Gas dean

The use of hot gas dean-up methods to remove the sulfur and particulates from the gasified fud increases turbine performance by a few percentage points over the cold clean-up systems. Hot gas dean-up permits use of the sensible heat and enables retention of the carbon dioxide and water vapor in the... 

Luster MJ, Boorman GA, Dean JH, et al. 1980. Examination of bone marrow, immunologic parameters and hose susceptibility following pre- and postnatal exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Int J Immunopharmacol 2 301-310. 

Zhang Z, Chen Q, Li Y, Doss GA, Dean BJ, Ngui JS, Silva EM, Kim S, Wu JY, Dininno F, Hammond ML, Steams RA, Evans DC, Baillie TA, Tang W (2005) In vitro bioactivation of dihydrobenzoxathiin selective estrogen receptor modulators by cytochrome P450 3A4 in human liver microsomes formation of reactive iminium and quinone type metabolites. Chem Res Toxicol 18 675-685... 

CO is removed from the product gas in the gas-dean-up step, where selective CO oxidation takes place at 150°C over a Pt-based catalyst ... 

The reactor types introduced in Sections 1.2 and 1.3 depend on the existence of a catalyst bed, either fixed or moving, for the operation. However, there are multiphase reactions, such as the gas-liquid type, which do not involve the use of a solid catalyst. Gas deaning/purification applications, such as removal of... 

Table 6.18.4 shows the composition of a flue gas produced by a coal-flred power plant before and after modern flue gas treatment. Figure 6.18.9 shows typical steps of flue gas deaning. 

The removal of harmful substances and particulate matter from the syngas is a common exercise in the chemical industry because most catalysts are quickly poisoned by traces of sulfur or nitrogen compounds or deactivated by particulate matter. Hence, the gas deaning required to effectively protect catalysts is usually much more elaborate than complying with current environmental regulations. 

The operation of the clear gas outlet permitted gas extraction up to 22% of the total gas. However, after an accident, it was decided to take the dear gas outlet out of service as the advantages regarding gas deaning do not compensate the disadvantages regarding safe operation [199]. 

It should be noted that FGD systems ate not the only method of controlling flue gas SO2 emissions. Other potoitial methods are fuel cleaning, switching, and blending unit retirement purchase of SO2 emission allowances (in the U.S.) and the use of other technologies such as atmospheric fluidized bed combustion, pressurized fluidized bed combustion, gasifi-catimi with fuel gas dean-up, etc. Only FGD systems ate discussed in this chapter. 

Viscosity can be expressed as a function of reduced density to which the viscosity of the ideal gas must by added. We will use the formulation proposed by Dean and Stiel in 1965 ... 

DATTA-BARUA Natural Gas Measurement and Control DEAN Lange s Handbook of Chemistry, Fourteenth Edition DESHOTELS, ZIMMERMAN Cost-Effective Risk Assessment for Process Design... 

R. R. Deans, A new teclmique for heart cutting in gas cliromatography , Chmmato-gmphial 18-22(1968). 

Figure 10.4 shows a schematic representation of the multidimensional GC-IRMS System developed by Nitz et al. (27). The performance of this system is demonstrated with an application from the field of flavour analysis. A Siemens SiChromat 2-8 double-oven gas chromatograph equipped with two FIDs, a live-T switching device and two capillary columns was coupled on-line with a triple-collector (masses 44,45 and 46) isotope ratio mass spectrometer via a high efficiency combustion furnace. The column eluate could be directed either to FID3 or to the MS by means of a modified Deans switching system . 

Nevertheless, a number of gas chromatographic applications exist, epecially those for the determination of crude oil indicators. Such indicators are used as geochemical parameters for the thermal history of the crude as well as to indicate the possible relationship between crudes from different wells. These indicators comprise a number of isomeric aromatic species, such as the individual alkylnaphthalenes (44, 45), the individual Cio-mono-aromatics or the individual C9-mono-aromatics. The ratio between these isomers gives a definite indication of the crude oil. In general, these systems use a Deans switching unit to make a heart-cut, which then is focused, reinjected and separated on a second column with a different polarity. 

D. R. Deans, An improved teclinique for back-flushing gas cliromatographic columns , J. Chromatogr. 18 477-481 (1965). 

The simplest type of two-dimensional gas diromatography for heart cutting or trace enrichment using a packed precolumn and a capillary column is shown in Figure 8.16 [205]. Almost any modem gas chromatograph could be converted into a similar unit with the addition of a few auxiliary components. Preliminary separation t2dces place on the packed column, the effluent from which is directed either to a vent or to the capillary inlet by the Deans switch, nie effluent reaching the capillary inlet is split three ways. One portion passes to a detector used to monitor the preseparation, a second portion enters the cap Bry column and is... 

Figure 8.16 A simple two-dimensional gas chrtwatograph for packed column fractionation or enrichment using a Deans switch and intermediate trap for transfer to a capillary column. (Reproduced with permission from ref. 205. Copyright Dr. Alfred Huethig Publishers).

---