This report is based on actual data from gasminers installed at local gas stations in Indonesia from November 1, 2024. It provides evidence of how much vapor is actually emitted at gas stations and how well gasminers liquefy vapor and recover it as gasoline.
Volatile organic compounds (VOCs) emitted from gas stations are causing serious problems such as air pollution and resource loss. Gasoline sold at gas stations has high evaporation pressure, so there is no proper way to suppress the emission of vapors (VOCs), so the best way is to recover and liquefy it. In this study, we use the data obtained by directly installing and operating a special vapor recovery and liquefaction device called GASminer at gas stations. Based on this data, we measure the amount of vapor emitted and present empirical data. In addition, we aim to contribute to environmental protection and the realization of carbon neutrality by reducing VOC emissions.
1.1 Gas station
The measurement target is PT. CITA LINI PERSADA gas station.
This gas station operates a total of five tanks: three Pertalite (Ron 90) tanks, one Pertamax (Ron 92) tank and one Pertamax turbo (Ron 98) tank.
This gas station is not equipped with Stage I recovery equipment, nor Stage II recovery equipment. It is known that most gas stations in Indonesia do not have such recovery equipment.
1.2 VRU(Vapor Recovery Units)
A vapor recovery units(VRU), GASminer, was installed at the target gas station and the amount of gasoline recycled each day and loaded into the underground tank was measured.
GASminer is a VRU with a cooling capacity of 2.8RT and a 5 HP compressor, and is manufactured by Emglobal CO., Ltd. in Korea.
The characteristics of this equipment are that it can recover and liquefy more than 95% of the vapor continuously discharged for 24 hours with a small power consumption. In particular, it has the advantage of being equipped with an oil-water separation system
that can prevent water from flowing into the gasoline storage tank. Therefore, it can be said to be a suitable actual measurement equipment for this study.
1.3 Measurement Method
Gasoline was discharged daily and the amount was measured manually.
1.4 Measurement Period
The measurement period is from November 1, 2024 to May 11, 2025.
The time series data measured daily are as follows. Given that the daily measurements show a large difference, it can be assumed that they are closely related to the weather conditions such as temperature, humidity, and solar radiation on the day before gasoline discharge.
By plotting the 7-day moving average and the 15-day moving average based on the data, we can see that it is within a stable range.
The monthly statistics are as shown in the table below. The small filling volume in May is the result of reflecting only data from May 1 to 10.
The recovery rate, i.e. the ratio of total recovery volume to total filling volume, was found to be 0.124%. The monthly recovery rate was visualized in a graph as follows.
As can be seen from the graph, there was a continuous decline from December to March, but then a rebound in April and May. This seems to be related to the drop in temperature and increase in humidity due to the rainy season in Indonesia. It is necessary to refer to the actual precipitation data for the period.
The amount of gasoline sold by a gas station each day is not constant, and the amount of gasoline loaded into the storage tank also varies depending on the sales volume. The daily loading volume is very widely distributed, from a low of 16,000 liters to a high of 88,000 liters. However, most loadings occurred between 32,000 and 56,000, which means that they are very large-scale gas stations.
*Some outlier data were excluded. There may be actual recording errors, and data after water discharge is structurally underestimated to underestimate the recovery rate.
As can be seen from the recovery rate, which is evenly distributed between 32,000 and 56,000 liters, the VRU device is demonstrating sufficient performance to analyze the vapor discharged from the gas station. In addition, if the vapor discharge amount is calculated as a ratio to the loading amount, it can be seen that there is no correlation between the loading amount and the recovery rate.
Comparison of the graphs of recovery rates and temperature and precipitation over the same period showed that there was a significant correlation between the temperature decrease or increase during the rainy season and the trend of recovery rate fluctuations. Based on the recovery rate in November and December, when the rainy season is just beginning, a value of 0.13% or more can be expected during the dry season.
Next, the amount of water recovered during the vapor recovery process was analyzed. At gas stations without Stage II recovery facilities, there is no process of injecting the vapor recovered from the vehicle tank into the underground storage tank when the customer refuels the vehicle. Therefore, the pressure in the storage tank decreases while refueling the vehicle, and as a result, outside air is drawn into the underground storage tank.
