Sulfur trioxide gas

Calcium oxide is heated in an environment of sulfur trioxide gas ... 

Sulfur trioxide gas is heated in the presence of sodium oxide. 

Sulfur trioxide gas dissociates into sulfur dioxide gas and oxygen gas at 1250°C. In an experiment, 3.60 moles of sulfur trioxide were placed into an evacuated 3.0-liter flask. The concentration of sulfur dioxide gas measured at equilibrium was found to be 0.20 M. What is the equilibrium constant, Kc, for the reaction ... 

Sulfur trioxide gas reacts with gaseous hydrogen fluoride to produce gaseous sulfur hexafluoride and water vapour. The value of Kc is 6.3 X 10 3. 

Sulfuric Acid. Essentially all sulfuric acid manufactured in this industry is produced by the contact process, in which SO2 and oxygen contact each other on the surface of a catalyst (vanadium pentaoxide) to form SO3 gas. Sulfur trioxide gas is added to water to form sulfuric acid. The sulfur dioxide used in the process is produced by burning elemental sulfur in a furnace. 

Anhy2drous calcium sulfoaluminate is formed by calcination of lime, gypsum and bauxite. The active expansive ingredient, C A S is formed by solid-state reaction from mixtures of compounds composed of calcium oxide, aluminum oxide, sulfur trioxide gas formed during the calcination of gypsum, and bauxite. Crystal growth of CSAs is encouraged to proceed at a slow rate to preserve the potential force of expansion for extended periods [76],... 

An evacuated 1.00-liter vessel is injected with 0.777 moles of sulfur trioxide gas, S03. The vessel is then heated to a high temperature where the S03 partially decomposes to form the products S02 and 02 in the reaction shown below ... 

Sulfur trioxide gas, one of the causes of acid rain, is produced in the upper atmosphere when oxygen reacts with sulfur dioxide gas in the reaction shown below ... 

The basic steps in the contact process are (1) production of sulfur dioxide (2) cooling and, for smelters, cleaning of the process gas (3) conversion of the sulfur dioxide to sulfur trioxide (4) cooling of the sulfur trioxide gas and (5) absorption of the sulfur trioxide in sulfuric acid.28 Figure 25.8 is a photograph of a contact process plant. A simplified diagram of a double absorption contact sulfuric acid process is shown in Fig. 25.9. Because sulfur dioxide is produced by several processes, it is convenient to separate the discussion of sulfur dioxide production from its conversion to sulfuric acid. 

Sulfur dioxide gas and oxygen gas combine in a reversible reaction to form sulfur trioxide gas. 

If the gas has not been adequately cleaned, the contact section of the plant will have continuing operating problems. Improper operation of the mist precipitators will permit acid mist to enter the contact section. This will result in corrosion and sulfate accumulation in the gas ducts, the blower, and the heat exchangers. The corrosion is particularly severe in the heat exchangers because the tube wall temperature, with hot sulfur trioxide gas in the tubes, exceeds 300 °F. The sulfate accumulation on the duct walls is normally not a serious corrosion problem but it eventually breaks loose and is carried onto the catalyst beds in the converter. This sulfate, and also any dust that may pass through the purification section, will gradually blind the catalyst beds. This reduces the conversion efficiency and increases the pressure drop through the plant. 

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