High sulfur content

Fuel sulfur content is being more closely scrutinized with each passing year. It is known that the burning of fuel sulfur can form sulfur dioxide and sulfur trioxide compounds. In combination with water, these sulfur oxides can form acidic compounds. 

The following 11 problems have been associated with burning high-sulfur-content fuel  

In fuel combustion systems, S02 and S03 can form upon the burning of fuel sulfur. When sulfur oxides combine with water vapor, acids form. This problem of acid formation and accumulation is a known phenomena and usually occurs under low-speed and load operating conditions. The acids which condense on fuel system components can initiate corrosion of valves, piston rings, and fuel injector nozzles. 

In marine fuel applications, injector deposits and the corrosive wear of piston rings have been linked to fuel sulfur and sulfur bearing acid formation. 

Engine lubricant formulators are aware of the problems associated with fuel sulfur and develop products to help combat its corrosive effect. Lubricants containing overbased calcium sulfonates and phenates are utilized to chemically neutralize the acids which form as a result of burning fuel sulfur. These oils can be effective at preventing the corrosive effects of fuel sulfur. However, the oils must be frequently changed to ensure that the acid-neutralizing effect is maintained. 

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Calcium carbide has been used in steel production to lower sulfur emissions when coke with high sulfur content is used. The principal use of carbide remains hydrolysis for acetylene (C2H2) production. Acetylene is widely used as a welding gas, and is also a versatile intermediate for the synthesis of many organic chemicals. Approximately 450,000 t of acetylene were used aimuaHy in the early 1960s for the production of such chemicals as acrylonitrile, acrylates, chlorinated solvents, chloroprene, vinyl acetate, and vinyl chloride. Since then, petroleum-derived olefins have replaced acetylene in these uses. 

Sour and sweet are terms referring to a cmde oil s approximate sulfur content, which relates to odor. A cmde oil that has a high sulfur content usually contains hydrogen sulfide, H2S, and/or mercaptans, RSH it is called sour. Without this disagreeable odor, the cmde oil is judged sweet. 

Coking coal is cleaned so that the coke ash content is not over 10%. An upper limit of 1—2 wt % sulfur is recommended for blast furnace coke. A high sulfur content causes steel (qv) to be brittle and difficult to roU. Some coal seams have coking properties suitable for metallurgical coke, but the high sulfur prevents that appHcation. Small amounts of phosphoms also make steel brittle, thus low phosphoms coals are needed for coke production, especially if the iron (qv) ore contains phosphoms. 

Health effects attributed to sulfur oxides are likely due to exposure to sulfur dioxide, sulfate aerosols, and sulfur dioxide adsorbed onto particulate matter. Alone, sulfur dioxide will dissolve in the watery fluids of the upper respiratory system and be absorbed into the bloodstream. Sulfur dioxide reacts with other substances in the atmosphere to form sulfate aerosols. Since most sulfate aerosols are part of PMj 5, they may have an important role in the health impacts associated with fine particulates. However, sulfate aerosols can be transported long distances through the atmosphere before deposition actually occurs. Average sulfate aerosol concentrations are about 40% of average fine particulate levels in regions where fuels with high sulfur content are commonly used. Sulfur dioxide adsorbed on particles can be carried deep into the pulmonary system. Therefore, reducing concentrations of particulate matter may also reduce the health impacts of sulfur dioxide. Acid aerosols affect respiratory and sensory functions. 

The use of high-sulfur-content fuels could enhance undesirable carbon-forming tendencies in the engine combustion chamber as well as result in higher amounts of corrosive sulfur oxides in the combustion gases. Mercaptans (a type of sulfur compound) cause odor problems and can attack some fuel system elastomers. Both the concentration of total sulfur compounds as well as the concentration of mercaptan sulfur compounds arc controlled in... 

Fluid coking has several characteristics that make it undesirable for most petroleum coke markets. These characteristics are high sulfur content, low volatility, poor crystalline structure, and low grindability index. 

Certain older reports [14] on the existence of extremely sulfur-rich sulfanes in mixtures of high sulfur content obtained from sodium thiosulfate and hydrochloric acid are in error since elemental sulfur was shown to be the main component besides traces of H2S [15]. 

More recently, 84 may have been identified by ESR spectroscopy of solutions of Li2S ( >6) in DMF at 303 K. The lithium polysulfide was prepared from the elements in liquid ammonia. These polysulfide solutions also contain the trisulfide radical anion ( 2.0290) but at high sulfur contents a second radical at g=2.031 (Lorentzian lineshape) was formed which was assumed to be 84 generated by dissociation of octasulfide dianions see Eq. (32) [137],... 

High sulfur content heavy crude oil may be recovered more efficiently using transition metal ions such as Ti or V and optionally carbon monoxide as steam additives (423). 

Oils C (Boscan), D (Cerro Negro), E (Athabasca) - from the class of asphaltenic-aromatic crude oils, have a high sulfur content. The first two oils coming from carbonate source rocks contain polar compounds consisting of very stable polycyclic aromatics. On the other hand, the last oil contains aromatics which are less condensed and more reactive. 

Present theories of the origin of acid rain indicate that we can limit acid rain by reducing sulfur dioxide emissions and moving to low-sulfur fuels but, only about 20% of the world s petroleum reserves are low in sulfur. Switching U.S. midwestern power plants to low-sulfur coal could cause economic problems since much of the coal from the Midwest and Appalachia has a high sulfur content. Most of the electric power generated in the Midwest uses high-sulfur coal and it would cost tens of billions of dollars to scrub the sulfur out of coal. 

Transient issues are important in transport applications and should be addressed early by testing. The challenge is to demonstrate the operation at high sulfur content over the full operating envelope of the vehicle power unit - start-up, transients, shutdown, sulfur spikes in the fuel, etc. using the same processor. 

Sulfurous acid (H SOj) can be produced by burning sulfur to form sulfur dioxide (SOj) gas and by then dissolving the gas in water to form sulfurous acid. This is the acid produced by burning coal that has a high sulfur content the gaseous sulfur dioxide by-product of combustion then combines with atmospheric water to form acid rain. ... 

H/C = atomic hydrogen-to-carbon ratio V = vitrinite content of coal VM volatile matter St = total sulfur TRM = total reactive macerals The adequacies of these reactivity correlations, expressed as a percentage of the total variation in the data set explained by the model, were 80.0%, 79.2%, and 47.5% respectively. A later paper in the series (21) concentrated on the development of reactivity correlations for a set of 26 high volatile bituminous coals with high sulfur contents, and extended the models previously developed in include analyses of the liquefaction products and coal structural features. These structural features included the usual... 

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