Showing papers on "Pyrolysis published in 1976"

Pyrolysis process for solid wastes

Abstract: A process for the recovery of chemical values from waste solids, wherein shredded waste solids are intermixed with hot char and a carrier gas in turbulent flow and passed through a pyrolysis zone under turbulent conditions at a temperature ranging from about 300° F. to about 2000° F., with zone residence time of under 10 seconds, with subsequent segregation and recovery of volatilized organic chemical values, char and inorganic chemical values therefrom.

Solid waste disposal system

Abstract: There is provided a system for segregating through comminution and classification solid waste into ferrous metal, inorganic, and organic fractions. The inorganic fraction is further classified into aluminum and glass fractions. The organic fraction is further comminuted, dried and fed to a pyrolysis system where it is converted to gas for use in drying the organic material for feed to the pyrolysis system, pyrolytic oils and char. The principal saleable products recovered are char, pyrolytic oils, glass, aluminum, and ferrous metal.

Simultaneous gasification of coal and pyrolysis of organic solid waste materials

Abstract: Gaseous fuels are produced by a process which involves simultaneous gasification of coal and pyrolysis of organic solid waste materials in a pollution-free conversion system. According to this process, a mixture of coal and organic solid waste materials is fed to the top of a reaction vessel such as a vertical shaft furnace or a blast furnace, wherein the feed is dried by heat exchange with the gases rising from the lower section of the reactor. Steam and an oxidant gas containing at least 75 volume percent oxygen are introduced to the bottom of the reactor for partially combusting coke and char in a partial combustion zone thereby providing the thermal driving force for the reactions in the reactor. The organic solid waste materials are pyrolyzed and the volatile components of the coal destructively distilled simultaneously in the presence of hydrogen in a pyrolysis and coking zone of the reactor wherein the organic solid waste materials are converted into char and the coal is converted into coke. The char and coke are reacted with oxygen and steam in the partial combustion zone. The descending inorganic materials are fused and the fused slag and molten metals are tapped from the bottom of the reactor. The gaseous products are removed from the top of the furnace and subjected to a product recovery section to remove the undesirable components. The ratio of hydrogen to carbon monoxide can be varied over a wide, commercially important range, by feeding secondary steam to a high temperature reaction zone intermediate the partial combustion zone and the pyrolysis and coking zone. Depending upon the ratio of hydrogen to carbon monoxide produced, the gaseous products can be used as fuel or as a synthesis gas for the production of methanol or methane. Gaseous product containing larger quantities of methane may be produced by maintaining the reactor at elevated pressures during the process.

Pyrolysis of carbonaceous materials with solvent quench recovery

Abstract: In a continuous process for recovery of values contained in a solid carbonaceous material, the carbonaceous material is comminuted and then subjected to flash pyrolysis in the presence of a particulate heat source to form a pyrolysis product stream containing a carbon containing solid residue and volatilized hydrocarbons. After the carbon containing solid residue is separated from the pyrolysis product stream, values are obtained by condensing volatilized hydrocarbons. The particulate source of heat is formed by oxidizing carbon in the solid residue. Apparatus useful for practicing this process are disclosed.

Pyrolysis with cyclone burner

Abstract: In a continuous process for recovery of values contained in a solid carbonaceous material, the carbonaceous material is comminuted and then subjected to flash pyrolysis in the presence of a particulate heat source over an overflow weir to form a pyrolysis product stream containing a carbon containing solid residue and volatilized hydrocarbons. After the carbon containing solid residue is separated from the pyrolysis product stream, values are obtained by condensing volatilized hydrocarbons. The particulate source of heat is formed by oxidizing carbon in the solid residue and separating out the fines.

Evolution of nitrogen and other species during controlled pyrolysis of coal.

