Maximizing Power from Biomass

James A. Moore
Research Chemist, Arizona Instrument LLC

Introduction
With the world’s population projected to eclipse 7 billion in 2011, and growing at approximately 1.2% per year, finding useable energy resources has become a global challenge.   Diminishing supply and environmental concerns have been brought to light in recent years, exposing fossil fuels, currently the world’s primary source of energy, as unsustainable and potentially harmful to the environment.  Because of this, clean renewable energy sources are controlling more of the available market, and biomass is one of the leading options on this front.

Biomass is renewable energy derived from living organic material, or material that was recently alive.  Wood pellets, corn husks, refuse, black liquor (a waste product of the paper making industry), and alcohol fuels are common examples of materials that classified as biomass.  These sources are more sustainable than fossil fuels and, like fossil fuels, are typically incinerated for energy production.  Understanding and controlling the moisture and ash content of biomass is important for optimizing its efficiency as a fuel.   Further, incomplete combustion generates black carbon, which is a pollutant and major contributor to global warming.  Traditionally biomass materials have been analyzed for moisture using a conventional oven, and ash using a furnace.  These methods are reliable, but often have long test times, which hinder the manufacturer’s ability to address problems that may arise during processing and decrease the materials ability to act as a suitable energy alternative. 

A new method for moisture and ash analysis has been developed that enables accurate moisture

and ash testing.  An instrument using this method was able to provide real time results, and final water and ash concentrations correlated to standard test methods currently used for multiple materials in different industries.  Test times were significantly reduced which affords manufacturers the opportunity to make changes in process quickly and maximize output. 

Data and Testing

Reference Testing
Reference testing details can be found at http://bit.ly/h5mKQ4.      

Moisture and Ash Testing

Moisture and ash testing was conducted on an instrument using the linked testing option.  This allowed for a moisture test to be conducted, then an ash test to be conducted without any user input or interface.  Testing conditions were established prior to testing and in-situ monitoring was conducted.  Waffle pans were preconditioned prior to testing to remove any film that was used to prevent adherence during stacking.  The sample was evenly distributed on the sample pan for each test.  Moisture and ash testing conditions are as follows:

Testing Conditions	Moisture Test		Ash Test
Idle Temperature		50°C	125°C
Test Temperature		125°C	600°C
Ending Criteria		0.5000%/minute	0.0500%/minute
Sample Size		7g +/- 1g	7g +/- 1g
Pan Tare		Standard	Standard
Sample Tare		5 seconds	5 seconds

Table 1. Testing parameters

The testing conditions in table 1 represent the conditions for this specific analysis.  For different materials these conditions would change to optimize results.  Also, since the ash testing begins immediately following the moisture testing the idle temperature and tare parameters may not be used.  For example, if the idle temperature for the ash testing were set at 110°C the instrument would not cool down prior to testing.  Instead it would begin measuring immediately at 125°C, which is the test temperature for the moisture analysis.   The sample mass used is dependent on the user’s testing criteria.  Either the initial sample mass taken prior to the moisture test is used, or the sample mass at the end of the moisture test is used if the moisture content isn’t desired in determining the ash.  The pan tare is not required since the pan mass is removed at the beginning of the moisture test and does not change. 

Sample Storage and Preparation
Sample storage and preparation details can be found at http://bit.ly/himSUA.

