Design and control of energy-efficient distillation columns

김영한 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.9

Distillation is the best option for the separation of hydrocarbon mixtures, unless the boiling points of the constituents are close together. Despite being widely utilized in field applications, the high energy demand of distillation calls for efficient columns in order to save energy. The efficient divided wall column (DWC), diabatic distillation column, and internally heat-integrated distillation column (HIDiC) are introduced here, and the design and control of the columns are briefly reviewed. The practical applications of the columns in the processes of natural gas production from raw gas drawn from underground and benzene separation from naphtha reformate are presented to show the energy-saving performance of the energy-efficient distillation columns. The side-rectifier DWC reduced the heating duty of the conventional system by 5.9%, and provided a compact construction, replacing the three-column conventional system with a single column suitable for offshore application. Moreover, the controllability of DWC was improved by utilizing the side-rectifier. The benzene removal process utilizing the extended DWC lowered the heating duty of the whole conventional process by 56.8%.

Existing System Remodeling for a Fully Thermally Coupled Distillation Column

Moon Yong Lee,Young Han Kim 제어로봇시스템학회 2008 제어로봇시스템학회 국제학술대회 논문집 Vol.2008 No.10

Though many divided wall columns are implemented in field as energy-efficient distillation columns, its application is limited due to the difficulty of building a new column. A novel energy-efficient distillation system utilizing the existing columns is proposed here. The proposed can reduce the energy consumption by about 39% comparing with the existing system. And it is shown that the proposed improves the column operability over the existing. The tray numbers of the added columns have no significant influence on the composition of a side draw.

Novel hybrid-blower-and-evaporator-assisted distillation for separation and purification in biorefineries

Van Duc Long, Nguyen,Hong, Jimin,Nhien, Le Cao,Lee, Moonyong Elsevier 2018 Chemical engineering and processing Vol.123 No.-

<P><B>Abstract</B></P> <P>The production of biofuels and biochemicals from biomass-based feedstock, which is one of the most promising strategies for replacing petroleum-based resources and thus alleviating global warming, has received increasing attention in recent years. However, this strategy is energy-intensive due to the low product concentrations after transformation step. In this study, a novel hybrid-blower-and-evaporator-assisted distillation configuration (HBED) was proposed for enhancing process efficiency in bioproduct production from biomass. Several important industrial cases have been investigated to demonstrate the proposed configuration. By applying HBED, light components are partially removed in an evaporator, and the latent heat can be circulated during the process, leading to a substantial improvement in energy efficiency. A blower can increase the energy efficiency of an evaporator significantly, while the combination of an evaporator and blower can substantially reduce the size, capital cost, and operating cost of the distillation column. The results show that the proposed HBED configuration can achieve significant energy savings. Notably, the operating costs can be reduced by up to 45.4%, 26.3%, and 36.7% for the levulinic acid, 2,3-butanediol, and furfural purification processes, respectively. Furthermore, the CO<SUB>2</SUB> emissions of a conventional column and the proposed configuration are evaluated and compared.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Novel hybrid-blower-and-evaporator-assisted distillation configurations were proposed. </LI> <LI> An evaporator can reduce the size, investment and operating costs of distillation. </LI> <LI> A blower can increase the energy efficiency of an evaporator significantly. </LI> <LI> The proposed configurations can handle large quantities of water and/or solvent. </LI> <LI> Substantial saving in operating cost could be achieved in biorefineries. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Experimental evaluation of a modified fully thermally coupled distillation column

Young Han Kim,황규석,김병철 한국화학공학회 2010 Korean Journal of Chemical Engineering Vol.27 No.4

A modified fully thermally coupled distillation column replacing the conventional distillation system is introduced, and its performance is experimentally evaluated for the stable operation of the column. The existing distillation system is modified to an energy-efficient distillation column for the reduction of investment cost and energy requirement. The experiment is conducted for the separation of methanol, ethanol and n-propanol mixture using a 4-in sieve tray column. The temperatures at seven different locations of the column are measured to monitor the column operation, and the measurements indicate that the column is stably operable. The stable operation proves that neither compressor nor pump is necessary for the vapor or liquid flow between tray sections. The experimental result is compared with that of the HYSYS simulation to show how satisfactory the separation is. The modeling of temperature variation provides a successful prediction of the temperature variation.

