1. In-furnace calcium injection system is a pre-furnace feeding system suitable for CFB(circulating fluidized bed) boilers.
2. Since the 1980s, it has been widely used in fluidized bed boiler coal-fired power plants around the world.
3. The main principle is to spray the limestone desulfurizer in the furnace, and the fine limestone powder is pneumatically blown into a certain temperature zone on the upper part of the boiler furnace.
Limestone immediately decomposes and produces CaO and CO2: CaCO3→CaO+CO2 H=+178Kj/mol , In the furnace, some SO2 and all of the SO3 in the flue gas react with CaO to CaSO4
4. The system has the advantages of low investment, simple structure, advanced equipment, stable and reliable system operation, and is widely praised by users.
Simple system configuration, safe and reliable key valve structure
The system has few moving parts, the key components are only the feed valve, the intake valve and the discharge valve, all of which are fixed structures, and the feed valve is a contactless movement structure, which ensures the system not being prone to failure during operation and is reliable. The service life can reach 500,000 times under normal conditions. The equipment can adapt to the material conveying environment of 150 °C. It is specially designed to accommodate materials up to 350 °C. The equipment ensures complete sealing and ensures that the system operation site is clean, dust-free and pollution-free.
Large ash to gas ratio, that is, a large amount of material can be transported with less compressed air
The material is sent in the form of a gray plug, which has a high density. For example, he ratio of gray to gas is up to 80 (kg/kg) of a conveying distance of 100 meters. This saves investment in compressed air systems. Its gas consumption is only 70% of the general pneumatic conveying system, and it can also save a lot of energy and save the running cost. Its power consumption generally only is 1.1% of the power consumption of the plant.
The material moves at a low speed in the pipeline, the wear of the pipeline is small, the initial velocity is 3-4 m/s, and the final velocity is less than 7-8 m/sec, and the wear on the pipeline is extremely small.
Pipes can be made of ordinary structural steel, without special wear-resistant materials, which not only reduces the investment of pipes, but also reduces the maintenance cost of pipes.
The system has low investment and low annual operation and maintenance costs.
Due to the simple configuration of the system, the valves and equipment are safe and reliable, the maintenance and repair workload is small, and the system energy consumption is low, so the system can be safely and reliably operated at a low cost.
The world's first external double-tube conveying system, a technology that is suitable for long-distance, high-flow, low-energy transportation.
The valve pneumatic actuator has reliable performance, long service life and large thrust.
The pneumatic actuator is driven by a fully enclosed rotary straight cylinder, which converts the trajectory in the closed cavity and transmits it back. Even under severe conditions, it will not leak due to the wear of the actuator seal.
The system has a high level of control and is widely used.
The system control adopts advanced programmable logic controller (PLC), which has three control modes: automatic control, remote operation and local manual control. The system has wide applicability and is suitable for the transportation of various materials, such as: fly ash, limestone, gypsum, cement, coal, bed sand of fluidized bed boiler, boiler bottom slag, etc., all have good conveying effect.
The transmitter of the pneumatic conveying system delivers material in an embolic manner, and the hopper and transmitter do not require additional fluidization. The typical structure of the system is shown in the figure below. The system operation generally consists of five phases.
Stage 1: After feeding to the level, the feed dome valve is closed
Stage 2: Lead the conveying air to the transmitter for dense phase embolism conveying.
Stage 3: Conveying air push the ash bolt along the duct
Stage 4: The applied air pressure is maintained until the ash plug enters the ash silo
Stage 5: The air entering the ash storage is filtered by the bag filter and becomes the clean air discharged from ash storage.
The entire operation process is controlled by fully automatic PLC, and can also be operated remotely or local manually.