Sulfur analyzer

Method of Operation. The catalyst was activated in the reactor by first calcining at 232.2 C (450 F) and then sulfiding with a mixture of 5.14 volume percent H2S in H2. The reactor was then brought to the operating conditions and the flow of hydrogen and oil started. After about 32 hours of operation for catalyst stabilization, representative product oil samples were taken at specified reactor conditions. The product oil samples were analyzed for sulfur and nitrogen contents with the help of a Leco Model 634-700 automatic sulfur analyzer and Perkin Elmer Model 240 elemental analyzer, respectively. 

The cleaned coal was dried at 110 C overnight and then sampled for analysis. Moisture, ash, and pyritic and sulfate sulfur were determined by ASTM procedures (11). Total sulfur was determined by high-temperature combustion using a Fisher Total Sulfur Analyzer. Organic sulfur was determined by difference. 

The total sulfur concentration of the coal charged to the reactor and that of the solid product were determined by use of a Fischer Total Sulfur Analyzer. Liquids were analyzed on a Perkin Elmer Sigma 3 gas chromatograph and gas analyses were performed on a Varian Model 3400 gas chromatograph. 

Several commercial sulfur analyzers are based on the fact that, in high-temperature combustion in oxygen, sulfur is predominantly converted to sulfur dioxide, which can readily be measured by infrared spectroscopy (LEGO Corp., St. Josephs, Michigan), thermal conductivity (Kirsten, 1983), or titration (Mansfield and Gibboney, 1977). The drawback to this approach is that the conversion to SO2 is not complete and the extent of conversion is dependent on sample matrix. In addition, these analyzers generally require 10-100 mg or more of sample. 

The primary components of automobiles are steel or aluminum, so one of the fastest methods for analysis with the least amount of preparation of the sample is the emissions spectrometer. From Table 2.1, we can see that a carbon sulfur analyzer, such as a Leco, or atomic absorption spectrophotometer scanning electron microscopy (SEM) x-ray and GC-MS are also used for this type of analysis. However, an emissions spectrophotometer is most often used because of its lack of sample preparation. Again, it is not our attempt here to go into great detail on each method. Within an automotive analytical laboratory, however, speed is a priority so that a material is identified and classified rapidly. An emissions spectrophotometer is such an instrument. 

There are also other vendors who are working on other technologies to market new on-line sulfur analyzers for an expected rise in demand for instrumentation in the refineries and blend terminals. 

FIG. 2—The calibration curve for a bench top sulfur analyzer the open circles are the calibration data points and the solid line is the linear fit with weighted error bars. 

Data were also collected from a different bench top sulfur analyzer at a refinery laboratory over a period of one month. Again, all the measurements were carried out with one calibration curve. For the repeatability evaluation, two diesel products and a gasoline product were used. The gasoline and one of the diesel samples contain 50 ppm sulfur. The other diesel sample has 10 ppm sulfur. For each sample, two successive readings were obtained within 10 min. from two different specimens by the sample operator. A total of 26, 36, and 32 pairs of results were obtained over a month for the 50-ppm diesel, 10-ppm diesel and the gasoline samples respectively. The difference between each pair was calculated and the results are shown as histograms for the three samples (see Fig. 5). The repeat measurement standard deviation and the site repeatability were foimd and the results are listed in Table 4. 

Design Challenges for a High Speed Sulfur Analyzer for Hydrocarbons... 

Significant advances in sample introduction, combustion technique, and the handling of combustion byproducts have been incorporated into the basic on-line Sulfur by UV Fluorescence analyzer. The implementation of these new techniques has yielded a continuous rapid sulfur measurement capability that is based upon the reliable and well-established D 5453 standard test method. Figure 4 describes a typical high speed sulfur analyzer. 

