374 



GAS. 



artificial illumination is incandescent carbon. 

 To render non-luminous hydrogen luminous, 

 carbon has to be added to it. Imitating the 

 constitution of coal-gas as nearly as possible, 

 gaseous hydrocarbons of the paraffin, olefine, 

 and aromatic series are introduced by the 

 manufacturer. Owing to the enormous de- 

 velopment of the petroleum industry, large 

 amounts of petroleum and naphtha have been 

 placed at the disposal of the gas-manufacturer 

 at a low price, and these form very advan- 

 tageous sources for the production of the hy- 

 drocarbons. Without them or some equiva- 

 lent, water-gas could not be made in compe- 

 tition with coal-gas. To-day naphtha ranges 

 in price from two to five cents a gallon. To 

 carburet 1,000 feet of water-gas, five gallons 

 of naphtha are required. When it is remem- 

 bered that the total cost of the material from 

 which 1,000 feet of gas is made is less than 

 fifty cents, the importance of cheap naphtha 

 will be evident. 



Water-gas processes can be arranged under 

 two heads regenerative and non-regenerative. 

 Two of the first-named processes may be de- 

 scribed, and one of the latter. 



The Lowe Process. All the water-gas process- 

 es are the growth of engineering experience, 

 even if, in their original conception, they rep- 

 resent inventions. They are protected by nu- 



of this cupola, or gasogen, are one or more 

 cupolas, filled with fire-brick, stacked loosely, 

 like those in a Siemens regenerator. The 

 products of combustion from the gasogen pass 

 through a pipe into the regenerative cupola 

 and heat the contents to a white heat. The 

 next step in the process is to turn off the air 

 and admit steam at the bottom of the coal in 

 the first cupola, or gasogen. At the same time 

 a small stream of naphtha, or crude petroleum, 

 is admitted to the gasogen at its top. The 

 steam rises through the hot coal and is decom- 

 posed thereby, forming carbonic oxide and 

 hydrogen. As the gas thus formed in enor- 

 mous volumes passes upward and out of the 

 gasogen it meets with the intiowing petroleum 

 or naphtha, and the vapors produced there- 

 from, and carries the rich vapors on into the 

 regenerator. The mixed gas and vapors pass 

 through the hot bricks and acquire a high tem- 

 perature. The vapor of naphtha is decom- 

 posed and converted into olefiant and other 

 light-giving gases. In the language of the gas- 

 engineer, the gas is " fixed." From the regen- 

 erating cupola it is conducted through ordinary 

 purifying and scrubbing apparatus to the gas- 

 holders. The gas-making period lasts as long 

 as the heating period. Twice or oftener in the 

 hour the valves are changed, and the steam 

 and naphtha are shut off and air is blown in, 



FIG. 1. LOWE PROCESS. 



merous patents. In the Lowe process the coal, 

 usually anthracite, is contained in a cupola or 

 blast-furnace. By blowing air through it, after 

 ignition, for from fifteen to forty-five minutes, 

 it is brought to an intense heat. By the side 



and the reverse. Thus the operation is inter- 

 mittent, .gas-making occupying only half of the 

 time. To make the process continuous two 

 sets of apparatus must be used. The operation 

 of coal-gas making is also intermittent, but to 



