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CO2 Cleaning and pH Control in the Food Industry
C H A P T E R
10 CO2 Cleaning and pH Control in the Food Industry Jan Vansant*, Christian Rogiers† †
*Cold Jet LLC and VFB bvba, Leuven, Belgium Cold Jet LLC, Sr. VP Marketing, Loveland, OH, United States
10.1 INTRODUCTION CO2 blasting, also known as dry ice blasting or dry ice cleaning, is a revolutionary blasting method that uses CO2 in its solid form as a cleaning media. CO2 gas is naturally found in our environment and is commonly manufactured in four forms: blocks, slabs, nuggets, and pellets. It is moderately reactive and nonflammable. At 78.51°C or 109.3°F, carbon dioxide changes directly from its solid phase to its gaseous phase through sublimation, or from gas to a solid through deposition. The different forms of dry ice can be seen below in Fig. 10.1. Carbon dioxide plants do not actually manufacture carbon dioxide–they purify a waste stream from another process, then liquefy the gaseous product through pressurization and temperature reduction. About 90% of all CO2 used to produce dry ice is recycled as a byproduct from ammonia, natural gas, or ethanol manufacturing processes. Alternatively, carbon monoxide is manufactured and then converted into CO2 through a shift catalyst or a proprietary solution. Approximately 90% of dry ice is used as a cooling agent in a cold-chain management
Gases in Agro-food Processes https://doi.org/10.1016/B978-0-12-812465-9.00024-4
system for the food and pharmaceutical industries while the remaining 10% is used as blasting media for cleaning. The result is a dry, nonabrasive, nontoxic cleaning method with no secondary waste. Dry ice blasting is an efficient and cost-effective way for industries to maximize production capability, quality, asset utilization rates, and asset life. In some ways, Cold Jet dry ice blasting is similar to sand blasting, plastic bead blasting, or soda blasting. The media is accelerated in a pressurized air stream to impact a surface to be cleaned or prepared. CO2 blasting works because of three contributing factors: the kinetic effect, the thermal shock effect, and the thermal-kinetic effect. Kinetic Effect: The kinetic effect in the dry ice blasting process is responsible for most of the cleaning effect at ambient and normal processing temperatures. When the dry ice particles are dispensed into the compressed air stream, they are accelerated and hit the targeted surface at high speeds (approximately 340.29m/s). These high velocities cause the contaminant to crack and loosen. The kinetic effect is responsible for most of the cleaning effect, and therefore particle speed and size are important parameters of dry ice
571
# 2019 Elsevier Inc. All rights reserved.
572
FIG. 10.1
10. CO2 CLEANING AND PH CONTROL IN THE FOOD INDUSTRY
Dry ice forms.
blasting (K.E. ¼ ½ m v2). Particle speed is mainly dependent on blasting pressure and aerodynamics. It is highly influenced by factors such as nozzle type, particle size, shape, machine dimensions, and hose dimensions. Thermal Shock Effect: The low temperature of the dry ice (78.51°C/109.3°F) causes the contaminant to shrink and become brittle, aiding in its removal. The temperature gradient created between the contaminant and the substrate creates rapid microcracking of the contaminant, causing the bond between the contaminant
FIG. 10.2
material and the substrate to fail. This allows the dry ice to permeate the contaminant more effectively. The cooling is a surface effect only, and does not rapidly cool the equipment being cleaned. Thermal-Kinetic Effect: The impact energy dissipation and rapid heat transfer between the dry ice and the surface cause instantaneous sublimation of the solid CO2 into gas. As demonstrated in Fig. 10.2, CO2 expands to nearly 800 times the volume of its solid media form and lifts the contaminant from the substrate.
Dry ice sublimation.
10. PARTICULAR CO2 APPLICATIONS; CLEANING, pH CONTROL
10.2 KEY BENEFITS
10.2 KEY BENEFITS Maintaining superior hygiene standards is essential in the food industry. Cold Jet dry ice cleaning produces a superior clean that improves the quality of finished goods, increases asset utilization rates, and extends equipment life. The process utilizes the same food-grade CO2 used in carbonated beverages. Because the dry ice media sublimates upon contact, dry ice blasting is a dry process that leaves no secondary residue. Dry ice cleaning is environmentally sustainable. It utilizes CO2 that has been reclaimed from refining industries and does not contribute to the greenhouse effect. While there is no way to completely keep CO2 from entering the atmosphere (dry ice constantly sublimates at a rate of 3%–5% when it is not in use), the creation of dry ice gives the CO2 a “second life” before it is returned to the atmosphere. In dry ice cleaning, CO2 is not created—existing CO2 with its beneficial physical phase-change properties is used for cleaning. Dry ice is colorless, tasteless, odorless, and nontoxic. Utilizing Cold Jet dry ice cleaning eliminates the use of environmentally harmful cleaning chemicals and increases operator safety
FIG. 10.3
573
as it eliminates exposure to hazardous cleaning agents. Dry ice blasting supports zero landfill initiatives and helps reduce water and sanitation costs because there is no secondary waste or water left behind to clean up. As shown in Fig. 10.3, traditional methods often utilize chemicals or abrasive media. However, CO2 blasting will not cause damage to the surface being cleaned. The dry ice particles are relatively soft. Dry ice pellets were found to be 1.5–2.0 Mohs, which is soft compared to other blasting media forms. CO2 cleaning will not etch, profile, or change the dimension of a surface harder than dry ice. The low temperature of dry ice causes the contaminant layer to shrink and become brittle, which aids in removal. The temperature change, or Delta-T, created between the surface contaminant and the substrate creates rapid microcracking of the contaminant, which causes the bond between the contaminant and the underlying surface to fail. Dry ice cleaning can usually be performed while equipment is online and still at operating temperatures. Cold Jet dry ice blasting can clean equipment such as proofers, ovens, bread coolers, and bread slicers with little to no disassembly.
