Wulff process

WulffProcess. The regenerative technique is best exemplified by the Wulff process, Hcensed by Union Carbide Corp. The furnace consists basically of two masses of high purity alumina refractory tile having cylindrical channels for gas flow and separated by a central combustion space as shown in Figure 10. Its cychc operation has four distinct steps, each of approximately 1 min in duration, the sequence being pyrolysis and heat in one direction followed by pyrolysis and heat in the other direction. Continuity of output is achieved by paired installations. 

Demonstration of the technical feasibility of producing mixtures of acetylene and ethylene by pyrolysis of hydrocarbons (Wulff process or Kureha process) has led to the manufacture of vinyl chloride from such mixtures. The acetylene component reacts selectively with hydrogen chloride to form vinyl chloride, the residual ethylene is converted to dichloroethane, and the latter is cracked to vinyl chloride, with the resulting hydrogen chloride being recycled. However, this type of process has not achieved the industrial importance of the all-ethylene type of process. 

The Wulff process, which is in operation in Europe and South America with varying degrees of success, uses twin regenerative furnaces for cracking light petroleum fractions. The mixed gas product from the furnace is first combined with HC1, which reacts with the acetylene to form VCM. Ethylene then reacts with chlorine to form EDC. An EDC cracking process converts EDC to VCM and HC1, and HC1 is recycled to react with the acetylene in the mixed gas product. 

The Kureha process, used in Japan, employs flame cracking of naphtha or, in some cases, heavier fractions. The treatment of the mixed gas is essentially the same as that described for the Wulff process. 

In the case of a solid heat carrier, the preheated feedstock is placed in contact with a refractory mass raised to a hi temperature. Cracking lowers the temperature and generates coke deposits that must be removed. The state of the solid and the inifiai operating condidons are restored by combustion. These operations can take place m the same reactor c> clically on a hxed r ractory (Wulff process) or in distinct units in which the solid exists in the form of moving or fluidized particle beds. In this case the hydrocarbon feedstock is injected in the combustion gases. 

Derivation (a) By the action of water on calcium carbide (b) by cracking petroleum hydrocarbons with steam (Wulff process), or natural gas by partial oxidation (BASF process) (c) from fuel oil by modified arc process. 

Wulff process. Production of acetylene by treating a hydrocarbon gas with superheated steam in a regenerative type of refractory furnace at 1148-1371C. Contact times are very short. Acety-... 

The original method of making acetylene by the action of water on calcium carbide was abandoned when more efficient methods of synthesis became available. One of those methods, known as the Wulff process, involves the cracking of hydrocarbons from petroleum. In this process, liquid petroleum, which consists of many different kinds of hydrocarbons, is heated with very hot steam, causing the hydrocarbons to break apart ( crack ) into smaller compounds. Acetylene is one of these compounds. 

A snag was that these companies now had to dispose of hydrogen chloride. The most elegant solution was to react this with acetylene in a separate stage, to give what became known as the Balanced Process. This scheme became a driving force for naphtha cracking to mixtures of ethylene and acetylene, as exemplified by the Wulff process. 

Wulff process A process used for the production of acetylene (ethyne) by the crackiiig of a saturated aliphatic hydrocarbon gas with superheated steam in a high-temperature furnace. The gas is first heated to around 1,300°C and thenpassed to a refractory brickteac-tor operating at 400"C. It is named after its American inventor R. G. Wulff who developed it in 1927. 

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