Low-temperature Separation Research Articles

A novel method for efficient recovery of boron from boron-bearing iron concentrate: Mineral phase transformation and low-temperature separation via super-gravity

As the tailings of complex paigeite ore through the multistep magnetic separation process, the boron-bearing iron concentrate is mainly used in the ironmaking process for the recovery of iron, while the boron is hard to be recovered. In this study, a novel method was proposed for efficient recovery of boron from boron-bearing iron concentrate through mineral phase transformation and low-temperature separation via super-gravity. The mineral phase transformation of boron-bearing iron concentrate in the reduction process as a function of the temperature mainly included three stages, Stage I: The iron minerals were fully reduced to metallic iron at 1373–1423 K, Stage II: The boron was mainly transformed from suanite (Mg2B2O5) into the boron-rich slag with a high concentration at 1473–1523 K, Stage III: The forsterite (Mg2SiO4) was further melted into slag and some boron was also reduced and entered into liquid iron which caused a significant decrease in boron concentration in the slag at 1573–1623 K. Thus, low-temperature separation of boron-rich slag from the iron phase was conducted at 1523 K via super-gravity. The boron was efficiently recovered into the boron-rich slag with a high recovery of 98.24 % and a high mass fraction of B2O3 of 39.27 wt%, and almost all boron was enriched into a form of suanite. Low-temperature separation greatly improves the recovery of boron in boron-rich slag and prevents boron from entering metallic iron, and also improves the activity of boron-rich slag for sustainable utilization.

Economic Analysis of Separation Unit of Methanol to Propylene Production Based on Optimization of Refrigeration Cycles Using Pinch and Exergy Analysis

In this study, optimization and economic analysis of the separation of light gases in the methanol to propylene, MTP, process along with refrigeration cycles design are performed, by using pinch and exergy analysis. In the course of the separation process optimization and refrigeration cycles design, by using a Visual Basic, VB, program and genetic algorithm, GA, rigorous distillation simulation is carried out, then streams information is employed to find optimum temperature levels, corresponding to tower condenser temperature, by minimizing the areas between the Exergy Grand Composite Curve, EGCC, and constant temperature levels of refrigeration cycles. Economic calculations were performed to obtain the lowest total annual cost, TAC, for refrigeration cycles, towers and other equipment. Two cases of the direct and indirect sequences are examined through the developed framework, inspection of their results represents that the operational cost has a significant contribution to the TAC. As a result, heat integration would reduce it by nearly 60%. Also, scrutinized analysis of the optimization results, especially by considering the TAC and its contributions, for the direct and indirect sequences, leads to the conclusion that indirect sequence would exhibit lower cost for light gas separation. The framework represented herein paves a way to the systematic design of integrated low-temperature separation processes with refrigeration cycles.

Aerodynamic Characteristics of Supersonic Separator for Natural Gas Processing

Natural gas is a key energy source to achieve the carbon peaking and carbon neutrality goals in China. Dehydration and de-hydrocarbon process is crucial for pipeline transportation of natural gas since water and hydrocarbons in the natural gas would condense to cause corrosion and freeze-blockage in the pipeline. The supersonic separator is innovative low-temperature separation equipment characterized by a simpler equipment structure and higher refrigeration efficiency than the traditional device. In this paper, the numerical analysis is employed to predict the performance of the supersonic separator. The results show that this separator can reach an advanced level compared with others. The separator cannot start-up as the inlet-outlet pressure ratio is lower than1.29, and the minimum pressure ratio needed for normal work is 1.39. Under normal operating conditions, total pressure loss is about 25.4%, the minimum temperature is about 213K, and the mean rotation speed is about 170m/s.

