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Pulverised Air Dryer (PAD)

An exemplary ‘non-thermal’ biomass dryer that can pulverise, micronise and dry malleable material

Designed to dry many waste products without the use of an external heat source

Improving Waste Treatment and Minimisation

Sludge is an unavoidable waste product from many differing industries and the world today is producing mountains and lagoons of waste annually without proper equipment and resources for its safe and/or economical disposal. Dewatering and drying is a vital part of sludge treatment, which reduces transportation and disposal costs, while at the same time limiting adverse effects on the environment. The Pulverised Air Dryer (PAD) system is a unique, robust and far-reaching treatment technology for the waste management sector, which can cost-effectively dry materials from 80% initial moisture content down to 10%. PAD does not use high thermal temperatures, as in most commonly used drying processes. Other technologies, such as thermal oxidising, dry the product for waste disposal purposes, whereas the PAD system not only dries the product more efficiently, using high velocity air, but also provides end product value. The moisture is not ‘cooked’ out, thus producing a superior and saleable by-product.

The PAD system currently targets the following waste production industries:

ü Ethanol production

ü Seafood processing

ü Municipal sludge

ü Paper mill sludge

ü Animal waste

and there are numerous other industries where application of the PAD technology could be effective.

Industry tends to dispose of its waste products by burying and/or burning and the costs are high (transportation, landfill, hydrocarbon fuels, etc). The PAD system can dry these waste products without an external heat source, by utilising high velocity air, and without creating emissions in excess of recognised environmental protection standards.

As examples, paper mill primary sludge at 35% solids can be PAD dried to 80% solids and the protein value of PAD dried distillers grains is 35-38%, with moisture levels in the final product of 10-14%.

From this ……… to this

The Technology

The raw material is combined with a proprietary feeder arrangement into a high velocity air stream. The raw product accelerates to super-cyclonic speeds before reaching the first cyclone in line where additional pulverising takes place. As the raw material passes through subsequent cones of larger sizes, the pulverised product gives up its moisture until its discharge from the final conditioning cone. Auxiliary air is furnished along the line to aid in the drying process. The high velocity air increases in temperature, but does not raise the temperature of the raw product to create any detrimental changes to the end product. Because external heat from various hydrocarbon sources is not part of the process, the emissions from the process are proved to be significantly below allowable international pollution levels.

Features

When compared to other available dewatering and drying technologies, the PAD system offers unique features:

q Utilisation of high velocity air, with no external heat source required

q Odourless processing

q Easy expansion to higher production levels

q Versatile assembly that can be installed in a variety of locations without extensive modifications

q Single or multiple feeding sources which can be customised to the needs of the producer’s raw material

Key Benefits

The Pad system can make an important difference to the viability of sludge treatment, allowing previously prohibitive waste treatment to become economically attractive while also improving environmental protection:

q Radically improved dewatering and drying performance

q Easier and significantly more efficient waste disposal, reducing cost and landfill requirements

q Reduced operating costs

q Potential for value-added usable by-products

q Amortisation of capital cost of equipment in reduced timeframe

q Less hazardous to operators as no boilers or burners are required

q Meets and exceeds environmental protection emission standards

Professional engineers and technicians, with many years of experience in their field, have developed the PAD system. Results have already been impressive and continuous ongoing development ensures that the system can be modified to suit a range of differing sludge applications.

We have found no machine or process currently in operation that compares with the PAD systems in terms of design or production capacity. In addition, this system creates a tangible ability to create a profit source, while at the same time reducing pollution of our fragile environment. Industries, such as ethanol production, pulp and paper and other industrial operations, where the increase in sludge and slurries are becoming a major environmental problem, can turn a cost for disposal into a beneficial profit centre.

Martin Parr

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