I. Product Applications and Advantages

The deaerator is a key piece of equipment in boilers and heating systems. The severe losses caused by oxygen corrosion to the boiler feed water pipes, economizers, and other auxiliary equipment annually have garnered increasing attention from the National Electric Power Department. The department has issued the GB1576-2001 "Water Quality Standard for Industrial Boilers" and the "Safety Supervision Regulation for Pressure-type Deaerators in Power Stations," which set departmental standards for oxygen content in deaerators. Specifically, the oxygen content in the feed water of low-pressure deaerators should be less than 15 μg/L, and for high-pressure deaerators, less than 7 μg/L.

The heat transfer, mass transfer methods, and deoxygenation capacity of the spiral membrane deoxygenator differ from those of the existing spray and watering pan types. It is a new type of thermal deoxygenator, which has won the Science and Technology Innovation Award for New Technology and New Products from the Power Ministry and is listed as a key promotion product by the Power Ministry. The spiral membrane deoxygenator has been proven to have the following advantages after use:

High deoxygenation capability, with a 100% pass rate for the oxygen content in the water after deoxygenation.

2: Stable operation with no vibration. Suitable for vacuum start-up and sliding pressure operation, reducing the need for complex manual adjustments during start-up and operation.

3: High adaptability; not strict requirements for water quality and temperature; can operate beyond capacity by 50% for short periods.

4: Steam volume less than 0.1% of the inlet water volume; no additional exhaust cooler is required. Optimized equipment, reduced heat consumption, and consumes 1/3 less energy than other types of heat exchangers with the same output.

II. Technical Specifications and Matching Parameters

CYG Series New Type Pressure Oxygen Remover

Section 3: Structure and Principle (Illustration Included)

The structure of the rotary membrane oxygen remover consists of the oxygen removal head and the water tank. The oxygen removal head is composed of six main parts: the outer shell, the rotary membrane assembly, the water grate, the liquid-gas mesh, the steam distribution plate, and the steam-water separator. The water tank is made up of the main body and accessories.

1. Shell: Welded from the筒 body and stamped elliptical end caps.

2. Membrane Assembly: Composed of water chamber, membrane tube, condensate connection, and make-up water connection. Both the membrane tube and the drain pipe are made of stainless steel, requiring no maintenance throughout the year, and are a key component of the rotary membrane deaerator, removing 98% of the oxygen.

3. Water Spray Grating: The water for oxygen removal in the membrane formation section and the condensate introduced by the drain pipe are here reduced in flow and redistributed, creating a uniform sprinkling effect to protect the lower liquid-vapor network. The grating's open area is not less than 50% of the total cross-section. Made of stainless steel, it operates continuously without the need for maintenance.

4. Filling Liquid-Vapor Grid: Consisting of spaced flat steel strips and a cylindrical shell, it is internally fitted with two layers of specially designed 0.3mm O-shaped stainless steel flat wire mesh. Here, water is in thorough contact with the secondary steam, heated to saturation temperature and deeply deoxygenated to ensure the oxygen content of the deoxygenated water.

5. Steam Distribution Plate: The main heating steam is introduced here, the uniform distribution structure ensures excellent heating quality, making the heating steam evenly distributed. It rises to heat softened water under no throttling conditions, working to deoxygenate at saturation temperature.

6. Air-Water Separator: Composed of stainless steel filling material, the inner network is designed with a ventilation structure, which effectively separates and returns the water carried by the exhaust gas during oxygen排放, making it an indispensable component for ensuring exhaust gas is water-free.

7. Tank: Welded from a cylindrical body and a stamped elliptical head, internally equipped with reinforcing rings. The base is mounted on a prefabricated workbench, with one end fixed and the other for installing the expansion roller assembly. The tank is equipped with manholes for maintenance, safety valve connection ports, drain outlets, reboiling pipe openings, water seal cylinders, level gauge interfaces, pressure gauge ports, temperature gauge ports, and water intake ports.

