Multilayer paddle dryer

The multi-layer paddle dryer manufactured by RD Drying Equipment Co., Ltd. has strong adaptability to various materials, and the coverage of the promotion and application is very wide. It has now entered the stage of promotion and application. The issue of environmental protection in the process of economic development has received the attention of the international community. Our disposal of waste materials is aimed at stabilizing, reducing, harmless and resource-reducing.

According to the disposal purpose of waste materials, most of the treatment methods need to be dried, such as disposal of various sludges, disposal of various chemical gypsum, disposal of various industrial wastes, disposal of calcium carbide mud, and other industrial wastes. Disposal, the problem of dry solid waste is raised, how to solve it? Luoyang Ruidao Drying Engineering Co., Ltd. has used the dry island network for many years to conduct extensive and in-depth investigation and research with our alliance experts, experts in alliance enterprises and universities, research institutes, and experts in waste discharge units. And with information integration, technology integration, and technology migration processing, our unanimous conclusions are:

1. The problem of drying solid waste treatment can be solved, but the following requirements must be met: large processing capacity, low operating energy consumption, and no secondary pollution;

2. At present, although there are certain levels of drying technology in China, there is no drying process and equipment that are compatible with the characteristics of waste solids treatment;

3. International waste solids treatment technology and equipment are not suitable for China’s national conditions.

The solution to this problem is to carry out technical integration and technology transfer on the basis of China’s drying technology and equipment, to develop a drying process and equipment suitable for China’s national conditions and to adapt to the characteristics of solid waste treatment. Luoyang Ruidao Dry Engineering Company organizes experts to present China’s drying technology and equipment for analysis and demonstration, technology integration, the use of more than one million years of investment, the development of RD multi-layer hollow dryer, has been widely used in municipal, chemical, pharmaceutical, printing and dyeing industries, now for all types of The drying treatment of the sludge is as follows:

First, the status quo of sludge treatment and disposal

The treatment and disposal of sludge is a huge and complicated comprehensive process. It is an important and urgent task, and the effective treatment and disposal of sludge has been mentioned on an important agenda.

The characteristics of the sludge are combined: first, the water content is high, generally above 75%, and the drying shrinkage ratio is large; second, the amount is large, the stacking area is large, and the transportation cost is high; and the third is rich in organic matter and rich in nitrogen and phosphorus. Potassium nutrients; Fourth, contaminants containing heavy metal pathogenic microorganisms and malodorous gases.

The principles of sludge treatment and disposal are: first, stabilization, second, reduction, third, harmlessness, and fourth, resource utilization.

The methods currently used in sludge treatment and disposal are: landfill, composting, incineration, building materials, etc. In view of the unique and complex characteristics of sludge, various methods are comprehensively disposed of in accordance with the basic principles of treatment and disposal. It can be said that the drying of sludge is an important link, and the drying equipment needs mature technical support. At the same time, the drying equipment should have the functions of large processing capacity, low operating cost, no pollution, and more selective disposal.

Second, multilayer paddle dryer introduction

RD multi-layer hollow dryer is a new type of drying device developed on the basis of the original hollow blade dryer. The whole set of equipment transplants the mature technology of the dry material of the hollow blade dryer, and is also equipped with heat pump heat recovery technology and multi-effect evaporation energy-saving technology. The three technologies are combined through a multi-layer structure. A large-scale manufacturing of a hollow blade dryer has been realized. It is a drying device that can process materials in large quantities. Conveniently combined with heat pump heat recovery technology, the use of dry and evaporated secondary steam as a heat source to achieve multi-effect drying, greatly reducing the heat consumption of the drying process, drying the volatilized steam into condensed water discharge, solving the malodorous gas generated in the sludge drying process The problem.

Multilayer paddle dryer structure features:

The entire device is a superposition of several work units in the vertical direction. Each work unit is independently operated under the specific process environment position, and the entire device is combined with the continuous completion of the process task. It is structurally multi-layered and functionally multi-level.

Each unit layer can be considered a modified version of a hollow blade dryer. It is composed of two vane shafts, a W-shaped housing, a base and a transmission part that are in mesh with each other.

It is equipped with heat pump heat recovery facilities, multi-effect evaporation (what is multi-effect evaporation) energy-saving facilities, material addition facilities, dust recovery facilities, and finished product delivery facilities.

According to the requirements of material characteristics, finished product standards, production requirements and site layout conditions, the unit can be increased or decreased in a single layer heat exchange area, and the appropriate number of layers can be arranged; the rotation speed of the blade shaft can be adjusted between 5-20 rpm; Layer feeding and selection of multilayer feeds, etc. The blades of different shapes are designed and selected according to the changes of the physical properties of the particles in the drying process, the change of the evaporation rate of water, the change of the comprehensive heat transfer coefficient, the structural design of the blades at all levels, and the operating parameters.

