BPG type closed-loop circulation spray dryer

The closed-loop circulation spray dryer is a dedicated equipment for drying organic solvent-based slurry. This unit uses nitrogen (or other inert gases) as the drying circulation gas. During the drying process, the material can be prevented from oxidation, and at the same time, organic solvents can be recycled. Closed-cycle spray dryers are generally used for powder drying of slurry prepared with organic solvents such as ethanol, acetone, and hexane. The equipment adopts explosion-proof design, and the drying process is safe and environmentally friendly. This equipment is suitable for the drying process where oxidation needs to be prevented and the consistency of the dried powder is required to be high. Powders from industries such as pharmaceuticals, chemicals, food, and lithium battery materials. Powder with an average particle size of 10-100μm can be obtained through centrifugal spraying. Of course, the entire drying process is completed under nitrogen protection, and organic solvents can be recovered simultaneously.

The working principle of closed-loop circulation spray dryer

Closed-loop inert gas spray drying project - closed-loop air flow spray drying unit, is mainly composed of nitrogen closed-loop circulation system, air flow spray dryer, solid-gas separation, nitrogen reverse blowing dust removal, condensation cooling solvent recovery, steam heating and other main components.

Using nitrogen as the heat conduction and transfer medium, it can achieve the drying production of suspensions, thick and viscous liquid materials containing organic solvents in the fields of pharmaceuticals, biochemistry, chemical engineering and biology, as well as the recovery of organic solvents, which is practical for low consumption, energy conservation and emission reduction. The unit adopts a closed-cycle technology, using nitrogen as the heat transfer medium. While drying liquid materials containing organic solvents, it recovers and utilizes the solvent through condensation cooling technology. To enhance the drying intensity and production capacity of the unit, this unit uses air-flow spray drying technology, that is, during the drying process of liquid materials (with a solid content of 50%), The liquid material is conveyed by the peristaltic pump to the air flow spray gun set in the drying tower (the spray gun can be set with 3 to 7 nozzles according to the production capacity requirements) for atomization into droplets. The droplets come into convective contact with the heat transfer gas from top to bottom and undergo heat transfer and heat exchange, so as to achieve the purpose of drying the moisture in an instant. The finished products are collected at the bottom of the drying tower. The superheated gas is discharged from the bottom of the drying tower by the circulating fan and separated by the solid-gas separator. The fine powder materials carried in the superheated air, after being subjected to the cutting cyclone effect of the solid-gas separator, settle to the bottom of the separator for collection. The superheated gas passes through the nitrogen back-blowing dust collector twice to capture the dust and materials carried in the gas. The residual heat gas enters the condenser and is cooled by the condenser medium (with a condensation temperature of 3℃). Condense to the dew point to achieve the recovery of organic solvents. The circulation system, after being supplemented with nitrogen, realizes the continuous drying production of a new round of nitrogen closed-loop circulation, so as to meet the process requirements of industrial production in the above-mentioned related industries.

Given the explosive and flammable safety hazards of organic solvents, this unit system simultaneously adopts safety technical means such as online oxygen measurement, overpressure relief, explosion-proof and explosion venting. Through intelligent control technology, it realizes the monitoring of oxygen residue in the system, pressure balance monitoring and automatic regulation control. When the air (oxygen) leakage rate within the system exceeds 0.9% (v/v), the oxygen measurement device will command the nitrogen replenishment valve through the control system to open and supply fresh nitrogen to the system, restoring the residual oxygen level within the system to the safe set value range (the closed-loop circulation system is designed for positive pressure, and the oxygen enters the circulation system through the feeding process). When the air pressure value within the system exceeds the set value (the air pressure balance value of the circulation system is set at 0.02mPa), the pressure relief device will automatically open the pressure relief pneumatic valve through instructions from the intelligent control center to release the overpressure gas. The explosion-proof and explosion relief device is another safety technical measure adopted by this unit, that is, when an electrical or key part of the system malfunctions, When the system malfunctions during normal operation and the air pressure rises to the safety limit value (the system's designed pressure resistance value is less than or equal to 0.05Mpa), the explosion-proof and venting device (composed of explosion-proof film, venting guide valve and venting components) will automatically open the directional venting and automatically cut off the power supply, closing the inlet and outlet pipeline valves, minimizing casualties and property losses to the greatest extent. Ensure production safety.

The advantages of the closed-loop circulation spray dryer are reflected

(1) This unit uses nitrogen as the heat transfer medium and nitrogen as the carrier. In a closed state, it achieves a closed-loop circulation, effectively ensuring the safety of drying liquid materials containing organic solvents and providing antioxidant protection for easily oxidized wet materials during the drying process.

(2) This unit adopts air flow spray drying technology, which enables it to achieve nitrogen-powered atomization of high-solid content, viscous and thick liquid materials that traditional centrifugal spray drying cannot match. As a result, it increases production capacity and reduces energy consumption by more than 70%, achieving a remarkable energy-saving and high-yield production effect.

(3) This unit adopts online monitoring and self-diagnostic control functions to ensure the safe production of drying liquid materials containing organic solvents. The intelligent control system has a high degree of automation.

(4) This unit realizes the recovery and utilization of materials containing organic solvents during the drying production process. On the basis of solving the problems of difficult drying and heavy pollution from exhaust gas emissions in related industries, it achieves the recovery and utilization of solvents, obtaining practical effects of energy conservation and emission reduction.