RU2174869C1 - Gas-phase catalytic ceiling reactor for thermal-stress chemical processes - Google Patents

Abstract

FIELD: chemical engineering. SUBSTANCE: invention relates to gas-phase reactors for synthesis of hydrocarbon products, spirits and ethers at pressures up to 35/0 MPa and temperatures up to 450 C. Proposed reactor consists of horizontal reaction sections butt-joined with support heat-exchange section. Reaction section is provided with hermetically sealed shelves-baskets with catalyst installed on cantilever crossmembers and insulated from external medium by cooled load-bearing housing installed on rollers. It provides displacement of housing along reaction section axis and free access to any basket or other reaction section members for servicing. Heat-exchange section has gang of modular heat exchangers placed into support stationary load-bearing housing provided with units for attachment of crossmembers and adapters with flanges for butt-joining with load-bearing housings of reaction sections. Inlets-outlets for convertible gas and outlets of communication lines of regulating and control system are made on adapter. After demounting of heat-exchange section, preventive maintenance of modular heat exchangers can be carried out. EFFECT: facilitated servicing of reactor, replacement of catalyst, re-adjustment of reactor for other type of synthesis, high reparability of all components of reactor. 3 cl, 5 dwg

Description

The invention relates to the field of chemical engineering and is proposed to be used in the design of gas-phase, multi-shelf reactors for exothermic or endothermic synthesis of various hydrocarbons, alcohols or ethers from synthesis gas on a fixed catalyst in the pressure and temperature range of the most common synthesis technologies up to 35.0 MPa and up 450 ^o C.

 The field of preferred use of the invention: exothermic synthesis reactors with high volumetric heat release in the catalyst, flow and gas circulation (low and high degrees of gas circulation), industrial plants in a wide range of output power of the target product, mobile complexes for operation in remote gas fields, experimental industrial plants for testing new synthesis technologies.

 A variety of designs of gas-phase catalytic synthesis reactors of low, medium and high power are known. They are most widely represented in methanol and ammonia synthesis technologies. Reviews of typical solutions for gas-phase reactors are given in many books, in particular, in the book by M. M. Karavaev, V. E. Leonov, and I. Popova. and Shepeleva E.T. Synthetic methanol technology. M .: Chemistry, 1984, 240 pp.

 Most industrial reactors are in the form of a vertical packed column with 3 to 6 shelves-baskets to accommodate bulk catalyst. Heat removal is carried out by cold gas, which is mixed with hot reaction gas in the gap between the shelves-baskets (gas quenching, cold bypass). Reactors are also used, the heat removal of which is carried out by means of heat exchangers built in between the shelf baskets. The refrigerant may be a source of cold synthesis gas or an external coolant, such as water. In the latter case, the heat removal system is supplemented by an external steam-water boiler.

 In vertical column reactors, to replace the catalyst, it is necessary to remove all or most of the nozzle combined with heat exchangers from its power casing.

More serviceability is provided by horizontal reactors. This direction is being developed, in particular, by Kellogg (USA). Her European patent N 0256299 dated 02.24.88 for a horizontal quenching reactor for the synthesis of ammonia was taken by us as a prototype
The Kellogg Reactor has a power external cold case cooled by cold convertible gas; removable cold bottom; the inner case in which the functional elements are located - four shelves-baskets with a catalyst and two built-in gas-gas heat exchangers, in which the coolant is the source of cold convertible gas. The inlets and outlets of the source and reaction gas are made in the housing and bottoms.

 The disadvantage of this reactor compared with the proposed one is the lack of access to any functional element without dismantling the adjacent ones, as well as the need to disassemble the pipelines and other communications discharged through the body and bottom. The specified dismantling is necessary, for example, to change the catalyst, prevention, repair or reprofiling of the reactor to the synthesis of another product. The control of the parameters of the convertible gas in such a reactor is achieved only by mixing cold synthesis gas in an appropriate place, which does not allow for regulation in a wide range of parameters, and the direction of movement of the convertible gas cannot be reversed in order to increase the campaign and more fully develop the catalyst.

