Marzouk Benali

Process Intensification for Drying and Dewatering

Background information on process intensification including the rationale, basic methods in process engineering, and interactions between material streams and processing methods is given. The general rules are then examined with respect to heat and mass transfer intensification, and pertinent to drying techniques and technologies (e.g., microwave drying, pulse combustion drying, intermittent drying, drying by alternation pressure, etc.) are highlighted. Milk processing for powdery product and bakery production is given as an example of process intensification with respect to water evaporation.

THERMAL DEWATERING OF DILUTED ORGANIC SUSPENSIONS: PROCESS MECHANISM AND DRYING KINETICS

ABSTRACT Drying of raw hog manure, a highly diluted suspension of organic and inorganic matter was studied experimentally in the multistage screw-in-trough dryer. Laboratory tests included material characteristics (rheological properties, thermodynamic equilibrium, critical settling point), boiling pattern, and kinetics of convective drying at temperatures from 90 to 120°C and air velocity from 0.5 to 1.5 m/s. Three phases of manure drying were identified, namely boiling and release of volatile compounds, evaporation from viscous liquid, followed by drying of a soft paste, and finish drying of semi-dry granular product. Drying kinetics were quantified in terms of reduced moisture content and a generalized drying curve using the characteristic drying time concept. Field tests were carried out in the pilot multistage screw-in-trough dryer to validate design calculations. ©Her Majesty the Queen in Right of Canada, represented by the Minister of Natural Resources, 2002.

Pulse Combustion Drying: Aerodynamics, Heat Transfer, and Drying Kinetics

The copyright is held by

An Improved Linear Programming Approach for Simultaneous Optimization of Water and Energy

An optimization method based on Mixed Integer Linear Programming (MILP) has been developed for simultaneous optimization of water and energy (SOWE) in industrial processes. The superstructure integrates process thermal streams and optimizes the consumption of water while maximizing internal heat recovery to reduce thermal utility consumption. In this paper, additional concepts have been implemented in the superstructure to target the issues of the pulp and paper processes. Non-Isothermal Mixing (NIM) has been considered at different locations in order to reduce the number of thermal streams and decrease the investment cost by avoiding unnecessary investment on heat exchangers. The concepts of restricted matches and water tanks have been added to the superstructure to adapt it to the pulp and paper case studies. The Integer-Cut Constraint (ICC) technique has been combined with the MILP model to generate systematically a set of optimal solutions to support the decision-making for cost-effective configurations.

A novel MILP approach for simultaneous optimization of water and energy: Application to a Canadian softwood Kraft pulping mill

Abstract An optimization methodology based on Mixed Integer Linear Programming (MILP) has been developed for simultaneous optimization of water and energy (SOWE) in industrial processes. The superstructure integrates non-water process thermal streams and optimizes the consumption of water, while maximizing internal heat recovery to reduce thermal utility consumption. To address the complexity of water and energy stream distribution in pulp and paper processes, three features have been incorporated in the proposed SOWE method: (a) Non-Isothermal Mixing (NIM) has been considered through different locations to reduce the number of thermal streams and decrease the investment cost by avoiding unnecessary investment on heat exchangers; (b) the concept of restricted matches combined with water tanks has been added to the superstructure; and (c) the Integer-Cut Constraint technique has been combined with the MILP model to systematically generate a set of optimal solutions to support the decision-making for cost-effective configurations. The performance of the proposed improved MILP approach has been evaluated using several examples from the literature and applied to a Canadian softwood Kraft pulping mill as an industrial case study. The results indicate that this approach provides enhanced key performance indicators as compared to conceptual and non-linear complex mathematical optimization approaches.

Thermal Processing of Particulate Solids in a Gas-Fired Pulse Combustion System

Abstract An experimental study on thermal processing of particulate solids has been carried out on a valved pulse combustion unit. The test-bench consists of a 60 kW natural gas-fired valved (flappers) pulse combustor having a 4.63 × 10−3 m3 combustion chamber, horizontal tailpipe with variable geometry, and a cylindrical drum. The particulate solid used is clean sand (311 µm and 2646 kg/m3), which flows within the tailpipe and the cylindrical drum located at its end. The sand flowrate was varied from 10 to 50 kg/h and it was heated from 20 to 600°C. Local pressure measurements showed clearly that the propagation of sonic waves remain stable when they are in direct contact with the sand particles. The heating time of sand particles in the pulsed system was found shorter than the one observed when operating with a conventional burner under the same conditions; this resulted in a 25.5% reduction of natural gas consumption. #The copyright is held by