Low-Temperature Flotation Separation of Diaspore from Kaolinite by Using a Mixed Collector

In this paper, the effect of a new mixed collector sodium oleate (NaOl)/tert dodecyl mercaptan (TDM) on the separation of diaspore and kaolinite at 283 K was investigated. The molar ratio of NaOl to TDM is 8:2. The properties of the mixed collector and its adsorption mechanism on diaspore and kaolinite were studied by surface tension measurements, Zeta potential determinations and XPS analysis. The flotation results show that the mixed collector NaOl/TDM has a good collection ability for diaspore and a good selectivity for kaolinite at low temperatures. Therefore, the mixed collector NaOl/TDM can effectively separate diaspore and kaolinite under alkaline conditions at 283 K. The results of surface tension measurements show that the molecular density, hydrophobic association ability and collection ability of the mixed collector NaOl/TDM are better than those of the single collector at 283 K. In addition, the formation of a micelle effect of the mixed collector NaOl/TDM has a synergistic effect, which improves the reagent activity at low temperatures with the flotation effect enhanced. The results of the Zeta potential determinations and XPS analysis show that the total adsorption capacity of the mixed collector NaOl/TDM on the surface of the diaspore at low temperatures is higher than that of NaOl, and the adsorption capacity on the surface of kaolinite is similar to that of NaOl. The mixed collector NaOl/TDM may be adsorbed on the surface of diaspore and kaolinite by a hydrogen bond at 283 K.

Lattice Relaxation Forward Negative Coulomb Drag in Hopping Regime

Quasi-particle formed by electron and the dressed deformed lattice is important to accurately interpret the properties of various disordered/amorphous materials. However, a unified understanding of the drag effect, in particular the negative Coulomb drag in hopping systems, remains an open challenge. This work proposes a theoretic framework to account for both positive and negative Coulomb drag in dual-1D-hopping systems by considering both the electron-electron correlation and the electron-phonon correlation. It is found that lattice relaxation in the active line of the hopping system may give rise to an inverse energetic pumping force in the passive line, causing negative Coulomb drag. The mobility of the negative coulomb drag can approach the scale of 10−5cm2V−1s−1, especially at low temperature, high carrier-density, and narrow inter-spacing separation. More intriguingly, the positive drag could be recovered by varying the energy fluctuation and suppressing the electron-phonon interactions, but with a much lower magnitude. Our work could serve as a universal model for the Coulomb drag effect in the hopping system.

Intermittent direct joule heating of membrane surface for seawater desalination by air gap membrane distillation

Air gap membrane distillation (AGMD) is a low-temperature separation process applied commonly to desalination of (hyper)saline feeds. The low energy efficiency of heating the bulk feed solution to drive vapor transport in MD must be addressed through novel materials and techniques. In this work, we introduce the concept of intermittent electrical heating at the membrane surface using electrically conductive carbon nanotube structure (CNS) films pressed on commercial polypropylene (PP) membranes. First, the Joule heating effect was optimized by varying the mass loading of the CNS layer between 1.4 and 4.2 mg cm −2 . The effect of mass loading on porosity, electrical properties and cross-sectional morphology of the CNS layer was also investigated. Electrical conductivity of CNS films increases with increasing CNS mass loading. A CNS loading of 1.4 mg cm −2 yielded the highest electrical resistance, which translated into higher Joule heat generation, and highest steady-state temperature in response to applied current. When an alternating current of 2 A was passed through the CNS films in air, the maximum surface temperature achieved was 184 °C, 126 °C and 100 °C at CNS loadings of 1.4 mg cm −2 , 2.8 mg cm −2 and 4.2 mg cm −2 , respectively. Maximum surface temperature and spatial temperature distribution of CNS films were verified using a steady-state thermal-electric simulation. CNS films exhibited rapid thermal cycling between on and off states, due to their low thermal mass, with low thermal time constants for both heating and cooling. CNS film with a loading of 1.4 mg cm −2 was then pressed onto a commercial PP membrane and applied to AGMD for seawater desalination, with the conductive layer in direct contact with the feed solution. Intermittent heating was carried out by passing a current of 2 A for 10 min at 20 min intervals, for 10 cycles. Feed outlet temperature increased by > 9 °C during each cycle, which improved average permeate flux by 78%. While specific thermal energy consumption increased by 34%, a 25% enhancement was found in GOR, indicative of higher thermal energy efficiency. We have demonstrated the effectiveness of intermittent membrane surface heating for simultaneous performance enhancement and improved energy efficiency for seawater desalination using MD. • Direct surface heating applied to lab-scale air gap membrane distillation system for seawater desalination. • Carbon nanotube nanostructures coated onto hydrophobic membrane to enable Joule heating. • Intermittent application of electrical field improves GOR by 25% and productivity by 78%. • Long-term application of high-grade electrical energy not required.

