J. Thomas Schrodt

COMPARISON OF PORE STRUCTURE IN KENTUCKY COALS BY MERCURY PENETRATION AND CARBON DIOXIDE ADSORPTION

For four Kentucky coals, a comparison was made between pore volume distribution evaluated from CO2 adsorption isotherms calculated from the Cranston-Inkley method and the Medek method. These distributions agree in the micropore range from approximately 0.6–2.0 nm. Most of the pore structure is in the micropore range. For the mercury penetration studies a rectilinear relation is found between penetrated volume and applied pressure from approximately 0.1 MPa (1 atm) up to 345 MPa (3400 atm). Surface areas were calculated from adsorption data by the BET, Langmuir, and Dubinin-Polanyi methods.

Variations in the pore structure of oil shales during retorting and combustion

Effects of retort temperature and constant heating rates on the pore structure of two eastern US oil shales were investigated experimentally. Surface areas calculated from N2 and CO2 adsorption data were observed to decrease during the early, low-temperature retort stage as a result of pore mouth blockage due to the formation of a thermoplast, and then to increase markedly above the raw shale values at higher temperature. The effect of heating rate was insignificant. A drastic loss of surface area occurred during air combustion, accompanied by an increase in pore volume in the mesopore size range.

High-temperature desulphurization of low-CV fuel gas

Abstract Experimental results on desulphurization of synthesized low-CV fuel gas using Western Kentucky No.9 gasifier coal ash as the sorbent are presented; oxides of iron in the ash react with the hydrogen sulphide, and ferrous and ferric sulphides are formed. Fixed beds of ash, held at 1000 K, removed 99% of the hydrogen sulphide at a concentration of 1.25% and a throughput of 2000 h −1 . Increasing temperature, pressure, sulphide concentration and space velocity increased the sorption capacity of the ash markedly. In the conditions tested, results were consistent with diffusion control from laminar flow. Spent ash was regenerated by passing air through the beds, when sulphur dioxide was evolved and ferric oxide reformed. Potentials for other chemical reactions were examined by chemical equilibrium; the gases hydrogen, carbon dioxide, carbon monoxide and water react during desulphurization and their concentrations reach equilibrium. It is suggested that gasifier coal ashes having significant iron content are suitable sorbents for high-temperature desulphurization from synthetic low-CV fuel gases derived from coal.

Hydrogen production in the conversion of 2-methylbutane over a series of acid catalysts

Abstract The production of hydrogen from the conversion of 2-methylbutane was studied over a series of acid catalysts in a recirculation reactor system. Conversion of 2-methylbutane over an amorphous silica–alumina catalyst and ZSM-5 zeolite resulted in significant amounts of hydrogen. This supports a carbonium ion mechanism with a penta-coordinated carbonium ion intermediate. The conversion of 2-methylbutane over the USY zeolite and sulfated zirconia did not result in hydrogen being produced thus supporting the bimolecular carbenium ion mechanism.

Diffusion and adsorption in microporous solids: Measurement of effective diffusivities in coal

Abstract The unsteady-state diffusion and adsorption of carbon dioxide was examined using the unsteadystate diffusion equation which included an additional term to account for the adsorption. This allowed a theoretical prediction of the uptake of carbon dioxide which could be compared with the experimental uptake in a static volumetric adsorption device. The solution of this equation also allowed the determination of a diffusion parameter characteristic of each coal. The long equilibrium times experienced experimentally were predicted theoretically by the solution of this equation. Also, the diffusion parameter appears to be a function of the surface area, increasing with increasing surface area.

Design and cost optimization of a hot fuel gas desulfurization process

Abstract A high temperature gas desulfurization process is proposed that effectively uses the iron oxides in the waste ashes from coal gasifiers to react with and sorb the H 2 S, COS, and CS 2 , in coal-derived fuels. The process is carried out at 1033 K and 2.22 MPa in packed bed reactors. Sulfided ash sorbents may be repeatedly regenerated to produce a 30/70 molar mixture of S 2 and SO 2 , suitable for complete reduction to elemental sulfur or sulfuric acid manufacture. An optimization theory predicts the use of very shallow bed reactors, packed to 0.61 meters, operating in a cyclic sequence where the onstream time is only 0.37 hours. This markedly reduces the capital and operating costs. A plant treating 1.22 MM SCMH of 0.63 mole percent H 2 S ladened fuel gas is estimated to have a 1981 cost of

Deactivation of Hydrodesulfurization Catalysts under Coal Liquids. 2. Loss of Hydrogenation Activity Due to Adsorption of Metallics

7.638 million and an annual operating cost of

Deactivation of Hydrodesulfurization Catalysts under Coal Liquids. 1. Loss of Hydrogenation Activity Due to Carbonaceous Deposits

5.229 million. A modular plant for recovery of byproduct SO 2 , as H 2 SO 4 is estimated to cost an additional

Simultaneous heat and mass transfer from multicomponent condensing vapor-gas systems

11.38 million but shows an annual before-tax profit of

Microcharacterization of micron/submicron fly ash from a pulverized‐dry‐coal‐burning power plant

10.46 million based upon a selling price of