Study of total dry matter and protein extraction from canola meal as affected by the pH, salt addition and use of zeta-potential/turbidimetry analysis to optimize the extraction conditions

Total dry matter and proteins were differentially and preferentially extracted from canola meal (CM) under different conditions. The effect of the extraction medium pH, CM concentration and salt concentrations were found to have different influences on the extractability of total dry matter and proteins from CM. The pH of the extracting medium had the most significant effect. The maximal total dry matter (42.8±1.18%) extractability was obtained with 5% CM at pH 12 without salt addition, whereas the maximal for total protein (58.12±1.47%) was obtained with 15% CM under the same conditions. The minimal extractability for the dry matter (26.63±0.67%) was obtained with 5% CM at pH 10 without salt added and the minimal protein extractability was observed in a 10% CM at pH 10, in 0.01 NaCl. Turbidity and ζ-potential measurements indicated that pH 5 was the optimum condition for the highest protein extraction yield. SDS-PAGE analysis showed that salt addition contributes to higher solubility of canola proteins specifically cruciferin fraction, although it reduces napin extraction.

Nutritional Profile and Carbohydrate Characterization of Spray-Dried Lentil, Pea and Chickpea Ingredients

Although many consumers know that pulses are nutritious, long preparation times are frequently a barrier to consumption of lentils, dried peas and chickpeas. Therefore, a product has been developed which can be used as an ingredient in a wide variety of dishes without presoaking or precooking. Dried green peas, chickpeas or lentils were soaked, cooked, homogenized and spray-dried. Proximate analyses were conducted on the pulse powders and compared to an instant mashed potato product. Because the health benefits of pulses may be due in part to their carbohydrate content, a detailed carbohydrate analysis was carried out on the pulse powders. Pulse powders were higher in protein and total dietary fibre and lower in starch than potato flakes. After processing, the pulse powders maintained appreciable amounts of resistant starch (4.4%–5.2%). Total dietary fibre was higher in chickpeas and peas (26.2% and 27.1% respectively) than lentils (21.9%), whereas lentils had the highest protein content (22.7%). Pulse carbohydrates were rich in glucose, arabinose, galactose and uronic acids. Stachyose, a fermentable fibre, was the most abundant oligosaccharide, making up 1.5%–2.4% of the dried pulse powders. Spray-drying of cooked, homogenized pulses produces an easy to use ingredient with strong nutritional profile.

Integrated Lignin-Kraft Pulp Biorefinery for the Production of Lignin and Its Derivatives: Economic Assessment and LCA-Based Environmental Footprint

Recovery of lignin from Kraft black liquor is already at the commercial scale, and the conversion of lignin into high-value products is considered as one of the means for transforming pulp and paper mills into multiproduct biorefineries. However, this has not led to the widespread production of lignin derivatives because the actual techno-economic and environmental impacts of integrating new processes into existing mills are not well known, and have to be determined on a mill-by-mill basis. Furthermore, the technological readiness levels for some production pathways of lignin derivatives still range between 4 and 6, while they should range between 8 and 9, in practical environments. Therefore, to address such technical, economic, and environmental challenges, multi-criteria analysis is introduced in this chapter to provide the reader with a comprehensive assessment of integrated lignin-based biorefinery processes. The applicability of the approach is demonstrated by means of an industrial case study, involving a lignin recovery rate of up to 100 t/day from a softwood Kraft pulping mill that produces about 1000 air-dry-tonnes per day of bleached pulp. The subsequent conversion of recovered lignin into polyurethane foam and carbon fiber is analyzed, and the importance of the phased transformation of the Kraft pulp mill as well as the impact of subsidies on profitability are demonstrated.

Application of Process Systems Engineering (PSE) Tools in Designing the Biorefinery

Abstract Biorefinery is emerging as a possibility for improving the business model of forest products companies, however introduces significant market, technological and financial challenges which must be systematically addressed. For sustainable design decision making, economic, environmental and social criteria should be addressed. Different tools are required to analyze the performance of potential biorefinery strategies from each of these perspectives. Such tools provide relevant criteria to be used by a multi-criteria decision-making (MCDM) framework. This paper presents a systematic methodology for designing the biorefinery which uses PSE tools, including market analysis, techno-economic study, cost accounting, pinch analysis, life cycle assessment (LCA), supply chain (SC) analysis, and ends with an MCDM framework for identifying promising strategies for a given company. Such methodology aggregates the impacts into sustainability scores and helps evaluate strategies based on an overall performance.