How the Liquid CO2 Cleaning Process Works
Traditional drycleaning systems use perc or petroleum-based chemicals as the primary cleaning solvent-with additives and detergents. Wetcleaning utilizes water as its primary solvent. The liquid CO2 process employs liquid CO2 as the primary solvent, with recyclable cleaning agents.
Carbon dioxide is a naturally occurring and generally benign substance. At room temperature, CO2 can exist in the form of a gas and is therefore used to carbonate soft drinks and other beverages. In solid form, carbon dioxide is known as dry ice. At room temperature, CO2 can also exist as a liquid if kept in a closed system at an elevated pressure. Liquid CO2 has a gas-like consistency and a low surface tension allowing it to function as a very effective cleaning medium when combined with detergents.
The Traditional CO2 system uses a large conventional rotating basket with a detergent system. The system utilizes a specially designed, 55-pound capacity machine that houses liquid CO2. It is similar to today's front-load, mechanical action machines and features gentle wash and extract cycles.
A detergent system (containing patented cleaning agents) enhances the cleaning ability of the liquid CO2, allowing it to remove soils from the garments. After the cleaning cycle, the machine pulls the mixture of liquid CO2 and cleaning agents (i.e., the wash fluid) away from the clothes and then cleans (through our two in-cycle stills) and reuses the CO2. The Traditional CO2 process does not require heating of the clothes and is therefore gentle to fabric.
Specifically, the Traditional CO2 System works in the following stepwise fashion:
Approximately 50 pounds of garments are placed inside a large rotating basket in the machine and the door is closed, sealing the system. Vacuum is applied to remove the majority of the air in the system and CO2 gas is added to pressurize the wash tank.
Liquid CO2 is then added from the storage tank along with the detergent system in order to form the wash fluid. The clothes are agitated for a pre-set time period and with a selected degree of agitation depending on the nature of the garments (e.g., delicate, normal, and heavy cycles). It then passes through a carbon filter and returns to the wash tank. At this point, the wash cycle is complete.
The liquid CO2 and detergent mixture (i.e., the wash fluid) is pumped out of the wash tank to the storage tank. The excess wash fluid (that fluid left clinging to the garments) is further removed by a spin extract cycle. All of our wash fluid is then cleaned via a dual in-cycle distillation process that removes excess dirt and detergent. The residue from the distillation process is automatically eliminated from the machine and collected for recycling. Carbon dioxide gas is removed from the wash tank using a compressor and the gas is sent back to the storage tank for reuse. The Traditional CO2 system is able to efficiently convert CO2 from a gas to a liquid, thereby permitting 98 percent of the CO2 to be recycled. A nominal amount (10 lbs) of CO2 gas is then vented to the atmosphere.
After a cycle time of 35 minutes, the cleaned garments are removed from the wash tank.