We all know that milling is an energy-intensive sector. Energy is the largest operating expense item after raw material costs. When lifetime costs are examined, we face amounts exceeding investment expenses. For example, if we assume the investment cost of a flour mill of 200 t/day capacity reaches 5 million TL (2 million EUR) and its life time would be 20 years in average, then the annual depreciation cost will be 250,000 TL (100,000 EUR). The annual energy cost of such a company will be around 500.000 TL (200,000 EUR), twice the depreciation cost.
2. FEATURE FEATURE
Pneumatic conveying (negative pressure) controllable through extraction scales, can be
in a system where ground stock product is taken under control by extraction tracing and
carried, while volume of air moved changes, reporting through recording correct data.
static pressure varies with the square of the In new generation mills where the
speed, required power with the cube of number or the size of windows is reduced in
speed. order to prevent contamination, the choice
In summary, when volume of moved air with the lighting control and the energy
is reduced by 20 percent, fan speed is also efficient armature has gained importance.
reduced at the same ratio, whereas power To calculate milling capacity in the way
About the author:
consumption is down by 50 percent. not to run the plant at time zones with high-
Mr Tuncay Lamci is General
In pneumatic systems, removing vibration est energy cost and if demand is available, to
Manager of Integrated
by mechanic balance, setting product and increase capacity, they must be carefully ana-
Machinery Systems (IMAS)
stock speed by a right system design and using lysed since the latter will enable faster return
Energy saving in flour milling
minimum and wide angle elbow, optimising air of investment and if needed, be decided More information:
volume to be absorbed by clacks, setting fan immediately without delay. IMAS Integrated Machinery Systems
speed can be taken as first steps of a 10-20 It should not be forgotten that the way 2 Organize Sanayi Bologesi Lalehan,
percent saving in pneumatic system power. to compete in global markets and succeed Cad No:61, 42300, Turkey
by Mr Tuncay Lamci, General Manager of IMAS Integrated Machinery Systems, Turkey Conveying with blowers (positive pres- is through establishing energy efficient, effec-
Tel: +90 332 2390141
sure) is an expensive conveying method tive and lifetime systems, by considering
Website: www.milleral.com
that consumes same or more power than operating costs rather than investment costs.
pneumatic conveying. Amount
of power to be used changes
according to, correct design of
W
e all know that milling is an percent for mechanical conveying. For this conveyed with the remainder due friction, conveying line, periodic mainte-
energy-intensive sector. Energy reason, we will study energy savings under loading and discharge losses. nance and cleaning of blowers,
is the largest operating expense three main titles: Chain transfer systems require regular reduction of number of blowers
item after raw material costs. When lifetime • Methods of saving in motors oiling, whereas belt transfer requires regular by connecting lines required in
costs are examined, we face amounts • Conveying systems check, setting and replacement. the same area, dimensions and
exceeding investment expenses. • Automatic control and energy The right choice of often used V-belts speed of air locks to be used,
management according to the pulley groove, synchronised and distances between blades.
For example, if we assume the invest- replacement of multiple belts of the same The most convenient meth-
ment cost of a flour mill of 200t/day capacity Methods of saving in motors brand, parallelism of the pulleys, tension of od should be chosen among
reaches five million TL (two million EUR) Reducing the external load on motors, the belts are important parameters for the conveying systems.
and its life time would be 20 years on such as reducing air volume absorbed by energy cost. For example, with a 10
average, then the annual depreciation cost the pneumatic system or preventing leaks Reduction of motor losses, definition tonne per hour capacity; while
will be 250,000TL (100,000 EUR). The from compressed air system would thereby of size of motor being used in relation to a mechanic system consumes
annual energy cost of such a company will reduce motor load, which must be consid- the duty, choice of lowest motor for full 0.8kW of power for 20m verti-
be around 500.000TL (200,000 EUR), twice ered as the first step for the saving. load, high efficient motor choice rather cal conveying, this consumption,
the depreciation cost. The fact that efficient machines are cho- than a standard one at replacement would which is 4.7kW in pneumatic
Departing from this fact, the fastest sen according to the targeted production therefore reduce losses and enhance saving conveying, reaches 5.0kW in
way to reduce production costs is to have tonnage and they are used at full capacity opportunity. blower conveying.
A high efficiency motor of 90kW EFF1 In aspiration system, by
type running 18 hours per day and 300 days correct dimensioning, getting
per year at a plant, would yield 2500TL required airflow speed, prevent-
(1000 EUR) of energy saving in a year with ing loss and leaks and by using
actual energy costs. manometer filters tracking filter
Reducing the speed of motors means cleanness and avoiding unneces-
reduction in energy expenses. sary energy expenses is possible.
For example, in pneumatic systems
required air quantity for the transport of Automatic control and
stock product varies with the ambient and energy management
seasonal conditions; setting motor speed by In the aim of avoiding a
using variable speed drive would provide general misunderstanding in the
energy savings and would therefore return milling industry, it is needed to
the investment cost. re-emphasise on the purpose of
using automatic control in the
Conveying systems system and its benefits.
focus on energy costs right after raw mate- would reduce additional loads in motors We will study conveying systems as four Automation systems while
rial cost. and gears resulting from the system through types: Mechanical conveying, negative pres- they enhance system reliability
It would be possible to get energy saving, bearing condition and oil check in line with sure pneumatic conveying, positive pressure through level measuring, flow
through having maximum capacity usage in manufacturer’s advice. pneumatic conveying and dust collectors and measuring, scale equipments
overall process by 5-10 percent, using high The choice with motor drive arrange- aspiration. and failure warning switches
efficiency motors and total efficient main- ment is of paramount importance. Examples of mechanical conveying can and also thanks to the correct HALL 13
tenance by 2-5 percent, optimising air flow For example, as the friction losses will be be given as bucket elevators, screw and start and stop timing, they avoid STAND B71-C62
and avoiding leaks in conveying systems by lesser with direct drive methods, they will chain conveyors, in which some of the sav- unnecessary operations and
10-20 percent. work efficiently compared to chain or belt ing opportunities are use of products with make power saving independ-
While the process uses 50 percent elec- coupled systems. For bucket elevators, about proper bearings where the friction in these ent of operator mistakes.
tric energy for milling and grinding, 30 80 percent of the input power is directly machines are at minimum, regular protective The capacity, which can be
percent is used for pneumatic conveying, 11 attributable to the weight of material being maintenance, product choice at right capacity.
AD_SEA_ipakima.indd 1 31/01/2012 08:46
22 | January - february 2012 Grain &feed millinG technoloGy Grain &feed millinG technoloGy January - february 2012 | 23
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