Hydrolysis Reactor Research Articles

Investigation of a submerged membrane reactor for continuous biomass hydrolysis

Enzymatic hydrolysis of cellulose is one of the most costly steps in the bioconversion of lignocellulosic biomass. Use of a submerged membrane reactor has been investigated for continuous enzymatic hydrolysis of cellulose thus allowing for greater use of the enzyme compared to a batch process. The submerged 0.65μm polyethersulfone microfiltration membrane avoids the need to pump a cellulose slurry through an external loop. Permeate containing glucose is withdrawn at pressures slightly below atmospheric pressure. The membrane rejects cellulose particles and cellulase enzyme bound to cellulose. Here proof-of-concept experiments have been conducted using a modified, commercially available membrane filtration cell under low fluxes around 75L/(m2h). The operating flux is determined by the rate of glucose production. Maximizing the rate of glucose production involves optimizing mixing, reactor holding time, and the time the feed is held in the reactor prior to commencement of membrane filtration and continuous operation. Maximizing glucose production rates will require operating at low glucose concentration in order to minimize the adverse effects of product inhibition. Consequently practical submerged membrane systems will require a combined sugar concentration step in order to concentrate the product sugar stream prior to fermentation.

Spatial and temporal variability of odorous VOC in a food waste treatment plant using hydrothermal hydrolysis and aerobic fermentation technology

Offensive odorant emissions from a food waste (FW) treatment plant that uses hydrothermal hydrolysis and aerobic fermentation technology were studied for 1 month through in situ monitoring and laboratory testing. Results showed that the emission flux (7000 μg kg−1FW h−1) of total volatile organic compounds and concentrations of most volatile organic compounds (VOCs) were highest at the discharge outlet of the hydrothermal hydrolysis reactor. Furthermore, VOC composition analysis showed that the concentrations of most hydrocarbons detected during the sorting/crushing process were higher than those in the aerobic fermentation process, but more oxygenated organic compounds and pinenes were released in the aerobic treatment process. The analysis of VOC temporal characteristics via t test indicated that even with various FW loads during the day and night, most VOC concentrations sampled in the storing room were not significantly different. However, great variances among most VOC concentrations were observed during the sorting/crushing process and at the hydrothermal hydrolysis reactor. The annoyance degrees of offensive gases were also determined via analysis of odor indices. The results suggested that sulfocompounds mainly dominated in terms of high odor activate values during the sorting/crushing process, and the fractional content of oxygenated organic compounds increased in the aerobic treatment processes.

Progress in thermochemical hydrogen production with the copper–chlorine cycle

Recent advances are reported by an international team on research and development of the copper chlorine (Cu–Cl) cycle for thermochemical hydrogen production. New experimental and numerical results are given for several processes of the cycle. Experimental results for CuCl/HCl electrolysis and integration of unit operations in the Cu–Cl cycle are presented. A new solubility model for the CuCl–CuCl2–HCl–H2O quaternary system is presented, which optimizes the cupric chloride selective precipitation prior to the hydrolysis reactor. Also, recent progress on photo-electrochemical cell development for enhancement of the electrolysis process is reported along with its integration with a concentrated solar radiation system.

Energetic approach of biomass hydrolysis in supercritical water

Cellulose hydrolysis can be performed in supercritical water with a high selectivity of soluble sugars. The process produces high-pressure steam that can be integrated, from an energy point of view, with the whole biomass treating process. This work investigates the integration of biomass hydrolysis reactors with commercial combined heat and power (CHP) schemes, with special attention to reactor outlet streams. The innovation developed in this work allows adequate energy integration possibilities for heating and compression by using high temperature of the flue gases and direct shaft work from the turbine. The integration of biomass hydrolysis with a CHP process allows the selective conversion of biomass into sugars with low heat requirements. Integrating these two processes, the CHP scheme yield is enhanced around 10% by injecting water in the gas turbine. Furthermore, the hydrolysis reactor can be held at 400°C and 23MPa using only the gas turbine outlet streams.

