RU2266778C2 - High-production modular type synthesis gas generator - Google Patents

Abstract

FIELD: organic synthesis; devices of processing of a gaseous hydrocarbon raw.

SUBSTANCE: the invention is pertaining to the field of organic synthesis, in particular, to devices of processing of a gaseous hydrocarbon raw. The high-production module type generator of synthesis gas works according to a method of a high-temperature partial oxidation-combustion of the hydrocarbon gases with the industrial oxygen or air at the nominal pressure of 0.2-10.0 MPa and consumption of the oxygen or the air of 0.2-0.4 as compared to stoichiometry (1.0) with usage of the steam and CO₂ for correction of the synthesis gas composition by a molar ratio of H₂/CO. The basis of the offered design of the synthesis gas generator is a typical module of a combustion chamber with productivity of hydrocarbon gas in terms of methane within the limits of 0.375-3.75 tons per hour. The synthesis gas generator includes from two to several tens modules of the combustion chambers combined in the vertical or horizontal packets with the common cooled body and the common gas withdrawing collecting main. The invention presents the formulas for calculation of the diameter and the length of the active channel, losses of pressure on its inlet and outlet. Usage of the given invention ensures no less than tenfold increase of the volumetric productivity of the synthesis gas generator as compared with its known analog.

EFFECT: the invention ensures no less than tenfold increase of the volumetric productivity of the synthesis gas generator as compared with its known analog.

3 cl, 3 dwg

Description

The invention relates to the field of organic synthesis, and in particular to devices and technology for processing gas hydrocarbon feedstocks into synthesis gas (nH ₂ + СО) by the method of high-temperature partial oxidation of hydrocarbon gases with industrial oxygen or air at pressures of 0.2 ... 10.0 MPa and oxygen consumption of 0.2 ... 0.4 from stoichiometry (1.0).

Known high-temperature reactors (converters) of hydrocarbon gases to produce synthesis gas by the partial oxidation method, widely used in the organic synthesis industry.

One of them, the first analogue, is presented in US patent 4,5882630 dated 04/15/1986 of the French Institute of Petroleum (French patent 8321078 from 12/30/1983).

This patent claims a combined syngas production scheme combining a tube furnace for steam reforming of a portion of natural gas, a parallel combustion chamber of the rest of methane with oxygen deficiency, and a shaft reactor for secondary steam reforming of flows from a tube furnace of a combustion chamber closing circuit. The combustion chamber and the shaft reactor can be performed in one housing, and a direct single-hull tandem circuit is implemented. In this patent, in combination with a very wide range of pressures and temperatures (O ₂ / C molar ratios), in relation to normal conditions (one atmosphere and zero degrees Celsius), the residence times of convertible components in the combustion chamber in the range of 0.001 ... 100 are stated seconds. In terms of these declared residence times for the pressure range of 0.2 ... 10.0 MPa and temperatures of 1000 ... 1800 ° C, the actual residence times in the declared range of approximately 0.00025 ... 2150 seconds. The disadvantage of the analogue is that the upper values of the residence time range are not of practical interest, the lower ones are in no way connected with other parameters of the partial oxidation zone. In the patent materials there are no solutions effective in the range of residence times <0.1 s, when the partial oxidation processes are thermodynamically partially nonequilibrium and the organization of initial mixture formation, which is determined by the design and operation mode of the mixing element - the burner, is of decisive importance.

The closest analogue is a synthesis gas generator (converter), operating by the method of high-temperature partial oxidation - combustion of hydrocarbon gases with industrial oxygen or air at a nominal pressure in the range of 0.2 ... 10 MPa, which includes units for supplying hydrocarbon gas, oxidizer and correction gases, a cooling component, a burner made as a coaxial mixing element, presented in the publication: O.G. Leibush. Process gas production. M., Chemistry, 1971, pp. 276 and 277.

The converter is a perfect mixing reactor, due to the macrocirculation flow pattern in the entire volume, lined from the inside with refractory corundum brick. The cylindrical housing of the converter, for reliable protection against overheating, is equipped with an inner jacket. Chemically purified water or condensate is used to power the shirt. According to the data given on pages 244 ... 247 of the same publication, during the conversion of natural gas, the state of thermodynamic equilibrium is almost completely achieved within ~ 2 s. In practice, taking into account the attached volumes of the units coupled to the converter and limited to achieving quasi-equilibrium, the residence time of the gases in the converter is assumed to be 0.3 ... 0.5 s.

