Nova Analytical Systems: Nova gas analyzer

Thursday, December 18, 2014

#200 - Nova Analyzers from the Field - Episode 9 (Studies of CO2 Absorption / Desorption by Amine Solutions)

We were recently sent a published paper containing a brief mention of a Nova analyzer. The paper itself is about the kinetics of CO2 absorption in various aqueous amine solutions. We have periodically addressed this type of application over the years. As carbon dioxide (CO2) becomes more prominently connected with concerns about greenhouse gases, we expect to see more of it in the future also.

From the Introduction of the paper:

“The separation of acid gas impurities such as carbon dioxide (CO2) and hydrogen sulfide (H2S) from gas mixtures is an important operation in natural gas processing, petroleum refining, coal gasification and ammonia manufacturing industries. Since CO2 is widely regarded as a major greenhouse gas, potentially contributing to global warming, recently, there has also been considerable interest in developing technologies for capturing and sequestering large quantities of CO2 produced from industrial sources such as fossil-fuel electric power generation facilities. Various technologies have been developed for CO2 and H2S removal from gas streams. These include absorption by chemical and physical solvents, cryogenic separation and membrane separation. Among these methods, gas absorption by chemical solvents such as aqueous solutions of alkanolamines is one of the most popular and effective methods.”

Even though this area of study has been active and applied in industry for over 50years, the authors note that complete investigations with mathematical models for absorption and desorption have been lacking. The authors then present a more unified approach in an effort to allow more standardized evaluations of this application across different reactions.

In this study, a novel design of laboratory contactor apparatus was used for interfacial contact between the amine and CO2. This apparatus allows for accurate and easier evaluation of physical mass transfer between the reactants. A diagram of the apparatus as presented in the paper is shown below.

The complete experimental setup from the paper is shown below:

After the dryer and just prior to the fume hood, the CO2 analyzer is shown in the above setup diagram. In this particular study the authors cite the Nova Model 300 infrared analyzer. In our experience, we have supplied a couple of different instruments for this type of application.

- Model 302A – CO2 analysis by infrared detector

- Model 336BT – CO2 analysis by thermal-conductivity (not shown in on-line catalog)

In one application in 2013, we supplied multiple units of Model 336BT in two ranges:

- 0-25.0 % CO2 in Air

- 0-100.0 % CO2 in Air

This application was for a large educational training assembly that involved the same absorption reactions between amine & CO2 mentioned above. The different instrument ranges corresponded to different points in the process before & after CO2 absorption. Purchasing separate instruments allowed simultaneous measurement of each point over a specific period of time.

In most cases, these studies are performed using portable instruments that provide accurate analysis on a temporary / intermittent basis. A wall-mounted version of this instrumentation can also be produced. For study apparatuses that are large enough to be permanently installed, a wall-mount analyzer in its own steel cabinet may be desired.

The study mentioned above is actually described in a two part paper as follows:

Part 1

Kinetics of carbon dioxide absorption and desorption in aqueous

alkanolamine solutions using a novel hemispherical contactor—I:

Experimental apparatus and mathematical modeling.

http://www.sciencedirect.com/science/article/pii/S0009250906003319

Part 2

Kinetics of carbon dioxide absorption and desorption in aqueous alkanolamine solutions using a novel hemispherical contactor—II: Experimental results and parameter estimation

http://www.sciencedirect.com/science/article/pii/S0009250906003381

Authors:

Aqil Jamal

Axel Meisen

C. Jim Lim

Department of Chemical and Biological Engineering,

The University of British Columbia

Vancouver, BC

Canada

V6T 1Z3

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/

Hey, this is Post #200 in our blog. Still haven’t run out of things to say!

Author: Aqil Jamal, Axel Meisen and C. Jim Lim

Publication: Chemical Engineering Science

Publisher: Elsevier

Date: October 2006

Friday, December 12, 2014

#199 - Why Buy 970?

The most popular post on this blog is #70, which is ironically entitled “Post #5 is Our Most Popular Blog Post”. Post #70 was intended to highlight the previous successful post #5 that discussed the growing interest in our 970 Series analyzers for syngas applications.

These posts are probably so popular because there is much world-wide interest in gasification as an energy source. These posts contain specific information and pictures about gas analyzers that can successfully measure O2 / CO / CO2 / CH4 / H2 in produced syngas.

We are often asked questions about the price and configuration of the 970 Series. We do have instruments in our product line that are much smaller and simpler (as pictured below). There are other analyzer manufacturers in the marketplace that also have multi-gas capability like Nova, but who are possibly lower-cost. For a gasification application, is it simply a matter of obtaining an analyzer that will measure the gases of interest?

Not always. Gas analysis is usually only the second half of the whole task. The first half involves extracting the sample, filtering it, and drying it. Doing this properly in a syngas application is important.

There is an old saying about comparing ‘apples to apples’. When we are asked to compare the 970 to another analyzer that resembles the picture above, the first thing that we notice is that all of the sample extraction and conditioning components are missing. Unless the end-user is absolutely confident that the produced gas is clean and dry, this style of instrument will not function properly for very long. Trust us - we have learned that lesson the hard way in the past.

The Nova 970 Series Syngas and Gasification Analyzers are analytical instruments that are industrially hardened but user-friendly.

High temp probe & heated filter at extraction point.
Choice of compression or thermoelectric style moisture removal.
Weather-proof cabinet with climate control.
Stainless steel tubing and industrial components.
Temperature-controlled detectors for O2 / CO / CO2 / CH4 / H2
Accurate H2 measurement in varying background gases.
High measurement ranges available; up to 100%.
Built-in ‘Smart Control’ analyzer functions

Here is some more information plus a link to the 970 section of the catalog.