Predicting Power for a Scaled‐up Non‐Newtonian Biomass Slurry

AbstractHigh‐solids biomass slurries exhibit non‐Newtonian behavior with a yield stress and require high power input for mixing. The goals were to determine the effect of scale and geometry on power number P0, and estimate the power for mixing a pretreated biomass slurry in a 3.8 million L hydrolysis reactor of conventional design. A lab‐scale computational fluid dynamics model was validated against experimental data and then scaled up. A pitched‐blade turbine and A310 hydrofoil were tested for various geometric arrangements. Flow was transitional; laminar and turbulence models resulted in equivalent P0 which increased with scale. The ratio of impeller diameter to tank diameter affected P0 for both impellers, but impeller clearance to tank diameter affected P0 only for the A310. At least 2 MW is required to operate at this scale.

Development of new heat exchanger network designs for a four-step Cu–Cl cycle for hydrogen production

The Aspen Plus process simulation package is used to evaluate the characteristics of the four-step Cu–Cl thermochemical water splitting cycle in terms of energy and exergy, to support the ultimate development of a pilot plant. Alternative designs for the heat exchanger network using Aspen Energy Analyzer are developed and studied for thermal management within the Cu–Cl cycle. The simulation results for the four-step Cu–Cl cycle illustrate that the steam-to-copper molar ratio can be reduced to 10 from an initial value of 16 by decreasing the pressure of the hydrolysis reactor. A thermodynamic model of the four-step Cu–Cl cycle is developed to determine its energy and exergy efficiencies. The energy and exergy efficiencies of the four-step Cu–Cl cycle are determined to be 55.4% and 66.0%, respectively.

Thermal conductivity characteristics of dewatered sewage sludge by thermal hydrolysis reaction

The purpose of this study is to quantify the thermal conductivity of sewage sludge related to reaction temperature for the optimal design of a thermal hydrolysis reactor. We continuously quantified the thermal conductivity of dewatered sludge related to the reaction temperature. As the reaction temperature increased, the dewatered sludge is thermally liquefied under high temperature and pressure by the thermal hydrolysis reaction. Therefore, the bound water in the sludge cells comes out as free water, which changes the dewatered sludge from a solid phase to slurry in a liquid phase. As a result, the thermal conductivity of the sludge was more than 2.64 times lower than that of the water at 20℃. However, above 200℃, it became 0.704 W/m•°C, which is about 4% higher than that of water. As a result, the change in physical properties due to thermal hydrolysis appears to be an important factor for heat transfer efficiency.ImplicationsThe thermal conductivity of dewatered sludge is an important factor the optimal design of a thermal hydrolysis reactor. The dewatered sludge is thermally liquefied under high temperature and pressure by the thermal hydrolysis reaction. The liquid phase slurry has a higher thermal conductivity than pure water.

The biochemical relationships in anaerobic digestion after thermal hydrolysis at Davyhulme

AbstractThe commissioning of the largest thermal hydrolysis plant in the world at Davyhulme, Manchester involved detailed analysis of the digestion process. The plant consists of eight digesters, 20 thermal hydrolysis reactors and a maximum throughput of 121 000 tDS/year.The plant was converted from conventional digestion with a loading rate of 1.25 kgVS/m3/day to digestion fed with thermally hydrolysed sludge with a loading rate of 4.16 kgVS/m3/day. At the start of the commissioning and ramp‐up of the loading rate, control actions were based on acid/alkalinity, pH and foaming; however, it was found that the methane concentration was the parameter that changed quickest during digester instability. The monitoring was changed during commissioning to use methane concentration as the primary control parameter.It was found that the rate of increased organic loading is dependent on the availability of seed biomass already acclimatised to thermally hydrolysed feed sludge and the presence of a high alkalinity buffer.

