Steam Stripping Process Research Articles

Steam Stripping for Recovery of Ammonia from Wastewater Using a High-Gravity Rotating Packed Bed

Steam stripping of ammonia from ammonia-rich wastewater (5000–20,000 mg/L) was conducted in a continuous-flow rotating packed bed (RPB) at a pH of 11. This study aimed to elucidate the influence of key operational parameters, including the steam-to-liquid ratio, rotational speed (ω), initial ammonia concentration, steam inlet temperature (TSi), and liquid inlet temperature (TLi), on critical performance metrics such as the ammonia removal efficiency (ARE), the volumetric liquid mass transfer coefficient (KLa), and the concentration of the recovered ammonia solution (CR). The findings revealed that a CR of 22.88 wt.% was achieved under the optimal conditions of a steam-to-liquid ratio of 0.175 kg/kg, an initial concentration of 20,000 mg/L, a TSi of 120 °C, and a TLi of 70 °C. Key experimental factors, including the initial ammonia concentration, TSi, and TLi, significantly impacted the achievement of higher ARE and CR values. The KLa values exhibited a decrease with the increase in the steam-to-liquid ratio, while they increased with ω. However, the KLa remained relatively consistent with ω values within the range of 600 to 1200 rpm. In comparison with prior studies, steam stripping of ammonia exhibits a higher ARE than air stripping with RPB and a higher CR than conventional stripping methods. Moreover, RPB requires a smaller size to achieve equivalent ARE compared to conventional stripping apparatuses. Thus, the steam stripping process with RPB equipment emerges as a suitable method for ammonia recovery from ammonia-rich wastewater.

Anaerobic Digestion of Kraft Pulp Mill Foul Condensate Under Thermophilic and Mesophilic Conditions

Foul condensate produced during the chemical recovery step of the kraft pulping process is a methanol-rich wastewater stream commonly treated through a steam-stripping process to extract volatile components before their combustion. Applying anaerobic digestion to treat this wastewater stream presents an opportunity to recover the inherent renewable bioenergy without the associated steam utilization and improve the overall energy balance of the mill. In this study, a comparison of the performance and microbiology of anaerobic digesters treating foul condensate under thermophilic and mesophilic conditions was performed. In terms of performance, both digesters performed similarly with an optimal organic loading rate and hydraulic retention time of 4 kg chemical oxygen demand (COD/[m3·day]) and 1.5 days, respectively, which produced similar methane yields of ∼200 L CH4 per kg COD loaded resulting in a methane productivity of ∼0.75 L/(L·day). The anaerobic digesters removed 95–99% of methanol-associated COD but only 16–25% of non-methanol-associated COD in the feedstock. Microbial community analysis showed that under mesophilic conditions, methylotrophic methanogenesis was the principal mechanism for methanol removal while a hydrogenotrophic methanogenesis pathway was dominant under thermophilic and favored under higher sulfur loading conditions.

Designing of spiral wound nanofiltration multistage process for oil concentration and solvent recovery from soybean oil/n-hexane miscella

The present work demonstrates the potential of oil/n-hexane miscella separation from a local factory via a hybrid nanofiltration-evaporation process. In the membrane separation, solvent resistance nanofiltration (SRNF) membranes lab-made of polyvinylidene fluoride (PVDF) as support, poly-dimethylsiloxane (SI) or cellulose acetate (CA) as coating materials and a commercial composite membrane were used. To perform this study, a representative spiral-wound (SW) module made-up with the membranes previously mentioned was employed. For miscella mass transfer through the SW module, a plug-cross-mixing flow (PCMF) model was used. From experimental miscella permselectivity data at T = 30 °C and Δp = 20 bar, an analytical final expression of mass balance was obtained which correlated the retentate oil concentration with the membrane area. The multistage process of such membranes was integrated by a number of single-stage in series. In the multistage membrane performance evaluation, several restrictions were imposed on the model considering the operational conditions of the local factory that uses an evaporation and steam stripping process. Seven stage (total membrane area 702 m2) using PVDF-10% SI membrane gave the best oil/n-hexane separation effectiveness. From this, a hybrid SRNF-evaporation process was proposed in which the selected membrane multistage process replaced the first and the second evaporators. The permeate stream rich in n-hexane (90.5 w%) was fed to the section of the expeller in which the oil was depleted, and the retentate stream enriched in oil (86.7 w%) was pumped to the third-stage evaporator and strippers, where the oil was concentrated to >99 w%. The overall energy demand was significantly reduced (≈50%) and there was around 60% less consumption of cooling water and steam by the SRNF-assisted processes in comparison with the conventional factory evaporation process.