 The problem to which the invention is directed is to reduce the volume of installation operations when carrying out work with functional elements, to increase the campaign period of the reactor by adjusting the parameters of the convertible gas at any point along its path, as well as the possibility of ensuring gas flow in the opposite direction with minimal readjustment .

 The technical result of the invention is the reduction of installation work by placing the functional elements of the reactor on the fixed part of the reactor, isolated from the external environment by a power casing, the output-input of the convertible gas flows and all communications of the control system through the fixed part, the ability to control the parameters of the convertible gas by adding synthesis gas before any functional element or adjusting the parameters of the convertible gas in the additional heat exchanger, and t Also, reverse flow of convertible gas. The aforementioned task is achieved in that the reactor consists of two parts - a fixed, supporting, stationary structure, including power bodies, adapters, support units for placing functional elements of the reactor and a power body with a flange mounted on the rollers, which allows it to be disconnected from the the adapter of the fixed part to remove the housing, providing access to perform work on any functional element without affecting any other.

 Obtaining the technical result of the invention is possible only by placing functional elements on the fixed part of the reactor, not connected with a movable power casing, which isolates the internal working cavity of the reactor from the atmosphere, the output-input of the convertible gas and the communications of the control system through the fixed part.

 The layout solutions of the inventive reactor, pneumatic circuits and design features of its main parts are presented in FIG. 1, 2, 3, 4, 5.

 In FIG. 1 shows the general layout solution of one of the reactor options.

 In FIG. 2 shows a cross-section of the reaction section AA in FIG. 1.

 In FIG. 3 shows a variant of a pneumatic circuit of a reactor.

 In FIG. 4 shows a variant of a pneumatic circuit of a reactor.

 In FIG. 5 shows a variant of a pneumatic circuit of a reactor.

 In accordance with FIG. 1, the reactor consists of the same type, side, horizontal reaction sections 1 located around the circumference, and one vertical heat exchange section 2.

 The composition of the reaction section includes sealed basket baskets 3 with a bulk catalyst (three baskets are conventionally shown in Fig. 1). The baskets are attached to the cantilever traverses 4. The traverses are box-shaped, the internal cavities of which are used as gas ducts (see Fig. 2).

 Convertible gas is supplied from the traverse gas duct to the baskets and discharged into the traverse gas duct through nozzles 5 having a compensator for temperature expansion. The traverse gas ducts are connected to the gas paths of the heat exchange section using the bypass gas ducts 6 and mounting gas ducts 7.

 The internal cavity of the reaction section is separated from the external environment by a power body 8, which, through linear and angular coordinates, the roller rollers 9 is supported by a foundation. The power housing inside is covered with thermal insulation 10, and the outside is covered with a cover 11, in the gap between them, coolant is pumped through the fittings 12 and 13. The power housing 8 with a cover 11 and thermal insulation 10 does not have rigid ties with the elements inside the housing and can move along the axis of the reaction section.

 For reaction sections of large length, an additional support of the traverse through the rollers 14 on the support rail 15 on the power housing 8 is provided (see Fig. 2).

 The heat exchange section 2 consists of a lower power housing 16 with a support cup 17 forming a bath of boiling water 18 and which is the main supporting element of the reactor. A package of modular heat exchangers 19 is installed in the internal cavity of the power housing, combined into a single unit with a transition ring 20. The number of modular heat exchangers is equal to the number of baskets. With the adapter ring 20, the case of the steam collector 21 is joined, in which there are lattices 22, a collector for supplying feed water 23, a spray trap 24 and a pipe for removing steam 25.

