Methane composition

Figure 6.110 gives responses to changes in the setpoint of the methane composition controller. At 0.1 h, it is reduced from 24 to 20 mol% methane. The vent flowrate increases sharply and ends up at a higher steady-state value. Synthesis gas feed and product flows both increase. The temperature of the coolant in the first reactor decreases because the increase in the reaction rate requires more heat removal. 

Figure 6.110 Changes in methane composition controller setpoint.

Step 9. The basic regulatory strategy has now been established (Fig. 10.2). We have some freedom to select several controller setpoints to optimize economics and plant performance. If reactor inlet temperature sets production rate, the setpoint of the total toluene flow controller can be selected to optimize reactor yield. However, there is an upper limit on this toluene flow to maintain at least a 5 1 hydrogen-to-aromatic ratio in the reactor feed since hydrogen recycle rate is maximized. The setpoint for the methane composition controller in the gas recycle loop must balance the trade-off between yield loss and reactor performance. Reflux flows to the stabilizer, product, and recycle columns must be determined on the basis of column energy requirements and potential yield losses of benzene (in the overhead of the stabilizer and recycle columns) and toluene (in the base of the recycle column). Since the separations are easy, in this system economics indicate that the reflux flows would probably be constant. 

The percent-methane compositions from the auger hole surveys conducted over the Sacramento and San Joaquin Basins are plotted in Fig. 5-21. There is a decrease from 98% methane in the north of the Sacramento basin to 90% in the south part, whilst the soil gas over the San Joaquin Basin has 82% methane. These data imply that a soil-gas grid would have defined local differences regionally. Furthermore these geochemical data are repeatable (Table 5-Xl) the percent-methane values on Fig. 5-21 were all determined at least two or three times over a three-year period and found to be repeatable. Compositional data have remained repeatable throughout our experience with soil-gas surveys. 

Synthesis of ammonia in a packed bed, catalytic reactor Steam reforming of methane Composition Temperature 100-fold increase in nitrogen conversion >95% H2 and less than 30 ppm CO with a dolomite CO2 acceptor... 

Again the program VLMU will be used with the critical properties in Table 4.6-1 and the value k12 = 0.055 given in Table 7.4-1. The only question is how to use the program to get K values. I have used the isothermal flash, since that is the only option that allows me to specify T and P. One then has to choose a feed composition that assures that one is in the two-phase region (this can be checked by a collection of bubble point or similar calculations, if desired). This corresponds to methane compositions in the range... 

Figure 4 The deactivation of a PdK Al20 + Th02) catalytic bead by HMDS and the subsequent recovery of catalytic activity. Temperature 800K. o—o, Oxidation of methane (composition of reactant mixture 2.5 mol% CH4, 20.5 mol% O2, together with 2.5 x lOr moP/o HMDS during deactivation experiments, balance N2). —, Oxidation of butane (composition of reactant mixture 0.75 moP/o C4H10,20.9 moP/o O2, together with 2.5 x 10" nwl% HMDS during deactivation experiments, balance N2)...

Prediction facing the problems of inconsistency during the process of the release of excess methane, methane composition and coal seam methane, could we find the source of the methane by taking it from projecting the microscopic molecular... 

CH4/O2/N2 (1/4/95 vol.-%). Nevertheless, it is characteristic of metallic palladium [11] when the catalyst is treated by CH4/N2 (1%) and show an intermediate state when it is treated by CH4/O2/N2 (2/4/94 vol.-%) or CH4/O2/N2 (1/1/98 vol.-%) gaseous mixtures (see Table 1). These resuhs show that the catalyst is oxidised under catalytic mixture, rich in oxygen and partially reduced under a stoechiometric or a rich methane composition. In addition, the catalyst can be reduced when it is treated by CH4/N2 (1%) at 400°C. 

My heart raced and my hands went cold as I thumbed through the recent gas chromatographic analysis of the FCCU wet gas. To my dismay the data confirmed my worst fear The hydrogen content of the wet gas had risen from 9% to 19% in just one week Here was the reason that the compressor had been forced into surge. The tremendous increase in hydrogen content and a lesser increase in methane composition had lowered the molecular weight of the wet gas from 34 to 29. 

Several cases were simulated to show the effects of catalyst activity. Plots of key operating conditions illustrate many effects that are uimoticed if only outlet compositions are examined. Table C. 1 shows how insensitive the outlet conditions are to catalyst activity, over a wide range. The plot of methane composition as a function of tube length for these cases is much more revealing. The methane compositions for all the cases approach similar values near the tube outlet, but the methane composition profiles are significantly different at positions closer to the inlet. 

