Fractionator ethylene/ethane

Deethanizer and ethylene fractionator (ethylene/ ethane splitter). The Cj and heavier hydrocarbons from the bottom of the demethanizer are sent to the deethanizer operated at approximately 25 atm. It is either a trayed tower or a packed column. Deethanizer overhead consists of C2 hydrocarbons and the bottom products are C3 and heaviers. 

C2 fraction without acetylene to ethylene/ethane separation... 

Studiengesselschaft Kohle m.b.H. (2) reported the effect of temperature on solubility level in supercritical gas. The solubility is highest within 20 K of the critical temperature and decreases as temperature is raised to 100 K above the critical temperature. At temperatures near the critical temperature, a sharp rise in solubility occurs as the pressure is increased to the vicinity of the critical pressure and increases further as the pressure is further increased. Less volatile materials are taken up to a lesser extent than more volatile materials, so the vapor phase has a different solute composition than the residual material. There does not seem to be substantial heating or cooling effects upon loading of the supercritical gas. It is claimed that the chemical nature of the supercritical gas is of minor importance to the phenomenon of volatility amplification. Ethylene, ethane, carbon dioxide, nitrous oxide, propylene, propane, and ammonia were used to volatilize hydrocarbons found in heavy petroleum fractions. 

Acetylene in the deethanizer overhead is hydrogenated (10) or recovered. The ethylene-ethane stream is fractionated (11) and polymer-grade ethylene is recovered. Ethane leaving the bottom of the ethylene fractionator is recycled and cracked to extinction. 

Application To produce polymer-grade ethylene and propylene by thermal cracking of hydrocarbon fractions—from ethane through naphtha up to hydrocracker residue. Byproducts are a butadiene-rich C4 stream, a Cg— Cg gasoline stream rich in aromatics and fuel oil. 

The heavier C2 stream is deethanized (7) and C2 overhead passes to the MP ethylene-ethane fractionator (9) integrated with C2 refrigeration system. The lighter C2 stream is routed directly to the ethylene-ethane fractionator (9). Polymer-grade ethylene product is sent overhead from the ethylene-ethane fractionator. Acetylene recovery may optionally be installed upstream of the ethylene-ethane fractionator (8). 

In the gas fraction, the main prodncts are methane, ethylene, ethane and propene. It is shown that by increasing the temperatnre, the propane and propene content decreases while methane and ethylene increase. 

Based on the available results, the relative fraction of ethane that reacts by the above reactions is identical regardless of the reactor used. This conclusion is further supported by the findings of this investigation and also by those of Dunkleman and Albright (7) that the overall kinetics of ethane reactions are not affected by the material of construction or by the pretreatment of the reactor even though ethylene and total coke yields are. More discussion of the kinetics of pyrolysis will be reported later in this chapter. 

Low Ethylene Ethane Ratio. Examination of the C2 fraction indicated an ethylene ethane ratio of 0.5 for the total gas, projected retorting indicies would suggest a longer residence time, or an effective temperature slightly higher than Fischer assay (18). 

The photolysis of pure methane in the solid phase and of methane in argon or krypton matrices has been examined by Ausloos et at 1236 A. The photolysis of solid methane is very similar to the gas-phase photolysis. Hydrogen and ethane are the major products, with CH4-CD4 mixtures showing an H2 and D2 richness over HD, and a predominance of d, d, d and rfg fractions in ethane. These features are indicative of molecular elimination of hydrogen followed by insertion of CH2 into methane. It was found that the smaller but significant contribution of ethane- s was greater than that of either ethane- i or d. This has been interpreted as evidence for the primary photolysis of methane into a hydrogen atom and a methyl radical. The fact that little ethane- i or is found excludes the formation of the methyl radicals by the dissociation of a hot ethane molecule after insertion by CH2. The minor products of photolysis are ethylene, propane, butanes, propene and pentanes. The presence of ethylene-[Pg.68]

Gant and Yang studied the decay of gaseous T2 in cyclopropane (cyclopropane pressure more than 100 times that of T2). The main products are tritiated cyclopropane, propane, propene, ethylene, ethane and acetylene. Table 7 gives the yields of the main products as fractions from the number of tritium atoms, incorporated into these compounds. 

A distillation process has been set up to separate an ethylene-ethane mixture as shown in Fig. P4.94. The product stream will consist of 98% ethylene and it is desired to recover 97% of the ethylene in the feed. The feed, 1000 lb per hour of 35% ethylene, enters the preheater as a subcooled liquid (temperature = — 100 F, pressure = 250 psia). The feed experiences a 20 F temperature rise before it enters the still. The heat capacity of liquid ethane may be considered to be constant and equal to 0.65 Btu/(lb)(°F) and the heat capacity of ethylene may be considered to be constant and equal to 0.55 Btu/(lb)("F). Heat capacities and saturation temperatures of mixtures may be determined on a weight fraction basis. An optimum reflux ratio of 6.1 lb reflux/lb product has been previously determined and will be used. Operating pressure in the still will be 250 psia. Additional data are as follows ... 

Charts containing plots of log K vs. log P for each of several convergence pressures are presented in the Engineering Data Book.19 Charts are presented for nitrogen, methane, ethylene, ethane, propylene, propane, i-butane, n-butane, /-pentane, n-pentane, hexane, octane, decane, hydrogen sulfide, selected binaries, and the normal boiling fractions. 

Reduced refrigeration demand via the use of an integrated heat pump on the ethylene-ethane fractionator. 

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