Sulfur and Mercury Sampling in Refineries Using SilcoNert™2000
SilcoNert™2000 is inert to sulfur and mercury compounds to part per billion (PPB) levels.
Refinery and natural gas samples often contain trace amounts of sulfur containing compounds like hydrogen sulfide (H2S) and mercury containing compounds. Sulfur, hydrogen sulfide and mercury compounds can interfere with reactions, poison catalysts in petrochemical processes, and damage equipment. Because sulfur and mercury compounds quickly react with stainless steel surfaces, accurate determination of these compounds is impossible when samples are collected and stored in untreated sample cylinders. (see figure 1)
- Reliable sulfur and mercury sampling to ppb levels
- Accurate sampling the first time, every time
- Reduce lab costs
- Accurately grade feedstock
- Detect costly process upsets
- Improve product yield 112
SilcoTek’s innovative coating, SilcoNert™2000, bonds an inert silicon layer into the surface of stainless steel, preventing active compounds, like sulfur or mercury, from reacting with or adsorbing to the steel. The high temperature, durable coating will conform to most intricate surfaces while maintaining high dimensional tolerances. SilcoNert™2000 will deform with tubing surfaces allowing for radius bends and will not interfere with threaded or compression joints; making SilcoNert™2000 the ideal coating for refinery gas sampling, flare gas sampling, and process sampling.
SilcoNert™2000 treated gas sampling equipment is ideal for collecting and storing samples containing ppb levels of sulfur compounds, such as those found in natural gas or beverage-grade carbon dioxide. SilcoNert™2000 treatment ensures that sulfur compounds, like hydrogen sulfide (H2S) or other highly active compounds remain stable during transport from the field to the laboratory, resulting in accurate, reliable sampling the first time, every time.
Figures 2 through 6 show significant stability of the SilcoNert™2000 surface when exposed to common sulfur containing compounds like hydrogen sulfide (H2S), mercaptans, and other sulfur containing species. Typical sulfur compound recovery rates exceeded 90%, even when sampling low ppb concentrations.
Stable Mercury Results
SilcoNert™2000 is utilized in a wide variety of mercury sample containment and transport applications such as stack and flare gas sampling, CMMS sampling, down-hole sampling, and natural gas pipeline sampling.
To measure the impact of SilcoNert™2000 treatment on adsorption of mercury during storage, we compared the performances of 304 grade stainless steel gas sampling cylinders (Swagelok®, Solon OH) with and without SilcoNert™2000 treatment. We filled each cylinder with 8μg/m3 of elemental mercury (approximately 1 part per billion) (Spectra Gases, Alpha NJ) and assessed the mercury concentration in each cylinder over time to determine changes in mercury concentration.
Detection was achieved by direct interface gas sampling to an atomic absorption detector. The sample pathway regulator and tubing were SilcoNert™2000 treated to ensure accurate transfer. The data in Figure 7 demonstrates that SilcoNert™2000 treatment provides a stable surface for elemental mercury, untreated stainless steel does not. Based on these results, SilcoNert™2000 treated steel or stainless steel components and tubing in CMMS and sorbent tube mercury sampling systems will dramatically improve analytical reliability in refining applications.
Value of an Inert Pathway
SilcoNert™2000 treated sampling and transfer equipment results in more accurate sampling and faster cycle times. SilcoNert™ 2000 treated sample pathways improve accuracy and reliability of data for sulfur, mercury, H2S and methyl mercaptan sampling. Downstream processes can be more precisely controlled, resulting in a significant cost savings. Shorter sampling cycles translate directly into more samples collected and analyzed in a given period of time. Process upsets can be detected faster while false readings can be eliminated. Typical savings can be calculated by looking at average per-hour cost of operating a process that relies on accurate quantification of sulfur compounds. A 1 hour delay in operations can cost an 800,000 tpy ethylene plant $50,000. A 250,000 tpy LDPE unit will cost operations $36,000 for a 1 hour upset while an EBSM styrene plant will cost $33,000 (See Figure 8).