Dynamic modeling and validation of a lignocellulosic enzymatic hydrolysis process – A demonstration scale study

The enzymatic hydrolysis process is one of the key steps in second generation biofuel production. After being thermally pretreated, the lignocellulosic material is liquefied by enzymes prior to fermentation. The scope of this paper is to evaluate a dynamic model of the hydrolysis process on a demonstration scale reactor. The following novel features are included: the application of the Convection-Diffusion-Reaction equation to a hydrolysis reactor to assess transport and mixing effects; the extension of a competitive kinetic model with enzymatic pH dependency and hemicellulose hydrolysis; a comprehensive pH model; and viscosity estimations during the course of reaction. The model is evaluated against real data extracted from a demonstration scale biorefinery throughout several days of operation. All measurements are within predictions uncertainty and, therefore, the model constitutes a valuable tool to support process optimization, performance monitoring, diagnosis and process control at full-scale studies.

열가용화 반응기 최적 설계를 위한 하수슬러지 열전도 특성

열가용화 반응기 최적 설계를 위한 하수슬러지 열전도 특성

Effects of vapor pressure on thermodynamic equilibrium in multiphase flow for thermochemical hydrogen production

This paper examines the effects of H2O vapor pressure on the equilibrium conditions of a CuCl2 hydrolysis reactor in the thermochemical Cu–Cl cycle of hydrogen production. A new predictive model is developed to determine the minimum steam requirement in the reactor based on the chemical equilibrium condition, reactor pressure and fraction of gaseous reactant. Experimental data, at three separate vapour pressures of steam, compared well with the new predictive formulation.

Dynamic Characteristics and Speed Control Strategy of Cellulose Hydrolysis Reactor at High Solids Loading

Abstract This article put emphasis on systematic research and development on cellulose hydrolysis reactor. The simultaneous saccharification and fermentation of lignocellulosic was carried out in a 5-L reactor at high solids loading of corn stover (25%, w/w). The dynamic characteristics of reactive system were examined. The experimental results showed that the lignocellulosic biomass experienced a series of morphology evolution and viscosity variation. This evolution was a typical event caused by solid reactive processing, and it constituted the basis of a new geometrical configuration of reactor (specifically hybrid impeller). The minimum rotational speed of the impeller was proposed based on the Coutte flow analogy and the yield stress concept. The macroscopic performance of the reactor changed significantly with time. In view of this effect, the operating strategy of the impeller was determined.

The effects of hydride chemistry, particle size, and void fraction on micro fuel cell performance

This paper explores the effects of fuel chemistry and pellet configuration (void fraction, particle size) on MFC reaction rate and yield. Candidate hydrides were evaluated based on their suitability in a MFC using water vapor-driven hydrolysis, and lithium aluminum hydride (LiAlH4) was selected for evaluation. Hydrogen evolution tests were performed in a hydrolysis reactor with three particle size distributions (5 μm, 20 μm, and 50 μm in mean diameter) and at three initial void fractions (86%, 71%, 43%). Void fraction and particle size are found to affect reaction rates, but have no impact on reaction yields (all were ∼100%) within the range tested. Higher void fraction and smaller particle size are correlated with faster reaction rates.Electrical discharge tests are performed on a MFC at a constant potential of 1.2 V at three particle sizes (5 μm, 20 μm, 50 μm) at a 32% initial void fraction. Tests in the MFC reveal the strong impact of particle sizes on reaction rates, and show that reaction rates decrease with increasing particle size. Reaction yields are lower (90–93%) in the MFC, which is attributed to a small hydrogen leak. The energy density of the MFC is 1003 Wh L−1, the highest reported to date.

High stability of immobilized β-d-galactosidase for lactose hydrolysis and galactooligosaccharides synthesis

β-d-Galactosidase from Kluyveromyces lactis was immobilized on glutaraldehyde-activated chitosan and used in a packed-bed reactor for the continuous hydrolysis of lactose and the synthesis of galactooligosaccharides (GOS). The biocatalyst was tested for its optima pH and temperature, thermal stability in the presence of substrate and products, and operational stability. Immobilization increased the range of operational pH and temperature, and the enzyme thermal stability was sharply increased in the presence of lactose. Almost complete lactose hydrolysis was achieved for both milk whey and lactose solution at 37°C at flow rates up to 2.6mLmin−1. Maximal GOS concentration of 26gL−1 was obtained at a flow rate of 3.1mLmin−1, with a productivity of 186gL−1h−1. Steady-state operation for 15 days showed the reactor stability concerning lactose hydrolysis.

