Experts tested autogas quality
The autogas market is in fever. The prices for popular fuel (the country fleet fueled with gas is about 30%) show a rabid turbulence. At first, in just a week, "blue" fuel has risen in price almost twice, then the price tags have decreased by 30 percent. At the same time, many networks felt a shortage of resources, and the factor of supply disruption has led to the price rally. Besides, many experts say that the lack of resources in the market is accompanied by a sharply increase in the amount of the "shadow" product of dubious quality. In last year's study, experts found a mixed picture; there were many violations, especially on the part of illegal sellers. The specialists of the Institute of Consumer Expertise studied the current situation.
Recently, many motorists have complained about the quality of gas in social media, accusing the largest network of filling stations. Therefore, the main experts focused on a number of all-Ukrainian filling stations (Shell, OKKO, WOG, BRSM and others), large networks of the capital city and the regions (KLO, Luxwen) and a number of "barrels", i.e. illegal gas stations. The experts collected samples into a special sampler, whereupon the samples were brought to the laboratory. Unlike last year's test, this time both filling network and "illegals" released fuel for analysis without any problem. However, the "barrels" released fuel subject to non-issuance of a fiscal receipt only, and we learned the reason after the laboratory tests.
How much is "blown in"?
Gas filling accuracy is the value most criticized by drivers. Many motorists measure the runs and complain that the volume of the gas filled is greater than the cylinder capacity. According to the standards, the shortage may be max 1%, but it is quite difficult to achieve such a result in the barrel. However, in fact, the results were excellent. All network gas stations have a filling accuracy above 97%. The most accurate filling was shown by PowerGas at Shell gas stations, 99.0%, and BRSM-Nafta, 98.5 percent. The "illegals’" sin is underfilling. According to the insider information, the 10% underfilling is a common practice. Some particularly greedy "mates" manage to cheat the drivers by 20% of the amount indicated on the counter. Also, the underfilling can happen without malice, because "illegals" save on timely servicing of columns. In the end, the consumer enjoys a much lower price, but drives lesser kilometers.
In the laboratory
In the laboratory, the samples were tested for compliance with GOST 27578 "Hydrocarbon Liquefied Gases for Motor Vehicles" in terms of the "Chemical composition." As is known, automotive gas consists of a mixture of propane and butane, and other hydrocarbons (isobutane, propylene, ethane, ethylene etc.). For different seasons, the quantitative content of the mixture may be different. In summer it is about 40:60 (propane to butane), and vice versa in winter - 60:40. The more propane the gas contains, the higher is the vapor pressure, and the better is the starting quality and performance of the fuel injection equipment during the winter.
One of the main issues is also a liquefied gas grades. There are two main ones, BPA (propane butane automotive) and PBTM (propane butane technical mixture). What is the difference? The first grade is the purified gas adapted for use in cars, and the second is more "dirty", intended for domestic use (e.g., heating). And here we revealed unpleasant surprises.
European standard EN 589-2008, in section terms, treats the automobile liquefied gas as a gas containing a small amount of unsaturated hydrocarbon (propylene, butenes and pentanes (pentenes). Ukraine applies GOST 27578-87 setting the limit of unsaturated hydrocarbons as a max 6%. In the samples taken at the illegal filling stations, they exceeded the norm a lot, reaching 11%! Based of these data, the fuel can not be classified as automotive. Besides, the gas from the "barrel" did not contain enough propane, i.e. 33%, while the standard is min 50 ± 10%. This will not cause a significant harm to the car, but the consumption of such a gas would be much greater.
According to the requirements, PBTM may contain 1.6% of the liquid residue, while BPA may not contain the residue. Besides, the permissible limit of the sulfur content in BPA is lower than in PBTM (and according to EN 589 requirements, it is max 50 mg/kg).
The presence of liquid residue in PBTM when used in vehicles leads to the residue accumulation in tanks, clogging of filters, and fuel injection equipment malfunctions. The presence of unsaturated hydrocarbons leads to an increase of pollutants in the flue gases. The increased sulfur content leads to a reduced service life of catalytic converters and environment pollution with sulfur oxides. The presence of mercaptan sulfur leads to increased corrosion of the fuel injection equipment parts.
In general, all the big networks have passed the test, showing good results. The best value was shown by Power Gas sample at Shell filling stations, 58 propane and 39 butane. This ratio ensures a more complete combustion of the mixture, and, therefore, will provide a dynamic while maintaining the driving economy. BRSM-Nafta automotive gas ranked second with a ratio of 52:44. By the way, the sample from Shell, Power Gas, was the most "pure". It contained only 0.10% of propylene. Also, OKKO sample showed quite good results due to a well-balanced composition of components and a low propylene content.
And one more important parameter is the gas density. The larger it is, the greater the mileage per tank filling, ceteris paribus. The highest values by this parameter were shown by samples from Luxwen and Shell networks.
A dry residue
In general, the situation with the quality of automotive gas was not so critical as price fluctuations. Apparently, the networks sell high-quality fuel of Ukrainian, Belarusian or Russian origin. It remains to wish that the supplies were rhythmic, and the market did not experience shortages. Then the prices will go down, because the competition in this segment is very high.