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Thursday, November 29, 2012

#91 - Part 2 of “Post #5 is our most popular blog post”

I mentioned recently that Post #70, which was called “Post #5 is our most popular blog post (Syngas and Gasification)”, has itself now become our most popular post. I guess if you say something is popular, that proclamation alone is enough to pique some interest.

Another reason for the popularity is probably because of its topic - syngas and gasification. Specifically, the analysis of syngas composition.

In this application, the critical gases are H2 and CO. However, most of our gasification customers want analysis O2 / CO / CO2 / CH4 / H2. We can offer this combination of gases in any range in a single analyzer.





Here’s one that we are building now to support a Fischer-Tropsch process in which H2 & CO are converted into hydrocarbons in the presence of a catalyst.







As a follow-up to Post #5 and Post #70, we have another update to offer on this topic:

Besides having a capable analyzer for this application, it is also important to condition the sample properly before analysis. 
 

Hot Extraction and Filtration

Depending on the feedstock being used in the gasifier, the sample may have a significant amount of particulate in it. It is important to remove the particulate before condensation develops and mixes with the particulate. A heated filter that is mounted behind the probe at the extraction point is a good solution. A version of this filter can even be produced for high pressure samples or for Class 1 Division 2 Hazardous Rated Areas.
 
 
 
Tars
 
Many of our customers have reported to us that if the feedstock is comprised of woodchips or other wood-based matter, there is a strong possibility of tar being in the sample gas. These tars may condense out onto various surfaces. Especially of concern are the optical surfaces of the detectors. We have had some success in removing tars by integrating a gas cooler in a separate cabinet beside the analyzer. This encourages the condensable tars to accumulate on a non-critical surface away from the detectors. Ideally, the cooling assembly should be somewhat modular to allow easy access for cleaning or replacement.
 
Theoretically, a chemical scrubber can also remove the tars. But some of the solvents that might be used, isopropyl alcohol for example, may be carried into the analyzer and provoke a response on the infrared detector. This can be interpreted and presented by the analyzer as a falsely high CH4 reading. So we have been cautious about IR analyses where these types of scrubbers are installed. If the scrubbing solvent is water-soluble, a possibility might be to integrate a water-wash system in front of the analyzer as discussed below. (We haven’t tried this solution yet in this context, but it is an interesting idea.)
 
 
Soluble Gas Removal
 
On some projects where the feedstock is municipal waste with high variability, we have noticed the presence of other gases besides just H2, CO, & hydrocarbons. For example, there may be SO2 or NH3 in the sample gas. These gases may be detrimental to the long-term operation of the analyzer, so it is frequently best to eliminate these gases from the sample. On some gasification projects, we have supplied water-wash systems to scrub out any corrosive gases that are water-soluble.
 
 
 
Multiple Gasifiers or Multiple Sample Points on a Gasifier System
 
Sometimes analysis of multiple points with one analyzer is required. We have supplied an industrially-hardened version of our auto-sequencer for some gasification projects. This system will continually pull a sample from several sample points and send only one at a time to a single analyzer. The auto-sequencer will cycle through the sample points according to a user-defined schedule. Generally, the dwell time on each sample is a few minutes.
 
 
 
 
 
 
 
 
 
 
Not sure if this post will become as popular as the other gasification-related posts. But we will try to continue providing updates on Nova solutions for this interesting application.
 
For information on these and other gas analyzer systems, give Mike or Dave at Nova a call, or send us an e-mail.
1-800-295-3771
sales at nova-gas dot com
websales at nova-gas dot com
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Thursday, November 22, 2012

#90 - Metamerism – Part 1

“Metamerism” is primarily a chemistry term for a type of isomerism in which chemical compounds have the same molecular weight and identical proportions of the same elements, but have different chemical properties because of radicals of different types or in different positions. Sounds complicated, but it’s basically a reference to two chemicals that you would expect to behave the same, but don’t because of minor differences.

In the coatings industry, especially in pigmentary studies, metamerism has a somewhat different meaning, but the idea is still sort of the same. Metamerism is a term used for when two colored samples appear to match under one set of lighting and viewing conditions, but not under another set. Metameric dissimilarity may also be due to differences in observers’ color perception aside from lighting or viewing conditions.

There are instruments available that simulate
various lighting and viewing conditions to
help manage unexpected metameric effects.

