Loop-type reactors

The catalysts most frequently used are based on noble metals (mainly palladium and platinum) on various supports, or on nickel catalysts (mainly Raney type). Hydrogenations are generally performed in the liquid phase, under relatively mild conditions of temperature and pressure (1—40 bar). Most processes are performed batch-wise using powder catalysts in stirred tank or loop-type reactors with sizes up to 10 m . 

In the process, homopolymer and random copolymer polymerization occurs in the loop-type reactor (or vessel-type reactor) (1). For impact copolymer production, copolymerization is performed in a gas-phase reactor (2) after homopolymerization. The polymer is discharged from a gas-phase reactor and transferred to the separator (3). Unreacted gas accompanying the polymer is removed by the separator and recycled to the reactor system. The polymer powder is then transferred to the dryer system (4) where remaining propylene is removed and recovered. The dry powder is pelletized by the pelletizing system (5) along with required stabilizers. 

H. Bockhorn et al. [43] HDPE, PP Closed loop-type reactor 410-480 Gas, oil... 

Most processes are performed batch-wise using powder catalysts in stirred tank or loop-type reactors with sizes up to 10 m ... 

Fast Breeder Test Reactor (FBTR) is a 40 MWt/ 13.2 MWe sodium cooled, mixed carbide fuelled, loop type reactor. It has two primary and secondary sodium loops and a common steam water circuit, which supplies high pressure, high temperature superheated steam to turbine generator (TG). Heat is rejected in cooling tower (Fig 1). A 100% capacity dump condenser is provided for reactor operation even when the TG is not in service. The mmn aim of the reactor is to generate experience in the design, construction and operation of sodium cooled fast reactors and to serve as an irradiation facility for the development of fuels and structural material for fast reactors. It achieved first criticality in Oct 85 with Mark I core... 

The fast breeder test reactor (FBTR) is a loop type reactor located at Kalpakkam, India. The reactor has been operated for 27 600 h till now at various power levels up to 17.4 MW(t). The peak bum up of 90 000 MW d/T was achieved in the 70% PuC + 30% UC Mark-I fuel. Turbo Generator was synchronized to the grid with the nuclear steam to check its performance. Continued operation of TG is planned at high power. The post irradiation examination of the... 

The gas mixture containing approximately 80vol% Hj is fed directly to the bioreactor. The CO2 gas is used as a carbon source for the bacteria. To achieve good mixing without introducing high shear forces, a gas-lift loop type reactor is used, as illustrated in Figure 4. The fresh H2 from the reformer is mixed with the recycle gas and is distributed over the riser surfaee of the reactor. A small amount of the gas recirculation flow is bled off to remove inert components (mainly N2). The gas bleed is used as fuel for the burner of the reformer system. 

Figure 7 - The Bio Gas-Lift Loop Type Reactor, Volume 500 m ...

FBTR is a 40 MWt/13.2 MWe, mixed carbide fuelled, sodium cooled, loop type reactor. It has been provided with two once through serpentine type steam generators (SG) in each of the two secondary loops. The reactor has 100% steam dump capacity, in order to continue reactor operation, when turbine generator (TG) is not available. The reactor achieved its first criticality in October 1985. Since then it has been operated at various power levels in stages upto 10.5 MWt. The small carbide core with 26 fuel subassemblies has been licensed to operate upto 10.5 MWt with 320 W/cm peak linear heat rating of fuel. All the works in TG system have been completed and the turbine has been rolled upto its synchronous speed of 3000 rpm. In March 1997, clearance from safety authorities has been obtained for further loading of the fuel subassemblies and to operate the reactor upto a power level 12.5 MWt. Synchronisation of TG with grid will be done shortly. 

JAPC conducted for the past several years conceptual design studies of the DFBR-1 in accordance with the basic policy of the Federation of Electric Power Companies (FEPC) and confirmed the feasibility of top entry loop type reactor. 

As for the demonstration fast breeder reactor (DFBR) of Japan, the Japan Atonaic Power Company (JAPC) conducted conceptual design studies for the past several years, and confirmed the feasibility of top entry loop type reactor concept. Based on results of the design studies, the Federation of Electric Power Companies (FEPC) decided in January 1994 to start construction of the DFBR plant at the beginning of the 2000 s. FEPC also decided the basic specifications of the DFBR plant. 

Various loop-type reactors, consisting of a circulation pump, homogeniser (where the acid is introduced in Ae circulating alkaline paste) and heat exchanger, are used for the complex neutralisation step. 

A simplified modular design approach is applied to all SMART primary components. The optimized and modularized small-sized components allow for easy factory fabrication and direct installation at the site, which leads to the shortening of an overall construction time and schedule. These features are to ensure the construction period of less than three years from the first concrete to fuel load. The compact and integral primary system also eliminates the complexity and extra components associated with conventional loop-type reactors. 

LOOP-TYPE REACTOR RUTA-70 FOR NUCLEAR DISTRICT HEATING PLANT... 

Readman, J.E., Olafsen, A., Earring, Y., and Blom, R. (2005) Lao,8Sro,2Coo,2Feo,803 a as a potential oxygen carrier in a chemical looping type reactor, an in-situ powder X-ray difiraction study. /. Mater. Chem., 15, 1931-1937. 

Especially in a loop-type reactor, the behaviour of the pipe work is of significant importance. Tests showed the following ... 

Natural circulation DHR experiments u g the eiq)erimental fast reactor Joyo [5.42], The tests are intended to demonstrate the natural convection DHR capability of Joyo and serve as a basis for the confirmation of similar but larger loop-type reactors. 

In the preliminary conceptual design phase from 1990 to 1991, the technical feasibility of the top entry loop type reactor was confirmed and the possibility of FBR commercialization was also envisioned The conceptual design study of the DFBR was conducted for two years from 1992 The design of the DFBR is summarized below, along with the technical and cost evaluation results... 

Reactor type Top entry loop type reactor... 

Thermal hytt-aulics. Three kinds of thermal hydraulic tests were conducted to confirm the technical feaability of the top entry loop type reactor a natural circulation flow test, a multiple-surface sloshing test and a gas entrainment test. These tests were conducted with the cooperation of CRDEPI, PNC and various universities. 

FIG V-3. Visualization of a threshold effect on the overnight cost. Table V-1 presents the calculations of costs performed with the CEA SEMER code developed for the economic evaluation of nuclear plants [V-3]. A comparison of calculations is made between two sites with the same electrical power the first, with large classical PWRs, the second, with SCOR reactors. This cost assessment is performed with nomenclature recommended by the IAEA. TABLE V-1. ECONOMIC AS SES SMENT - COMPARISON BETWEEN A LARGE LOOP-TYPE REACTOR AND SCOR (RELATIVE UNITS) ... 

The simplification of the nuclear buildings, reduction in components and the elimination of welding between large components reduces the construction duration to 3 years instead of 6 years, for a classical large loop-type reactor. This leads to a gain of 17 points compared to a reactor (classical PWR or SCOR) with 6-year construction duration. 

A large size (600—1500 MWei) loop-type reactor with mixed uranium—plutonium oxide fuel and potentially minor actinides, supported by a fuel cycle based upon advanced aqueous processing at a central location serving a number of reactors ... 

Table 5.2 Pool- and loop-type reactors in the world...

MONJU is a loop type reactor. The primary pipe, which is below the level of the system sodium, is located in the guard vessel whose function is to ensure the adequate sodium level. The leak-before-break (LBB) principle has been demonstrated for this design. Hence, the DEGR is not considered as DBE. 

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