Background

Titanium was first used in chemical plant in the mid-1960’s. Its outstanding resistance to corrosion in oxidising chloride environments, sea water and other aggressive media were rapidly established. In several processes titanium was the first and only choice for effective plant performance and acceptable levels of life cycle cost.

Performance of Titanium in Various Chemical Environments

Today as shown below titanium is more widely used. Costs of material and fabrication have both stabilised and titanium equipment, properly designed can compete with most of the more common but usually less effective corrosion resistant alloys.

Table 1. Process media where titanium’s oxide film is stable (within operating boundaries).

Environment	Performance
Chlorine and chlorine compounds	a. Moist chlorine gas b. water solutions of chlorites, hypochlorites, perchlorates and chlorine dioxide c. Chlorinated hydrocarbons and oxychloro compounds
Other halogens	a. Bromine; moist gases, aqueous solutions and compounds b. Iodine; moist gases and compounds
Water	a. Fresh water, steam b. River water c. Seawater d. Water containing organisms that cause biofouling e. Water containing micro-organisms that would typically cause microbiologically influenced corrosion in other materials of construction
Oxidising mineral acids	a. Nitric b. Chromic c. Perchloric d. Hypochlorous (wet chlorine gas)
Inorganic salt solutions	a. Chlorides of such minerals as sodium, potassium, magnesium, calcium, copper, iron, ammonia, manganese, nickel b. Bromide salts c. Sulfides, sulfates, carbonates, nitrates, chlorates, hypochlorites
Organic acids	a. Acetic b. terephthalic c. Adipic d. Citric (aerated) e. Formic (aerated) f. Lactic g. Stearic h. Tartaric i. Tannic
Organic chemicals (with moisture or oxygen)	a. Alcohols b. Aldehydes c. Esters d. Ketones e. Hydrocarbons
Gases	a. Sulfur dioxide b. Ammonium c. Carbon dioxide d. Carbon monoxide e. Hydrogen sulfide f. Nitrogen
Alkaline Media	a. Sodium hydroxide b. Potassium hydroxide c. Magnesium hydroxide d. Ammonium hydroxid

Fabrication Costs

Fabrication costs for titanium pressure vessels are surprisingly lower than for some other widely used corrosion resistant alloys.