Processing conditions, pilot plant

When the pilot plant process is transferred to production the evaluation of the normal operating conditions has to be repeated to account for the changing parameters due to the scale up. Furthermore, the quantitative assessment of process consequences under deviating operating conditions must have been completed. 

Several pilot plant tests have been made with gas oil pyrolyzate and using Shell s proprietary catalyst in both Stages 1 and 2. Typical data from pilot plant processing of gasoline/ gas oil pyrolyzate under relatively severe conditions (i.e.,... 

The catalyst used for this reaction, as described in this paper, was Au-Pb/Al203 and the conditions used were 90°C and 0.1-5 MPa [74]. A pilot plant process demonstration, with a capacity of tons... 

Fluoroaliphatic Thermolytic Routes. The reaction of diduorocarbene (generated from CHCIF2 at 600°C) with cyclopentadiene to give duoroben2ene (70% yield) has been scaled up in a pilot-plant/semiworks faciUty (capacity = several dozen t/yr) (77,78). The same process can now be effected under Hquid-phase conditions in the presence of phase-transfer catalysts (79,80). 

Pilot plants are often more hazardous than process plants, even though they are smaller ia size, for many reasons. These iaclude a tendency to relax standard safety review procedures based on the small scale, exceptionally qualified personnel iavolved, and the experimental nature of the research operations the lack of estabhshed operational practice and experience lack of information regarding new materials or processes and lack of effective automatic iatedocks due to the frequendy changing nature of pilot-plant operations, the desire for wide latitude in operating conditions, and the lack of hill-time maintenance personnel. 

The pilot plant must also be carehiUy designed so that its control and safety systems are "fad-safe" and any unexpected equipment or utdity fadure brings the unit into a safe and de-energized condition. Unexpected or rapid process changes, if they can herald or lead to dangerous conditions (eg, mnaway exothermic reaction), should be continuously monitored by appropriate instmmentation and suitable automatic action provided (1,55—67). 

Specific reactor characteristics depend on the particular use of the reactor as a laboratory, pilot plant, or industrial unit. AH reactors have in common selected characteristics of four basic reactor types the weH-stirred batch reactor, the semibatch reactor, the continuous-flow stirred-tank reactor, and the tubular reactor (Fig. 1). A reactor may be represented by or modeled after one or a combination of these. SuitabHity of a model depends on the extent to which the impacts of the reactions, and thermal and transport processes, are predicted for conditions outside of the database used in developing the model (1-4). 

The depth of cut involved in precoat filtration is a veiy important economic factor. There is some disagreement as to the method required to accurately predic t the minimum permissible depth of cut. Some investigators maintain that the depth of cut can be evaluated only in a quah-tative manner during bench-scale tests by judging whether the process solids remain on the surface of the precoat beck This being so, they indicate that it is necessaiy to run a continuous pilot-plant test to determine the minimum permissible depth of cut. The use of a continuous pilot-plant filter is a veiy desirable approach and will provide accurate information under a variety of operating conditions. 

Isolation procedures for many biochemicals are based on chromatography. Practically any substance can be selected from a crude mixture and eluted at relatively high purity from a chromatographic column with the right combination of adsorbent, conditions, and eluant. For bench scale or for a small pilot plant, such chromatography has rendered alternate procedures such as electrophoresis nearly obsolete. Unfortunately, as size increases, dispersion in the column ruins resolution. To produce small amounts or up to tens of kilograms per year, chromatography is an excellent choice. When the scale-up problem is solved, these procedures should displace some of the conventional steps in the chemical process industries. 

Often pilot plant or research data for developing a process are obtained on a batch operation. Later, a continuous process will usually prove that smaller equipment can be used and that the operation. vill be more economical. Normally batch mixing requires 10%-25% more power than continuous [29] for stable conditions how ev-er, the reaction time for continuous flow is always longer than the reaction time for batch flow, but the practical result may show batch time cycle is increased by filling,... 

Consequently, two semicommercial pilot plants have been operated for 1.5 years. One plant, designed and erected by Lurgi and South African Coal, Oil, and Gas Corp. (SASOL), Sasolburg, South Africa, was operated as a sidestream plant to a commercial Fischer-Tropsch synthesis plant. Synthesis gas is produced in a commercial coal pressure gasification plant which includes Rectisol gas purification and shift conversion so the overall process scheme for producing SNG from coal could be demonstrated successfully. The other plant, a joint effort of Lurgi and El Paso Natural Gas Corp., was operated at the same time at Petrochemie Schwechat, near Vienna, Austria. Since the starting material was synthesis gas produced from naphtha, different reaction conditions from those of the SASOL plant have also been operated successfully. 

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. 

Collect together all the kinetic and thermodynamic data on the desired reaction and the side reactions. It is unlikely that much useful information will be gleaned from a literature search, as little is published in the open literature on commercially attractive processes. The kinetic data required for reactor design will normally be obtained from laboratory and pilot plant studies. Values will be needed for the rate of reaction over a range of operating conditions pressure, temperature, flow-rate and catalyst concentration. The design of experimental reactors and scale-up is discussed by Rase (1977). 

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