The Modification for Increasing Productivity at Hydrolysis Reactor with Jatropha Curcas Linn Capsule Husk as Bio-Methane Feedstocks at Two Stage Digestion

Indonesia energy depends on fossil fuel which its availability get decrease; the price get higher day by day and the environment impact get worse on global warming. As tropical and agricultural country, Indonesia has plenty of bio- mass; therefore it was feasible to develop bio-fuel. In other, bio-fuel production must be wise because there were competition among food – feed – fuel. Jatropha curcas Linn (JCL) was one of non-edible bio-fuel resources, but there was mistake in development at Indonesia. This paper describe 8th study of gaseous bio-fuel from bio-methane with capsule husk as feedstocks, the waste of Crude Jatropha Oil (CJO). The study was conducted in Research Farm PT. Bumimas Ekapersada, Bekasi, West Java, from October until December 2011 to enhance the development of liquid bio-fuel – CJO/bio-diesel and gaseous bio-fuel – bio-methane in the concept of bio-refinery. Bio-methane was modern cooking fuel and the most efficient energetically. The utilization of industrial waste such as capsule husk will not compete with the food, but one of the problem was its low density, so the husk will float in the substrate. The problem can be solved by two stage digestion process, where hydrolysis reactor as process controlling. HDPE plastic drum with the volume of 160 liter was used as hydrolysis reactor. The reactors were arranged using Randomized Complete Design, three replications. The observed parameters were pH, temperature, substrate volume, volatile solid concentration, and acetic acid concentration This paper was focused on reporting of application technology modification on placement of ballast as oppressor substrate in hydrolysis reactor. 19kg of cement slabs is used to suppress 13kg dried husk (DH) + river water with the ratio 1: 8. The ballast was installed on 4, 7, 10 and 14 days of harvest retention time of hydrolysis substrate. The result showed ballast application can increase of hydrolysis substrate volume from 33.19% until 47.25% even no significantly different by statistical analysis. There was increasing in acetic acid concentration (93.27% - 128.51%) and statistical analysis showed significantly different on 4 days treatment. There was increasing on hydrolysis solution production on 4 days treatment (229.48%) and it was significantly different according statistical analysis. As the conclusion, the usage of 19kg ballast as oppressor can increase hydrolysis solution productivity on 160 liter HDPE hydrolysis reactor with concentration 1: 8 on 4 days harvest retention time.

Nitrogen carrier gas flow for reduced steam requirements of water splitting in a packed bed hydrolysis reactor

This paper presents new experimental data and modeling of a copper(II) chloride (CuCl2) hydrolysis reactor for thermochemical hydrogen production with the Cu–Cl cycle. A hydrated nitrogen stream reacts with CuCl2 particles at various temperatures between 365°C and 400°C to investigate the reaction extent of steam in the endothermic reactor. Thermal decomposition of the solid reactant is examined by monitoring the chlorine production in the gaseous effluent. The theoretical maximum steam conversion is calculated from the Gibbs reaction energy and compared with the experimental results via the reaction quotient. The results of this paper provide significant new data to achieve higher conversion efficiencies of steam in the Cu–Cl cycle than previously obtained in past experimental and predictive data.

Steam flow effects on hydrolysis reaction kinetics in the Cu–Cl cycle

Abstract In this paper, the effects of an inert carrier gas and steam flow on the reaction kinetics of a CuCl2 hydrolysis reactor are examined for the thermochemical copper-chlorine (Cu–Cl) cycle of hydrogen production. Experimental data from two packed bed reactors, at three separate vapour pressures of H2O in the gaseous input stream, are investigated in terms of the transient conversion efficiencies and reaction kinetics. The results show that the transient reaction rate reduces by over 75% as the reaction progresses and physical resistances develop in the reactor. The effects of system temperature and reactant flowrate on the reaction rate are also investigated with experimental data. The results of this paper show that by reducing the steam density, the variability in reaction rate can be decreased. These results can be used to predict the reaction kinetics, allowing residence time and transport properties to be more effectively considered.

