Total Process Cost Research Articles

Impact of stochastic industrial variables on the cost optimization of AISI 52100 hardened-steel turning process

An optimization problem of the AISI 52100 hard-steel turning process is examined. A new approach is presented in which not only the machine parameters (cutting speed, feed rate, and depth of cut) but also the stochastic industrial variables of setup time, insert changing time, batch size, machine and labor costs, tool holder price, tool holder life, and insert price are considered. By representing each of these variables by a given probability distribution, the goal was to analyze their impact on the total process cost per piece (Kp). Experiments were carried out following a central composite design to model tool life (T), average surface roughness (Ra), and peak-to-valley surface roughness (Rt) using a response surface methodology. Then, stochastic programming was used to model Kp’s expected value and standard deviation. The approach to the optimization problem aimed to maximize the probability for the cost to be less than a target value, subject to the experimental space and to maximum values of both Ra and Rt. The results were optimal values for the cutting conditions that provide a suitable confidence interval for Kp. The most-significant industrial variables on Kp were ranked. In addition, it was found that, in the addressed case, cutting conditions for maximum tool life actually increase Kp.

Detoxificación enzimática de cianuro mediante el uso de ina dehidratasa parcialmente purificada de la cepa Serratia marcescens AQ07

The partially purified enzyme of indigenously isolated Serratia marcescensstrain AQ07 was utilised to develop the best form of cyanide detoxification method that is eco-friendly and cost effective. The present study evaluates the feasibility of the enzyme to degrade high cyanide concentrations and the possible metabolic pathways involved, for which the protein concentration and cyanide detoxification activity were quantified. Bacterial cells grown in cyanide incorporated medium were disrupted by sonication and the resultant cell free extract were tested for metabolic pathway. The cell free extract was precipitated by ammonium sulphate precipitation and partially purified by ion exchange chromatography using DEAE cellulose. The maximum enzyme activity achieved was 2125 µM/min. The partially purified enzyme was found to be able to detoxify 82% of 2 mM KCN in 10 min of incubation and cyanide degradation (or depletion) rate showing a linear increase with increasing enzyme concentration. The effective accruing of ammonia as metabolite illustrated that the detoxification was ensued via the function of cyanide dihydratase. Additional confirmation through SDS-Page showed that the molecular weight of enzyme was assessed to be ~38 kDa, which is tandem with the reported cyanide dihydratases. Hence, the use of enzyme as a substitute to live bacterial cells in detoxification of cyanide illustrates various advantages such as the capacity to withstand and detoxify higher cyanide concentration and total reduction in the total cost of process since nutrient provision is immaterial.

Model Economic Production Quantity dengan Rework Process dan Batasan Gudang

Rework products and warehouse capacity are common problems experienced by companies in the production process. Several Economic Production Quantity (EPQ) models were developed to minimize the costs of purchasing raw materials. This study aims to develop an Economic Production Quantity (EPQ) model with rework processes and warehouse constraints, assuming that the product is not perfect and can rework. The proposed model considers several cost components, including setup, holding, production, rework, and warehouse. The two proposed models are EPQ models with reworks and warehouse costs, and EPQ models with reworks and warehouse constraints. Based on several tests conducted, it obtains that the increase in the value of the maximum inventory amount did not have an impact on the production costs and the cost of the rework process. Based on several numerical experiments, the total cost of the rework process and production costs do not change to the maximum inventory value.

Techno-economic and environmental approaches of Cd2+ adsorption by olive leaves (Olea europaea L.) waste

In this study, the techno-economic approach of olive leaves (Olea europaea L.) wastes for the removal of Cd2+ from aqueous solutions was demonstrated. The adsorption process was illustrated regarding batch experiments and scanning electron microscopy, energy dispersive X-ray, and Fourier-transform infrared characterization. The optimum pH and contact time were 6.6 and 123 min, respectively, giving Cd2+ removal efficiencies of 94.9% at Co = 50 mg/L and 81.5% at Co = 100 mg/L. The monolayer adsorption capacity of the Langmuir isotherm model was 32.6 mg/g (R2 = 0.97). The adsorption mechanisms might be related to (a) ion exchange with cations (e.g., K+, Na+, and Ca2+), (b) formation of cadmium chloride complexes, (c) interaction with oxygen-containing functional groups, (d) physical agglomeration in the pore surface, and (e) precipitation interaction using inorganic minerals (i.e., carbonates, phosphates, and silicates). The total cost of the adsorption process for the treatment of ions-containing wastewater was 0.038 $USD/m3. Assuming a benefit-cost of tertiary treated water as 0.044 $USD/m3, the adsorption system could attain a payback period of 5.7 years. This period was shorter than the lifetime of the capital investment (i.e., 10 years), and hence, the project would be economically feasible for an application.