Multifunctional Equipment for Low-temperature Separation of Food Solutions Based on The Effect of “Thermal Paradox”

The analysis of studies devoted to food solutions separation was carried out. The evolution of cryoconcentration technologies is analyzed, including the research works of the authors in the field of the block freezing plants. The purpose of the work is to reduce energy costs in block freezing plants and to intensify the process of the ice block formation. A hypothesis states that energy efficiency can be improved by recycling ice, using its energy to supercool the refrigerant before throttling. To intensify heat and mass transfer during crystallization, a scientific and technical idea for the implementation of the "thermal paradox effect" is proposed. The essence of the effect is that, with a certain combination of design and operating parameters of a block freezer, the growth of an ice block leads to a decrease in the total thermal resistance in the circuit "refrigerant — block freezer's wall — ice block — solution". The most significant result of the work was that it proved the possibility to harmonize the design and operating parameters and organized the process of separation the solutions into ice and concentrate while minimizing systemic cold losses, and, and thus the ways were proposed for developing the freezing concentration technique. The scientific significance of the obtained results lies in the fact that a new principle of efficient use of the ice block energy was proved in the work, and a new effect was obtained, which it was referred to by the authors as the "thermal paradox". The practical significance of the work was that a multifunctional freezing unit with ice recycling and frequency control of the compressor drive was created.

Oiling low temperature separation process for dehydration and de-hydrocarbon of natural gas and practical application

In order to reach the specification of water and hydrocarbon dew point, most of the water and C3 and heavier hydrocarbons need to be removed from natural gas. Low Temperature Separation (LTS) process by throttling expansion or refrigeration is commonly employed for natural gas dehydration and de-hydrocarbon as the most economical method. In case of some special natural gas which contains small quantity of the wax (mainly C16+ components), wax is easily deposited in the throttling facilities that leads the blockage of internals of low temperature separator and affects safety operation. Oiling LTS process, a novel process for this kind of special natural gas, is investigated in this work. The oil is injected into the natural gas to reduce the wax precipitation temperature and thus to avoid wax blockage. It is a kind of improvement and innovation process based on conventional treatment ones. According to the simulation analysis and practical application for a natural gas processing plant in Aksu, China, the new process presents good performance. Also, it is found that the best injection point is at the inlet pipe of raw gas pre-cooler and the optimal injecting stream is from the three-phase separator. Also, the injection oil flowrate is determined by refrigerating temperature and the concentration of wax. Meanwhile, the detailed economic analysis of oiling LTS process was involved. Comparing the conventional process, its adding investment is around 423,583$ accounting on 5% total capital cost of this unit. However, from the comprehensive aspects, this optimized process presents a good economic benefit.

Iron Recovery from Iron Ore Tailings by Direct Hydrogen Reduction at Low Temperature and Magnetic Separation

In this work, we describe a sustainable alternative to recover iron from two iron ore tailings (IOT) using hydrogen reduction at relatively low temperatures followed by magnetic separation. X-ray powder diffraction (XRD), inductively coupled plasma (ICP), atomic absorption (AA), Mössbauer, scanning electron microscopy (SEM/EDS), Raman and thermogravimetry (TG) analyses indicated that the Fe oxide present in the IOTs (sandy tailing (ST) and mud tailings (MT)), can be reduced with H2 at 500 ºC to produce α-Fe. Upon magnetic separation the mud tailing produced a 77 wt.% magnetic fraction increasing the Fe content from 19.2 to ca. 56 wt.% of Fe. On the other hand, the sandy tailing resulted in a 15 wt.% magnetic fraction increasing the Fe content from 19.2 to 70 wt.%. These results indicate that up to 86% of iron can be recovered from the IOT wastes already in the metallic form which can be very interesting for the steel industry.

