Calculation modulus for water and methanol segregation processes from gas condensate has been developed. Applying the developed technological system the influence of process variables on segregation processes of water and methanol is studied. Modes of operation of liquid separators at which the most efficient segregation of water-methanol solution from unstable condensate occurs are recommende

Kravtsov, Anatoly Vasilyevich

Kuzmenko, E. A.

Moyzes, O. E.

Usheva, N. V.

Electronic archive of Tomsk Polytechnic University

While modeling the influence of the main perturbation actions (fluoride concentration and gas consumption) and possible control actions (raw material loading, heat removal intensity and heating) on stationaryand transient conditions in the device was estimated.The developed mathematical model implemented inthe package MATLAB 7.0 will be used for synthesizing modernized control algorithm of DCR. Improvement of algorithm is in automated stabilization of the required temperature distribution profile in the device retort by changing rawmaterial loading in the device. Control algorithm will beimplemented at modern software with software support athighlevel objectoriented programming language. Themodel may be also used for studying other control objects inradiochemical technology of counterflow and uniflow devices with gas and disperse fluxes (for example, flame reactorsfor obtaining UHF, counterflow devices for processing product unreacted in fluoridation reactor etc.).Bulletin of the Томsк Pоlytеchnic University. 2007. V. 311. № 356REFERENCES1. Turaev N.S., Zherin I.I. Chemistry and technology of uranium. –Moscow: Publishing house «Ruda i Metaly», 2006. – 396 p.2. Andreev G.G., Permyakov O.E. Chemical kinetics of heterogeneousnoncatalytic process in nuclear fuel technology. – Tomsk: TPUPress, 2000. – 83 p.3. Kasatkin A.G. Main processes and devices of chemical technology.– 10th iss., reprint, updated. – Moscow: «Alyans», 2004. – 753 p.4. Kafarov V.V., Glebov M.B. Mathematical modeling of the main processes in chemical productions. – Moscow: Vysshaya Shkola, 1991.– 400 p.5. Methods of modeling catalytic processes at analogue and digital computers / Ed by. А. Ermakova. – Novosibirsk: Nauka, 1972. – 150 p.6. Aerov M.E., Todes O.M. Hydraulic and thermal basis of operation ofthe devices with stationary and boiling granular layer. – Leningrad:Khimiya, 1968. – 510 p.7. Verzhbitsky V.M. Numerical techniques. – Moscow: VysshayaShkola, 2001. – 382 p.Received on 07.12.2006When producing and preparing gas condensate for transportation the supply of raised concentration methanol to the system is provided. When mixing hydrocarbon condensatewith water methanol solution the mixture which should bedivided is formed. Indistinctness of division of watermethanol and hydrocarbon phases results in considerable losses ofmethanol with unstable condensate and tank gas.Applying methods of mathematical modeling andusing computer analogues (A) allows solving these problems and many other ones rather efficiently.On the basis of experience in developing analoguesfor various technologies we developed the mathematicalmodels [1–4] of the processes of commercial treating ofoil, gas and gas condensate on the basis of which thetechnological analogue (TA) for computing materialbalances and online analysis of operating practices ofcomplex gas treatment device (CGTD) was developed.The main blocks of the developed TA of complex gasand gas condensate treatment technology are modulusof computing processes of separation, tip leakage, liquidseparation, throttling and heat exchange.Constants of phase equilibrium were calculated bythe technique proposed in papers [5, 6] on the basis ofwhich there is the main GofmanKramp equation. Forcalculating constants of phase equilibrium of methanoland water the equation of TeckStill was chosen [7].The given correlation differs in high accuracy at calculating vapor pressures of polar substances and substances with hydrogen bonds at low temperatures. The equation of TeckStill for calculating saturated vapor pressure of chemical substances has the following form [7]:(1)25,2691 2,0753 3,173811,14893 0,11719ln0,03174 0,375 ln(1,042 0,46284 )15,2691 2,0753 3,1738,10,040 1rrrVPr rñA hrrTTP AT TATA hTα+ ⋅ − ⋅⎛ ⎞− − ⋅ −⎜ ⎟= +⎜ ⎟⎜ ⎟− ⋅ − ⋅⎝ ⎠+ − ×⎡ ⎤− +⎢ ⎥+ ⋅ − ⋅⎢ ⎥×⎢ ⎥⎛ ⎞+ ⋅ −⎢ ⎥⎜ ⎟⎢ ⎥⎝ ⎠⎣ ⎦UDC 665.12.001.57MATHEMATICAL SIMULATION OF WATER AND METHANOL SEGREGATION PROCESSES AT FIELD PREPARATION OF GAS CONDENSATEA.V. Kravtsov, N.V. Usheva, O.E.Moyzes, E.A. KuzmenkoTomsk Polytechnic UniversityEmail: moe@tpu.ruCalculation modulus for water and methanol segregation processes from gas condensate has been developed. Applying the developedtechnological system the influence of