As to discharge of condensate generated from an air compressor, problems of high air loss and high oil content have been identified, which leads to energy loss and environmental problems.
It has been known that a condensate discharge trap has significantly low reliability, including float type and time solenoid valve type.
In case of the float type trap, the nozzle is often clogged up (with impurities such as scale due to the narrow nozzle size of 0.7mm). The time solenoid valve type trap has huge air loss and short life span less then 1 year.
If a drain trap with zero air loss and effective discharge is applied to drain lines of an air compressor such as after cooler, air dryer, air tank, etc., any accident caused by a condensate leak can be prevented in advance.
Moreover, condensate generated from an air compressor is severely contaminated by the oil within the compressor and pollutants in the air and thus has a high oil (Normal hexane) content of nearly 2,000ppm(2,000mg/L), affecting the water quality of rivers and public health.
Oil is generated when air (including saturated water vapor) passes through a rotor for compressing (oil is input in order to reduce frictional heat), and oil of 2,000 ppm or more is discharged through drain traps of an air dryer, air filter, air tank, and so forth. (Acceptable standards for water contamination: 5 ppm or below according to the regulations))
Incomplete discharge of condensate generated from an air compressor can cause shortened life and failure of an air compressor, air dryer, receiver tank, production facilities, and so forth.
Air compressor : 100HP
Numerical values needed for calculating the amount of condensate – Compressor horsepower, working pressure, operation hours (daily, yearly), and machine efficiency
Ex) Compressor 100hp; working pressure – 7㎏/㎠; operation hours – 24hour/day, 330day/year;
Amount of condensate – 42,822 (ℓ) / year in case of 80% efficiency
|Section||Air Comp"||Air R/Tank||R/Dryer||Filter|
Compressed air, produced by high-cost power, is discharged into the air in order to discharge condensate.
How much is the yearly loss of compressed air in case of 7㎏/㎠ working pressure and 3π bypass valve opening?
0.6559 m3/min X 60 min X 24hour X 330 days
= 311,683 m3 X KRW 11 (1m3 air production cost)
= 3,428,513 KRW/year (per 1 Point)
3,428,513 KRW/year X 1 Point = 3,428,513 KRW/year
3,428,513 Won/year X 1 Point = 3,428,513 Won/year
Float trap requires frequent disassembly and cleaning due to the small nozzle diameter (0.7∅). (which explains the need for opening of a bypass valve)
Impurities in the float cause air loss because the nozzle can’t be closed.
Viscosity of oil reduces buoyancy of the float for an oil-injected compressor, and this requires frequent replacement cost.
Frequent failure occurs because of compression pressure directly applied to a solenoid valve.
A large amount of air is lost because condensate is discharged via time setting regardless of the amount.
Excessive noise is caused during discharge.
There is almost zero air loss, ensuring high economic efficiencyand fast recouping of initial investment.
Large-size drain prevents clogging, and self-restoration for an emergency mode improves safety.
A strainer within the product prevents collection of scale.
Automatic operation provides easy maintenance.
A variety of models are avaliable for smalland large capacity compressors air line.
Time to open a valve is calculated based on detection by a sensor.
An emergency mode begins after 60 sec if condensate is not properly discharged.
The emergency mode initiates the self-restoration feature, and the valve is opened for 5 sec per every 3 min as like time control valve temporally.
Setting Time : 5 sec per 5 min – condensate discharged for 1 sec and air lost for 4 sec.
: 12 times/hr x 4sec/time = 48sec/hr
Operation of 24 hr per day for 365 days
: 24hr/day x 48sec/hr x 365day/year = 420,480sec/year
Annual energy loss
: 7.2872㎥/min x 420,480sec/year ÷ 60sec/min = 51,069㎥/year
Production cost of 1m3 air: KRW 11
51,069㎥/year x KRW 11 = KRW 562,000
|Types of drain traps||Analysis|
|Time Control Solenoid Type||A large amount of air is lost because condensate is discharged via time setting regardless of the amount..|
|Float Type||The trap has low reliability and experiences frequent clogging due to the small nozzle diameter (0.7∅).|
|Manual Valve Open||Compressed air, produced by high-cost power, is discharged into the air in order to discharge condensate.|
|Drain trap types||Air loss calculation|
|Time Control Solenoid Type||KRW 562,000/1 point x 9 EA = KRW 5,058,000 / year|
|Manual Valve Open||KRW 1,686,000/ 1 point x 9EA = KRW 15,174,000 / year|
|Level sensor type(Drain Master)||Zero|
Application of an AI (artificial intelligence) electronic sensing system
Discharge of condensate only (Zero air loss)
No clogging (easy maintenance and high efficiency)
Low labor cost and improved cleanness
Reduced power cost, low replacement cost, and no noise
No need for frequent disassembly and replacement
Extraction and treatment of pure oil
*Reduction of the treated amount by 98%
*Condensate of 5ppm or below only discharged / regular drainage
Hence, regarding an oil injection compressor, condensate causes frequent clogging of a drain trap that lowers efficiency, affects air quality, results in high energy loss due to air loss, and contaminates water because of high oil content.
Installation of a semi-permanent drain trap and oil-water separator, which discharge condensate only without energy loss, can maximize efficiency in terms of operation and maintenance.