Continuous synthesis of high purity KNO3 through electrodialysis metathesis

The traditional metathesis (double replacement) method for preparing the chlorine-free fertilizers has its shortcomings, such as high energy consumption and limited conversion degree. Here, the environmental-friendly and economical electrodialysis metathesis (EDM) process was developed to synthesize the potassium nitrate of high purity continuously. The experiments were carried out by using an EDM membrane module of 200 cm2 effective membrane area with 5 repeating units. Effects of operating parameters, current density, initial KNO3 concentration and water flow rate of the KNO3 tank, on EDM performance (energy consumption and current efficiency) and KNO3 quality were investigated. Results showed that the lowest energy consumption (0.165 kWh/kg KNO3) can be attained, while the current efficiency and K2O content in the final product can be high to 94.10% and 44.61 wt%, respectively. After a preliminary and simple purification, the products can meet the requirements of the Chinese national standard GB/T20784-2006. What is more, results of the economic evaluation showed that the total process cost of the continuous EDM system is 0.119 $/kg KNO3, which is lower than that of batch mode (0.160 $/kg KNO3). In addition, the production cost of KNO3 is about 622.10 $/t KNO3, which is lower than the commercial product price (705 $/t KNO3). To sum up, the above results suggest that the continuous EDM process for generating KNO3 of high purity is economically feasible and has great potential to be industrialized.

Techno-economic analysis of acetone-butanol-ethanol distillation sequences feeding the biphasic condensate after in situ gas stripping separation

Distillation processes for separation of biphasic ABE solution from in situ gas stripping were developed. The distillation sequences were investigated and optimized. Results proved the energy requirement of distillation was effectively reduced when feeding the biphasic ABE mixture. After techno-economic analysis, a superior scenario that started with a decanter followed with side-by-side sequences for separation acetone and ethanol was selected. Compared with the conventional processes that detractively concentrate the biphasic ABE mixture, energy requirement and total annual cost (TAC) of the novel distillation process were decreased by 25.8% and 17.4%, respectively. $ 4102.98 K per year of TAC was estimated in a case with a capacity of 30 K tons of butanol per year.

Treatment of printing ink wastewater using electrocoagulation

The present study investigates the treatment of real printing ink wastewater by using the electrocoagulation (EC) process. Effects of initial chemical oxygen demand (COD) concentrations, electrode materials and current densities were examined to determine the maximum COD and color removal from the wastewater. In parallel, raw and treated printing ink wastewater toxic potential was further estimated via the application of toxicity tests using the freshwater crustacean Thamnocephalus platyurus for assessing EC process efficiency. According to the results, it was observed that the EC is efficient under most of the operating conditions used, as COD and color removal ranged between 72.03 to 85.81% and 98.7–100%, respectively. The total cost of the EC process, considering the treatment time, applied current, applied voltage and the total anode electrode mass consumption was also estimated. The Fe electrode proved to be of lower cost than the Al electrode, however the use of Al electrode produced better decolorization results in the solutions. Moreover, toxicity tests currently performed with the use of larvae of the fairy shrimp Thamnocephalus platyurus revealed a substantial decrease in the toxic potential of printing ink wastewater, thus indicating the efficiency of the proposed EC process.

Study of equilibrium and kinetic adsorption of rhodamine B onto purified bentonite clays

Abstract Currently, the removal of contaminants such as wastewater dye has become an essential task. In view of this, improving the performance of the adsorbents in order to improve the adsorption technique and reduce the total cost of the adsorption process is of great interest to the industrial sector. This study investigated the adsorption process of natural and purified bentonite clay adsorbents, using rhodamine B in an aqueous media. Rhodamine B is very toxic to aquatic organisms and may cause long-term adverse effects in the aquatic environment. These clays were used both in the natural form and after purification by centrifuge. All adsorbents were characterized. The kinetics and equilibrium isotherms were studied. In equilibrium, the Freundlich isotherm model was the best fit to the experimental data. In kinetics study, the data were best fit by the pseudo-second order model. The purified clays efficiently removed the rhodamine B.