Cleaning method comparison.
10. PARTICULAR CO2 APPLICATIONS; CLEANING, pH CONTROL
574
FIG. 10.4
10. CO2 CLEANING AND PH CONTROL IN THE FOOD INDUSTRY
Cleaning conveyor systems with dry ice.
10.3 GENERAL FOOD INDUSTRY APPLICATIONS Conveyor systems are constantly coated in oils, waxes, seasonings, crumbs, adhesives, and sticky labels. Using water to clean conveyor systems can be a time-consuming process because electrical components need to be wrapped and water waste needs to be collected before production can resume. Removing excess water is difficult, and any excess can lead to bacterial growth and product contamination. Cold Jet dry ice cleaning is a dry process, making it the perfect solution for cleaning conveyors in the food and beverage industry because downtime for cleaning is minimized. An example of cleaning conveyor systems with dry ice can be seen below in Fig. 10.4. Labelers get dirty with dried glue, dirt, and grease. The overspray and overflow of glue can cause labeling equipment to function inefficiently. Traditional manual cleaning involves cleaning with chemicals or hand scraping, which can cause damage to tooling. These methods are slow, labor intensive and often
ineffective, leading to expensive part replacement instead of cleaning. Cold Jet dry ice blasting removes dried glue and grease quickly and easily without disassembly, providing a faster clean that reduces labor costs and increases production uptime. Dry ice cleaning does not risk damage to critical surfaces such as cutter drums, gripper drums, glue nozzles/assemblies, or conveyance equipment.
10.4 BAKING Baking facilities need to maintain clean conditions while remembering that food will come into contact with the cleaning agents. The method of cleaning can impact the taste, cooking, rising ability, and overall quality of the finished product. Because the cleaning method can severely alter the product, governments have imposed regulations on if/where chemicals can be used. Due to sanitation issues—mainly the potential for bacterial growth—and potential damage to equipment, water is not always an ideal cleaning medium.
10. PARTICULAR CO2 APPLICATIONS; CLEANING, pH CONTROL
575
10.5 SNACK FOODS
Proofers are used to control humidity to foster the fermentation of dough by yeast, which allows the dough to rise to the correct shape and size. They are often coated in dough, bread, and other baking ingredients. Manual cleaning methods are tedious and require the dough proofer to be disassembled for cleaning. Pressure washing is discouraged because the leftover water waste provides a breeding ground for bacterial growth. By utilizing dry ice cleaning, bakeries can eliminate the need for disassembly before cleaning. Proofers can be cleaned in place, without the associated waste from water blasting. Dry ice is a food grade media. At 78.51°C/109.3°F, the threat of bacterial growth is reduced. During production, waffle cone and wafer oven plates are often coated with carbon build-up, grease, and other contaminants. Manual scrubbing with wire brushes and chemicals can be time consuming, labor intensive, and costly. Cold Jet dry ice blasting can reduce downtime due to cleaning because ovens can be cleaned while they are still hot, without disassembly. Bread coolers are often caked with layers of oil, bread crumbs, and other residue. Pressure washing can strip important mineral oils from the conveyor and requires electrical components to be wrapped. Additionally, all secondary water waste needs to be collected and removed before parts can be reassembled and production can resume. CO2 blasting provides a solution that allows baking equipment to be cleaned in place, without disassembly or wrapping of electrical parts. Because the dry ice media sublimates on contact, the need to remove water residue is eliminated. The blades on bread slicers become covered with buildup from general baking ingredients. This buildup affects the sharpness of the blades, preventing the slicers from creating a clean, sharp cut. Traditional cleaning solutions such as water or steam blasting and hand wiping require disassembly. These methods are also
tedious, risk damage to blades, and are potentially harmful to workers. Cold Jet dry ice blasting allows slicers to be cleaned without disassembly, drastically reducing labor hours. It also provides a nonabrasive cleaning solution that reduces wear and tear on the blades. Bread baggers feed the bread directly from a conveyor or slicer into the bag. When using traditional methods, it takes 96 hours to clean a bagging area. With dry ice blasting, this time is reduced to 5 minutes. On average, a baking facility can pay for a dry ice blasting system in less than one year by cleaning bread baggers with dry ice.
