GXZ series high-efficiency rotating thin film evaporator-Changzhou Binda Drying Granulation Equipment Co., Ltd

Product overview

The GXZ series high-efficiency rotating thin film evaporator, also known as the scraper evaporator, is a new type of high-efficiency evaporator that uses a rotating scraper to force film formation and can perform falling film evaporation under vacuum conditions. It has a high heat transfer coefficient, high evaporation intensity, short overcurrent time, and high operational flexibility, making it particularly suitable for the evaporation concentration, degassing and desolvation, distillation and purification of thermosensitive materials, high viscosity materials, and easily crystallized granular materials. Therefore, it has been widely used in industries such as chemical, petrochemical, pharmaceutical, pesticide, daily chemical, food, and fine chemical.

Working principle

The material enters the evaporator radially from above the heating zone, and is distributed to the heating wall of the evaporator through the distributor. Then, the rotating scraper continuously and uniformly scrapes the material into a thin and uniform liquid film on the heating surface, and pushes it downwards in a spiral shape. During this process, the rotating scraper ensures continuous and uniform liquid film to generate high-speed turbulence, and prevents the liquid film from coking and scaling on the heating surface, thereby improving the total transfer coefficient. Light components are evaporated to form a steam stream that rises and passes through a vapor-liquid separator to reach an external condenser directly connected to the evaporator. Heavy components are discharged from the cone at the bottom of the evaporator.

A unique distributor not only can evenly flow the materials to the inner wall of the evaporator to prevent the materials from splashing into the evaporator and injecting steam, but also can prevent the newly entered materials from flashing here, which is conducive to the elimination of foam. Materials can only evaporate along the heating surface. A centrifugal separator designed based on material characteristics is installed at the upper part of the scraper evaporator to separate the liquid droplets in the rising steam flow and return them to the distributor.

Scraper type

Due to the movement of the scraper, the material is continuously scraped into a thin film on the evaporation surface, creating a turbulent state to achieve the effect of thin film evaporation. According to the viscosity and other characteristics of the material, evaporators can be divided into the following types of scraper forms:

Activity scraper: Activity scraper is a basic and common form of scraper. The forms of the activity scraper include SR type, SL type, DR type, and DL type, with a guide groove inclination angle of 30 °, 45 °, or 60 °.

Fixed scraper: the fixed scraper is made of metal material, which is rigidly connected to the rotor. The length of the scraper is the same as that of the evaporation cylinder. The gap between the rotating scraper and the inner wall of the i evaporation cylinder is only 1+2mm, requiring high processing and installation accuracy. It is suitable for the evaporation, concentration, dissolution or purification of materials with extremely high viscosity and easy to form foam.

Spiral scraper: This scraper is suitable for concentrating materials with poor fluidity, easy scaling, and extremely high viscosity. When the rotor rotates, the concentrated material flows smoothly downwards due to the thrust of the spiral scraper.

Hinge scraper: hinge scraper is suitable for materials that are prone to scaling or have moderate viscosity on heating surfaces.

Equipment features

The rotating thin film evaporator has the following unique advantages that cannot be compared to conventional film evaporators:

1. Minimal pressure loss

In an efficient rotating thin film evaporator, the material flow and the secondary evaporation steam flow are two independent channels: the material descends along the inner wall of the evaporator cylinder (forced film formation), while the secondary steam evaporated from the evaporation surface leaves the evaporator almost unobstructed from the central space of the cylinder, resulting in minimal pressure loss (or resistance drop).

2. Can operate under true vacuum conditions

Due to the extremely low resistance of the secondary vapor from the evaporation surface to the condenser, the evaporation surface on the inner wall of the entire evaporation cylinder maintains a high vacuum degree (up to -750mmHg), almost equal to the vacuum degree at the outlet of the vacuum system. As the vacuum degree increases, the boiling point of the processed material is effectively reduced.