I have noticed that metameric effects are often more pronounced in coating systems that do not have high opacity and where the substrate is colored (non-white), or where the system is comprised of multiple layers of varying color contribution. Coatings that incorporate different types of coloring material types also seem prone to metamerism (e.g. organic/inorganic colorants or dyes/universal colorants added post-manufacture).

An example scenario might be a manufactured article whose color is designed and agreed to under the viewing conditions at the manufacturing facility, but doesn’t match expectations when the article is completed and moved to the final location. Metamerism may be the reason. (I say ‘may be’ because a legitimate manufacturing error may also be the cause.) During my time in the coatings industry, I dealt with metamerism often enough to appreciate its potential for disruption.

At Nova, we are thankful that we do not have to worry about such aesthetic complexities in our manufacturing process. Making gas analyzers is complicated enough already. But there are a couple of phenomena in gas analysis that remind me a little of metamerism. I’ll talk about those next time.

The Nova blog appears to be about gas analyzers, and yet this post discussed a completely different subject. Literary metamerism.

For information on these and other gas analyzer systems, give Mike or Dave at Nova a call, or send us an e-mail.
1-800-295-3771
sales at nova-gas dot com
websales at nova-gas dot com
http://www.nova-gas.com/
https://twitter.com/NOVAGAS
http://www.linkedin.com/company/nova-analytical-systems-inc-
http://www.tenovagroup.com/

Pictures:
Copyright © INTEKE INSTRUMENT CO. LIMITED
 
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Monday, November 5, 2012

#86 - New Nova Video on Youtube

Very low budget video made at Nova 'studios' and posted on YouTube.




http://www.youtube.com/watch?v=3uhQH9RcJ6U

It is a 3-min presentation intended to briefly show some of the value proposition inherent in Nova continuous gas analyzers.

NOVA Analytical Systems
1-800-295-3771
sales at nova-gas dot com
websales at nova-gas dot com

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Thursday, November 1, 2012

#85 - Caribbean Applications

A couple of my holiday shots. The pictures shown below are of the Noranda Bauxite Mine in St. Anne, Jamaica.


The last time in Jamaica, I drove by this facility and wondered what it was. I subsequently learned that it is part of a bauxite mine facility. Apparently after tourism, bauxite mining and agriculture are Jamaica’s largest industries. Coincidentally, I recently had a telephone call from the Superintendent of this very facility.
 
Copyright © 2007 – 2009 Noranda Aluminum. All Rights Reserved.
 
They apparently have a few diesel engines operating in individual rooms in the plant. The engine exhaust is obviously vented outside of the building. However, if a leak should develop in the exhaust system, it may result in dangerous accumulations of gases inside the building.
 
For the safety of their staff, they wanted to monitor the following gases:
  • Oxygen Deficiency: 0-25%, alarms will sound if the O2 levels drop to 19.5% or lower
  • Carbon Monoxide: 0-200ppm
  • Nitric Oxide: 0-100ppm
  • Sulfur Dioxide: 0-20ppm
These ranges of analysis cover the safe breathing conditions and permissible exposure limits of these gases.
 
To start, they have 3 engine rooms and they want to have some kind of centralized monitoring system. An auto-sequencer will be a good choice here. It is mounted right beside the monitor. This device is basically a series of solenoid valves and pumps which are controlled to pull different samples from different zones in a timed sequence. This will allow one monitor to be used for all three areas.


Eventually, they hope to tie the monitor / sequencer in with a PLC or a data collection system of some kind. But for now, labeled LED lights on the auto-sequencer will show which area is being sampled. And the monitor will show if any alarms are engaged.
 
We sometimes may forget that some of the Caribbean islands have other sustaining industries besides tourism. These regions no doubt struggle with a delicate balance of having profitable industry while preserving the beautiful environments that attract so many travelers.
 
We are occasionally contacted by Caribbean engineers & professionals for emissions analyzers. For example, in Trinidad and Tobago, we have sold continuous and portable flue gas analyzers into the petrochemical and gas process industries there. Legislative initiatives are apparently also moving these islands toward reductions in automotive exhaust emissions. We have also had requests from Curacao for information on emissions analyzers. Cutting back emissions is a good idea anywhere. But in areas that depend so much on pristine environmental beauty, it would seem to be nothing short of mandatory.
 
Nova Analytical Systems
1-800-295-3771
sales at nova-gas dot com
websales at nova-gas dot com
 
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