10.5 SNACK FOODS Cold Jet dry ice cleaning enables snack food plants to more easily meet rising sanitation standards while reducing their cleaning time by 30%–80%, effectively reducing labor costs, waste materials, and downtime. Snack food facilities lower their productivity costs because equipment and tooling are cleaned in place without disassembly, minimizing downtime and avoiding unnecessary startups and reassembly. By providing a faster, nonabrasive clean, dry ice blasting reduces the time it takes to get machinery back into production. CO2 blasting saves snack food plants an average of $17,979 per month in labor costs. Additional savings occur when cleaning beneath conveyors, between conveyors, and conduits and also when cleaning packaging equipment. Ishida weighers receive finished snack foods such as potato chips, pretzels, and cheese puffs from a conveyor and measure and weigh the material for bagging. The primary components of the weigher include radial feeders and the base or weigh head. Weighers are constantly coated with oil, grease, seasoning, and crumbs, and they need to be cleaned regularly in order to continue to accurately weigh and measure materials.
10. PARTICULAR CO2 APPLICATIONS; CLEANING, pH CONTROL
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10. CO2 CLEANING AND PH CONTROL IN THE FOOD INDUSTRY
FIG. 10.5
Dry ice blasting an Ishida weigher.
Hand scraping, wire brushing, and chemical soaking/wiping have been used to remove the hardened grease and oil. However, these methods are slow, labor intensive, and require disassembly. Cold Jet dry ice blasting can remove the contaminants quickly, resulting in lower labor costs and higher production time. With dry ice, packaging equipment is cleaned with minimal disassembly and without damage. An example can been seen above in Fig. 10.5.
10.6 BOTTLING SOLUTIONS Cleaning with dry ice allows bottling plants to clean in difficult places and maintain hygiene standards while reducing cleaning costs. Bottling plants can often reduce cleaning labor and material costs by 70% by implementing CO2 blasting. Additionally, they will also save by reducing cleaning materials, secondary water waste, and disposal costs. Dry ice offers a superior cleaning medium when compared with traditional cleaning solutions such as pressure washing,
chemicals, and hand scraping. When implementing dry ice cleaning, bottling equipment runs more efficiently, produces less scrap and defective products, and lasts longer because components are not subjected to damaging cleaning solutions. With an environmentally responsible cleaning solution, workers are not exposed to potentially dangerous chemicals or solvents. Bottling plants save an average of $6000 per month by implementing dry ice blasting. The majority of these savings comes from reducing labor costs and reducing equipment downtime for cleaning. The Bag-In-Box (BIB) former fills a plastic bag with liquid, forms a box around the bag, and then seals the box around the bag. It is essential that the box former’s glue nozzles are cleaned regularly to ensure proper functionality. Hand scraping the dried glue is a slow and laborintensive process that can damage the nozzles. As shown below in Fig. 10.6, Cold Jet dry ice blasting removes the glue quickly while removing dust and debris from the machine at the same time, resulting in a faster clean, a reduction in labor, and an increase in production uptime.
10. PARTICULAR CO2 APPLICATIONS; CLEANING, pH CONTROL
577
10.7 WINE BARRELS
FIG. 10.6
Before and after dry ice cleaning BIB glue nozzles.
Denesters and palletizers stack and unstack trays and crates used in transporting bottles and prepare products for shipping. They get coated with grease, dirt, sticky labels, and spilled material. Pressure washing is time consuming because the machinery has to dry for 36–48 hours and the water can also damage the electronics. Cold Jet dry ice cleaning allows the equipment to be cleaned without creating additional secondary waste and does not cause damage to the electronics, photo eyes, or other delicate components. An example of cleaning the components of a denester with dry ice blasting can be seen below in Fig. 10.7.
FIG. 10.7
10.7 WINE BARRELS Barrel aging is a common wine-making practice. The wine is traditionally housed inside oak barrels where it will mature for a predetermined period of time. This process imparts oak aromas and tannin into the wine. Flavor compounds are extracted from the wood and combined with oxygen exposure. Approximately 60%–70% of a wine barrel’s flavor is extracted during the first season, leaving about 30% of the barrel’s flavor intact. When barrels are layered with a heavy tartrate buildup, the oxygenation within the barrels is reduced, thus hindering the extraction of flavor.
Before and after dry ice cleaning a denester.
