Dust Removal System
Category:
产品列表
Release time:
2018-11-14
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1. The dust removal system includes: electric furnace dust collection hood, branch pipes, automatic air volume control valve, main air duct, spark arrester, dust collector (ash discharge), induced draft fan, silencer, and exhaust pipe. It combines the advantages of compartmental back-blowing and pulse jet cleaning dust collectors, thereby expanding its application range and extending the service life of filter bags. It is a highly efficient, economical, reliable, high-capacity, and user-friendly dust removal equipment. It is a mature and advanced bag-type dust collector structure widely promoted both domestically and internationally. This dust collector has excellent cleaning performance; under the same jet pressure conditions, it can operate at a higher filtration air velocity compared to other pulse dust collectors while ensuring high dust removal efficiency. The dust collector has a compact and reasonable structure, uses an external filter method for the filter bags, does not require entry into the dust collector for bag replacement, making the operation convenient with less dust exposure and maintenance workload. The pulse valve has a simple, novel structure with low resistance and excellent cleaning effect.
f1. Dust collection device: The electric furnace uses a cyclone-type dust hood.
f2. Air volume calculation: The total air volume design for the dust removal system of 2 units of 3T electric furnaces is 20,000 m³/h; the maximum air volume during electric furnace melting is during tapping and spheroidization, while during charging only 60% is needed, during melting only 40%, and during holding only within 30%. Electric air valves are installed to adjust the suction air volume by regulating the valve opening according to the working status of each furnace.
f3. For the electric furnace situation, the melting department designs a dust collection and removal system using a two-stage dust collection method. Since a small amount of sparks may mix into the dust during charging, tapping, and front furnace molten iron spheroidization, a spark arrester is installed. The primary dust collector is a spark arrester cyclone dust collector, and the secondary dust collector is an offline cleaning pulse bag dust collector with an air box.
f4. The electric furnace melting flue gas is collected by the furnace cover dust hood, and the front furnace molten iron spheroidization uses a side suction hood (optional). The system is interlocked with the electric furnace working status, adjusting the suction air volume accordingly to vary the fan output via frequency conversion. The entire dust removal system is controlled by PLC, executed through electric air valves and frequency converters to achieve energy saving.
f5. Duct layout: Branch pipes converge into the main air duct. According to drawings and site conditions, the main air duct is planned to be laid in the trench, and after exiting the workshop, it connects to the outdoor part of the dust collector room. The trench piping and dust collector foundation construction are the responsibility of the user.
f6. Working status selection valves: Each dust collection hood uses electric valves connected to the air ducts, allowing the computer to adjust the valve opening according to the required air volume for the working status to regulate airflow and achieve energy-saving operation.
f7. Main air duct specifications and routing: The main air duct for electric furnace dust removal is divided into three sections based on air volume. The nearest section diameter is 600mm; the middle section is 700mm; the far section (connecting to the dust collector) is 600mm in diameter. The duct runs from the trench to the left side of the workshop and connects to the main outdoor dust collector.
f8. Dust collector layout: The primary dust collector has a spark arrester function. The principle is to use the inertia of sparks to collide with a rotating wheel or grid and inner wall guide strips to extinguish and stop them, causing them to fall into the cyclone dust collector ash hopper. This protects the downstream bag dust collector from being damaged or bags being burned or stuck. The cyclone dust collector uses downward swirling airflow, causing particles larger than 10 microns to fall into the ash hopper by gravity, while the remaining airflow exits through the central duct and enters the bag dust collector.
Installing a cyclone dust collector can reduce the load on the downstream bag dust collector, improve filtration efficiency, and extend the service life of the filter bags.
f9. Dust collector air temperature limit protection: A temperature measurement device is installed at the cyclone dust collector outlet to promptly detect the air temperature entering the bag dust collector. When the temperature exceeds 120°C, the PLC control immediately opens the electric fresh air valve installed near the bag dust collector inlet, introducing ambient air to quickly lower the air temperature entering the bag dust collector, thus preventing filter bag aging or burning and sticking caused by high temperature.
2. Bag dust collector:
1) Design and selection:
This design scheme selects the internationally recommended and currently most effective compartmental offline cleaning high-pressure pulse bag dust collector. This dust collector has excellent cleaning performance; under the same jet pressure conditions, it can operate at a higher filtration air velocity compared to other pulse dust collectors while ensuring high dust removal efficiency. The dust collector has a compact and reasonable structure, uses an external filter method for the filter bags, does not require entry into the dust collector for bag replacement, making the operation convenient with less dust exposure and maintenance workload. The pulse valve has a simple, novel structure with low resistance and excellent cleaning effect.
2) Structure and working principle are as follows:
Electric furnace melting dust → dust collection hood → branch pipe → main air duct → spark arrester → cyclone dust collector (ash discharge) → bag dust collector (ash discharge) → induced draft fan → silencer → exhaust pipe → clean gas discharge.
