Storage Silos

The feed mill steel silo project generally consists of a silo and a working tower, equipped with necessary process equipment and conveying machinery.

• When it comes to silos, the first thing to consider is silo size.
• To determine the size and capacity of the silo, multiple factors such as land occupation, procurement, cargo flow, loading and unloading, feed production scale, and production and processing technology need to be comprehensively considered.
• For the work tower, it is necessary to consider the mechanical equipment and related floor layout required to realize the various process system functions of the steel plate silo.

For the process design of steel plate animal feed storage silos in feed mills, a design brief must first be prepared based on production needs and land area.

It roughly includes:

• Project composition and layout
• Select the warehouse type and determine the warehouse capacity
• Choose process equipment
• Design workflow
• Carry out technical and economic comparison of process plans.
• Select the best process design plan with high production efficiency, small investment and low management costs

The general plan layout of steel plate storage silos should be as feasible as possible to adapt to production, save land, be economical in cost, facilitate construction, and have smooth cargo flow. The following layout principles should be considered:

• It must be combined with the overall development plan of the animal feed mill and reasonably arranged according to geological and hydrological conditions.
• Reasonably arrange according to the grain loading and unloading process to ensure the continuity of grain receiving and distribution operations, and make all transportation routes reasonable and smooth.
• Correctly combine buildings, shorten the distance between each other as much as possible, and shorten the process operation route as much as possible to reduce investment and management costs.
• Construction requirements must be met, and sufficient passages should be left between buildings.
• Must meet fire prevention and hygiene requirements. There will be a lot of dust during the transportation of grain, which seriously affects environmental protection and workers’ operations, and may cause dust explosions. Therefore, fire prevention, safety, and sanitary conditions must be carefully considered.

Build a new feed factory, reasonably determine the storage capacity of the vertical silo, the area of the room-type raw material warehouse and the finished product warehouse, and control the reasonable inventory.

It is of great significance to ensure the continuity and stability of production, reduce feed costs, and improve the economic benefits of enterprises. It can also prevent the increase in investment costs caused by excessive storage capacity construction.

However, there is no consensus on how to determine reasonable warehouse capacity.

• Warehouse capacity is too small, which affects production efficiency and continuity of production, may result in frequent procurement of raw materials, and increases procurement and inspection costs.
• If the warehouse capacity is too large, in addition to the increase in investment costs, it will inevitably increase storage costs such as interest on funds occupied by raw materials and finished products and losses during the storage period.

The inventory of each raw material is related to the design daily output of the feed factory, the proportion of the raw material in the formula, and the storage days of the raw material.

For a feed factory, after its product plan, product formula, and production scale are determined, the daily demand for each raw material can be estimated, and then the amount of material that should be allocated is calculated based on the storage days of each raw material.

• It is generally believed that for main raw materials such as corn with sufficient raw material supply and convenient transportation, the storage period is 7 to 10 days.
• When the feed factory is far away from the main raw material supply area and requires a long transportation time, the storage period can be considered as 20 to 30 days;
• For raw materials with strong seasonal characteristics, the storage period can be as long as more than 3 months.

The working tower is the production center of the steel plate storage silos. The working tower is equipped with the necessary mechanical equipment to complete various process systems of the steel plate silo.

Its task is to transport, lift, clean, measure, and remove dust from the received grain and then transport it to various silos for storage. It can transport and release the grain out of the warehouse as needed, or carry out silo dumping operations.

Some working towers are also equipped with drying equipment to process grains with higher moisture content.

• The building area and height of the work tower are determined based on the size and layout of the process equipment selected on each floor.
• The size of the entire work tower construction area should be calculated based on the floor with the largest equipment layout, and the layout locations of elevators, stairs, and hanging holes should be taken into consideration.
• While arranging machinery and equipment reasonably, factors such as equipment maintenance and ease of loading and unloading should also be taken into consideration.
• The height of each floor should be determined according to the height of the equipment on each floor, the convenience of installation and maintenance, and the angle of the grain gravity pipe.

Mechanical equipment mainly includes:

• Grain feeding machinery: truck unloader, ship unloader, belt conveyor, air cushion belt conveyor, buried scraper conveyor, bucket elevator, etc.
• Grain discharging machinery: bottom auger, clearance scraper, loading machine, ship loader, packaging machine, belt conveyor, scraper, etc.;
• Weighing machinery: ground scale, truck scale, rail scale, mechanical scale, electronic scale, etc.;
• Cleaning machinery: white balance vibrating screen, plane rotary screen, squirrel cage screen, cone screen, classification screen, magnetic separator, etc.;
• Ventilation machinery: including ventilation and dust removal, mechanical ventilation, pneumatic conveying, cleaning equipment, etc.;
• Storage machinery: sampler, fumigation device, etc.

 The selection and layout of equipment should comply with the following principles:

• Configure equipment according to storage silos process requirements to make it a continuous automated production process.
• The production capacity of connected conveying equipment should be coordinated. When the production volume of a certain operating equipment in the process does not meet the production capacity of the system, corresponding measures should be taken to ensure the continuity of process operations, such as adding a buffer bin.
• The same equipment should be configured on the same floor as much as possible to facilitate operation and management.
• The layout of the equipment should be compact while ensuring safe operation, and there should be sufficient slide pipe angle to make the work flow smooth.

The process flow is an important part of process design and must meet the following principles:

• Meet the requirements for grain unloading, initial cleaning, grain feeding, storage and discharging operations in storage silos;
• Meet the requirements for equipment installation, operation and maintenance, and long-term use requirements for energy consumption, environmental sanitation, fire protection, safety, etc.;
• Have high flexibility, and the process should be reasonable and simple;
• The production capabilities of various equipment should be selected to match each other and be able to work continuously to create conditions for the mechanization and automation of the system.
• The technological process of the storage silos is determined based on the granary function, warehouse type, grain entry and exit methods, grain type, grain storage cycle and other conditions;
• Consider the needs of grain loading and unloading, transportation, cleaning, dust removal, measurement, storage, packaging, drying, inspection and testing, mechanical ventilation, grain condition measurement and control, fumigation and other process operations;
• The process flow should strive to be reasonable, simple and flexible;
• Granaries usually combined with feed mills; process operations should be considered uniformly; equipment production capacity should be coordinated and matched;
• Process design and equipment layout are an important part of the basic construction of storage silos. Different mechanical equipment can be used to form different process flows;
• Whether the selection and layout of process equipment is reasonable and whether the process is simple and smooth, the design is very critical.
• Reasonable technological processes can improve labor productivity, reduce food transportation costs, and improve energy efficiency.
• Vertical and horizontal conveying equipment are generally used for receiving, distributing and unloading grain in storage silos. When designing the process flow, the principle of one machine for multiple purposes should be followed to avoid setting up too many conveying equipment.
• When designing the cleaning and weighing process, it is generally a process of cleaning first and then weighing. For grains with high impurity content, a process of initial cleaning, weighing, and cleaning is set up.