process variables on segregation processes of water and methanol is studied. Modes of operation ofliquid separators at which the most efficient segregation of watermethanol solution from unstable condensate occurs are recommended.whereare the reduced temperatures; Тс, Тb are the critical andnormal boiling temperatures of the component; Рс is thecritical pressure; αс is searched by the formula (1) fromthe condition: PVPr=1/Рс and Tr= Tbr.Comparison of values of saturated vapor pressures ofmethanol and water calculated by the technique givenabove and scientific literature data showed their satisfactory convergence [8, 9].Efficiency of methanolic water segregation in liquidseparators depends to a considerable extent on drop size formed at material flow movement through the supply pipeline. Therefore, the stage of dispersed phase tipleakage should precede the process of methanolic waterprecipitation in the device. Tip leakage occurs in theflow at mixture movement through the supply pipeline,in branch pipes of liquid separators and capacities. Thesize of formed drops is taken into account at calculatingsedimentation process [1, 2] therefore it is important toestimate the influence of technological conditions forgas condensate preparation for the process of tip leakage and further segregation of methanolic water.Calculation of tip leakage and sedimentation processes was fulfilled similarly to the techniques given inthe paper [4] size of drop diameter was calculated by theformula suggested in [10].Modeling processes of commercial preparation ofoil, gas and gas condensates the calculation of water andwatermenthol solution sedimentation process is ofconsiderable difficulty. In the TA applied at the presentthe phase equilibriums are mainly calculated in the system: hydrocarbonsmethanolwater. According to thephysical entity two processes are considered in liquid separators: gas separation from liquid phase and separation of watermethanol solution from condensate owingto sedimentation processes.Thus, mathematical model of liquid separator includes the model of separation process and the model ofsedimentation process.The technological analogue developed by us in thefoundation of which there are mathematical models ofthe main processes of gas condensate preparation allowscomputing device material balances, compositions ofproduct flows subject to the consumption, water content in supply steam, methanol supply and a number ofconstructive peculiarities of the devices such as devicevolume, sedimentation zone volume, height of watermethanol layer and diameter of inlet branch.In general, TA allows predicting the influence ofthermobaric conditions, composition of stratal mixture,consumptions and constructive peculiarities of the devices applied in the given technological diagram for theprocesses of commercial preparation of gas condensateincluding separation processes of watermethanol solutions.For increasing efficiency of CGTD operation andquality of the obtained commercial output the optimaltechnological conditions supporting the best water andmethanol segregation from the unstable condensateshould be selected. Using TA the influence technological parameters on processes of commercial preparationof gas condensate was investigated.Liquid separators and capacitors of differenttechnological purposes are provided in technologicaldiagram (Fig. 1) of the device for complex preparationof gas condensate [3] for water and methanol separation(Table. 1).Fig. 1. Principle flow diagram of gas and gas condensate preparation: С1, С2, С3 are the separators; БЭ is the ejector block;Т is the heat exchanger; Р1, Р2 are the threephase separators; Д is the degasifier; БЕ is the block of raw material capacities; К1, К2 are the rectifying columns; П1,2 are the furnaces; Е1 is the capacity of condensed gas gathering; Е2 isthe irrigation capacity; ПБФ is the propanebutane fraction; МЭФ is the methaneethane fractionTable 1. Technological conditions of operation of liquid andcapacity separatorsThe influence of technological parameters: pressure, temperature and mixture consumption on waterdrop formation (watermethanol solution) in carboncondensate was studied by the model of tip leakage process (Fig. 2).Fig. 2. Dependence of drop diameter of methanolic water onstream consumption0501001502002503003500 10 20 30 40Consumptions, kg/hDrop diameter, mkmParametersDevicesSeparator Р1 Separator Р2 Capacities БЕTime of mixture being inthe device, h0,7 0,5 1,1Diameter of device inletfitting, m0,15 0,08 0,15Temperature, °С 19,0 3,0 22,5Pressure, МPa 3,8 3,2 2,4Input treamDry gasUnstable condensateStable condensate0,375ln, , ,(1 ) 1b c bbr r brc br br c ñH P TTA h T T TRT T T T TυΔ= = = =⋅ − −Сhemistry57The investigations showed that