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CHEMICAL SCIENCES
MATHEMATICAL MODELLING OF PROCESSES OF ADSORPTION Babayev R.K. (Republic of Azerbaijan) Email: [email protected]
Babayev Rauf Kamil oglu - PhD in Тechnics, Associate Professor, DEPARTMENT OF PETROCHEMICAL TECHNOLOGY AND INDUSTRIAL ECOLOGY, AZERBAIJAN STATE OIL AND INDUSTRIAL UNIVERSITY, BAKU, REPUBLIC OF AZERBAIJAN
Abstract: kinetic regularity process researches of adsorptive dearomatizing paraffins fracture at 200-320° (temperature) in aluminosilicate adsorbent in a fixed layer have been carried out. The main kinetic regularities of adsorptive paraffins dearomatization running in nonstationary conditions, symbolized by adsorbent adsorptive volume have been proved . Mathematical model of liquid-phase adsorption in the fixed layer of adsorbent has been developed. Equations of diffusive dynamics of non-equilibrium izothermal adsorption have been solved. Diffusion parameters of liquid-phase adsorption have been defined. Effective algorithm for diffusive parameters definition has been developed, influence regularities of initial adsorptive concentration, raw materials velocity and adsorbent graining in the fixed layer on the liquid paraffins adsorptive dearomatizing process base have been studied. Keywords: component, modelling, adsorptive, adsorber.
МАТЕМАТИЧЕСКОЕ МОДЕЛИРОВАНИЕ ПРОЦЕССА
АДСОРБЦИИ Бабаев Р.К. (Азербайджанская Республика)
Бабаев Рауф Камил оглы - кандидат технических наук, доцент, кафедра нефтехимической технологии и химической технологии, Азербайджанский государственный университет нефти и промышленности, г. Баку, Азербайджанская Республика
Аннотация: проведены исследования кинетических закономерностей процесса адсорбционной деароматизации парафинов фракции 200-320° на алюмосиликатном адсорбенте в стационарном слое. Установлены основные кинетические закономерности процесса адсорбционной деароматизации парафинов, протекающие в условиях нестационарности, обусловленной адсорбционной ёмкостью адсорбента. Разработана математическая модель жидкофазной адсорбции в неподвижном слое адсорбента. Решены уравнения диффузионной динамики неравновесной изотермической адсорбции. Определены диффузионные параметры жидкофазной адсорбции. Разработан эффективный алгоритм определения диффузионных параметров. Определены закономерности влияния начальной концентрации адсорбтива, скорости сырья и зернения адсорбента в неподвижном слое на примере процесса адсорбционной деароматизации жидких парафинов. Ключевые слова: компонент, моделирование, адсорбтив, адсорбер.
As is known liquid paraffines are widely used as many petrochemical processes initial products: chlorination, dehydrogeneration, oxidation, cracking-with subsequent alkylbenzolsulphonates, alcohols and other products obtaining.
Aromatic hydrocarbons and other impurities contained in liquid paraffines affect negatively on petrochemical reactions and on microbiological synthesis. In this case liquid paraffin users put in strict claims in residual content of aromatic hydrocarbons - not more
than 0.01 mass %. In present adsorptive paraffins dearomatizing process realized in the fixed layer of synthetic aluminosilicate adsorbent suits the menthioned requirements.
In this connection main kinetic regularity research of adsorptive dearomatizing of paraffin fractures 200-320oC in comparison with carbamid dewaxing process on synthetic aluminosilicate adsorbents presents an important theoretical and practical interest [1-2].
Kinetic regularity researches processes of adsorptive paraffins fracture 200-320° dearomatizing on aluminosilikate adsorbent in a fixed layer have been carried out, adsorptive paraffins dearomatizing process main kinetic regularities running in nonstationarity conditions symboled with adsorptive volume adsorbent have been established. Liquid-phase adsorption mathematical model in adsorbent fixed layer has been developed. Diffusive-dynamics equations of non-equilibrium isothermal adsorption have been solved. Liquid-phase adsorption diffusive parameters have been determined. Diffusive parameters effective algorithm defenition has been developed. Initial adsorbent concentration influence , raw speed and adsorbent graining regularities in fixed layer on the liquid paraffins adsorptive dearomatizing process base have been defined.
