Development of advanced, continuous mild gasification process for the production of co-products

The current objective of the University of North Dakota Energy and Environmental Research Center (EERC) mild gasification project is to optimize reaction char and marketable liquids production on a 100-lb/hr scale using Wyodak subbituminous and Indiana No. 3 bituminous coals. Tests performed using the EERC 100-lb/hr process development unit (PDU) include a refractory-cure (Test P001), a test using petroleum coke (Test P002), and tests using Wyodak and Indiana coals. The reactor system used for the 11 PDU tests conducted to date consists of a spouted, fluid-bed carbonizer equipped with an on-line condensation train that yields three boiling point fractions of coal liquids ranging in volatility from about (77{degrees}--750{degrees}F) (25{degrees}--400{degrees}C). The September--December 1990 quarterly report described reaction conditions and the bulk of the analytical results for Tests P010 and P011. This report describes further P010 and P011 analytical work, including the generation of simulated distillation curves for liquid samples on the basis of sulfur content, using gas chromatography coupled with atomic emission detection (GC/AED) analysis. 13 figs., 3 tabs

Hot-Gas Filter Testing with a Transport Reactor Development Unit

The objective of the hot-gas cleanup (HGC) work on the transport reactor demonstration unit (TRDU) located at the Environmental Research Center is to demonstrate acceptable performance of hot-gas filter elements in a pilot-scale system prior to long-term demonstration tests. The primary focus of the experimental effort in the 2-year project will be the testing of hot- gas filter elements as a function of particulate collection efficiency, filter pressure differential, filter cleanability, and durability during relatively short-term operation (100-200 hours). A filter vessel will be used in combination with the TRDU to evaluate the performance of selected hot- gas filter elements under gasification operating conditions. This work will directly support the Power Systems Development Facility utilizing the M.W. Kellogg transport reactor located at Wilsonville, Alabama and indirectly the Foster Wheeler advanced pressurized fluid-bed combustor, also located at Wilsonville and the Clean Coal IV Pinon Pine IGCC Power Project. This program has a phased approach involving modification and upgrades to the TRDU and the fabrication, assembly, and operation of a hot-gas filter vessel (HGFV) capable of operating at the outlet design conditions of the TRDU. Phase 1 upgraded the TRDU based upon past operating experiences. Additions included a nitrogen supply system upgrade, upgraded LASH auger and 1807 coal feed lines, the addition of a second pressurized coal feed hopper and a dipleg ash hopper, and modifications to spoil the performance of the primary cyclone. Phase 2 included the HGFV design, procurement, and installation. Phases 3 through 5 consist of 200-hour hot-gas filter tests under gasification conditions using the TRDU at temperatures of 540-650{degrees}C (1000-1200{degrees}F), 9.3 bar, and face velocities of 1.4, 2. and 3.8 cm/s, respectively. The increased face velocities are achieved by removing candles between each test

Development of an advanced, continuous mild gasification process for the production of co-products

The primary objective of the EERC/AMAX Mild Gasification project is to commercialize a process that will produce several value-added products from a high-sulfur midwestern bituminous or a low-sulfur subbituminous coal. Indiana No. 3 and Wyodak coals are being tested in a 100-lb/hr process development unit (PDU) that has undergone shakedown testing and is undergoing parametric testing. This unit will provide the engineering data for use in determining the technical and economic data required for the design of a commercial-scale mild gasification plant. This report discusses results of carbonizer tests, char upgrading and char separations. 12 figs., 16 tabs

Development of an advanced, continuous mild gasification process for the production of co-products

Research continued on continuous mild gasification for the production of co-products. Work performed during the quarter included the refractory cure of the carbonizer, and then shakedown of the carbonizer, water quench system, and char removal system. Construction continued on the tar/oil quench system. Sulfur capture tests carried out at AMAX included iron oxide sorbent scouting studies. 3 tabs

Development of an advanced, continuous mild gasification process for the production of co-products

