how does a steam ejector vacuum system work

how does a steam ejector vacuum system work

The working principle of the steam ejector vacuum system is mainly based on the Venturi effect and the law of conservation of momentum. Here is a brief description of how it works:

• Steam supply: The system first introduces high-pressure steam through the steam supply pipe. These steams are usually superheated steam, with higher pressure and temperature.
• Injection process: High-pressure steam enters the nozzle part of the injector. Due to the contraction of the nozzle, the steam flow rate increases sharply and the pressure decreases. This high-speed steam flow creates a low-pressure area at the nozzle outlet.
• Suction effect: Due to the low pressure at the nozzle outlet, the surrounding air or other gases are sucked into the mixing chamber of the ejector. These inhaled gases mix with high-speed steam to form a gas-liquid mixture.
• Diffusion process: The mixture then enters the diffuser section, where the pipe gradually expands, the velocity of the mixture decreases, and the pressure rises. In this process, part of the kinetic energy is converted into pressure energy, and the gas in the mixture is further compressed
• Condensation and separation: After passing through the diffuser, the mixture enters the condenser, where the steam is condensed into water and the gas is separated. The condensed water can be discharged through the drainage system, while the separated gases are discharged from the system through the exhaust port.
• Vacuum generation: Through the process described above, the system continuously draws in and expels gas, thereby creating and maintaining a vacuum in the connected device or container.
• Circulation and adjustment: The entire process is carried out in a cycle. By adjusting the supply and pressure of steam, the vacuum degree and suction capacity of the system can be controlled.

It should be noted that the steam ejector vacuum system usually requires a certain amount of cooling water to condense the steam, and also produces noise and vibration. Therefore, these factors need to be considered in practical applications and corresponding measures must be taken to deal with them. In addition, the design and operation of the system also need to be adjusted and optimized according to specific application scenarios and needs.

What are the application scenarios of steam ejector vacuum systems?

Steam ejector vacuum systems have a wide range of application scenarios, including but not limited to the following:

1. Power plants: Captive thermal power plants often need to handle different levels of steam pressure in medium to large enterprises. The vacuum system of the steam ejector can increase the pumping or exhaust steam of the boiler new steam injection to the pressure that meets the user’s requirements by means of injection, so as to solve the problem that the steam supply pressure of the steam turbine is fixed and cannot meet the production needs.
2. Waste steam and waste heat recovery: Using the steam ejector vacuum system, the steam at lower pressure can be injected with steam at a higher pressure to obtain steam at a certain pressure in the middle, so as to achieve the purpose of low product and high consumption or waste heat utilization. In this way, exhaust steam can be recycled, less emptied, and thus steam consumption can be saved.
3. Condensate and flash steam recovery: The steam ejector vacuum system can also be used to recover and boost condensate and flash steam generated by steam heating in the production process.
4. Air pressurization, vacuuming, condensation, combustion, etc.: Steam ejector vacuum systems are also widely used in these areas. For example, it can pressurize compressed air to high pressure and then use it in spraying, sandblasting and other processes, which is more energy-efficient than traditional compressors; At the same time, it can also be used to extract gases in high vacuum environments or to condense water vapor into water.

Overall, steam ejector vacuum systems provide an effective solution for a wide range of industrial applications through their efficient steam processing and utilization capabilities, especially in terms of energy recovery, energy saving, and process optimization. However, it is important to note that the application of a steam ejector vacuum system needs to be designed and adapted to the specific scenario and needs to ensure optimal performance and efficiency.

What are the advantages and disadvantages of the steam ejector vacuum system?

Steam ejector vacuum systems have a range of advantages and disadvantages, each of which is outlined below:

Merit:

1. Increase the vacuum of the unitThe vacuum system of the steam ejector can effectively improve the vacuum of the unit, so that the vacuum value of the unit under the same working conditions is better than that of the unmodified vacuum system. Especially in the summer working conditions, the transformation effect is more obvious
2. Save electricity and reduce consumption: The energy savings of this system are remarkable. It can be full by means of a three-stage steam jet pump
3. Low maintenance, safe and reliable operationThe vacuum system of the steam ejector is simple in structure, mainly composed of nozzles and heat exchangers, without rotating equipment and without using motors, so the operation is stable, safe and reliable, and the maintenance workload is small.
4. High return on investmentWhen retrofitted according to the design, the system can bring significant economic benefits, usually paying for itself within a short period of time after the investment.

Shortcoming:

1. Steam efficiency is low: The steam efficiency of the steam ejector vacuum system is relatively low, and the steam consumption is large. Therefore, the system is mainly suitable for occasions with low absolute pressure requirements to ensure its warping
2. Slow startupSince the pumping volume of the jet pump is certain, at the beginning of the system start-up, the vacuum level is increased slowly due to the high pressure. This is slower to start compared to other types such as reciprocating pumps, water ring pumps.
3. Gas recovery is difficult: After the inhaled gas is mixed with the steam, the recovery process is relatively difficult and may require additional treatment steps.
4. Nozzles are susceptible to corrosion and wear: After prolonged use, nozzle pipes are susceptible to corrosion and wear, which can affect the performance and efficiency of the system and require regular maintenance and replacement.

In summary, the steam ejector vacuum system has significant advantages in improving the vacuum of the unit, saving electricity and reducing consumption, but there are also some limitations in steam efficiency, start-up speed and gas recovery. When selecting and applying the system, there are trade-offs and considerations that need to be made according to the specific application scenarios and needs.