Product Overview

The spray drying and granulating unit is a device that can complete drying and granulation at the same time. According to process requirements, the pressure and flow rate of the feed liquid pump and the size of the spray orifice can be adjusted to obtain spherical granules of the required size ratio.

The working process of the spray drying and granulating unit is as follows: the feed liquid is fed in under high pressure by a diaphragm pump and sprayed out as a mist of droplets, which then descend co-currently with the hot air. Most of the powder granules are collected at the discharge outlet at the bottom of the tower; the exhaust gas and its fine powder are separated by a cyclone separator, the exhaust gas is discharged by the exhaust fan, and the powder is collected by a powder collecting cylinder arranged at the lower end of the cyclone separator. A secondary dust removal device can also be fitted at the fan outlet, giving a recovery rate of above 96–98%.

For the spray drying and granulating unit, the tower body, piping and separator — the parts in contact with the material — are all made of SUS304. Between the inner tower body and the outer shell there is sufficient insulation, filled with ultra-fine glass wool. The tower body is provided with an observation door, a sight glass, a light source and control instruments, all controlled and displayed from an electrical control console.

Spray Fluid Bed Dryer — Process Flow

(1) Gentle drying

Fluid bed drying is a particularly effective method of solids drying. During fluidization, liquid is drawn off from the entire surface of each particle. Its advantages include an excellent heat exchange effect and ideal drying times. In addition, the product is dried gently.

(2) Granulation – agglomeration

Agglomeration in a fluid bed is a modern method of producing granules from powder using liquid bridges. The sprayed liquid can be water or an organic solvent, a powder dissolved in a liquid, or another binder. The moistened granules are then dried and, where necessary, cooled. Because the mechanical forces in a fluid bed are relatively small, the agglomerates/granules are relatively loose, with a low bulk density, and are very readily soluble in water.

(3) Powder coating – particle coating

Modern film coating technology selectively influences product properties by applying a protective film. During coating, uniform application of the coating material is crucial. The coating must be absolutely sealed, with no mechanical damage or tears. Film coating is a highly demanding process with an extremely wide range of applications.

(4) Direct granulation

In the granulation process, powder is mixed and moistened. At the same time, a solvent or binder can be added. Centrifugal motion produces agglomerates, which are rounded into uniform, dense granules. Selective product properties can be achieved through direct granulation or layering.

Spray Fluid Bed Dryer — Performance Features

(1) Fast drying speed: after atomization the surface area of the feed liquid is greatly increased, and in the hot air stream 95%–98% of the moisture can evaporate instantly, with drying completed in only ten-odd to several tens of seconds. It is particularly suitable for drying heat-sensitive materials.

(2) All products are spherical granules with uniform particle size, good flowability and good solubility, high product purity and good quality.

(3) Wide application range: depending on the characteristics of the material, hot air can be used for drying or cold air for granulation, giving strong adaptability to materials.

(4) Simple and stable operation, convenient control, and easy to automate.

Spray Fluid Bed Dryer — Product Applications

(1) Pharmaceutical industry: granules for tablets, instant granules and capsules; low-sugar and sugar-free granules of Chinese patent medicines;

(2) Food: cocoa, coffee, milk powder, granulated fruit juice, seasonings, etc.;

(3) Other industries: pesticides, feed, fertilizers, pigments, dyes, etc.

Item	Unit	PGL-3B	PGL-5B	PGL-10B	PGL-20B	PGL-30B	PGL-80B	PGL-120B
Liquid extract — min	kg/h	2	4	5	10	20	60	100
Liquid extract — max	kg/h	4	6	15	30	40	100	140
Fluid-bed capacity — min	kg/batch	2	6	10	30	60	100	150
Fluid-bed capacity — max	kg/batch	6	15	30	80	160	250	450
Liquid specific gravity	kg/L	≤1.30	≤1.30	≤1.30	≤1.30	≤1.30	≤1.30	≤1.30
Feed container volume	L	26	50	220	420	620	980	1600
Container diameter	mm	400	550	770	1000	1200	1400	1600
Induced draft fan power	kW	3.0	5.5	7.5	11	15	18.5	30
Auxiliary fan power	kW	0.35	0.75	0.75	1.20	2.20	2.20	4
Steam — consumption	kg/h	40	70	99	210	300	366	465
Steam — pressure	MPa	0.40–0.60	0.40–0.60	0.40–0.60	0.40–0.60	0.40–0.60	0.40–0.60	0.40–0.60
Electric heating power	kW	9	15	21	25.5	51.5	60	75
Compressed air — consumption	m³/min	0.5	0.8	0.8	0.9	1.1	1.3	1.8
Compressed air — pressure	MPa	0.40–0.60	0.40–0.60	0.40–0.60	0.40–0.60	0.40–0.60	0.40–0.60	0.40–0.60
Operating temperature	°C	Room temperature–160 °C, automatically controlled	←	←	←	←	←	←
Product moisture	%	≥0.2	≥0.2	≥0.2	≥0.2	≥0.2	≥0.2	≥0.2
Material yield	%	≥99	≥99	≥99	≥99	≥99	≥99	≥99
Equipment noise	dB	<77	<77	<77	<77	<77	<77	<77
Main unit dimensions — Φ	mm	400	550	770	1000	1200	1400	1600
Main unit dimensions — H1	mm	940	1050	1070	1220	1570	1590	1690
Main unit dimensions — H2	mm	1900	2360	2680	3150	3630	4120	5050
Main unit dimensions — H3	mm	2050	2590	3020	3600	4180	4770	5800
Main unit dimensions — B	mm	740	890	1110	1420	1620	1820	2100

Example: a batch is required to process 120 kg of liquid extract (30 % solids) together with 60 kg of seed material. From I and II the theoretical product mass is obtained as M = m_I × 30 % + m_II = 120 kg × 30 % + 60 kg = 96 kg, and the working time is T = 120 kg ÷ 30 kg/h = 4 h. The fluid-bed capacity in the technical data table gives the standard load range; two batches can therefore be completed per shift, so model PGL-30 is the appropriate choice.