HED - HIGH EFFICIENCY DIGESTER

The High Efficient Digester (HED) is an anaerobic digestion system, available in different sizes depending on the requirements of the farm.

BIOGAS TECHNOLOGY:

Biogas is generated by an anaerobic digestion process, which is the decomposition of organic matter in absence of oxygen by different bacteria. Biogas is produced during three phases:

Hydrolysis:

Fermentative bacteria convert insoluble material as carbohydrates, fats and proteins into soluble substances (smaller molecules). However some fibrous material cannot be fermented and can be accumulated in the digester or pass though the digester intact.

Acidification:

At this stage, the products of the hydrolysis are converted by acetogenic bacteria into acetic acid, hydrogen and carbon dioxide.

Methane formation:

the products of the acidification stage are converted into biogas by the methane forming bacteria.

The biogas produced has around 60% methane, 40% carbon dioxide, and trace of water vapor, hydrogen sulfide and ammonia. This biogas can be introduced into a CPH unit (Combined Heat and Power), to produce electrical energy and thermal energy.

Anaerobic digestion process can reduce the odors of liquid manure. The liquid after the digestion, known as digestate, is equal in volume to the initial substrate, but low in odor and with a high content of nutrients, therefore can be used as fertilizer or be dried to decrease the volume and obtain better storage conditions with high nutrients content.

BIOGAS PLANT DESIGN:

The system is formed by:

• Pre-dump (for manure storage)
• Main Digester
• Follow up digester
• Storage tank
• CHP Unit

SYSTEM CHARACTERISTICS:

• Every fermenter has only one big mixer. Frequency controller(15kW)
• Mixing system: Giant paddle mixer (7 turns/minute)
• No pre-dumps (only small storage tank for the daily manure)
• All digesters have two layer plastic
• Gas storage and desulphurization inside digesters
• One central pump
• Valves at pipes are guided by air
• Temperature digester: 40°C
• Computer control system
• Low energy self consumption (less than 5%)
• CHP Unit (150-700kWe)

DIMENSION OF THE SYSTEM:

An important advantage of the HED, is that can be constructed in different sizes, depending on the availability of the substrates and requirements of the farm.

• Capacities from 150 kWe to 700 kWe

SUBSTRATES:

High Efficient Digester (HED) is able to work with several substrates as:

• Animal manure (swine manure, cattle manure, poultry slurry)
• Energy crops (maize silage)
• Food waste (food waste from cattle)
• Organic waste