Pilot plant scheme

Figure 2. Photocatalytic Pilot Plant scheme (recirculating mode is shown).

After development of a new process scheme at laboratory scale, constmction and operation of pilot-plant faciUties to confirm scale-up information often require two or three years. An additional two to three years is commonly required for final design, fabrication of special equipment, and constmction of the plant. Thus, projections of raw material costs and availabiUty five to ten years into the future become important in adopting any new process significantly different from the current technology. 

Coal Liquefaction at Wilsonville. Starting ia 1974 the Advanced Coal Liquefaction R D Facihty at WilsonviUe, Alabama operated a 6 t/d pilot plant and studied various coal Hquefaction processiag schemes. The facihty, cosponsored by the DOE, the Electric Power Research Institute (EPRI) and Amoco Oil Co, was shut down ia early 1992. 

Review of coal Hquefaction research may be found ia References 1—3. Hereia, those processiag schemes for coal Hquefactioa that, siace the 1970s, have received atteatioa beyoad the laboratory to pilot plants or process development units are presented. 

Other variations of catalytic and noncatalytic coal Hquefaction schemes were also developed (27,28). Additionally, bench-scale and semiworks systems have been operated in Germany by researchers at Bergbau-Forschung in Essen (29). A 2.5 ton per day pilot plant is being operated by the National Coal Board in the United Kingdom at Point of Ayr in Wales (30). This facdity is notable for the use of semibatch or candle filters for removal of mineral matter and unreacted coal from the primary Hquefaction products. 

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. 

The scheme of commercial methane synthesis includes a multistage reaction system and recycle of product gas. Adiabatic reactors connected with waste heat boilers are used to remove the heat in the form of high pressure steam. In designing the pilot plants, major emphasis was placed on the design of the catalytic reactor system. Thermodynamic parameters (composition of feed gas, temperature, temperature rise, pressure, etc.) as well as hydrodynamic parameters (bed depth, linear velocity, catalyst pellet size, etc.) are identical to those in a commercial methana-tion plant. This permits direct upscaling of test results to commercial size reactors because radial gradients are not present in an adiabatic shift reactor. 

At present, thermal catalysis induced by solar radiation is more ready for potential practical use in the energy production industry of the future, than photocatalysis [7,9,29,30], Fig.7 illustrates the scheme of the pilot plant for thermocatalytic solar-to-chemical energy... 

Fig.8. Pilot plant for solar energy conversion based on the scheme of Fig. 7.

The alkyl ketone candidates With definition of the finasteride manufacturing process came a new challenge. The most efficient synthesis of the second generation candidate would make use of the penultimate in the finasteride process 33 as starting material (Scheme 3.25). With a pilot plant campaign to make 3 scheduled, realizing this objective became a priority. None of the methods reported in the literature for ester to ketone conversion had been applied to a hindered steroidal C17 ester. 

On pilot plant scale, the reaction, shown in Scheme 3.26, gave a yield of 83% (cf. 86% laboratory yield). The overall yield for conversion from the acid 8 was improved from 40 to 75% by this route compared with the route through the acyl imidazohde. 

The ketone 15 was eventually prepared by Grignard addition to Weinreb amide 21, as shown in Scheme 5.5. The Weinreb amide 21 was prepared from p-iodobenzoic acid (20). The phenol of readily available 3-hydroxybenzaldehyde (22) was first protected with a benzyl group, then the aldehyde was converted to chloride 24 via alcohol 23 under standard conditions. Preparation of the Grignard reagent 25 from chloride 24 was initially problematic. A large proportion of the homo-coupling side product 26 was observed in THF. The use of a 3 1 mixture of toluene THF as the reaction solvent suppressed this side reaction [7]. The iodoketone 15 was isolated as a crystalline solid and this sequence was scaled up to pilot plant scale to make around 50 kg of 15. 

In order to overcome these problems, the flow schemes as shown in Figures 1 and 2 were developed. These incorporate the use of Kerr-McGee Corporation s Critical Solvent Deashing and Fractionation Process (CSD) for recovery of the SRC. The Kerr-McGee Process adds extra flexibility since this process can recover heavy solvent for recycle, which is not recoverable by vacuum distillation. EPRI contracted with Conoco Coal Development Company (CCDC) and Kerr-McGee Corporation in 1977-1978 to test these process concepts on continuous bench-scale units. A complementary effort would be made at the Wilsonville Pilot Plant under joint sponsorship by EPRI, DOE, and Kerr-McGee Corporation. This paper presents some of the initial findings. 

Process scheme of the supercritical water gasification pilot plant at FZ Karlsruhe. (Reproduced from Boukis, N., Galla, U., Diem, V., and Dinjus, E., Science in Thermal and Chemical Biomass Conversion, CPL Press, Victoria, 2004, 975-990. With permission.)... 

The reagent scheme used in the pilot plant included oxalic acid-acidified silicate Na2SiF6 gangue depressant system and collector composed of a mixture of phosphoric esters and alkyl sulphate modified with mineral oil. The metallurgical results obtained are presented in Table 23.5. 

A large portion of monazite production comes from mineral sand deposits. In the beneficiation of monazite from mineral sand deposits that contain garnet, ilmenite, shell and silicates, the physical concentration and combination of physical preconcentration-flotation is used. Several reagent schemes using flotation were developed throughout various studies [8-10] and some have been confirmed in continuous pilot plants. 

An interesting variety of the organization scheme is the combination of the positions of head of business development and R D in one and the same person. It eliminates the above mentioned friction. This structure is particularly suitable for small to midsize fine-chemical companies, where the total number of researches and business development managers does not exceed 10. The ideal candidate for this position is a scientist with several years of experience in industrial R D and pilot plant production, plus a commercial flair. 

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