Velocity liquid hourly space

LHSV (liquid hourly space velocity) = (volume of liquid feed at 60°F/h)/(fF of reactor) = SCFH hquid feed/fF. 

The reactor feed may be preheated and the feed pressure may alter. The volumetric flowrate of gases depends on the reactor temperature and pressure at fixed mass flowrate. In many cases, the feed is liquid at room temperature, while the reaction mixture is a gas at the higher temperature in the reactor. In these instances, the performance of the reactor is represented as conversion and selectivity against the liquid hourly space velocity (LHSV). This is defined as... 

Normally, catalytic reformers operate at approximately 500-525°C and 100-300 psig, and a liquid hourly space velocity range of 2-4 hr" Liquid hourly space velocity (LHSV) is an important operation parameter expressed as the volume of hydrocarbon feed per hour per unit volume of the catalyst. Operating at lower LHSV gives the feed more contact with the catalyst. 

Figure 9-5. Effect of temperature and liquid hourly space velocity on conversion. ...

A vapor phase process for deparaffmization of light gas oils performed by the BP works in this way The gas oil, boiling range 230-320°C, is passed over a 5-A molecular sieve at 320°C and a pressure of 3.6 bar. The space velocity is 0.63 vol liquid gas oil per vol molecular sieve and per hour, [liquid hourly space velocity (lhsv) = 0.63] the adsorption period takes 6 min. Together with the gas oil vapor 120 vol N2 per vol liquid gas oil is led over the sieve as carrier and purge gas. After the adsorption period the loaded molecular sieve is purged at the same temperature with pure N2 for 6 min. Subsequently, the adsorbed /z-alkanes are desorbed by 1 vol liquid /z-pentane per vol molecular sieve and per hour. The /z-pentane is recovered from the /z-alkane//z-pentane mixture by simple distillation [15]. The IsoSiv process of the Union Carbide Corporation works in a similar way [16]. The purity of the isolated /z-alkanes is >98%. 

The catalytic tests [temperature = 543-703 K liquid hourly space velocity (LHSV) = 2,0 h gas hotuly space velocity (GHSV) (if not differently reported) = 510 h PYC/formaldehyde acetal =1 1 moEmol were carried out in... 

VGO hydrocracking is typically carried out at temperatures of 260-480°C, total pressure between 500-3000 psig, and liquid hourly space velocity ranging form 0.5 to 4h 1, leading to hydrogen consumption of 170-340 Nm3/m. ... 

Hydrodearomatization (HDA) was investigated on the mentioned catalysts in temperature range 260-360°C, at total pressures 35-80 bar, hydrogen to hydrocarbon ratios (H2/HC thereafter) 200-1000 Nm3/m3 and liquid hourly space velocity (thereafter LHSV) 0.75-4.0 h"1. The experiments were carried out on catalysts of steady-state activity, in continuous operation. 

LHSV liquid-hourly space velocity (m lefill/(m ata yst h))... 

A West Texas gas oil is cracked in a tubular reactor packed with silica-alumina cracking catalyst. The liquid feed mw = 0.255) is vaporized, heated, enters the reactor at 630°C and 1 atm, and with adequate temperature control stays close to this temperature within the reactor. The cracking reaction follows first-order kinetics and gives a variety of products with mean molecular weight mw = 0.070. Half the feed is cracked for a feed rate of 60 m liquid/m reactor hr. In the industry this measure of feed rate is called the liquid hourly space velocity. Thus LHSV = 60 hr Find the first-order rate constants k and k " for this cracking reaction. 

Hydrogenation To an up-flow tubular reactor packed with a supported Ni catalyst were fed a liquid stream comprised of 3.52 g/min of hydroformylated soy methyl ester and a recycle stream of 16.5 g/min (total liquid hourly space velocity of 3.65 hr ). Hydrogen was fed at 2000 seem, at 159 C and a reactor outlet pressure of 459, yielding the desired conversion of residual unsaturation and aldehydes. 

Space Velocity The volume or weight of a gas or liquid which flows through a catalyst bed or reaction zone per unit time divided by the volume or weight of catalyst. The terms liquid hourly space velocity (LHS V), and weight hourly space velocity (WHS V), are used to describe this type of flow measurement. High values correspond to short reaction times. 

Noble Metal Catalysts. Rh-based catalysts have been investigated on different supports, resulting in different H2 and CO yields. Gasoline and naphtha POX over a supported Rh catalyst were reported by Fujitani et al. For y-alumina supported Rh catalyst, maximum yields of 96% of both H2 and CO were reported with 0.2 wt% Rh loading at 700°C, an air equivalence ratio of 0.41, and a liquid hourly space velocity (LHSV) of 2 h A 0.05 wt% Rh supported on zirconia yielded 98% H2 and 85% CO at 725°C, an... 

Note Typically in reformer design, liquid hourly space velocity (LHSV) is defined as fresh liquid charge volumetric flow rate divided by catalyst volume. Catalyst volume includes the void fraction and is defined by WJpp( — e).]... 

Experimental conditions were 727, 756, and 794 K isothermal reactor temperature 827-, 1220-, and 2619-kPa hydrogen pressure 138- and 345-kPa hydrocarbon pressure and 1 to 26 liquid hourly space velocity. (See Section II for definition.) Charge stocks consisted of three C6 component blends (blends included 53/19/23/5, 25/75/0/0, and 0/0/50/50 wt. % hexane/methylcyclopentane/cyclohexane/benzene), C6 to C7 component naphthas (322-366 K TBP Kirkuk, Mid-Continent, and Nigerian), a C6 to C8 component naphtha (322-416 K TBP Mid-Continent), and C6 to C12 component naphthas (322-461 K TBP Arab Light, Mid-Continent, and... 

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. 

F., 300-lb./sq. in. gauge liquid hourly space velocity = 3, H2/hydro-carbon = 4. 

Terpene catalytic hydrodesulfurization was performed in a pilot-plant reactor at 200°C, 1 atm. The volume of catalyst was 70 cm the liquid hourly space velocity of terpene 0.4 h"1 and the hydrogen to terpene molar ratio of 7. The catalysts were pretreated in situ in a flow of N2 at 260°C then sulfided in H2S/H2 (1 9) from 260°C to 370°C. After 5 h-on-stream, the catalysts were cooled down to the reaction temperature in H2S/H2. The hydrocarbons were analyzed by GC on a CP Wax 57 CB capillary column at 65°C and the sulfur contents were determined by microcoulometry using the ASTM D312077 norm. The... 

Kazanskii and co-workers have described an interesting special case, double cyclization of -octane at 310°C over platinum-on-charcoal catalyst at 0.2 liquid hourly space velocity. The reaction product contains about 0.25% m-octahydropentalane and 2.2-4.5% alkylcyclopentanes (an approximately l lmixture of trans-l-methyl-2-ethylcyclopentane and n-pro-pylcyclopentane) (39, 40). Indirect evidence suggests that most of the octahydropentalane is formed from l-methyl-2-ethylcyclopentane, which cyclizes significantly faster than w-propylcyclopentane. 

This reaction was first observed by Plate, Erivanskaya, and Khalima-Mansur over platinum-on-carbon and platinum-on-alumina catalysts (43-48). Platinum-on-carbon catalyzes this reaction between 310°C and 390°C (above which the catalyst is poisoned) (44). Over an acidic platinum-alumina catalyst containing 0.5 wt% platinum and 0.1 wt% sodium, 16.7% acenaphthenes and 1.5% acenaphthylene are obtained at 460°C and at 0.4 liquid hourly space velocity in hydrogen diluent. Conversions are considerably lower in helium. 

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