By-product of Ethanol Production - DDGS
Ethanol manufacturers use ethanol to produce two main basic products - ethanol fuel and distillers' lees. Most ethanol manufacturers have introduced a diverse portfolio of products, including biofuels, plastics, fertilizers, carbon dioxide, disinfectants, and animal feed as a way to boost revenue.
There are two kinds of corn distillers protein feed products in the market: one is DDG (Distillers Dried Grains), which is a feed obtained by simply filtering the corn distillers, draining the clear liquid, and drying the filter residue. The other is DDGS (Distillers Dried Grains with Solubles), a feed obtained by drying and concentrating the clear liquor and then mixing it with the filter residue, in which starch is converted into ethanol and carbon dioxide, while other nutrients such as protein and fiber are retained. The total amount of energy and nutrients in the latter is significantly higher than the former. As a new protein feed material, DDGS has a high protein content and can be fed directly to ruminants, making it a high-quality per-rumen protein for ruminants.
In the U.S., the cattle industry uses about 80% of the total DDGS, with beef cattle accounting for about 50% and dairy cattle for about 30%. The development of corn seed separation and fractionation technology in the ethanol production process has helped to develop functional protein products and meet the nutritional needs of different livestock species.
How to produce DDGS
In the DDGS production process, stillage separation is a key process, and the separation effect is directly related to the manufacturers' cost control of DDGS. In DDGS production, separation equipment has gradually developed from plate and frame filter presses, rotary drum vacuum filters, and three-foot filter centrifuges, to the most used decanter centrifuges now. As more and more large alcohol plants are established, higher requirements are placed on the ability of separation equipment to adapt to plant production. Based on the outstanding advantages of decanter centrifuges in terms of mechanical performance, floor space, equipment costs, maintenance costs, labor costs, impact on the environment, production capacity, etc., more and more alcohol manufacturers are using decanters as the preferred equipment for the separation and treatment of stillage.
Structure and working principle of decanter centrifuge
The main body of the decanter centrifuge consists of three parts: the bowl part, the screw part and the drive unit. Between them, the bowl and screw differential speed is adjusted by a gearbox.
- The stillage liquid enters the intersection of the cone and cylinder of the bowl from the feed tube that passes through the hollow part of the screw conveyor.
- After the stillage liquid enters the drum, the liquid in it is distributed in the drum to form an inner water ring.
- The solid phase material settles on the inner wall of the bowl under the action of centrifugal force, and the screw conveyor continuously carries the solid from the cylindrical part of the drum through the conical part to the discharge port.
- The separation of solid and liquid phases occurs in the cylindrical part of the bowl with a weir plate (adjustable and replaceable) at the large end of the bowl, through which the clarified liquid phase overflows and is collected at the large end of the bowl.
Advantages of Using ZK DDGS Centrifuges
Special Spiral Structure - Productivity Improvement
The DDGS high-efficiency centrifuge fully draws on the working principle of the lamella settler. To improve the clarity of the supernatant after centrifuge separation, a certain number of solid particles capturing plates (referred to as spiral plates) are added to the screw conveyor at the clarification section. When the solid suspended particles flow through the spiral ramp, part of them can be effectively attached to the spiral ramp and slide along it into the blades of the screw conveyor to realize continuous slag discharging. Compared with common centrifuges, it can increase 20~30% in solid recovery rate.
Variable Pitch Technology - Handling Capacity Improvement
The high-efficiency centrifuge for glutamic acid fully considers the number of solids in the high-concentration glutamic acid slurry, and fully adopts the variable pitch technology in the structural design process, exerting the slag conveying performance of the spiral blade to the maximum extent without causing the lifting angle of the spiral blade to disturb the solid particles and effectively improving the processing capacity of the centrifuge.