The latest progress in alcohol residue drying technology and equipment
Alcohol residue is the residue used in the production of alcohol, which is 0.65 times the amount of alcohol produced. Alcohol lees contain varying degrees of protein and other useful elements, and their protein content is high (corn lees). Dried products can reach 28% to 30%, and can be used as high-quality feed, with a market price of over 1000 yuan/ton; Cassava lees with low protein content can also be used as feed or fertilizer, and the market price of dry products is also between 300-350 yuan/ton.
At present, various types of alcohol in China have an annual output of nearly 30 million tons of synthetic alcohol. If the output of distiller's grains is 0.65 times that of alcohol, the quantity is considerable. If it is dried in a timely manner, it will be a considerable asset.
But if left untreated or mishandled, alcohol lees will ferment and deteriorate in a short period of time, causing serious environmental pollution.
In recent years, scholars and experts at home and abroad have attached great importance to this, and there has been significant development in the drying technology and equipment of alcohol lees:
Currently, there are two main categories of alcohol residue drying equipment internationally
One is a tube bundle dryer using steam as the heat source; One is a drum dryer using hot air as the heat source.
Tube bundle dryer using steam as heat source
Schematic diagram of tube bundle dryer
1. Structural Principles
Two high-pressure heads are connected by several steel pipes, with hollow shafts on both sides of the air head supported by bearings. One end of the electric motor drives the tube bundle to rotate at low speed through a reducer. The steam pipeline is connected to the hollow shaft through a rotating joint, and the steam enters the tube bundle through the rotating joint. The wet material entering from the feeding port contacts the tube bundle for heat exchange, causing the moisture of the wet material to evaporate. Due to the rotation of the tube bundle, The outer spiral plate drives the material to move from the inlet to the outlet, gradually evaporating the moisture of the material until it meets the drying requirements. The finished product is discharged from the discharge port, and the latent heat of steam in the tube bundle is released and condensed into hot water. It is discharged from the hollow shaft on the other side through a rotating joint.
Main performance indicators:
1. The drying strength of the tube bundle is 4.5-5 kg/m2 (steam pressure is 6 kg/cm2)
2. Steam consumption: 1.4 kg/1 kg of water
3. Reference price: 1000 yuan/m2 (tube bundle area)
Features:
1. Compact equipment with small footprint
2. Stable work and easy operation
3. Available evaporator waste heat
Disadvantages:
1. The pipe wall is prone to corrosion, has a short lifespan, is inconvenient to maintain, and has high maintenance costs
2. Utilizing secondary energy (steam), resulting in lower overall thermal efficiency
3. High drying cost
Suitable for enterprises with surplus steam.
Multi ring drum dryer
Structural features:
1. Three sets of drums with different diameters form a multi ring drum. The inner and outer surfaces of the inner and middle ring drums, as well as the inner surface of the outer ring drum, are equipped with reading plates. The three-layer drum rotates at the same speed, and the material direction is: wet material enters the inner drum, returns from the end, enters the middle drum, goes to the first end, then enters the outer drum, and finally discharges from the end of the outer drum.
Advantages over traditional single-layer rollers:
1. The length has been reduced by two-thirds, resulting in a corresponding reduction in the factory area
2. The steel consumption of the machine is greatly reduced, and due to its reduced weight, the installed capacity is greatly reduced, resulting in a corresponding reduction in electricity consumption.
3. The cross-sectional area of the three ring drum can be determined based on the object
Disadvantages:
1. The pipe wall is prone to corrosion, has a short lifespan, is inconvenient to maintain, and has high maintenance costs
2. Utilizing secondary energy (steam), resulting in lower overall thermal efficiency
3. High drying cost
Suitable for enterprises with surplus steam.
Multi ring drum dryer
Structural features:
1. Three sets of drums with different diameters form a multi ring drum. The inner and outer surfaces of the inner and middle ring drums, as well as the inner surface of the outer ring drum, are equipped with reading plates. The three-layer drum rotates at the same speed, and the material direction is: wet material enters the inner drum, returns from the end, enters the middle drum, goes to the first end, then enters the outer drum, and finally discharges from the end of the outer drum.
Advantages over traditional single-layer rollers:
1. The length has been reduced by two-thirds, resulting in a corresponding reduction in the factory area
2. The steel consumption of the machine is greatly reduced, and due to its reduced weight, the installed capacity is greatly reduced, resulting in a corresponding reduction in electricity consumption.
3. The cross-sectional area of the three ring drum can be designed based on the drying characteristics of the material, which means that the material has different precipitation stages and travel times inside the drum, greatly improving the machine performance.
4. Good insulation effect and high heat utilization rate.
