Contact Process manufacture

A typical relay is shown in Figure 12.29(b). These relays can also be made digital to be connected to a central control system for close monitoring and control of a process. Now they can have much wider application, such as better communication and information feedback facilities, to optimize a process and maximize productivity. For more details refer to Section 13.2.. ) or contact the manufacturers. 

Note These values are only indicative and may vary with the quality of mix and process of curing etc., and differ from one manufacturer to another. For exact values, contact the manufacturer. 

To determine if you have manufactured, processed, used or stored any of the materials on the lists of covered substances, you should review material safety data sheets and labels for the products that you have. If you do not have data sheets or labels for any of your products, you should contact the manufacturer or supplier to get that information. 

Fleat transfer cements are quite useful for transferring the heat from an external tracing when attached outside of the process pipe, Figures 10-167 and 10-168. To determine the number of heat transfer steam tracers, it is important to contact the manufacturer of the heat transfer cement. The illustrations here should be considered preliminary for approximating purposes. The information/data that follows is used with permission from Thermon Manufacturing Co./Cellex Div. Except for specific conditions, most applications represent the requirements to maintain a pipe (or vessel) system temperature, not to raise or lower the temperature. 

Miles, F. D., The Manufacture of Sulfuric Acid by the Contact Process, Gurney Jackson, London, 1925. 

N2(g) + 3H2(g) 2NH3(g) AH° = —92 kj/mol Because the reaction is exothermic, heat is released as the reaction proceeds. Le Chatelier s principle predicts that the yield of ammonia is greater at lower temperatures. Just as in the contact process for manufacturing sulfuric acid, however, high yield is not the only important factor. The rate of reaction for ammonia synthesis is too slow at low temperatures. 

Steam is also used as a diluent, stripping medium, or source of vacuum through the use of steam jet ejectors. This steam actually contacts the hydrocarbons in the manufacturing processes and is a source of contact process wastewater when condensed. 

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. 

We begin our discussion with what is by far the largest volume chemical produced in the United States sulfuric acid. It is normally manufactured at about twice the amount of any other chemical and is a leading economic indicator of the strength of many industrialized nations. Since about 80% of all sulfuric acid is made by the contact process which involves oxidation of sulfur, we will examine this raw material in detail. The average per capita consumption of sulfur in the United States is a staggering 135 Ib/yr. 

The contact process was invented by Phillips in England in 1831 but was not used commercially until many years later. Today 99% of all sulfuric acid is manufactured by this method. It was developed mainly because of the demand for stronger acid. All new contact plants use interpass absorption, also known as double absorption or double catalysis. This process will be described in detail in Fig. 2.3. 

Figure 2.3 Contact process for sulfuric acid manufacture.

Late 1800s The lead chamber process for manufacturing sulfuric acid was prevalent in this period. Arsenic was a common contaminant in the pyrites used as a source of sulfur for this process. Now the cleaner contact process is used and most of the raw material is elemental sulfur. 

Sulfuric acid is manufactured by two processes namely, the chamber process and the contact process. The chamber process was discovered in 1746 and was used to produce sulfuric acid for over a century. This process was replaced hy the contact process which has a lower production cost and yields a more concentrated acid needed for most industrial applications. The chamber process is obsolete now but for historical interest it is outlined below. 

Sulfur trioxide is produced as an intermediate in manufacturing sulfuric acid by the contact process (See Sulfuric Acid). The process involves catalytic oxidation of sulfur dioxide to trioxide. 

To facilitate adoption or approval of a PAT process, manufacturers may request a preoperational review of a PAT manufacturing facility and process by the PAT team by contacting the FDA Process Analytical Technology Team at PAT cder.fda. gov. ft should be noted that when certain PAT implementation plans neither affect the current process nor require a change in specifications, several options can be considered. Manufacturers should evaluate and discuss with the agency the most appropriate option for their situation. 

Manufacture.—The world s annual output of sulphuric aeid is approximately 10 million tons, and this huge amount is supplied almost entirely by the lead chamber and contact processes. The dry distillation of green vitriol as a technical operation has now been abandoned. In Great Britain and Northern Ireland the output for the year 1928 in terms of 100 per cent, sulphuric acid and including oleum was 928,000 tons. ... 

From a consideration of the details of the ordinary contact process it will readily be recognised that the catalytic method of manufacture of sulphuric acid is capable of yielding an acid of the highest degree of purity. 

The papers in this section represent the theory and current industry practices in the separation process and in separator design. Because separation is such a basic requirement for the oil and gas industry, a wealth of information has been published concerning the process and the various design techniques used in the manufacture of separation equipment. Some of these techniques are proprietary, however, and the details of the design are not readily available. For instance. British Petroleum has done considerable design and testing of cyclone-type separation equipment in recent years with the objective of miniaturizing the equipment for use on offshore platforms. For further details on this and other proprietary equipment, one must contact the manufacturer or licensee of the equipment. 

Miles, Manufacture of Sulphuric Acid (Contact Process), vol. iv. (London, 1925), p. 120. 

Gypsum may be a potential source of sulfur and sulfuric acid. Some European plants make Portland cement and sulfuric acid from gypsum or anhydrite. In the Muller-Kuhne process, gypsum is mixed with clay and silica in quantities necessary to make cement, along with coke to reduce CaSC>4 to CaO. In equipment similar to that for portland-cement manufacture, the SOi is driven off and converted to sulfuric acid by the contact process,... 

The use of certain vanadium compounds as catalysts has been increasing. Vanadium oxy trichloride is a catalyst in making ediylene-propylene rubber. Ammonium metavanadate and vanadium pentoxide aie used as oxidation catalysts, particularly in the production of polyamides, such as nylon, in the manufacture of H>S04 by the contact process, in the production of phdialic and maleic anhydrides, and in numerous other oxidation reactions, such as alcohol to acetaldehyde, anthracene to anthraquinone, sugar to oxalic acid, and diphenylamine to carbazole. Vanadium compounds have been used for many years 111 die ceramics field for enamels and glazes. Colors are produced by various combinations of vanadium oxide and silica, zirconia, zinc, lead, tin, selenium, and cadmium. Vanadium intermediate compounds also are used in the making of aniline Mack used by the dye industry... 

SO2 + O2 1 2SO3 Pt or V205 Intermediate step in the contact process for synthesis of sulfuric acid H2S04 Manufacture of fertilizers, chemicals oil refining... 

Sulfuric acid (H2S04), the world s most important industrial chemical, is manufactured by the contact process, a three-step reaction sequence in which (1) sulfur burns in air to give S02, (2) S02 is oxidized to S03 in the presence of a vanadium(V) oxide catalyst, and (3) S03 reacts with water to give H2S04 ... 

Describe the contact process for the manufacture of sulfuric acid, and write balanced equations for all reactions. 

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