Use of multiple inter-reboilers to achieve energy savings and improve thermodynamic efficiency of the distillation of N,N-dimethylformamide wastewater

Xiaoxin Gao,Xueming Yin,Song Yang,Deming Yang 한국화학공학회 2019 Korean Journal of Chemical Engineering Vol.36 No.1

The purification of N,N-dimethylformamide wastewater involves an energy intensive distillation process. We propose a novel energy-saving process scheme involving multiple inter-reboilers sed. In this scheme, ideal thermodynamic model non-random two liquid (NRTL) model was used to calculate the phase equilibrium using Aspen Plus platform. While the relationship between important process parameters and energy consumption by the distillation process was studied, several parameters such as the most suitable positions for the inter-reboilers and the most reasonable steam extraction rates were obtained. The feasibility was detected under the same separation duties and main technological structure. For 10wt% DMF wastewater, the inter-reboilers were installed on the 37th, 38th and 39th plates, while the corresponding heat transferred values were 3,038 kW, 91 kW and 179kW, respectively. In comparison to the conventional distillation process, an energy consumption of 77.43% and thermodynamic efficiency of 65.69% were obtained. For 20 wt% DMF wastewater, the inter-reboilers were installed on the 21st and 25th plate, while the corresponding values for the heat transferred were 1,632kW, and 1,450kW, respectively. In comparison to the conventional distillation process, the energy consumption can be reduced by 71.31%, while the thermodynamic efficiency can be improved by 47.10%.

공정시스템,이동현상,화학공정안전 : 3기의 증류탑을 이용한 에너지 절약형 증류탑의 헥산공정에의 응용

김영한 ( Young Han Kim ),황규석 ( Kyu Suk Hwang ) 한국화학공학회 2005 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.43 No.1

에너지 절약형 증류시스템의 에탄올 제조공정에의 응용

이문용 ( Moon Yong Lee ),김영한 ( Young Han Kim ) 한국화학공학회 2008 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.46 No.5

Elevated energy efficiency and reduced CO2 emissions from integrated reaction and separation for the concurrent production of ethers

Lee Jeongwoo,Lee Minyong,Kim Donggun,Shin Yongbeom,Lee Jae W. 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.12

This study aimed to design energy-efficient systems for reactive distillation to simultaneously produce methyl tert-butyl ether (MTBE) and ethyl tert-butyl ether (ETBE) from mixed feeds of methanol and ethanol. In this work, two new designs are proposed. One is the individual production of each ether, involving two reactive distillation columns after feed alcohol separation, while the other for the co-production of both ethers in a single reactive distillation column without the alcohol separation. Rigorous simulations of the two proposed systems were conducted with varying ratios of the two alcohols in actual process streams. When the methanol feeding was dominant, the co-production system exhibited better performance than the individual ether production system. This was due to the lower temperatures inside the alcohol separation column, resulting in a lower relative volatility of methanol and increasing the heat duty in the alcohol separation column. However, when the amount of ethanol was higher than that of methanol, the individual production system outperformed the co-production system. This was attributed to the unfavorable reaction equilibrium of ETBE production, leading to a high internal flowrate in the co-production reactive distillation column. The external heat integration of each design can bring further reduction in energy consumption and CO2 emissions, but the results follow the same dependence on the feed alcohol ratio.

Application of a divided wall column for gas separation in floating liquefied natural gas plant

전호환,김영한 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.7

A divided wall column (DWC) has widely been utilized as an energy-efficient distillation column. When it is applied to the offshore floating liquefied natural gas (FLNG) plant, its compactness can provide a favorable distillation system for the unconventional plant on top of its high energy efficiency. We investigated the design characteristic, cost evaluation and operation difficulty of the DWC at its utilization in the FLNG plant. The results from the HYSYS simulation of the DWC were compared with those of the conventional distillation system, and the following was found from the study. The DWC replacing the depropanizer and debutanizer of the conventional distillation system requires 12.5%less investment cost. While the saving of 25% in steam cost is expected from the DWC, the total utility cost including the refrigerant cost is reduced by 20.2% due to the lower cost reduction of refrigeration in the DWC.

Energy saving and thermodynamic efficiency of a double-effect distillation column using internal heat integration

김영한 한국화학공학회 2012 Korean Journal of Chemical Engineering Vol.29 No.12

The existing internally heat-integrated distillation column with the problem of utilizing a compressor is modified to propose a new heat-integrated distillation column without the compressor. Two identical columns of a conventional binary distillation are implemented to the heat integration. The energy used in the reboiler is recovered by the internal heat integration between the stripping section of one of the columns at lower pressure and the rectifying section of the other higher pressure column. The heat integration is similar to double-effect distillation, but internal heat integration requires less pressure elevation. The performance of energy saving and thermal efficiency improvement of the proposed system is evaluated with the two examples of the benzene-toluene and methanol-ethanol processes. The performance comparison indicates that the proposed system requires 17.4% less of reboiler duty for the benzene-toluene process and 15.8% less of heating duty for the methanol-ethanol process. The thermal efficiencies are 16.3% and 23.8% for the benzene-toluene and methanol-ethanol processes, respectively. Elimination of the compressor makes the column operation easy and the separate reboilers and condensers for the two columns in the proposed system provide flexible control, when the controllability of the proposed system is compared with that of the existing internally heat-integrated distillation column.