Light gas

The Reid vapor pressure is generally barely different from the true vapor pressure at 37.8°C if the light gas content —methane, ethane, propane, and butane— of the sample is small, which is usually the case with petroleum products. The differences are greater for those products containing large quantities of dissolved gases such as the crude oils shown in Table 4.13. 

Fig. 5. Two-stage light gas gun showing the piston and H projectile where M = propellant charge and 1 = light gas (a), before firing (b), after firing propellant charge (c), as piston nears necked-down mouth of the launch tube (d), after completion of firing cycle. Piston is removed from neck of launch...

On firings the gases from the propellant accelerate the piston that compresses the light gas in front of it. At a preestablished pressure, the projectile is propelled down the launch tube accelerated by the low molecular weight gas which follows the projectile to the mouth of the tube. The target material is placed in front of the launch tube, and appropriate instmmentation used to estabUsh the characteristics of the interface reaction between projectile and target (117-120). 

When coal is coked at a temperature of approximately 1000°C, about 70—75% of the product is coke. Nearly 20% of the product is a light gas, mostiy methane and hydrogen, that typically is used as fuel to heat the ovens. Coal tars amount to about 4% of the product and light oil or naphtha is about 1%. Ammonia is recovered in an amount equal to about 0.3% of the feed coal. The ammonia is usually converted to ammonium sulfate and sold as a fertilizer. Littie or no ammonia [7664-41-7] is produced inlow temperature carbonization (3). 

Significant products from a typical steam cracker are ethylene, propylene, butadiene, and pyrolysis gasoline. Typical wt % yields for butylenes from a steam cracker for different feedstocks are ethane, 0.3 propane, 1.2 50% ethane/50% propane mixture, 0.8 butane, 2.8 hill-range naphtha, 7.3 light gas oil, 4.3. A typical steam cracking plant cracks a mixture of feedstocks that results in butylenes yields of about 1% to 4%. These yields can be increased by almost 50% if cracking severity is lowered to maximize propylene production instead of ethylene. 

Potential Processes. Sulfur vapor reacts with other hydrocarbon gases, such as acetjiene [74-86-2] (94) or ethylene [74-85-1] (95), to form carbon disulfide. Higher hydrocarbons can produce mercaptan, sulfide, and thiophene intermediates along with carbon disulfide, and the quantity of intermediates increases if insufficient sulfur is added (96). Light gas oil was reported to be successflil on a semiworks scale (97). In the reaction with hydrocarbons or carbon, pyrites can be the sulfur source. With methane and iron pyrite the reaction products are carbon disulfide, hydrogen sulfide, and iron or iron sulfide. Pyrite can be reduced with carbon monoxide to produce carbon disulfide. 

Figure 3.8. Variation of light gas pressure versus time.

Baker, L.M. (1985). Balancing Projectiles for Light Gas Guns, Sandia National Laboratories Report SAND85-2012. 

Curtis, J.S. (1962), An Accelerated Reservior Light-Gas Gun, National Aeronautics and Space Administration, TND-1144. 

Shahinpoor, M., H.S. Lausen, J.L. Wise, J.R. Asay, C.H. Konrad, and R.D. Harday (1985), Ballistics Computer Code Manupulation for Optimal Design and Operation of Two-Stage Light Gas Guns, SNL—Solid Dynamics Department, Quarterly Report, October 1985. 

Impact velocities from about 2 to 6 kms which can produce shock pressures in the 110 GPa range, are routinely achieved with two-stage, light-gas guns. These systems are typically limited to diameters of from 12 to 25 mm. To achieve these velocities, propellant is used to accelerate a large piston which serves to compress a reservoir of helium or hydrogen gas to high pressure. The gas then accelerates the projectile over an acceleration distance of perhaps 25 m. 

Figure 4.12 continued) (c) An expansion of the inset region from (b), with the normal alkanes shown as (a-e). Other unidentified components (f-i) are presented to locate specific peaks for comparison purposes, (d) A light gas oil analysed under the same conditions as for the cycle oil, showing the same expanded region. In this case, the oil has not been ti eated in the same manner as the cycle oil, so it retains the components that were absent from the cycle oil. Peaks (a-i) are the same as those seen in (c). 

Atmospheric gas oil 520-G50T 271-343°C Light gas oil Blending into diesel fuels and home heating oils... 

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