The basic principle of deaerator thermal deaeration: In the container, the amount of gas dissolved in water is proportional to the partial pressure of the gas above the water surface. The main method of thermal deaeration is to use steam to heat the feed water, raise the water temperature, and gradually increase the partial pressure of steam above the water surface while decreasing the partial pressure of dissolved gases. This causes the dissolved gases to continuously escape. When the water is heated to the boiling temperature at the corresponding pressure, the surface is entirely steam, the partial pressure of dissolved gases is zero, and the water no longer has the ability to dissolve gases, meaning that gases dissolved in the water, including oxygen, can be removed. The effectiveness of deaeration depends on whether the feed water is heated to the boiling temperature at the corresponding pressure and on the rate of dissolved gas removal, which is greatly related to the size of the contact surface area between water and steam.

Principle of operation for the spiral membrane oxygen-removing unit (jet, entrainment, turbulence, heat transfer, mass transfer, water film skirt, rain-like, saturated)

Condensate and make-up water first enter the water chamber of the inner rotating membrane element in the deaerator, and under a certain pressure difference, they are斜旋喷向 the inner cavity through small holes in the membrane tubes, forming a jet. Due to the inner cavity being filled with rising heated steam, the water in the jet draws in a large amount of heated steam (experiments have proven the jet's entrainment effect); a剧烈的 mixing and heating occurs over a very short distance, causing a significant increase in water temperature. The rotating water continues to spiral down the inner wall of the membrane tube, forming a swirling water film skirt (the critical Reynolds number of the water decreases significantly during rotation, causing turbulent churning). At this point, the turbulent state of the water has the most ideal heat transfer and mass transfer effects, reaching the saturation temperature. Oxygen is then separated out, as it cannot diffuse freely in the inner cavity and must rise with the steam through the exhaust pipe to the atmosphere. The water from the rough deaeration section and the condensed water introduced through the drain pipes are mixed here for secondary distribution, falling in a uniform sprinkling pattern onto the liquid-vapor grid below, and then undergoes deep deaeration before flowing into the water tank. The oxygen content in the water within the tank is less than 7 mg/L at high pressure and less than 15 mg/L at low pressure, meeting the departmental operating standards.

Due to the oxygen-removing drum maintaining the water in a turbulent state during operation and having a sufficiently large heat exchange surface area, the better the heat and mass transfer effects are, the less steam is exhausted (meaning less steam used for heating, resulting in smaller energy losses and significant economic benefits). The excellent deoxygenation effect allows the oxygen-removing unit to operate at an overload (usually up to 50% over the rated output for a short period) or to meet operational standards under low water temperatures and full water make-up.

4. Installation, Operation, and Maintenance

1. The installation, operation, and maintenance of deaerators, water tanks, and accessories should be carried out according to the CYD(G) type deaerator system diagram and <<Safety Supervision Regulations for Deaerators in Power Stations>>.

2. The deaerator should be placed above the feed pump, and the vertical distance between the lowest water level of the deaerator tank and the centerline of the feed pump should be no less than 6 to 7 meters. The bottom plate of the tank support should be in firm contact with the concrete.

3. Install temperature transmitters and flow sensors on the deaerator's inlet water pipe, a level transmitter on the deaerator, to detect signals such as inlet water temperature, flow rate, and deaerator water level. Input these signals into the calculation and processing module to control the hydraulic and thermal conditions of the deaerator's water intake and heating steam for achieving the desired deaeration effect. Ensure the deaeration temperature is maintained at (104±1.5℃). Adjust the electric actuator regulating valve installed on the steam pipe to heat the steam, automatically adjusting the steam flow rate based on the temperature of the deaerated water. After topping up is complete, the electric actuator automatically shuts off.