The main disadvantages of the closest analogue are:

- low volumetric performance;

- the presence of the lining requires special care during its installation and its periodic replacement;

- relatively large dimensions and weight.

The objective of the invention is to remedy the above disadvantages.

The problem is solved in the device of a high-performance synthesis gas generator (GHA), operating by the method of high-temperature partial oxidation-combustion of hydrocarbon gases with technical oxygen or air at a nominal pressure in the range of 0.2 ... 10 MPa. The device includes nodes for supplying hydrocarbon gas, oxidizing agent and correction gases, a cooling component. It also includes burners made as coaxial mixing elements for a combustion chamber.

A feature of the proposed solution is that, firstly:

- GHA consists of 2 ... 100 homogeneous modules of combustion chambers arranged in a single assembly with a hydrocarbon gas capacity of each module in terms of methane from 0.375 to 3.75 t / h;

- each combustion chamber module of the same type includes coaxially and sequentially arranged, connected in a detachable or inseparable manner, a burner and a straight-through cylindrical working channel;

- direct-flow cylindrical working channel has a two- or three-walled shell, without lining of the inner wall, with a gap between the walls of 1 ... 5 mm for the passage of the cooling component;

- the inner diameter of the working channel D is selected by the value of the relative flow rate in the range of 10 ^-5 -10 ^-4 s / m, which is defined as the ratio of the total mass flow rate of the gases supplied to the inlet of the working channel to the cross-sectional area of the working channel and to the nominal pressure in the channel ;

- the channel length L is chosen to ensure the residence time of the gases in the range of 0.01 ... 0.1 s;

- at the outlet of the working channel, a cooled or uncooled (made of ceramic) throttle device is installed, made in the form of a nozzle with the possibility of achieving a supercritical pressure drop with subsequent restoration of the subsonic flow in the nozzle diffuser;

- the differential pressure on the throttle device and the burner provide in the range from 0.03 to 0.15 of the nominal pressure in the working channel.

Secondly, the following GHA layout solutions are offered:

- the same type of combustion chamber modules are assembled in a bag with a parallel arrangement of longitudinal modules, for which they are installed in a detachable way in pipes fixed along an annular or hexagonal circuit at the ends of the cooled cylindrical drum housing, longitudinally to the axis of the housing, and it is recommended to choose the number of these pipes from the following row values: 2, 3, 4, 7, 13, 19, 31, 37 and up to 100;

- an odd number of the same type of combustion chamber modules are installed in the bushings along the lateral surface of the cooled cylindrical section perpendicular to the longitudinal axis of its body, and in the general GHA assembly, up to 10 of the same type of sections are used, which are joined together and adjacent assemblies along the common longitudinal axis in a detachable or one-piece way.

Figure 1 shows in section a General view of a typical module of the combustion chamber of the GHA.

Figure 2 shows a schematically high-performance GHA of a modular type in a batch assembly of modules of combustion chambers with their parallel arrangement in a common cooled drum housing.

Figure 3 shows a schematically high-performance GHA of a modular type in the assembly of modules of combustion chambers with their radial arrangement in typical cylindrical cooled sections.

The GHA combustion chamber module includes (see FIG. 1): a gas-gas or a “homogenized (pre-mixed) gas-gas” mixing burner element 1, a direct-flow cylindrical working channel (reaction zone) 2, a throttle a device at the output of the working channel 3, a device for interfacing the module with adjacent GHA elements or units of the production line 4.

As mixing elements-burners 1, it is recommended to use burners, for example, according to patent RU 2168460 from 14.07.99. A feature of the used mixing elements is the organization of the opposite tangential twist of the oxidizer and fuel, while the ratio of the tangential and axial components of the flow rate in each of the oxidizer and fuel flows at their end exit from the channels of the mixing element is recommended to be selected within 0.1 ... 2.0 . In combination with the high longitudinal velocity of both flows, this leads to the formation near the output end of the mixing elements of intense zones of reverse currents - areas of developed macro- and microturbulence. They differ in a relatively small extent along the axis of the reaction zone, but in them an absolutely large part of the reactions of partial oxidation or combustion with a lack of oxygen is completed. Further in the working channel is mainly the alignment of the flow parameters along the cross section. Moreover, to ensure the acoustic stability of the process, the pressure drop along the paths of the oxidizing agent - technically pure oxygen or air, and fuel - convertible hydrocarbon gases, in the mixing element, it is recommended to choose in the range of 0.03 ... 0.15 of the nominal pressure in the working channel. This is ensured by the geometry of the flow sections of the flow paths and their design. You can control the resistance of the tracts after manufacturing using model purges or spills.