The outside air flowing into the storage tank inevitably contains a significant amount of water vapor, and it can be expected that there will be a large difference depending on the climate characteristics. The table and graph above show the amount of water recovered compared to the amount of gasoline recovered, and it shows that a relatively large amount of water is regenerated from water vapor during the rainy season.
The table below shows the data on the quality of gasoline recovered from PT. PERTAMINA in Indonesia. What can be seen from this data is that when the vaporized gasoline vapor is liquefied, the components are not the same as the gasoline before evaporation. There were differences in density, vaporization pressure, and octane number [RON (Research Octane Number)].
* Reid vapor pressure (RVP) is a common measure of the volatility of gasoline and other petroleum products. It is defined as the absolute vapor pressure exerted by the vapor of the liquid and any dissolved gases/moisture at 37.8 °C (100 °F).
Gasoline obtained by liquefying the vapor is light (low density), evaporates easily (high evaporation pressure), and has low knocking resistance. This is a natural result since the vapor evaporated in the storage tank is collected and liquefied. Therefore, gasoline regenerated in this way should not be used as automobile fuel.
This is because although the RON value indicating knocking resistance is 89.9, which is almost close to the minimum standard of 90.0, the evaporation pressure is high, so knocking can occur.
However, there is no problem with reuse. This is because the recycled gasoline can be injected into the storage tank and diluted. In [2.1 Daily Recovery Rate], the recovery rate was confirmed to be 0.13% on average. Therefore, not only is the dilution rate in the storage tank only 0.13%, but it should be injected and diluted so that the components of the gasoline waiting to be sold in the storage tank are considered to be more in line with the fuel oil quality standards.
Then, let's calculate the economic value of gasoline recovered from vapor and liquefied. The price of gasoline in Indonesia is usually about $ 0.64 per liter (pertarite). Based on this, if we calculate the value of gasoline recovered over a certain period of time on a monthly basis, it is as shown in the table below.
Since the annual recovery volume and value are estimated based only on data during the rainy season, the actual regeneration value for one year including the dry season will increase by 5-10%.
For a gas station selling an average of 48,000 liters per day, this would mean an annual profit of $ 13,789. This means that over 15 years, fuel resources worth $ 206,842 will be emitted into the atmosphere, which not only causes enormous economic losses but also proves that a huge amount of air pollutants are emitted.
* The GASminer manufacturer provides a total of 15 years of product quality warranty, 3 years free and 12 years paid.
Based on the annual estimated value in Table 7, the amount and value of gasoline recovered according to daily sales can be calculated as follows. For example, if 32,000 liters are sold per day, the annual recovery amount is (32,000*21,564)/48,000=14,364 liters.
Since the value of recovered gasoline becomes the profit of the gas station, naturally, the higher the daily sales amount, the greater the profit. If the daily sales amount is more than 30,000 liters, the annual profit of $ 9,193 and $ 137,894 in 15 years can be realized.
The profit that a gas station can realize is closely related not only to the recovery amount but also to the gasoline price in the area. In other words, it is proportional to the gasoline price, meaning that if the unit price per liter doubles, the profit also doubles.
The amount of vapor emitted from the gas station was measured to be 0.124% of the gasoline filled in the underground storage tank. The measurement period corresponds to the rainy season in Indonesia, and if we refer to the data from November and May, which can be considered as the dry season, it is reasonable to estimate that it is more than 0.13% on average per year. In addition, it was confirmed that the amount of water regenerated from the vapor was large due to the high humidity during the rainy season and for a considerable period after the end of the rainy season. Therefore, it is very important that the VRU used to suppress the emission of vapor must be able to separate water.
It has also been confirmed that liquefying the vapor and regenerating it into gasoline can provide enormous economic benefits. The amount of vapor generated is closely related to the climate, so the amount generated will be the largest in areas with high temperatures and dry temperatures throughout the year. Additionally, in areas where the price of gasoline per liter is high, it is obvious that the economic feasibility will also increase significantly along with the increase in the amount generated.
Therefore, it can be said that it is a natural duty to make efforts to prevent air pollution while recovering the vapor and liquefying it and obtaining economic benefits at the same time.
Contact
Tel. +82-10-2246-5729
Mail. limyh@emglobal.biz
Addr: Incheon, Korea
