RU2130960C1 - Installation for conducting thermocatalytic hydrocarbon processing - Google Patents

Abstract

FIELD: petroleum processing. SUBSTANCE: invention, in particular, relates to processing hydrocarbon material via dehydrogenation and aromatization on fixed catalyst bed involving periodical regeneration of catalyst such as zeolite-containing one (of the ZSM-5 type). Installation has raw material preheating section, evaporation and heating furnace, a series of furnace-reactor blocks, regeneration gas treatment section, reaction products' separation section, and also pipeline system with control shut-off valves connecting installation sections such as to ensure operating condition for all but one in-series arranged reactors, said one reactor being used to perform regeneration process. EFFECT: reduced number of reactors and valves and improved selectivity of process. 2 cl, 2 dwg, 2 tbl, 2 ex

Description

 The invention relates to oil and gas processing, in particular to the processing of hydrocarbon materials by dehydrogenation and aromatization on a stationary catalyst bed during its periodic regeneration.

 A known installation for reforming light hydrocarbons on a stationary layer of a zeolite-containing catalyst (type ZSM-5), adopted as a prototype ("Z-forming process: conversion of LPG and light naphta to aromatics", 1992, NPRA ANNUAL MEETING, march 22-24, 1992, Marriott / Sheration, New Orleans, Louisiana, Chiyoda Corporation).

 The installation was built according to the traditional scheme, which consists of units for heating raw materials, separating reaction products, preparing catalyst regeneration gas and a furnace block, which consists of several series-connected furnace blocks, each of which in turn consists of a furnace and two parallel reactors, alternately operating and switching to regeneration.

 However, its application has the following disadvantages: a large number of reactors, of which half most of the time is idle due to the fact that the duration of the regeneration mode is approximately an order of magnitude shorter than the duration of the operating mode, and is cooled due to heat loss to the environment; the reforming process is unstable in time due to the gradual coking of the catalyst, which leads to a decrease in the yield and quality of the target products at the end of the working phase before the catalyst regeneration phase; valves that switch the flow of raw materials after the furnace from one reactor to another operate at a high temperature of the raw materials from the heating furnace.

 Also known are platforms for platforming gasoline petroleum fractions, reforming naphtha, propane and butane, dehydrogenating propane and butane with a moving bed and continuous catalyst regeneration (Symposium on conversion of LPG to aromatikas and olefins, UOP / BP cyclar process UOP oleflix process VNIPINEFT, Moscow, feb ., 1992).

 In these installations, the instability of the working process in time and the valve system for switching the reactor units from the operating mode to regeneration and vice versa, and the simple reactors between the regeneration phase and the working phase, are eliminated.

 However, at the same time, they have other drawbacks: a moving catalyst gradually wears out, which requires constant elimination of worn catalyst grains (crumbs) and places increased demands on its strength, which in turn is associated with a decrease in its activity; reactors and regenerators are interconnected by a complex system of pneumatic transport of catalyst grains; catalyst regeneration and screening crumbs require special apparatus; reactors and other devices have complex and expensive equipment.

 All of the above reduces the efficiency and reliability of the prototype and analogues.

 The basis of the invention of the installation, called by us "Zeokat", is the task of creating such an installation scheme in which these disadvantages of the prototype and analogues are either completely or partially eliminated by a fundamentally new scheme for connecting the installation apparatus with pipelines with shut-off equipment (valves), which allows changing the switching sequence reactors in the phases of operation and regeneration, depending on the requirements of the technology and the use of a stationary catalyst bed as the most reliable and not dyavlyayuschego increased requirements for strength of the catalyst and provides simple and inexpensive hardware design, evaporation and separation furnace heating materials to two: the primary heating furnace raw materials to a temperature slightly above the start of the reaction furnace and heating the raw material to a temperature providing endothermal reactions in the reactor.

 All this allows to reduce the number of reactors and valves, as well as increase the selectivity of the reaction.

 The problem is solved in that the installation for carrying out thermocatalytic hydrocarbon processing processes (Zeokat), consisting of a series of n blocks, including a preheater plus reactor, pre-evaporation furnaces, feedstock preheating units, gas preparation for catalyst regeneration, separation of reforming products, as well as a piping system with controlled shut-off valves, it differs in that the raw materials are supplied from a common evaporation and raw materials heating furnace to each unit, and the reformate removal It is located from each block to a common pipeline leading to a feed preheating unit and then to a reformate separation unit, the outlet from each block is connected to the inlet to each of the two next blocks in order, gas for catalyst regeneration is supplied from a common pipeline coming from a gas preparation unit for the regeneration of the catalyst to each unit, the removal of regeneration gases is carried out from each unit to a common pipeline for the discharge of flue gases into the atmosphere or into the regeneration gas preparation unit, each of these pipelines in has a locking device, hermetically sealed and controlled by a command device configured so that the raw materials move sequentially through n-1 blocks that are in operating mode, and one block is in regeneration.

 In addition, in the proposed installation, it may be provided that the outlet from each reactor is connected by a pipeline to controlled shut-off valves with the inlet to the furnace-reactor block located in a series of blocks through one.

The invention is illustrated by drawings, where in FIG. 1 is a diagram of the proposed Zeokat installation for reforming light gasoline, and FIG. 2 - for aromatization of a wide fraction of light hydrocarbons C ₃ , C ₄ .

