Steam boiler is mainly a device for producing steam, and steam is widely used in various industries as a clean and safe energy carrier. After the steam releases the latent heat of vaporization in various steam-using equipment, it becomes saturated condensate water at nearly the same temperature and pressure. Since the use pressure of steam is greater than atmospheric pressure, the heat contained in the condensate water can reach 25% of the evaporation amount, and The higher the pressure and temperature of the condensed water, the more heat it has, and the greater the proportion it accounts for in the total heat of the steam. It can be seen that recovering the heat of condensation water and effectively utilizing it has great potential for energy saving.
Benefits of condensate recycling:
(1) Save boiler fuel;
(2) Save industrial water;
(3) Save boiler water supply costs;
(4) Improve the factory environment and eliminate steam clouds;
(5) Improve the actual thermal efficiency of the boiler.
How to recycle condensate water
The condensate water recovery system recovers high-temperature condensate water discharged from the steam system, which can maximize the use of heat in the condensate water, save water and fuel. Condensate recovery systems can be roughly divided into open recovery systems and closed recovery systems.
The open recovery system recovers condensate water into the water feed tank of the boiler. During the recovery and utilization process of condensate water, one end of the recovery pipe is open to the atmosphere, that is, the condensed water collection tank is open to the atmosphere. When the pressure of the condensate water is low and cannot reach the reuse site by self-pressure, a high-temperature water pump is used to pressurize the condensate water. The advantages of this system are simple equipment, easy operation, and low initial investment; however, the system occupies a large area, has poor economic benefits, and causes greater environmental pollution. Moreover, because the condensed water is in direct contact with the atmosphere, the dissolved oxygen concentration in the condensed water decreases. If it is increased, it is easy to cause equipment corrosion. This system is suitable for small steam supply systems, systems with small condensed water volume and small secondary steam volume. When using this system, secondary steam emissions should be minimized.
In a closed recovery system, the condensate water collection tank and all pipelines are under constant positive pressure, and the system is closed. Most of the energy in the condensate water in the system is directly recovered to the boiler through certain recovery equipment. The recovery temperature of the condensate water is only lost in the cooling part of the pipe network. Due to the sealing, the water quality is guaranteed, which reduces the cost of water treatment for recovery into the boiler. . The advantage is that the economic benefits of condensate recovery are good and the equipment has a long working life. However, the initial investment of the system is relatively large and the operation is inconvenient.
How to choose recycling method
For different condensate water transformation projects, the selection of recycling methods and recycling equipment is a crucial step in whether the project can achieve the investment purpose. First of all, the amount of condensed water in the condensed water recovery system must be accurately grasped. If the calculation of the condensed water amount is incorrect, the diameter of the condensed water pipe will be selected too large or too small. Secondly, it is necessary to correctly grasp the pressure and temperature of the condensed water. The method, equipment and pipe network layout used in the recovery system are all related to the pressure and temperature of the condensed water. Third, the selection of traps in the condensate recovery system should also be paid attention to. Improper selection of traps will affect the pressure and temperature of condensate utilization, and also affect the normal operation of the entire recovery system.
When selecting a system, it is not that the higher the recovery efficiency, the better. Economic issues must also be considered, that is, while considering the waste heat utilization efficiency, the initial investment must also be considered. Because closed recycling systems have higher efficiency and less environmental pollution, they are often given priority.
Post time: Dec-15-2023