Abstract: An experimental and theoretical investigation of coal pyrolysis focused on determination of species evolved from single coal particles and on the rates of mass evolution as functions of temperature, heating rate and coal composition. Species measured were CH 4 , CO, CO 2 , C 2 H 2 , C 2 H 4 , C 2 H 6 , HCN and NH 3 . Total mass evolved was compared to total nitrogen evolved for various pyrolysis temperatures. The former was strongly coal composition dependent, while the latter was not. About half of the total volatiles and 85% of the nitrogeneous species do not evolve as the light gases listed above. A new non-gravimetric method for determination of time resolved volatilization rates produced data that compared well to a mechanistic volatilization model in which physical processes inside the particle were described. Fluid flow within a coal particle was found to be important in determining overall gas evolution rates. The results support the hypothesis that, during combustion, nitrogeneous species are evolved late in the volatilization sequence, with a low escape velocity at the particle surface.

Analysis of mixtures by collisional activation spectrometry: pyrolysis products of deoxyribonucleic acid.

Abstract: Six major components of a mixture of the pyrolysis products of deoxyribonucleic acid have been analysed by combined low energy electron impact and collisional activation spectra. The method allowed the assignment of the structures of the different components in the complex mixture without prior separation.

Hydrocarbon catalytic cracking process

Abstract: An improved hydrocarbon catalytic cracking process which comprises introducing tin into the cracking zone so as to maintain a volume ratio of carbon dioxide to carbon monoxide in the gaseous effluent from the catalyst regeneration zone of at least 3.0.

Toxicity of thermal degradation products of polyethylene and polypropylene

Abstract: Pyrolysis, thermo-oxidation and combustion of polyethylene and polypropylene were studied and the products of these thermal degradation processes were identified by means of gas chromatography and gas chromatography-mass spectrometry. The individual products of thermal degradation were evaluated for their toxicity and a conclusion on presumed toxic effect of the combustion products of the polymers studied has been drawn.

Flash Pyrolysis of 4-Arylmethylidene-oxazolones and -isoxazolones. A Versatile Synthesis of Arylacetylenes. Preliminary communication

Abstract: Flash pyrolysis of 4-benzylidene-2-phenyl-5(4H)-oxazolone (1) yields carbonmonoxide, benzene, biphenyl, diphenylacetonitrile, and 2,3-diphenylsuccinonitrile; N-benzoylphenylketenimine is implicated as the primary intermediate. The flash pyrolysis of 4-arylmethylidene-3-methyl-5(4H)-isoxazolones (3) yields carbon dioxide, acetonitrile, and phenylacetylenes substituted by alkoxy, chloro, dimethylamino, and hydroxy groups, in yields of 45–95%. Arylmethylidenecarbenes are implicated as intermediates.

Process for the production of hydrocarbons from coal

Abstract: Coal is liquefied by treatment with a hydrogen-donor solvent and gaseous hydrogen, a heavy bottoms product boiling primarily in excess of about 1000° F. is recovered, and this bottoms product is then pyrolyzed with fresh coal to produce surprisingly high yields of liquid product. The coke formed during the pyrolysis step may be gasified to generate hydrogen for use in the liquefaction operation and additional gas which can be employed as a fuel or upgraded for other uses.

Loop pyrolysis process for organic solid wastes

Abstract: Particulate organic solid waste is pyrolyzed in the presence of an inert particulate source of heat and a carrier gas in a pyrolysis reactor to form a carbon containing solid residue of pyrolysis, pyrolytic oils and gases. The particulate source of heat and carbon containing solid residue of pyrolysis are separated from the product stream. The particulate source of heat and carbon containing solid residue of pyrolysis are transported to a combustion zone where through partial or total combustion. The particulate source of heat is reheated to a temperature requisite for feed to the pyrolysis reactor with attendant generation of additional particulate source of heat.

Determination of branching in polyethylene and poly(vinyl chloride) using pyrolysis gas chromatography

Abstract: A series of polyethylenes (PE), reduced poly(vinyl chlorides), and precursor poly(vinyl chloride) (PVC) systems were studied by pyrolysis–gas chromatography (PGC) and by pyrolysis–hydrogenation–gas chromatography (PHGC). The branch content of these polymers has been interpreted on the basis of previously established literature information. Low-density PE (LDPE) was found to contain a significant number of ethyl branches. The pyrolysis results on an LAH-reduced PVC series gave significant insight on PVC microstructure. It was determined that the short-chain branches in PVC are mainly one carbon long. Some ethyl side chains and virtually no butyl branches were found in this experimental PVC series. The effect of chain branching on the pyrolysis of PVC is to increase fragmentation. The benzene/toluene ratio, along with relative amounts of benzene and naphthalene formed, may be used to indicate the relative degree of branching in this system. The application of PGC and PHGC have thus been shown to successfully extend analytical work on PE and PVC and to provide microstructural information.

