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DRY OUT using high-velocity hot-air burner systems

Flexible, portable heat-up service, world-wide

HOTWORK INTERNATIONAL carries out projects worldwide. To date, our teams have worked on virtually every continent, carrying-out such work (amongst other) as:

• Stress relief of pressure vessels
• Dry-out/heating of refractories
• Heat-up of all types of furnaces
• Holding furnace temperatures (temporary substitution
• for normal process heat-source)
• Melting “frozen“ metals
• Controlled cooldown of furnaces
• Tap and drain of glass furnaces
• Oxy-fuel Services

The potential applications are manifold and too diverse to fully detail in these few pages, but in effect, wherever there is a requirement for ACCURATELY CONTROLLED HEAT INPUT, then the deployment of our burner system must be a consideration.

The mobility of our crews and equipment enables us to work at virtually every point on the globe. Our equipment is readily portable and requires relatively little work-space. Consequently it is not unusual to find our equipment and personnel operating at 80-100 m elevations for the purpose of drying out refractories in 500 m long transfer ducts.

The worldwide availability of equipment and personnel, and our positive attitudes to all kinds of difficult circumstances and problems, enables Hotwork International to respond quickly to the needs of customers anywhere and anytime.

The HOTWORK INTERNATIONAL-Service:
Flexibility, Experience, Availability
365 days a year - 24 hours a day

As a result of their prompt, competent and professional performances, Hotwork International enjoys a good reputation, worldwide.

Our engineers are always available and ready to discuss your dry-out and heat-up problems at all times. Where appropriate or desirable, we will visit your plant to assess the requirements of the project and to discuss these with you in detail, on site. Once the scope of work has been agreed and established, we will submit our offer and proposals.

Our experience has shown that construction plans are subject to frequent fluctuations in timing, and for this reason we will maintain continuing liaison with you to ensure that our mobilization arrangements are moderated as necessary to accord with any changing requirements.

Once a final start date has been mutually fixed, our equipment and crew will arrive at site for installlation of burner equipment. From commencement of the actual heating process, our team will adopt day and night shift working to provide ”round-the-clock“ supervision.

In the event of any emergency situation, we are available 24 hours per day, 365 days per year to provide a prompt and speedy response.

We appreciate that such emergencies can prove expensive, and our committment is to respond positively and quickly in order to minimize client’s losses.

Why is refractory dry-out important?

Most refractory materials require water for the bonding of mortar, cement or concrete mixture used during installation.

In order to achieve the best refractory qualities, moisture needs to be removed thoroughly and carefully prior to the object plant going on-stream. Failure to carefully drive-off moisture can result in steam-explosions (explosive spalling) within the refractory resulting in chipping or major-cracking of the refractory.

The basic principle of drying-out refractories using hot-air burners has remained unchanged for decades, although in this respect, Hotwork International has further developed and refined the system and methods over recent years.

The basic principle of the system is the use of convected heat. An inhibiting factor in the use of convected heat can be stationary air layers on the refractory surface around the object vessel or furnace.

The Hotwork International hot air burner system produces high velocity emissions of hot gases, which creates a turbulent atmosphere, disturbing these stationary air layers and thus hastening the heat-transfer through the refractroy, rapidly and safety driving off any residual moisture.

The result is:

• No ingress of cold air due to “underpressure”
• Improved temperature distribution
• No “hot-spots”
• Shorter dry-out periods

Typical burner assembling situation - GAS

Our burners have a max. capacity of 250 Nm3/h natural gas and max. 5000 Nm3/ combustion air.

Flames supervision by UV-cells. In case of flame failure, gas supply will be stopped within 2 s by safety shut-off electrovalve.

Typical burner assembling situation - OIL

Our burners have a max. capacity of 200 l light oil and max. 5000 Nm3/ combustion air.
Flames supervision by UV-cells. In case of flame failure, fuel supply will be stopped within 2 s by safety shut-off electrovalve.

Typical Applications of the Hotwork International System include:

Induction Furnaces

New refractory-linings are typically heated-up over some 80 hours to 1100 °C, prior to initial hot-metal pour. High burner outlet velocities and the positive furnace pressure so created, ensure an accurately controlled uniform heat-up.

Blast Furnaces

Refractory linings of 300 mm thickness are typically dried-out to a temperature of some 500 °C using high velocity burners. The Hotwork International system is more effective than conventional methods, and burners can be provided suitable for coke-oven gas if necessary.

Coke Ovens

Coking chambers can be heated-up in some 80 hours to 1000 °C after throughwall or end-wall repairs. Typically one burner would be fired from both “coke“ and “pusher-“ ends of each chamber. The system can be applied to entire batteries from now (or after major rebuilds) so that all ovens are heated-up simultaneously.

Refinery FCC Units

A complete fluidized catalytic cracking unit can be dried-out using (say) 8 burners over a heating cycle in the order of 4 days. Typically temperatures of 500 °C are achieved in the Boiler.

We provide solutions for all industries world-wide with our unique high velocity system technology:

• Blast Furnaces
• Cowper Stoves
• Ladle Heating
• Incinerators
• Reactor Vessels
• Cylinders
• Pig Iron Troughs
• Chimneys
• Power Stations
• Spheres & Tanks
• Paper Pulp Digester
• Glass Furnaces