 Tubes 26 with flanges are welded to the outer surface of the power housing 16 for docking with the counter flange of the power housing 8 of the reaction section, power belt 27 with fastening elements traverse 4 of the reaction section. Adapters 28 are installed on the nozzles 26 for supplying convertible gas to the baskets and for removing it from the baskets to the modular heat exchangers 29, as well as the communications leads of the reactor control and monitoring system 30.

 The heat exchange section can operate both in the mode of cooling the convertible gas and stabilizing its temperature, which is regulated by the pressure in the vapor cavity, and in the heating mode by organizing the flow of boiling water using the pipe 31 and when replacing the steam collector 21 with a vapor-liquid collector.

 Sensors of the control and monitoring system are installed on the nozzles 5 and measure the parameters of the convertible gas at the inlet 32 to the basket and at the outlet from it 33, a sensor 34 for measuring the temperature of the catalyst is also provided (see Fig. 2).

 The constituent parts of the reactor — the reaction and heat exchange sections — are made collapsible, and in this layout solution, the maximum autonomy of the dismantling of the elements is realized.

 After undocking the flange connection of the power casing 8 with the adapter 26, the power casing can be freely withdrawn along the axis on the rollers and gain access to any element inside the power casing (see place And Fig. 1). After dismantling the nozzles 5 and measuring communications, any basket can be removed without touching the others. Removable and replaceable are traverses 4 and mounting gas ducts 7.

 The heat-exchange section is also collapsible 2. After dismantling the steam collector housing 21 and the adapter ring 20, it is possible to remove the package of modular heat exchangers 19 and replace any of them.

 The dismantling of the reactor elements is necessary to replace the catalyst, prevent, repair or reprofile the reactor with the release of another product.

 Presented in FIG. 1 as an example, a layout solution with two reaction sections is recommended as the most preferred. For some synthesis technologies, an option with a single reaction section may be optimal.

 In FIG. 3 shows a pneumatic diagram of a reactor with two reaction sections, six baskets 3 with a catalyst and six modular heat exchangers 29. For ease of description, the baskets are given serial numbers K1 ... K6, heat exchangers - T1 ... T6. Convertible gas from the inlet through the pipelines is fed into the first modular heat exchanger T1. From its output, convertible gas with a predetermined and controlled temperature through the gas duct system 7, 6 and 5 enters the upper gas manifold of the first catalyst basket K1. From its outlet gas manifold, reaction gas is supplied through a system of gas ducts 5, 6 and 7 to the inlet of the second modular heat exchanger T2, cooled to a predetermined temperature, and from the outlet T2 through the bypass ducts 7, 6 and 5 it enters the second catalyst basket K2. From its outlet, heated gas through the gas duct system 5, 6 and 7 enters the T3 modular heat exchanger and from its outlet through the gas duct system 5, 6 and 7 into the catalyst basket K3 and further along the path. From the outlet gas collector of the last catalyst basket (in FIG. 3, this is K6), the synthesis products through the outlet are sent to the fractionation system.

The cross sections of the gas path from the inlet to the reactor (point L) to the exit from the reactor (point M) are selected so that the total pressure loss through the gas P _L - P _M does not exceed about 0.3 MPa. The average pressure P = (P _L + P _M ) / 2 or P = (P _L -0.15) MPa is set in the gas cavity of the reaction section (inside the power housing). For this purpose, drainage 35 was made on one of the gas pipes of the middle catalyst basket. The first catalyst basket K1 operates at an internal overpressure of not more than 0.15 MPa, and the latter under an external overpressure of not more than 0.15 MPa. On the nozzles 26 of the heat exchange section, fittings 36 are provided for simultaneously filling and emptying the internal cavities at the start and stop.

 In FIG. 4 shows a pneumatic diagram of a reactor, re-arranged for the reverse flow. Gas is supplied through a modular heat exchanger T6 to the basket K6, is discharged after the basket K1. The circuit also introduced additional heat exchangers 37 and fittings 38 for supplying synthesis gas to dilute the convertible gas and adjust its temperature.

