Human sense of smell is the most effective "device" for detecting gas leaks. And to help him are called special additives with an unpleasant odor, which are mixed with "blue" fuel. Agree, they are rarely remembered and even less known. Are you wondering what the smell for gas is called and why should it be added to the gas?
We will help you understand these issues - the article discusses the reasons for adding aroma to gas and the features of these smelling substances. The norms according to which odor is added and safety measures for the use of odorants are given.
The content of the article:
- Requirements for Smelling Gas Additives
-
Features of a mixture of natural mercaptans
- Norms and restrictions when adding an odorant
- How does the scent addition process work?
- Safety measures when working with mercaptans
- Conclusions and useful video on the topic
Requirements for Smelling Gas Additives
The two most unpleasant characteristics of natural gas for consumers are the lack of color and odor. The reason is that its leak is a direct route to
explosion or fire. It is almost impossible to detect a leak of a colorless, odorless substance.Therefore, the only way out is to use odorants. What these substances are is stated in TU 51-31323949-94-2002, developed by VNIIGAZ LLC, which is a division of Gazprom. Based on the provisions of these conditions, odorants are produced.
The paradox of the situation with substances that should give gas a smell and save lives is that organic, but poisonous compounds are used for this purpose
And the specified technical condition says that odorants are intensely smelling substances or their combinations that are added to natural gas. Moreover, only in small concentrations in order to give a specific (unpleasant) warning odor.
This is done to make it easier to detect gas leaks when the gas concentration does not reach the lower explosive limit. That makes it possible for any person to identify a fuel leak at a concentration of about 1% of the total volume of the room. This provides a margin of time in order to prevent negative consequences. Since an explosion can occur when the gas concentration reaches 5% of the total volume of the room.
We recommend that you familiarize yourself with the best ways to check for gas leaks at home.
The use of odorants increases the cost of gas. Therefore, the mixing procedure is carried out in distribution networks before the very supply of the energy carrier to consumers.
GOST 5542-2014 regulates what should be household gasthat is supplied to consumers. Actually, it can be considered the main profile document. Since in the Russian Federation the question of what needs to be added to natural gas to give it a specific unpleasant smell is not completely regulated.
The only exception can be considered a document WFD 39-1.10-069-2002. This is an internal document of Gazprom. It describes in most detail the odorization procedure, which substances are used for this, as well as safety requirements when working with odorants.
Since the odorant has a pungent odor and, moreover, is poisonous (in a concentrated state), its storage and transportation is carried out in special tanks, barrels
In addition to a specific odor, odorants should have a number of other characteristics:
- exhibit chemical and physical stability in a vaporous state when mixed with gas and when transported through a pipeline;
- do not adversely affect the materials from which the pipes are made and any other structural elements of gas pipelines - this is necessary in order to exclude a decrease in the operational characteristics and service life of pipelines as a whole and of its individual structural elements;
- be concentrated - this will make it possible to reduce the amount of substance used;
- have little toxicity - this requirement applies exclusively to the working concentration of odorants.
It should be noted that not a single commonly used chemical substance meets all of the listed requirements today.
But the most suitable are the so-called natural mercaptans, and, to be precise, their mixtures. The smell that consumers feel every time they turn on the gas equipment.
Features of a mixture of natural mercaptans
A mixture of natural mercaptans is an organic compound. Mercaptans have pronounced aromatic properties, therefore they emit an unpleasant and pungent odor even at low concentrations.
The odorant production method is based on alkaline extraction, that is, the separation of mercaptans from stable gas condensate, as well as its mixtures with oil. As a result, a primary product is obtained, which is called SMP - a mixture of natural mercaptans.
The photo shows a special vehicle designed to transport the odorant. It belongs to the new generation and has increased safety. And Gazprom is investing in the development of such vehicles.
The secondary product is SMP-1, which is a drained NSR. Moreover, both types of odorant are suitable for mixing with gas. So it is said in the above TU.
Mercaptan blends are supplied in liquid form. It is transparent and has an extremely unpleasant and pungent odor. In addition, SMP, as well as its derivative SMP-1, is hazardous substances of hazard class 2. They are classified as flammable products. Therefore, the rooms for odorization and storage of the mixture must be equipped in accordance with the requirements for rooms of category B-1a.
Mercaptans became the main odorant back in 1984. Currently, they are produced at the Orenburg Refinery (part of Gazprom's structure).
Norms and restrictions when adding an odorant
As mentioned above, mixtures of natural mercaptans are introduced in small quantities. In practice, this is the case, since only 16 g of these chemicals can be provided for every 1000 m³ of natural gas supplied to consumers.
Today GOST 5542-2014 limits the density of mercaptan sulfur in the odorant composition to 0.0036 grams per cubic meter. Although the said document states that in some gas pipelines the amount of this substance in the composition of odorants may be somewhat larger. However, the exact figure is not given.
The reason for the limitation is that sulfur reacts with iron oxide formed in as a result of corrosion of steel pipes of main gas pipelines and a significant part of distribution pipelines. And this feature often leads to a significant reduction in the amount of odorant used, which makes their use almost useless.