Deacidification of Palm Oil Using Betaine Monohydrate-Carboxylic Acid Deep Eutectic Solvents: Combined Extraction and Simple Solvent Recovery

Steam stripping is commonly used to remove free fatty acids from crude palm oil. An alternative deacidification method, solvent extraction performed at a much lower temperature, would preserve the natural antioxidants in the refined palm oil. In this work, palmitic acid was extracted using betaine monohydrate-propionic acid and betaine monohydrate-acetic acid deep eutectic solvents (DESs). The effect of temperature (40 °C to 80 °C), mass ratio of palm oil to solvent (2:1 to 1:2), and palmitic acid content in the palm oil feed (2% to 8% mass) on the distribution coefficient values of palmitic acid (0.44–0.93) was investigated. For the first time, a facile recovery of DESs could be accomplished by a cooling process where up to 98% of the palmitic acid separates as solid. A solvent extraction process for palm oil deacidification, employing a DES with a distribution coefficient value much higher than unity, will provide advantages over the steam stripping process.

Process Simulations of the Direct Non-Aqueous Gas Stripping Process for CO2 Desorption

The integration of the direct steam stripping (DSS) process with organic working fluid promises a significant reduction in the energy penalty for the CO2 capture process. This work investigates the mechanisms of the mass transfer enhancement in direct pentane stripping (DPS) process using simulation methods. Through regressing the molecule-molecule interaction parameters, a quaternary system thermodynamic model (QSTM) is developed to successfully predict the vapor-liquid equilibrium of Amine/CO2/Pentane/H2O system. Three typical solvents, monoethanolamine (MEA), methyldiethanolamine (MDEA), and 2-amino-2-methyl-1-propanol (AMP) are studied in this work. The DPS process using 30 wt.% MEA, 30 wt.%MDEA, and 30 wt.% AMP exhibits the solvent regeneration energy of 2.55, 2.65, and 2.01 GJ/tCO2 under the optimal conditions, which is 34%, 32%, and 48% lower than of the conventional MEA-based process. DPS using MDEA shows an energy advantage over the other two solvents because of the high CO2 equilibrium partial p...

Process Simulations of CO2 Desorption in the Interaction between the Novel Direct Steam Stripping Process and Solvents

Intensive energy consumption is one of the major challenges for large-scale implementation of amine-based CO2 chemical absorption processes. The study of diverse typical solvents in a novel process can effectively exploit the potential of energy saving to the utmost. This work focuses on the optimization of a novel direct steam stripping process using three typical solvents, monoethanolamine (MEA), 2-amino-2-methyl-1-propanol (AMP), and piperazine (PZ). A rate-based model was established to investigate the regeneration process. The direct steam stripping process exhibits 20–30% reduction in energy penalty for different solvents. Detailed information on the concentration and pressure profiles along the stripping column was presented in the direct steam stripping process. There is a strong flash process at the top of the column, which results in an enormous reduction of the latent heat. Therefore, using MEA as the absorbent shows the best performance on reducing energy penalty as a result of its best proper...

