The field of FGD
Yantai Sunnyhexing Environment Protection Equipment Co., Ltd.
The field of FGD
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Vacuum Belt Dehydrator
Product number:K005
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Vacuum Belt Dehydrator
Vacuum belt dehydration is also known as the fixed vacuum rubber belt filtration; Our company develops a new and efficient solid-liquid separation mechanical device which can operate continuously. At the same time it is also a kind of mechanical device which can achieve solid-liquid separation taking advantage of material gravity and vacuum suction; In structure ,vacuum region lays out along the horizontal direction, and different technological process such as filtration, washing and drying can be finished taking advantage of the length of vacuum region. It has the advantages of high filtration efficiency, large production capacity, good washing effect, wide application scope, easy operation, stable operating, convenient maintenance and so on; It is especially suitable for suspension pulps which have coarse filtration solid particle, high density and whose cake in need of many times washing .It can be widely applied in metallurgy, mine, chemical industry, paper making, food, pharmacy, environmental protection and other industries' solid-liquid separation; It has great applications especially in the gypsum dehydration of wet flue gas desulfurization (FGD).

Vacuum box lifting device
Vacuum box can have lifting through swinging leg configuration, which is convenient to change friction belt. And it is fixed on the rack by bolts. Besides, there is friction belt and perforated rubber belt on it.

Tension device
Rubber belt tension device adjusts the tensity of rubber belt through lead screw in order to guarantee enough friction of rubber belt and avoid deviation of rubber belt while operating.

Rectification device
The deviation of filter cloth is rectified by pushing the rectification roller swing with airbag to deviate a certain angle. The airbag and controlled components are imported products and they have stable reliability.

Filter cloth cleaning device
Filter cloth and rubber belt are cleaned by means of spraying the process water .Furthermore, the sealed tank with vacuum suction is provided, which ensure the normal operation of belt conveyor and clean job site; nozzle spray products is usually made by American Spraying Systems Inc, which can fully guarantee the cleaning effect.

Rubber belt supporting device
Supporting device on the rubber belt uses the tightness of the roller support , angle iron support frame fitted with rubber belt on both sides of the filter surface, and steel alloy roller lays out onthe bracket averagely ,besides, rubber belt running on the roller can reduce rubber belt abrasion and drive resistance, while the service life of the rubber belt can also be extended.

The ideal combination between long-distance control system and long-distance DCS control system is convenient to operate the device and manage the program.

Dcs control system:

1.frequency converter, proximity switch, limit switch, thickness gauge and other control systems are adopted.
2.It can realize control for system deviation, extreme position of rubber belt(shutdown, node signal output),filter cloth tensile failure(shutdown, node signal output).
3. Long-distance and start-up, shut-down on-site according to material thickness adjust automatically main controlled motor rotating speed and output to the communication interface of the DCS system.
4.The control system components adopt imported parts from abroad and domestic famous brand products, and it has stable reliability. It is safe and stable to use system control.

Flow monitoring control in a vacuum and sealing water pipeline, the slider lubricating water pipeline, the vacuum pump working fluid inlet piping, filter cloth rinse water pipeline are equipped with the flowrate switch monitoring low flowrate alarming, and at the same time ,electromagnetic flowmeter is installed on the cake leaching pipeline , which is helpful to control the flowrate directly for DCS systems.

Equipped with a pull rope switch on the emergency stop switch. When the crisis situation occurs, the operators can immediately pull rope on the emergency switch to make the device stop running, so as to ensure the safety of the surrounding personnel and equipment.

The cake thickness measurement system is also equipped with ultrasonic thickness gauge, and it can output 4 ~ 20mA analog signals to the DCS system according to the thickness of the materials .At last, DCS system will adjust the frequency of inverter based on the feedback current, to control the operating speed of the drive motor.

The device is equipped with limit switches for collecting filter cloth deviation limit and rubber belt deviation limit. Once the deviation limit range is exceeded, contact signaling will be sent to DCS system, and the whole system will stop immediately; Normally, there is small-scale swinging phenomenon of filter cloth and the device has its own automatic rectification device.


Vacuum Pump
Vacuum pump injects process water into the cavity taking advantage of the working style of water-ring. At the same time, it forms -0.05-0MPa vacuum pressure with the rotation of the impeller, and it is the vacuum source of the whole device.

Gypsum hydrocyclone slurry comes into the inlet of hydrocyclone through pumps, and hydrocyclone adopts the device which is imported with original packaging. The slurry concentration can increase from 20% to 40% -50% by hydrocyclone concentration, greatly improving processing capabilities of the vacuum belt dehydration .

Filter cake flushing tank
The discharging outlet of filter cloth rinsing water is connected with the inlet of filter cake flushing tank. And supplementary feed valve adopts inlet floating ball valve which can supplement water automatically .Drain valve and low level liquid alarming switch are equipped, which can protect filter cake washing water pump and pipe automatically.

Filter cloth flushing tank. Filter cloth flushing tank adopts carbon steel lined with carbon steel or made by PPR .The steam-water separator filtrate outlet of vacuum pumps is connected with the intake of filter cloth flushing tank , and the supplementary feed valve adopts floating ball valve imported from Germany, which can supplement process water automatically. Besides, it is equipped with low liquid level alarming switch, which can achieve the automatic protection of filter cloth washing water pump.

The working principle:
Water and other liquids can be separated from the slurry. The gypsum slurry after primary cyclone dehydration comes into the feed box of the dehydrator in the FGD process. At the feed side, the gas is removed by vapour hood, and the slurry was evenly distributed to the moving cloth and drainage belt region. The filter cake moves over the drainage belt and has a dehydration through the vacuum negative pressure. The vacuum is generated by the vacuum box under the drainage belt. The filter cake rinses from the top of the cake washing tube when moving along the direction of the length of dehydrator. When the cake moves to the discharging side of the vacuum belt conveyor, gypsum slurry has become the output product, of which moisture content <10%. The filter cloth separates from the dewatering belt and comes into the next cycle after rinsing.

Process Flow Diagram

The features of vacuum belt dehydrator:
●There is a circular friction belt between the vacuum box and the filtration rubber belt with the water seal, lubrication and reliable cooling vacuum sealing. And it can maintain a steady fidelity, reduce the water content of filter cake and it is favorable to the stable operation process conditions. The friction of annular friction belt is small, besides, it has a long service life, and it is easy and convenience to replace.
●The rubber belt adopts the air cushion supporting or water film pad supporting or encryption roller supporting. And it operates floating on the supporting pad , reducing the running resistance, which can help prolong the service life of the rubber belt.
●Adopting annular filtration rubber belt, which has strong tensile strength and long service life.
●The integral structure adopts modular design, which has flexibility to assemble and is convenient to transport and install.
●It is equipped with airbag filter cloth automatic rectification device, and the filter cloth can be ensured to have a steady operation.
●The automatic drainage separation device or liquid-column drainage separation device under the vacuum equilibrium state can achieve zero error automatically drainage of the vacuum belt dehydrator or high dislocation drainage in order to satisfy the application requirement of various conditions.
●The control system applies PLC control technology and takes full account of the interface technology design with the remote DCS control; And it can achieve the PID adjustment, on-site and remote automatic control of the device operating.