Iron & Steel
Over the years, the iron and steel industries have seen an increasing reliance on monolithic refractories, which are either cast or pneumatically installed. These types of installations not only provide extended service life if properly installed and dried in a controlled and uniform manner, but also result in significant cost savings to the end user.
The introduction of Hotwork's high velocity heating to the iron and steel industries has played a significant role in the success of the new generation of monolithic refractory products. As the primary supplier of Refractory Dryout & Heatup services to the iron and steel industries worldwide, Hotwork is able to provide important information and suggestions during the planning stages of refractory installations in all types of vessels, enabling a more efficient and effective dryout/heatup of these products, thus enhancing performance over the campaign life of the refractory.
Refractory Dryout & Heatup
Hotwork is the pioneer of the convective heating process, which simplifies refractory dryouts and heatups. The one-sided drying of monolithic refractories is an extremely complex transient heat and mass transfer phenomenon which includes chemical reactions throughout the dryout. Moisture trapped in a refractory lining after a furnace or vessel rebuild is especially detrimental to optimum refractory performance.
Hotwork's convective heating method utilizes rapid heat transfer at all temperature levels. Our patented burners produce high velocity combustion, which is accurately controlled from ambient to temperatures in excess of 2500°F (1370°C). This high discharge rate circulates the products of combustion evenly throughout the vessel, regardless of size and configuration, producing overall temperature uniformity. The process results in fast, even moisture removal across the entire refractory lining allowing rapid furnace startups.
| Direct Reduction Iron Installations | |
| a. | Furnace Heatup & Dryout - Facilities of this type are either vertical or horizontal design. Hotwork has performed services on most of the units installed in North and South America. In most cases, our staff worked closely with engineers and installation firms headquartered in North America and Europe & The Middle East . |
| b. | Auxiliary DRI Systems - Maximization of the DRI process requires that waste heat is conserved and that exhaust gases are processed to meet emissions standards. Hotwork has a detailed familiarity with these systems allowing proper placement of burners to cure refractory to design specifications. |
| Blast Furnaces and Associated Equipment | |
| a. | Furnace Linings - The Hotwork service allows new and repaired linings to be dried with the furnace chamber under pressure ensuring uniform temperature in all areas. The high velocity characteristics of the burners allow brickwork below the tuyere line to be dried along with the hearth and tap hole area. |
| b. | Stoves - Hotwork has developed equipment and procedures required to dryout, heatup and hold hot stoves of all designs. Using Hotwork burners of various configurations, access to combustion chambers can be achieved either through existing process burners, cleanout doors, or in the case of stoves with ceramic burners, in any port of sufficient size in the combustion chamber. |
| c. | Bustle Pipes - After removal of selected gooseneck and tuyere stock assemblies connecting the bustle pipe and tuyeres, Hotwork burners are installed around the circumference of the furnace thus providing a uniform flow of heated gasses toward the Hot Blast Main or into the furnace through the tuyeres. |
| d. | Hot Blast Mains - In most instances, burners are placed in the main at the manhead or in any other access at the remote end of the main. From there, heat is forced along the length of the main toward the bustle pipe and the furnace. |
| e. | Troughs - In all cases, drying of trough linings requires that either temporary or permanent covers must be installed before the Hotwork burners can be operated. The configuration of the trough/runner system determines the number of burners required. Most troughs require between two and six burners. |
| f. | Torpedo Car Heatup - A single Hotwork burner can heatup a torpedo car to above 2000oF. During periods where production has been halted because of emergencies or planned outages, Hotwork can maintain temperatures in the torpedo car. |
| g. | Torpedo Car Meltouts - Hotwork provides manpower and equipment to remove frozen iron from torpedo cars. Required services from the customer are natural gas, oxygen, and equipment for receiving the molten iron as the car is periodically dumped. |
| Reheat Furnaces | |
| a. | New Installations - Hotwork has dried out rotary hearth pusher and walking beam furnaces. In two recent instances, dryouts were performed on the largest furnaces of their type in North America. |
| b. | Repairs - Hotwork burners can be positioned to direct heat to specific areas of furnaces that have been repaired making it unnecessary to heat the complete furnace. |
| Vacuum Degasser Heatups - Customers utilize Hotwork to provide heatup services in degassers associated with BOF shops. The equipment is portable and is able to be moved with the vessel as it is transported from the repair area to its operational position. | |
| BOF Hold Hots - In instances where steel production is interrupted due to emergencies or planned outages, Hotwork burners can be utilized to maintain temperature in the vessel at or near operating ranges. | |
| Stack & Chimney Services | |
| a. | Lining Dryouts - Hotwork is utilized to dryout linings in new and existing repaired stacks and chimneys that contain gunned or cast refractory. Both of these services can be performed in place or at the installer's facility. |
| b. | Stack Heatups and Draft Generation - In instances where temperature in a chimney or stack has declined to a point that draft is no longer sustained, Hotwork burners are used to provide supplementary heat to regenerate draft. In other instances, the burner systems are used to maintain drafts on stacks that do not have sufficient process heat to maintain draft. |
| Tundishes - Hotwork burners and technicians are used to dryout tundish refractory linings after installation, or to maintain heat between uses. Hotwork also provides complete permanent burner systems for these applications. | |
| Ladles - Hotwork burners and technicians are used to dryout new and repaired ladle refractory linings after installation, or to maintain heat between uses during regular production or during emergency outages. Hotwork also provides complete permanent burner systems for these applications. | |
| Galvanizing Lines | |
| a. | Heatups - Hotwork burners are installed in the bath section along with the appropriate burners or ducting to direct heat into inductors that may be associated with the furnace. |
| b. | Zinc Charge Preparation - Heat provided for heating of the brickwork is also utilized to melt ingots placed in the furnace in preparation for activating inductor loops. The thermal output of the Hotwork burners allows a much higher melt rate, which speeds up the charging process. |
| Boiler Installations | |
| a. | Dryouts - Installations that have refractories in the combustion chamber or in the ash hopper are cured with Hotwork burners, which are installed through convenient cleanout doors. |
| b. | Boilouts - Heat generated during the cure of the refractory also will generate steam, which can be used to blow down piping and test valves and control systems. |