Studies of the pyrolysis of diethylzinc by the toluene carrier method and of the reaction of ethyl radicals with toluene

Abstract: The thermal decomposition of diethylzinc in a toluene carrier system has been studied over the temperature range of 669 to 762 K, and percent decomposition of 3.8 to 97.2%. The decomposition occurs by a two step mechanism, the second step rapidly following the first,The overall progress of the reaction was followed by determination of the residual diethylzinc by hydrolysis followed by analysis for zinc by atomic absorption. In selected runs two additional methods were used: (i) measurement and analysis of the gas evolved during the hydrolysis and (ii) full analysis of all pyrolysis products involving the C2H5 group.In the absence of zinc oxide the decomposition is essentially homogeneous andor −205 000/19.15T if the activation energy is expressed in joules rather than calories. The presence of zinc oxide causes marked catalysis of the overall decomposition but does not appear to affect reaction 3 or reaction 6.Reaction 6 is in a strongly pressure dependent region and is based on very limited data.

Chapter III. Gas-Liquid Chromatographic Chemotaxonomy

Abstract: Publisher Summary Gas-liquid chromatographic chemotaxonomy (GLC-chemotaxonomy) has only recently appeared in the microbiological literature. Traditional chemotaxonomy employs such well-known techniques as cell-wall analysis DNA base ratios and polyacrylamide gel electrophoresis of protein extracts. GLC offers the chemical microbiologist two advantages: (1) extremely low concentrations for detection of most substances and (2) rapid analysis. It also has the disadvantage that absolute identification is rarely possible without resorting to the use of ancillary techniques. Under conditions of linear ideal chromatography, molecules of the substance to be analyzed after injection on to a gas chromatographic column would instantly partition among the moving gas phases. GLC has been used as a chemotaxonomic tool in numerous ways. The main GLC-chemotaxonomic methods have been the (1) analysis of fermentation end-products, (2) analysis of structural and other components of microbial cells, (3) pyrolysis gas-liquid chromatography, and (4) analysis of body fluids for detection of microorganisms. Pyrolysis gas-liquid chromatography (PGLC) is a technique intended to overcome the sometimes-limiting requirement of conventional GLC for volatility in the compounds to be separated by thermally degrading prior to analysis. Regardless of the apparatus used for pyrolysis, the nature of the pyrolysis products changes markedly with changing pyrolysis temperature, and the technique is frequently classified into three categories according to pyrolysis temperature: (1) mild pyrolysis, (2) medium pyrolysis, and (3) high temperature pyrolysis.

Process and apparatus for rapid pyrolysis of carbonaceous materials

Abstract: Carbonaceous materials are rapidly pyrolyzed by feed of the carbonaceous material at a high velocity tangentially to a cyclone reactor-separator while introducing a high velocity stream of a particulate source of heat into the cyclone reactor-separator at an angle inclined to the path of travel of the carbonaceous material. The cyclone reactor-separator induces separation of solids consisting of the particulate carbon containing solid residue of pyrolysis and particulate heat source from a vapor stream which includes condensible and non-condensible hydrocarbon products of pyrolysis. The particulate source of heat and solid particulate carbon containing residue of pyrolysis are transported to a cyclone burner and heated by partial combustion to a temperature suitable for feed to the cyclone reactor-separator. Rapid pyrolysis maximizes the yield of middle boiling hydrocarbons and olefins.

Toxicity of pyrolysis and combustion products of poly‐(vinyl chloride)

Abstract: The pyrolysis and combustion products of poly-(vinyl chloride) and those of some of its polymer, especially of vinyl chloride with vinylidene chloride, were analysed using gas chromatography and gas chromatography mass spectrometry. The toxic effect of the individual products on the human organism was evaluated and presumed total toxicity of the poly-(vinyl chloride) combustion products (0.3g PVC products per m3) was determined.