In order not to be afraid of gas leaks and the disastrous consequences to which they can lead, experts recommend installing leakage sensor with shut-off valve - such a device will not only detect a leak in a timely manner, but also immediately cut off the gas supply to an apartment or house.
How does the scent addition process work?
The specified substance, which serves to impart a specific smell to the gas supplied to consumers, is mixed with it using special installations. They are used to equip gas distribution stations.
The photo shows an odorization unit used at one of the Russian gas distribution points. And not a single cubic meter of gas supplied to the population passes by.
There are 2 ways to odorize:
- gas saturation with vapor natural mercaptans;
- drip injection the required amount of odorant into the gas stream.
Both types of installations are successfully used at domestic gas distribution stations. But the most demanded is the equipment with the help of which mercaptans are injected into the drip. The reason is its simplicity and cheapness.
The odorant delivery procedure is performed using a dropper. And the method is based on the constant value of one drop of liquid. So, in the case of mercaptans, the indicated volume is always 0.002 g.
To prevent malfunctions in odorizing installations, the consumption of a substance that gives a specific odor to the gas is constantly monitored.
On the territory of the Russian Federation, 2 large factories are engaged in the development and production of odorizing devices. Since the country needs a large amount of such equipment, moreover, reliable and safe
The only automated way of mixing mercaptans and energy carrier is the use of bubbling installations.
Despite the active use of odorants, the methods of their introduction into the gas stream are considered obsolete. As a result, experts predict the appearance in the coming years of fundamentally new mixing methods based on methods of accurate rapid analysis of the situation.
Safety measures when working with mercaptans
All varieties of odorizing substance belong to 2 hazard class. The main component of the odorant is ethyl mercaptan - contains a large amount of sulfur. Usually it is not less than 37%, as indicated by TU 51-31323949-94-2002. And such a feature can lead to negative consequences for the human body, and even death (if the substance enters the body).
Therefore, when interacting, storing, transporting this substance, it is necessary to observe safety measures, which is dedicated to NS. 5.5 WFD 39-1.10-069-2002.
Safety measures when handling mercaptans should be known, if only because it happens as shown in the photo, where in the foreground are seen the barrels thrown by careless gasmen, in which the odorant. And they are dangerous. For example, the soil on which a mixture of natural mercaptans has been spilled must be treated twice with special solutions.
According to these requirements, when in contact with a concentrated odorant, special clothing, personal protective equipment - a gas mask, rubber boots and gloves, rubberized aprons should be used.
At the same time, exhaust ventilation must be turned on in the room with the odorant. If a toxic liquid or its vapors get on the skin, their remnants must be washed off with a significant amount of warm water, if possible with soap.
If the mercaptans have caused irritation of the mucous membranes, then the affected areas should be washed:
- warm water;
- 2% baking soda, if there is one.
If the respiratory organs are affected, then the victim should be evacuated from the room. And his well-being will improve fresh air and peace. And if the respiratory system is damaged, it is imperative to call a doctor.
The photo shows a dump located near the Tomsk railway station, where, through an oversight, the containers with the remnants of mercaptans were thrown. As a result, for a long time, their smell frightened residents of the surrounding areas.
Although many experts criticize certain points and provisions contained in the departmental instruction of Gazprom on measures safety during storage, transportation, use of odorants, but consumers should be prepared for various situations.
The fact is that various incidents and accidents with odorants are quite common. For example, in 2012 their smell led to a great commotion in Penza. A few years ago, there were incidents in the Leningrad region, and just a couple of years ago, the Ministry of Emergency Situations had to urgently evacuate a tank with mercaptans from the northern capital itself.
In 2017 panic arose in the small Ukrainian town of Lisichansk, when gas workers slightly exceeded the norm established for mixing odorant and gas. And at the end of 2018 Rospotrebnadzor revealed the presence of a mixture of mercaptans in the atmosphere of Nizhnevartovsk. Moreover, in the very center of the city. As it turned out later, someone had buried a barrel with this substance, and during excavation work it was damaged.
But an ordinary gas consumer should not be afraid - in practice it is difficult to suffer from the effects of an odorant, because its concentration in the supplied fuel is negligible in order to cause a visible reaction in household use.
Still, it should be remembered that if the smell of SPM has become more acute, then you need to turn off all gas appliances, open the windows, leave the room and report the incident to the emergency services of the gas station.
If a pungent aroma penetrates from the outside, then you need to tightly close the windows and try not to go outside. In addition, you need to call the Ministry of Emergencies or Gorgaz.
We recommend that you familiarize yourself with the procedure for detecting a leak in apartment or entrance.
Conclusions and useful video on the topic
The video attached below tells about the incident with mercaptans in Penza.
Odorants give gas to gas and significantly reduce the likelihood of accidents. But organic substances used as danger signaling devices are potentially hazardous to health and are used due to the fact that today there is no alternative.
As a result, consumers should have knowledge not only about whether the gas supplied has an odor, but also the skills to mitigate the effects of poisoning with these substances.
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