Bench type reactor

Aspects of coal liquefaction have been much researched, particularly with the re-emeigence of interest caused by the oil crisis in the 1970 s. The type of reactors used in the studies has been various, ranging from small bomb type microautoclaves through larger autoclaves and bench-scale reactors to larger scale pilot or demonstration plants. The use of differently sized and designed high pressure equipment for liquefaction studies further complicates an already complex system and allows only limited comparison of results. 

All three types of reactors mentioned in Table 8 are used for the quaUty control during the preparation and the use of monolithic systems. Additionally, microreactors are used for the development of new catalysts, whereas bench-scale reactors are used for reactor design. Pilot-scale systems have been used for the determination of the activity during the lifetime of the monolith. 

Chapter 9 focuses on the modeling of a bench-scale reactor in which hydrodemetallization and hydrodesulfurization of Maya crude oil is carried out. All of the aspects that need to be taken into consideration for modeling this type of reactor are described, such as stoichiometric coefficients, reaction rate coefficients, and transport and thermodynamic properties. 

Decalin with Superheated Liquid-Film-Type Catalysis by Use of Bench-Scale Continuous Reactor.458... 

For the purpose of demonstrating the superheated liquid-film-type catalysis in a continuous operation on a bench scale, catalytic dehydrogenation of decalin using a continuous reactor together with a new supporting material was investigated [10,11]. 

In this chapter, we consider nonideal flow, as distinct from ideal flow (Chapter 13), of which BMF, PF, and LF are examples. By its nature, nonideal flow cannot be described exactly, but the statistical methods introduced in Chapter 13, particularly for residence time distribution (RTD), provide useful approximations both to characterize the flow and ultimately to help assess the performance of a reactor. We focus on the former here, and defer the latter to Chapter 20. However, even at this stage, it is important to realize that ignorance of the details of nonideal flow and inability to predict accurately its effect on reactor performance are major reasons for having to do physical scale-up (bench —> pilot plant - semi-works -> commercial scale) in the design of a new reactor. This is in contrast to most other types of process equipment. 

The idea of using fluidized bed as both uniform light distribution and an immobilizing support for photocatalysts has been originally proposed and theoretically evaluated by Yue and Khan [3]. Experimental application of this idea has been demonstrated by Dibble and Raupp [4] who designed a bench scale flat plate fluidized bed photoreactor for photocatalytic oxidation of trichloroethylene (TCE). Recently, Lim et al. [5,6] have developed a modified two-dimensional fluidized bed photocatalytic reactor system and determined the effects of various operating variables on decomposition of NO. Fluidized bed photocatalytic reactor systems have several advantages over conventional immobilized or slurry-type photocatalytic reactors [7,8]. The unique reac-... 

The selection requirements for each of the components of the SCWO system for treating a variety of waste types comes from environmental regulations, waste characteristics, and cost and safety criteria. Similar to the bench-scale experimental design, the major components to be included in the SCWO design involve three main subsystems (influent introduction, reactors, and effluent removal systems). Other auxiliary systems such as heat exchangers and effluent exhaust systems must also be designed. In addition, for scale-up operations, the waste pretreatment and handling systems have to be considered. Fig. 10 shows a schematic of a complete system. 

For scale-up operations, the selection of the reactor is considered to be the key element in designing SCWO systems. Environmental regulations set the requirement for the destruction efficiency, which in turn sets requirements on the temperature and residence time in the reactor (as an example, the required DRE is 99.99% for principal hazardous components and 99.9999% for polychlorinated biphenyls, PCBs). The reactor parameters for the scale-up designs can be extrapolated from the available bench-scale data. A detailed discussion on available reactor types is given below. 

Whereas the tank type and the transpiring wall type are experimentally operated in bench scale rigs, the tubular reactor with multiple feedpoints for oxygen and quenching water is already commercialized for the treatment of solutions, such as long-chain alcohols and amines, without the risks arising from salt formation and corrosive compounds. 

Laboratory studies have shown that omega (MAZ structure type) based paraffin hydroisomerization catalyst shows higher activity than mordenite based catalyst and better selectivity, i.e. higher octane due to higher yield of di-branched paraffins compared to mordenite performance (17). The isomerization of a C5/C6 cut at 15 bar results in a final calculated RON of 80.4 for the alumina bound dealuminated PtH-MOR catalyst supplied by IFP with undisclosed (most likely similar) Si/Al ratio, measured at 265 °C compared to a RON value of 80.9 for an alumina bound dealuminated PtH-MAZ catalyst with bulk Si/Al = 16, measured at 250 °C. Both measurements were performed in a bench-scale tubular reactor with a volume of 50 cm3 of 2 mm diameter extrudates with WHSV of 1.5 h and H2/HC of 4. This... 

The four principal types of reactors used for bench-scale kinetic studies are batch, continuous stirred-tank (CSTR), tubular, and differential reactors. Which of these to choose is essentially a matter of the reaction conditions, available equipment, and the chemist s or engineer s predilections. The discussion here will focus on facets that pertain specifically to quantitative kinetic studies of homogeneous reactions. 

Bench-scale kinetic experiments can be conducted in batch, continuous stirred-tank, tubular plug-flow, or differential reactors. The last of these can be operated with once-through flow or recycle. The advantages and disadvantages of the various types are discussed in Section 3.1. 

Figure 20 presents some results of comparative tests on hydrodesulfurization of a heavy gasoil in a bench-scale and a microflow reactor over two catalysts, both diluted with small particles of silicon carbide. It can be inferred that results are the same irrespective of the reactor scale, the same difference in relative performance of the two catalysts being observed in both reactor types. 

According to this concept, Masuda et al. [75] studied the catalytic cracking of the oil coming from a previous thermal pyrolysis step of polyethylene at 450°C in the bench-scale fixed-bed reactor shown in Figure 3.11. The catalysts employed were different zeolite types REY (rare earth exchanged zeolite Y), Ni-REY (nickel and rare earth... 

A conceptual material balance of a refinery producing 100,000 bbl/ day of fuel oil from coal was calculated (Table IV) based on the bench-scale data obtained by the authors and the published data available. In this projection, a coal containing 7.5% moisture, 10% ash, and 2.5% total sulfur is used as the feed. The hydrogenation can be performed in any type of reactor system in the ranges of 500°-550°C and 2000-3000 psi. The process conditions will be optimized for a coal conversion of about 80%. The hydrocarbon gases produced in the process will be used... 

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