fermenter

In Egypt, significant emissions arise caused by rice straw burning on the field. The total amount produced yearly about three million Mg, essential nutrients and organic matter are lost. The combined energy and material utilizations of rice straw can realize an important contribution to climate protection and resource conservation. To produce bio-ethanol from rice straw, there are four steps that should be taken: 1-Chop rice straw; 2-Mill rice straw; 3-Rice straw sterilization; and 4-Fermentation the milled rice straw in the fermenter using yeast micro-organism.
The present investigation included; manufacture fermenter locally, using computer design software Version 4.0, and techno-economic study using three proposed fermenters scales (300, 600 and 900 litres capacity) at Central Laboratory for Agricultural Climate (CLAC), Dokki, Agricultural Research Center (ARC), Giza, Egypt. A cost-benefit analysis approach was calculated and total return for the three scenarios was estimated for different percentages of ethanol extraction (15, 17 and 20%).
The obtained results indicated that, using fermenter 900 litres capacity
(third scenario) for 20% of ethanol extraction was the economical and effective one to produce bio-ethanol appropriate for small growers; where profit value was USD 566. The net present value at discount rate (D.R) of 30% was estimated to be a positive value of USD 1.096. The benefit cost ratio (B/ C) at the same D.R. was estimated to be 1.22; and the internal rate of return (IRR) reached about 30%.

Industrial fermentation is an interdisciplinary science that applies principles associated with biology and engineering. The biological aspect focuses on microbiology and biochemistry. The engineering aspect applies fluid dynamics and materials engineering. Industrial fermentation is associated primarily with the commercial exploitation of microorganisms on a large scale. The microbes used may be natural species, mutants, or microorganisms that have been genetically engineered. Many products of considerable economic value are derived from industrial fermentation processes. Common products such as antibiotics, cheese, pickles, wine, beer, biofuels, vitamins, amino acids, solvents, and biological insecticides and pesticides are produced via industrial fermentation.

BACKGROUND: The current understanding and implementation of continuous mixing of non-Newtonian fluids is insufficient to ensure good mixing in many cases. In this study, the dynamic response of the continuous mixing of xanthan gum solution, which is a pseudoplastic fluid with yield stress, was quantified using a dynamic model that incorporated non-ideal flows within the mixing vessel. The model allowed for two parallel flow paths through the tank: (1) a channeling zone and (2) a mixing zone.RESULTS: Dynamic tests were made using the frequency-modulated random binary input of a brine solution with the feed to determine the magnitude of non-ideal flows. The extent of flow bypassing the mixing zone and the effective mixed volume were determined from dynamic tests and used as mixing quality criteria. We explored the effect of impeller speed, impeller type, feed flow rate through the mixing tank, fluid rheology, and feed and exit location on the degree of channeling and the fraction of fully mixed volume. Tests show that when the surface of the cavern created by impeller approaches the tank wall, the bottom of the tank, and the surface of the fluid within the mixing vessel, the percentage of non-ideal flow approached zero.CONCLUSION: This study identifies important criteria for continuous mixing vessels that will improve mixing efficiency. By applying these findings, a reduction in the extent of non-ideal flow can be achieved, which will improve the quality and control of the continuous mixing processes such as continuous high-viscosity reactor, continuous fermenter, and continuous solid–liquid mixing. Copyright © 2008 Society of Chemical Industry

Scale-up techniques from the literature have been compiled and reviewed for applicability to Escherichia coli and yeast processes. The consistency of design and operating parameters for the pilot scale vessels in an existing fermentation pilot plant, ranging in nominal volume from 100 l to 19,000 l, was established and compared favorably with approaches found in the literature. Differences were noted as a function of parameters such as fermentor scale, vessel geometry, agitator type/size and ungassed/gassed power input. Further analysis was conducted using actual fermentation data for historical and recent development processes collected over a 10-year-period, focussing on operating conditions at peak culture oxygen uptake rates. Scale-up estimates were performed based on geometric similarity, agitator tip speed, gassed power per unit volume and mixing time. Generally, scale-up calculations from the 280 l scale were most similar to the parameters of installed equipment. Scale-up from the 30 l laboratory scale typically underpredicted parameters with scale-up from the 280 l scale being most appropriate. The 19,000 l fermentor installation was notably different in geometric similarity from the 280 l-1900 l scales since its design was meant to accommodate a wide range of operating volumes. Analysis of historical and recent processing performance was conducted for single cell bacterial or yeast fermentations which challenged peak operating conditions of the fermentors. Identification of key issues associated with scale-up for these specific pilot plant vessels was believed to be critical to efficient process development, clinical material production, and expected process transfer to a manufacturing facility.

ABSTRACTNXL104, a novel β-lactamase inhibitor, was tested at a constant concentration of 4 μg/ml in combination with ceftazidime (CAZ), with and without added metronidazole, against 396 β-lactamase-producing strains of anaerobic bacteria. MIC50/MIC90values forBacteroides fragilisand theB. fragilisgroup were 8/16 and 64/>128 μg/ml, respectively. Although CAZ-NXL104 had limited activity against most anaerobic strains, in combination with metronidazole it shows potential for treating mixed infections involving resistantEnterobacteriaceaeand anaerobes.

Introduction: The introduction to this paper deals with the question of defining fire-prevention distances for constructions in a modern energy enterprise operating on alternative energy sources, which can also simultaneously produce gas, electricity and heat from agricultural waste. The purpose, object and subject of the research are defined, and the basic methods used during the scientific work are presented. The analysis of the process of biogas production technology, which includes the indication of the most dangerous technological structure in the biogas production complex also involves an analysis of the existing means of fire protection, including the main technological equipment.
Methods: The first part of the article gives a general description of the object, its constructive elements and scenarios of the emergence of a hazardous situation, which can lead to a fire or explosion in the fermenters. The effect of the size of the hole through which the gas flows and burns on the diameter of the flame and its temperature, creating a hazard for adjacent structures, was investigated. The results of calculations of the excess pressure of the explosion of biogas in the fermenter, which can occur as a result of an emergency situation, are demonstrated. The integrity of the fermenter elements was determined in the conditions of an excess explosion pressure, and the effect of the excess explosion pressure on the calculation of safe distances
was demonstrated. The main part of the article defines the type of deformation in the main structural elements of the most dangerous structure in the complex (complete or partial destruction or damage) and, to a reasonable extent, the consequences to which this destruction can lead. The effect of the size of the hole through which the gas flows and burns on the diameter of the flame and its temperature, which creates a hazard for adjacent structures, was investigated. Using the “FlowVision 2.5” software packages and “MathCaD” software suites, the schemes of impact of the main forces on the elements
of the fermenter’s biogas plants and the graphical models of the development of combustion in the fermenter during a possible fire, including the initial stage of burning and the fire climax, are presented. Based on the results of calculations for the scenario of the most dangerous accident, the maximum possible values of the height and radius of the flame, the cross-sectional area of the flame and the flame temperature are determined. The algorithm for calculating the safe distances between fermenters for the production of biogas is given. A justification for the minimum fire distances between the
fermenters for the safe operation of the biogas production is given.
Results and conclusions: The final part contains the main results of the research, in particular, of the actual scientific and practical task of ensuring explosion safety in biogas production. Furthermore, the method of estimating the safe distances between the fermenters for biogas production is substantiated.
Conclusions on the results of scientific work are presented and a list of literary sources used by the authors is indicated.
Keywords: fire safety, fermenter, biogas, fire distance, fire breaks, fire modeling
Type of article: original scientific article