To demonstrate the linear response of the High Speed Sulfur Analyzer, a 750.1 mg/kg reference diesel sample was diluted eight times sequentially on a 1 1 basis with a near-zero sulfur light hydrocarbon of similar density. Each of the nine samples was injected multiple times in a HSS series analyzer that was set for a 1000 ppmw full scale range and calibrated with the neat reference material. The data are summarized in Table 4, and the correlation is plotted in Fig. 10. The r2 correlation coefficient was 0.999. The data in Table 4 indicate a % RSD of better than 10.1 % in the 4-28 mg/kg sulfur range. At the higher sulfur levels, between 50-750 mg/kg, the %RSD is between 4-0.6%. Figure 10 illustrates the correlated linearity data. 

High Speed Sulfur Analyzer 24-hour Repeatability Sample Gazole/Gasoil 131.4 mg/Kg... 

Finally, Table 5 compares the results obtained on six ASTM Ultra-Low Sulfur in Diesel (ULSD) cross check samples. Data from a D 5453 laboratory analysis and data using a process analyzer 6200 and 6200 HSS are compared with ASTM D 5453 consensus values based on about 100 measurements from the participating industry laboratories. Both the standard Model 6200 process analyzer and the 6200 High Speed Sulfur analyzer results are in excellent agreement with the ASTM consensus values as well as the D 5453 results obtained in ow laboratory. 

Pyro-Electrochemical On-Line Ultra Low Sulfur Analyzer... 

Pneumatic nebulizer, 17, 51 Polarization, 128 Polarized energy dispersive x-ray spectrometry, 128 Pooled limit of quantification, 116 Pyro-electrochemical on-line ultra low sulfur analyzer, 152... 

Like cements, the elemental composition is determined by XRF or AAS techniques. The XRF bead is made using lithium tetraborate at 1050°C. Sulfide content cannot be determined by XRF. Sulfite, SO3 , and sulfate, S04 , are safely analyzed by XRF. Na2C03 -I- K2CO3 fusion is carried out for Ca, Mg, Fe, and A1 analysis by AAS. Lanthanum chloride is used as a sulfate interference suppressant. Gravimetric sulfate determinations are also carried out by precipitation as barium sulfate. The Leco Carbon-Sulfur Analyzer can also be used for quality control purposes. The fluoride is determined by XRF or a pyrohydrolysis method. The measurement of particle size distribution is carried out in a manner similar to that for cements and clays. 

X-ray microprobe, neutron activation, and electro-analytical methods have been mentioned in the literature. For irons and steels the carbon and sulfur level is determined by a Leco carbon/sulfur analyzer or similar in addition to the elemental analysis. Similarly, the hydrogen content is measured in aluminum by a hydrogen analyzer. Table 4 summarizes the elements determined for various metals and alloys. 

Accurate determination of elemental sulfur in petroleum and its distillates (petroleum products) is of significant industrial importance. It is being determined routinely by several techniques, for example, by the differential pulse polarography technique. The detection limit is 0.1 pg per g, but chemical treatment of the sample is needed. The wet chemical method of activated Raney nickel has been successfully employed with a detection limit of 0.1 pg per g. Also in this case preconcentration of sulfur is needed. By using the Houston Atlas sulfur analyzer in which... 

Figure 8.61 (a) Schematic of the X-ray transmission NEX XT system showing the flow cell, source, and detector. (b) The Rigaku NEX XT on-line sulfur analyzer. (Courtesy of Applied Rigaku Technologies. Inc., TX. www.rigakuedxrf.com.)... 

SO2 removal capacity of the sol-gel derived sorbents was also studied in a fixed-bed adsorber system, which includes an adsorber column packed with sorbent pellets, a feed flow control system, and a sulfur analyzer (HORIBA, PIR-2000). A computer data acquisition system was incorporated into this adsorber system in order to obtain continuous breakthrough curves of SO2. The fixed-bed was made from dense y-A Os tube of 6 mm ID and 8 mm OD. The central portion of the bed was packed with the sorbent, with both ends of the bed filled with quartz particles (0.5 mm in diameter). The feed was air containing 2000 ppm SO2, and the fixed-bed temperature was 400°C. 

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