The direct-flow cylindrical working channel 2 is a three- or two-wall cylindrical shell with gaps between the walls for the passage of the cooling component. The inner wall, from the inside, is smooth, from the outside it can be smooth, either with wire winding, or with spacers-noodles welded for spacing, or finned. The fins are made in the form of multiple threads, for example a rectangular profile. At pressures in the working channel of less than about 4.0 MPa, and small values of the diameter of the working channel D, approximately less than 75 mm, the inner wall is made without rigid connections with the intermediate or external wall at one of its ends, providing freedom of movement of the second end in the linear direction . To reduce leaks of the cooling component, a sliding seal 5 is used, which is located in the glass 6. Water is predominantly used as a cooler, but at low pressures it is possible to use one of the main components or a correction gas for the composition of the partial oxidation products (Н ₂ O, CO ₂ ). At a pressure of more than 4.0 MPa and a diameter of the working channel of more than 75 mm, it is recommended that the double-walled cylindrical shell of the body of the working channel be used by brazing along ribs or corrugations.

The throttle device 3 at the outlet of the working channel is made in the form of a cooled nozzle or nozzle array providing supercritical pressure difference, but with the restoration of subsonic flow in the nozzle diffuser. To organize the flow of cooler along the corresponding surface of the throttle device 3, a displacer 7 is used, made, for example, of two or more parts fastened by a glass 6. It is possible to use uncooled throttle devices made of ceramic materials. The choice of the type of throttle device, cooled or uncooled, depends on the availability of materials that are workable in a particular GHA, the ratio of their price and quality. In this case, the pressure drop across the gas on the throttle element in all cases is selected in the range of 0.03 ... 0.15 of the nominal pressure in the working channel. Provide this differential structurally due to the geometry of the nozzle (diffuser angle).

Figure 2 schematically shows the GHA, in which the modules of the combustion chambers 8 are detachably mounted in pipes 9 fixed to the ends of the cooled cylindrical drum housing 10 in an annular or hexagonal circuit, with the number of modules of the combustion chamber in the assembly 2, 3, 4, 7 , 13, 19, 31, 37 and up to 100. The longitudinal axis of the modules 8 are parallel to the longitudinal axis of the housing 10. The GHA also includes an output gas collector 11, covering the gas outlets of all modules 8, start-off valves and flow controllers (stabilizers) for all component feed lines tov 12, incendiary device 13, manifolds 14 for wiring components into the GHA combustion chamber modules.

The collector 11 can be performed without inner lining, double-walled, brazed along the ribs or corrugations, cooled by water. With the help of the collector 11, a modular GHA is docked with the units of the production line adjacent to the gas path, for example, with a heat recovery boiler (KUT), with a high-temperature soot cleaning nozzle filter (gasification of deposited soot by steam) or with a two-stage GHA type closing catalytic stage, which modular GHA performs the functions of the first stage.

To ignite the combustible mixture in the working channels at the time of launching the GHA, an incendiary device 13, for example, an electroplasma type (EPZU), running on a standard oxidizer - oxygen or air, and a convertible gas, mounted on the spacer-boss of the collector 11. is used. self-ignition of the combustible mixture is ensured in the flame front stabilized by the end edge of the separation wall of the oxidizer and fuel flows in the mixing element.

The main functions of the incendiary device of the incandescent type in the main modes are also performed by the elements of the end bottom of the housing 10 or module 8 heated to a temperature of more than 600 ° C.

Figure 3 shows schematically the GHA, in which the modules of the combustion chambers 8 are mounted radially and evenly around the circumference in the bushings 15 on the side surface of a typical section of the GHA 16 having a cooled case. The longitudinal axis of the modules is perpendicular to the longitudinal axis of the housing of the section 16. It is recommended that the number of modules be chosen odd to reduce the penetration of the high-temperature gas stream from one module to another. On the one side, a cooled cover 17 is joined to the section, and on the other hand, a similar GHA section or gas outlet manifold 18, the design and purpose of which is the same as that of the collector 11 (see Fig. 2). An EEPROM 13 is installed on the cover 17, it can also be installed on the housing of the section 16, on the collector 18, or on each module 8 in a spacer between the mixing element and the working channel (see Fig. 1).