Multilayer paddle dryer works:

The material is added at the uppermost feeding port, and after drying through the stage, it enters the next layer to perform the second-stage drying, and successively realizes multi-stage drying. The basic principle of single layer operation is the same as that of hollow blade dryers. Due to the high water content before drying, the supplementary feeding port is supplemented in the secondary drying. During the drying process, the secondary dried material is granular, the volatile area is large, and the heat transfer surface is updated quickly. The heat coefficient is large, which is conducive to rapid drying, and the supplemental feeding mode is beneficial to increase the drying rate.

The multi-layer blade dryer uses steam or heat-conducting oil as the heating medium, and heat medium is introduced into the inner cavity of the dryer blade shaft and the jacket layer of the casing to be heated at the same time, and the material is heated and dried by conduction heating.

The special feeding mechanism of the dried wet material is continuously and evenly added into the drying device casing, and the material is turned, stirred and mixed by the rotation of the hot shaft of the blade, and the heating interface is continuously updated to fully contact the heated casing and the blade. To evaporate the moisture on the surface of the material. At the same time, the material is conveyed in the direction of the discharge port with the rotation of the blade shaft, and the stirring is continued during the transportation, so that the water oozing out from the material continues to evaporate. The uniformly dried product is discharged from the discharge port.

According to the energy-saving principle of the multi-effect evaporator, the device adopts multi-effect drying, and the multi-stage dried volatilized steam is compressed by the compressor to remove the condensed water, and the saturated steam formed enters the lower stage as the dry heat source of the next stage. Make the heat fully utilized. The device finally completely converts the volatilized water vapor into condensed water, no exhaust gas is discharged, and no exhaust gas treatment device is needed to avoid secondary exhaust gas pollution.

The volatile gas inside the device is discharged from the uppermost volatile medium outlet step by step from the bottommost chamber. Since the bottom layer is a relatively dry material, the uppermost layer is a paste-like material. From top to bottom, the gas velocity is gradually reduced, due to the stepwise change of the vapour gas flow rate and the change of the moisture content of the material, and the gas is dry. The baffle effect in the device, the dust in the gas discharge drying device is entrained with little or no dust entrainment.

Device features:

1. The device has a compact structure and a small footprint. It can be seen from the structure of the device that the heat required for drying is mainly provided by the hollow blade wall surface arranged on the hollow shaft, and the heat transfer amount of the jacket wall surface is only a small part. Therefore, the heat transfer surface of the unit volume equipment is large, which can save equipment footprint and reduce capital investment.

2. Especially after the multi-layer structure is adopted, the floor space is only 1/5-1/6 of the hollow blade dryer of the same heating area. High heat utilization and low operating costs. The heat required for drying is not hot air heat exchange, which reduces the heat loss carried by the hot gas. Due to the compact structure of the device and the small number of auxiliary devices, the heat loss is also reduced. The heat utilization rate can reach 80%-90%. The multi-effect drying is adopted, and the dry and evaporated secondary steam is used as a heat source, and only 250-300 kg of steam per ton of sludge is required.

3. The wedge-shaped blade has self-cleaning ability, which can improve the heat transfer effect of the blade. The dispersive force generated by the combined movement of the inclined surface of the rotating blade and the particle or powder layer automatically removes the material attached to the heating ramp, and the blade maintains an efficient heat transfer function. In addition, due to the reverse rotation of the two-axis blades, the material is alternately segmented (when the two-axis blade is closest to each other) and the material is expanded (the farthest distance between the two-axis blades), so that heat transfer The material near the surface is stirred agly, improving the heat transfer effect. The wedge-shaped paddle mixer has a high heat transfer coefficient of 85-350 W/(M2•K).

4, the amount of gas is small, can reduce or save some auxiliary equipment. Since no gas is required for heating, the amount of gas used in the drying process is greatly reduced.

5. Due to the small amount of gas, the gas flow rate in the dryer is low, and the dust emitted by the gas is less. The gas dust recovery of the system after drying is convenient, the size of the cyclone separator can be reduced, and the bag filter can be omitted or reduced. Gas heaters, blowers, etc. can be scaled down, saving equipment investment.

