Pressurized Fluidized-bed Hydroretorting Research Articles

Catalytic hydroretorting of eastern US oil shales: CHESS process

Laboratory tests of the CHESS process were conducted using beneficiated Alabama oil shale and regenerable catalysts at 500°C and 7 MPa with 20 min shale residence time. Product oil sulfur and nitrogen contents were reduced by up to 98 and 74% respectively, compared with uncatalysed pressurized fluidized-bed hydroretorting (PFH). Operation with the catalysts reduced the density of the oil by 10% to 0.909 g cm −3 while still achieving 200% Fischer assay oil yield.

Biological treatability of selected organic constituents of PFH liquid waste

Aerobic biological treatability was demonstrated for selected compounds expected to be present in wastewater generated during retorting of Eastern Oil Shales by the pressurized fluidized bed hydroretorting (PFH) process. Phenol, methyl ethyl ketone (MEK), aniline and 4-methyl pyridine were selected because of their concentration and relative toxicity. A biological seed from a municipal activated sludge plant was acclimated to synthetic wastes containing phenol, MEK and aniline. Microorganisms did not acclimate to 4-methyl pyridine under the experimental conditions tested. Each compound was tested to determine if air-stripping was occurring under the experimental conditions. Only the air-stripping of MEK was found to occur under the conditions of the tests. The data were corrected for this effect. Experiments using batch biological reactors demonstrated that phenol, MEK and aniline were biologically metabolized when each compound was the sole source of carbon. A combination experiment demonstrated that phenol, MEK and aniline can be simultaneously metabolized in the presence of 4-methyl pyridine without any noticeable inhibition.

Correlations describing the pressurized fluidized-bed hydroretorting carbon conversions of six Eastern oil shales

A set of correlations has been developed to describe the pressurized fluidized-bed hydroretorting (PFH) carbon conversions of six Eastern oil shales. Laboratory-scale fluidized-bed and thermogravimetric data were used to relate hydroretorting conditions and organic carbon conversions to oil, gas and residue. Conversions have been found to depend on temperature, hydrogen pressure and residence time over the ranges studied of 750–865 K, 0–7 MPa H 2 and 0–30 min, respectively. Gas yield increases with increasing temperature but is independent of changes in hydrogen pressure. Oil yield increases with increasing hydrogen pressure and has different relationships to temperature for the various shales. A single mechanism has been used to describe the carbon conversions of Alabama and Tennessee Chattanooga, Indiana and Kentucky New Albany, Michigan Antrim and Ohio Cleveland shales under PFH conditions. The mechanism includes the simultaneous conversion of carbon to gas, oil and active carbon species which can form oil or remain as residue carbon. Yields are predicted over the temperature, hydrogen pressure and resistance time ranges used in PFH processing.

Environmental data from bench-scale pressurized fluidized-bed hydroretorting of Eastern oil shales

As part of a three year programme to develop the pressurized fluidized-bed hydroretorting (PFH) process for Eastern oil shales, tests were conducted in laboratory-scale batch and continuous units as well as a bench-scale unit (45 kg h −1) to generate a data base for six Eastern shales. Data were collected during PFH processing of raw Alabama and Indiana shales and a beneficiated Indiana shale for environmental mitigation analyses. The data generated include trace element analyses of the raw feeds and spent shales, product oils and sour waters. The sulphur compounds present in the product gas and trace components in the sour water were also determined. In addition, the leaching characteristics of the feed and residue solids were determined. The data obtained were used to evaluate the environmental impact of a shale processing plant based on the PFH process. This paper presents the environmental data obtained from bench-scale tests conducted during the programme.

Activated sludge studies of selected contaminants in pressurized fluidized-bed hydroretorting wastewater

Acetone, propionitrile, pyrrole, and thiocyanate were selected as representative compounds of wastewater expected from pressurized, fluidized-bed hydroretorting (PFH) of Eastern oil shales. The PFH process has been the subject of investigation for the purpose of obtaining higher oil yields from Eastern shales than has been possible using conventional retorting methods. Preliminary batch experiments illustrated that acetone, propionitrile, pyrrole, and thiocyanate are aerobically biodegradable by heterogeneous microbiological cultures. The use of three continuous-flow activated sludge reactors to further evaluate the biological treatability of the synthetic waste revealed that the compounds could be removed at hydraulic residence times of as low as 1 day. Three 1 day experiments demonstrated the biological system's capability to accept organic shock loadings without a change in effluent quality. A no-recycle reactor illustrated that the flocculent microbiological population had a high resistance to solids washout. Because a supplementary nitrogen source was not included in synthetic waste treated by the no-recycle unit, it was shown that propionitrile, pyrrole, and/or thiocyanate supplied the nitrogen necessary for biological activity.

