Flash and Laser Irradiation of Coal

Coal size Energy input, J Gas composition, mole % Ref. 

3 Coal contained 35-40% volatile matter. b Using an arc-image furnace, C2s = C2H4 + C2H6, 

In another series of experiments Friedel and coworkers268 270) studied the distribution of gaseous products from the laser irradiation of coals of various ranks and particle sizes in various atmospheres. In vacuum experiments the total gas yield varied inversely with coal rank, showing a four-fold increase between anthracite and lignite. The product gas composition as a function of volatile matter in coal is shown in Fig. 20. Yields of acetylene and hydrogen generally increased between anthracite 

When the concentrates of macerals of a high-volatile bituminous coal were irradiated with 6-J pulses from a ruby laser the total gas yield varied directly with volatile matter (13.4—55.4 rtiaf%) of the macerals273). Major gases evolved were H2, CO and C2 H2 their relative concentrations varied little among the macerals. 

---

Gases from Flash and Laser Irradiation of Coal... 

Gates from the flash and laser irradiation of Pittsburgh seam (hvab) coal were investigated to determine the action of high temperatures on coal. Temperatures in excess of 1000°C. were reached with both types of irradiation. Craters about 300 microns in diameter were produced in the coal with millisecond pulses from the laser unit rated at 1.7 joules output. Gaseous products from the laser and flash irradiations showed 21% and 8% acetylene, respectively. Diacetylene, vinylacetylene, and other products to molecular weight 130 were indicated in the mass spectrum of the gas from the laser study. The results indicated that the distributions of products obtained from the flash and laser irradiations of coal were different from that produced in high temperature carbonization. 

---