Chemical Engineering & Technology最新文献

Microalgae with increased amount of biomass and lipid yield are crucial for biodiesel production. Mixotrophic cultivation has prominence for increasing the micro-algal cell concentration and hence the volumetric productivity owing to independent utilization of both the photo-assimilation of CO₂ and oxidative assimilation of organic carbon sources. In this study, Ankistrodesmus sp. IFRPD 1061 was examined under various concentrations of sodium acetate for concentration and productivity of biomass and lipid, lipid contents (LCs), and fatty acid profiles. The optimum condition was obtained at Day 21 with 10 mM sodium acetate, which gave 6.940 ± 0.057 g L⁻¹ biomass concentration, 327.619 ± 2.020 mg L⁻¹ day⁻¹ biomass productivity, 2.795 ± 0.191 g L⁻¹ lipid concentration, 131.955 ± 9.275 mg L⁻¹ day⁻¹ lipid productivity, and 40.286 % ± 3.079 % w/w LC. The optimum condition (10 mM sodium acetate) in an open pond cultivation attained maximum values at Day 14, that is, 0.575 ± 0.004 g L⁻¹ biomass concentration, 38.161 ± 0.076 mg L⁻¹ day⁻¹ biomass productivity, 0.203 ± 0.002 g L⁻¹ lipid concentration, 13.440 ± 0.197 mg L⁻¹ day⁻¹ lipid productivity, and 35.219 % ± 0.585 % w/w LC. The lipids recovered from mixotrophic micro-algae were primarily unsaturated fatty acids, which are appropriate to produce biodiesel. The results revealed that a 10 mM sodium acetate concentration can enhance lipid accumulation within algal cells.

For multi-enzymatic cases, the determination of the batch reactor (BR) optimal operating policy often translates into a difficult multi-objective problem. Exemplification is made here for the enzymatic reduction of D-fructose to mannitol by using the mannitol dehydrogenase (MDH) enzyme and nicotinamide adenine dinucleotide (NADH) cofactor, with in situ regeneration of NADH at the expense of formate degradation by using the FDH enzyme. This paper presents an original rule to in silico generate the problem solution, by using the Pareto optimal-front approach with accounting for pairs of competing economic goals and constraints. The optimal BR is then compared to an optimal fed-BR (FBR), or a series of equal BRs (SeqBR). As proved, the Pareto-optimal front alternative is an advantageous option, compared to the classical nonlinear programming technique, being simple to apply, by considering pairs of opposite objective functions. In the present case study, the Pareto-optimal BR operating mode predicts an M-productivity 1.5x better than those of an optimized FBR, with comparable enzymes consumption. The MDH consumption of this Pareto-optimal BR is 10x smaller than an optimal SeqBR, and 130x smaller vs. heuristic (sub)optimal BR.

Heavy metals and dyes cause serious harm for water environment, geopolymer materials with the large pores and specific surface area, and easy modification of pore surface have received extensive attention in wastewater treatment. Herein, using loess-clay (LC) as natural mineral materials, we developed an eco-friendly geopolymer of loess-clay (GpLC) with excellent adsorption properties and promotion plant growth was prepared by alkali excitement. Its morphology and structure were exhibited by scanning electron microscopy, Fourier transform infrared spectroscopy, XRD, and Brunauer–Emmett–Teller. Moreover, its adsorption property for removing metal ions and different dyes was measured, and the adsorption kinetics and thermodynamics were investigated. GpLC presented excellent adsorption ability for Pb²⁺, which the removal rate got to 98.7 %. It had the universality of removing organic pollutants, and the removal rate reached to 98.0 %. It was dominated chemisorption and single-layer adsorption, which GpLC conformed to quasi-second-order adsorption kinetics, and being more consistent with Langmuir isothermal model. Furthermore, it was found that GpLC could promote growth of crops as it contain P and K element with essential element of plants. In summary, it provides insights and strategy for developing a kind of eco-friendly functional materials with strong adsorption capacity and promoting plant growth, and it is an effective method for reusing loess resources.

This study sought to evaluate the influence of five macronutrients (acetate, calcium, sulfate, nitrogen, and phosphate) on the cell growth and heterologous mCherry protein production by Chlamydomonas reinhardtii. In the first step, three nitrogen (N) sources were tested (NH₄NO₃, NaNO₃, and NH₄Cl), and NH₄NO₃ was selected as N source for the following step, due to the best results for mCherry protein production. In the second step, a central composite design 2⁵ was employed to evaluate the effect of the five macronutrients. Although all nutrients had effect on maximum biomass concentration, only acetate, nitrogen, and phosphate showed to influence mCherry protein production. By employing the experimental design with small-scale culture in multiplates and multivariable regression, it was possible to achieve 12 % increase for recombinant protein production.

The iron and steelmaking industries play a significant role in the manufacturing sector but result in significant greenhouse gas emissions. Biochar has recently gained attention as a potential substitute for coal in metallurgical processes due to its carbon capture potential. This review explores the potential of biochar as a sustainable substitute for coal in steelmaking industries. Notable research works have shown that substituting biochar in amounts ranging from as low as 5 % to as high as 50 % can be feasible and beneficial in processes such as coke making, iron sintering, blast furnaces, and electric furnaces. The information presented in this review can be applied to create sustainable and competitive alternatives to fossil fuels to help decarbonize metallurgical industries.

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Liquefied natural gas (LNG) regasification terminals have specification that necessitates adjustment of heating value of LNG feed. One strategy to reduce heating value is to separate heavier hydrocarbons from LNG by utilizing LNG cold energy. The amount of cold energy utilized in recovering heavy hydrocarbon is much less resulting in wastage of remaining cold energy. To reverse this wastage, we propose a polygeneration process that encompasses an organic Rankine cycle to generate electricity and refrigeration for cold storage warehouse cooling and data center cooling by utilizing remaining cold energy. Based on process simulation and optimization, we found that a significant amount of cold energy is utilized resulting in an avoided CO₂ emission, thereby enhancing sustainability of an LNG regasification terminal.

Operators in modular process plants face new demands due to features like increasing automation and digitalization combined with an architecture allowing for reconfigurations in short time spans. However, operators must be able to master process control tasks at all times. For research purposes on topics like supporting operators in their performance in process control of modular process plants, this article aims at developing scenarios of such plants. Based on three conceptual levels describing the relation of chemical processes and their modularized realization and a neutralization process as use case, four scenarios were developed. Having the common task to increase the throughput, the scenarios differ in terms of complexity and constraints that need to be considered for process control.