10. PARTICULAR CO2 APPLICATIONS; CLEANING, pH CONTROL
578
10. CO2 CLEANING AND PH CONTROL IN THE FOOD INDUSTRY
When utilizing CO2 cleaning, 1.27 thousandths of a millimeter of wine-saturated wood is blasted off the barrel, exposing toasted oak flavors while leaving the original toast intact. By exposing the grain, the surface area of the wood is doubled, allowing the barrels to impart more oak volatiles into the wine. This increases the remaining flavor from 30% to roughly 60%. Dry ice blasting removes tartrate crystals and old wine residues, exposing the wood, allowing the barrel to breathe, and creating an environment for maximum oxygenation. CO2 cleaning can increase the lifespan of oak barrels. Traditionally, barrels last for 3–4 years before they need to be replaced. By eliminating the need to retoast barrels after cleaning, winemakers can gain at least an extra year from the barrels. At 78.51°C/109.3°F, dry ice cleaning is a proven solution for killing and removing mold spores, bacteria, and fungus. By removing a small layer of wine-soaked wood, mold spores can be removed without altering the structural integrity of the barrel. Dry ice is EPA, FDA, and USDA approved. Because the media sublimates upon
FIG. 10.8
contact, there is no secondary residue or off tastes (source: www.barrelblasting.com).
10.8 BREWING VESSELS Similar to wine barrel aging, Dogfish Brewery uses wooden tanks for aging beer, utilizing the beer’s direct contact with the wood as a method of adding a distinct flavor. The tanks are approximately 15 ft wide by 20 ft tall and made from American White Oak and Palo Santo wood. Years of distilling and aging beer has left the wood inside the tanks coated in build-up that affects the quality and flavor of the beer. The brewery tried using ozonated water to clean the tanks, but the process could not be fully implemented because it impacted the flavor of the beer. As with wine barrels, dry ice provided a solution for removing mold spores, fungus, bacteria, and other contaminants. As shown in Fig. 10.8, by removing the top layer of wood, Cold Jet dry ice cleaning allowed for contamination removal while exposing fresh wood without compromising the structure of the tanks. The rejuvenated wood helped restore the beer’s quality and flavor.
Dry ice blasting a wooden brewing tank.
10. PARTICULAR CO2 APPLICATIONS; CLEANING, pH CONTROL
10.10 DRY ICE AVAILABILITY
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10.9 COFFEE
10.10 DRY ICE AVAILABILITY
CO2 cleaning provides a multitude of benefits within coffee-roasting facilities. A key application is cleaning roasting chambers and the surrounding area. The roasting chambers are coated with carbonized oils and hardened coffee particles. The traditional method used to clean the roasting unit is using a water jet with high pressure or a wet cloth in order to protect sensitive equipment. This method can take many days to clean the equipment because the contamination accumulates in loops and corners that are hard to reach. By utilizing dry ice blasting, the cleaning time can be drastically reduced. An example of cleaning the area surrounding the roasting chambers can be seen below in Fig. 10.9.
Dry ice will begin to sublimate as soon as it is produced, so it is usually sourced from local industrial gas companies that produce it, package it for transport, and deliver it directly to the factory or job site. Dry ice can also be produced onsite with a source of liquid CO2. If remote dry ice production is needed, systems designed and packaged for easy transport can be employed. Cold Jet’s Plug & Play dry ice production hub is pictured below in Fig. 10.10. The Plug & Play system is a dry ice pelletizer contained in an ISO transportable container, allowing the ability to produce dry ice at nearly any production facility. The pelletizer can run off CO2 tanks or dewars, eliminating the need for a static CO2 tank.
FIG. 10.9
Dry ice blasting roaster chambers.
10. PARTICULAR CO2 APPLICATIONS; CLEANING, pH CONTROL
580
10. CO2 CLEANING AND PH CONTROL IN THE FOOD INDUSTRY
10.11 CONTINUOUS CLEANING Occasionally, a uniformed cleaning solution is required. Cold Jet’s Combi Systems provide a highly customizable solution made to fit within a facility’s production line. The Combi units enable partial or complete automation for integration into a production line. Combi systems are equipped with a dry ice production unit that guarantees continuous cleaning with freshly made dry ice. The automated cleaning system can also be placed in a sound-reduction chamber that allows for the control of noise as well as the extraction and filtering of air. Pictured in Fig. 10.11, the system can be operated by itself or integrated via a robotic arm into the overall control system of the plant. FIG. 10.10
Plug & play dry ice production hub.
FIG. 10.11
Combi system with robotic blasting arm.
10. PARTICULAR CO2 APPLICATIONS; CLEANING, pH CONTROL
REFERENCES
10.12 CONCLUSION Cold Jet dry ice cleaning provides a fast, dry, superior clean that improves the quality of finished goods, increases asset utilization rates, and extends equipment life. It is also environmentally sustainable because it uses recycled CO2 and reduces secondary waste streams by eliminating or reducing chemical and water use. It makes cleaning easier and more complete, and enables food and beverage production
581
facilities to quickly and easily meet strict cleaning and hygienic standards.
References http://www.airgas.com. http://www.barrelblasting.com. http://www.coldjet.com. Wilson, S., 2012. Sustainable in-machine mold cleaning using dry ice. In: Fall 182nd Technical Meeting of the Rubber Division of the American Chemical Society Inc. Cincinnati, OH. ISSN: 1547-1977.
