Determination of the number coming into the room gases
Determination of the number entering the premises of gases, vapors and aerosols with accuracy sufficient for practice is possible when the harmfulness of the product of a well-studied chemical reactions in the case of evaporation of the solvent in the room PLI evaporation from open surfaces. But in many branches of chemical technology, when the reactions occur in a closed apparatus, with breaks of fugitive gases during transportation and storage of incoming air pollutant in almost incalculable.
Sometimes the amount received by the air pollutant is determined according to the material balance of production. If you know the ongoing reaction or there are practical data outage, stupor, evaporation of the processed materials, according to the technological balance may determine the amount of pollutant emitted.
The amount of liquid (not water) that evaporates from the free surface, can be approximately determined by the formula
G - M (O, 00035 - \ - 0.0008 y) PF [kg / h], (21)
where M - molecular weight of the evaporating liquid;
v - velocity of air over the evaporation source in m / sec;
P - vapor pressure of the liquid, saturating the air at
temperature of the liquid in mm Hg. Art.; F - surface evaporation in A2.
calculated values of vapor pressure P, for some liquids evaporate at room temperature are shown in Table. 9. These tables take into account the decrease in surface temperature of the liquid through the weaning of heat by evaporation of volatile liquids.
It is interesting to note a peculiarity of the evaporation of weak hydrochloric acid. When heated, the weak solution of hydrogen chloride, it would seem more intense should be allocated specifically hydrogen chloride. But due to its hydrophilicity at a concentration below 20% evaporates predominantly water. When the concentration of hydrogen chloride above 20% of evaporation is proportional, ie, the resulting vapor contains about the same percentage of hydrogen chloride as it is contained in the solution.
The most difficult given the number of vapor and gases entering the room through leaks equipment and pipelines working under pressure. The literature on this subject can be found contradictory data.
To determine the amount of gases, erupting into the room, there is only an approximate formula NN Repin:
The safety factor, taken from 1 to 2, depending on the toxicity of gases and the state apparatus, the coefficient, which depends on gas pressure and the values of C are taken: up to 2 atm, 0,12, 2 to 7 atm - 0,18, 7 to 1917 ati-0.2, from 17 to 40 atm - 0.25, from 40 to 160 atm - 0.3, from 400 to 1000 atm - 0,35; internal volume of equipment and communications, under pressure, in m3; molecular weight of the gas or vapor; absolute temperature. Need to stipulate that the formula (22) is not exact. Use it with caution.
Give another approximate formula for counting the number of harmful substances, released by glands pump:
G = d K Vp [kg / h [, (23)
where d - diameter of shaft or stem in mm;
K - coefficient taking into account the state seals and the toxicity of emissions, taken equal to 0.0002 to 0.0003, p-pressure developed by pump.
In the production of a uniform time-space painting or varnishing the amount of emitted vapors of solvents (white spirit, xylene, acetone, etc.) is determined by the formula
G =- - [g / h], (24) 100
where F - average hourly surface of products subjected to staining or varnishing in m2 / h; A - consumption of paints in an M1 surface of the product in g/m2 and m - the content of volatile solvents in paints and varnishes in%.
Some values of A and T are shown in Table. 10.
Number of carbon monoxide released into the room when working gasoline engines, can be determined by the formula
G = 0,67 Nt [r / h], (25)
where N - nominal capacity petrol engine in liters. with; t - the time of the engine during the checkout time in minutes.
In the formula (25) ratio 0.67 was obtained on the basis of engine load, equal to 0.1, which corresponds to the movement of vehicles inside the garage, shop or warehouse. Consumption
to 1 liter of gasoline. with. taken to be 0.5 kg / h, the weight of combustion products - 16 kg per 1 kg of gasoline, and carbon monoxide - an average of 0.05 kg per 1 kg of combustion products.
By formula (25) determine the amount of released carbon monoxide while driving in the shop or warehouse forklift trucks or other vehicles.