Material	MAX® 5000XL		Reference
Wood Pellet	3 minutes	Test Time	16 hours
	5.9757	% Moisture	5.4472
	0.2283	S.D.	0.0331
Pecan Shell	5 minutes	Test Time	16 hours
	12.5823	% Moisture	12.6090
	0.2893	S.D.	-
Wood Chip	4 minutes	Test Time	16 hours
	5.4632	% Moisture	5.435
	0.2243	S.D.	-
Wood Pellet with Pecan Bagger	4 minutes	Test Time	16 hours
	6.1425	% Moisture	6.247
	0.0922	S.D.	-

Table 2. Moisture results for biomass materials

 

Material	MAX® 5000XL		Reference
Wood Pellet	25 minutes	Test Time	1 hour
	1.3293	% Ash	1.397
	0.1021	S.D.	0.1305
Pecan Shell	35 minutes	Test Time	2 hours
	2.1294	% Ash	2.2734
	0.2437	S.D.	0.0944
Wood Chip	40 minutes	Test Time	2 hours
	0.5575	% Ash	0.5373
	0.0463	S.D.	0.0582
Wood Pellet with Pecan Bagger	30 minutes	Test Time	2 hours
	3.7175	% Ash	4.5263
	0.3465	S.D.	1.283

Table 3.  Ash results for biomass materials

Table 1 shows the mean results for moisture testing of four different biomass materials.  The data shows strong correlation between the oven reference and the MAX® 5000XL and repeatability using the MAX® 5000XL.  There is a large variation in test times between the two methods.  Table 2 displays the ash results for the same materials.  Strong correlation and repeatability was also produced between these testing methods, but there was a large disparity in test times.  Also, it should be noted that the test times reported in table 2 under the heading “reference” is only the time that the material is at the prescribed test temperature.  This does not account for the time it takes for the furnace to reach the test temperature or the time it takes for the crucibles to cool to room temperature.  The test times shown under the heading “MAX® 5000XL” are averaged test times for each material taken from when the test starts to when it ends. 

  

Graph 1. Test graph for moisture analysis of wood pellets

Graph 2.  Test graph for ash analysis of wood pellets. 

The test graphs (both 1 and 2) show real time test progress for moisture and ash analysis using the Computrac® MAX® 5000XL.  Adjustments can be made to the test criteria based on the characteristics of the graph.  For instance, the test graph for ash shows very little change in the ash content of the material after 2400 seconds.  From this the ending criteria can be changed to optimize the test times if it is desired. 

Conclusion

Remaining competitive in a market is a challenge for businesses and must be addressed as the market changes.  As fossil fuel supplies are depleted and in the wake of recent environment tragedies, the world’s energy suppliers will continue to search for safe, renewable and inexpensive sources in order to meet demand.  This has provided an opportunity for nontraditional resources, such as biomass materials, to grab the increasingly available market shares. 

Rapid loss-on-drying and ash content analyzers are essential instruments for companies producing biomass materials.  Their implementation significantly reduces testing times associated with traditional testing methods, which allows companies to bring their products to market faster and increase their production.  Additionally, these instruments save money by reducing energy costs, increasing employee output, and removing testing variables.   These updated testing features will aide biomass material manufactures in maximizing their control of the available market. 
Maximizing Power from Biomass Printable Version

ARIZONA INSTRUMENT LLC
3375 N. Delaware St. | Chandler, AZ 85225
(800) 528-7411  | Fax (602) 281-1745

www.azic.com | sales@azic.com

Manufacturing Food Security

MANUFACTURING FOOD SECURITY

Introduction

All living things require nourishment, and people get most of the energy needed to sustain life from food consumption.  For many, food security is a constant problem, and obtaining food is a daily struggle.  The Food and Agriculture Organization of the United Nations estimates that 868 million people in the world are malnourished, which has been linked to an increased risks in illness, underdevelopment of bone and tissue, and poor mental health.^[1] In recent research Cook et. al. concluded that even people with marginal food security were at an increased risk than previously thought for adverse health and development outcomes.^[2]  This problem is further complicated by the geographic location of the people most effected by starvation compared to the location of the food surpluses that exist worldwide.  Oftentimes a high percentage of the food being delivered to the people in need spoils because of the long spans of time it takes to reach those with shortages.  Long term efforts are being made, moving food sources closer to impoverished people, but short term remediation is also required to get the people food supplies that are both plentiful and storable. 