At the present time intensification and sorptive processes economical effectiveness increase and modern claims to ecologically pure production as well represents these processes mathematical model development importance. So, for example, during practical calculation carrying out diffusion parameters value exact estimation plays an important role in sorptive processes optimization and designing very much.
Adsorptive dearomatizing process of paraffins in the adsorbent fixed layer runs in its desactivation conditions, symbolized by aromatic hydrocarbons sedimentation in adsorbent pores in due course.
In this connection the main kinetic regularities process research of adsorptive dearomatizing paraffins fraction at 200-320°C in comparison with carbamid dewaxing process on synthetic alyminosilicate adsorbents represents an important theoretical and practical interest.
At the present time intensification and increase of sorptive processes, economical effectiveness as well as modern requirements for ecologically pure production represent the development and importance of mathematical model for these processes. So, for example, while practical calculations being carried out, exact estimation of diffusive parameters plays an important role in optimizing and designing of sorptive processes [3-4].
The idea of taking into account the effect of the internal and external factors on the process so as their sum total which permits the study of process mechanizm by less complicated methods and to compare values of intercommunicated internal and external factors easily was put into the base of mathematical model development of adsorptive dearomatizing of liquid by aluminosilicate adsorbent. Mathematical model of the process includes the following equations:
balance of adsorbent substance in the system
SC SC da ^ d2 C
— + o — + m — = D3- (1)
St dx St dx2 diffusion of adsorbate in micropores of adsorbent
da, ^ ,d2a, 2 da„^ da^ = Da (—- ^ (2) St dr„ r, dr,
diffusion of adsorptive substances in transport pores
SC n,d2Cc 2 SC
— = Dc (-^ +---) (3)
St dr r dr
adsorption kinetics in the form of diffusion velocity in the microporous formations.
5a fda*-,
— = 4Daxr02 N ) r*=ro (4)
От or 0
equilibrium in the form of Langmuire equation
a» bCc
ap =7^^ (5)
1 + bC
Where и - is solution linear flow rate D3 - is effective diffusion coefficient m=(l-m')/m', m-is adsorbent layer porosity
C is adsorptive concentration; a is adsorbate concentration; а* is adsorptive substance concentration in microporous formations; Da is diffusion coefficient of adsorptive substance in microporous formations; x is adsorbent layer Reight coordinate; т is adsorption time (duration); ro is microporous formations current radius; Cc is adsorptive concentration in transport pores; ro is microporous formations radius; Dc is adsorptive substance diffusion coefficient in transport pores; R is adsorbent grain radius; r is current radius of adsorbent grain; N' is the number of microporous formations in unit volume; ap is equilibrium concentration of adsorbate; b is constant of Langmuire equation.
Solution of equiation (1) - (5) system has been carried out by the help of Laplace-Carson conversion. Conclusions
1. While kinetic regularities process research of paraffins fraction 200-320° of adsorptive dearomatizing on alumosilicate adsorbent in stationary layer being carried out it has been proven that flow rate and process temperature don't essentially affect on its kinetics. Maximum adsorption dimention is obtained at the conditions of adsorptive equilibrium.
2. Mathematical model of liquid-phase adsorption in the fixed layer of adsorbent at the liquid paraffins adsorptive dearomatizing process example has been worked out.
3. Diffusion parameters of liquid phase adsorption have been defined. It is shown that effective coefficient of diffusion changes considerably at the height of layer (especially for adsorbers with adsorbent layer of large sizes). That's why it is necessary to take into consideration the effective coefficient of diffusion while modelling, optimization and optimum projecting of industrial adsorbers.
4. Optimum technological and constructive parameters of paraffins adsorbtive dearomatizing process have been defined.
References in English / Список литературы на английском языке
1. Berlin M.A., Gorechnikov V.G., Volkov I.G. Oil and natural gas refinery. Chemistry. Moscow, 1984.
2. Campbell D.M. Natural gas cleaning and refiner. Nedra. Moscow, 1977.
3. Kuznetsov A.A., Sudacov B.N. Main processes and hydrocarbons gases refinery apparatus calculations. Chemistry. Moscow, 1983.
