Modernization of manufacturing facilities

Modernization of the machining facilities

In 2018, the modernization of the machining facilities for the main products of the enterprise, i.e. graphite electrodes, began.

As part of the modernization, it was planned to carry out current repair of the building and install new machining equipment.

From 2018 to 2020, in the renovated, large and spacious building, two new automated machining lines for manufacturing large, medium and small electrodes, as well as automated nipple machining lathes and test benches were installed. The new modernized department of the machining workshop was equipped with modern aspiration and power systems, lifting and handling equipment.

The building also houses the departments for packaging, warehousing and shipment of finished products.

The new department in the machining workshop will be constructed at the end of 2020.

The new equipment will allow reaching a new level of machining quality for graphite electrodes and nipples.

Modernization of the baking facilities  

In 2018, the modernization of furnace No. 9-1 located in the third building of workshop No. 3 started according to the project of German company RIEDHAMMER, the world leader in the production of special furnaces.

From 2018 to 2020, reinforced concrete moisture protection pit in furnace No. 9-1, annular smoke flue and refractory lining of the furnace were installed, the furnace auto-baking system is being mounted, which will provide an energy-efficient technology for the first baking of electrode bodies in the furnace and high baking quality for products.

In 2018, the management of the enterprise decided to purchase and install 2 new car-bottom furnaces with raising gates for rebaking of products. Such equipment is characterized by high baking performance and guaranteed product quality. The operation of such furnaces is based on one of the latest energy efficient baking technologies at 850°C, which allows burning a part of the evaporating volatiles inside the furnace using low oxygen technology.

The mobile platform system being part of the furnaces ensures uninterrupted loading/unloading of products, and the thermal oxidation system with heat recovery ensures the environmentally friendly operation of the equipment.

From 2018 to 2020 preparatory work for the installation of rebaking furnaces were completed, and assembly work started.

The start-up of furnace No. 9-1 and 2 rebaking furnaces is scheduled for late 2020 - early 2021.

Also, as part of the modernization, in the third building of workshop No. 3, 2 (two) overhead cranes with a lifting capacity of 20 t were installed to replace worn-out cranes, new equipment for the filling material unit was manufactured and installed, new equipment for pneumatic removal of the packing material from furnace 9-1 will be supplied and installed.

One of the most important items of the modernization plan for the baking facilities   is the installation of new gas-treatment equipment for purification of flue gases from furnace No. 9-1 and existing furnace No. 10. This is a set of gas treatment equipment in which up-to-date technology is applied - the technology of regenerative thermal oxidation (RTO), in order to thermally destroy volatiles (oxidation reaction) escaping from the furnaces during the baking process.

All new equipment to be modernized and purchased has an automated control system. Automation of the baking processes at all its stages, including flue gas treatment, leads to an improvement in the environmental situation at workplaces and the overall environmental situation in the city.

With the commissioning of new furnaces, it is supposed to improve stability of carbon and graphite product properties, significantly reduce the consumption of natural gas, and the enterprise will also have an opportunity to expand the range of products and launch new types of products. The new RTO air treatment system will comply with European air quality standards (purification efficiency is 90 - 99%).

Modernization of the graphitization  facilities

In 2016, the construction of a graphitization department began, and expensive and high-tech equipment (transformer, pressure trolley, etc.) were ordered and the technology was tested on a pilot plant.

Graphitization of electrodes is conducted in electric resistance furnaces at a temperature of 2600-2900 °C. As a result of this operation, the crystalline structure and properties of graphite are artificially imparted to the carbon in the amorphous state.

In Q4 2017, a new building for lengthwise graphitization of carbon and graphite products with 8 furnaces was constructed. In 2019, 3 additional furnaces were also commissioned.

The introduction of a new technology for the graphitization made it possible to significantly improve not only the quality of products, but also, mainly, to stabilize their characteristics, which is most important for graphite electrodes used in high-power arc furnaces for steelmaking. Passage of an electric current directly through the entire electrode in the longitudinal direction, and not in the transverse direction, as the technology provides for old furnaces, made it possible to reduce the specific electrical resistance (resistivity) of graphite electrodes to 4.5 ÷ 5.5 μOhm•m. This makes it possible to improve their operational properties, as well as to use electrodes with a diameter of 500 mm, 550 mm, 600 mm, 650 mm at the consumer at higher current loads.

Trapezoid roller mills

From 2016 to 2018, four trapezoid roller mills of the MTW 138 type were installed at Ukrgrafit, that will directly improve the quality of the products.