Food manufacturers are playing a vital role in fighting food insecurity by adapting their current manufacturing practices to incorporate longer shelf life demands while maintaining high quality products that consumers enjoy.   This includes more stringent protocols for making goods, as well as an increase in quality checks for the final products.  One of the key components that requires control is water.  If products have too much moisture then there is an increased risk for molding and spoilage.  If too little water is present then the product may be brittle and have an unsuitable taste.  But how is moisture content reliably determined?

Traditional methods

The Association of Agricultural Chemists (AOAC) has been publishing quality testing methods in food products since 1912.^[3]  Currently these methods for moisture determination use loss-on-drying technology and often require the use convection ovens and/or vacuum ovens, as well as having sample testing  times over one hour.  These methods are accurate, but the lengthy processing times slow the rate of production.  Additionally, these methods don’t allow for dynamic in-test metrics that help provide a complete profile of the sample as it is being examined. 

Rapid Loss-On-Drying

Rapid loss-on-drying instruments operate using the same principle as traditional oven methods, but are able to address the drawbacks associated to them without changing the ease of use.  Users of these instruments place a prescribed amount of material onto a pan that is sitting on a balance.  Once the correct amount of material is on the pan the instrument heats up to a specified temperature and the water is evolved off of the sample.  Multiple criteria can be used to end the test, but frequently tests are ended when the change in mass is determined to be negligible.  These tests provide the user with real time measurements and often tests take a few minutes instead of hours.

Experimental

Comparative testing was conducted for various products using the Computrac® Loss-On-Drying line of instruments, and a vacuum oven with a procedure similar to AOAC method 925_09.  The vacuum oven was set to 70°C and at full vacuum.  The Computrac® testing used individual parameters stored in the instrument under the names from the table.   The samples tested were prepackaged foods that have a 6 year shelf life on the package.  Both testing methods used 4g of sample and were tested.

Conclusion

For testing shelf stable food products, rapid loss-on-drying instrumentation has proven to provide a more desirable method of moisture measurement when compared to traditional loss-on-drying techniques.  It addresses the drawbacks associated with conventional loss-on-drying while maintaining the ease of use application.  The reduction in test times increases manufacturing efficiency while simultaneously reducing energy costs.  Additionally, this instrumentation is able to provide real time moisture measurements to help users optimize moisture measurement methods.  These reductions and savings can be used to deploy food to those in need more quickly, and reach more people that presently have poor food security. 

James Moore, Research Chemist
Arizona Instrument LLC

For more information contact us at (800) 528-7411 | sales@azic.com | www.azic.com

For a printable version visit www.azic.com

Bibliography

1.       “Undernourishment in 2010-12, by region (millions).” http://www.fao.org/hunger/en/. FAO, Jul. 2013

2.       Cook JT, Black M, Chilton M, Cutts D, Ettinger de Cuba S, Heeren TC, Rose-Jacobs R, Sandel M, Casey PH, Coleman S, Weiss I, Frank DA. “Are food insecurity's health impacts underestimated in the U.S. population? Marginal food security also predicts adverse health outcomes in young U.S. children and mothers.” Adv Nutr. 2013 Jan 1;4(1):51-61.

3.       “About AOAC.” http://www.aoac.org/about/aoac.htm. AOAC, Dec. 2010

4.       Pinstrup-Andersen P. “Food Security: Definition and Measurement.” Food Security. Feb 2009; 1(1): 5-7

5.       Godfray HCJ, Beddington JR, Crute IR, Haddard L, Lawrence D, Muir JF, Pretty J, Robinson S, Thomas SM, Toulmin C. “Food Security: The Challenge of Feeding 9 Billion People.” Science. Feb 2010; 327(5967): 812-818.

Moisture and Ash Testing in Food Processing

Moisture content has been established as an important indicator of shelf life for foods.  Moisture can determine the aesthetics of food, giving estimates to product shelf life regardless of sample properties in a wet or dry state. Ash content is also essential to a food’s nutrition and longevity. With Arizona Instrument LLC (AZI) Computrac^® Moisture/Solids/Ash Analyzers, testing moisture and ash content is an easy pain-free process and can speed up production time and improve food quality control.

