Fluidized Roasting Device-BAOLAN EP INC.

Incinerator: Fluidized Roasting Device

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Waste Gas Treatment: DeSOx

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Product Details

Fluidized Roasting Device

Technology Introduction

The fluidized roasting device is a new type of high-efficiency and energy-saving ro asting device developed by Baolan EP Inc. under the "dual carbon" goals. The basic principle of the device is to use fluidized suspension technology, allowing gases and solids involved in reaction heat and mass transfer to be in a fluid and dynamic state, achieving the fastest mass transfer, heat transfer, and speed, and maximizing energy efficiency.

The fluidized roasting device is a new type of high-efficiency and energy-saving ro asting device developed by Baolan EP Inc. under the "dual carbon" goals. The basic principle of the device is to use fluidized suspension technology, allowing gases and solids involved in reaction heat and mass transfer to be in a fluid and dynamic state, achieving the fastest mass transfer, heat transfer, and speed, and maximizing energy efficiency.

"Fluidized suspension" involves crushing and grinding the processed solids into fine powder, increasing the contact area between the solid and gas, and shortening the transfer and reaction distance within the particles. The gas flowing from bottom to top through these powders, upon reaching a certain speed, will suspend the solid particles, causing them to move continuously, similar to a fluid, hence the term fluidized suspension.

A batch of solid particles is placed on a porous distribution plate to form a bed layer, allowing fluid to flow upward through the bed layer. Due to the flow of the fluid and its friction with the particle surfaces, there is a pressure drop as the fluid passes through the bed layer. When the apparent flow rate of the fluid through the bed layer (calculated based on the cross-sectional area of the bed layer) is low, the particles remain stationary and in contact with each other; this type of bed is called a fixed bed.

When the apparent flow rate increases to the initial suspension velocity, the pressure drop across the bed equals the buoyant weight of the particles per unit area of the distribution plate (the weight of the particles minus the weight of the fluid volume they displace). At this point, the particles no longer support each other and begin to suspend in the fluid. As the apparent flow rate is further increased, the bed expands, the pressure drop across the bed remains nearly unchanged, but the movement of particles within the bed intensifies. This stage of the bed is known as the fluidized bed.

When the apparent flow rate increases to equal the free settling velocity of the particles, all particles are carried away by the fluid, and the fluidized suspension process enters the transport stage.

Process Flow Introduction

1. Material Drying

The production materials are transported into the raw material silo by a conveyor, and then fed into a Venturi mixer by a screw feeder where they fully mix with high-temperature flue gas. After entering a high-efficiency material separator for separation, the materials mix and dry with the hot flue gas exiting from the secondary preheater. The materials then move into the primary preheater, where the separated materials fully mix and dry with the hot flue gas exiting from the roasting separator. Finally, the materials enter the secondary preheater to complete the drying process.

2. Material Collection

The hot flue gas carries the dried materials, forming a dust-laden gas stream. This stream first passes through a preheating filter for mechanical dust collection, where most of the entrained solid materials are collected. The remaining dust-laden gas then enters a high-efficiency alloy purifier, completing the purification of the gas and achieving material collection.

3. Material Roasting

Materials collected from the high-efficiency alloy purifier and preheating filter are transported through pipes and, together with materials preheated by the secondary material preheater, enter the fluidized suspension roasting furnace for high-temperature roasting. After roasting, the materials enter the roasting separator with the hot gas flow, where the production materials are separated.

4. Material Cooling

After roasting, the materials sequentially enter the primary cooler, secondary cooler, tertiary cooler, and quaternary cooler for temperature reduction and cooling. They then proceed to the cooling bed, where air cooling and circulating water cooling reduce the temperature of the materials to 80-100°C, completing the entire process of material roasting.

System Introduction

1. Fluidized Suspension Roasting Furnace

The Fluidized Suspension Roasting Furnace utilizes high-temperature hot gases to induce a suspended fluidized motion in the materials on the fluidized bed. The roasting process for the materials is completed in a continuous suspended fluidized state.

1. The core part of the roasting system consists of a fluidized suspension roasting furnace and preheater. Fuel is injected from the bottom of the roasting furnace, providing heat. The heat carried by the roasted products is cooled and recovered in the preheater by primary air. The heat carried by the airflow in the preheater is used to preheat and dry materials in the preheating drying section and partially dehydrate the crystallized materials, thus recovering heat and reducing energy consumption.

2. Due to the continuous circulation of a large amount of solid materials, carrying a significant amount of heat, the roasting temperature remains uniform. Even in the event of temporary fluctuations in material supply or fuel supply, the temperature in the roasting furnace and preheater remains uniform and stable. The furnace temperature is typically controlled between 850-1250°C.

3. The entire system operates under positive and negative pressure, with air supply provided by a Roots blower. The advantage of this blower is that the air supply volume does not vary with system pressure fluctuations. Even if there are brief abnormal fluctuations in the furnace, the air supply volume remains stable. Roasting temperature is regulated by increasing or decreasing the material feed rate or fuel injection rate to produce the desired quality of product. The roasting furnace has a wide adjustment range, adjustable between 40% and 100%. When production is reduced, the combustion air volume is also reduced, maintaining a low excess air coefficient and thus keeping energy consumption low.

4. The roasting furnace is compactly configured, effectively utilizing space and reducing the footprint by more than 50% compared to a rotary kiln. Its steel structure frame is lighter than other furnace types, and its unit investment is lower than that of a rotary kiln. Due to the lower roasting temperature compared to a rotary kiln, the thermal shock on the inner lining is minimal, resulting in a lifespan of up to 10 years and maintenance costs about 50% of those for a rotary kiln.

2. Cooling Bed

The hot materials coming out of the roasting furnace need to be cooled to recover heat. A better way is to use air or cooling water to operate the cooling bed. The heated air can then be used as combustion air for the roasting furnace.

3. Preheating and Cooling System

The preheating and cooling system mainly consists of multi-stage separators before and after the fluidized suspension roasting furnace. The working process of this system is accomplished through the coordinated cooperation of these multi-stage separators. The preheating and cooling are achieved by blowing air to heat or cool the (raw) materials.

Application