A model predictive controller of the blowing mode during basic oxygen furnance process

Today in Ukraine and the world, the problem of energy saving and reducing the cost of smelted steel is state of art. Metallurgical enterprises are developing in conditions of fierce competition, the main reason is that Ukrainian products are extremely energy-intensive due to the depreciation of fixed assets and outdated technological processes. The basic oxygen furnace process is a process of producing steel from liquid cast iron with the addition of steel scrap to the converter and blowing oxygen from above through a water-cooling lance. Nowadays, the production of steel by BOF process is the most popular in the world and is becoming increasingly common. The main disadvantage of the basic oxygen furnace is the need to provide the initial amount of heat (in the form of liquid cast iron) and as a consequence - restrictions on the processing of scrap metal. Reducing the cost of basic oxygen furnace steel is achieved by increasing the share of scrap metal by increasing the degree of afterburning of CO to CO2 in the cavity of the converter, by optimal control of the parameters of the blast mode using model-predictive control. The principle of model-predictive control is based on a mathematical model of the plant. This approach minimizes the functional that characterizes the quality of the process. The linear-quadratic functional was chosen. A forecasting model is proposed taking into account the constraint on changing the position of the lance and the pneumatic oxygen supply valve. It was found that the change in the rate of decarburization of the metal depends on the distance of the lance to the level of the quiet bath and affects the degree of afterburning of CO to CO2. The decarburization process is non-stationary, described by a first-order inertial model, the transfer coefficient and time constant of which depends on the melting period and the duration of the purge. The mathematical model of the blast mode of oxygen-converter melting has been improved, taking into account the influence of the blast intensity on the decarburization process of the bath, which allowed to increase the accuracy and quality of blast control in terms of changing oxygen flow during purging. The simulation results of the automatic control system show that the model-predictive regulator provides the required level of carbon dioxide in the converter gases when the flow rate of oxygen for purge changes.

Optimization and Design of Hammerheads and Fenders on Scrap Metal Shredders Based on Improved Genetic Algorithm

Dynamic unbalance force is an important factor affecting the service life of scrap metal shredders (SMSs) as the product of mass error. Due to the complexity of hammerheads arrangement, it is difficult to take all the parts of the hammerhead into account in the traditional methods. A novel optimization algorithm combining genetic algorithm and simulated annealing algorithm is proposed to improve the dynamic balance of scrap metal shredders. The optimization of hammerheads and fenders on SMS in this paper is considered as a multiple traveling salesman problem (MTSP), which is a kind of NP-hard problem. To solve this problem, an improved genetic algorithm (IGA) combined with the global optimization characteristics of genetic algorithm (GA) and the local optimal solution of simulated annealing algorithm (SA) is proposed in this paper, which adopts SA in the process of selecting subpopulations. The optimization results show that the resultant force of the shredder central shaft by using IGA is less than the traditional metaheuristic algorithm, which greatly improves the dynamic balance of the SMS. Validated via ADAMS simulation, the results are in good agreement with the theoretical optimization analysis.

Characteristics and management of scrap metal waste in Cotonou in the Republic of Benin

The development of new technology leads to the consumption of new equipment which finally becomes hazardous waste and difficult to manage. This is what was observed in the city of Cotonou in the Republic of Benin which motivated the initiative of this study, the main objective of which is to describe the mode of management of these types of waste. The data collected concerns the types of electrical and electronic equipment used by professional users and households, as well as their conditions at acquisition and their lifespans. The data were collected from households, professional users and waste pickers. After the collection, the data were entered in the Microsoft Excel 2013 spreadsheet for the analysis and then the calculations of the means, the frequencies and the production of the graphs were carried out with the SPSS 21 software. It has been revealed that among professional users, universities and administrations are major producers of scrap metal, where respectively 30% and 16% of scrap metal was recovered. According to information gathered from these players, 79% of their equipment purchases took place on the local market. At household level, radios, televisions, telephones and refrigerators are the most widely used equipment. Like other electronic and computer equipment, the households surveyed also use computers, printers, DVD players, video players, landline and portable telephones, electronic gadgets, cameras and refrigerators. At the end of its life, 66% of the households surveyed throw their equipment in the trash cans like household waste. This discarded waste is collected by the waste pickers. Among the scrap metal recovered from the latter, motorcycle and car wrecks, television sets are the most popular with respectively 16%, 15% and 14%. Next are refrigerators for 13%, batteries for 12%, followed by electronic and computer devices.

Feasibility study of a method for identification and classification of magnesium and aluminum with ME-XRT

The identification of magnesium and aluminum in scrap metal recycling has always been a difficult point. In this paper, a material identification method of multi-energy X-ray transmission (ME-XRT) based on photon counting detector (PCD) and machine learning algorithm was proposed and used to identify and classify magnesium and aluminum. This method includes three main steps: using PCD to obtain X-ray attenuation images of five energy bins, feature extraction, and the machine learning classification. The performance of several machine learning models was compared for the fine-grained classification task. The prediction results demonstrate that the best achieved recognition rates of aluminum and magnesium are 96.43% and 98.81%, respectively.