3. High heat transfer coefficient, high evaporation intensity

The decrease in boiling point increases the temperature difference with the heat medium; The turbulent liquid film reduces thermal resistance; Simultaneously suppressing material coking and scaling on the wall, and also improving the heat transfer coefficient of the evaporator wall; Therefore, the heat transfer coefficient of the high-efficiency rotating thin film evaporator can reach up to 8000KJ/h.m2. ℃, resulting in a high evaporation intensity.

4. Low temperature evaporation

Due to the high vacuum level maintained inside the evaporator, the boiling point of the processed material is greatly reduced, making it particularly suitable for low-temperature evaporation of thermosensitive materials.

5. Short overcurrent time

The overcurrent time of the material in the evaporator is very short, about 10 seconds; For commonly used activity scrapers, there are guiding grooves on the end face of the material being scraped, and the angle of inclination is usually 45 ℃. Changing the angle of inclination can change the flow time of the material. Under the scraping of the scraper, the material spirals down and leaves the evaporation section. Shorten the overcurrent time and effectively prevent the decomposition, polymerization, or deterioration of the product during the evaporation process.

6. Low grade steam can be utilized

Steam is a commonly used heat medium. By reducing the boiling point of the material, the temperature of the heating medium can be lowered while ensuring the same Δ t. Utilizing low-grade steam is beneficial for the comprehensive utilization of energy.

7. Strong adaptability and easy operation

The unique structural design allows this product to handle materials with high viscosity, particle content, thermal sensitivity, and easy crystallization that are difficult to handle with conventional evaporators.

The rotary thin film evaporator has high operational flexibility, stable operating conditions, low maintenance workload, and easy maintenance.

Note:

1. The above external dimensions may vary slightly from the actual equipment, for reference only. Please refer to the drawings provided by our company after placing the order;

2. The weight D represents the outer diameter of the jacket, and Dn represents the inner diameter of the evaporator cylinder;

3. Jacket pressure: Typically designed for 0.4MPa steam, it can also be designed separately according to user requirements. When using thermal oil, it can also be designed separately;

4. Vacuum degree of evaporation inner cylinder: It is usually -0.09MPa (about -680mmHg), but can also be adjusted to -0.095MPa (about -720mmHg) and -0.0986Mpa (about -750mmHg) according to user needs;

5. Main cylinder body (part in contact with the material) and jacket material: Carbon steel, SUS304, 316L, 316Ti or titanium materials can be used according to user and actual needs;

6. Total weight of equipment: does not include material weight.

Application scope

Scraper type thin film evaporators have been widely used in heat exchange engineering. Especially for heat sensitive materials and short residence time heat exchange, the scraper is beneficial for heat exchange, and through different scraper designs, complex product distillation can be carried out. Scrap film evaporators have been used in the following fields for the purpose of evaporation concentration, desolvation, stripping, reaction, degassing, deodorization, etc., and have achieved good results.

Chinese and Western medicine: antibiotics, sugar solution, Chinese herbal medicines such as Leigongteng and Huangqi, intermediates such as methyl imidazole and mononitrile amine;

Light industrial food: juice, gravy, pigment, essence, spice, enzyme preparation, lactic acid, xylose, starch sugar, potassium sorbate;

Oil and daily chemical products: Phosphatidyl esters, VE， Fish liver oil, oleic acid, glycerol, fatty acids, waste lubricating oil, alkyl polyglycosides, alcohol ether sulfates, etc;

Synthetic resins: polyamide resin, epoxy resin, polyformaldehyde, PPS (polypropylene sebacate), PBT， Acrylic formate;

Synthetic fibers: PTA, DMT, carbon fiber, polytetrafluoroethylene, polyether polyols, etc;

Petrochemical: TDI, MDI, trimethylhydroquinone, trimethylolpropane, sodium hydroxide, etc;

Pesticide organisms: herbicides such as acetochlor, propiconazole, chlorpyrifos, furan phenol, and chlorfenapyr, insecticides, herbicides, and acaricides;

Wastewater: inorganic salt wastewater, etc;