Techno‐economic comparison of amine regeneration process with heat‐stable amine salt reclaiming units

Cho

Son³

et al. 2022

Polymers

In this work, alternative evaporation processes for PLA production were designed with economic assessment. The suggested processes are the multiple-effect evaporation (MEE) process and thermal vapor recompression (TVR)-assisted evaporation process. First, the MEE process can efficiently reuse waste heat by additional column installation, thereby reducing the steam energy consumption. The proposed MEE process involves five columns, and after the evaporation in each column, the waste heat of the emitted vapor is reused to heat steam in the reboiler of the next column. Second, the suggested TVR-assisted evaporation process utilizes an additional steam ejector and recovers waste heat from the emitted vapor by increasing the pressure using high-pressure driving steam at the steam ejector. Each alternative process was modeled to predict the steam energy consumption, and to determine the cost-optimal process; the total annualized cost (TAC) of each alternative process was calculated as evaluation criteria. In the simulation results, the alternative processes using MEE and TVR reduced the steam consumption by 71.36% and 89.97%, respectively, compared to the conventional process. As a result of economic assessment, the cost-optimal process is the alternative process using TVR and the TAC can be decreased by approximately 90%.

where TCI is calculated by summing the fixed capital cost (FCI) and working capital investment (WCI) [ 27 ]: TCI = FCI + WCI …”

Section: Resultsmentioning

confidence: 99%

Design and Economic Assessment of Alternative Evaporation Processes for Poly-Lactic Acid Production

Cho

Son³

et al. 2022

Polymers

“…To calculate the total cost of the sorting and recycling system, the total annualized cost ( TAC ) is determined. , The TAC is annualized cost, which equally occurs every year during the project lifetime and gives the same net present cost as the actual cash flow sequence. The TAC is calculated from the equivalent annual cost ( EAC ) and total product cost ( TPC ): , …”

Section: Methodsmentioning

confidence: 99%

“…To calculate the total cost of the sorting and recycling system, the total annualized cost (TAC) is determined. 56,57 The TAC is annualized cost, which equally occurs every year during the project lifetime and gives the same net present cost as the actual cash flow sequence. The TAC is calculated from the equivalent annual cost (EAC) and total product cost (TPC): 58,59 = = + TAC EAC TPC total cost (15) First, the EAC is determined from the total capital investment (TCI) and annuity factor (AF): 60 = EAC TCI AF (16) where TCI denotes the capital investment, which includes equipment cost, land cost, installation cost, etc.…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

Multiobjective Optimization of Plastic Waste Sorting and Recycling Processes Considering Economic Profit and CO₂ Emissions Using Nondominated Sorting Genetic Algorithm II

Lee

ACS Sustainable Chem. Eng.

Joo

et al. 2022

Self Cite

Plastic waste has become a severe threat to the environment as increasing amounts of plastic waste are generated every year. To solve this problem, it is crucial to increase the recycling rate of plastic waste with proper sorting and recycling processes. However, sorting and recycling costs vary depending on the specific process, and CO 2 is inevitably generated during recycling. Therefore, this study developed a novel multiobjective optimization model based on mixed-integer nonlinear programming to optimize plastic waste sorting and recycling processes according to target polymer types while maximizing net profit and minimizing CO 2 emissions. Recycling solutions were proposed using a nondominated sorting genetic algorithm, which enabled the selection of a portfolio of plastic recycling methods for each plastic type depending on the importance of the two objectives: maximum net profit and minimum total CO 2 emissions. As a result, Pareto-optimal solutions with a net profit distribution of 35− 1936 million USD/year and CO 2 emissions of 9.7−17.0 kt/year were obtained. Furthermore, the Pareto-optimal front was analyzed to provide representative optimal solutions, which can provide decision makers with a wide range of choices when determining process specifications.

“…The total cost is set to TAC, which features the contributions of the annualized capital costs and annual operating and maintenance costs; it is calculated as the sum of the equivalent annual cost (EAC) and TPC. 20 Total cost TAC…”

Section: Total Cost Of Electrostatic Precipitatormentioning

confidence: 99%

Novel waste heat and oil recovery system in the finishing treatment of the textile process for cleaner production with economic improvement

Intl J of Energy Research

Lee

Cho

et al. 2022

Self Cite

Summary In the textile industry, reactive dyeing requires large volumes of hot water, which increases cost and energy consumption. Although the waste heat of the exhaust gas from the stentering process can be recovered to reduce cost and energy consumption, fiber dust and oil mist inside the exhaust gas cause problems such as fouling and clogged pores. Hence, a novel waste heat and oil recovery system in the finishing treatment of the textile process is proposed for cleaner production with economic improvement. The proposed system comprises the following steps: (a) The exhaust gas is split by the electrostatic precipitator (ESP) at a certain ratio through optimization as its exhaust gas throughput is a key deciding variable for cost and profit. (b) A mathematical model of the overall cost, including profits from oil recovery and energy savings attributed to waste heat recovery, total capital investment, and total product cost attributed to the additional ESP installation, is designed to identify an optimal split ratio. (c) Fiber dust and oil mist are removed from the exhaust gas split at the optimal ratio using the ESP and then recycled as regenerated oil. Waste heat is recovered from the treated gas after the fiber dust and oil mist are recovered as regenerated oil through the heat exchange in the air to water heat exchanger; this recovered heat is supplied to the dyeing process to minimize the energy required for heating the water. (d) Finally, VOCs and the remaining pollutants are removed by activated carbon adsorption from the low‐temperature‐treated gas after the waste heat is recovered. These processes recover waste heat and oil and achieve process stability and efficiency improvements because of the removal of oil mist, fiber dust, and VOCs. As a result, the overall cost can be reduced by 10.2% based on the recovered waste heat and oil, and the fiber dusts, odor, and VOCs are removed by 95%, 89.86%, and 96.28%, respectively.