PENETAPAN HARGA JUAL PRODUK (UMKM) DI SUKABUMI DENGAN MENGGUNAKAN METODE COST BASED PRICING

Abstrack :The purpose of this research paper is to implement a method of cost-based pricing on CV. Midi Sukabumi in determining the selling price Lidi Osyin Noodle. The analysis technique that used is descriptive quantitative approach analysis technique used to analyze numbers using formulas and make descriptions systematically . the result of this research is determining the selling price on CV. Midi Sukabumi by using cost based pricing method are of two calculations , is cost plus pricing used to calculate the total cost of production and non-production process. And the second calculation is the calculation of mark up pricing used for reseller agents by adding a desired mark up on the purchase price of unity. Key Words : Full costing, cost based pricing, cost plus pricing, and mark up pricing

A simplified method of preparation of mammalian intestine samples for scanning electron microscopy

Due to strong tissue hydration and complex architecture of the mucous membrane, appropriate preparation of inhomogeneous gastrointestinal tissues, especially from the intestine, for scanning electron microscopy is still a challenge and requires constant improvement of preparation techniques. In this article, we describe a simplified method of preparation of small intestinal mucosa tissues for observations in a scanning electron microscope. We emphasized the most important points in the preparation process that, when ignored, may result in formation of numerous artifacts and the inability to analyze the samples reliably. The developed technique facilitates proper animal tissue sampling in the field conditions, reducing the time of tissue collection and sample preparation as well as the total process costs. The fixative of choice, that is, buffered formalin, fixes, and stiffens the processed tissues properly, which is especially important in preservation of long, highly hydrated intestinal villi without shrinkage artifacts. The method described has been successfully used in comparative studies of the development of small intestines in mammals (pigs, mice, rats), reptiles, and birds (hens).

Design, Optimization, and Retrofit of the Formic Acid Process II: Reactive Distillation and Reactive Dividing-Wall Column Retrofits

Formic acid (FA) is an important chemical with many applications in the industry. Nevertheless, its manufacturing process has not received much attention in the open literature. In Part I of this series (da Cunha et al., Ind. Eng. Chem. Res. 2018, 57, 9554–9570), FA process was simulated and optimized for the production of 98 wt % FA. Total annual cost (TAC) of the optimal base case process was 0.686 USD/kg. This process was then retrofitted via integration of two distillation columns into a dividing-wall column (DWC), but such retrofit was not profitable. Here, in Part II, FA process retrofit via reactive distillation (RD) and reactive dividing-wall column (RDWC) are investigated in detail. Results show that RD retrofit is not attractive as it increases TAC of the process. However, retrofit via RDWC is profitable, resulting in a thermal energy savings of 20.4% and a TAC savings of 0.020–0.042 USD/kg (by 3%–6%).

Synthesis of chitosan-cellulase nanohybrid and immobilization on alginate beads for hydrolysis of ionic liquid pretreated sugarcane bagasse

Abstract Sugarcane bagasse, has been studied as lignocellulosic feedstock to derive bioethanol; a major step towards the invention of green and sustainable energy. Major cost of the whole process lies in the enzymatic digestion of bagasse, since cost of cellulase enzyme is too high. Thus recovery and reuse of cellulase can reduce the total process cost. The perspective of cellulase recycling after hydrolysis of ionic liquid pretreated sugarcane bagasse was studied by synthesizing chitosan-cellulase nanohybrid and immobilizing the nanohybrid in alginate beads. SEM and Particle size analysis confirmed the formation of variable size of nanoparticles and zeta potential denoted the tendency to form agglomerate. The performance of immobilized nanohybrid was optimized by varying different operating parameters such as pH (3–7) and temperature (30–60 °C). Immobilized nanohybrid showed higher immobilization yield and stability as compared to immobilized cellulase at the optimum condition. The maximum reducing sugar concentration of 38.87 gm/lit was achieved when immobilized nanohybrid was loaded at 20 FPU/gm of pretreated bagasse. Hydrolysate thus obtained was fermented and 0.38 g/g ethanol yield was obtained. Immobilized nanohybrid was successfully recycled up to five times which made the hydrolysis step eco-friendly and economically feasible. The contribution of the investigation leads towards the development of energy efficient enzyme recycling scheme.