Pressurized fluidized-bed hydroretorting of six eastern shales in batch and continuous laboratory-scale reactors

The Institute of Gas Technology has conducted pressurized fluidized-bed hydroretorting (PFH) tests of six Eastern US oil shales in batch and continuous laboratory-scale reactors. Batch tests were conducted to determine the effects of temperature (from 480 to 590 °C) and pressure (from 2.8 to 7.0 MPa) on oil yield and carbon conversions for shales from Alabama, Indiana, Kentucky, Michigan, Ohio and Tennessee. Continuous laboratory-scale unit tests were conducted with Indiana shale at similar temperatures and at pressures of 2.8 and 4.2 MPa. Carbon conversion to oil was found to increase significantly with increasing hydrogen pressure for all six shales while the relationship between temperature and oil yield was different for each shale. Carbon conversion to gas increased with increasing temperature but was generally unaffected by changes in pressure. The highest oil yield for each shale was obtained at the highest pressure tested of 7.0 MPa. PFH processing has been shown to produce in excess of 200% of the Fischer Assay oil yield for all six shales and up to 268% for one of the shales.

In-bed sulphur capture during pressurized fluidized-bed hydroretorting of Eastern oil shales

The Institute of Gas Technology is developing a pressurized fluidized-bed hydroretorting (PFH) process for the production of oil from Eastern oil shales. The sulphur present in the Eastern oil shales is converted to H 2S during hydroretorting. A solid sorbent (limestone or siderite) may be added to the PFH reactor with the oil shale to achieve in-bed desulphurization. The effects of operating conditions on the effectiveness of in-bed sulphur capture with limestone and siderite have been investigated. Reactivities of a limestone and a siderite toward H 2S were determined in experiments conducted in an ambient pressure thermogravimetric analyser. These tests were conducted in the temperature range of 480–565 °C using solid sorbents with an average particle diameter of 0.018 cm (−60 + 100 mesh). The results of thermogravimetric analysis tests indicate that both limestone and siderite should be capable of capturing a significant fraction of H 2S produced in the PFH reactor. Batch PFH tests have been conducted to determine the extent of H 2S removal with in-bed sorbents. The results of these tests confirm that a significant fraction of H 2S produced in the PFH reactor can be removed with in-bed sorbents.

Physical and thermal properties and leachability of Eastern oil shales hydroretorted in a pressurized fluidized bed

The physical and thermal properties of spent shale affect the design and characteristics of embankments used for storing the material prior to ultimate disposal. Leaching tests are used to determine if spent shale must be treated as a hazardous material for disposal. The Institute of Gas Technology and the Illinois Institute of Technology conducted tests to determine some physical and thermal properties and leaching characteristics of spent shale samples from six states in the Eastern United States. The samples were processed in the continuous, laboratory scale, pressurized fluidized bed hydroretorting (PFH) reactor at 4.2 MPa (600 psig) and a temperature of about 482 °C (900 °F). The physical and thermal properties determined included particle size distribution, permeability, compressibility, compactibility, consolidation, shear stress, cohesion and thermal conductivity. The samples of spent shale were also agglomerated with air at 1093 °C (2000 °F) to determine the effects on leachability. The results showed that the physical and thermal properties of the six spent PFH shales differ considerably. The results also showed that none of the spent shale samples exhibited any significant metals leachability under the acidic test conditions. In general, thermal agglomeration further reduced the levels of metals leached from the spent shales.

Project targets advances in oil shale processing

A $6.5 million project to apply recent advances in fluidized-bed processing to the hydroretorting of eastern oil shale is getting under way. The project, which is to be directed by the Institute for Gas Technology (IGT) under contract to the U.S. Department of Energy, will involve subcontracts with a number of universities and companies and will continue for three years. Although proceeding with little fanfare, the project is but one example of recent attempts to develop needed alternative energy technologies for the future. At the core of the program is development of a pressurized fluidizedbed hydroretorting (PFH) process designed by IGT. The proposed PFH process combines IGT's experience in both fluidization and shale retorting. IGT has been active for many years in developing coal gasification processes and, more recently, in developing processes for the utilization of eastern oil shale as an alternative energy source. The principal product of the project will be data for ...