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东北大学毕业设计（论文） 结束语

结束语

历时三个月的毕业设计现在已经基本上结束。在张振伟老师、邓永胜老师和刘阳老师的精心指导下，在师兄师姐和同学们的帮助下，自己的辛勤劳动下，终于完成了这次意义重大的毕业设计工作。在整个设计学习期间，指导老师始终如一地关心作者各方面上的进展，悉心指导了全部研究的各个环节，反复审阅论文稿，提出许多修改意见，为本文的完成付出了很多心血。他们渊博的学术造诣及严谨的治学态度给作者以深刻教诲，深信将受益终身。在论文工作即将完成之际，谨向导师张振伟老师、邓永胜老师和刘阳老师表达我深深的敬意和最真诚的感谢!

通过这次毕业设计，我增长了很多认识，也了解到了许多实际性的问题，同时我了解到机械设计是多么的博大精深。

毕业设计虽然结束了，大学四年的学习生活也即将结束，但这只是人生的一个新的开始。我的知识，特别是在机械设计方面的知识还刚刚是打下了一个良好的基础，学无止境，还有很多问题需要我去研究，去探索。因此，在以后的工作和学习生活中，我将继续努力学习。

最后，我要深深感谢父母对我的关爱和全力支持，他们给了我前进的动力!

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东北大学毕业设计（论文） 结束语

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东北大学毕业设计（论文） 附录（外文翻译）

附录（外文翻译）

外文原文

An overview of innovation in industrial drying: current status and

R&D needs

1. Introduction

Thermal drying has been recognized as an important unit operation as it is energy intensive and has a decisive effect on the quality of most products that are dried commercially. Escalating energy costs, demand for eco-friendly and sustainable technologies as well as the rising consumer demand for higher quality products, have given fresh incentives to industry and academia to devote great effort to drying R&D. Fortunately, this area does not demand a massive perfusion of R&D funds to come up with valuable insights and innovations, with only a few exceptions. Indeed, there is already a sustainable level of R&D support—both in terms of human and financial resources—around the world. Emerging economies of the world, such as China, Brazil, India, etc, have picked up the slack caused by the fully developed economies of the west moving towards nanotechnologies. Overall, the global R&D effort has been rising despite precipitous drops in North America and Europe. With 12–25% of the national industrial energy consumption attributable to industrial drying in developed countries, it is only a matter of time before high energy costs will stimulate further R&D in drying. The fact that tens of thousands of products need to be dried in over a 100 variants of dryers provides major and ample opportunities for innovation. In this paper, we start with the definition of innovation and how it may be intensified. This is followed by a discussion of some new technologies in comparison with the traditional ones, which still dominate the market. The need for industry–academia interaction and a pro-active role of industry—the ultimate beneficiary of all R&D regardless of its origin—is stressed.

2. Conventional versus new drying technologies

It is difficult to make a sharp distinction between what is conventional and what is really new in drying technologies since most of the newer developments are evolutionary,i.e., based on traditional ones; often the transition is seamless and it is not possible to identify where and when it occurred. The following discussion must therefore be taken within this vagueness inherent to the field itself.

Kudra and Mujumdar (1995) have classified and discussed various novel dryers, ranging from laboratory-scale curiosities (e.g., acoustic drying, drying of slurries by impinging sprays

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东北大学毕业设计（论文） 附录（外文翻译）

over a hot surface) to pilot-scale demonstrations (e.g., pulse combustion dryers, ultrasonic spray dryers, impinging stream dryers) to full-scale commercial dryers (e.g., pulsed fluid beds, superheated steam fluid bed/flash dryers, rotary dryers with drying air injected into the rolling bed).A full discussion of the truly bewildering variety of non-conventional dryers is beyond the scope of this presentation. The interested reader may refer to the book by Kudra and Mujumdar (2002) for a comprehensive coverage of the numerous new drying concepts and technologies. The Handbook of Industrial Drying (Mujumdar 1995) is also a source of relevant information.

Table 1 summarizes the key features of the newer dryers as compared to those of conventional ones for drying of various physical forms of the wet feed material. Note that the new designs are not necessarily better than the traditional ones for all products, but they do offer some advantages that may make them a better choice in some applications. Some of them are simply intelligent combinations of conventional dryers.

Table 2 compares some key features of the newer or emerging drying technologies with those of the more commonly used conventional techniques. In terms of the sources of energy there is no difference. However, in terms of how this energy is delivered and transferred to the wet solid there are some significant differences.

In the chemical industry, the most common drying application involves production of dry particulates from pumpable liquids (solutions, suspensions, or slurries), thin or thick pastes (including sludge), or granular solids. Spray and drum dryers are used most commonly for such applications.

Spray dryers today no longer just convert a pumpable liquid to a powder but can be used to produce “engineered” powders with specific particulate size, as well as structure (e.g., agglomerates, granules, or large mono-sized spherical particles). Personnel safety on and around dryers, prevention of environmental pollution, and emphasis on production of a high-quality product at minimum cost are paramount considerations in the design of spray dryers today. With the help of computer simulations, better designs of the dryer chamber and air flows within the dryer have led to minimal wall deposit problems in spray dryers. A new spray dryer concept even uses a flexible canvas cone instead of the usual metallic one. Horizontal spray chamber layouts are also being examined via CFD simulations.

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东北大学毕业设计（论文） 附录（外文翻译）

Table 1 Conventional versus innovative drying techniques

Feed type Liquid suspension Dryer type Drum Spray New techniques Fluid/spouted Spray/fluid beds bed of inert combination Vacuum belt dryers Pulse combustion dryers Paste/sludge Spray Drum Paddle Spouted bed of inert particles Fluid bed (FB) (with solids back-mixing)Superheated dryers Particles Rotary Flash Fluid bed (hot air Superheated steam FBD Vibrated combustion gas)Conveyor dryer bed, Ring dryer, Pulsated fluid bed, Jet-zone dryer Impinging streams Yamato rotary dryer Continuous sheets (coated paper, paper, textiles) Multi-cylinder contact dryers; Impingement dryers Combined impingement/ steam rad-iation Combined impingement and through dryers Impingement and MWor RF or Radiation dryers

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