An integrated cost and worker fatigue evaluation model of a packaging process

This paper proposes a model for managing a packaging process of small products at a production line. The aim of the paper is to determine the optimal size of a box the products are stored in considering both financial (in terms of cost) and ergonomic (in terms of worker fatigue) aspects. The paper first develops a biomechanical model to estimate the expected fatigue-recovery parameters associated with the packaging process. Secondly, it proposes an optimization model that minimizes the total relevant cost of the packaging process consisting of the cost of packaging material and the cost of working time, which includes the time required for packing items, setting up and handling boxes, transporting boxes to the shipping area, and idle time cost. Thirdly, the fatigue-recovery approach is integrated into the optimization model to determine the optimal box size from a given set of alternative boxes as well as the work schedule that minimize the total relevant cost while satisfying the upper bound on the estimated total (accumulated) fatigue level. The developed model is then analysed in a numerical experiment inspired by a case observed in industry. The results of the numerical analysis show that smaller box sizes are less sensitive to changes in the maximum permitted fatigue level and that they lead to lower total relevant cost for low wage cost. Larger boxes, in turn, are recommended for higher wage cost. The maximum permitted fatigue level and the box sizes also influence the fatigue range experienced by the worker as well as the share of productive time the worker spends on the job.

Mineralization of quinoline in aqueous solution by microwave-assisted catalytic wet peroxide oxidation system: process optimization, products analysis and degradation route research.

The experimental design methodology was used to optimize the experimental parameters of quinoline mineralization by microwave-enhanced catalytic wet peroxide oxidation (CWPO). Initial pH value, temperature, H2O2 dosage, and microwave power were selected as independent variables. The mineralization efficiency approached 83.82% under the optimized conditions: initial pH 6.00, temperature 60 °C, H2O2 dosage 0.09 mol/L, and microwave power 565.10 W. Regression analysis with an R2 value of 0.9867 showed a good agreement between the experimental results and the predicted values. Furthermore, based on the detection and identification of products by gas chromatography mass spectrometry, the oxidation degradation pathways of quinoline were proposed. The energy balance and costs analysis indicated that the total cost of the microwave-enhanced CWPO process for wastewater treatment was 40.60 yuan/m3.

Bipolar membrane electrodialysis for the recycling of ammonium chloride wastewater: Membrane selection and process optimization

Here, bipolar membrane electrodialysis (BMED) with BP-A configuration is employed to convert ammonium chloride wastewater into hydrochloric acid and ammonium hydroxide to overcome the shortcomings of conventional treatment methods First, different commercial anion exchange membranes (TWEDA2, AMV, JAM-II and CJMA-2) and bipolar membranes (BP-1, BPM-I and FBM) were used to conduct the BMED process. Results show that AMV and BPM-I are regarded as the optimum membranes in consideration of process performance, energy consumption and process cost comprehensively. Second, BMED process is optimized by changing current density, initial NH4Cl concentration and initial volume ratio of acid solution and NH4Cl solution. Results indicate that as current density increases from 70 to 90mA/cm2, energy consumption and generated HCl concentration can increase from 1.51 to 2.83 kWh/kg HCl and 2.45 to 2.84mol/L respectively, and the total process cost of 70mA/cm2 is the highest (0.80$/kg HCl); meanwhile, increasing initial NH4Cl concentration can increase energy consumption, generated acid concentration and total process cost; in addition, with the increment of initial volume ratio from 0.5 to 1.0, energy consumption varies between 1.46 and 1.62 kWh/kg HCl and generated acid concentration improves from 1.95 to 2.71mol/L, while total process cost decreases from 0.63 to 0.42$/kg HCl. In short, based on these results, the optimum operation condition is that current density is 80mA/cm2, initial NH4Cl concentration is 1mol/L and initial volume ratio of acid solution and NH4Cl solution is 0.67–0.83.

A framework for the identification of promising bio‐based chemicals

Recent progress in metabolic engineering and synthetic biology enables the use of microorganisms for the production of chemicals-"bio-based chemicals." However, it is still unclear which chemicals have the highest economic prospect. To this end, we develop a framework for the identification of such promising ones. Specifically, we first develop a genome-scale constraint-based metabolic modeling approach, which is used to identify a candidate pool of 209 chemicals (together with the estimated yield, productivity, and residence time for each) from the intersection of the high-production-volume chemicals and the KEGG and MetaCyc databases. Second, we design three screening criteria based on a chemical's profit margin, market volume, and market size. The total process cost, including the downstream separation cost, is systematically incorporated into the evaluation. Third, given the three aforementioned criteria, we identify 32 products as economically promising if the maximum yields can be achieved, and 22 products if the maximum productivities can be achieved. The breakeven titer that renders zero profit margin for each product is also presented. Comparisons between extracellular and intracellular production, as well as Escherichia coli and Saccharomyces cerevisiae systems are also discussed. The proposed framework provides important guidance for future studies in the production of bio-based chemicals. It is also flexible in that the databases, yield estimations, and criteria can be modified to customize the screening.