Conversion of Cellulose to 5-Hydroxymethylfurfural using Inorganic Acidic Catalysts in the Presence of Pressurized Water Steam

Traditionally, 5-hydroxymethylfurfural (HMF) is produced by using a water-organic solvent medium, which inevitably increases production costs and adds subsequent separation processes. To minimize cost and/or toxic organic solvent usage, this study presents an effective pathway for producing HMF from cellulose. The process uses a fixed bed reactor with a steam stripping process in which the cellulose is converted into HMF and other products in the presence of acidic inorganic salts. In the process, the cellulose was hydrolyzed to glucose, which was followed by isomerization to fructose and fructose dehydration into HMF. The produced HMF was easily vaporized into the gas phase, which avoided its conversion into undesired byproducts. An acceptable HMF yield of 28.2 mol% was obtained using KH2PO4 as the catalyst at 270 °C. This technology could be used to obtain both HMF and furfural (FF) from different lignocellulosic biomasses. This stripping technology has advantages such as the lack of organic solvents, showing an alternative and green HMF and/or FF production from lignocellulosic biomass.

Experimental Study on the Novel Direct Steam Stripping Process for Postcombustion CO2 Capture

High energy consumption is a crucial issue for the regeneration of solvent for postcombustion CO2 capture by chemical absorption. Primary modeling results show the potential to reduce the energy consumption through a novel solvent regeneration process by direct steam stripping. This work is an extension of our previous exploration and aims to validate the direct steam stripping process by experimental studies on a lab-scale stripping platform. We investigated the direct steam stripping and the conventional stripping mode in terms of energy consumption and steam condensation. The results showed, for the direct steam stripping mode, the optimum energy consumption at 1 atm was 2.98 MJ/kg CO2, 23.2% lower than that of the conventional stripping mode. Higher solvent feeding temperature and carrier steam superheating temperature were beneficial to reduce steam condensation in the column. We found 96–99.5 °C feeding solvent temperature was suitable considering both the energy consumption and steam condensation. ...

Novel Solvent Regeneration Process through Direct Steam Stripping

Abstract High energy consumption during solvent regeneration is a crucial issue for the CO 2 post-combustion capture by chemical absorption. In order to save the latent heat in the regeneration process, it is possible to regenerate the solvent through direct steam stripping. This work aims to validate the direct steam stripping process by experimental study on a lab-scale stripper column. The novel direct steam stripping process showed potential to reduce regeneration energy in comparison to the conventional regeneration process. The minimum energy consumption of direct steam stripping mode was 2.98 MJ/kg CO 2 , 23% lower than that of the conventional regeneration mode which is 3.88 MJ/kg CO 2 . Water balance was also investigated. Based on the experimental results, a high feeding solvent temperature close to solvent boiling point and superheated carrier steam was preferred for direct steam stripping process.

Production of furfural from pentosan-rich biomass: Analysis of process parameters during simultaneous furfural stripping

Among the furan-based compounds, furfural (FUR) shows interesting properties as building-block or industrial solvent. It is produced from pentosan-rich biomass via xylose cyclodehydration. The current FUR production makes use of homogeneous catalysts and excessive amounts of steam. The development of greener furfural production and separation techniques implies the use of heterogeneous catalysts and innovative separation processes. This work deals with the conversion of corncobs as xylose source to be dehydrated to furfural. The results reveal differences between the use of direct corncob hydrolysis and dehydration to furfural and the prehydrolysis and dehydration procedures. Moreover, this work focuses on an economical analysis of the main process parameters during N2-stripping and its economical comparison to the current steam-stripping process. The results show a considerable reduction of the annual utility costs due to use of recyclable nitrogen and the reduction of the furfural purification stages.

Determination and Modeling of Solubility for CaSO4·2H2O–NH4+–Cl––SO42––NO3––H2O System

The solubility of gypsum (CaSO4·2H2O) in ammonium solutions plays a significant role to prevent gypsum scaling on the heater and tower in the treatment of ammonium-N wastewater bearing sulfate ions by the steam stripping process. In this work solubilities of calcium sulfate dihydrate in NH4Cl, NH4NO3, and mixed NH4Cl and (NH4)2SO4 solutions up to 343.15 K were measured using the classic isothermal dissolution method. The investigated concentration (at ambient temperature) is up to 1.50 mol·dm–3 for both NH4Cl and NH4NO3. The solubility of CaSO4·2H2O was found to increase sharply with either NH4Cl or NH4NO3 concentration, whereas the temperature has a limited effect. The XRD analysis of equilibrated solids for these systems shows that CaSO4·2H2O is stable in all cases over the temperature range (298.15 to 343.15) K. The electrolyte nonrandom two-liquid (the electrolyte NRTL) model embedded in AspenPlus was applied to model the solubility of CaSO4·2H2O in the above systems. The newly obtained model parameters were used to well estimate the solubility of CaSO4·2H2O in all cases with a relative deviation of 1.52 %.

