FI68074C - FOER FARANDE OCH ANORDNING FOR THERMAL BEHANDLING AV KOLVAETEHALTIGA MATERIAL - Google Patents

Description

68074

Method and apparatus for the thermal treatment of hydrocarbonaceous materials Förfarande och anordning för termisk behandling av kolvätehaltiga material

The invention relates to a process for treating materials containing carbon or hydrocarbons by thermally decomposing the hydrocarbon material into gaseous and vaporous hydrocarbons and solid waste, the oxidation of which produces the thermal energy required by the decomposition reactions.

The invention also relates to an apparatus for treating materials containing carbon or hydrocarbons by thermally decomposing the hydrocarbon material into gaseous and vaporous hydrocarbons and solid waste, the oxidation of which produces the thermal energy required for the decomposition reactions.

15 The method is suitable for the treatment of materials containing carbon or hydrocarbons as well as various biomasses and for the further distillation of heavy oil residues from oil refineries in order to increase the yield of light petroleum products such as petrol and diesel.

20 When heavy hydrocarbons are heated in an oxygen-free state, they decompose into different, lighter hydrocarbons and solid residues, depending on the chemical nature and the speed of the heating process. Utilizing this phenomenon, the energy required for decomposition is generated by oxidizing the carbonaceous solid residue. Most commonly, thermal energy from the oxidation reactor to the decomposition reactor is transferred by circulating solid material between the reactors. Technically, the process is implemented by connecting two fluidized bed reactors in parallel, the fluidized material of which is recycled from one reactor to another. Methods and apparatus are also known in which the thermal energy of an oxidation reactor is transferred using an indirect heat exchanger of thermally decomposable material 30.

2 68074

As circulating fluidized bed reactors 1, circulating fluid bed reactors are used, the recirculation of which takes place from one reactor to another. The disadvantages of this solution (EP 00 12468) are the complicated and expensive equipment and the difficult-to-control, labile process. It is particularly problematic to control the distribution of circulating material between the oxidation and decomposition reactors. One important control parameter of the thermal decomposition process is the delay time. In twin-reactor solutions, the delay time is mainly capacity-dependent and its control possibilities are limited. In addition, a significant disadvantage is the need for a fluidizing gas in the decomposition reactor 10, in which a cooled product product, usually containing condensed hydrocarbons, must be used for fluidizing and transporting solids. The need for fluidizing gas in the decomposition reactor also increases operating costs. For these reasons, twin-reactor solutions have not been commercially competitive or technically sufficiently reliable.

Solutions based on indirect heat transfer are technically problematic. The main difficulties are e.g. fouling of thermal surfaces and blockage of ductwork, transport of solid material in the decomposition reactor-20, heat transfer as a solid material, corrosion and erosion problems of the material, and design issues. Indeed, a method based on indirect heat transfer is practically impossible.

The process according to the invention is mainly characterized in that, after thermal decomposition, the circulating material is separated from the hydrocarbon products and returned to the oxidation reactor, liquid hydrocarbons are separated from the hydrocarbon products by condensation and gaseous hydrocarbons are partially or completely returned to the decomposition reactor.

Other features of the method according to the invention are set out in claims 2-4.

The device according to the invention, in turn, is mainly characterized in that the device consists of a circulating mass reactor comprising an oxidation reactor and a return pipe adapted to act as a decomposition reactor to decompose the hydrocarbon material fed to it, and that the return pipe is

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3 68074 for separating the resulting gaseous and vaporous hydrocarbons from the circulating material which returns to the oxidation reactor through the lower part of the return pipe.

Other features of the device according to the invention are set out in claims 6-11.

In the process according to the invention, the starting point is a circulating mass reactor, in the oxidation reactor of which the temperature is adjusted to the desired level by controlling the introduction of oxygen. In the oxidation reactor, the circulating mass is raised to a heat separator, where the gases and the circulating mass are separated from each other. Oxidation reactor exhaust gases generally contain combustible gases and can be utilized either as a synthesis gas or in an energy production mode.

The process according to the invention differs from the known processes most substantially in that the thermal decomposition reaction is obtained by feeding the material to be decomposed to a decomposition reactor operating as part of a circulating mass recovery pipe. Immediately after the decomposition reactor, the circulating pulp and hydrocarbon gases are also passed to a second heat separator as part of the return pipe, from which the solid residue and circulating pulp are returned to the oxidation reactor and the hydrocarbon gases are removed for further processing.

The presented method can solve the above-mentioned disadvantages of a twin reactor. Technically, a simple and inexpensive reactor is obtained, the flow control of which is not substantially more difficult than that of a conventional circulating mass reactor. A separate gas flow is not required to transport the circulating mass and the delay time in the decomposition reactor can be adjusted by changing the feed point of the material to be decomposed.