Design, Optimization, and Retrofit of the Formic Acid Process I: Base Case Design and Dividing-Wall Column Retrofit

Formic acid (FA) is an important chemical with many applications in the industry. Despite this, the FA process has not received much attention in the open literature. In this work, FA process design and optimization are performed for the production of 98 wt % FA. Total annual cost (TAC) of the optimal base case process is 0.686 USD/kg. In addition, a recently developed methodology for process retrofit is applied, and retrofitting two distillation columns to a dividing-wall column (DWC) is investigated in detail. Results show that DWC retrofit is not attractive as it increases TAC of the process. The reasons for the increase in TAC are discussed. However, the FA process with DWC is attractive for a new plant, with lower capital and operating costs compared to the optimized base case process with conventional distillation columns.

Conventional and advanced exergoeconomic assessments of a new air separation unit integrated with a carbon dioxide electrical power cycle and a liquefied natural gas regasification unit

In this study for the first time a new air separation unit with a carbon dioxide power cycle based on cold energy recovery of liquefied natural gas is investigated by conventional and advanced exergoeconomic analyses. With conventional exergy analysis, the source of irreversibility in the process can be determined, while with advanced exergy analysis, the real potential can be determined for improving the process operating performance as well as component interactions. The exergy destruction rate and total operating cost are divided into two catagories which are sub-parts of each other: endogenous/exogenous and unavoidable/avoidable. The exergy and exergoeconomic analyses indicate that the total process cost can be decreased by improving the performance and efficiencies of compressors and heat exchangers. This is because these types of process components have the largest and smallest exergoeconomic factor values, respectively. Results of the advanced exergy and exergoeconomic analyses demonstrate that, when considering the avoidable endogenous investment cost rate, compressors have priorities for modification. Also, based on the avoidable endogenous cost rate, one of the heat exchangers should be modified at first. The exergy destruction and investment cost rates in most of the process components are endogenous. A sensitivity analysis is performed to evaluate the effects of economic and thermodynamic parameters on the advanced exergoeconomic parameters. It is concluded that the configuration of the process components has a significant impact on their costs.

Investigating the impact of sustainability in the production of aeronautical subscale components

The aim of this paper is to investigate the impact of sustainability aspects in the production of aeronautical subscale components by comparing the traditional riveted versus the innovative Laser Beam Welding (LBW) process in industrial conditions. We adopt a quantitative assessment methodology for both processes, by taking into account a series of manufacturing scenarios with six multi-dimensional aeronautical subscale components in different annual production rates (mass production). The results reveal that the exploitation of the LBW technology can provide weight savings up to 28%, by exploiting lower density AlCuLi alloys, while the time savings during the manufacturing process can be up to 67%. Furthermore, the total manufacturing cost of the LBW process can be reduced up to 40% for the case of long structures, when compared to the corresponding riveted structures. In terms of environmental friendliness, the LBW process results to increased CO2e emissions by 124% during the manufacturing process when compared to the riveting process. However, this difference is lower than 60% when longer structures with smaller count of stringers are used. Finally, despite the high carbon footprint emission during the manufacturing phase, when the life cycle of aircrafts is assessed, the LBW joining process can contribute to lighter components, resulting to less weighted aircrafts whose engines consume less fuel, contributing in that way to energy and GHG emissions reductions.

Simulation and optimization of different pressure thermally coupled distillation for separating a close-boiling mixture of n-butanol and iso-butanol

Substantial quantities of energy are required in conventional distillation columns applied in high-purity separation of close-boiling mixtures. To achieve energy saving of distillation, a novel different pressure thermally coupled distillation (DPTCD) was proposed for separating the close-boiling mixture of n-butanol and iso-butanol. Both this intensified energy integration technique and two other processes, namely conventional distillation (CD) and vapor recompression column (VRC), were simulated in process simulator Aspen Plus. The optimization was carried out to determine the optimal values of design and operating variables on the basis of minimizing energy consumption. Subsequently, the energy saving and economic efficiency of the DPTCD scheme were evaluated through the comparison with the other two processes. The results showed that, compared to the CD and VRC processes, the energy consumption of DPTCD process was decreased by 65.21 and 15.79%, respectively, and the total annual cost (TAC) of DPTCD process can be reduced by 33.75 and 10.46%. It demonstrated that DPTCD scheme was the most promising alternative to reduce the total energy consumption and TAC with high purity (99.1 wt%) n-butanol and iso-butanol products among these separation processes.