Use of an electrodialytic reactor for the simultaneous β-lactoglobulin enzymatic hydrolysis and fractionation of generated bioactive peptides

The enzymatic hydrolysis of β-lactoglobulin and the fractionation of peptides were performed in one step in an electrodialysis cell with ultrafiltration membranes stacked. After 240min of treatment, 15 anionic and 4 cationic peptides were detected in the anionic and cationic peptide recovery compartments. Amongst these 15 anionic peptides, 2 hypocholesterolemic, 3 antihypertensive and 1 antibacterial peptides were recovered and concentrated with migration rates ranging from 5.5% and 81.7%. Amongst the 4 cationic peptides, the peptide sequence ALPMHIR, identified as lactokinin and known to exert an important antihypertensive effect, was recovered with an estimated 66% migration rate. To our knowledge, it was the first attempt to perform hydrolysis under an electric field and to simultaneously separate anionic and cationic peptides produced.

Interfacial thermodynamics and X-ray diffraction of hydrolysis products in multiphase reacting flow of the Cu–Cl cycle

This paper examines the chemical equilibrium and gaseous product fraction of a multiphase gas–solid flow involving hydrolysis of copper (II) chloride and steam in a packed bed reactor. The effectiveness of the water splitting process has a significant impact on the efficiency of the thermochemical copper–chlorine (Cu–Cl) cycle for hydrogen production. A thermodynamic analysis of the HCl fraction in the gaseous effluent is presented, along with a predictive model of solid particle conversion based on the reaction temperature and pressure. Experimental results are presented for a horizontal packed bed reactor which exposes a low steam flow rate to a large volume of solid CuCl2 in the packed bed reactor. The predicted and experimental results demonstrate that an HCl fraction above 0.3 can be achieved within the hydrolysis reactor, thus allowing effective integration between hydrolysis and downstream electrolytic hydrogen production steps in the Cu–Cl cycle, without costly HCl/steam separation processes.

Immobilization of ß-galactosidase from Kluyveromyces lactis on Eupergit® C and Properties of the Biocatalyst

Abstract The main goal of this study was to investigate the immobilization of commercial ß-galactosidase from Kluyveromyces lactis (Lactozym®) on Eupergit® C. A Plackett-Burman design was proposed. The ionic strength and pH were the variables that presented significant effect (p<0.1) on immobilization. The increase in the ionic strength from 0.1 to 1.5 M and the increase in pH from 6.6 to 7.4 represented an increase of 28.56% and a reduction of 18.19% in the immobilization yield, respectively. At 25°C, pH 6.6, ionic strength of 1.5 M, immobilization for 8 h, 1 mM of divalent magnesium ion and 0.4 mL of enzyme added, reached 85% immobilization yield. The free and immobilized enzymes were characterized. pH and temperature profiles showed maximum activity at pH 6.6 and 45°C, for both free and immobilized enzymes. There was a gain in thermal stability with enzyme immobilization and there was an increase of about four times in the half-life of the immobilized derivative at 45°C (from 0.43 h to 1.78 h). This greater thermal stability was also made clear through the calculation of thermodynamic parameters (ΔH, ΔG and ΔS). Km values, 30.33 mM and 104.00 mM for free and immobilized enzymes, respectively, represented a reduction in substrate affinity after immobilization, possibly owing to stereo-conformational factors. In a batch reactor for lactose hydrolysis from cheese whey, an increase in lactose conversion with immobilization was observed at 40°C and 45°C (90.43% and 65.36%, respectively) in relation to the free enzyme (84.17% and 39.58%, respectively).