Progress on the regeneration unit of a reverse electrodialysis heat engine

The reverse electrodialysis heat engine (REDHE) has emerged as a promising technique in the waste heat harvest field due to its ability to convert very low-grade waste heat (below 100°C) into power. A REDHE consists of a regeneration unit and a reverse electrodialysis (RED) cell unit, which are in charge of heat to the salinity gradient energy-conversion process and salinity gradient to the power conversion process, respectively. Despite the fact that a regeneration unit accounts for 60% to 70% of the energy destruction of the overall system, most of the research conducted on RED units has barely reviewed the regeneration units. Therefore, the evaluation of regeneration units is necessary. This work provides a review of the research progress made on regeneration units. In this paper, a systematic review of the operating fluids and regeneration methods employed in a regeneration unit is provided. Also, the effects of solvent and solute characteristics on the performance of a regeneration unit and the overall system and the working fluid selection principle are investigated. Additionally, the disadvantages of the methods employed in existing and future development directions are analyzed. Finally, other applications of the heat engine (apart from power production) are presented. Since the RED technology has been primarily used to recover blue energy, its operating fluid is the NaCl aqueous solution. However, the NaCl solution is not suitable for the REDHE technology. Specifically, it is not suitable for the regeneration process of a regeneration unit because the latent heat of water vaporization is huge, which leads to huge energy consumption in the regeneration module. Also, the power generation performance of the NaCl solution is poor, and the maximum power density is only 1/8 of that of the LiBr solution, resulting in the low efficiency of the overall system. Since the REDHE technology is used to recover low-grade heat energy, its regeneration unit adopts a low-temperature separation technology. The main regeneration methods used are distillation separation and membrane distillation separation. The distillation separation technology is the most mature, but it consumes more energy and has a high maintenance cost. On the other hand, the regeneration temperature of the membrane distillation technology is low, but the required technology is difficult to apply, and the cost of the membrane is high. It should be noted that the biggest difference between the REDHE and traditional separation technologies is that the former aims to build an optimal concentration gradient for the battery cells, rather than to perform the complete separation of components. For example, the seawater desalination process assumes that the separated water is pure water. For an RED cell, if the diluted solution is pure water, the battery performance will decline rapidly due to the decrease in the solution conductivity. Currently, more research work has been conducted on various separation technologies and less on the coupling of regeneration technology with power generation technology. Future research should focus on the coupling of the thermal separation module with the power generation module. Although the objective of the REDHE technology is to utilize the industrial waste heat, the heat-source temperature can be very low (down to 40°C), which means that the technology can also be used for low-grade heat recovery such as geothermal and solar energy. At the same time, although the technical efficiency of the REDHE is low, its power generation process is accompanied by electrode reaction and temperature change. This means that during power generation, the REDHE can also be used for sewage treatment, organic matter degradation as well as waste acid and alkali recovery.

Development of extreme regulator of separation moisture from the gas stream

Object of study: Automation of control of technological parameters of the process of low-temperature separation (LTS) of moisture from a gas stream.
 Investigated problem: Improving the efficiency of the separation process when preparing gas for transportation through the consumption network. Development of hardware and software tools that provide automation of the process of regulating flow parameters under conditions of action of time-varying disturbances.
 Main scientific results: A criterion for controlling the LTS process of a gas flow is formulated. The difference in the dynamic characteristics of the processes occurring during the separation of moisture makes it possible to effectively use a two-circuit control system. The perspective of using extreme regulators (ER) of the process, which is characterized by time delays between the input of the object and its output, is substantiated. The use of ER ensures the stability of the control process under the influence of disturbances in the parameters of the gas flow.
 In the MATLAB environment, an ER model has been developed, in which a step-type algorithm is used, which provides an increase in the efficiency of the LTS process in accordance with the selected criterion
 The area of practical use of research results: The scope of use of the research results are automation objects that need continuous automatic tracking of the changing settings of the process parameters regulators. The studies carried out make it possible to use the proposed regulator in various technological installations for drying gas and air (with appropriate identification of the parameters of the object).
 Innovative technological product: Based on the formed criterion for controlling the LTS process, which is aimed at increasing the efficiency of the LTS process of moisture from a gas flow, a microprocessor-based step-type ER has been developed. Preliminary tests of the regulator show that it can be implemented on commercially available program logic controllers on the market.
 Scope of application of an innovative technological product: The considered ER can be used to construct control systems for oil and gas transportation processes, which require adaptation and optimization modes to flow parameters. In this case, the need for adaptation is dictated by changes in flow parameters over time.