10. PARTICULAR CO2 APPLICATIONS; CLEANING, pH CONTROL
10 CO2 Cleaning and pH Control in the Food Industry Jan Vansant*, Christian Rogiers† †
*Cold Jet LLC and VFB bvba, Leuven, Belgium Cold Jet LLC, Sr. VP Marketing, Loveland, OH, United States
10.1 INTRODUCTION CO2 blasting, also known as dry ice blasting or dry ice cleaning, is a revolutionary blasting method that uses CO2 in its solid form as a cleaning media. CO2 gas is naturally found in our environment and is commonly manufactured in four forms: blocks, slabs, nuggets, and pellets. It is moderately reactive and nonflammable. At 78.51°C or 109.3°F, carbon dioxide changes directly from its solid phase to its gaseous phase through sublimation, or from gas to a solid through deposition. The different forms of dry ice can be seen below in Fig. 10.1. Carbon dioxide plants do not actually manufacture carbon dioxide–they purify a waste stream from another process, then liquefy the gaseous product through pressurization and temperature reduction. About 90% of all CO2 used to produce dry ice is recycled as a byproduct from ammonia, natural gas, or ethanol manufacturing processes. Alternatively, carbon monoxide is manufactured and then converted into CO2 through a shift catalyst or a proprietary solution. Approximately 90% of dry ice is used as a cooling agent in a cold-chain management
Gases in Agro-food Processes https://doi.org/10.1016/B978-0-12-812465-9.00024-4
system for the food and pharmaceutical industries while the remaining 10% is used as blasting media for cleaning. The result is a dry, nonabrasive, nontoxic cleaning method with no secondary waste. Dry ice blasting is an efficient and cost-effective way for industries to maximize production capability, quality, asset utilization rates, and asset life. In some ways, Cold Jet dry ice blasting is similar to sand blasting, plastic bead blasting, or soda blasting. The media is accelerated in a pressurized air stream to impact a surface to be cleaned or prepared. CO2 blasting works because of three contributing factors: the kinetic effect, the thermal shock effect, and the thermal-kinetic effect. Kinetic Effect: The kinetic effect in the dry ice blasting process is responsible for most of the cleaning effect at ambient and normal processing temperatures. When the dry ice particles are dispensed into the compressed air stream, they are accelerated and hit the targeted surface at high speeds (approximately 340.29m/s). These high velocities cause the contaminant to crack and loosen. The kinetic effect is responsible for most of the cleaning effect, and therefore particle speed and size are important parameters of dry ice
571
# 2019 Elsevier Inc. All rights reserved.
572
FIG. 10.1
10. CO2 CLEANING AND PH CONTROL IN THE FOOD INDUSTRY
Dry ice forms.
blasting (K.E. ¼ ½ m v2). Particle speed is mainly dependent on blasting pressure and aerodynamics. It is highly influenced by factors such as nozzle type, particle size, shape, machine dimensions, and hose dimensions. Thermal Shock Effect: The low temperature of the dry ice (78.51°C/109.3°F) causes the contaminant to shrink and become brittle, aiding in its removal. The temperature gradient created between the contaminant and the substrate creates rapid microcracking of the contaminant, causing the bond between the contaminant
FIG. 10.2
material and the substrate to fail. This allows the dry ice to permeate the contaminant more effectively. The cooling is a surface effect only, and does not rapidly cool the equipment being cleaned. Thermal-Kinetic Effect: The impact energy dissipation and rapid heat transfer between the dry ice and the surface cause instantaneous sublimation of the solid CO2 into gas. As demonstrated in Fig. 10.2, CO2 expands to nearly 800 times the volume of its solid media form and lifts the contaminant from the substrate.
Dry ice sublimation.