The air box pulse bag dust collector consists of an ash hopper, middle box, upper box, inlet and outlet ducts, filter bags and frames, jet device, discharge mechanism, and electrical control system. The middle box is divided into compartments or groups. During operation, dust-laden gas enters the ash hopper via the dust collection pipe; coarse dust particles fall directly to the bottom of the ash hopper, while fine dust particles follow the airflow turning upward into the middle box. Dust accumulates on the outer surface of the filter bags, and filtered gas enters the clean gas collection pipe and is discharged to the atmosphere via the fan. The filtration chamber is equipped with differential pressure detection; when pressure exceeds 1500 Pa, it automatically initiates the cleaning program. Timed and manual cleaning functions are also provided. The cleaning process first cuts off the clean gas outlet channel of the compartment or group, placing the filter bags in a no-airflow state, then opens the pulse valve to use compressed air for pulse jet cleaning. The cut-off valve remains closed long enough to ensure that dust detached from the filter bag surface settles into the ash hopper, preventing dust from reattaching to adjacent filter bags and ensuring thorough cleaning. A programmable control cabinet fully automates the control of cut-off valves, pulse valves, and ash discharge valves. Dust in the ash hopper is discharged via the ash discharge valve. Each pulse jet lasts 0.1 seconds, after which the filter bags resume filtration. The cleaning program proceeds to the next compartment or group sequentially.
3) Main Features:
1) The offline ash cleaning air box pulse bag dust collector is a high-efficiency bag dust collector that combines the advantages of compartment reverse blowing and pulse jet cleaning dust collectors. It overcomes the shortcomings of insufficient cleaning intensity in compartment reverse blowing and the simultaneous filtering and cleaning in pulse jet cleaning, thereby expanding its application range and extending the service life of filter bags. It is an efficient, economical, reliable, high-capacity, and user-friendly dust removal equipment. It is a mature and advanced bag dust collector structure widely promoted both domestically and internationally.
2) Filter material is the core of the bag dust collector. Our dust collector filter bags use Jiangsu Dongfang filter bags (or optionally Sino-American joint venture Bidafu, more expensive) medium-temperature water-repellent and oil-resistant diaphragm polyester needle felt, with an operating temperature within 120°C and instantaneous temperature within 150°C; these are high-strength, low-elongation filter bags suitable for steel, casting, and metallurgical dust filtration. The filtration speed can reach 0.8 to 1.5 m/min. To achieve a 50 mg/m3 effect, a filtration speed of about 1.2 m/min is selected.
3) Reliable and Practical: This dust collector has the highest operational reliability, significantly reducing maintenance work and costs, thereby improving the overall system economy.
4) High Dust Removal Efficiency: For gases with dust concentration ≤15g/Nm3, the dust removal efficiency can reach over 99.5%.
5) Easy Operation and Maintenance: The filter bag mouth uses an elastic expanding ring that can be directly embedded on the tube sheet, ensuring both sealing and easy disassembly, reducing maintenance personnel's contact with dirty bags.
6) Energy Saving: The control system can be connected with the feeding vehicle, electric furnace melting furnace control system, and ladle operation platform. Through PLC control and frequency conversion adjustment, the system's processing air volume can be automatically adjusted in real-time according to the melting furnace and ladle working status, reducing unnecessary energy consumption. The energy-saving effect is significant, reaching up to 30%.
7) Thorough Ash Cleaning: The offline ash cleaning method provides stronger cleaning force and thoroughness, avoiding re-adhesion of dust. The streamlined compressed air pipeline design reduces pressure loss before cleaning while focusing on improving cleaning uniformity.
8) Uniform Airflow Organization: Uniform airflow organization is very important for bag dust collectors. Our bag dust collector adopts a co-current and counter-current method. The reasonable structure and uniform airflow organization can significantly improve the scouring of local areas of the equipment, which is a major factor in short filter bag life and equipment wear.
9) High Degree of Automation: Uses Siemens PLC full intelligent control with complete functions and strong reliability. The operation panel uses a touchscreen with a user-friendly, intuitive, and easy-to-understand human-machine interface. The automation level is high, with fan frequency conversion speed regulation. The air volume is automatically adjusted according to the combined working status of each electric furnace, achieving high efficiency and energy saving.
a. The product is equipped with a dust collector PLC control cabinet, touchscreen, and power cabinet.
b. Air requirements for the jet system: Compressed air source is connected to a dedicated air storage tank for the dust collector, with oil removal and dehydration treatment. After pressure reduction by a pressure reducing valve, clean air is supplied to the dust collector.
c. Flue gas temperature control: To protect the filter bags and extend their service life, the flue gas temperature entering the dust collector must not exceed 120°C. Therefore, a fresh air valve is installed between the cyclone dust collector and the bag dust collector. When the flue gas temperature is too high, the fresh air valve opens, mixing cold air into the pipeline to control the flue gas temperature entering the bag dust collector.
d. Ash discharge and ash conveying device: The ash discharge device uses a screw feeder or a star-shaped partition feeder for ash discharge, ensuring effective dust discharge and preventing system air leakage during ash discharge.
Keyword:
Automatic pouring system
Automatic Feeding System
Automatic pouring system
Automatic Feeding System
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