Effect of additive structure on the performance of biodiesel fuel winterization

The effects of additive structure on the separation of saturated fatty acid methyl esters (FAMEs) from FAME mixtures by winterization were investigated. Six sorbitan derivatives, seven palmitate derivatives, and sorbitan monopalmitate, which is known to improve the low-temperature separation of FAME mixtures, were studied. A model FAME mixture was prepared by blending saturated FAME (methyl palmitate) and unsaturated FAME (methyl oleate). Sorbitan derivatives that had fatty-acid groups with the same carbon chain length as the main saturated FAME in the FAME mixture improved the separation significantly. Shorter chain lengths and unsaturated fatty acid groups did not promote the winterization of FAME mixtures because their interactions with the main saturated FAME were too weak. Cyclic structures and hydroxy (OH) groups in the ester groups of the palmitate derivatives were found to be essential for preventing crystal growth and liquid contamination of the recovered solid phase. Cyclic structures affected the appearance of the FAME mixture during winterization, and the presence of OH groups affected the separation factor and the cloud point (CP) of the recovered liquid FAME. Span40, which has palmitate and sorbitan groups, was found to be the most effective additive for mixtures containing approximately 50 wt% methyl palmitate. The CP of the recovered liquid decreased 4–9 K, and the separation factors were between 3.6 and 7.5. These results will be useful for the separation and purification of saturated rich-FAME mixture such as palm, lard, mahua, neem, and jatropha biodiesels.

ОЦЕНКА ВЛИЯНИЯ ТЕРМОБАРИЧЕСКИХ УСЛОВИЙ НА ЭФФЕКТИВНОСТЬ ПРОЦЕССА НИЗКОТЕМПЕРАТУРНОЙ АБСОРБЦИИ ПРИ ПРОМЫСЛОВОЙ ПОДГОТОВКЕ ГАЗА НА МЕСТОРОЖДЕНИИ КРАЙНЕГО СЕВЕРА

Актуальность. Деэтанизированный газовый конденсат является ценным сырьем для нефтепереработки и нефтехимического производства, поэтому увеличение степени его извлечения из газа газоконденсатных месторождений на промысловых установках является актуальной научно-технической задачей. Цель: обосновать возможность увеличения выхода нестабильного конденсата-фракции С3+ из потока газа на действующей промысловой установке комплексной подготовки газа и конденсата одного из нефтегазоконденсатных месторождений Крайнего Севера за счет оптимизации рабочих параметров процесса низкотемпературной абсорбции. Объект: промысловая установка низкотемпературной абсорбции. Метод: моделирование процессов сепарации и низкотемпературной абсорбции в среде программного комплекса «PetroSim». Результаты. Исследовано влияние давления и температуры, расхода газа, удельного расхода и состава абсорбента – нестабильного конденсата, на эффективность процесса подготовки газа и конденсата на компьютерной модели промысловой установки низкотемпературной абсорбции и низкотемпературной сепарации. Показано, что использование процесса низкотемпературной абсорбции на последней ступени сепарации для рассматриваемого состава сырого газа обеспечивает выход целевой фракции С3+ примерно в 2 раза больше в широком диапазоне давлений и температур по сравнению с процессом низкотемпературной сепарации. Обоснована возможность увеличения степени извлечения в товарный нестабильный конденсат фракции С3+ на последней ступени сепарации в процессе низкотемпературной абсорбции на 21 % только за счет оптимизации режимных параметров работы установки без изменения технологической схемы. При часовом расходе сырого газа 225 тыс. м3/час оптимизацией термобарических параметров процесса низкотемпературной абсорбции - изменением давления с 3,75 до 5,0 МПа и температуры с минус 30 до минус 35 °С, извлечение фракции С3+ в нестабильный товарный конденсат повышается на 6,6 г/м3 сырого газа без модернизации технологической схемы установки, т. е. на 35 т/сутки с соответствующим сокращением ее уноса с товарным газом. При «утяжелении» компонентного состава абсорбента путем снижения давления в разделителе нестабильного конденсата первой ступени сепарации степень извлечения фракции С3+ в товарный нестабильный конденсат в низкотемпературном абсорбере повышается на 25 %, т. е. еще на 6,6 г/м3, или 7 т/сутки дополнительно с соответствующим дальнейшим сокращением ее содержания в товарном газе. Но реализация такого режима уже требует минимальной модернизации установки низкотемпературной абсорбции путем врезки насоса в технологический трубопровод подачи нестабильного конденсата орошения с разделителя Р-1 в низкотемпературный абсорбер, которая окупаема в короткие сроки.

