In the study phase of tar production from natural bitumen, an attempt has been made to collect internet and library resources, and a general summary of related materials has been prepared in the form of this report. Unfortunately, the available information in this field is very limited. The only available library source is a report on coal tar from Isfahan tar refinery.
In order to carry out the laboratory phase, considering that the plan follows economic goals, samples were taken from the main depots of bituminous mines that have rich reserves and currently have extraction activities, and the required analyzes such as ash, moisture, analysis Elements and… will be done on them. Also, a fixed bed vertical furnace with a height of 50 cm and an inner diameter of 10 cm made of stainless steel 316 and equipped with a ceramic jacket for heating up to 800 degrees Celsius, a temperature controller and a condenser to collect hydrocarbon vapors (tar) has been designed.
Then different samples are carbonized in the loading furnace and under temperature control conditions and the resulting vapors are collected after passing through the condenser and will be subjected to different analyzes such as Mas-GC, humidity, etc.
It should be noted that the composition of the percentage in the tar depends on the raw material and production conditions, so the heat treatment will be the same for all samples so that a correct analysis of the results can be made, which will be discussed in detail in the laboratory phase report, and In the last stage, the final phase report and feasibility report (PFS) of the plan will be presented, in which market studies and… will be discussed.
In order to produce tar from Qairtubiei, samples were taken and analyzed from two mines that were very different in terms of geographical coordinates. The amount of fixed carbon, ash, volatile substances and moisture is determined by approximate analysis. It shows the results of elemental analysis (carbon, hydrogen, nitrogen, sulfur and oxygen) and approximate analysis (moisture, volatile substances, fixed carbon and amount of ash). . Natural bitumen is a suitable precursor for the production of carbon and tar products due to its high content of volatile substances and carbon.
Chemical and physical analysis table of two natural bitumen samples:
Type of test, test method of a sample of Qirtubiei mine, Gilangarb
An example of Qirtubiei Kohdasht mine
3 13/1 ASTM D3174-12 ash
1/32 20/4 ASTM D3172-13 carbon constant
50/73 54/1 INSO 1398-11090 Volatile substances
1/33 0/9 ASTM D3173-11 Moisture
4/2 3/96 ASTM E1915-13 Sulphur
79/4 70/21 Carbon
6/9 5/52 hydrogen
0.5 0.00 nitrogen
10/2 7/21 Oxygen
– CHNS Analyzer, CHNS-932, Leco, USA: device model for use with analysis
The geographical location of the mines used is as follows:
– Geographical coordinates of one of Qirtubiei mines located in Gilangharb, Kermanshah province:
45 44 46 45 44 46
34 12 13 34 11 40
45 44 52 45 44 52
34 11 40 34 11 9
45 44 7 45 44 7
34 11 9 34 12 13
– Geographical coordinates of one of Kohdasht mines located in Lorestan province:
47 55 32 33 23 14
A | B |
47 55 35 33 23 21
The thermal spectrum (TGA) of Qirtibi is given in a nitrogen atmosphere with a heating rate of 10°C/min. As it is known, the initial weight loss of natural tar starts from the evaporation of very volatile substances, absorbed water and volatile substances in the sample, which happens at a temperature of 18 degrees Celsius to 380 degrees Celsius. The highest weight loss is observed at temperatures between 380 and 600 degrees Celsius, which is related to the thermal decomposition of the main compounds. According to the table, the weight loss of the sample in different seasons is given. Due to the fact that more than several thousand thermal points have been recorded, therefore, up to 300 degrees Celsius, due to the fact that there is not much weight loss, weight loss numbers are given at intervals of 100 degrees, and at high temperatures, weight loss increases with every 50 degrees of temperature increase. An example is given.
As shown, the decomposition rate of the sample is relatively constant at the temperature of 580 to 800 degrees Celsius.