Moisture content is one of the most important characteristics in consumer sensory perception of food. Change in moisture content will dramatically affect flavor and texture as well as physical and chemical properties, as water gives chemicals a helpful medium to catalyze chemical reactions (water activity). The presence of free moisture is directly related to water activity; the higher the water activity, the more susceptible the food will be to interactions with microbes and its environment. Computrac^® series of moisture analyzers are the fastest, most accurate tools for determining free moisture content.

Determining changes in moisture over time is essential in choosing the best packaging materials to maintain food longevity. The amount and type of packaging, the volume of food stored and the environment all can change the water content over time. Knowing and plotting water content is a useful way of locating the right packaging for each environment which improves shelf life.

The analysis of ash content in foods is simply the burning away of organic content, leaving inorganic minerals. This helps determine the amount and type of minerals in food; important because the amount of minerals can determine physiochemical properties of foods, as well as retard the growth of microorganisms.  Therefore, mineral content is a vital component in a food’s nutrition, quality, and, like water, microbial viability.  Arizona Instrument has instruments that reach 600°C, capable of ashing food samples without destroying the minerals within it, and is an integral part of the food manufacturing process.

Foods have high and low moisture content limits beyond which the product becomes objectionable from either a sensory or safety perspective. In dry brittle foods with low moisture content, such as dry cereal and dehydrated foods, upper moisture content limit is important; the food can absorb water and become moist, undesirable and prone to microbe contamination. In wet foods, such as muffins and sauces, the lower moisture content limit is monitored to make sure the food doesn’t become stale or distasteful. Finding and testing for these limits is essential to produce accurate manufacturer specifications for moisture. Guaranteeing food falls within these limits ensures the production of a quality food product that will not expire prematurely. Each food also has its own longevity and packaging concerns as well as mineral content considerations.

From cookies and mints, to flour and animal treats, we have tested all types of food for our customers. Using Computrac^® analyzers to test for moisture, solids and ash content in place of comparable AOAC standards or vacuum oven test, manufacturers can significantly reduce test times without sacrificing accuracy; which again, speeds up production time and improves food quality control.

Manuel Oropeza, ChemistArizona Instrument LLC
(800) 528-7411 • sales@azic.com
www.azic.com

The Water Factor in Medical Device Resins

Introduction

The Health Care industry has increased its needs for specialized devices over the past decade, which has led to a new frontier of resin and polymer development designed to keep the quality of care high while minimizing cost.  With these goals in mind, the resins being used for medical devices are scrutinized more thoroughly than other resins that require less regulatory compliance.  Analyzing a product for outgassing, deformation, and reactivity, among other things, has become part of the daily routine for manufacturers, molders, and final inspection personnel before an item can be shipped or used.  This additional testing and control also includes the amount of water that is allowed in the resins, since this will greatly influence the final product's rigidness, consistency, and lifetime, as well as the quality of care that will be provided to the customer.  Oftentimes the quality control of the materials is closely monitored using testing equipment defined in an IQ/OQ/PQ: installation qualification (IQ), operational qualification (OQ), and performance qualification (PQ) to ensure that the instruments are effective, and the quality of the product is consistent. 

Moisture Determination

As an alternative to the Coulometric Karl Fisher titration, Relative Humidity (RH) sensor moisture detection was first used as a method for determination of water in materials in 1997, with the introduction of the Computrac® 3000 Moisture Analyzer by Arizona Instrument LLC.  This method uses a thermoset polymer capacitor that has a selective response when in the presence of water, the same way that many RH sensors work in traditional settings such as houses, laboratory controlled environments, and dry boxes. 