The thermal decomposition of some polyurethane foams

Abstract: Polyurethanes exposed to fire conditions might generate decomposition products which would be responsible for a significant part of the toxicity of the fire gases. Polyurethanes have been prepared from a commercial mixture of tolylene-2, 4- and 2,6-di-isocyanates, pure tolylene-2,4-di-isocyanate, pure tolylene-2,6-di-isocyanate and pure m-phenylene di-isocyanate. All polymers except that prepared from tolylene-2,6-di-isocyanate were obtained as flexible foams. When each polyurethane was heated at 300°C in a stream of nitrogen, a sublimate was obtained. The sublimates were all apparently polymers derived from the di-isocyanate rather than from the diol constituents of the polyurethanes. Pyrolysis of these materials at high temperatures (800–1000°C) led to similar mixtures of volatile products: at 1000°C the most abundant nitrogenous product, in each case, was hydrogen cyanide.

Coal liquefaction bottoms conversion by coking and gasification

Abstract: Heavy bottoms produced by the liquefaction of coal or similar carbonaceous solids are converted into more valuable products by adding an alkaline earth metal compound to the bottoms in a concentration sufficient to give, following pyrolysis of the bottoms, an alkaline earth metal-to-carbon atomic ratio of from about 0.005:1 to about 0.1:1; pyrolyzing the bottoms at a temperature of from about 900° to about 1600° F. to produce gases, hydrocarbon liquids and coke or char containing added alkaline earth metal constituents; and thereafter gasifying the char with steam.

Composition of gaseous combustion products of polymers

Abstract: The gaseous products generated by the flaming combustion of ten kinds of synthetic polymers and a kind of wood (cedar) under the same conditions (sample weight, 0.1 g; temperature, 700°C air flow rates, 50 and 100 l./hr) were quantitatively analyzed by infrared spectrophotometry, gas chromatography, and colorimetric tube method. The main hydrocarbons generated were methane, ethylene, and acetylene. The amount of acetylene generated by the flaming combustion of polymers was much larger than the amount of acetylene formed by pyrolysis at 700°C in nitrogen. Acetylene increased in quantity with increasing air. For nitrogen compounds, hydrogen cyanide was generated from every polymer containing nitrogen used, but ammonia was detected only for nylon 66 and polyacrylamide. Nitrogen monoxide and nitrogen dioxide were detected only in small amounts. Nitrous oxide was detected in the gaseous products generated by the nonflaming combustion of urea resin and melamin resin. It was also found that about 70% of the nitrogen in N-66 and PAA was converted into nitrogen gas (N2) by combustion under the conditions described above.

Polyolefin catalyst and method for its preparation

Abstract: A new catalyst and a method of polymerizing olefins in which the catalyst is prepared by forming a mixture by dispersing on a finely divided, difficult to reduce, inorganic support of the class consisting of silica, alumina, thoria, zirconia, titania, magnesia and mixtures or composites thereof, an organic chromium compound pyrolytically decomposable in the substantial absence of oxygen to deposit a catalytically active residue along with a carbon residue as a contaminant on the support, then activating the mixture by subjecting the mixture to non-oxidative pyrolysis to and at a temperature within the range of about 600-2000° F., thereby depositing on the support the chromium-bearing residue and carbon residue as a by-product from the pyrolytic decomposition of the organic chromium compound, and subjecting the activated catalyst after this activating to heat and an oxidizing gas such as air, oxygen, carbon dioxide, nitrous oxide, and the like, to burn off a substantial amount of the carbon residue and to modify and improve the characteristics of the activated catalyst.

Carbenic Behaviour of Isocyanoamines generated by Flash Pyrolysis of 4-Arylhydrazono-isoxazol-5-ones. Rearrangement to Cyanamides and Indazoles. Preliminary communication

Abstract: Flash pyrolysis of the 4-arylhydrazono-3-methyl-isoxazol-5-one (1) yields carbon dioxide, acetonitrile, and isocyanoarylamines 2 which under the reaction conditions rearrange to either arylcyanamides 3 or indazoles 4. It is shown by deuterium labelling that only the isocyanoamines not the isomeric nitrile imines are intermediates in the formation of indazoles.