4. The lower part of the water tank is equipped with a reboiler tube, which is used for heating and deoxygenating the water during boiler filling and unit startup. For the first use, slowly open the reboiler heating tube valve at the bottom of the water tank when the water level exceeds half, to heat the water inside the tank and maintain it in a boiling state. Stop using it once the unit is started up and loaded. Additionally, a anti-rotation plate is installed at the outlet tank opening to prevent water whirl at low water levels, thereby increasing the effective volume of the water tank. Tests have proven that water whirl has a significant impact on pump cavitation. Without the anti-rotation plate, the water level in the tank must be maintained at three times the pipe diameter. With the anti-rotation plate, it can be reduced to below 1.5 times.

5. After the deaerator and water tank are field-welded, a hydrostatic test should be conducted. The pressure parameters for the hydrostatic test are: 0.2 Mpa for atmospheric deaerators and 0.75 Mpa for pressure deaerators. Prior to being sent to the deaerator, the condensate steam should be accumulated in the intermediate storage tank as much as possible, and then evenly distributed into the deaerator to ensure stable deaerator load.

6. Protective and Alarm Systems for the Rotating Membrane Oxygen Remover

(1) The water tank and deaerator are equipped with an adequate number of full-blow safety valves, with the quantity and specifications meeting the design technical specifications.

(2) Oxygen Remover with Rotating Membrane should be equipped with both local and remote water level gauges, and should have high and low water level alarms as well as high and low water level action devices. The oxygen remover water level change control: when the water level drops, the softening water pump (condensate pump) is automatically started to replenish water to the oxygen remover; when the water level rises, the pump automatically stops.

7. For the cold start of the deaerator, it is advisable to preheat the shell with auxiliary steam for 10-15 minutes. Under a certain steam pressure, send the demineralized water into the deaerator head, while adjusting and increasing the steam inlet valve to heat the feed water to nearly the saturation temperature of the deaerator operating pressure (i.e., around 102-104°C).

8. Adjust the water level control system to maintain the water level in the tank within ±100mm of the normal level. (When both deaerators need to operate in parallel, to balance the pressure and water level within the deaerators, each deaerator tank must have a connecting pipe for steam and water to maintain balance. Aim for consistency in pressure, water temperature, and water level as much as possible.) When the water level reaches ±200mm from the normal level, the high-level drain valve (electromagnetic gate valve) should open freely to drain water, and it should automatically close when the water level decreases. During operation, regularly check the responsiveness of the electric water level control system and the operation of the make-up water regulating valve.

9. Gently open the top exhaust valve, open the valves on the steam pipeline, provide steam for heating, and record the steam pressure and temperature. Adjust the exhaust valve to typically open to 2/3, allowing the exhaust flow to be around 2-3kg per ton of deoxygenated water.

10. When operating the deaerator, the inlet water valve should be opened first, followed by the heating steam inlet valve; when shutting down, the process should be reversed.

12. When operating the deaerator, if you find that steam is being discharged with water, you may handle the situation using the following methods:

Adjust the heating steam inlet valve

b. Inspect pressure adjustment device

c. Manual pressure reduction operation

d. Gradually close the secondary heating steam cutoff valve.

13. Test the dissolved oxygen content of the water in the sampling tank to ensure it meets the standard. If it does not, adjust the water inflow, air inflow, and exhaust flow to achieve compliance. Once qualified, you can supply water to the boiler.

14. Regularly test the oxygen content of the incoming and outgoing water at specified intervals, record the readings of various monitoring instruments, to ensure the normal operation of the deoxygenator.

15. Cautionary Notes

a. When the deaerator experiences severe vibration and water ejection, water hammer has occurred. Reduce the water inflow accordingly.

b. During operation, attention should be paid to ensure that the pressure within the deaerator does not drop sharply, and vacuum conditions must be avoided at all costs.

c. In case of a short-term shutdown, prevent the deaerator from forming a vacuum or becoming full of air. Gently open the bypass steam valve to introduce a small amount of steam, maintaining a heated state within the deaerator head, and expel a trace of steam from the air exhaust.

d. Oxygen removers should be inspected regularly to prevent nozzle clogging, packing corrosion or compaction, and instrumentation failure.

e. If the deaerator is out of service for an extended period, the water in the tank should be drained completely to prevent corrosion of the vessel.

