The Carousel Dryer - 30 years proven technology
This article is published in International Aquafeed June 2021
A proven technology with more than 30 years of history in the market
As there are a lot of dryer options available in the market. What
criteria are important for you to consider before making your selection?
If you are considering buying a new dryer and are looking for a dryer
with high reliability, easy moisture control, high energy efficiency,
and quick product changeover, then this article is definitely for you.
There are many different options, but this article will focus on the
CAROUSEL DRYER, proven technology with more than 30 years history in the
market.
The main function of a dryer is evaporating water. The evaporation must
uniformly take place and consistent in time, with minimum energy usage
and with the option for quick changeovers to minimize downtime and to
improve your overall drying process efficiency.
Figure 1. Airflow of carousel dryer
Figure 2. Target moisture changes in time
Reliable and Easy Moisture control
For the past 40 years, IDAH designs and manufactures equipment and
process lines for the aquafeed and pet food industries. In 2011, IDAH
started focusing on the Carousel Dryer technology. Our team of expert
Engineers have worked intensively to improve the Carousel Dryer
technology even further to increase the drying process efficiency. The
Carousel Dryer delivers outstanding performances when compared to
traditional dryers. The main advantages of choosing a Carousel Dryer
are:
• All the products undergo the same drying
conditions, resulting in very uniform and steady drying.
•
Optimal counter-flow heat transfer, resulting in low energy costs.
• Quick changeovers in a controlled way, lessen product
contamination.
The impact of moisture on your product
When choosing the correct dryer for your application, moisture control
should be one of the most important selection criteria. Moisture has
serious impact on your product quality and cost price levels, and
profits for your business One aspect of moisture control is uniformity,
together with drying result consistency–in-time will determine the
target average moisture content. The closer the average moisture to the
maximum moisture levels, then the less raw material are lost through
over-drying, generating more profit for your company.
In the cylindrical-shaped Carousel Dryer, the product is rotated 360° on
multiple decks and mixed by each drop when the tray gently tilts and the
material flows into the deck below. By rotating the product, the product
is situated in a fixed air stream, so all the product gets the same
drying conditions resulting in a product with uniform moisture and
consistent quality. In summary, uniform consistent drying is using less
raw material and reducing energy costs.
Improving dryer efficiency and saving energy costs
Water evaporation, or drying, is naturally a highly energy-intensive
process. The drying process has an unavoidable constraint to supply
enough energy for evaporation. The efficiency of a dryer will be
determined by the energy input about the amount of water evaporation.
The Carousel drying air passes the incoming product in this
multiple layer dryer in a counterflow direction to achieve maximum
heat transfer, resulting in a low exhaust air temperature. This in
combination with drying air recirculation will reduce the exhaust air
volume and improve energy efficiency.
Another option for energy conservation is the re-use of the cooling
air. Using the cooling air as make-up air for the dryer will reduce
the volume of exhaust air resulting in fewer odor control issues.
Plus, all the heat from the cooled product will be used in the dryer
for water evaporation. This combination will improve dryer efficiency
and saving energy costs.
The feed market trend is demanding to customize products, which
results in an increase of formula-changing frequency. This situation
demands producer to have a good and tight production schedule to keep
machine running optimally, while at the same time ensure no product
contamination using the FIFO (first in first out) principle.
Figure 4. Carousel dryer (Model TT-300-4-4) in customer site
Figure 4. Control system for carousel dryer developed by IDAH
Developing an operator-friendly control system
In 2020, IDAH incorporated a new moisture control system. This control
the system consists of:
Air volume and Temperature control - The
control philosophy of the dryer will be a crucial factor in the overall
performance. To get maximum profit for the uniform drying performance of
the Carousel Dryer, we control the energy absorption from the product by
controlling the air volume and temperature control.
Water evaporation calculations - the Carousel Drying System helps
companies accurately control their product moisture and keep track of
any changes in the parameters during production. This will help the
operator to achieve and maintain the target moisture quickly and
efficiently.
Energy efficiency indication - With the automatic
calculation, the operator can see the efficiency of the drying process
and take quick measures whenever the numbers are abnormal. Energy
control is drying control
Total control over energy consumption in your plant
Depending on your expectation of an ideal dryer, you may have to look
for different dryer options in the market. The dryer is a big investment
and also a big energy consumer in your plant.
IDAH considers all
of your process requirements, moisture uniformity, efficient energy
transfer, easy operation, and minimal down-time to select the suitable
Carousel Dryer for your industry.