Electric precipitator

Types of Electric Precipitators

An industrial electrostatic electric precipitator serves as an air pollution control device to remove particulate matter from flue gases emitted by industrial processes. In an electrostatic precipitator, charged particles are separated from neutral ones, and oppositely charged electrodes attract them. The following are the two main types of electric precipitators:

• Wet Electrostatic Precipitator

  An industrial electrostatic wet precipitator removes particulate matter by spraying charged water on the oppositely charged particles, thereby neutralizing them, which can include very small particles such as sulfuric acid formed through condensate water. It operates like a washing machine for flue gas. It scrubs the gas, collecting all particulate matter in the wash water. This technology has been around since the 1960s and has proven to be successful, for example in reducing acid rain. It is especially effective at removing small dust particles by liquid or water. Not only does it remove 80% of the particles, but it also takes out heavy metal particles and radioactive particles. One major benefit of a wet electrostatic precipitator is that it can handle gas flows with high humidity and even get rid of chemosorbed particles, which are particles that stick to others. Even though the cleaning solution gets dirty, the machine can clean itself with a washing process on a regular basis. Sometimes, reusable cleaning solutions are stored in tanks to reduce costs.

• Dry Electrostatic Precipitator

  Dry electrostatic precipitators are the more common type used in industries today. They are simpler and rely on a high DC voltage (between 30 and 100 kV) to charge dust particles that pass through the gas flow. The charged fine dust particles are electronically collected on oppositely charged plates which require grounding. The dust is then removed from the plates by vibrating them, and the dust falls into hoppers or containers, where it can be disposed of or recycled. Dry electrostatic precipitators function efficiently even when the temperature is low and humidity is high by using non-thermal corona discharge at room temperature. Remarkably, they can achieve removal efficiencies of up to 99%.

Specifications and maintenance of electric precipitators

Specifications

• Flue gas flow capacity: The gas flow rate that the electric precipitator can handle is usually measured in cubic meters per hour (m3/h) or liters per minute (lpm).
• Collection efficiency: The collection efficiency represents the percentage of particles removed by the electric precipitator, which may be specified as a typical numerical value or a range.
• Remediation methods: The electric precipitator may provide different remediation methods, such as manual cleaning, automatic cleaning, or external centralized remediation facilities.
• Operating temperature range: The operating temperature range at which the electric precipitator can operate normally, which is usually measured in degrees Celsius (°C) or Fahrenheit (°F).
• Power requirements: The power requirements, including voltage and current, are possible to use in industrial and commercial environments.
• Dimensions and weight: Dimensions and weight: The size and weight of the equipment help determine its installation space and portability.
• Applicable industries: The electric precipitator may be adaptable to different industries, such as power generation, cement, metallurgy, chemical industry, etc.
• Applicable particle sizes: The electric precipitator may be designed to be suitable for different particle sizes, such as fine particles, coarse particles, etc.
• Electrode types: The electric electrodes used in the electric precipitator include plate electrodes, wire electrodes, and other special electrode types that may differ in shape and configuration.

Maintenance

Regular maintenance can ensure the proper functioning, stability, and long-term performance of electric precipitators while reducing abnormal equipment stoppage, unnecessary maintenance costs, and accident risks.

• Check: Regularly inspect the overall equipment to check for loose, damaged, or worn parts about the body, electrode frames, insulators, etc.
• Cleaning: Clean the precipitator body, electrode frames, and other parts to remove dust, grease, and other contaminants, ensuring that the heat dissipation and insulation performance of the equipment are not affected.
• Replacement of consumables: Replacement of related consumables, such as cleaning brushes, cleaning fluids, etc., to ensure the effectiveness and efficiency of the cleaning process.
• Lubrication: Lubricate the moving parts, such as bearings, gears, etc., ensuring smooth operation and reducing abrasion.
• Inspection of electrical components: Inspect and clean the electrical components, including terminals, relays, etc., to ensure good electrical connections and stable contact.
• Calibrating parameters: Periodically calibrate and adjust the relevant parameters of the equipment according to the usage needs, such as voltage, current, etc.
• Replacement of filters: If the equipment is fitted with a filter, it should be replaced at regular intervals to ensure the quality and purity of the filtered power supply.
• Maintenance of ventilation systems: Maintain and clean the ventilation system, including fans, ducts, etc., maintaining proper air circulation and heat dissipation.

