Hydrogen Balance in Gas Streams

The hydrogen balance in gas streams was performed with the amount of hydrogen entering and leaving the reactor as well as the amounts of hydrogen dissolved in the 

The amount of dissolved hydrogen for all fractions was relatively low because the conditions at storage container of HDT liquid product are close to ambient and the solubility of hydrogen is strongly dependent on pressure and temperature. The value of hydrogen dissolved in the hydrotreated liquid stream was not obtained experimentally, but only by using two different correlations the detailed calculation was not considered appropriate to be included in this manuscript. 

Correlations of Lee and Stratiev-Tzingov were used to estimate the hydrogen consumption from the properties of liquid streams entering and leaving the reactor. These correlations, which are similar and dependent on feedstock and product properties, were developed for HDT of light gas oils. 

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Figure 12.9 shows for all the hydrotreated fractions the hydrogen consumption obtained from hydrogen balance in gas streams, the dissolved hydrogen from correlations, and calculations using the Hysys simulator. 

The purge gas from a petrochemical process is at 25°C and contains a mole fraction of methane of 0.6, the balance being hydrogen. This purge gas is to be burnt in a furnace to provide heat to a process with a cold stream pinch temperature of 150°C (A= 50°C). Ambient temperature is 10°C. 

Select Analytical Method In order to calculate the mass balances necessary for data evaluation, the concentration of the incoming and outgoing ozone gas stream as well as the liquid concentration of ozone and/or hydrogen peroxide must be measured. In case of U V-radiation the amount of photons should be measured by actinometry. 

An initial assumption is made that the tail-gas stream is composed of nitrogen only. By an elemental nitrogen balance, the first estimate for the flowrate of the tail-gas stream is made. This enables the mass (and then moles) of hydrogen in the tail-gasstream to bedetermined. A mole balance on elemental hydrogen determines the moles of hydrogen added in the make-up water. This figure is used to determine the unknown feed stream of make-up water. Hence, all feed streams are defined. 

Figure 12.19 shows a simplified process flow diagram of the LPMEOH demonstration facility in Kingsport. Three different feed gas streams (hydrogen, carbon monoxide, and the primary syngas feed known as balanced gas) are diverted from... 

In a first step of optimization, a set of 51 catalyst precursors were screened for their activity in WGS reaction at 120 C at ambient pressure and a model gas stream consisting of 10% carbon monoxide, 20% water vapor, and the balance nitrogen [59]. It is worth mentioning that the absence of reaction products such as hydrogen or carbon dioxide clearly influences the activity, but in this first phase a simple system was chosen. 

In the present illustration we use the gas scrubber as a vehicle to demonstrate the genesis of steady-state integral and differential balances. Four such balances are shown in Figure 2.4, with the balance space indicated by an envelope drawn around it. Solvent enters the envelope with a flow rate (kg solvent/s) and a solute concentration X2 (kg solute/kg solvent) and leaves with the same solvent flow rate but an increased concentration Xj. For the gas stream, the corresponding quantities are (kg carrier gas/s) and Y2, Yi in units of kg solute/kg carrier gas. The term carrier denotes the gaseous component, which is not absorbed by the solvent. Typically, that component is air or some other inert gas, such as hydrogen or nitrogen. 

In order to mitigate such conditions, the anode side hydrogen gas stream is often humidified to some extent and a higher pressure condition is maintained in the cathode side than the anode side. Overall transport and balance of water within the membrane is, therefore, controlled by a number of transport processes as discussed in Chapter 7. As a consequence, water management within the membrane is a critical issue for effective performance of the membrane and for the design of PEMFC. In addition to Nation-115 and -117, DuPont s Nation membranes are available in different thicknesses such as Nation-1135 and Nation-1110 with thicknesses of 89 pm and 254 pm, respectively. 

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