How to evaluate whether a compressor oil is energy-saving?

To have both “gold and silver mountains” and “green water and green mountains” has become the goal pursued by manufacturing enterprises. To do a good job in energy conservation and emission reduction, enterprises need not only more energy-saving and environmentally friendly equipment, but also to add high-performance lubricating products to the equipment, which can not only reduce energy expenses for enterprises, but also reduce carbon emissions.

Air compressor is a device that converts mechanical energy into gas pressure energy. It is a compressed air pressure generating device. It can be used in different occasions such as providing air power, controlling automation devices, and underground passage ventilation. It is widely used in mining, textiles, metallurgy, machinery manufacturing, civil engineering, petrochemicals and other industries. It is an indispensable key equipment for the production and operation of many enterprises.

The function of air compressor is very powerful and can be called a “model worker” of enterprise production, but its energy consumption should not be underestimated. According to research, the power consumption of air compressor system can account for 15% to 35% of the total power consumption of gas-using enterprises; in the full life cycle cost of air compressor, energy consumption cost accounts for about three quarters. Therefore, the energy efficiency improvement of air compressor is particularly important for energy conservation and carbon reduction of enterprises.

Let’s take a look at the economic benefits behind compressor energy saving through a simple calculation: Take a 132kW screw air compressor running at full load as an example. 132kW means 132 degrees of electricity per hour. The electricity consumption for one day of full load operation is 132 degrees multiplied by 24 hours, which is equal to 3168 degrees, and the electricity consumption for one year is 1156320 degrees. We calculate based on 1 yuan per kilowatt-hour, and the electricity consumption of a 132kW screw air compressor running at full load for one year is 1156320 yuan. If the energy saving is 1%, 11563.2 yuan can be saved in one year; if the energy saving is 5%, 57816 yuan can be saved in one year.

As the power blood of mechanical equipment during operation, lubricating oil can achieve certain energy-saving effects by improving its performance, which has been verified in the application field of internal combustion engines. Through lubrication, the fuel consumption of internal combustion engines can be effectively reduced by 5-10% per 100 kilometers. Studies have shown that more than 80% of the wear and energy efficiency waste of mechanical equipment occurs in the stage of frequent start-stop, continuous high temperature and low temperature operation. The author believes that in order to reduce wear and improve energy efficiency through lubrication, it is necessary to start from these three key links.

At present, each OEM has its own bench test, which can more directly simulate the actual operating conditions of the equipment. The wear reduction and energy saving effect evaluated by the bench test is closer to the actual working conditions. However, bench tests are often costly, so the author believes that if the evaluation of wear reduction and energy saving effect can be advanced to the laboratory stage, it can save more costs and improve efficiency for the OEM’s bench test.

However, there is no special energy-saving effect evaluation method for compressor oil in the industry, but the author believes that with the help of many years of research results of internal combustion engine oil, the energy-saving effect of compressor oil in the laboratory stage can be evaluated through the following experiments.

1. Viscosity evaluation

Viscosity is a crucial indicator of lubricating oil, and there are many ways to express it.

Kinematic viscosity is the most common viscosity, which is an indicator that reflects the fluidity and internal friction characteristics of the fluid. The measurement of kinematic viscosity can be used to evaluate its fluidity and lubrication performance at different temperatures.

Brookfield rotational viscosity is a rotational viscosity measurement method pioneered by the Brookfield family in the United States, and its name comes from this. This method uses the unique relationship between the shear and resistance generated between the rotor and the fluid to obtain the viscosity value, evaluates the rotational viscosity of the oil at different temperatures, and is a common indicator of transmission oil.

Low-temperature apparent viscosity refers to the quotient obtained by dividing the corresponding shear stress by the shear rate under a certain speed gradient. This is a common viscosity evaluation indicator for engine oils, which has a good correlation with the cold start of the engine and can predict faults caused by insufficient pumping performance of the engine oil under low-temperature conditions.

Low-temperature pumping viscosity is the ability to evaluate the ability of the oil pump to pump to each friction surface under low-temperature conditions. It is a common viscosity evaluation indicator for engine oils and has a direct relationship with the cold start performance, start-up wear performance, and energy consumption during the start-up process of the engine.

2. Wear evaluation

Lubrication and friction reduction are one of the most critical properties of lubricating oil. Wear evaluation is also the most direct way to evaluate the anti-wear performance of oil products. The most common evaluation method is the four-ball friction tester.

The four-ball friction tester evaluates the load-bearing capacity of lubricants in the form of sliding friction under point contact pressure, including the maximum non-seizure load PB, sintering load PD, and comprehensive wear value ZMZ; or conducts long-term wear tests, measures friction, calculates friction coefficients, wear spot sizes, etc. With special accessories, end wear tests and simulated wear tests of materials can also be performed. The four-ball friction test is a very intuitive and key indicator for evaluating the anti-wear performance of oil products. It can be used to evaluate various industrial oils, transmission oils, and metalworking oils. Different evaluation indicators can also be selected according to the different uses of lubricating oils. In addition to providing direct anti-wear and extreme pressure data, the stability, uniformity, and continuity of the oil film can also be intuitively evaluated by observing the trend and line type of the friction curve during the experiment.

In addition, micro-motion wear test, anti-micro-pitting test, gear and pump wear test are all effective means to evaluate the anti-wear performance of oil products.

Through different anti-wear performance tests, the wear reduction ability of the oil can be directly reflected, which is also the most direct feedback for evaluating the energy-saving effect of lubricating oil.


Post time: Jul-01-2024