The main dimensions of the working channel, diameter D and length L, are determined by the selected flow rate and the residence time of gases in the working channel. The formula for calculating the relative flow rate q (see GOST 17655-72. Liquid rocket engines. Terms and definitions) is as follows:

where: m _Σ is the total mass flow rate of the gases supplied to the entrance to the working channel, kg / s;

F _k - the cross-sectional area of the working channel, m ² ;

P _k - nominal gas pressure in the working channel, N / m ² .

Taking into account the experience of analogue aggregates in related industries (see V.E. Alemasov et al. Theory of rocket engines. M: Mashinostroenie, 1989; A.P. Vasiliev et al. Fundamentals of the theory and calculation of liquid rocket engines. M. : Higher school, 1967) it is proposed q to choose between 10 ^-5 ... 10 ^-4 s / m, and the residence time from 0.01 to 0.1 s.

GHA works as follows. In the combustion chamber module, see Fig. 1, gaseous oxidizing and combustible components come from the mixing element 1 into the working channel 2, where the mixture ignites at the start, while the channel 2 is still at a low speed, the ignition is carried out due to the flame of the EEPR upstream to the mixing element. Further ignition occurs spontaneously in the flame front of the mixing element. Ignition insurance is provided by glow elements at the end of the GHA housing or throttle device. Partial oxidation products formed in the combustion chamber module expire, see FIGS. 2 and 3, into the outlet gas manifold 11 or 18. The cooling schemes of all GHA elements are clear from the drawings shown in FIGS. 1, 2 and 3.

This invention provides the creation of GHA with a volumetric capacity of not less than 10 times higher than that of the closest analogue. At the same time, it is recommended to choose the productivity of each module of the combustion chamber for hydrocarbon gas in terms of methane in the range from 0.375 to 3.75 t / h, and the levels of 0.5 ... 1.0 million tons can be achieved in absolute productivity in one unit in year.

The present invention proposed a design that implements a nonequilibrium process organization scheme combining perfect mixing of the flows of combustible and oxidizing components in the reverse current zone, near the output end of the mixing element-burner, due to the formation of macro- and microvortices in this zone by the design and operation of the burner, followed by ideal displacement due to the organization of forward flow in the working channel of the camera.

Claims (3)

1. The device is a high-performance synthesis gas generator operating by the method of high-temperature partial oxidation-combustion of hydrocarbon gases with industrial oxygen or air at a nominal pressure in the range of 0.2-10.0 MPa, including nodes for supplying hydrocarbon gas, oxidizer and correction gases, cooling component, burners made according to the type of coaxial mixing elements for a combustion chamber, characterized in that it includes 2 to 100 identical modules of combustion chamber modules arranged in a single assembly wound with a productivity of each module for hydrocarbon gas in terms of methane from 0.375 to 3.75 t / h and each chamber module of the same type includes a burner coaxially and sequentially connected and connected in a detachable or inseparable manner and a straight-through cylindrical working channel having two or a three-walled shell, without lining the inner wall, with a gap of 1-5 mm for the passage of the cooling component, while the inner diameter D of the working channel is selected by the value of the relative flow rate q in the range of 10 ^-5 -10 ^-4 s / m, which is defined as the ratio of the total mass flow rate of the gases supplied to the inlet of the working channel to the channel cross-sectional area and to the nominal pressure in the channel, and the channel length L is selected with a gas residence time in the channel of 0, 01-0.1 s, and a cooled or uncooled throttle device made in the form of a nozzle is installed at the outlet of the working channel, with the possibility of achieving a supercritical pressure drop with subsequent restoration of the subsonic flow in the diffuser with pla and providing a differential pressure on the throttle device and burner from 0.03 to 0.15 of the nominal pressure in the working channel. 2. The device according to claim 1, characterized in that the same type of modules of the combustion chambers are assembled in a bag with a parallel arrangement of the longitudinal axes of the modules, for which they are installed in a detachable way in pipes fixed in parallel along an annular or hexagonal circuit at the ends of the cooled cylindrical body - drum longitudinally the axis of the housing, and the number of these pipes is recommended to be selected from a number of values 2, 3, 4, 7, 13, 19, 31, 37 and up to 100. 3. The device according to claim 1, characterized in that a predominantly odd number of the same type of combustion chamber modules is installed in the bushings along the lateral surface of the cooled cylindrical section perpendicular to the longitudinal axis of its housing, and up to 10 sections of the same type are used in the general assembly of the synthesis gas generator, which join together and adjacent assemblies of the synthesis gas generator along a common longitudinal axis in a detachable or one-piece way.

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