From “Valzovka” News – Local newspaper of Rostov
SIMEM WATER TREATMENT PLANT
With a view of increasing service life of the main process equipment, ensuring correct temperature and flow modes of water supply, reduction of losses caused by shutdowns of production, now requirements for quality of cooling water are becoming particularly high. In 2007 Tube Metallurgical Company (TMC) has concluded contracts with SIMEM (Italy) for designing and supply of water treatment systems for three tube mills – VTZ, SinTZ and TAGMET. At Volzhskiy and Sinarsky tube mills SIMEM systems have provided treatment of process water for newly installed Olivotto tube heat treatment plants, and in TAGMET not only for new heat treatment plant but also for tube-rolling plant equipped with continuous PQF mill manufactured by SMS Meer.
SIMEM is an internationally renowned leader in development of technical solutions pertaining to production of high quality water with the use of modern state-of-the-art technologies designed for protection of environment and human health. In case of TAGMET, designers of SIMEM, UKRGIPROMEZ and our project development department have encountered with a very complicated problem. The problem was that our mill has no free area in our Northern site for such big projects. That is why we had to dismantle two circular sedimentation tanks at Northern pumping station and instead of them to construct a big two-storey building with floorspace of 100x40 m and 24 m high. On the second floor 24 quartz filters are installed each weighing 111 tons. Just for example we can point out that total capacity of the new water treatment line is equal to capacity of existing Northern pumping station supplying water to all shops of the Northern production site of our mill (two tube-rolling shops, second, third and fourth tube-welding shops). In the process of dismantling of circular sedimentation tanks we have executed extensive works on transferring utilities lines to new location. Within the boundaries of water treatment plants we have built 23 reinforced-concrete tanks meeting strict requirements for water tightness. Two biggest tanks have capacity of 1400 m3 each. About 1000 tons of equipment (filters, pumps, cooling towers, pipelines) have been erected on the site.
In order to prevent possible emergency situations we have built an emergency storage tank capable of providing cooling water sufficient for operation of PQF furnaces for 30 minutes after blackout at water treatment plant. Primary sedimentation tanks of rolling and heat treatment lines have been also reconstructed – new pumps, pipelines and stop valves have been installed. Furthermore we have refurbished 7-section sedimentation tank dedicated now for PQF plant. In the process of reconstruction of cooling towers of Northern pumping station new power efficient technologies have been applied. This allowed quitting the use of fans for water cooling and reducing electrical energy consumption.
In compliance with requirements of contracts concluded with suppliers of the main process equipment – SMS Meer and Olivotto, it was necessary to supply process water close in parameters to potable water. Due to this fact in the process of water treatment plant engineering it was necessary to solve three main problems: to remove suspended solids and oil, hardness salts, and get rid of biological fouling (algae, smallest shells, bacteria etc.).
All the above-mentioned problems we have successfully solved with the use of the newly installed water treatment plant. Suspended solids and oil are settled at the bottom of horizontal sedimentation tanks and further are entrapped in quartz filters. Biological fouling is removed by dosing special chemicals (biocides), which are not hazardous to human beings.
Due to the fact that process water is cooled by method of evaporation in cooling towers the hardness salts contained in the water get concentrated and are settled in heat-exchanging equipment. In order to maintain required content of salts concentration of salts in the system it is continuously and automatically measured. When critical value is reached control system gives signal for flushing, part of salted water is discharged and necessary volume of desalted water is supplied into the system. Desalted water is produced from sea water which undergoes pre-treatment in membrane ultrafiltration plants and further is desalted in reverse osmosis plant.
Quartz filters entrapping scale, graphite and oil, are getting clogged in the process of operation. For cleaning they regularly are backwashed. Sludge thus removed from the filters is dewatered on belt press filters with the use of chemical reagents. We are working now on the problem of dewatered sludge disposal.
Only 4 operators are necessary to serve water treatment plant in each shift (two for PQF rolling line and two for Olivotto heat treatment line). Though the new water treatment system is completely automated, operators are charged with responsibility to control all technological processes of water treatment and cooling, as well as adjustment of the process if necessary, preparation and dosing of chemical reagents for water treatment and sludge dewatering. Now it is possible to control water flow, pressure in the system, operation of Olivotto scale pit, etc. right from the operator working station.
Electrical engineers of water treatment plants have undergone special training in order to carry out maintenance of the new modern equipment: logical controllers, transmitters of different types, instrumentation for control of physical and chemical parameters of water. With a view of constant control of numerous water parameters we are going to organize express-laboratory. All personnel to be engaged in operation of the new water treatment will undergo training by SIMEM specialists in the process of startup and adjustment works.
We have paid special attention convenience of working conditions for service personnel of the new water treatment plant – esthetic outlook of external and internal view of the building and surrounding territory. We also have repaired the buildings of adjoining pumping stations.
In the first decade of May we have completed startup-adjustment works and cold tests of new water treatment equipment dedicated for tube-rolling shop: tests of all units have been carried out in operation – both idle and under load.
Beginning from the 10th of April new SIMEM water treatment plant provides water for PQF tube-rolling line and from 27th of April supplies water for Olivotto heat treatment plant. Now we are busy with final adjustment of technological process.
Deputy Chief Power Engineer