CO-shift unit

The synthesis gas product from the Shell Gasification Process (SGP) unit is treated for sulfur removal in a Shell Sulfinol unit. The CO-Shift unit includes high-temperature shift cata-... 

CO-SHIFT UNIT, COg-REMOVAL UNIT AND METHANATION UNIT PRODUCT GAS COMPOSITIONS AND RATES... 

The Methanation unit consists of a catalyst bed contained in a reactor vessel, feed-to-product heat exchange, product cooling and a knock-out vessel for separating condensed water. Treated gas from the C02-Removal unit is also preheated by heat exchange in the CO-Shift unit to conserve energy. 

A reduction of steam-to-dry gas ratio in the CO-Shift unit to 1.2 1.0 mol/mol as discussed in the CO-Shift process description section would reduce the hydrogen cost by about 0.07/10° scf of H2 ... 

The bonding mode is dependent on the nature of the metal centre as well as the steric or electronic properties of the imido substituent. For example, the M(CO)5 unit in the (AO-trigonal complex [W(CO)5 S(NMe)2 ] undergoes a 1,3-shift between the two nitrogen donors, whereas the tert-butyl forms a N,N -chelated [W(CO)4 S(NtBu)2 ] complex, as is also observed with main-group metal halides, e.g., [SnCl4 E(NtBu)2 ] (E=S, Se).153... 

Now suppose we move counter-clockwise along the circle at a constant speed, which we will call co. co has units of radians per second, and is also called the angular velocity. The x- and j-coordinates will vary with time as shown in Figure 1.2. Notice that the waveform is the same for the cosine (x-coordinate) and the sine (y-coordinate) except for a shift of one-quarter cycle. The frequency of the sine wave, commonly denoted by the symbol v, is the number of cycles per second. This unit is given the special name of Hertz. Since there are 2n radians in one cycle, co = 27rv. One complete cycle requires a time T = 2jt/o> = 1/v, which we call the period of the sine wave (seconds per cycle). 

Since Texaco syngas process was not being used to make ammonia, some of the steps would have to be modified to apply it to ammonia production. A CO Shift step might be needed upstream of the C02 Removal unit the membrane unit might be replaced by a Pressure-Swing Absorption (PSA) unit and a methanation unit might be needed to remove residual CO and C02. 

Influence of the downstream plants. Up to now, we have regarded the coal gasification reactor with the waste heat recovery system as an isolated unit. In the event that the gas generated is intended to be used as fuel gas, for example in a combined power station, this approach is justified. If, however, the gas is to be used as synthesis gas, the effect of the downstream units must be taken into consideration. In such cases it is necessary to feed the gas to a CO shift conversion unit in order to obtain the C0/H2 ratio required for the synthesis process. Apart from gasification at atmospheric pressure, which requires an intermediate compression step, it has proved advisable to locate the CO shift conversion directly downstream of the gasification section. A stage in which dust particles are removed from the gas is situated between these two units. It is assumed that exergy losses do not occur in this unit. 

The principal methanation reactions, given below, illustrate why the purity and yield of hydrogen is influenced by the effectiveness of the CO-Shift and C02-Removal units. 

Estimated installed capital costs are shown in Table III and estimated operating costs are given in Figure 5 and Table IV for the production of hydrogen from heavy fuel oil by use of the SGP and Sulfinol units along with CO-Shift, C02-Removal and Methanation units. The design bases for the process economics case are described below. 

Shift unit—Reacts syngas CO and moisture (H2O) at a low temperature in the presence of a catalyst using the shift gas reaction (equation 1.4), forming H2 and CO2. 

Partia( oxidation CO shift-conversion Recfisoi scrubbing unit scrubbing box NH -loop... 

The impedance response of a resistor in parallel to a capacitor is shown in Figure 4.7 as a function of frequency / in units of Hz. When plotted as a function of frequency co in units of s ( e upper axis), the minimum in the imaginary part of the impedance appears clearly at a characteristic frequency of a c = 1/Tc- The dashed line corresponds to the characteristic frequency of 1 s. When plotted against frequency in units of Hertz, the characteristic frequency is shifted by a factor of 27T, i.e., fc = l2nXc. 

The formation of nickel and iron carbonyls can take place in the presence of gaseous carbon monoxide in contact with metallic nickel or iron or their sulphides. The thermodynamics favor this reaction at low temperatures so the formation takes place during gas cooling. The consequences of any metal carbonyl slip into the gas treatment units depend very much on the treatment scheme, since any subsequent reheating (e.g., for a CO Shift) will tend to decompose the carbonyls back to the metals or their sulfides. 

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