The weight loss curve of Qirtibii according to temperature. Weight loss of the sample at different temperatures. Weight loss (%) Initial weight (%) Temperature (C o Weight loss (%) Initial weight (%) Temperature
03/18 100 0 500 62/25 37/75
100/14 99/4864 0/5136 550/03 49/204 50/796
200/12 99/5377 0/4623 600/14 40/883 59/117
300/04 98/6133 1/3867 650 36/364 63/636
350/03 95/0693 4/9307 12/700 33/436 66/564
1/400 214/89 786/10 750/07 176/31 824/68
450/01 78/069 21/931 799/83 28/557 71/443
FT-IR analysis: 3-3
0 100 200 300 400 500 600 700 800 Archive of SID
IR-FT spectra of two natural samples used to determine surface groups in precursor material.
IR-FT spectrum of Qirtubiei mine in Gilangarb
IR-FT spectrum of Qirtubiei of Lorestan mine
Furnace design and construction with accessories:
To conduct tests and produce tar from Qirtubiei, a stainless steel furnace with a height of 50 cm and
10 cm diameter, which is equipped with a temperature controller and condensation system, is used. Condensation system to
It is designed in such a way that the vacuum pump is connected to its end so that hot vapors do not enter the vacuum pump.
One kilogram of the sample was loaded into the furnace to produce tar from Qirtubiei. Considering that the resulting vapors have a heavy molecular weight because the outlet of the furnace is open and the vapors begin to leave the furnace after formation, practically the furnace was not subjected to a high positive pressure and was almost close to the ambient pressure, which after Leaving the furnace, they were converted into liquid by passing through a condenser and collected in a container.
Also, in another experiment, the other side of the condenser was connected to a vacuum pump capable of creating a pressure of 0.7, which quickly removed the vapors from the furnace, but in the end, in terms of production efficiency, it was not much different from the first experiment, contrary to expectations. .
Performing chemical-physical analyzes on tar samples:
:(GC-Mas) mass chromatography of the test gas
The MS-GC device consists of two parts: GC (Gas Chromatography) and MS (Mass Spectrometry).
In this device, GC and Mass are not separated from each other, and entering the sample into the Mass device is through GC, so in this device, we can only prepare a mass spectrum from samples that we can inject into the GC, so mainly This device is used to identify and determine the amount of fractions of substances that are volatile (such as plant essential oils that have a low boiling point) or become volatile due to combination with some reagents or special solvents.
In the MS-GC device, the components of a mixture are separated in order by a chromatography column, and after removing the resulting gas, they enter the ion source of the mass spectrometer, and then, due to the production of high-power electric fields, quantitative and qualitative identification of the components is carried out. The mixture is based on the ratio of electric charge to their mass. This device is one of the most advanced devices used in device analysis by gas chromatography method and the compounds are identified after separation using a mass spectrometer.
Mass-GC devices are widely used in the pharmaceutical, agricultural, petrochemical, etc. industries in order to isolate and identify unknown compounds with low boiling points.
The tar obtained from natural bitumen has bituminous substances and molecules with high boiling point, so after study and investigation
From different research centers in the country, this result was obtained that first before injecting into the device, using distillation
Bituminous components with a boiling point above 400 degrees Celsius were separated from the raw sample one by one. The different fractions obtained from the distillation are shown one by one. As shown in the figure, fraction number 1 corresponds to the first sample taken out of the distillation column and sample 9 is the last part.
Sample 1 is an aromatic material with a low boiling point, so that it evaporates completely after a while at the temperature of the laboratory. Sample number 2 is mainly aromatic and heterocyclic. Sample 4 to 6 is a mixture of three components, but the aliphatic percentage is higher.
Samples 8 and 9 are mainly aliphatic, which can probably be used for oil production. 250 ml of crude tar was poured into a half-liter balloon and the device set was placed in an oil bath and a thermometer was placed inside the hot oil to measure the temperature.
