RH Type Efficient Exhaust Heat Exchan – Taeda(Taida) Group Dryer Manufacturer

Technical introduction

RH efficient exhaust heat exchanger is widely applied for recycling and condensing of exhaust gas from boiler, rotary kiln and dryer. It mainly consists of heat exchanging device, ID fan, flue duct and auxiliary machines. It is also set with ash cleaning chamber and observation hole.
　　 Heat exchanging device mainly contains efficient heat exchanger, air distribution room, ash sedimentation room and outer maintenance. Different design for heat exchanging tubes can get hot air with various temperature and heat value. Temperature of heat exchanger after combining jet pipe and plug-in pipe can reach 380 to 580℃. All low and middle temperature heat exchanger adopt plug-in pipe. Temperature after heat exchanging ranges from 100 to 380℃.
　　 Air distributioin room can let high temperature exhaust gas fully distributed on front end of heat exchanger. It also has dust sedimentation function. There is ash cleaning door set at air distribution room and ash sedimentation room.
　　Texture of heat exchanger and type of heat exchanging tube
Level 1（high temperature section): front half heat exchanging tube adopts aluminized pipe. Tube plate at front half section adopts Stainless steel 304 texture. Rear half section heat exchanging tube adopts 20# boiler tube which will be processed into thread tube. Rear half tube plate adopts carbon steel texture.
Level 2 to 4: Heat exchanging tube adopts 20# boiler tube which will be processed into thread tube. Tube plate adopts Q235-A texture.

Advantages

1. Design of heat exchanger and combustion furnace adopt body-divided structure, which provides convenience for layout, installation and maintenance.
2. Taeda heat exchanger adopts tube multi-tube design and plural serial stage. Heat exchanging steel tubes are processed to thread tubes, which reduces temperature reduction of heat exchanging tube and extends service life of exchanger.
3. Adopt small-temperature difference design, which reduces temperature of flue gas at heater inlet and shrink heat exchanging temperature between flue gas and air. Although this method will increase manufacturing cost, wall temperature at high-temperature stage can be greatly reduced and service life is extended longer.
4.Flue gas recirculation cooling process is adopted to control flue gas temperature. Since flue gas generated in the combustion furnace is generally at 800-1000°C, if no cooling measures are taken before directly entering heat exchanger, common material cannot bear such high temperature. If the method of opening the furnace door to inhale a large amount of cold air is adopted, it is simple to carry out, but a huge energy will be wasted. Flue gas after cooling will be partially recirculated by circulating fan to achieve purpose of flue gas cooling. This method can save more than 10% of energy and running effect is good.
5. Process of heat exchange medium designed is that flue gas runs outside tube and the air inside tube. The advantage of this process method is that the two media can completely wash heat exchange tube bundles and utilization rate of heat exchange tube bundles is high. Heat exchanger structure and manufacturing process are simple. Free expansion can be achieved and no additional expansion mechanism is required.
6. In order to overcome the problem that dust accumulation between tube bundles in this process is not easy to remove, our company has developed and designed a high-temperature flue gas dust collector which will be placed in front of heat exchanger. Dust-containing high-temperature flue gas passes through dust collector before entering heat exchanger. More than 80% of dust is removed. The remaining small amount of fine ash with small particle size is difficult to deposit after entering heat exchanger. Most of remaining fine ash is carried out of the heat exchanger by the airflow, which can extend the ash cleaning cycle to several years. Even ash cleaning process can be omitted. .
7. According to local government regulations, there are two exhaust gas disposal methods, dust collecting and dust collecting+desufurization for customers' option.

Working principle

After primary sedimentation, high temperature flue gas will enter air distribution room of heat exchanger. Heat exchanging in air distribution room is sufficient and thermal efficiency is higher than 70%. Output temperature reaches to higher than 550℃（relevant to input exhaust heat). Because heat exchanging design is adopted, output hot air is clean hot air. Blackness of flue gas is lower than ringelman emittance Grade. Emission is lower than 150mg/Nm3.