CO2 Mechanics Blog

Practical knowledge, tools, tips and techniques for developing and implementing innovative CO2-enabled clean manufacturing processes, products, and production lines.

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  • SUBJECTS

    • Forward

    • Scope and Objectives

    • The CO2 Backstory

    • History of CO2 Composite Spray

    • CO2 Processing Technology

    • CO2 Processing Units

    • Contamination Control

    • Manufacturing Waste Minimization

    • Environmental Health Worker Safety

    • CO2 Application Profiles

    • Clean Solution Innovation Process

    • CO2 Guy Presentations

  • CO2 DATA

    • CO2 Properties

    • CO2 Diagrams

    • CO2 Safety and Health Data

    • CO2 in the News

  • GLOSSARY

    • Technical Terms

    • Blog Icons

    • How to use this Blog

    • Copyright Notice

  • VIDEOS

    • Corporate Videos

    • Process Videos

    • Product Videos

  • AUTHOR

    • Author Bio

    • Dedications

    • Published Papers

CO2 Backstory 1.3.6

Future CO2 Developments

CO2 Processing Units (CPU®)

CO2 technology innovation continues today with an emphasis on new market and application development, and more particularly the development and implementation of a new business model innovation uniquely adapted to this disruptive technology. For example, CO2 surface treatment technology performs three basic functions (or processes) – precision cleaning, cooling, and modification. CO2 technology performs these functions in unique ways which are lean, green, 100% dry, inherently compatible with materials and tools, and enhance performance of manufacturing processes requiring one or a combination of these functions [36]. 

CO2 Backstory 1.3.5

CO2 Process Fluids

Purification, Delivery, and Recycling

During the initial CO2 technology development period, adjunct innovations were co-developed to support the CO2 immersion and spray cleaning platforms. Shown in Figure 1-20, technologies include single- and multi-stage CO2 distillation systems, cold-trap refluxing stills, in-situ condenser-purifiers, and high pressure-capacity CO2 delivery systems.

CO2 Backstory 1.3.4

Automated Spray Cleaning

SnoBot and CleanFlex

Small affordable (so-called) desktop robots were being introduced in the early 1990’s. While watching the movie Jurassic Park in a theater in 1993, I saw a small robot – called the Mitsubishi RV-M1 – being used to pick up, rotate, and place eggs in a dinosaur nursery incubator.   Fascinated by the small robot operation, I quickly realized that this type of system would be the perfect automation solution for the new CO2 spray cleaning technology that I was just beginning to develop at the time. Shown in Figure 1-16, the first prototype SnoBot™ robotic CO2 spray cleaning system was developed by late 1995 using the RV-M1 robot. The SnoBot system featured an end-of-arm CO2 composite spray applicator equipped with a red light laser pointer to assist with teaching point-to-point CO2 spray cleaning paths using the built-in teach pendant and BASIC (Basic All-Purpose Symbolic Instruction Code) programming platform.

CO2 Backstory 1.3.3

CO2 Composite Spray

Pencil Snow Blaster

Concurrent with centrifugal liquid CO2 immersion cleaning process commercialization, development of a new CO2 spray cleaning technology also began in the early 1990’s. CO2 spray cleaning is a selective line-of-sight surface cleaning process. The first precision CO2 spray cleaning system, called the SNOGUN™, was developed by Dr. Stuart Hoenig, Arizona State University in the mid-1980’s [27]. The SNOGUN innovation was refined by Hughes Aircraft (and many others) in the 1990’s. My interest in the SNOGUN was that a CO2 spray cleaning process complements a CO2 immersion cleaning process. Analogous to conventional solvent vapor degreasers, a CO2 spray (wand) provides a final clean or rinse step to remove thin films and micro-particulate contamination following general cleaning using centrifugal liquid CO2 immersion processes. 