At the end of the work, a torch was used to remove the last drops of oil from the bituminous phase (distillation residue). The sample was slowly heated and the fractions were collected as the temperature increased. It is worth noting that the fraction of sample 5 was analyzed by Mas-GC due to its high volume compared to other fractions and, contrary to expectations, about 100 types of compounds were identified in this fraction. Considering that the results of QI and TI and density analysis for the tar samples obtained under negative pressure and positive pressure for two mines did not show any particular change, as a result of the Mas-GC test, it was positive only for samples with size compression.
According to the data in fraction one compounds of decane, decane, cyclopentane derivative, cyclooctane derivative, 1-dodecane, dodecane, 1-tridecane, nonane, tetraoctane derivative, 1-decanol, 2-hexyl from 2 to 8 percent (42.6% in total) of its volume, which are mainly aliphatic compounds.
In the fraction of two toluene compounds, heptane derivative, benzene derivatives, cyclopropane derivatives, nonane, decane, 1 decane, and
Decane, 1-methyl-1H-2 and 3=benzodiazepines made up from 2 to 9% (34.7% in total) of the volume.
In the fraction of three compounds, toluene, octane, orthoxylene, paraxylene, benzene derivatives, decane, andecane, dodecane, tridecane, benzocycloheptatriene, tetradecane, benzothiophene, ethylpentamylbenzene make up from two to 8% (67% in total) by volume. Of which 41% are aromatic substances and the remaining 26% are aliphatic substances.
Along with the advancement of computer capabilities, there have been major advances in modeling and simulation of separation processes
Multi-stages have been done and mathematical models have become more flexible and realistic. Still, experimental and complex thermodynamic equations are used more. The emergence of old algorithms are also being corrected.
It should be pointed out that for an engineer, the problem of choosing the best method “relatively” for the applications he is considering is to act according to the existence of different algorithms.
A) Method based on set of equations
b) Relaxation method category
c) Methods based on simultaneous solution of equations
(The basic problem related to simultaneous solution methods is the need for a good initial approximation for the problems and also the need for
The memory is high and the execution time is high.)
– From the point of view of engineering, there are four main parts in the simulation of multi-stage separation processes
1- accurate prediction of thermodynamic properties such as equilibrium ratio K
2 – Presentation of the general mathematical model expressing the system
3- Creating a valid and effective solution method
4- Direct application of these methods in design issues
The presented mathematical model should be as general as possible, so that one model can be used for several processes
used All these models start with basic mass and heat balance equations and equilibrium relationships. These equations should be able to include the efficiency of steps, chemical reaction, side refluxes, etc. In addition, system limitations or specified process conditions should also be considered in these models.
Although creating a comprehensive model is not a difficult task, it is difficult to obtain a solution method that can effectively solve these comprehensive models. For this reason, all simulation models are usually accompanied by a series of simplifying assumptions.
Complex simulations of multi-stage separation processes include solving a set of nonlinear algebraic equations (it should be noted that if dynamic simulation is intended, some of these equations will be nonlinear differentials) that solve such systems It involves repeating methods. Although these problems all have the same structure of equations, the convergence characteristics of the solution are different from one type of problem to another and also from one type of algorithm to another type. The spectrum related to distillation simulation of a sample of natural bitumen tar is given, which shows the amount of substances that are distilled at different temperatures from the temperature range of 81 to 590 degrees Celsius.
Distillation simulator diagram of a sample of Qirtubiyi tar
Distillation simulator curve of a natural bitumen tar sample
Physical characteristics tests:
In order to produce different products from tar, some parameters are very important. For example, the degree of solubility in
Quinoline (QI) is very important for the production of naphthalene from tar, or the degree of solubility in toluene (TI) or the degree
Ash or moisture should be clear. The parameters that are important in the tar business and in a way express the quality
Tar and finally its price are given in table (3-4).