Prior to disassembly of the CFBR, accumulated tar residue must be removed from the reactor, piping and tubing lines, and the condenser vessels. Based on experience from the CFBR mild gasification tests, lacquer thinner must be pumped through the unit for at least one hour to remove the residual tar. The lacquer thinner wash may be followed by a water wash. The CFBR will be disassembled after the system has been thoroughly flushed out. The following equipment must be disassembled and removed for storage: Superheater; Water supply pump; Coal feed system (hopper, auger, ball feeder, valves); Reactor; Cyclone and fines catch pot; Condensers (water lines, glycol bath, condenser pots, valves); and Gas meter. After the process piping and reactor have been disassembled, the equipment will be inspected for tar residues and flushed again with acetone or lacquer thinner, if necessary. All solvent used for cleaning the system will be collected for recycle or proper disposal. Handling and disposal of the solvent will be properly documented. The equipment will be removed and stored for future use. Equipment contaminated externally with tar (Level 4) will be washed piece by piece with lacquer thinner after disassembly of the PRU. Proper health and safety practices must be followed by the personnel involved in the cleanup operation. Care must be taken to avoid ingestion, inhalation, or prolonged skin contact of the coal tars and lacquer thinner. Equipment contaminated internally by accumulation of residual tar or oil (Level 5) will be flushed section by section with lacquer thinner. The equipment will be washed with solvent both before and after disassembly to ensure that all tar has been removed from the piping, pumps, gas quench condensers, light tar condensers, and drain lines. The coal tars wig be separated from the solvent and incinerated

Development of an advanced, continuous mild gasification process for the production of co-products

The char produced in the 100-lb/hr process development unit has been magnetically cleaned by AMAX and returned to the Energy and Environmental Research Center (EERC). The final calcining step of the process is currently being performed in the 4-lb/hr continuous fluidized-bed reactor (CFBR). The liquid products generated by the PDU have been collected and split into usable fractions and fractions to be discarded. Samples of the coal-derived liquids have been sent to Merichem Corporation of Houston and Koppers Industries of Pittsburgh for determination of their usefulness as chemical feedstock for the production of cresylic acids and anode-grade-binder pitch. The technical and economic assessment performed by Xbi and J.E Sinor Consultants has been completed. The briquette testing being conducted at the EERC has produced high quality briquettes using a number of binder agents. The next step in the test matrix will include the use of coal-derived liquids from the PDU as the binder. An additional coal has been added to the mild gasification test matrix. AMAX recently acquired two eastern low-sulfur bituminous coals and suggested that a limited test schedule be conducted to determine the suitability of these coals for the mild gasification process. The sulfur levels in the raw coals are below the target levels suggested by the steel industry for metallurgical coke use. To date, it has not been possible to reach these goals using the high-sulfur Illinois Basin coals tested

Development of an advanced, continuous mild gasification process for the production of co-products

The principal finding of this study was the high capital cost and poor financial performance predicted for the size and configuration of the plant design presented. The XBi financial assessment gave a disappointingly low base-case discounted cash flow rate of return (DCFRR) of only 8.1% based on a unit capital cost of $900 per ton year (tpy) for their 129,000 tpy design. This plant cost is in reasonable agreement with the preliminary estimates developed by J.E. Sinor Associates for a 117,000 tpy plant based on the FMC process with similar auxiliaries (Sinor, 1989), for which a unit capital costs of$938 tpy was predicted for a design that included char beneficiation and coal liquids upgrading--or about $779 tpy without the liquid upgrading facilities. The XBi assessment points out that a unit plant cost of$900 tpy is about three times the cost for a conventional coke oven, and therefore, outside the competitive range for commercialization. Modifications to improve process economics could involve increasing plant size, expanding the product slate that XBi has restricted to form coke and electricity, and simplifying the plant flow sheet by eliminating marginally effective cleaning steps and changing other key design parameters. Improving the financial performance of the proposed formed coke design to the level of a 20% DCFRR based on increased plant size alone would require a twenty-fold increase to a coal input of 20,000 tpd and a coke production of about 2.6 minion tpy--a scaling exponent of 0.70 to correct plant cost in relation to plant size