10. PARTICULAR CO2 APPLICATIONS; CLEANING, pH CONTROL
10.2 KEY BENEFITS
10.2 KEY BENEFITS Maintaining superior hygiene standards is essential in the food industry. Cold Jet dry ice cleaning produces a superior clean that improves the quality of finished goods, increases asset utilization rates, and extends equipment life. The process utilizes the same food-grade CO2 used in carbonated beverages. Because the dry ice media sublimates upon contact, dry ice blasting is a dry process that leaves no secondary residue. Dry ice cleaning is environmentally sustainable. It utilizes CO2 that has been reclaimed from refining industries and does not contribute to the greenhouse effect. While there is no way to completely keep CO2 from entering the atmosphere (dry ice constantly sublimates at a rate of 3%–5% when it is not in use), the creation of dry ice gives the CO2 a “second life” before it is returned to the atmosphere. In dry ice cleaning, CO2 is not created—existing CO2 with its beneficial physical phase-change properties is used for cleaning. Dry ice is colorless, tasteless, odorless, and nontoxic. Utilizing Cold Jet dry ice cleaning eliminates the use of environmentally harmful cleaning chemicals and increases operator safety
FIG. 10.3
573
as it eliminates exposure to hazardous cleaning agents. Dry ice blasting supports zero landfill initiatives and helps reduce water and sanitation costs because there is no secondary waste or water left behind to clean up. As shown in Fig. 10.3, traditional methods often utilize chemicals or abrasive media. However, CO2 blasting will not cause damage to the surface being cleaned. The dry ice particles are relatively soft. Dry ice pellets were found to be 1.5–2.0 Mohs, which is soft compared to other blasting media forms. CO2 cleaning will not etch, profile, or change the dimension of a surface harder than dry ice. The low temperature of dry ice causes the contaminant layer to shrink and become brittle, which aids in removal. The temperature change, or Delta-T, created between the surface contaminant and the substrate creates rapid microcracking of the contaminant, which causes the bond between the contaminant and the underlying surface to fail. Dry ice cleaning can usually be performed while equipment is online and still at operating temperatures. Cold Jet dry ice blasting can clean equipment such as proofers, ovens, bread coolers, and bread slicers with little to no disassembly.
Cleaning method comparison.
10. PARTICULAR CO2 APPLICATIONS; CLEANING, pH CONTROL
574
FIG. 10.4
10. CO2 CLEANING AND PH CONTROL IN THE FOOD INDUSTRY
Cleaning conveyor systems with dry ice.
10.3 GENERAL FOOD INDUSTRY APPLICATIONS Conveyor systems are constantly coated in oils, waxes, seasonings, crumbs, adhesives, and sticky labels. Using water to clean conveyor systems can be a time-consuming process because electrical components need to be wrapped and water waste needs to be collected before production can resume. Removing excess water is difficult, and any excess can lead to bacterial growth and product contamination. Cold Jet dry ice cleaning is a dry process, making it the perfect solution for cleaning conveyors in the food and beverage industry because downtime for cleaning is minimized. An example of cleaning conveyor systems with dry ice can be seen below in Fig. 10.4. Labelers get dirty with dried glue, dirt, and grease. The overspray and overflow of glue can cause labeling equipment to function inefficiently. Traditional manual cleaning involves cleaning with chemicals or hand scraping, which can cause damage to tooling. These methods are slow, labor intensive and often
ineffective, leading to expensive part replacement instead of cleaning. Cold Jet dry ice blasting removes dried glue and grease quickly and easily without disassembly, providing a faster clean that reduces labor costs and increases production uptime. Dry ice cleaning does not risk damage to critical surfaces such as cutter drums, gripper drums, glue nozzles/assemblies, or conveyance equipment.
10.4 BAKING Baking facilities need to maintain clean conditions while remembering that food will come into contact with the cleaning agents. The method of cleaning can impact the taste, cooking, rising ability, and overall quality of the finished product. Because the cleaning method can severely alter the product, governments have imposed regulations on if/where chemicals can be used. Due to sanitation issues—mainly the potential for bacterial growth—and potential damage to equipment, water is not always an ideal cleaning medium.
10. PARTICULAR CO2 APPLICATIONS; CLEANING, pH CONTROL
575
10.5 SNACK FOODS
Proofers are used to control humidity to foster the fermentation of dough by yeast, which allows the dough to rise to the correct shape and size. They are often coated in dough, bread, and other baking ingredients. Manual cleaning methods are tedious and require the dough proofer to be disassembled for cleaning. Pressure washing is discouraged because the leftover water waste provides a breeding ground for bacterial growth. By utilizing dry ice cleaning, bakeries can eliminate the need for disassembly before cleaning. Proofers can be cleaned in place, without the associated waste from water blasting. Dry ice is a food grade media. At 78.51°C/109.3°F, the threat of bacterial growth is reduced. During production, waffle cone and wafer oven plates are often coated with carbon build-up, grease, and other contaminants. Manual scrubbing with wire brushes and chemicals can be time consuming, labor intensive, and costly. Cold Jet dry ice blasting can reduce downtime due to cleaning because ovens can be cleaned while they are still hot, without disassembly. Bread coolers are often caked with layers of oil, bread crumbs, and other residue. Pressure washing can strip important mineral oils from the conveyor and requires electrical components to be wrapped. Additionally, all secondary water waste needs to be collected and removed before parts can be reassembled and production can resume. CO2 blasting provides a solution that allows baking equipment to be cleaned in place, without disassembly or wrapping of electrical parts. Because the dry ice media sublimates on contact, the need to remove water residue is eliminated. The blades on bread slicers become covered with buildup from general baking ingredients. This buildup affects the sharpness of the blades, preventing the slicers from creating a clean, sharp cut. Traditional cleaning solutions such as water or steam blasting and hand wiping require disassembly. These methods are also
tedious, risk damage to blades, and are potentially harmful to workers. Cold Jet dry ice blasting allows slicers to be cleaned without disassembly, drastically reducing labor hours. It also provides a nonabrasive cleaning solution that reduces wear and tear on the blades. Bread baggers feed the bread directly from a conveyor or slicer into the bag. When using traditional methods, it takes 96 hours to clean a bagging area. With dry ice blasting, this time is reduced to 5 minutes. On average, a baking facility can pay for a dry ice blasting system in less than one year by cleaning bread baggers with dry ice.