 As you can see, all changes are limited to replacing the gas ducts 7 located on the off-site section with additional heat exchangers and supplying synthesis gas to the fittings on the gas bypass ducts 6.

 In FIG. Figure 5 shows a pneumatic diagram of a reactor, which was reorganized to perform heat removal by cold gas, which is mixed between baskets (gas quenching, cold bypass). After the last basket, the entire gas flow rate is cooled in the integrated heat exchanger.

The claimed design of the reactor differs from the known in the following paragraphs:
(1) according to the general layout scheme combining one or more horizontal reaction sections with one vertical heat exchange;
(2) according to the installation of catalyst baskets on cantilever traverses, the recommended option is two traverses in a section;
(3) according to the pneumatic diagram of the convertible gas path: sealed baskets, gas outlet to the baskets through autonomous gas ducts partially combined with traverse designs, modular heat exchangers autonomous for each basket, automatic equalization of the average pressure in the gas cavity between the pressure at the inlet to the first basket and pressure at the outlet of the last basket;
(4) on the possibilities of carrying out both exothermic and endothermic syntheses;
(5) by the presence of freely dismantled power sections of the reaction sections;
(6) by the availability of freely removable modular heat exchangers and by the design of the heat exchangers themselves;
(7) according to the scheme of dividing the reactor into transportable components;
(8) if possible, change the direction of the gas flow from the first to the last basket to the opposite with the aim of increasing the catalyst campaign due to the reconfiguration of the inlet-outlet of the convertible gas in the out-of-box section, the sequence of passage of the baskets due to the reconfiguration of the internal and external mounting gas ducts; and also, if possible, use a heat removal scheme by mixing cold gas between the baskets; the scheme also allows for any given order of passage of reaction baskets of reaction baskets by installation of automation units on an external out-of-box section;
(9) on the use of various management methods: redistributing the gas flow between the baskets, changing the gas temperature before entering the basket;
and others following from the description and comparison with known constructions.

 These differences provide simplicity of reactor maintenance, first of all, simplicity of catalyst replacement, reactor conversion to another type of synthesis, high maintainability of all its components.

Claims (3)

 1. A gas-phase catalytic shelf reactor for heat-intense chemical processes, including a horizontal reaction section with catalyst shelves-baskets, convertible gas supply and exhaust pipelines, a convertible gas-coolant or cooler heat exchanger section, pipelines for the supply or removal of heat-transfer agent or cooler, power cases, means of control and regulation, characterized in that the catalyst baskets, each of which is sealed and equipped with an individual with a convertible gas inlet-outlet, installed along the length of the reaction section on the power cantilever traverse, the power section of the reaction section is movable to move or remove along the axis of the reaction section, the heat exchange section includes a lower power section forming a bath for a cooler or heater, equipped with a power belt for fastening the cantilever traverse of the reaction section and nozzles with flanges for docking with mating flanges of the power bodies of the reaction sections and placed on the nozzle x nodes for supplying and discharging convertible gas and outputting communications of control and regulation means, an adapter ring in which a package for modular heat exchangers of each basket located in the internal cavity of the power casing with pipelines for supplying and discharging convertible gas and a steam collector with piping for supplying and discharging cooler is installed or heater.  2. The reactor according to claim 1, characterized in that the catalyst baskets have welded shells with flat side walls, reinforced with ribs, removable upper and lower covers, while the supply and removal of convertible gas baskets is carried out through pipelines with heat compensators and through gas ducts in the internal cavities of the traverse, and in the gas duct going to one of the middle baskets of the section along the path of the convertible gas, a drainage is made through which the pressures in this basket are balanced with the pressure in the gas cavity of the power rpusov reaction sections and a decrease in pressure differential across the walls of the other pots.  3. The reactor according to claim 1, characterized in that the nodes of the inlet-outlet of the convertible gas are configured to switch the direction of flow of the convertible gas to the opposite.

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