Medical device resins are sealed in a sample vial, and then transported into an oven chamber with inert gas blown through it.  As the material gets hot, water molecules evolve off and are carried to the sensor via the carrier gas.  The sensor is exposed to the water molecules and a measurable change in the electronic activity takes place. This method requires no solvents, making it an environmentally friendly alternative to traditional chemical titration.  The instrument provides in-situ moisture measurements, which allows users to monitor performance in real time.  Additionally, it has a lower detection limit of 10ppm, and is more rugged than Karl Fisher titrators, making it a suitable instrument for moisture analysis in manufacturing facilities, as well as Quality Control and inspection labs.  This technology is now being adopted as the standard test method and is described by ASTM D7191, Standard Test Method for Determination of Moisture in Plastics by Relative Humidity Sensor.  This instrument also meets the high demands of performance given in an IQ/OQ/PQ.  

With major advances in technology, the medical device community is also taking advantage of new RAPID loss-on-drying methods for moisture determination.  These instruments use the same principle as traditional loss-on-drying techniques, but address the shortcomings of the method.  Sample material is heated on a balance and real time measurements are providing immediate feedback and moisture concentration.  The Computrac® MAX® 4000XL instrument, manufactured by Arizona Instrument LLC, provides a parameter development expert program that allows users to optimize testing conditions, such as sample size, test ending criteria, testing temperature, idle temperature, temperature rate, etc.  The chassis of this instrument is made of steel, which prevents cracking in the case and cool air from entering the testing chamber, which would influence the results.  These new techniques are being adopted as standard testing methods and are described by ASTM D6980-12, Standard Test Method for Determination of Moisture in Plastics by Loss in Weight.  Like the Vapor Pro® 3100L, the MAX® 4000XL meets the performance standards set forth in typical IQ/OQ/PQ testing. 

Testing

Sample Prep – A medical grade TPU was selected for analysis.  The material was stored wet in a 1 gallon plastic Ziploc bag prior to testing.  An initial analysis was conducted to determine the water content prior to drying.  The material was then dried in the Dri-Air HP4-X 25 plastics drying hopper for 6 hours prior to testing.  The material remained in the dryer during testing due to the hygroscopic properties of the material. 

Test Conditions - Reference testing was conducted using the Mitsubishi CA-100 Coulometric Karl Fischer titrator.  The parameters were: sample size – 0.5g +/- 0.1g, temperature – 90°C, purge/preheat/cooling – 1/2/2, ending sensitivity – 0.1µg/sec.

Corollary testing was conducted using the Computrac® Vapor Pro® 3100L.  The parameters were: sample size – 2g +/- 0.2g, temperature – 105°C, purge – 50 sec., ending criteria – rate < 0.1µg/sec. 

Results 

Graph 1.  Total moisture curve of pre-dried TPU  

From the table, the results using the two different instruments with similar testing conditions correlate to each other.  The Vapor Pro® did show an improvement in the relative standard deviation, but did require a slightly longer test time than the Karl Fischer.  Additionally, the Vapor Pro® provided real time data points that could be used to graph the total moisture curve.  This allows for better monitoring of the product, or diagnosing possible problems with the instrument.  This feature was not available for Karl Fischer titrator. 

Conclusion

The development of an alternative to Karl Fischer moisture analyzer has been achieved, and can be used for moisture specific analysis of medical device grade resins.  The Computrac® Vapor Pro® 3100L moisture analyzer successfully uses Relative Humidity sensor technology for selective and accurate moisture measurement.  The instrument reduces the use of hazardous organic solvents makes it an environmentally friendly alternative, when compared to current Karl Fischer technology.   The results between the two methods of detection of H₂O content in TPU strongly correlate, with the Vapor Pro® 3100L providing real-time data that can be used to provide a complete profile of the TPU. 

James Moore, Chemist

Arizona Instrument LLC • 3375 N. Delaware St., Chandler, AZ 85225 • www.azic.com
(800) 528-7411 • sales@azic.com