Velocity gas hourly space

To manufacture the lower aLkylamines by Method 1, ammonia and alcohol are passed continuously over a fixed bed containing the catalyst in a gas—soHd heterogeneous reaction. The ammonia to alcohol mole ratio varies from 2 1 to 6 1 depending on the amine desired as shown in Figure 1. Operating conditions are maintained in the range from 300—500°C and 790—3550 kPa (100—500 psig) at a gas hourly space velocity between 500—1500 vol/vol per hour. Yields are typically in excess of 90%. 

Both catalyst space velocity and bed geometry play a role. The gas hourly space velocity (GHSV) is used to relate the volumetric flow rate to the catalyst volume. GHSV has units of inverse hour and is defined as the volume flow rate per catalyst volume. 

GHSV (gas hourly space velocity) = (volumes of feed as gas at STP/h)/(vohime of reactor or its content of catalyst) = SCFH gas feed/fF. 

Another commonly used term is the gas hourly space velocity (GHSV), which is defined as... 

Room temperature CO oxidation has been investigated on a series of Au/metal oxide catalysts at conditions typical of spacecraft atmospheres CO = 50 ppm, COj = 7,000 ppm, H2O = 40% (RH) at 25 C, balance = air, and gas hourly space velocities of 7,000- 60,000 hr . The addition of Au increases the room temperature CO oxidation activity of the metal oxides dramatically. All the Au/metal oxides deactivate during the CO oxidation reaction, especially in the presence of CO in the feed. The stability of the Au/metal oxide catalysts decreases in the following order TiOj > FejO, > NiO > CO3O4. The stability appears to decrease with an increase in the basicity of the metal oxides. In situ FTIR of CO adsorption on Au/Ti02 at 25 C indicates the formation of adsorbed CO, carboxylate, and carbonate species on the catalyst surface. 

The reactions were carried out in the steady state flow mode as described previously [11]. Differential kinetics were determined from plots of conversion vs. W/F. Three catalysts CoZSM-5, HZSM-5 and NaZSM-5 (Si/AI = 11) were studied in this work. The catalyst preparation and the standard pretreatment used prior to reaction have been described previously [11]. It involved dehydration in flowing dried 0 as the temperature was raised slowly to 500°C. The feed comprised CH4 (0.28%), NO (0.21 %) or NOj (0.21 %). and/or Oj (2.6%) in He. The flow rate was 75 ml/min and the gas hour space velocity (GHSV) was varied between 4,500 and 250,000 h by changing the weight of catalyst samples. 

However, the detailed description of the FT product distribution together with the reactant conversion is a very important task for the industrial practice, being an essential prerequisite for the industrialization of the process. In this work, a detailed kinetic model developed for the FTS over a cobalt-based catalyst is presented that represents an evolution of the model published previously by some of us.10 Such a model has been obtained on the basis of experimental data collected in a fixed bed microreactor under conditions relevant to industrial operations (temperature, 210-235°C pressure, 8-25 bar H2/CO feed molar ratio, 1.8-2.7 gas hourly space velocity, (GHSV) 2,000-7,000 cm3 (STP)/h/gcatalyst), and it is able to predict at the same time both the CO and H2 conversions and the hydrocarbon distribution up to a carbon number of 49. The model does not presently include the formation of alcohols and C02, whose selectivity is very low in the FTS on cobalt-based catalysts. 

The most common descriptions of these quantities in industry are the gas hourly space velocity... 

The most common unit of <2rel is bed volumes per hour (BV/li). Space velocity is also used in catalytic reactors, especially in three-phase fixed-beds, and is referred to as liquid hourly space velocity (LHS V) for the liquid phase, and gas hourly space velocity (GHSV) for gas phase. As mentioned above, space-time and space velocity are measured under the entrance conditions. However, for space velocity, other conditions are frequently used (Fogler, 1999). For example, the LHSV is measured at 60 to 75 °F, and GHSV at standard temperature and pressure. 

The apparent gas hourly space velocity (SV) is defined at the standard temperature and pressure... 

Gas phase studies were performed at 0.1 MPa total pressure with a flow rate of loo cc/min H2 and loo cc/min He (Linde). The helium stream was diverted through a saturator containing the liquid reactant UAL (Aldrich) such that its volume fraction in the inlet to the reactor was 0.5%. The gas hourly space velocity was 120 lh g1 catalyst. Prior to reaction, the catalyst was pretreated at 673 K for at least 2 hours following a 1 K/min rise to the reduction temperature. The reactor was coaled under... 

To focus only on the binary compositions, the catalysts were evaluated under the following experimental conditions feed 40% propylene and 10% oxygen temperature, 250 °C and 20 000 h-1 of GHSV (gas hourly space velocity). Three different catalyst preparation procedures were used [40] ... 

Mass-related reaction rates, tm, were determined at normal pressure for the following ranges of operating conditions T = 473 to 503 K, xc6h12 = 2-6 vol%, normal pressure conditions at both membrane sides, gas hourly space velocity (GHSV) 400-1000 h-1. The composition of the effluent was measured under steady-state conditions using gas chromatography (GC). 

---