The invention will be explained in detail with reference to the principle solution of the invention shown in the figure of the accompanying drawing, to which the invention is not intended to be exclusively limited.

Unit 1 shows a supply point for thermally decomposable material, the vertical position of which can be adjusted. The decomposition reactor operating as part of the recovery pipe 11 is denoted by the reference number 2. The lower end of the decomposition reactor 2 is connected to a heat separator 3, from which the solid residue and the circulating mass are fed to the oxidation reactor 8 via the pipe 5. The distilled light hydrocarbons are removed from the separator up to pipe 4.

Oxygen flow is passed to the oxidation reactor 8 from the cabinet 6 through the distribution plate 7.

In reactor 8, the ratio of oxygen to solid residue is generally adjusted in the substoichiometric range so that the temperature is set to the desired value. From the oxidation reactor 8, the gases and the circulating mass are passed through a duct 9 to a hot separator 10, from where the circulating material is passed through a downcomer 11 to a decomposition reactor 2. The oxidation reactor gases leave the separator 10 10 via a pipe 12.

The hot separators 3 and 10 are known separators, most usually centrifugal separators or cyclones. It is preferable to place the lower end of the return pipe 5 of the heat separator 3 in the vicinity of the air distribution plate 7, whereby the gas flow 15 from the oxidation reactor 8 to the decomposition reactor 2 is limited due to the stabilizing effect of the fluidized bed. In the connecting pipe 11 of the upper heat separator 10 and the decomposition reactor 2, the gas flow is limited by dimensioning the cross-sectional area of the pipe 11 small compared to the cross-sectional area of the decomposition reactor 2.

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In the decomposition reactor 2, the temperature, pressure and delay time are selected so as to maximize the proportion of the desired gaseous and vaporous hydrocarbons. The gases and vapors, which can be further purified before cooling, if necessary, are passed through a pipe 4 to a condenser 13, where the vaporous hydrocarbons condense into liquids. The separator device 14 separates the liquid components, which are removed together via 16. The gaseous compounds contain hydrogen and methane (CH 2), which are recycled via line 15 back to the decomposition reactor 2. As a result of the recirculation, the hydrogen / carbon ratio of the decomposition reactor 2 is increased and at the same time the yield of the desired hydrocarbons is increased. The yield of the desired hydrocarbons can also be increased by introducing an external hydrocarbon stream 17 (most typically methane) into the decomposition reactor 2.

The gas flow rate in the oxidation reactor 8 is thus selected to be 3 to 10 m / s so that sufficient transport of the circulating material to the heat separator 10 is achieved. It is known that the circulating mass flow can also be influenced by the amount and quality of the reactor circulating mass (density, particle size), so that the thermal power of the decomposition reactor 2 can be easily adjusted by the method according to the invention.

If an economically viable use is found for the product gas of the oxidation reactor 8, its flow can be regulated by a separate hydrocarbon feed 19. In this case, the oxidation reactor 8 operates like a conventional circulating mass gasifier which produces low or medium calorific value gas. In special cases, the oxidation reactor 8 may also include cooling surfaces 18.

It is clear that the method and apparatus according to the invention can also be used for the thermal decomposition of inorganic compounds.

Claims (11)

1. A process for treating materials which contain carbon or hydrocarbons in such a way that the hydrocarbon material is thermally decomposed into gaseous and meadow hydrocarbons and a solid residue, with the oxidation producing the thermal energy required for the decomposition reaction, and the thermal decomposition of the hydrocarbon material. in a decomposition reactor (2) forming part of the circulation mass reactor circulation material (11) which acts as an oxidation reactor (8), characterized in that, after the thermal decomposition, the circulation material is separated from the hydrocarbon products and returned to the oxidation reactor (8). ), from the hydrocarbon products, the liquid hydrocarbons are separated by condensation and the gaseous hydrocarbons are partially or completely returned to the decomposition reactor (2). 2. A process according to claim 1, characterized in that in order to increase the recovery of the hydrocarbons from hydrogen containing gas from outside the decomposition reactor (2). 3. A process according to claim 1 or 2, characterized in that the decomposition reaction of the hydrocarbons is controlled by changing the degree of condensation of the hydrocarbons which are removed from the decomposition reactor (2) and in this way the deposition of the gaseous hydrocarbons which is returned to the decomposition reactor. Method according to claim 1, 2 or 3, characterized in that the delay time in the decomposition reactor (2) is regulated by changing the pI feed point (1) in the high direction. 5. Device for treating koi or hydrocarbons containing matter! in such a way that the hydrocarbon material is thermally decomposed into gaseous and gaseous hydrocarbons and to a solid residue, the oxidation of which produces the thermal energy required for the decomposition reaction, it can be characterized that the device is formed by a circulation mass reactor ( 8), and a return pipe (11) wherein a portion of the return pipe (11) is adapted to act as a decomposition reactor (2) for decomposing the hydrocarbon material measured therein,