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71.
Sari Heikkinen Leila Alvila Tuula T. Pakkanen Terhi Saari Pekka Pakarinen 《应用聚合物科学杂志》2006,100(2):937-945
Drying, water fractions, and water distribution were investigated for pine, birch, and reed pulps and pine–birch, pine–reed, and pine–birch–reed pulp mixtures. Gravimetrically determined drying times showed that the drying rates of the pulps decreased at two to four inflection points. Characterizations of the dried pulps by differential scanning calorimetry (DSC) showed a faster removal of free water than freezing and nonfreezing bound waters; all decreased simultaneously, however. DSC also revealed the critical water contents at which the free water and freezing bound water disappeared. The gravimetrically determined inflection points of the drying curves corresponded with the critical points determined by DSC. NMR line widths and images produced by 1H‐NMR imaging revealed the nature and regions of the pulp drying. The constant growth rate of the NMR line widths with decreasing water content appeared to change at two inflection points, which fell approximately in the same water content regions as the inflection points of the drying curves. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 937–945, 2006 相似文献
72.
Drying subbituminous coal has never been practiced commercially. The commercial dryers built to date have been designed for drying surface moisture in conjunction with upstream coal preparation facilities. This type of drying is mainly controlled by input energy and the basis of the design is an energy balance. In drying inherent moisture from subbituminous coal, the thermal conductivity of the coal and the diffusion of molecular water within coal particles impose limitations on the process conditions. Energy input and solids residence time in the dryer have to be controlled properly for simultaneously balancing the heat and mass transfer within the coal particles. Improper control of either parameter can cause fires and explosions during the key steps of the drying process—drying and cooling
In parallel to the Anaconda coal drying pilot plant program, a cross-flow, fluid-bed coal drying/cooling process simulator was developed for: (1) understanding the drying phenomena on an individual particle basis; (2) analyzing potential risks and safety limits, and (3) designing the Anaconda pilot plant program
The development of the process simulator was based on both first principles and laboratory data and can be divided into two phases:
1 Development of a semi-mechanistic drying model for Powder River Basin subbituminous coal employing an analytical solution of the diffusion equation
2.Formulation of a fluid-bed cross-bed cross-flow dryer/cooler simulator employing simultaneous heat and mass transfer
This model was validated against process variables data taken on a 4 tph pilot plant. An operable range, or process envelope, has been developed through the pilot plant experience and the process simulation study. Based on the model predictions, an uncertainly range was defined in the design recommendations of a pioneer coal drying plant in scale-up. 相似文献
In parallel to the Anaconda coal drying pilot plant program, a cross-flow, fluid-bed coal drying/cooling process simulator was developed for: (1) understanding the drying phenomena on an individual particle basis; (2) analyzing potential risks and safety limits, and (3) designing the Anaconda pilot plant program
The development of the process simulator was based on both first principles and laboratory data and can be divided into two phases:
1 Development of a semi-mechanistic drying model for Powder River Basin subbituminous coal employing an analytical solution of the diffusion equation
2.Formulation of a fluid-bed cross-bed cross-flow dryer/cooler simulator employing simultaneous heat and mass transfer
This model was validated against process variables data taken on a 4 tph pilot plant. An operable range, or process envelope, has been developed through the pilot plant experience and the process simulation study. Based on the model predictions, an uncertainly range was defined in the design recommendations of a pioneer coal drying plant in scale-up. 相似文献
73.
N. J. Thakor S. Sokhansanj I. McGregor S. McCurdy 《Journal of the American Oil Chemists' Society》1995,72(5):597-602
Hydrothermal pretreatments for loosening the hull of Westar canola (Brassica napus L.) to promote dehulling of the seeds were investigated. The samples tested had on average 14.5% hull on a mass basis. Conditioning
treatments involved soaking the seeds in distilled water or exposing the seeds to saturated steam. The moistened seed was
treated with one of the following drying methods: unheated-air drying, infrared drying, and fluidized-bed drying. The dried
grain was milled in an abrasive dehuller to break the hulls loose. The hulls were removed from the mix by aspiration. The
treated seeds yielded a minimum of 11.4% to a maximum of 14.9% of the seed mass as the hull fraction. Nontreated seeds yielded
9.4% of the seed mass in hull fraction after abrasive dehulling and aspiration. Among treatments, raising the moisture content
of the whole seed from 6 to 15% by exposure to steam, followed by drying in a fluidized bed, resulted in the maximum percent
dehulling efficiency. The hull fraction contained about 24% crude fiber, 18% oil, and 18% protein on a dry-mass basis. 相似文献
74.
The paper is focused on identifying error sources in computational fluid dynamics(CFD) predictions of a spray drying process. Seven groups of drying and atomisation parameters were selected for analysis and 13 simulation trials were performed. The theoretical results were compared with experimental data and sensitivity of the simulation results to the analysed factors was determined. The following parameters affecting the accuracy of CFD spray modelling were found: gas turbulence model, particle dispersion, atomising air, initial parameters of atomisation and heat losses to the environment. A major difference in the errors committed during modelling of spray drying process for fine and coarse sprays was observed. 相似文献
75.
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77.
气干型不饱和聚酯树脂 总被引:3,自引:0,他引:3
气干型不饱和聚酯树脂是常温交联的热固性树脂。其性能优良,光泽度高,丰满度好,是优良的饰面材料。它的组成的原子灰,是理想的更新换代产品,广泛适合于金属基材的嵌填。 相似文献
78.
分析了氯气的洗涤冷却效果等影响氯气干燥质量的因素,提出改进氯水洗涤塔洗涤效果、稳定干燥塔运行工况、降低氯气中酸雾夹带以及提高酸雾捕集效果的措施。 相似文献
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