Plant reactor size reduction

We believe the next phase of development of the LP methanol process will relate to reduction in capital costs. This will become particularly significant as plant sizes increase. ICI is dedicated to continued further development of its catalyst to improve activity and life. This will lead to a reduction in the reactor size and catalyst volume and, consequently, to a reduction in capital cost. 

Even when the laboratory test reactor is intended to be representative in a reaction kinetic sense only (thus waiving the demand for correspondence in terms of pressure drop and hold-ups), the process performance data can be affected by differences in mass transfer and dispersion caused by scale reduction. When interphase mass transfer and chemical kinetics are both important for the overall conversions, the above test reactor, which is a relatively large pilot plant reactor, cannot be further reduced in size unless one accepts deviations in test results. 

Parallel to PI, a number of equipment vendors have been developing a number of interesting new apparatuses. This new equipment is mainly focussed on the reaction section in the chemical process. Although the size of plant often is determined by the downstream processing part, i.e. separating sections such as distillation and extraction, a first step in the PI approach might be the size reduction of the reactor. 

Table 3-9 shows operating points that yield the highest cycle efficiencies for 2-2-2s and 3-3-3s plant architectures. Note that for a 2-2-2s plant architecture, a reduction of 18.5% in rotational speed, 45,000 to 36,668, and a reduction of reactor outlet temperature from 1150 to 1091 K is required to operate steady state at 50% alternator load capacity. Due to the cycle efficiency penalty of operating additional engines at lower speed, and lower turbine inlet temperature, the reactor and heat rejection system need to be sized larger to support full power operation. Additional detail regarding this mode of operation is provided in Reference 3-2. 

Attrition of particulate materials occurs wherever solids are handled and processed. In contrast to the term comminution, which describes the intentional particle degradation, the term attrition condenses all phenomena of unwanted particle degradation which may lead to a lot of different problems. The present chapter focuses on two particular process types where attrition is of special relevance, namely fluidized beds and pneumatic conveying lines. The problems caused by attrition can be divided into two broad categories. On the one hand, there is the generation of fines. In the case of fluidized bed catalytic reactors, this will lead to a loss of valuable catalyst material. Moreover, attrition may cause dust problems like explosion hazards or additional burden on the filtration systems. On the other hand, attrition causes changes in physical properties of the material such as particle size distribution or surface area. This can result in a reduction of product quality or in difficulties with operation of the plant. 

However, the integration of PIM also creates synergy in the development of intensified processes, novel product forms, and size dependent phenomena, which in turn provides novel intensified processes. Process intensification-miniaturization is seen as an important element of sustainable development because it can deliver 1) at least a 10-fold decrease in process equipment volume 2) elimination of parasitic steps and unwanted by-products, thus eliminating some downstream processing operations 3) inherent safety because of reduced reactor volume 4) novel product forms 5) energy, capital, and operating cost reduction, and an environment friendly process 6) plant mobility, responsiveness, and security and 7) a platform for other technologies. 

The capital cost of FBR is about 1.5 to 2.5 times that of thermal reactors and significant cost reduction is essential for its successful deployment. Cost reduction measures adopted in LMFBR include elimination of ex-vessel sodium storage, decrease in number size of components of heat transport system, compact layouts, increasing operating temperature, increasing plant life and increasing fuel bumup. 

After completion of the bench and laboratory pilot plant tests, this process step was tested in the desulphurisation reactor of the CX plant of Tonolli Canada. Batches of 8 tonnes were used in order to define all the reaction parameters. Sodium sulphide was used as the sulphidization reactant and a sodium sulphate solution was produced. The results of these tests on an industrial size reactor confirmed the performance obtained during the laboratory investigations. Taking advantage of these tests, PAQUES Biosystem B.V., a Dutch company that has significant expertise in biological sulphate reduction, applied its experience to achieve the same results in a safer and environmentally more friendly way. 

The fire load density of the compartment for the additional water supply vessel inside the reactor building has been treated quite pessimistically. Although the plant documentation provided a fire load of 560 Ml resulting in a fire load density of less than 90 Ml/m for the compartment floor size of approx. 50 m, the compartment has been included in the analysis due to the permanently as well as temporarily available fire loads. Here, again the CDF may be reduced by installation of adequate fire detectors or by a reduction of fire loads. 

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