Pressure and ozone dissolution: the influence of pressure on ozone solubility in water

Pressure is one of the most direct control variables for the amount of ozone that can be dissolved in water. Those who understand how pressure influences ozone solubility can make deliberate choices about system design and production settings that maximise the available ozone concentration. The relationship between pressure and solubility is described by Henry's law: the amount of dissolved gas is proportional to the partial pressure of that gas above the liquid. For ozone water systems this means that the dissolved ozone concentration scales directly with the partial pressure of ozone in the gas phase above the water. Higher partial pressure results in more dissolved ozone per litre of water, up to the temperature-dependent saturation limit. In the practice of ozone water production, pressure plays a role in two ways. The first is the total system pressure during ozone dissolution, which determines the pressure at which the ozone gas comes into contact with the water. The second is the partial pressure of ozone specifically, which is determined by both the total pressure and the ozone concentration in the gas phase. At higher total pressure and higher ozone concentration in the gas phase, the partial pressure of ozone rises and the dissolved concentration increases. Venturi injection is a widely used method for introducing ozone into water under pressure. In venturi injection, the ozone gas is drawn in by an accelerated water flow, where the pressure drop in the venturi produces effective mixing of gas and liquid. This system achieves high transfer efficiency because the ozone gas is finely dispersed into small bubbles that offer a large contact surface. Pressure diffusion in closed tanks or pressure pipes is another approach where the water is in contact with the ozone gas under overpressure for a certain residence time. The higher the pressure and the longer the residence time, the more ozone is dissolved up to the saturation limit at the given water temperature. An important consideration is that dissolved ozone can partially outgas after pressure release. If the pressurised water quickly returns to atmospheric pressure after production, the saturation limit drops and part of the dissolved ozone can be released as gas. For cleaning systems it is therefore important to bring the ozone water to the cleaning surface as quickly as possible after production, without long residence times in pipes at atmospheric pressure. The two-cloth method is a working method that aligns well with this: by bringing ozone water directly to the surface immediately after production, loss through outgassing and decomposition is minimised. The relationship between pressure and solubility also provides reference points for comparing different systems. Systems that produce or inject ozone under higher pressure achieve a higher dissolved concentration at the same water temperature than systems operating at atmospheric pressure. This makes pressure one of the most influenceable parameters in the design of an ozone water system for professional cleaning applications. A solid understanding of the influence of pressure on solubility is the basis for system choices that maximise the available ozone concentration in the daily cleaning practice of professional cleaning companies and facility service providers who systematically work with ozone water on the shop floor A solid understanding of the influence of pressure on solubility is the basis for system choices that maximise the available ozone concentration in the daily cleaning practice of professional cleaning companies and facility service providers who systematically work with ozone water on the shop floor A solid understanding of the influence of pressure on solubility is the basis for system choices that maximise the available ozone concentration in the daily cleaning practice of professional cleaning