4. Varfolomeeva V.V., Konygin S.B., Sanoyan A.G. Modelling of monomolecular adsorption kinetics using the method of probabilistic cellular automation // 8th International conference on fundamentals of adsorption. May, 2004. USA. Рp. 87.
References / Список литературы
1. Берлин М.А., Горечников В.Г., Волков И.Г. Переработка нефти и природного газа. Химия. Москва, 1984
2. Кампбел Д.М. Очистка и переработка природного газа. Недра. Москва, 1977.
3. Кузнецов А.А., Судаков Б.Н. Расчеты основных процессов и углеводородных газов. Химия, Москва, 1983.
4. Варфоломеева В.В., Коныгин С.Б., Саноян А.Г. Моделирование кинетики мономолекулярной адсорбции методом вероятностной клеточной автоматизации // 8-я Международная конференция по основам адсорбции. Май, 2004. США. С. 87.
ALKYLATION OF AROMATIC HYDROCARBONS C7-C8 WITH ONE-ATOMIC SATURATED Q-C4 ALCOHOLS ON ZEOLITES Gahramanov T.O. (Republic of Azerbaijan) Email: [email protected]
Gahramanov Taleh Ordukhan - PhD in Chemistry, Associate Professor, PHYSICAL AND COLLOID CHEMISTRY DEPARTMENT, CHEMISTRY FACULTY, BAKU STATE UNIVERSITY, BAKU, REPUBLIC OF AZERBAIJAN
Abstract: the reaction is carried out by alkylation of toluol, ethylbenzene, o and m-xylene with single-stranded alcohols C1-C4 at zeolites. Particular attention is paid to the reaction of alkylation of C7-C8 aromatic hydrocarbons on the faujasite structure zeolites (type X and Y), morendine and high-zeolite zeolites of the ZSM-5 pentasil analogs It has been revealed that the structure of crystalline aluminosilicate, including the dimensions and geometry of the cavities, the concentration and strength of acid sites, largely determine the direction of transformations of the initial substances and the type of products of the main and side reactions that occur in the system. It is shown that, by chemical modification, it is possible to change the catalytic and molecular sieve properties of zeolites. Paraselectivity of catalysts is regulated by varying the pore volume and the concentration of strong acid sites. It was found that the catalytic properties of zeolite systems depend not only on the presence ofproton and aprotic centers, but also on their micropore size and availability for reacting molecules.
Keywords: zeolite, alkylation, methanol, ethanol, isopropanol, tert-butanol, toluene, ethylbenzene, xylenes, pentasyle, ultrasyle, ,methyl- ethylbenzenes, diethylbenzenes, ethyltoluenes, dimethyl tert-butylbenzenes, cymenes.
АЛКИЛИРОВАНИЕ АРОМАТИЧЕСКИХ УГЛЕВОДОРОДОВ С7-С8 ОДНОАТОМНЫМИ НАСЫЩЕННЫМИ СПИРТАМИ С1-С4
НА ЦЕОЛИТАХ Гахраманов Т.О. (Азербайджанская Республика)
Гахраманов Талех Ордухан - кандидат химических наук, доцент, кафедра физической и коллоидной химии, химический факультет, Бакинский государственный университет, г. Баку, Азербайджанская Республика
Аннотация: рассмотрены реакции алкилирования толуола, этилбензола, о- и м-ксилола одноатомными насышеынными спиртами С1-С4 на цеолитах. Особое внимание уделено реакции алкилирования ароматических углеводородов С7-С8 на цеолитах фожазитовой структуры (типа Х и У), морденита и высококремнеземных цеолитах типа пентасилов аналогов ZSM-5. Выявлено, что структура кристаллического алюмосиликата, включая размеры и геометрию полостей, концентрация и сила кислотных центров определяют во многом направление превращений исходных веществ и тип образующихся продуктов основной и побочных реакций, протекающих в системе. Показано что, путем химическое модифицирование возможно изменение каталитических и молекулярно-ситовых свойств цеолитов. Параселективность катализаторов регулируется изменением