Five. Oxygen Remover General Accessories

·Safety Valve---Installed on the water tank, it automatically opens to relieve pressure when the internal pressure of the equipment exceeds the allowable limit, serving as a safety protection function.

·Pressure Gauge---Installed at the top of the deaerator, monitoring the pressure inside the equipment.

Thermometer — Located at the bottom of the water tank, monitoring the water temperature inside.

· Butterfly valve --- Installed in the heating steam pipeline, the valve adjusts the flow of heating steam with the aid of an automatic regulator to maintain the pressure inside the deaerator within the rated range.

· Water-seal tube --- When the liquid level rises, the pressure difference exceeds the water column pressure, causing the balance to be disrupted, and the liquid flows out through the water seal. It also serves as a pressure relief function when the operating equipment's air pressure exceeds the safe limit.

·Stop valve—Installed on the topping-up pipe, it adjusts the flow of make-up water with the help of an electric water level control system to maintain the normal water level of the tank.

·Adjustable Valve --- Installed on the topping-up pipe, it regulates the flow rate of water supplied for topping-up using an electric water level control system to maintain the normal water level of the tank.

·Electrical Contact Level Monitoring --- Consists of a sampling electrode point, a level monitoring cylinder with electrical contacts (primary instrument), and a super-pure ceramic electrode and display (secondary instrument). Installed on a water tank, it monitors the water level inside and outputs a 4-20mA signal to the control room to regulate the water level valve.

· Magnetic Flip Level Gauges --- Installed on water tanks, they monitor the water level in situ and can also be connected remotely to output a 4-20mA signal to the control room for regulating the water level valve.

·Balanced Tank - Used in conjunction with pressure/differential pressure transmitters and level gauges, it can reflect the deaerator's (weight) water level during boiler startup, shutdown, and normal operation.

·Electric gate valve --- Installed on the water outlet pipeline of the water tank, when the water level in the tank exceeds a certain limit, the electric gate valve automatically opens with the help of the electric water level regulation system, and the excess water above the limit is drained into the overflow tank.

·Pressure Auto-Adjuster---Automatically adjusts the opening of the steam inlet valve, regulating steam flow while maintaining stable pressure within the deaerator.

· Electric Water Level Regulation System --- Automatically adjusts the flow of supply water and controls the limit water level drain valve (electric gate valve).

Section 6: Order Provision Data

1: Oxygen Dehydrator Output (T/H) and Effective Volume of Water Tank (m3).

2: Oxygen Remover Operating Pressure, Temperature...

3: Only replace the oxygen-depletion tower and provide the installation connection diagram for the original oxygen-depletion tower.

Section 7: Renovation

Our factory offers a complete supply of new-type water film deaerators and also undertakes改造 projects for power plants involving spray tray and spray packing deaerators. Specifically, this includes:

Low renovation costs, approximately half the price of replacing the deaerator head.

2. Fast progress, easy to process and on-site modification and installation. Utilize the original deaerator head's shell and cap, remove all the spray tray or spray packing components inside the original deaerator head, retain the lower steam inlet dish, and then install a liquid-gas mesh and a water grate at a certain position above the lower steam inlet dish. Finally, seal and secure it with a circular pressure plate to prevent water and steam short-circuiting during future operation.

3. After separating the junction between the head and the cylinder, weld and install them into the degassing unit. Connect the remaining pipeline components according to the provided modification plan, and the job is complete. Upon passing inspection, the unit is ready for operation.

4. During the modification process, the diameter of the deaerator head is generally not increased; instead, its height is appropriately adjusted according to specific circumstances, usually only raised or mounted at the original height.