Side fired furnaces
Side fired furnaces with recuperative air preheating in steel recuperators
Fossil fuel heating principle:
The furnace is heated by a set of hot air–fuel burners situated along the both furnace sidewalls.
All burners burn all the time. In the mouth of burners, preheated air (coming from the recuperator by an insulated steel piping) is mixed with fossil fuel in controlled mixing ratio. Flames from the burners pass through the combustion area of the melting end of the furnace, and combustion gases leave the furnace through a single exhaust port in the rear wall or through two exhaust ports, each of them situated in one of the furnace sidewalls. The combustion gases are then led through an exhaust channel into one or two metal recuperators. Downstream the recuperators the combustion gases are directed to the stack or to a heat recovery equipment (decreases specific consumption energy consumption – see hereinafter), and to flue gas cleaning equipment
Smaller types of this furnace are usually equipped with single stage recuperators. For the preheating of combustion air up to 650 0C, there are used particularly double shell steel recuperators.
Larger furnaces are designed with steel tube cage recuperators with combustion air preheating up to 700 0C or with two-stage recuperators (double shell steel recuperator + steel tube cage recuperator) that can produce preheated air temperature of max. 800 0C. When using special burners, there can be added the third stage recuperator for the preheating of natural gas to max. 500 0C. In such a case, the specific energy consumption is very close to that reached in cross fired regenerative furnaces.
The furnace output can be further increased by installing electric boosting equipment that is recommended also for an improvement of the thermal homogeneity of all kinds of molten glass.
A bubbler system is usually installed in the area preceding the glass-fining zone.
For the furnaces with two exhaust port, there is used the single doghouse situated on the furnace rear wall .Batch charging is carried within the whole width of the tank.
Glass batch can be charged also over two (over one in smaller furnaces) doghouses usually equipped with oscillating batch chargers. Charging of furnaces with a single exhaust port in the rear wall is ensured by means of oscillating batch chargers via 1 or 2 doghouses situated in the side walls immediately at the rear wall.
The melting unit technological process is fully automated and controlled by automatic control system that enables one to control sequential and continuous technological processes.
The control system offers the following standard features-storing and sorting of historical values measured,complete library of predetermined user screen displays,graphic imaging of measured values in trend screens,printing of user reports and alarm signalling.
Working end of the furnace is designed in accordance with customer’s needs.
Brief technical parameters
Typical applications: All types of production
Glass type: Large furnaces Soda-lime glass
Smaller furnaces All types of glass(excl. opal glass)
Melting capacity: 3– 350 t/24h
Melting area: 6-160m2
Fuel: Natural gas, fuel oil
Specific energy consumption: 1,200 kcal/kg and more, which depends on the preheating of combustion air (natural gas), and molten glass colour, type of operation,melting capacity, cullet ratio and electric boosting capacity.
Side fired furnaces with regenerative air preheating
Fossil fuel heating principle:
The furnace is heated by means of 3-8 burner ports situated along the both furnace sidewalls. Each burner port equipped with 2-4 underport burners or 2 side port burners, or 1-2 bottom port burners as the case may be.Flames from the burner pass transversely through the combustion area of the melting end, then leave the furnace through burner ports in the opposite furnace wall, and enter the regeneration chambers on that side of the furnace. The regenerators are packed with regenerator packing made of refractory material. The regenerators are located on both sides of the furnace, and can be designed as single pass or double pass chambers.
The refractories of the regenerator packing and regenerator walls are heated up by the passing through combustion gases. Then, in predetermined time, this cycle is reversed, and combustion air then flows through the regenerator packing of the hot chamber. Heat from the refractories is transferred to combustion air that is heated up to 1,350 0C. In the mouth of the burner port, preheated air is then mixed with fossil fuel in controlled mixing ratio, and then it burns with optimum parameters in the combustion space of the melting end of the furnace.
Flame length, and therefore also the residence time of combustion gases in the furnace is limited by the width of the furnace. Furnace design also results in higher thermal loss compared with end fired furnaces.
Due to these facts, the specific energy consumption in side fired furnaces is usually higher then in end fired furnaces. Nevertheless, this furnace enables one a better setting of melting curve than the end fired furnaces, and the furnace design allows the manufacturer to provide furnace capacity amounting to 700 t/24 h.
The furnace output can be further increased by installing electric boosting equipment that is recommended also for the improvement of thermal homogeneity of molten glass in colour glass melting.
A bubbler system is usually installed in the area preceding the glass-refining zone.
The single doghouse is situated on the furnace rear wall. Batch charging is carried out in the whole width of the tank. Glass batch charging can be carried out also via two doghouses equipped with oscillating batch chargers.
The design of the furnace is mathematically modelled in the glass part and combustion space.
The melting unit technological process is fully automated and controlled by automatic control system that enables one to control sequential and continuous technological processes.
The control system offers the following standard features:Storing and sorting of historical values measured,complete library of predetermined user screen displays,graphic imaging of measured values in trend screens,printing of user reports and alarm signalling
The working end of the furnace is designed in accordance with customer’s needs.
Brief technical parameters:
Typical applications: Container glass,Flat glass,Figured glass
Glass type: Soda-lime glass
Melting capacity: 160– 500 t/24h (up to 700 t/24h for Float process)
Melting area: Usually 60m2 and larger
Fuel: Natural gas, fuel oil
Specific energy consumption: 1150 kcal/kg and more, which depends on the type and colour of molten glass, type of operation, cullet ratio, melting capacity and the capacity of electric booster heating
