David R. Jenkins

Plastic layer permeability estimation using a model of gas pressure in a coke oven

A simplified model of heat transfer and internal gas pressure (IGP) in a coke oven, based on the fundamentals of the process, is presented and validated by reference to pilot scale coke oven experiments. The model can be used to describe the generation of IGP at all stages of the coking process, and results developed at the pilot scale coke oven level can be scaled up to operational level using the model. The model is used to show that the permeability at the resolidification end of the plastic layer is a key determinant of the magnitude of the IGP, and ultimately coking pressure. The effect of bulk density on permeability is discussed and the vertical variation of gas pressure in the centre of the oven charge is illustrated.

Effect of coke shrinkage and plastic layer deformation on gas pressure in a coke oven

A plausible mechanism is provided for the generation of internal gas pressure (IGP) in the plastic layer of a coke charge, by relating the formation of low permeability at the outer edges of the plastic layer to the deformability of the plastic material. The amount of lateral shrinkage post-resolidification is shown to be important in constraining the deformation of the plastic material, and hence the generation of low permeability to gas flow. The mechanism provides a natural explanation for permeability variation in the plastic layer, as well as for the linkage between IGP/coking pressure generation and pushing difficulties.

On computational control of flow in airblast atomisers for pulmonary drug delivery.

Among different approaches to successful pharmacotherapy the pulmonary drug delivery (PDD) mode plays an increasingly important role. In this paper PDD systems based on air-blast atomisation have been analysed mathematically. In order to allow the bioengineer to estimate the degree of effectiveness of a specific system prototype and to lay the basic principles for design, a conservation-law-based mathematical model is discussed. Key control parameters that allow improvement in the efficiency of the system have been identified and main characteristics of the system have been analysed numerically as functions of these parameters.