Showing papers on "Substitute natural gas published in 1978"

Process for gasification of coal to maximize coal utilization and minimize quantity and ecological impact of waste products

Abstract: Coarse, graded coal is fed to a pressurized relatively fixed bed, non-slagging gasifier from which crude gas is recovered. Fine coal is slurried in an aqueous mixture comprising the discharge from the relatively fixed bed gasifier, which discharge is composed of hydrocarbons, phenolic water and other liquids as major components and additional makeup water, if required, and the slurry is fed to a slagging, pressurized entrained flow gasifier from which additional crude gas is recovered. The two streams of gas are cleaned and then used to meet a variety of demands, including, but not limited to, gas turbine generation of electric power, manufacture of synthetic natural gas and manufacture of methanol.

Process for the manufacture of fuel gas

Abstract: An improved process is disclosed for the production of fuel gas such as synthetic natural gas from coal. A sized coal feed of larger particle size is gasified in a moving bed gasifier such as the British Gas/Lurgi slagging gasifier, and forms a methane rich synthesis gas containing heavy and light organics which is quenched to form a water phase containing dissolved phenolic and other compounds. The water phase is separated from the gas phase and insoluble organics and mixed with a second portion of the coal containing fine particles which are not suitable for moving bed gasification to form a slurry. This coal-phenolic water slurry is gasified in an entrained bed gasifier, for example, the Texaco partial oxidation process, and forms a methane lean synthesis gas. The phenol, ammonia and dissolved organics in the water phase are destroyed and converted to valuable product gas. At least part of this product gas may be blended with the moving bed product gas for further processing to produce the desired fuel gas product. The product gas from the entrained bed gasifier is also suitable for production of hydrogen, ammonia, or methanol.

Process for the production of methane-containing gases and catalyst used in process

Abstract: Steam reforming catalysts which are suitable for the gasification of hydrocarbons, particularly heavier hydrocarbons such as kerosene and gas oils, consist of calcined and reduced forms of a basic mixed carbonate of nickel, aluminium and chromium produced by coprecipitation. The catalysts are further characterized in that they have a pore size distribution such that at least 55% by volume of the pores of the calcined but unreduced catalyst which have a pore radius of 12-120A is in the range 12-30A. The catalysts are produced by coprecipitation, preferably at temperatures of not more than 60° C., by using an alkali carbonate as the precipitant and by adding the precipitant to a mixed solution of alumium, nickel and chromium III compounds. The catalysts which have good sinter and polymer resistance may be used for the production of methane-containing gases, e.g., for the production of substitute natural gas.

Economics of electricity and SNG from in situ coal gasification

Abstract: Conceptual process designs and cost estimates are presented for two potential applications of underground coal gasification: a 900 MW(e) combined-cycle electric generating plant fueled by low-Btu gas; and a substitute natural gas (SNG) plant producing 155 MMscfd of 954 Btu/scf gas. Designs were based on experimental data obtained at the Laramie Energy Research Center on subbituminous coal using the linked vertical well in situ gasification process. Respective capital investments were estimated to be $395 and $351 million in first-quarter 1977 dollars. Product prices were calculated as a function of the debt/equity ratio, the annual earning rates on debt and equity, the cost of coal, and plant factor (onstream efficiency). Using a debt/equity ratio of 70/30, an interest rate on debt of 9%, an after-tax earning rate on equity of 15%, and a coal feed cost of $5/ton, product prices were 24 mills/kWh for electricity at 70% plant factor and $2.89/10/sup 6/ Btu for SNG at 90% plant factor. Calculated overall thermal efficiencies for the two facilities were 24 and 38% respectively, based on in-place coal.

A clean coal conversion technology

Abstract: Technical feature:The Ralph M. Parsons Co. and the U.S. Dept. of Energy are developing preliminary designs and economic evaluations of commercial coal conversion facilities. The commercial designs already completed include a Fischer-Tropsch facility producing liquid hydrocarbons plus substitute natural gas by indirect coal liquefaction. More specifically, this facility will produce carbon dioxide-carbon monoxide-hydrogen syngas, which will then be purified and converted into hydrocarbon liquids. Part of the unreacted syngas will be upgraded to substitute natural gas by methanation. The Parsons design incorporates advanced technology and satisfies strict environmental requirements. Major pollution abatement efforts include: desulfurization of gases generated during coal conversion; removal of acid gases; and a combination of recycling and discharge of aqueous effluents. Of particular concern is the possible formation of carcinogenic compounds in coal tar. (2 diagrams, 1 drawing, 2 tables)

SNG from peat by the PEATGAS Process

Abstract: The total energy content of U.S. peat resources is estimated to be equivalent to 1440 quads or over 2400 billion barrels of oil. Generally, peat deposits are located in areas with no other fossil fuel resources. Therefore, for those areas, it represents a very important energy resource. The areas with large peat deposits also have plentiful water supplies, so the local water resources can easily afford conversion of peat to substitute natural gas. Under the joint sponsorship of the U.S. Department of Energy and the Minnesota Gas Company, the Institute of Gas Technology has developed the PEATGAS process for the conversion of peat to substitute natural gas having a heating value of about 960 Btu per SCF. The heart of the process consists of a two-stage PEATGAS reactor incorporating a cocurrent, dilute-phase entrained-flow hydrogasification stage followed by a fluidized-bed char gasification stage using ateam and oxygen. The overall thermal efficiency of the process is calculated to be 67% for a 250 billion Btu per day SNG plant using a 50% moisture content Minnesota peat. About 78% of the total methane produced in the plant is made in the gasifier itself. Therefore, only about 22% of the methane is made bymore » catalytic methanation. The by-products yield on a daily basis from a 250 billion Btu per day SNG plant is estimated to be 136,030 gallons benzene, 6,680 barrels fuel oil, 565 tons anhydrous ammonia, and 52 long tons sulfur. The total fuel output of such a plant is about 309 billion Btu per day.« less

Pre-methanation purification study: removal of low concentration gaseous sulfur compounds (catalyst poisons)

Abstract: Before catalytic methanation can be used for the commercial production of synthetic natural gas from synthesis gas, the problem of methanation catalyst deactivation must be solved. The nickel catalyst used is easily poisoned by sulfur compounds. It was the purpose of this program to identify and develop a viable and effective pre-methanation purification system to protect the methanation catalyst and therby promote viable coal gasification by the SYNTHANE process. A review and analysis was made of state of the art gaseous sulfur compound removal processes. On the basis of this extensive review, a system was selected for a detailed laboratory evaluation to obtain needed design data. A copper-chromium oxide impregnated activated carbon was selected as the test sorbent and evaluated for its ability to remove specified levels of H/sub 2/S, COS, CS/sub 2/ mercaptans and thiophenes. The levels used of these respective sulfur compounds was dictated by the anticipated performance of the Benfield Hot Potassium Carbonate Process selected for bulk removal of acid gases in the Synthane Process. Experimental runs were made using single component and multicomponent sulfur compound gaseous mixtures in a simulated synthesis gas. Adsorption breakthrough curves were evaluated and estimates were made of the time for breakthroughmore » to occur, and the approximate maximum values of volume of gas that could be processed/volume of carbon used. Using this data, estimates of sorbent requirements, costs, and environmental handling constraints were made for a system to be used in the 72 TPD SYNTHANE pilot plant.« less