Coulomb drag study in graphene/GaAs bilayer system with the effect of local field correction and dielectric medium

The drag resistivity is measured numerically for electron-electron (e-e) and electron-hole (e-h) coupled layer system composed of single layer graphene and two-dimensional (2D) GaAs layer separated by a barrier. The system is studied within the model of random phase approximation (RPA) and taking into account the static local field correction (LFC) and layer thickness effects in the Ballistic/Boltzmann regime. We have shown analytical expressions of non-linear susceptibility function and effective interlayer Coulomb interaction for non homogeneous dielectric environment at low temperature, high density and large interlayer separation limit. Exchange and correlation effects enhanced the drag resistivity by considering the static local field correction. Width of the layer and interlayer distance dependent local form factors (LFF) are obtained from the solution of the Poisson equation for a multi-layer dielectric medium. The effects of LFC and LFF are the function of bare inter- and intra-layer potential, which enhances the drag resistivity compare to simply measured RPA results. Enhanced drag resistivity also measured for e-h bilayer system where the hole layer is considered for 2D GaAs (drag layer), cause of larger effective mass of hole compare to the electron. Similarly, e-e and e-h bilayer system measured the enhanced drag resistivity due to LFC effects.

Coulomb drag study in electron-electron bilayer system with a dielectric medium

Abstract We have theoretically investigated the drag resistivity in electron-electron bilayer system by using the random phase approximation (RPA) for weakly interacting regime, at low temperature, high density, and large interlayer separation limit. We show analytical expressions by using long wavelength (low frequency regime) expansion of response function in Boltzmann regime and bare Coulomb interaction for non homogeneous dielectric environment which make the system interested and different compare to others. The influence of electron-electron bare inter and intra layer interaction are considered static cause of static local form factor (LFF) approximation in coupled layer system of non homogeneous dielectric background. The effective dielectric function and LFF are obtained from the solution of the Poisson equation of a three-layer dielectric medium. The effects of local form factors are included in bare inter and intralayer potential, yields the dependency of layer separation and dielectric constants of the materials. Drag resistivity dependency is measured numerically with respect to temperature T and density n and compared to other 2DES, which yields to possess the same qualitative and quantitative behaviour compare to bilayer system of homogeneous dielectric environment.

Dehydration and low temperature separation technologies for liquified natural gas production via electrolysis: A systematic review

• Low temperature gas upgrading techniques are discussed. • Processed gas is hydromethane obtained through electrolysis and methanation. • Techniques are reviewed to meet LNG quality requirements and grid EN 16726 standard. • LNG can be used in transport application or in the gas grid after regasification. Power-to-fuel applications represent a relevant option among energy storage technologies to overcome grid issues, such as overgeneration due to renewable energy sources exploitation. The production of raw hydromethane mixture, through water electrolysis and, downstream, methanation, can be integrated in power to liquefied natural gas systems allowing the exploitation of liquefied natural gas as energy carrier. It enables multiple uses linking multiple sectors (e.g. transport, industry, electric power production). Cryogenic separation techniques could be implemented aiming to an enhanced overall conversion efficiency. Key of this systematic review is the identification and analysis of the gas upgrade technologies that, moving from the raw hydromethane mixture, guarantee a final liquefied natural gas composition meeting the requirements imposed by: (i) grid injection and use in conventional endothermal engines after regasification (2 vol% H 2 ); (ii) particular sensitivity of the natural gas liquefaction process to the presence of water (< 0.1 ppm) and CO 2 (< 50 ppm). A critical review for hydromethane upgrade which faces the issues of real utilization is not available in literature, thus it is provided in this work. The paper is structured in two main parts: in the first gas dehydration techniques are described, while the second focuses on CO 2 separation, highlighting advantages and application limits of low temperature techniques to the case of study. In the conclusions, a process optimal configuration is discussed for the production of liquefied natural gas from renewable electricity, as energy carrier suitable for multisectoral applications and compliant with scenarios of high renewable energy penetration.

