Converter bottle-shaped

For revamps of ammonia synthesis converters, Ammonia Casale offers 1) an in-situ modification of bottle-shaped converters of the Kellogg type, and 2) a three-bed intercooled configuration. The intercooled design is similar in some ways to the Uhde design discussed below213. 

Based on the above general principles, quite a number of models have been developed to estimate pore size distributions.29,30,31-32,33 They are based on different pore models (cylindrical, ink bottle, packed sphere,. ..). Even the so-called modelless calculation methods do need a pore model in the end to convert the results into an actual pore size distribution. Very often, the exact pore shape is not known, or the pores are very irregular, which makes the choice of the model rather arbitrary. The model of Barett, Joyner and Halenda34 (BJH model) is based on calculation methods for cylindrical pores. The method uses the desorption branch of the isotherm. The desorbed amount of gas is due either to the evaporation of the liquid core, or to the desorption of a multilayer. Both phenomena are related to the relative pressure, by means of the Kelvin and the Halsey equation. The exact computer algorithms35 are not discussed here. The calculations are rather tedious, but straightforward. 

So far we have examined the essence of polymers, both natural and synthetic. We have looked at a variety of ways that they are synthesized and studied some of their properties. In this chapter we will find out how we can convert a polymer sample that might be in powder or pellet form into some useful object. This is largely the realm of the engineers, who design the processing equipment and determine the conditions that produce polymeric products with optimum properties. These objects take a wide variety of shapes, including films, fibers, solid parts, hollow containers such as bottles, and foamed objects. 

In nearly all applications of piastics in packaging, the first step is to convert the soiid piastic, usuaiiy in peiiet form, into a meit. This meit can then be shaped using heat and pressure into a usefui form. The equipment used to do this is an extruder. An extruder is used for him and sheet, and is part of a blow molder for bottles. An extruder is also part of an injection molding machine for injection molded or injection blow molded packaging. The extruders used in all of these applications work in a similar manner, but they deliver the melt to the shaping operation differently. We will explore these differences as we proceed. 

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