10.5 SNACK FOODS Cold Jet dry ice cleaning enables snack food plants to more easily meet rising sanitation standards while reducing their cleaning time by 30%–80%, effectively reducing labor costs, waste materials, and downtime. Snack food facilities lower their productivity costs because equipment and tooling are cleaned in place without disassembly, minimizing downtime and avoiding unnecessary startups and reassembly. By providing a faster, nonabrasive clean, dry ice blasting reduces the time it takes to get machinery back into production. CO2 blasting saves snack food plants an average of $17,979 per month in labor costs. Additional savings occur when cleaning beneath conveyors, between conveyors, and conduits and also when cleaning packaging equipment. Ishida weighers receive finished snack foods such as potato chips, pretzels, and cheese puffs from a conveyor and measure and weigh the material for bagging. The primary components of the weigher include radial feeders and the base or weigh head. Weighers are constantly coated with oil, grease, seasoning, and crumbs, and they need to be cleaned regularly in order to continue to accurately weigh and measure materials.
10. PARTICULAR CO2 APPLICATIONS; CLEANING, pH CONTROL
576
10. CO2 CLEANING AND PH CONTROL IN THE FOOD INDUSTRY
FIG. 10.5
Dry ice blasting an Ishida weigher.
Hand scraping, wire brushing, and chemical soaking/wiping have been used to remove the hardened grease and oil. However, these methods are slow, labor intensive, and require disassembly. Cold Jet dry ice blasting can remove the contaminants quickly, resulting in lower labor costs and higher production time. With dry ice, packaging equipment is cleaned with minimal disassembly and without damage. An example can been seen above in Fig. 10.5.
10.6 BOTTLING SOLUTIONS Cleaning with dry ice allows bottling plants to clean in difficult places and maintain hygiene standards while reducing cleaning costs. Bottling plants can often reduce cleaning labor and material costs by 70% by implementing CO2 blasting. Additionally, they will also save by reducing cleaning materials, secondary water waste, and disposal costs. Dry ice offers a superior cleaning medium when compared with traditional cleaning solutions such as pressure washing,
chemicals, and hand scraping. When implementing dry ice cleaning, bottling equipment runs more efficiently, produces less scrap and defective products, and lasts longer because components are not subjected to damaging cleaning solutions. With an environmentally responsible cleaning solution, workers are not exposed to potentially dangerous chemicals or solvents. Bottling plants save an average of $6000 per month by implementing dry ice blasting. The majority of these savings comes from reducing labor costs and reducing equipment downtime for cleaning. The Bag-In-Box (BIB) former fills a plastic bag with liquid, forms a box around the bag, and then seals the box around the bag. It is essential that the box former’s glue nozzles are cleaned regularly to ensure proper functionality. Hand scraping the dried glue is a slow and laborintensive process that can damage the nozzles. As shown below in Fig. 10.6, Cold Jet dry ice blasting removes the glue quickly while removing dust and debris from the machine at the same time, resulting in a faster clean, a reduction in labor, and an increase in production uptime.
10. PARTICULAR CO2 APPLICATIONS; CLEANING, pH CONTROL
577
10.7 WINE BARRELS
FIG. 10.6
Before and after dry ice cleaning BIB glue nozzles.
Denesters and palletizers stack and unstack trays and crates used in transporting bottles and prepare products for shipping. They get coated with grease, dirt, sticky labels, and spilled material. Pressure washing is time consuming because the machinery has to dry for 36–48 hours and the water can also damage the electronics. Cold Jet dry ice cleaning allows the equipment to be cleaned without creating additional secondary waste and does not cause damage to the electronics, photo eyes, or other delicate components. An example of cleaning the components of a denester with dry ice blasting can be seen below in Fig. 10.7.
FIG. 10.7
10.7 WINE BARRELS Barrel aging is a common wine-making practice. The wine is traditionally housed inside oak barrels where it will mature for a predetermined period of time. This process imparts oak aromas and tannin into the wine. Flavor compounds are extracted from the wood and combined with oxygen exposure. Approximately 60%–70% of a wine barrel’s flavor is extracted during the first season, leaving about 30% of the barrel’s flavor intact. When barrels are layered with a heavy tartrate buildup, the oxygenation within the barrels is reduced, thus hindering the extraction of flavor.
Before and after dry ice cleaning a denester.