Description of the equipment: MTW 138 trapezoid roller mill is the latest type of mill equipment. MTW-138 trapezoid mill incorporates all the best technical innovations from the mill technology and has a unique drive scheme, special lubrication system, air duct shape, etc. The bearing assembly of the main unit is sealed. The main parts of the mill are made of high-strength steel, which increases the strength of the entire mill, extending its  service life. The mill is automated one, it has low energy consumption and is easily adjustable.

Technological features of the roller mill can significantly reduce the structural imperfection of the material. The roller mill is a "dry" grinding device with a fully controlled process, in contrast to the ball mill, which is very difficult to control. Roller mill operation is based on crushing and partly on abrasion by rotating mixes, which are under the influence of centrifugal forces or spring forces, which ensures the preservation of the material structure. The destruction of the material in it occurs through a compression system using a shear force, that creates a number of additional positive effects, both technological and mechanical, which is especially important for products made from needle cokes.

Moreover, the use of roller mills makes it possible to produce a material with stable grain size distribution and specific surface area. 

Pneumatic chamber pump

In 2018, in workshop No.1 where carbon materials are produced, a pneumatic chamber pump for transporting bulk materials was installed, which ensured more stable production of material with a fraction of (1-0) mm  and to avoid hanging of the material along transportation routes.

The principle of operation of the pneumatic chamber pump is based on squeezing the material out of the chamber by compressed air. The pneumatic chamber pump operates according to the following cycle. When the upper disc valve is open, the pump chamber is filled with the required fraction, and after it is closed, air begins to flow into the chamber, which means the start of the pumping cycle. The air is supplied as long as there is material inside the chamber.

Changing the crane  over to the control from the floor level.

Since 2018, the cranes used by the enterprise are gradually being changed over to the control from the floor level.

The cranes are widely used in the workshops of the enterprise, as well as in the warehouses.

Overhead cranes, which are controlled from the floor level, are equipped with special panels that make it possible to control 3 movements: lifting the load, moving the bridge and moving the trolley. Devices of this type are easy to operate, they are compact and ergonomic. With their help, the operator controls the lifting mechanism from any convenient place. Suspension panels must be equipped with:

- Button to provide quick emergency stop;

- Reinforced feeder cable;

- Key interlock.

A specialist below can see where and how best to raise and lower the load. Another advantage is energy saving, cabin heating or lighting are not needed.

 In 2018. 8 cranes were changed over to the control from the floor level, in 2019, there were 9 cranes.

Pitch melter and mixing machines with electrical heating for workshop No.1

In 2017, modernization was carried out in workshop No. 1 with the arrangement of the receiving and processing station for dry granular coal tar pitch with an automated electrical heating system for the pitch smelting process (similar to that installed in workshop No. 2 in 2016).  5 mixing machines were also put into operation for the production of electrode paste and pitch pipeline for them, the heating of which was changed over from steam to electric one.

Availability of our own coal tar pitch processing station in workshop No. 1 will eliminate the need to transport liquid pitch from workshop No. 2, prepare pitch in the amount sufficient for production needs and, accordingly, reduce energy consumption and environmental impact. At the same time, the introduction of electrically heated mixing machines and pitch lines for them made it possible to completely change over the electrode paste production line to electric heating and to abandon the use of superheated steam in workshop No. 1, which had high losses with a significant length of outdated steam networks. In general, the modernization of the electrode paste production has made it possible to significantly optimize the operating process, improve working conditions and increase the efficiency of energy use - saving more than 3,000 Gcal of steam per year,  reducing the impact on the environment, and reducing the formation of greenhouse gases.

Pitch melter for workshop No.2

In 2016, modernization was carried out at the stage of preparation of coal tar pitch and mixing-and pressing in workshop No. 2. The modernization includes the arrangement of a receiving  and processing station for dry granular coal tar pitch with an automatic electric heating system for the pitch smelting process and the introduction of an electrically heated baking line for transporting the processed pitch to the mixing and pressing department in workshop No. 2.

The modernization and commissioning of up-to-date equipment made it possible to abandon the processing of liquid pitch supplied to the enterprise in railway thermal tanks, its pumping into steam-heated storage tanks and, thus, to increase the production standards, improve working conditions and productivity, and reduce the impact on the environment. At the same time, the change over to the electric heating made it possible to remove obsolete communications heated by superheated steam and significantly increase the efficiency of energy use by reducing the consumption of superheated steam by 4,500 Gcal per year. Accordingly, the reduction in steam consumption has made it possible to reduce the environmental impact by reducing the formation of greenhouse gases.