal measures aimed at improving the health and safety of workers. The main provisions are enshrined in the Constitution and the federal law "On the basics of labor protection in the Russian Federation from 17.07.99. number 181FZ as well as legislative and other regulatory acts of the Russian Federation and republics within the Russian Federation issued in accordance with them, including the Labor Code of the Russian Federation (federal law of 30.12.2001 No. 197FZ). Increasing the technical level of the enterprise, reducing the share of manual and heavy labor, increasing the level of production equipment with fire safety, industrial sanitation, ultimately lead to improved working conditions.

Working conditions mean a combination of factors of the working environment that affect the health and working capacity of a person in the process of work. From the requirements of CMEA 172879 "Production processes," it follows that the production environment creating healthy and workable working conditions is mainly provided by the working and leisure regime, the aesthetic design of the workplace and the professional selection of workers. Improving working conditions, improving its safety affect the result of production: labor productivity, quality and cost of production. Labor productivity increases due to the preservation of human health and performance, the savings of living labor by increasing the level of use of working time, extending the period of active human labor activity, and reducing the number of accidents.

Any activity is potentially dangerous. And this danger can be significantly reduced due to a decrease in the number of maintenance personnel, remote control of process control, as well as organization of production in accordance with SSBT standards of requirements and standards for production equipment GOST 12.2. and to the production process GOST 12.3.

The purpose of this diploma project is to improve the thermal operation of the furnace by modernizing the heating system, automating the process of heating blanks, that is, full automatic control and control of the thermal mode of the furnace.

The heating process of the preforms in the furnace is monitored by the heater, it is on its timely and correct actions that the optimal operation mode of the furnace and the quality of heating depend, therefore it is very important to ensure comfortable operating conditions of the heater.

Conclusions

The organization of labor complies with the rules of equipment operation.

The fire prevention system, alarm system, as well as the presence of improvised fire extinguishing means create reliable fire protection. To ensure evacuation of personnel during fire or radiation hazard, a plan for evacuation of personnel from the workshop has been developed.

To avoid explosions of the furnace when the air supply is stopped, the furnace automation provides for an emergency shutdown of the gas supply to the furnace. We can say that all measures have been taken to prevent such a serious situation.

The following measures are used to protect workers in the pipe rolling shop No. 2 from electric shock: fencing and insulation of current-carrying parts, protective grounding, the use of low voltage currents, regular checks of electrical equipment and its insulation.

Indoor ventilation and air conditioning meet the requirements.

Microclimate meets the standards.

An analysis of the possibility of emergencies has been carried out and recommendations on actions in case of emergency have been given. Protection of workers from the consequences of emergency situations is quite reliable, but it is necessary to conduct training of workers on actions in emergency situations and modeling exercises.

Current production generally meets safety standards. However, there are such harmful factors for which there is an excess of regulatory values. To reduce harmful factors, it is necessary to use individual protective equipment, automate and mechanize manual labor.

Conclusion

In this thesis, a method of improving the thermal operation of the ring furnace of the T-2 workshop of SinTZ OJSC is proposed.

It is recommended to replace the fuel incinerators and replace the furnace lining.

In this work, calculation of fuel combustion, thermal balance, calculation of metal heating were made.

In general, the ongoing reconstruction will have the following positive results:

reducing gas consumption;

increase of furnace efficiency;

improving the quality of finished products, reducing the share of scrap,

improved environmental situation.

The thesis is considered from the point of view of economic efficiency, safety and environmental friendliness.