The process of production of liquefied methane - the component of rocket propellant

The use of new fuel components, such as LNG or liquefied methane, in rocket-space, aviation and other special-purpose engineering is promising. On the basis of these fuel components it is possible to provide a number of technical and tactical parameters of aircrafts, which are not achievable when using standard fuels. Considered were the cryogenic systems developed by PJSC "Cryogenmash" for natural gas liquefaction with liquid methane recovery by the method of low-temperature condensation, stage separation and rectification. The second method allows to reduce the content of not only low boiling but also high boiling liquids in methane liquefied.

Increasing the Efficiency of Hydrocarbons С5+ Extraction from the Gas of Condensate Fields by a Low-Temperature Absorption Process

Absorption extraction of C5+ hydrocarbons from formation gas of gas-condensate fields at the level of temperature of from –25 to –30°C was simulated. The following conditions were recommended during realization: absorbent by physical-chemical characteristics corresponding to hydrocarbons С9/С10, four theoretical contact stages in the absorber, and partial expenditure of absorbent of 20–30 g/m3. Techniques of low-temperature absorption and low-temperature separation were compared. Parameters were determined that allow developing a scheme of a process with the increased degree of extraction of hydrocarbons С5+ (over 99%), which are valuable petrochemical materials.

Experimental Investigation of Low-Temperature CO2 Separation for Carbon Capture in the Cement Industry

Experimental Investigation of Low-Temperature CO2 Separation for Carbon Capture in the Cement Industry

ИЗВЛЕЧЕНИЕ ОСТАТОЧНОГО СОДЕРЖАНИЯ ВЫСОКОМОЛЕКУЛЯРНЫХ УГЛЕВОДОРОДОВ ПРИ ПРОМЫСЛОВОЙ ПОДГОТОВКЕ ГАЗА

Актуальность исследования обусловлена необходимостью повышения эффективности выделения ценных компонентов из природного газа в промысловых условиях. Существующие технологии подготовки газа газоконденсатных месторождений характеризуются низкой степенью извлечения пропан-бутановой и этановой фракций. Известно, что природные газы валанжинских и ачимовских отложений содержат большое количество необходимых для нефтехимической продукции компонентов. Промысловая подготовка природного газа газоконденсатных месторождений обычно базируется на технологии низкотемпературной сепарации, где извлечение жидких углеводородов из потока газа происходит путем снижения температуры дросселированием с последующим разделением газовой и жидкой фаз в самостоятельных сепараторах. Технология имеет низкий КПД и ограничена зависимостью от высоких давлений. Рассматривается вопрос дооснащения установок комплексной подготовки газа малогабаритным высокопроизводительным оборудованием, обеспечивающим глубокое охлаждение среды и одновременное разделение на компоненты. Цель: теоретическое исследование особенностей высокоскоростных процессов подготовки природного газа, провеcти численный эксперимент, в ходе которого установить влияние основных параметров оборудования на эффективность отделения высокомолекулярных составляющих от метана. Объекты: установки комплексной подготовки газа газоконденсатных месторождений, среднестатистические значения состава газа, критических параметров и производных величин, которые соответствуют условиям северных месторождений. Методы: построение математической модели, учитывающей компонентный состав газа, определение распределения температуры, давления, скорости, плотности и числа Маха газа в высокоскоростном сепараторе с разделением на компоненты. Результаты. Предложена технология получения более низких температур, необходимых для комплексной подготовки газа газоконденсатных месторождений. Она реализована на базе газодинамической высокоскоростной технологии с применением трубки Ранка–Хилша и сопла Лаваля. Установлены расчетные зависимости извлечения пропан-бутановой и этановой фракций от достигаемых низких температур.