Slurry phase operation

In this study, the influence of dispersion and distribution of the active phase (rnthenium) and the accessibility and performance of the carbon-based monolithic strnctures have been evaluated in the hydrogenation of D-glucose. Special attention has been paid to the stabihty of the catalysts in successive hydrogenation rnns. Especially, fixed-bed catalysts (e.g., monoliths) require a maintained activity for long periods of time for successful application in industry. The performance of the monolithic reactor has been compared with slurry-phase operation. 

In recent years, catalysts have been developed which give a non-Schulz-Flory product distribution in fixed beds. Such catalysts should be tested in slurry phase operation. 

Eastman Chemical Company has operated a coal-to-methanol plant in Kingsport, Tennessee, since 1983. Two Texaco gasifiers (one is a backup) process 34 Mg/h (37 US ton/h) of coal to synthesis gas. The synthesis gas is converted to methanol by use of ICl methanol technology. Methanol is an intermediate for producing methyl acetate and acetic acid. The plant produces about 225 Gg/a (250,000 US ton/a) of acetic anhydride. As part of the DOE Clean Coal Technology Program, Air Products and Cnemicals, Inc., and Eastman Chemic Company are constructing a 9.8-Mg/h (260-US ton/d) slurry-phase reactor for the conversion of synthesis gas to methanol and dimethyl... 

Bubble columns and mechanically stirred reactors are the most common reactor types for slurry systems in laboratories, but they have many disadvantages from an industrialization perspective. Mechanically stirred reactors usually used for laboratorial studies are difficult to scale-up. In order to achieve good mixing and mass transfer between the gas and slurry phases, bubble column must be operated at a high space velocity, which leads to a relative low one-through conversion of the syngas. 

Another recent new application of a microporous materials in oil refining is the use of zeolite beta as a solid acid system for paraffin alkylation [3]. This zeolite based catalyst, which is operated in a slurry phase reactor, also contains small amounts of Pt or Pd to facilitate catalyst regeneration. Although promising, this novel solid acid catalyst system, has not as yet been applied commercially. 

Srivastava [434,435], The process can be carried out under aerobic (KSARC56) or anaerobic conditions (Mic-1). The identified products include methane, lower alcohols, volatile fatty acids, and/or humic acid. For aromatic feeds the main products are phenols (and derivatives), methane and carbon dioxide. The process is carried out in a slurry phase, at pH of 7.8, under moderate stirring using a bacteria concentration less than 20%. The feed concentration could not exceed more than 50%, as stated in the patent document. In the aerobic operation, the thermophilic consortium KSARC56 is operated for 48 hours at a temperature of up to about 60°C. For the anaerobic operation a mixture of N2 C02 of about 80 20 was used. 

SSPD [Sasol slurry phase distillate] A process for converting natural gas to diesel fuel, kerosene, and naphtha. Operated by Sasol in South Africa since 1993. Three stages are involved. In the first, natural gas is converted to synthesis gas by reforming. In the second, the synthesis gas is converted to waxy hydrocarbons in a slurry-phase reactor. In the third, the waxes are upgraded to middle distillates. See also Arge. 

Qatar Sasol and Qatar Petroleum, in alliance with Chevron Sasol s slurry phase technology 34000 2005 (2 other F-T plants are scheduled to operate in the coming years with the second F-T plant having a scale of 65 000 bpd)... 

The rate-controlling step in slurry reactor operation is often desorption of contaminants from soil particles (equation 1.2). Assuming that biodegradation occurs in the aqueous phase, the rate of disappearance of a contaminant in the aqueous phase can be expressed as (Luthy et al., 1994) ... 

Compeau et al. (1990) reported a full-scale slurry-phase PCP remediation. The system consisted of soil washing and screening and resulted in clean soil and wash solution. The wash solution was a slurry containing PCP and < 60-mesh-size soil particles at approximately 20% solids concentration. Slurry was treated subsequently in on-site slurry-phase bioreactors. A 50 m3 slurry reactor was operated in batch mode and inoculated by an uncharacterized PCP-mineralizing culture (107 cells/ml of slurry). After 14 days, 370mg PCP/kg slurry had been degraded to below 0.5 mg/kg. For effective biogradation to occur, inoculation was required. 

Bubble slurry column reactors (BSCR) and mechanically stirred slurry reactors (MSSR) are particular types of slurry catalytic reactors (Fig. 5.3-1), where the fine particles of solid catalyst are suspended in the liquid phase by a gas dispersed in the form of bubbles or by the agitator. The mixing of the slurry phase (solid and liquid) is also due to the gas flow. BSCR may be operated in batch or continuous modes. In contrast, MSSR are operated batchwise with gas recirculation. 

Monoliths exhibit a large flexibility in operation. They are well suited for optimal semibatch, batch, continuous, and transient processing. Catalytic conversion can be combined with in situ separation, catalytic reactions can be combined, heat integration is possible, and all lead to process intensification. In the short term, catalytic monoliths will be applied to replace trickle-bed reactor and slurry-phase... 

Fischer-Tropsch Technology FTS can be carried out in several different reactor types fixed bed, fluidized bed, or slurry phase and at different temperatures. The high-temperature Fischer-Tropsch (HTFT) synthesis runs at 320°C-350°C, at which temperatures typically all products are in the gas phase [22], HTFT is operated in fluidized-bed reactors, with iron catalysts. Selectivities correspond to chain-growth probabilities in the range of 0.70-0.75 and are ideal for gasoline production, but olefins and oxygenates are formed as well and are used as chemicals. 

The above described reactor is useful for the measurements of heat of reaction as well as thermal behavior of gas-liquid or gas- liquid-solid, high-pressure, high-temperature reactions. Since the reactor can be operated under adiabatic conditions, it simulates the commercial operation. The reactor was successfully utilized by Bhattacharjee et al. (1986) for investigating thermal behavior of slurry phase, catalytic synthesis gas conversion. 

As part of the work undertaken by APCI under contract to the DOE, to develop a slurry phase Fischer-Tropsch process to produce selectively transportation fuels, a study of the hydrodynamics of three phase bubble column reactors was begun using cold flow modelling techniques (l ). Part of this study includes the measurement of solid concentration profiles over a range of independent column operating values. 

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