such parameters astemperature and pressure influence weakly the drop diameter value.And at the same time, as calculations showed, diameters of supply pipelines and branch pipes in liquidseparators as well as mixture consumption influencegreatly the size of forming drop. The influence of material flow consumptions on liquid drop size was studied(Fig. 2). It follows from calculations that, for example,changing consumptions in the range of 7,4...37,4 t/h(Р1) drop diameter decreased from 68 to 36 mkm and inР2 changing consumption from 2,7 to 32,7 t/h drop diameter decreased from 126 to15 mkm.Applying technological analog the processes of gascondensate commercial preparation at various technological conditions of CGTD operation were studied.As the results of calculations showed 0,023 wt. % ofmethanolic water enters commercial gas and 0,15 wt. %is removed with unstable condensate.The results of studying the influence of technologicalparameters on water and methanol segregation processesat CGTD are given in Table 2. The analysis of the obtained results showed that temperature increase in P2 at simultaneous pressure decrease promotes reduction ofmethanolic water content in unstable condensate. Temperature decrease in the first separator also promotes reduction of water and methanol content in condensate.The results of calculation of water and methanol segregation processes in capacities at CGTD and studyingthe influence of technological parameters on the indicesof the process are given in Table 3.Pressure variation in the range from 1,5 to 3,5 MParesults in insignificant changes in quantity of segregatedwater phase (Table 3). Temperature at its change from 3to 30 °С influences similarly. Residual condensate watering changes from 0,009 to 0,011 wt. %.Table 3. Research of technological parameters influence on water and methanol segregation processes in capacitiesProcesses of segregating water and methanol smallquantities causes rather complicated. As the researchesshowed the time of mixture being in the device has the maininfluence. Increasing this time twice (that is switching onthe second capacity, variant 4, Table 3) results in decreasingresidual water and methanol content approximately two times as well. That is, a good segregation of watermethanolsolution from unstable condensate is observed in the studied range of temperature and pressure variation. Therefore,at efficient operation of the capacity (БЕ) the condensatecontaining approximately 0,01 wt.% of water and methanolmay enter the CCW that should not influence greatly thetechnological conditions of the device operation.Thus, modeling the processes of gas condensatecommercial preparation applying TA allows estimatingoptimal technological modes of the device operationand determining water and methanol quantity in allflows of commercial device.ParametersCalculation variants1 2 3 4 (2 БЕ) Т=10 °СР=2,4 МPаТ=22,5 °СР=2,4 МPаТ=30 °СР=2,4 МPаТ=22,5 °СР=2,4 МPаInput content, kg/hWater 25,1Methanol 15,0Watering, wt. % 0,15Output content, kg/hWater 1,7 1,5 1,4 0,7Methanol 1,0 0,9 0,9 0,4Watering, wt. % 0,011 0,009 0,009 0,0043Bulletin of the Томsк Pоlytеchnic University. 2007. V. 311. № 358Table 2. Studying technological parameters influence on water and menthol segregation processes in liquid separators Р1 and Р2ParametersCalculation variant1 2 3 4 5 6Р1 Р2 Р1 Р2 Р1 Р2 Р1 Р2 Р1 Р2 Р1 Р2Temperature, °С 18,9 3,0 10,0 3,0 18,9 15,0 10,0 15,0 18,9 3,0 18,9 15,0Pressure, МPa 3,8 3,2 3,8 3,2 3,8 2,6 3,5 2,6 3,8 3,2 3,8 2,6Methanolic water content in liquid phase at separator input, wt.% 2,54 1,61 2,54 3,18 2,54 3,08 2,54 3,19 2,47 3,11 2,46 3,10Methanol and water content in unstable condensate from liquid separators, kg/hWater 16,4 8,7 17,2 8,1 16,4 6,6 17,5 6,6 17,6 5,7 17,7 4,3Methanol 0,0 15,0 0,0 14,5 0,0 11,3 0,0 11,2 0,0 13,3 0,0 10,0Σ 16,4 23,7 17,2 22,6 16,4 17,9 17,5 17,8 17,6 19,0 17,7 14,3Methanolic water content, wt. % 0,11 0,20 0,11 0,19 0,11 0,16 0,12 0,16 0,11 0,17 0,11 0,14Methanol and water content in unstable condensate, kg/hWater 25,1 25,5 23,7 23,0 24,0 23,4Methanol 15,0 14,5 12,6 11,3 11,2 13,3Σ 40,1 40,0 36,3 34,3 35,2 36,7Methanolic water content, wt. % 0,15 0,14 0,14 0,13 0,13 0,14Methanol and water content in commercial gas, kg/hWater 0,4 0,4 0,4 0,5 0,5 0,4Methanol 17,6 17,6 17,5 17,5 17,6 18,8Σ 18,0 18,0 17,9 18,0 18,1 19,2REFERENCES1. Kravtsov A.V., Usheva N.V., Moyzes O.E., Reizling V.I., KuzmenkoE.A. Information analogue for technology of primary oil preparation// Khimicheskaya Promyshlennost. – 1999. – № 7. – P. 50–54.2. Ivanov V.G., Maslov A.S., Kravtsov A.V., Usheva N.V., GavrikovA.A. Increasing efficiency of the technology of gas condensate commercial preparation // Gazovaya Promyshlennost. – 2003. – № 