 The Zeokat installation (see Fig. 1) consists of a unit for heating the raw materials 1, an evaporation and heating furnace to the temperature of the beginning of the reaction of the raw materials 2, a series of n blocks 3, a furnace for heating the raw materials 4, a reactor 5, a gas preparation unit for catalyst regeneration 6 , a unit for separating the products of the reforming reaction 7, collectors for supplying and discharging raw materials 8, collectors for supplying and discharging regeneration gas, and a piping system with shut-off valves 11-15, 21-25, 31-35, 41-45, 51-55.

 The inputs and outputs of the blocks "furnace for heating the raw materials - reactor" 3 are connected by pipelines with shut-off devices (valves) to the collectors for supplying raw materials and removal of reaction products 8 and supply and removal of regeneration gas 9.

 The raw materials from the raw material heating unit 1 are evaporated and heated to a temperature ensuring the start of the reaction in the common furnace 2, and then fed through one of the shut-off valves to the raw material heating furnace 4 and reactor 5, then to the next heating furnace, reactor, etc. through the n-1 refill unit. One of the blocks is disconnected from the raw material and connected to the gas preparation unit for catalyst regeneration 6. As the coking of the catalyst, the last furnace-reactor block in the chain is turned off and put on regeneration, and the block that was previously regenerated is connected to the beginning of the chain.

 Thus, for a full cycle, each of the blocks goes through all stages from the regenerated catalyst to the coked catalyst.

 The number of furnace-reactor blocks is determined by the need for intermediate heating of the feedstock to carry out the endothermic reaction, but should not exceed the ratio of the duration of the processes of operation and regeneration of the catalyst plus one.

 From the above material it follows that the proposed scheme has a number of significant advantages over the traditional scheme in terms of improving the process conditions, reducing the number of reactors, and therefore the amount of catalyst. In addition, shut-off devices in pipelines (for example, valves) are in more gentle conditions, operating at lower temperatures (at the outlet temperature of the endothermic reactor). For example, in the above prototype, at four (n-1) stages of heating the raw material, there are 8 reactors (2 (n-1)), and in the proposed scheme 5 reactors (n).

 The number of valves, slightly smaller, is n = 30 versus 8 (n-1) = 32, in addition, in the proposed scheme, the valves are in milder temperature conditions.

 The proposed installation scheme provides quasi-uniform development of the catalyst in successive reaction steps, which brings the selectivity of the fixed catalyst bed to that of the moving catalyst bed.

 The operation of the installation can be illustrated by examples.

 Example 1. Z - Reforming light gasoline (see Fig. 1, table. 1).

Process conditions:
The temperature in the reactor with a fresh catalyst, ^o C - 410
The temperature in the reactor with a coked catalyst in the phase before regeneration ^o C - 470
Example 2. Z - Reformation of a wide fraction of light hydrocarbons (NGL).

Process conditions - composition of NGL, wt.%: C ₁ - 2; C ₂ - 3; C ₃ - 45; C ₄ - 35; C ₅ - 10; C ₆₊ - 5%.

Since the optimum temperature of Z-reforming of hydrocarbons C ₅ and C _{6 is} in the range 450 - 490 ^o C, and for hydrocarbons C ₃ and C ₄ in the range 540 - 590 ^o C, and the coke formation process on a fresh catalyst, and even at 540 - 590 ^o C during Z-reforming of hydrocarbons C ₅ and C _{6 is} very active, it is advisable to first carry out Z-reforming of C ₅ and C ₆ in a reactor with a high degree of working out at an initial temperature of 490 ^o C, and then direct the flow to a series of reaction steps led with a reactor with a freshly regenerated catalyst for the reforming of C ₃ and C ₄ hydrocarbons at more high temperature.

 To implement this technology, the installation must be additionally equipped with pipelines with valves 16, 26, 36, 46, 56 connecting the exits from the reactors 5 with the entrances to the furnace 4 (see Fig. 2). The operation of the installation is clear from the table. 2.

 The feasibility of the invention is not in doubt, since the proposed installation consists of the same apparatuses as the traditional installation with a fixed bed and periodic operation of the catalyst, only the layout of the apparatus strapping has been changed.

Claims (2)

 1. Installation for carrying out thermocatalytic hydrocarbon processing processes (Zeokat), consisting of a series of n blocks, including a heating furnace and a reactor, a preliminary evaporation furnace, feedstock heating units, gas preparation for catalyst regeneration, separation of reforming products, as well as a piping system with controlled shut-off valves, characterized in that the supply of raw materials is carried out from a common furnace for evaporation and heating of raw materials to each unit, the withdrawal of reformate is carried out from each unit to a common the pipeline leading to the feedstock heating unit and further to the reformate separation unit, the outlet from each block is connected to the entrance to each of the two next blocks in order, gas supply for catalyst regeneration is carried out from a common pipeline coming from the gas preparation unit for catalyst regeneration to each unit, the removal of regeneration gases is carried out from each unit to a common pipeline for discharge of flue gases into the atmosphere, or to the unit for the preparation of regeneration gas, each of these pipelines has a locking device its upmost overlapped and controlled command unit that is configured so that n - 1 blocks are in operation, and one unit is in regeneration.  2. Installation according to claim 1, characterized in that the outlet from each reactor is connected by a pipeline to controlled shut-off valves with an entrance to the furnace-reactor block, which is in a series of blocks through one.

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