Concentrations antifreeze

Testing corrosion inhibiting, engine coolant concentrate ( antifreeze )... 

The absorption of SO for oleum production is carried out over a relatively narrow temperature range. The upper temperature is set to provide a reasonable partial pressure driving force for the oleum concentration used. The lower practical temperature limit is the freezing point of oleums, which is high enough to be a problem in shipping and handling as well. For some oleum uses it is practical to add small amounts of HNO as an antifreeze (100). 

Many chemicals when added to water cause a freezing point depression, as shown in Table 1, and thus are termed antifreezes. The antifreeze properties of these chemicals vary widely as a function of their coUigative, or concentrative, properties. The reduction in freeze point depends both on the chemical itself and the concentration of the chemical in water. The freeze point depression increases as the antifreeze chemical is added to the water, until a characteristic concentration is achieved. Further addition of the antifreeze chemical to water will either result in insolubility or serve to increase the freezing point of the mixture, as illustrated in Figure 1. 

The coUigative properties of antifreeze chemicals may also result in boiling point elevation. As the chemical is added to water, the boiling point of the mixture increases. Unlike the freeze depression, the boiling elevation does not experience a maximum the boiling point versus concentration curve is a smooth curve that achieves its maximum at the 100% antifreeze level. The boiling point elevation can be another important characteristic for antifreeze fluids in certain heat-transfer appHcations. 

Ideally, a system for recycling spent antifreeze consists first of the removal of the deleterious contaminants such as the corrosion products, corrosive ions, degradation products, and remaining inhibitors. Then the clean fluid could be reinhibited to a known concentration of both inhibitors and glycol. 

General Motors Engineering Standards. Automotive Engine Coolant, Antifreeze Concentrate-Ethylene Glycol Type, GM 6038-M, Jan. 1971 Automotive Engine Coolant, Concentrate-Ethylene Glycol Type, GM 6043-M, Sept. 1983. 

Approximately 5% of the U.S. consumption of is in agriculture. Boron is a necessary trace nutrient for plants and is added in small quantities to a number of fertilizers. Borates are also used in crop sprays for fast rehef of boron deficiency. Borates, when apphed at relatively high concentration, act as nonselective herbicides. Small quantities of borates are used in the manufacture of alloys and refractories (qv). Molten borates readily dissolve other metal oxides usage as a flux in metallurgy is an important apphcation. Other important small volume apphcations for borates are in fire retardants for both plastics and ceUulosic materials, in hydrocarbon fuels for fungus control, and in automotive antifreeze for corrosion control (see Corrosion and corrosion inhibitors). Borates are used as neutron absorbers in nuclear reactors. Several borates, which are registered with the Environmental Protection Agency (EPA) can be used for insecticidal purposes, eg, TIM-BOR. 

Metal- Working and Hydraulic Fluids. In the preparation of fluids for metal-working and hydrauflcs, the trend has been to replace organic-based materials with aqueous-based materials. Neodecanoic acid has found apphcation in these newer fluids as a corrosion inhibitor and a viscosity improver. For example, neodecanoic acid is used in an aqueous hydrauflc fluid concentrate for corrosion inhibition and improved antiwear properties (101), in the preparation of a thickened aqueous hydrauflc fluid to reduce viscosity loss (102), and in a water-soluble metal working oil to reduce corrosion (103). In a similar vein, neodecanoic acid has been used in antifreeze concentrates for corrosion inhibition (104). 

Locomotive diesels As larger volumes of coolant are required in railway locomotives than in road vehicles, the cost of inhibition is proportionally greater. An additional factor is the possibility of cavitation attack of cylinder liners. These considerations place a restriction on the choice of inhibitors. In the past, chromates have been used at concentrations of up to 0-4%, but their use presents handling and disposal problems. Chromates cannot be used with ethanediol antifreeze solutions. A IS I borate-metasilicate at a concentration of 1 % has been used in the UK. Nitrate is added to this to improve inhibition of aluminium alloy corrosion. Tannins and soluble oils are also used, but probably to a lesser extent than in the past. The benzoate-nitrite formulation (formerly BS 3151) is effective and has been used by continental railways . ... 

Some data concerning the activity of antifreeze chemicals are presented in Table 14-1. Inspection of Table 14-1 shows that there are two different types of antifreeze chemicals, that is, liquids that are miscible over the full range of concentration with water and salts, often salts which are soluble only to a certain amount. In the case of liquids, a mixture of 50% by weight with water is given. In the case of solids, the ethylene glycol forms with water an... 

The behaviour depends on the type of LCP and can be limited or unsatisfactory with certain concentrated acids, antifreezes, bases, oxygenated gasolines, very hot water and steam, amines, methanol, and phenol. 

Alcohols. Methyl alcohol, and to a lesser extent ethyl alcohol, were used as freezing point depressants for many years. Their use now is minimal. When properly inhibited, alcohol-water solutions can be satisfactory coolants only under restricted conditions. Alcohol antifreezes fell into disuse because of their low boiling point (lower than that of water) and the danger of loss from boiling or evaporation. Alcohol volatilizes from hot surfaces much more readily than glycol coolant and can be a potential fire hazard. Methyl alcohol liquids are both flammable and poisonous. Methyl alcohol vapors are toxic when inhaled at high concentrations. 

Laws have been enacted in many states in an attempt to prevent the sale and distribution of deleterious antifreeze products, such as salt solutions or petroleum coolants. Even ethylene glycol engine coolants must be evaluated by testing and comparison of test results with specifications for engine coolant concentrate, such as ASTM D 3306. These tests ensure desired levels of antifreeze coolant concentrate and inhibitor are available to adequately protect cooling systems against freezing, boilover and corrosion (Fig. 2). 

The radiators of cars serve to cool down the engine with liquid that circulates around and pulls the heat away. The concentration of the fluid in the radiator can be changed to reflect the temperatures of the particular season. The concentration of antifreeze should be greater in the winter or cold months and less in the warmer months. 

It ll take 300 gallons of the 40 percent antifreeze to bring the concentration up to what he wants. Hope he has a large enough container ... 

The Problem The same service station owner from the previous problem still wants to make his 100 gallons of 20 percent antifreeze into 35 percent antifreeze. How many gallons of pure antifreeze will it take to raise the concentration ... 

It ll take just a little more them 23 gallons of pure antifreeze to raise the concentration to 35 percent. 

If you want to add pure antifreeze to what s in your radiator right now, to increase the concentration, you have to take some of the mixture out of the radiator, first. The radiator holds only so much fluid. So, an even more interesting problem involves removing a certain amount of what s in the radiator now and replacing it with pure antifreeze to achieve the level of concentration that you want. 

The Problem A man has a 16-quart radiator that now contains 16 quarts of 20 percent antifreeze. How much of the current mixture has to be removed and replaced with pure antifreeze to raise the level of concentration to 35 percent ... 

---