Browsing by Author "Leeke, Gary"

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    Analysis of curcumin precipitation and coating on lactose by the integrated supercritical antisolvent-fluidized bed process
    (Elsevier, 2017-12-12) Matos, Ravenna Lessa; Lu, Tiejun; McConville, Christopher; Leeke, Gary; Ingram, Andrew
    Dry powder formulations with potential application in pulmonary drug delivery were produced by integrating the Supercritical Antisolvent (SAS) process with a fluidized bed (FB) under pressure. The simultaneous precipitation and coating of curcumin on lactose was performed in a single step combining the advantages of both processes. Ethanol and acetone were used as solvents. The effects of operating parameters: pressure, temperature, drug-lactose mass ratio, solution flow rate and solution concentration on the drug size, morphology and yield were investigated. Due to the high degree of mixing in the fluidized bed, a uniform coating of curcumin onto lactose was achieved with loading efficiency varying from 71.0 to 93.3% and curcumin particle size between 0.41 and 12.08 μm. Solvent-free curcumin particles with reduced crystallinity were produced while the physicochemical properties of the raw materials were not changed.
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    Chlorine removal from the pyrolysis of urban polyolefinic waste in a semi-batch reactor
    (Elsevier, 2020-12-11) Torres, Daniel; Jiang, Ying; Sanchez Monsalve, D. A.; Leeke, Gary
    The pyrolysis of urban chlorine-containing polyolefinic plastic waste with simultaneous retention of HCl is investigated. Different chemical removers based on sodium, calcium and zinc bases, and different adsorbents based on alumina or zeolites were used inside the reactor or in downstream hot filters, respectively, for chlorine removal and upgrading of pyrolysis oils. Initially, polyolefin waste (POW, containing a 98.5 wt% polyolefins) was thermogravimetrically pyrolyzed to determine its thermal behaviour. Subsequently, chemical removers were mixed with the POW which was pyrolyzed at 480 °C in a semi-batch reactor. The adsorbents were tested separately in hot filters (300 ± 20 °C) downstream of the pyrolysis reactor. After the pyrolysis, the resulting char containing the chemical removers and the absorbents in the hot filters were analysed by FTIR, CHN elemental analysis and ESEM-EDS to determine their respective chlorine contents. The highest chlorine retention was 23.8 wt% for chemical remover when used in direct contact with POW, while a zeolite used in the hot filter (gas streams) gave a chlorine retention of 65.6 wt%. The pyrolytic liquids consisted of mixtures of C7-C40 hydrocarbons made up of olefinic and aliphatic hydrocarbons with a very low presence of aromatics (estimated to be below 3 wt% by HPLC). In most cases, the chlorine removal processes resulted in waxier pyrolytic oils and with a higher degree of branching
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    Data supporting Technology readiness level assessment of composites recycling technologies article
    (Cranfield University, 2016-06-17 11:27) Rybicka, Justyna; Tiwari, Ashutosh; Leeke, Gary
    Data supporting Technology readiness level assessment of composites recycling technologies article
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    Operational and maintenance planning of production and utility systems in process industries
    (Cranfield University, 2019-01) Zulkafli, Nur Izyan BT.; Hanak, Dawid P.; Leeke, Gary
    Major process industries have installed onsite the utility systems that can generate several types of utilities for meeting the utility requirements of the main production systems. A traditional sequential approach is typically used for the planning of production and utility systems. However, this approach provides suboptimal solutions because the interconnected production and utility systems are not optimised simultaneously. In this research, a general optimisation framework for the simultaneous operational and maintenance planning of utility and production systems is presented with the main purpose of reducing the energy needs and resources utilisation of the overall system. A number of industrial-inspired case studies solved show that the solutions of the proposed integrated approach provides better solutions than the solutions obtained by the sequential approach. The results reported a reduction in total costs from 5% to 32%. The reduction in total costs demonstrate that the proposed integrated approach can result in efficient operation of utility systems by avoiding unnecessary purchases of utility resources and improved utilisation of energy and material resources. In addition, the proposed integrated optimisation-based model was further improved with the presence of process uncertainty in order to address dynamic production environment in process industries. However, integrated planning problems of production and utility systems results to large mixed integer programming (MIP) model that is difficult to solve to optimality and computationally expensive. With this regards, three-stage MIP-based decomposition strategy is proposed. The computational experiments showed that the solutions of the proposed MIP-based decomposition strategy can achieve optimal or near-optimal solutions at further reduced computational time by an average magnitude of 4. Overall, the proposed optimisation framework could be used to integrate production and utility systems for effective planning management in the realistic industrial scenarios.