| Benefits
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In a furnace without heat recovery equipment operating on natural gas at 1200 ° C with 10% excess air, 63% of the energy input is lost in waste gases and not actually available to the process
With typical air preheats in excess of 1/3 of the furnace operating temperature, the Hotwork Recuperative Burner has the ability to recover part of this energy by exhausting hot waste gases through its specially designed quarl and over an integral metallic heat exchanger which, in turn, preheats incoming combustion air.
This heat recovery significantly reduces the amount of fuel required for the process and makes the HRB Burner ideal for applications where flue gas temperatures are high and load residence time at high temperature is long, such as forging and heat-treatment furnaces or batch-type furnaces.
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| Exhausting furnace pressure control |
Since the waste gases exhaust through the burner quarl, there is no need for a conventional flue, which speeds up design and installation of the furnace. The furnace pressure is controlled by an air-driven eductor in the burner flue arrangement.
Accurate pressure control is achieved by varying the volume of air to the eductor which in turn controls the amount of waste gases drawn out of the furnace. No separate fan is required for the air to the eductor as it is supplied by the combustion air fan. |
| Fuel savings |
The fuel saving from air preheating depends on how much heat is transferred from the exhaust gases to the combustion air (directly related to the exhaust gas temperature). Experience from operating installations indicates that air preheat temperature will be about 35% of the furnace operating temperature. |
| Extended flue |
In order to increase the residence time of waste gases exhausting through the burner and maximise the exchange of heat between the exhaust gases and the combustion air, the HRB Burners (HRB3.5 to HRB25) can be designed with an extended flue. Please note that these burners require higher combustion air and eductor air pressures. Figures are available from Hotwork Combustion Technology Ltd on request. |
| Turndown ratio& long flame design |
The turndown of the HRB on natural gas is 10/1 at furnace temperatures below 1200 ° C. Refer to the Combustion Data Table for turndown at higher temperatures. At maximum air flow and fuel only control, excess air levels better than 500% can be achieved. For applications where extra radiation is required, a long flame design is available. |
| Fuels, ignitions and flame supervision and control system |
The HRB5 and above are suitable for natural gas, LPG, gas oil (viscosity of 34 sec. Red. 1) or dual fuel arrangement. Smaller sizes are suitable for gas only. The HRB Burner is ignited by means of a premix pilot with all fuels. The burner is fitted with a sight glass and a port is provided for a UV scanner to be installed. In order to start the burner automatically and supervise the flame permanently, Hotwork Combustion Technology can also supply flame management equipment if required. |
| Compact recuperator |
The heat exchanger inside the HRB Burner is available separately, known as the Hotwork Compact Recuperator, and can be used in conjunction with a hot air burner such as the High Velocity Burner. Using the recuperator separately gives the possibility of positioning the burner and the exhaust at different locations, which may be required by certain firing patterns such as around a crucible furnace (burner at the bottom, recuperator at the top). It also enables features of certain burners such as the high velocity of the HV Burner to be used with higher fuel efficiency. |
| Thermal rating and combustion data |
The data provided if for guidance only and could vary slightly due to manufacturing tolerances
* Turndown of 50/1 (5000% XS Air) are achievable with a High Turndown Gas Inlet on fuell only control
** Required oil supply pressure normally 5.5 to 6.8 bar |
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