Methane Composition Profile as a Function of Catalyst Activity... 

Table 3 shows results obtained from a five-component, isothermal flash calculation. In this system there are two condensable components (acetone and benzene) and three noncondensable components (hydrogen, carbon monoxide, and methane). Henry s constants for each of the noncondensables were obtained from Equations (18-22) the simplifying assumption for dilute solutions [Equation (17)] was also used for each of the noncondensables. Activity coefficients for both condensable components were calculated with the UNIQUAC equation. For that calculation, all liquid-phase composition variables are on a solute-free basis the only required binary parameters are those for the acetone-benzene system. While no experimental data are available for comparison, the calculated results are probably reliable because all simplifying assumptions are reasonable the... 

Given the assumptions, estimate the composition of the reactor effluent for fraction of methane in the recycle and purge of 0.4. 

The volume fraction would typically be used to represent the make up of a gas at a particular stage in a process line and describes gas composition e.g. 70% methane and 30% Ethane (also known as mol fractions) at a particular temperature and pressure. Gas composition may also be expressed in mass terms by multiplying the fractions by the corresponding molecular weight. 

The composition of natural gas varies oonsiderably from lean non-associated gas which is predominantly methane to rich associated gas containing significant proportion of natural gas liquids. Natural gas liquids (NGLs) are those components remaining once methane and all non-hydrocarbon components have been removed, i.e. (Cg-C ). 

Prior to methanation, the gas product from the gasifier must be thoroughly purified, especially from sulfur compounds the precursors of which are widespread throughout coal (23) (see Sulfurremoval and recovery). Moreover, the composition of the gas must be adjusted, if required, to contain three parts hydrogen to one part carbon monoxide to fit the stoichiometry of methane production. This is accompHshed by appHcation of a catalytic water gas shift reaction. 

Cmde gas leaves from the top of the gasifier at 288—593°C depending on the type of coal used. The composition of gas also depends on the type of coal and is notable for the relatively high methane content when contrasted to gases produced at lower pressures or higher temperatures. These gas products can be used as produced for electric power production or can be treated to remove carbon dioxide and hydrocarbons to provide synthesis gas for ammonia, methanol, and synthetic oil production. The gas is made suitable for methanation, to produce synthetic natural gas, by a partial shift and carbon dioxide and sulfur removal. 

The composition of the cracked gas with methane and naphtha and the plant feed and energy requirements are given in Table 9. The overall yield of acetylene based on methane is about 24% (14). A single burner with methane produces 25 t/d and with naphtha or LPG produces 30 t/d. The acetylene is purified by means of /V-methy1pyrro1idinone. 

The cracked gas composition is shown ia Table 10 for the water queach operatioa (16). Oae thousand cubic meters of methane and 600 m of oxygen produce 1800 m of cracked gas. If a naphtha quench is used, additional yields are produced, consuming 130 kg of naphtha/1000 of methane... 

Methane, ethane, and propane are the first three members of the alkane hydrocarbon series having the composition, Selected properties of these... 

The main commercial source of methane, ethane, and propane is natural gas, which is found ia many areas of the world ia porous reservoirs they are associated either with cmde oil (associated gas) or ia gas reservoirs ia which no oil is present (nonassociated gas). These gases are basic raw materials for the organic chemical industry as well as sources of energy. The composition of natural gas varies widely but the principal hydrocarbon usually is methane (see Gas, natural). Compositions of typical natural gases are Hsted ia Table 2. 

High temperature steam cools and eventually condenses as it propagates through the oil reservoir. To maintain foam strength as the steam cools, a noncondensible gas, usually nitrogen or methane, is often added to the injectant composition (196). Methods of calculating the optimum amount of noncondensible gas to use are available (197). 

Synthesis Gas Preparation Processes. Synthesis gas for ammonia production consists of hydrogen and nitrogen in about a three to one mole ratio, residual methane, argon introduced with the process air, and traces of carbon oxides. There are several processes available for synthesis gas generation and each is characterized by the specific feedstock used. A typical synthesis gas composition by volume is hydrogen, 73.65% nitrogen, 24.55% methane, <1 ppm-0.8% argon, 100 ppm—0.34% carbon oxides, 2—10 ppm and water vapor, 0.1 ppm. 

The equihbrium composition of the product gas can be altered by choice of suitable temperature, pressure, and steam to feedstock ratio to produce a gas mixture consisting largely of methane or largely of hydrogen having varying proportions of carbon monoxide (qv). In each case, some carbon dioxide (qv)... 

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