6. The material has wide adaptability and the product is evenly dried. The dryer is provided with an overflow weir, which can adjust the residence time of the materials in the dryer according to the nature of the material and the drying conditions, so as to adapt to the drying requirements of the difficult-to-dry materials and the high-moisture materials. In addition, the feed rate, the shaft speed and the heat carrier temperature can be adjusted, and the material residence time can be arbitrarily selected between several minutes and several hours. Therefore, the material is very adaptable (dryable aqueous powder material, paste material, block cake material, liquid material, etc.). In addition, a plurality of stirring blades are arranged in the dryer to make the material fully mixed in the dryer from the feeding port to the discharging port, and the product is dry and stable.

7, suitable for a variety of drying operations. It has been previously described that wedge-shaped paddle drying can be used to adjust the drying process conditions by various methods, and its operation is easier to control than fluidized bed drying and airflow drying operations, and is suitable for various operations.

8. It adopts multi-layer structure, multi-layer assembly, large-scale manufacturing, transportation and convenient installation. The heat transfer area of ​​a single unit can reach 800m2.

9, a single set of processing capacity.

10, no secondary pollution, no need for exhaust gas treatment equipment.

11, the entire device is fully automated control.

Third, multi-layer hollow blade dryer model spectrum

L-type structure spectrum

L-shaped structure	Single layer	2 layer	3 layer	4 layer	5 layer	6 layer
	RD20	RD20×2	RD20×3	RD20×4	————	————
	RD25	RD25×2	RD25×3	RD25×4	————	————
	RD30	RD30×2	RD30×3	RD30×4	————	————
	RD35	RD35×2	RD35×3	RD35×4	————	————
	RD40	RD40×2	RD40×3	RD40×4	————	————
	RD40	RD40×2	RD40×3	RD40×4	————	————
	RD45	RD45×2	RD45×3	RD45×4	————	————
	RD50	RD50×2	RD50×3	RD50×4	————	————
	RD50	RD50×2	RD50×3	RD50×4	————	————
	RD80	RD80×2	RD80×3	RD80×4	————	————
	RD100	RD100×2	RD100×3	RD100×4	————	————
	RD120	RD120×2	RD120×3	RD120×4	————	————
	RD150	RD150×2	RD150×3	RD150×4	RD150×5	————
	RD180	RD180×2	RD180×3	RD180×4	RD180×5	————
	RD200	RD200×2	RD200×3	RD200×4	RD200×5	————
	RD250	RD250×2	RD250×3	RD250×4	RD250×5	————
	RD280	RD280×2	RD280×3	RD280×4	RD280×5	————
	RD300	RD300×2	RD300×3	RD300×4	RD300×5	RD300×6
	RD350	RD350×2	RD350×3	RD350×4	RD350×5	RD350×6

Π-structural spectrum

Π-structural spectrum	Single layer	2 layer	3 layer	4 layer	5 layer	6 layer
	RD20	RD20×2×2	RD20×2×3	RD20×2×4	————	————
	RD25	RD25×2×2	RD25×2×3	RD25×2×4	————	————
	RD30	RD30×2×2	RD30×2×3	RD30×2×4	————	————
	RD35	RD35×2×2	RD35×2×3	RD35×2×4	————	————
	RD40	RD40×2×2	RD40×2×3	RD40×2×4	————	————
	RD40	RD40×2×2	RD40×2×3	RD40×4	————	————
	RD45	RD45×2×2	RD45×2×3	RD45×2×4	————	————
	RD50	RD50×2×2	RD50×2×3	RD50×2×4	————	————
	RD50	RD50×2×2	RD50×2×3	RD50×2×4	————	————
	RD80	RD80×2×2	RD80×2×3	RD80×2×4	————	————
	RD100	RD100×2×2	RD100×2×3	RD100×2×4	————	————
	RD120	RD120×2×2	RD120×2×3	RD120×2×4	————	————
	RD150	RD150×2×2	RD150×2×3	RD150×2×4	RD150×2×5	————
	RD180	RD180×2×2	RD180×2×3	RD180×2×4	RD180×2×5	————
	RD200	RD200×2×2	RD200×2×3	RD200×2×4	RD200×2×5	————
	RD250	RD250×2×2	RD250×2×3	RD250×2×4	RD250×2×5	————
	RD280	RD280×2×2	RD280×2×3	RD280×2×4	RD280×2×5	————
	RD300	RD300×2×2	RD300×2×3	RD300×2×4	RD300×2×5	RD300×2×6
	RD350	RD350×2×2	RD350×2×3	RD350×2×4	RD350×2×5	RD350×2×6

Vacuum structure spectrum

1	2	3	4	5
RDZ20	RDZ30	RDZ40	RDZ60	RDZ100
RDZ25	RDZ35	RDZ50	RDZ80	RDZ120
———	RDZ40	———	———	RDZ150