Lime Hydrator is the most essential part of a lime hydration plant(also called hydrated lime plant). It is an agitated chamber for quicklime(CaO) and water to fully react at a pricisely controlled ratio to produce dry hydrated lime powder(also called calcium hydroxide). The reaction process is called lime hydration.

DynNor Lime Hydrators GXH-10/15/20:

Depending on the capacity and stage of hydration, GXH lime hydrators are designed with 2 to 4 mixing shafts, each installed with unique profile of mixing blades and at an optimal angle to improve performance. All the blades are made of high wear resistant alloy steel to increase campaign life.

The first-stage hydrator is installed water ejection system, VFD motor to adjust rotation speed for more flexible operation. Its primary purpose is to achieve fast and effective mixing of lime with water.

The second (or third in case of 4-stage hydration) stage hydrator is for additional mixing and complete reaction of water and lime. All the hydrators installed with VFD motors.

The last stage hydrator is primary for homogenization. Depending on the layout, the dimensions of this hydrator can be quite different. For vertical stack layout, this hydrator is wider to allow additional space to install the integrated pulse bag filter.

Integrated Bag Filter System: lime hydration process generates a lot of steam along with dust due to the exothermic reaction, this needs to filtered for environmental reasons. The common approach now is to install pulse jet bag filters to filter the dust steam and return the captured lime particles back to the hydrator. DynNor pulse jet bag filter system can meet the most stringent environmental regulations in EU countries.

--Typical Lime Hydration Plant Layouts

Major Equipment in a typical lime hydration plant(Hydrated Lime Plant):

Lime crusher: Its primary goal is to reduce quicklime size to below 30mm or 10mm depending on the process selected for more efficient hydration. In case of lime size less than 30mm or 10mm, crusher will not be required.

Quicklime &water batching system: Our lime hydration system is installed with high accuracy lime feeding scale (belt type or screw type) and inverter controlled water pump along with electromagnetic flowmeter to provide well balanced formular for reaction.

Lime Hydrators: this is where the quicklime is converted to hydrated lime powder with right amount of water. The reaction equation is: CaO + H2O = Ca(OH)2 + 66.1kJ of heat(for 1 mol of CaO). Based on the atomic weight of the formula, 1Kg of CaO and 0.32Kg of water will produce 1.32Kg of Ca(OH)2 in perfect condition. In reality, the numbers will be quite different depending on the quality of quicklime.

Conveyors: Mechanical conveyor (bucket elevator/screw conveyor) or pneumatic conveyors to transport quicklime and hydrated lime between each of the process.

Silos: for storage of quicklime and hydrated lime.

Control system: centralized PLC control to reduce operation workload, generates daily production reports for analysis and improvement.

Additional systems: The non-hydratable rejects from powder separator or hydrator can be used as building lime after grinding. For this purpose, Raymond mill, roller mill, impact mill or ball mill system can be considered depending on the selected process.

Applications of Hydrated Lime /Ca(OH)2:

Wastewater Treatment, pH regulation (post and pre-treatment),sugar plants, gold leaching plants

Flue gas desulfurization(FGD),Sulfur Dioxide (SO2) Removal, Hydrochloric Acid (HCl) Removal

Food additives：Ca(OH)2 has highly activity and loose structure, it is popularly added as food additives.

Medical areas:

Construction &painting materials: this is one of traditional uses for Ca(OH)2 due to its reaction with CO2 for form CaCO3