Recovery of Lemon Essential Oil, Lemon Wax, and Diatomaceous Earth from the Filter Cake of the Lemon Essential Oil Dewaxing Process at Pilot-Plant Scale

A pilot-plant scale unit suitable for recovery of lemon essential oil, lemon wax, and diatomaceous earth that exists in the waste filter cake arising from the dewaxing process of the cold-pressed lemon essential oil has been developed for batch operation, using a steam stripping process. It includes steam-distillation of the essential oil contained in the filter cake followed by its liquid−liquid separation from water, cooling and decantation of the nonvolatile residue that remains inside the stripper, and manual separation of lemon wax and diatomaceous earth. Mass and energy balances of the process were also made, which allow for the calculation of the time to exhaust the oil and the consumed vapor required to extract one kilogram of essential oil. The experimental results show that this process is suitable for the separation of these “three components” of the filter cake at pilot-plant scale, minimizing the environment contamination.

EXTRAÇÃO DO ÓLEO E RESINAS DE GENGIBRE ENCONTRADO NO LITORAL PARANAENSE (Zingiber officinale Roscoe)

Este trabalho descreve os processos utilizados para a obtenção do óleo e da resina de gengibre, extraídos do seu rizoma “in natura” e processado. Os ensaios foram efetuados com rizoma “in natura”, colhido, lavado e mantido sob refrigeração até o momento do uso e seco em estufa de ar forçado até redução da umidade a 10% (m/m) e finalmente estocado sob refrigeração. Os processos de obtenção do óleo e resinas envolveram a extração com solventes orgânicos, além de extração de óleos voláteis por arraste de vapor. Os resultados mostraram que a melhor qualidade do óleo é obtida pelo processo de arraste de vapor, com tempo de extração de 2 horas, e que a maior quantidade de resina é obtida utilizando a propanona como solvente e tempo de extração de 3 horas.

Purification of Polymers from Solvents by Steam or Gas Stripping

A mathematical model is developed of the steam-stripping process in polymer−solvent−water systems under agitation, describing it in terms of the current theories in the field of polymer−solvent sol...

A new regenerable process for the recovery of SO2

AbstractIncreasing demand for regenerable processes with SO2 recovery is to be expected. Advantages and limitations of the earlier developed citrate and adipate absorption/ steam stripping process are compared with those of the Wellman‐Lord (sulphite) process. On the basis of comprehensive laboratory studies, a new process is proposed which supplements the citrate and adipate process. In this new process, the absorbent is a concentrated sodium phosphate buffer and the loaded buffer is regenerated by evaporation. The main buffer component is Na2HPO4, but NaH2PO4 is added in order to obtain a more complete stripping of SO2 during regeneration. The new process promises excellent absorption properties for SO2 with extremely low oxidation losses, regeneration with few incrustation problems and appreciable energy savings.

The spectroscopy of the sulphonated indigotins

Among the furan-based compounds, furfural (FUR) shows interesting properties as building-block or industrial solvent. It is produced from pentosan-rich biomass via xylose cyclodehydration. The current FUR production makes use of homogeneous catalysts and excessive amounts of steam. The development of greener furfural production and separation techniques implies the use of heterogeneous catalysts and innovative separation processes. This work deals with the conversion of corncobs as xylose source to be dehydrated to furfural. The results reveal differences between the use of direct corncob hydrolysis and dehydration to furfural and the prehydrolysis and dehydration procedures. Moreover, this work focuses on an economical analysis of the main process parameters during N2-stripping and its economical comparison to the current steam-stripping process. The results show a considerable reduction of the annual utility costs due to use of recyclable nitrogen and the reduction of the furfural purification stages.