CO2 Backstory 1.3.2

Centrifugal Liquid CO2 Immersion

SuperFuge

Design and development of a new high performance dense fluid immersion cleaning system began in late 1989. Previous studies at Hughes comparing the cleaning rates and efficacy between scCO2 and liquid CO2 showed that – although not as effective as scCO2 for certain polar or more complex (waxy) contaminants – liquid CO2 demonstrated higher contaminant carrying capacity and faster cleaning rates, particularly for non-polar oily hydrocarbon and silicone contaminants. Lack of solubility for a particular contamination was easily remedied with the addition of a suitable liquid CO2 fluid modifier (2% to 5% by vol.) comprising various mixtures of non-ionic surfactants (i.e., Dow Triton® X-15) dissolved in a carrier solvent such as a paraffin, ester, or alcohol.

CO2 Backstory 1.3.1

Early Supercritical and Liquid CO2 Processes

Mr. Orval Buck

The first CO2-based immersion cleaning system was constructed and tested by Mr. Orval Buck at Hughes Aircraft Company in 1984, essentially adapted from a German supercritical CO2 (scCO2) extraction process for decaffeinating green coffee beans [10]. Shown in Figure 1-4, the first scCO2 cleaning system comprised an insulated high pressure vessel (retrofitted isostatic press) which was temperature-regulated using flexible silicone-insulated heating tape and a thermostatic controller. A contaminated production part was loaded into the vessel through a topside threaded closure. Following purging with CO2 gas to remove internal atmosphere (i.e., residual air and moisture), the vessel was fluidized using a high pressure pneumatic pump supplied by a cylinder of high pressure liquid CO2. The vessel was compressed to various supercritical fluid conditions ranging between 2,000 and 5,000 psi with the pressure vessel heated to a temperature of between 40 and 60 degrees C.

CO2 Backstory 1.3

CO2 Technology Development

Faster, Better and Cheaper

CO2 technology described in this blog-eBook represents more than 30 years of process, application, and commercial product development beginning in 1984 and continuing to the present day. The old adage – Necessity is the Mother of Invention – has been and continues to be a major driving force behind the CO2 technology innovation process. Discrete cleaning, surface modification, cooling, purification, and recycling technologies represent derivatives – various CO2-enabled solutions ideated, developed, and advanced to jointly solve production cleaning and contamination control problems encountered in numerous end-user manufacturing applications to achieve specific performance requirements. In this regard, rapid changes in manufacturing technology, shrinking product features, and increasing global competitiveness have driven the need for sustainable manufacturing technology - faster processing, better performance, and a lower cost of production.

CO2 Backstory 1.2

CO2 is Part of the Solution

Recycled CO2

The human part of the Earth’s carbon cycle comprises our societal and industrial activity - our so-called carbon footprint.   This issue has fostered a contentious and controversial global debate regarding the connection between increasing human-based CO2 emissions and alleged global warming. It is noteworthy that based on analysis of polar ice and sediment core samples dating back millions of years, the Earth was much warmer and richer in atmospheric CO2 (and plant life). In a relatively recent geological past, absent most modern humans and all industrial activity, atmospheric levels of CO2 were nearly 18x higher than today, 7,000 ppm compared to 400 ppm, and vast green forests and jungles flourished across the planet. In fact, the current atmospheric levels of CO2 are much less than optimal for healthy plant growth [6].

CO2 Backstory 1.1

Carbon Dioxide (CO2) is Universal

Abundant and Natural

Carbon dioxide (CO2) is an abundant, natural, and renewable manufacturing resource. To begin with, you are a CO2 production plant. Shown in Figure 1-1, with each breathe of air, comprising about 78% Nitrogen (N2) and 21% Oxygen (O2), you expire a small amount of CO2 gas along with unused N2 gas, water vapor (H2O), and organic (carbon-based) vapors as metabolic by-products. Over the course of a day, you produce about 2.3 lbs. of gaseous CO2 [1].   This equates to filling a little over two 16 ounce water bottles with liquid carbon dioxide each and every day. Over a year, you fill nearly two 55 gallon drums. Over your lifetime, you will fill more than fifteen average-sized hot tubs – about 8,000 gallons of liquid CO2!

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