Sintered clay brick production process has been in existence for more than 2000 years,sintered brick is also known as red brick,is a general building wall material,the main use of raw materials are clay,cinder,lake silt,shale,etc.,through raw material preparation,green brick forming,green brick drying,green product baking,and finally fired into finished products.At present,the most advanced furnace types are rotary kiln and tunnel kiln,which can realize the automatic operation of the whole plant,and the output and quality of the products can reach the highest level.Our company can provide tunnel kiln process plan.
I.Working principle of tunnel kiln
Tunnel kiln is generally a long rectilinear channel,with fixed kiln walls and kiln roof on both sides and at the top(the top is divided into flat roof and arch roof),and kiln cars is run on the rail laid at the ground.The kiln car is loaded with products,and the kiln head enters the car and the kiln tail exits the car in turn.The kiln body constitutes a fixed pre-heating zone,firing zone and cooling zone,often called the"three zones"of the tunnel kiln.The high-temperature flue gas generated by combustion flows in the direction of the kiln head along the tunnel under the action of the chimney at the front end of the tunnel kiln or the induced draft fan,and gradually preheats the products entering the kiln,which constitutes the pre-heating zone of the tunnel kiln.The middle of the tunnel kiln is a firing zone.Cold air is pumped into the end of the tunnel kiln to cool the products in the tunnel kiln.After the cold air is heated by the products,it is pumped out and sent to the drying kiln as a heat source for drying green bricks,this section forms the cooling zone of the tunnel kiln.There are three different fuels used in tunnel kiln of fired brick:solid,liquid and gas.At present,most tunnel kilns in China use solid fuel,that is,coal.Called internal combustion sintering,where conditions exist,external sintering is also used,that is,oil and gas as combustion raw materials.
Tunnel kiln is continuous production,there is no intermittent period in the middle,the firing cycle is short,the output is large,is not affected by natural weather,and saves fuel.It mainly uses the countercurrent principle to work,so the heat utilization rate is high,and the heat utilization rate is as high as 50%compared with the conventional round kiln(also called Hoffman kiln).Tunnel kiln production can save labor,can improve the labor environment,can reduce environmental pollution,simple operation,loading and unloading products easy to realize mechanization.Reduce the labor intensity of workers.In terms of improving product quality,compared with the hoffman kiln,the secondary transportation is reduced,and the firing temperature is controllable and adjustable.It is easy to control the burning law,and the crushing rate is low.The tunnel kiln and the supporting equipment in the kiln body are relatively durable,because the tunnel kiln is not affected by the urgent cold and heat in the kiln compared with the hoffman kiln,so the kiln body has a long service life,and is generally not overhauled within 10 years.Tunnel kilns are 2/3 less in floor space than hoffman kilns of the same output and specifications.The masonry materials and equipment used in tunnel kiln and hoffman kiln are different.Therefore,the investment cost is higher than the hoffman kiln,but the later production cost is lower than the hoffman kiln.
II.The type and structure of tunnel kiln
Tunnel kilns can be classified according to internal width,output,structure,operation automation and other indicators.
(A)According to the tunnel kiln section width classification
It can be divided into 3.0m,3.3m,3.6m,4.6m,4.8m,6.9m,7.3m,9,3m,10.3m and other tunnel kilns of different widths.
(B)According to furnace structure classification
(1)According to the structure of the kiln roof,it can be divided into two structures:arch roof tunnel kiln and flat roof tunnel kiln.
(2)According to the kiln body structure,there are all brick masonry structure kiln body,brick and concrete structure with steel column,steel tie rod kiln body,and reinforced concrete frame structure kiln body.
(3)Assembly type,full fiber,block structure kiln body
(C)According to the kiln type of single line output classification
It can be divided into an annual output of 120 million bricks,80 million pieces,60 million pieces,50 million pieces,30 million pieces,20 million pieces and other specifications.
(D)According to the production process classification
It can be divided into one time loading,one and half loading and two times loading.
(5)According to the degree of operation automation classification
It can be divided into automatic measurement and control tunnel kiln,semi-automatic operation tunnel kiln,manual control tunnel kiln and so on.
III.The scope of use of tunnel kiln
As a tunnel kiln with advanced production technology,it has wide applicability and is suitable for the production of brick and tile products using coal gangue,fly ash,shale,inferior flash map and other industrial waste residues and wastes as raw materials,and is also suitable for the production of other building ceramic products.The use of this type of kiln can not only greatly reduce the labor intensity of workers,but also improve production efficiency and ensure product quality and output.
IV.The choice of tunnel kiln
The performance of various tunnel kilns is analyzed.Various factors should be considered comprehensively during construction,and suitable tunnel kilns should be selected according to the performance of raw materials and the size of investment.If the investment amount is low,investors can choose the tunnel kiln with arch roof and the side wall of the brick-concrete structure.If the investment is not very low,the tunnel kiln with flat or flat ceiling structure and reinforced concrete frame structure for the side wall is selected.For the construction projects with large output and sufficient investment,the tunnel kiln can choose the large-section one-time loading tunnel kiln with the top of the flat roof,reinforced concrete frame structure or steel frame structure or pressed steel plate structure.
All in all,the kiln type selection of tunnel kiln should focus on raw materials,total investment,product structure,market sales,comprehensive management level,technology development and other factors to judge.
V.Tunnel kiln production process
