Refining companies should be obliged to enhance the quality of their substandard products, namely gasoline, diesel and mazut, the head of the Board of Directors at the Iranian Oil, Gas and Petrochemical Products Exporters Union said.
“The main products of the National Iranian Oil Company do not comply with international standards as they contain a huge volume of toxic sulfur compounds that have made air pollution in large cities worse,” ILNA also quoted Hamid Hosseini as saying.
NIOC’s mazut, which is delivered to power plants as an alternative feedstock to generate electricity, contains as much as 35,000 parts per million (ppm) of sulfur, while the standard ppm should not exceed 500 ppm, he added.
“Nowhere in the world such low-quality fuel is allowed to be burnt,” he said, adding that the substandard mazut cannot be used even in ships as fuel.
Referring to diesel, he noted that the diesel produced in Iranian refineries has a very high sulfur level of 15,000 ppm, which must not surpass 500 ppm to be compliant with international standards.
According to the official, some refineries blend harmful chemicals into gasoline to raise their production capacity, which has impaired the fuel quality so severely that even Afghan officials are not willing to import them.
Of the National Iranian Oil Company’s total gasoline production of 100 million liters per day, 50% are compliant with Euro-4 and 5 emission standards, but the rest [50 million liters/d] is low quality fuel and contains chemicals like benzene, raffinate, naphtha and other aromatic compounds.
Although adding such chemical products can increase the volume of the fuel, it adversely affects its quality and converts it to Euro-3 fuel that could have a detrimental effect on engine performance, human health and the environment, he added.
Hosseini said burning this kind of low quality gasoline has been forbidden even in under-developed countries.
Aromatic Compounds
Referring to exports statistics of some local petrochem companies, including Nouri Petrochemical Company in southern Bushehr Province, he noted that the firm sold close to 32 million tons of its benzene, raffinate, naphtha and other aromatic compounds in the international markets in 2021.
“However, this year’s figures have dwindled noticeably, which means the company’s products are being used in domestic refineries to produce gasoline compliant with Euro-3 emission standards,” he said.
The removal of sulfur compounds from mazut is crucial for reducing air pollution, the Thermal Power Plants Holding Company’s deputy for environmental affairs said.
According to Sanaz Jafarzadeh, the head of Environment Protection Department at the Thermal Power Plants Holding Company, if the Oil Ministry supplies power stations with quality (low-sulfur) liquefied fuels, there will be much less air pollution.
NIOC does not care about desulfurization and the mazut delivered to thermal power plants does not comply with environmental standards, she added.
Desulfurization is the process of using hydrogen gas to lower the sulfur content in hydrocarbons, which reduces the emissions of sulfur oxides responsible for acid rain. Countries across the globe have put strict regulations in place to limit the sulfur content in fuels.
The state-run NIOC is supposed to supply power plants with mazut whose sulfur content must not be more than 0.5%, while the current level is 3.5%.
Maintenance Costs
The official said high-sulfur mazut is not suitable for power plants, as it doubles maintenance costs, increases water consumption and reduces output.
Most thermal power plants are gas-powered and the use of liquefied fuels has long-term adverse effects. The use of diesel and mazut instead of gas in power plants and other industries increases greenhouse gases.
As more liquid fuel is burnt, higher volumes of toxic fumes are released into the atmosphere making a bad pollution situation worse.
When power plants do not receive adequate natural gas due to high household consumption, they need to either reduce output or burn liquid fuel to avoid outages.
The increased utilization of fossil fuels and industrialization in most parts of the world have led to a remarkable increase in the atmospheric sulfur concentrations. Pollution released by the use of petroleum-based fuels immensely deteriorates air quality despite regulatory and technological advances in place.
SOx, NOx and particulate matter are constantly emitted into the environment, which affects public health, the area’s ecosystem and the wellbeing of people living in urban areas.
Sulfur dioxide, the immediate sulfur compound found in the lower atmosphere after fuel combustion, plays a major role in the formation of acid rain, smog and particulate aerosols.