Table 4-3 – Chemical-physical characteristics of two tar samples
Unit Method Test
Sample 1 Sample 2
QI % STPTC PT 11
TI % STPTC PT 7
ASTM D Ash % 2415
0,0 0,0 % ASTM D95 W.C
ASTM D Flash point 33 32 oC 93
ASTM D Dencity 1298-12b
0,93 0,91 g/cm
Discussion and conclusion of tar production from natural bitumen:
: FT-IR test
Infrared spectroscopy is based on the absorption of radiation and investigation of vibrational mutations of molecules and polyatomic ions. This method is used as a powerful and developed method to determine the structure and measurement of chemical species.
Also, this method is mainly used to identify organic compounds, because the spectra of these compounds are usually complex and have a large number of maximum and minimum peaks that can be used for comparative purposes. To qualitatively identify an unknown sample, the type of functional groups and bonds in its molecules, draw the infrared spectrum of the sample and by referring to the relevant tables that show the vibration position of different bonds or the IR spectrum of objects, the wavelength or wave number of the groups and identify links.
In the normal IR spectrophotometry, the electromagnetic spectrum extends from the visible to the infrared region.
Then a small part of it reaches the detector according to the frequency or wavelength and is recorded. In this case, the obtained spectrum will be recorded in the range of frequency or wavelength. The characteristic of IR-FT is that all the wavelengths of the desired spectral region are irradiated to the sample at the same time. While in sputtering methods, only a small part of the wavelengths reach the sample at a time.
Therefore, the speed, resolution, and signal-to-noise ratio in the Fourier transform method have a significant advantage over the normal IR method. Some of the information that can be obtained from infrared Fourier transform spectroscopy (IR-FT) includes the following: qualitative and quantitative identification of organic compounds, determining the type of functional group and bonds in their molecules. In order to identify the functional groups, infrared spectra were taken from the two mines of Gilangarb and Lorestan, as well as the tar obtained from them, and the spectra are shown in the figure below.
Spectra related to natural bitumen and Gilangarb tar and spectra related to Qirtubiei and Lorestan tar.
In general, there is an obvious difference between the spectrum obtained from Qirtubiei Gilangarb and the mine obtained from Lorestan.
And this proves that the geographical area, climate and lifespan affect the quality of these mines.
and these changes can be seen in the tar obtained from them.
(GC-Mas) mass spectrometer test:
By using partial distillation of tar oils under different cuts from crude tar samples, separation
became Both samples have many components, but for the Lorestan sample, there are mainly aromatic compounds such as xylene, toluene and benzene derivatives, cycloalkane compounds and paraffin derivatives such as decane, thatdecane, nonane and octane. For example, decane and its derivatives, derivatives of cycloalkanes, oxalic acid and benzene derivatives are observed in Gilangreb mine.
(Simulation Distillation) Distillation similar to the test:
The percentage of distillation is observed at different temperatures, and the distillation rate is in the temperature range of 81 to 590 degrees Celsius.
Distillation percentage at different temperatures for a crude tar sample, recovery percentage (IBP) temperature C o recovery percentage (IBP) temperature (C
81 0/5 398 60
163 5 415 65
201 10 431 70
222 15 448 75
246 20 465 80
270 25 484 85
291 30 507 90
313 35 537 95
331 40 590 99/5
Test of chemical-physical properties of bitumen:
It was determined by performing analyzes such as the solubility in quinoline (QI) and the solubility in toluene (TI)
In this case, both samples are not much different, but there is a big difference with tar obtained from coal. According to the expert report of Isfahan Tar Refinery, the tar obtained from natural bitumen, according to the results of density, QI and TI tests and comparing it with the sample obtained from coal tar, Qirtubiei tar is more similar to a tar oil.
QI and density are about 7 and 1.06 for coal tar and zero and 0.9 for natural tar, respectively. Also, the flash point for the production of natural bitumen tar is about 32 and for coal tar is usually above 60 degrees Celsius, and this shows that there are more volatile substances in natural bitumen tar, and due to the nature of natural bitumen, which is of petroleum origin, compared to Coal is a natural problem.