Usage scenarios of electric precipitators

Industrial electrostatic precipitators are critical components in various industries that need to control air pollution and protect both human health and the environment. Here are some industries using electric precipitators:

• Power generation

  APower plants, particularly those using fossil fuels such as coal, oil or natural gas, generate a significant number of ash particulates during combustion. This can cause serious environmental issues. Therefore, many power plants utilize electrostatic precipitators in exhaust systems to remove these ash particles and pollutants before they are released into the atmosphere, thus complying with emission regulations. Additionally, the proper disposal of ash collected by the precipitators can also aid in power plants' management of ash disposal systems.

• Cement production

  Cement manufacturing involves handling raw materials and high-temperature processes that generate considerable amounts of dust. Dust control has sought to protect workplaces, downstream production, and the environment. Thus, the cement industry has adopted electrostatic filters to remove dust from kiln and mill gases, maintaining safe cement quality and compliance with environmental regulations.

• Metallurgy and steel production

  The metallurgical and steelmaking processes release a large quantity of flue gas dust and heavy metal particulates, which pose a significant threat to both air quality and human health. An electrostatic filter is used to remove such flue gas dust, thus improving air quality and creating a healthier living environment.

• Oil and gas

  Industries related to oil extraction, gas production, and refining operations may discharge gas containing acid mist, such as sulfuric acid mist, posing a danger to both air quality and public health. Electrostatic separators are to be employed to extract acid mists from the gas, thus ensuring compliance with environmental regulations and improving air quality.

• Food and beverage

  Food and beverage processing lines often use oil and fat, which may splatter onto production lines and the air, thereby creating a fire hazard. Electrostatic filters are applied to remove oily fumes from the air, thus preventing the occurrence of fire hazards and ensuring the safety of food and beverage production.

• Hospital and healthcare equipment

  Healthcare facilities such as hospitals must meet high standards of air quality to prevent the spread of infections and ensure patient safety. Therefore, air electrostatic filters can be utilized to remove pathogens, including bacteria and viruses, from the air, thus improving air quality and reducing the risk of hospital-acquired infections.

These are but a few instances many other businesses that utilize electrostatic precipitators. As environmental concerns grow, the scope of applications for electric precipitators is bound to increase, too.

How to choose electric precipitators

• Industry needs assessment

  The types of industries that utilize electric precipitators generally have high requirements for air pollution control. Therefore, buyers can first assess their industry needs. For example, if they are in the power generation or metallurgy industries, they might have to deal with large quantities of flue gas. In such cases, they will need a more robust and efficient electric precipitator, possibly a multi-field one, to ensure compliance with environmental standards.

• Explicit treatment objectives

  When choosing an electric precipitator, it is necessary to clarify the pollutant types and treatment demands. For instance, if the focus is on fine particulate matters such as PM2.5 and soot, selecting an electric precipitator with a higher removal efficiency for these specific particles is crucial.

• Site suitability

  Buyers also need to consider whether the selected electric precipitator is suitable for their installation environment. For example, an electric precipitator designed for open-air installation might not be appropriate for an indoor location, and vice versa. Moreover, its dimensions should match the buyer's setup space to ensure smooth implementation.

• Cost-effectiveness

  Buyers must consider the cost-performance ratio of the equipment and its long-term operating expenses. For example, a more expensive model might provide greater stability, and its automatic control system could lower labor costs, resulting in better cost-effectiveness in the long run.

• Supplier selection

  When choosing an electric precipitator, buyers should select reputable manufacturers. They can research the manufacturer's market standing, product ranges, and after-sales services to ensure they receive in-depth support and services throughout the equipment's life cycle.

Electric precipitator FAQ

Q1: What is the difference between an electric and gravity precipitator?

A1: An electrostatic precipitator differs from a gravity version since it employs electric forces to remove particles. Electrostatic forces are more efficient than gravitational forces at separating particles, particularly fine ones.

Q2: Do precipitators discharge current?

A2: The electric precipitator collects charged particles. However, it does not permit current discharge or flow like a resistor.

Q3: Are electric precipitators safe?

A3: Safety concerns may arise due to high-voltage electricity usage. Nonetheless, well-designed and properly-maintained precipitators can be safe. Manufacturers typically enclose and ground the equipment components. Operators can also switch-off the precipitator during maintenance to enhance safety.

Q4: Do electric precipitators consume lots of power?

A4: Electrostatic precipitators consume some power due to high-voltage power supplies. Nonetheless, the power consumption is usually lower than that of other air pollution control devices. Their power consumption may be justified by the device's efficiency and the resultant savings and benefits.