STUDY INFLUENCE THE DESIGN ОXYGEN LANCE HEAD ON THE RESULTS OF CONVERTER MELTING WITH SCRAP PREHEATING

The results of calculation of energy efficiency of the variant of technology of converter smelting with preliminary heating of scrap metal in the unit due to burning of solid fuels in modern raw material conditions of the metallurgical enterprise of Ukraine are presented. A critical analysis of the variant of converter smelting technology with the use of preheating of an increased amount of scrap metal in the charge containing briquettes of steel chips in the unit, before pouring processing iron. According to the results of the calculation of the efficiency of use of different types of fuel used for preheating of scrap metal in the unit, the rational type and technology of its use in converter smelting are determined. A direct connection between the chemical composition of briquettes, the level of their preheating and the share in the metal charge on the energy efficiency of the converter process and their chemical heat content has been established. The nature of the temperature distribution in the volume of briquettes from steel shavings, which are a part of the metal charge, is taken into account when they are preheated by oxidation of coal with oxygen supplied through the nozzles of the standard lance. A method for calculating the change in energy consumption of scrap metal during its preheating, taking into account the content of elements in the briquettes and the level of heating. The energy consumption of the converter process with preheating of the metal charge increases in proportion to the level of contamination of briquettes from steel chips with non-metallic inclusions. According to the calculations when heating briquettes by 100—800 degrees in the converter, the increase in energy consumption of the converter process is from 60 to 630 MJ / t and from 445 to 1000 MJ/t for contamination of briquettes with non-metallic inclusions of 2.47 and 7.87 % by weight in accordance. With the reduction of briquette contamination, the efficiency of preheating of the metal charge increases. The share of the impact of the level of briquette contamination on the overall energy efficiency of the converter process is on average 0.3 % of the total energy savings of 1.91—1.92 GJ / t, which is achieved by increasing the share of scrap metal in the charge.

Sacrificial Floors and Tables

A floor or table strewn with beer cans, toys, bits of scrap metal, ceramic bowls, miscellaneous electronics, and wires: a collection of things to make sound. Instrument and sound object have been sacrificed for a music of things. DIY electronic music and maker communities have challenged what sound is made with and to what end. Within these communities, the sacredness of the musical instrument has been debunked. Percussion is examined in relation to a music of things and object-orientated performance, and the performance-table is also viewed in the context of experimental sound and performance works. In this chapter George Brecht’s The Cabinet and readymade actions, and the performance-tables of Keith Rowe and Adam Bohman are illustrated. In addition, the work of Tetsuya Umeda is used to demonstrate performance-installation where making and unmaking are seen as critical parts of performance.

“Very old Chinese bells, a large number of which were melted down”

In the second half of the 19th century, Buddhist bells from Japan began to arrive in Switzerland. The fact that these were objects listed in the so-called ethnographic collections is not surprising and the history of collecting has been a subject of postcolonial research. However, remarkably, the travel route of these bells, some of which weighed over a ton, could not be documented. Until now, the way how the bells were imported into Switzerland as unknown, and the problem of their provenance unsolved. This article argues that a global history approach provides new insights in two respects: The consideration of materiality allows a new nderstanding of the objects, while the activities of local collectors, seen from a micro-global point of view, reveal the local imprints of the global. Within this rationale, a history of individual bells in the possession of individual art lovers and museums translates into a history of scrap metal trade, allows to consider the disposal of disliked objects at their place of origin, and opens up a global framing of local history. Using global history as a concept, the historicity of the global gains visibility as we look at the intersection of materiality and the local involvement of global networks. Ultimately, as we follow the journey of the bells, reinterpreting scrap metal into art has formed a striking way in which local history assimilates the global.

ASSESSMENT OF OUTDOOR RADIATION EXPOSURE LEVELS AND HUMAN HEALTH RISK IN A MAJOR SCRAP METAL MARKET IN ABUJA

Background: Scrap metal can contain sources of radiation with the associated environmental and health risks. Radioactive substances can become associated with scrap metal in various ways and if not discovered they can be incorporated into steel and non-ferrous metals through the melting process. This can cause health hazards to workers and to the public as well as environmental concerns Objectives: this study aimed at assessing the outdoor radiation exposure levels and human health risk in a major scrap metal market in Abuja, FCT. Method: An in-situ measurement approach was adopted using a factory calibrated Radiagem-2000 Universal Survey Meter and a handheld Global Positioning System (Garmin GPS 76S) equipment. The monitor was suspended in air at one meter above the ground level. Readings were obtained between the hours of 1200 and 1600 hours since the exposure rate meter has a maximum response to environmental radiation within these hours. Results: The results showed that the average values for the outdoor exposure dose rate for the three location ranges from 0.173±0.042 μSv/h to 0.177±0.046 μSv/h with a mean of 0.176±0.045 μSv/h. These values, though, slightly higher than the standard background radiation of 0.133 μSv/h,are below the ICRP maximum permissible limit of 0.57 μSv/h. The results also show that the AEDE values are lower than the ICRP recommended limits of 1.0 mSv/y for the public and 20 mSv/y for occupationally exposed workers. The ELCR ranges from 0.5926 x 10-3 to 0.6049 x 10-3 with a mean of 0.6008 x 10-3 which is 2.1 times higher than the world’s average. The dosage to organs received shows that the testes have the highest dose while the liver has the lowest dose. The result of the dose to the organs showed that all the values are below the international tolerable limits. Conclusion: Generally, The radiological assessment shows that the study area does not constitute any immediate radiological health effect on the workers and the general public due to radiation exposure rate.