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10. CO2 CLEANING AND PH CONTROL IN THE FOOD INDUSTRY
When utilizing CO2 cleaning, 1.27 thousandths of a millimeter of wine-saturated wood is blasted off the barrel, exposing toasted oak flavors while leaving the original toast intact. By exposing the grain, the surface area of the wood is doubled, allowing the barrels to impart more oak volatiles into the wine. This increases the remaining flavor from 30% to roughly 60%. Dry ice blasting removes tartrate crystals and old wine residues, exposing the wood, allowing the barrel to breathe, and creating an environment for maximum oxygenation. CO2 cleaning can increase the lifespan of oak barrels. Traditionally, barrels last for 3–4 years before they need to be replaced. By eliminating the need to retoast barrels after cleaning, winemakers can gain at least an extra year from the barrels. At 78.51°C/109.3°F, dry ice cleaning is a proven solution for killing and removing mold spores, bacteria, and fungus. By removing a small layer of wine-soaked wood, mold spores can be removed without altering the structural integrity of the barrel. Dry ice is EPA, FDA, and USDA approved. Because the media sublimates upon
FIG. 10.8
contact, there is no secondary residue or off tastes (source: www.barrelblasting.com).
10.8 BREWING VESSELS Similar to wine barrel aging, Dogfish Brewery uses wooden tanks for aging beer, utilizing the beer’s direct contact with the wood as a method of adding a distinct flavor. The tanks are approximately 15 ft wide by 20 ft tall and made from American White Oak and Palo Santo wood. Years of distilling and aging beer has left the wood inside the tanks coated in build-up that affects the quality and flavor of the beer. The brewery tried using ozonated water to clean the tanks, but the process could not be fully implemented because it impacted the flavor of the beer. As with wine barrels, dry ice provided a solution for removing mold spores, fungus, bacteria, and other contaminants. As shown in Fig. 10.8, by removing the top layer of wood, Cold Jet dry ice cleaning allowed for contamination removal while exposing fresh wood without compromising the structure of the tanks. The rejuvenated wood helped restore the beer’s quality and flavor.
Dry ice blasting a wooden brewing tank.
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10.10 DRY ICE AVAILABILITY
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10.9 COFFEE
10.10 DRY ICE AVAILABILITY
CO2 cleaning provides a multitude of benefits within coffee-roasting facilities. A key application is cleaning roasting chambers and the surrounding area. The roasting chambers are coated with carbonized oils and hardened coffee particles. The traditional method used to clean the roasting unit is using a water jet with high pressure or a wet cloth in order to protect sensitive equipment. This method can take many days to clean the equipment because the contamination accumulates in loops and corners that are hard to reach. By utilizing dry ice blasting, the cleaning time can be drastically reduced. An example of cleaning the area surrounding the roasting chambers can be seen below in Fig. 10.9.
Dry ice will begin to sublimate as soon as it is produced, so it is usually sourced from local industrial gas companies that produce it, package it for transport, and deliver it directly to the factory or job site. Dry ice can also be produced onsite with a source of liquid CO2. If remote dry ice production is needed, systems designed and packaged for easy transport can be employed. Cold Jet’s Plug & Play dry ice production hub is pictured below in Fig. 10.10. The Plug & Play system is a dry ice pelletizer contained in an ISO transportable container, allowing the ability to produce dry ice at nearly any production facility. The pelletizer can run off CO2 tanks or dewars, eliminating the need for a static CO2 tank.
FIG. 10.9
Dry ice blasting roaster chambers.
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10.11 CONTINUOUS CLEANING Occasionally, a uniformed cleaning solution is required. Cold Jet’s Combi Systems provide a highly customizable solution made to fit within a facility’s production line. The Combi units enable partial or complete automation for integration into a production line. Combi systems are equipped with a dry ice production unit that guarantees continuous cleaning with freshly made dry ice. The automated cleaning system can also be placed in a sound-reduction chamber that allows for the control of noise as well as the extraction and filtering of air. Pictured in Fig. 10.11, the system can be operated by itself or integrated via a robotic arm into the overall control system of the plant. FIG. 10.10
Plug & play dry ice production hub.
FIG. 10.11
Combi system with robotic blasting arm.
10. PARTICULAR CO2 APPLICATIONS; CLEANING, pH CONTROL
REFERENCES
10.12 CONCLUSION Cold Jet dry ice cleaning provides a fast, dry, superior clean that improves the quality of finished goods, increases asset utilization rates, and extends equipment life. It is also environmentally sustainable because it uses recycled CO2 and reduces secondary waste streams by eliminating or reducing chemical and water use. It makes cleaning easier and more complete, and enables food and beverage production
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facilities to quickly and easily meet strict cleaning and hygienic standards.
References http://www.airgas.com. http://www.barrelblasting.com. http://www.coldjet.com. Wilson, S., 2012. Sustainable in-machine mold cleaning using dry ice. In: Fall 182nd Technical Meeting of the Rubber Division of the American Chemical Society Inc. Cincinnati, OH. ISSN: 1547-1977.
10. PARTICULAR CO2 APPLICATIONS; CLEANING, pH CONTROL