7. –P. 54–57.3. Kravtsov A.V., Usheva N.V., Knyazev A.C., Shkrobotko O.V. Modeling heat exchange processes at commercial preparation of gas andgas condensate at SeveroVasyugansk deposition // Bulletin of theTomsk Polytechnic University. – 2005. – V. 308. – № 5. –P. 101–104.4. Usheva N.V., Kravtsov A.V., Moyzes O.E., Kuzmenko E.A. Modeling technologies of oil commercial preparation // Bulletin of theTomsk Polytechnic University. – 2005. – V.308. – № 4. –P. 127–131.5. Shilov V.I., Klochkov A.A., Yaryshev G.M. Calculation of phaseequilibrium constants of natural oilgas mixture components // Neftyanoe Khozyaistvo. – 1987. – № 1. – P. 50–55.6. Shilov V.I., Krikunov V.V. Forecasting phase state of natural oilgassystems // Neftyanoe Khozyaistvo. – 2002. – № 8. – P. 102–103.7. Rid R.S., Prausnits D.M., Shervud T.K. Gas and liquid properties, –Leningrad: Khimiya, 1982, – 592 p.8. Makogon Yu.F. Gas hydrates, prevention of their formation and use.– Moscow: Nedra, 1985. – 232 p.9. Gurevich G.R., Brusilovsky A.I. Handbook in calculation of gas state and properties of gas condensate mixtures. – Moscow: Nedra,1984. – 264 p.10. Guseinov Ch.S., Asaturyan A.Sh. Defining drop modal size in twophase flow // Prikladnaya Khimiya. – 1977. – № 4. – P. 848–853.Received on 07.12.2006Сhemistry59Methanol use in gas dewatering system and as aninhibitor of hydrator formation is the main technological approach of its applying in gas and oil branches.Methanol content in industrial solutions formed afterits application varied at the average in the range of30...50 wt. %. Absence of regeneration methods of suchsolutions in some cases and further deep purification ofprocess waste waters from methanol is rather expensiveboth in terms of money and in the fact of deteriorationof ecological situation around this deposition. Methanol delivery to the Extreme North fields at least redoubles its cost. Methodical discharge or burning industrialwastes containing methanol into environment maycause serious stress for ecosystem of the given region.Therefore, technologies intended both for methanol regeneration and further purification stage from it attractattention.In this connection works aimed at the developmentof methanol extraction technology from wastes of gascondensate fields and return of methanol main part into technological cycle with further reducing methanolresidual concentration in discharged industrial wastes tomaximum permissible concentration (3 mg/dm3) arerather actual.Methanol may be regenerated by rectification as themost reliable and efficient technology allowing extracting from industrial wastes up to 99 wt. % of methanolwith residual concentration in vat waters about 1 wt. %and more [1–4]. The most perspective destructivemethod of industrial waste purification among the existing ones is the method of deep catalytic oxidation[5, 6]. However, the method is expensive due to applying catalysts of noble metals and their rapid poisoning.Therefore, in contrast to the less efficient technologiesexisting at the present time [710] the technology providing rectification with further methanol oxidation in vatresidual in the device with boiling catalyst layer is proposed. Using pseudoliquated layer the methanol oxidation process should be more efficient [11] as the pseudoliquated catalyst layer is capable of continuous functioning with mixtures where impurity concentration islow.Taking into account low methanol concentration(15 wt. % and lower) and high water content after rectification stage in vat residual it was necessary to state thepossibility in principle of deep catalytic methanol oxidation up to carbon dioxide and water and select the catalyst being capable of operating in these conditions. TheUDC 665.658.6:542.943’7:547.261:66.097.3THE DEVELOPMENT OF PURIFYING TECHNOLOGY OF PROCESS WATERS OF GAS CONDENSATE FIELD FROM METHANOLM.V. Brenchugina, A.S. Buynovsky, Z.R.Ismagilov*, V.V.Kuznetsov*Seversk State Technological Academy, Seversk*SD RAS G.K.Boreskov Catalysis Institute, NovosibirskEmail: brenchugina@sibmail.comThe possibility in principle of methanol deep catalytic oxidation in water up to MPC has been confirmed by gas chromatography method.Oxidation process of methanol contained in vat residue after regeneration stage in concentrations of 1, 5 wt. % and less, at metal oxidecatalysts at Al2O3 is considered. The basic flow diagram of closed technological cycle of methanol extraction from process waters of gascondensate fields is proposed. It consists in methanol regeneration with further deep catalytic oxidation of methanol residue quantity.

Mathematical simulation of water and methanol segregation processes at field preparation of gas condensate

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