Process/catalyst development operating conditions

Deep catalytic cracking (DCC) is a commercially proven FCC process for selectively cracking a wide variety of feedstocks to light olefins, particularly propylene. Innovations in catalyst development, operational severity, and anticoking conditions. 

Such a development would parallel extensive experience in successful commercialization of many fixed-bed processes using similar catalysts and operating conditions. The five licensed processes using ZSM-5 catalyst fall in that category. The simplest fixed-bed MTG system was the one which employed dehydration and ZSM-5 reactors. This system was studied extensively in bench-scale units. These studies in a 3 cm diameter by 30-50 cm length reactors were considered to be sufficient for scale-up. 

Of course, the reduced crude conversion process is not 100% efficient. By this it is meant that to date no catalyst and operating conditions have been developed which completely remove saturates, monoaromatics, diaromatics, and alkyl substituents of polynuclear aromatics from the slurry oil. Therefore, to predict slurry oil plus coke yield one must determine what proportion of each molecular type present in the reduced crude feedstock remains in the slurry oil and coke. 

UOP s Isomar process (56,117—119) was originally developed to use dual-functional catalysts. The first-generation catalyst contained Pt and halogen on alumina. Operating conditions using this catalyst were 399°C 1.25 MPa 2 LHSV and H2/hydrocarbon ratio of 6 1. A Cg naphthene concentration of... 

In the above three processes, the catalysts are all composed of Cu-based methanol synthesis catalyst and methanol dehydration catalyst of AI2O3. The reactors used by JFE and APCI are slurry bubble column, while a circulating slurry bed reactor was used in the pilot plant in Chongqing. It can be foxmd from Table 1 that conversion of CO obtained in the circulating slurry bed reactor developed by Tsinghua University is obvious higher and the operation conditions are milder than the others. 

It has been suggested that a pilot plant operation to determine the feasibility of developing this process be carried out in a tubular flow reactor with a volume of 0.15 m3. It is suggested that the reactor operate at 450 °C and 1 atm with a feed flow rate of 41.7 moles of pure tetra-chloroethane per kilosecond. Will the catalyst be susceptible to poisoning under these operating conditions ... 

Normally, the best activities observed during the development process are found for catalysts prepared in the laboratory where special attention is paid to each preparation step and where better control of e.g. impregnation and calcination temperature history can be achieved. This should be kept in mind when comparing activities of new lab-prepared catalysts with standard products from a production facility. As a consequence, it is seldom worth the effort to continue with a test production if the activity of the lab-prepared catalyst fails to meet the requirements. Important results for the test-produced catalysts are activity measurements covering the full range of operating conditions in the industrial converter and the mechanical strength. 

Present catalysts are developed for process plant service where transient conditions are not a concern. Typical shift catalysts, such as copper-zinc oxide, are reduced in place and must be isolated from air. There is a need for smaller, high surface area catalyst beads on low-density monolith substrate to be developed without reducing activity. This need applies to all fuel processor catalyst, not just the shift catalysts. There is also a need to demonstrate that the low-temperature, PROX catalysts have high selectivity toward CO and long term stability under operating conditions. 

Novel Processing Schemes Various separators have been proposed to separate the hydrogen-rich fuel in the reformate for cell use or to remove harmful species. At present, the separators are expensive, brittle, require large pressure differential, and are attacked by some hydrocarbons. There is a need to develop thinner, lower pressure drop, low cost membranes that can withstand separation from their support structure under changing thermal loads. Plasma reactors offer independence of reaction chemistry and optimum operating conditions that can be maintained over a wide range of feed rates and H2 composition. These processors have no catalyst and are compact. However, they are preliminary and have only been tested at a laboratory scale. 

I PA could always be made by direct hydration, but the severe operating conditions (high pressures and temperatures) and puny yields had always limited the economic enthusiasm for the process. Then catalysis research paid off with the development of a sulfonated polystyrene cationic exchange resin catalyst, a mouthful in itself. The breakthrough permitted reduced pressures and temperatures without loss of yield. The catalyst works in the vapor phase, the liquid phase, and the mixed phase. 

In 1986, BP Chemicals became the owners of the Monsanto technology. They subsequently also developed their own Cativa process, aimounced in 1996, carbonylation of MeOH to AcOH catalysed by Ir and Mel and promoted with specific metal iodides [8]. As with the improvements in the original Monsanto Rh process, Cativa had benefits such as improved catalyst stability and more favorable operating conditions [9]. 

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