Title of Invention

"AN INTERNAL EQUIPMENT FOR A VERTICAL CHEMICAL REACTOR"

Abstract An internal equipment of a vertical chemical reactor containing horizontal perforated plates and phase contact tubular devices, each phase contact tubular device includes downward vertical tube and upward vertical tube, the phase contact tubular device being attached to a filling support by its upper end, the downward vertical tube is plugged from the upper gas end and has a gas inlet and a liquid inlet at the top of its side face, the upward vertical tube has a gas-liquid mixture outlet on the internal equipment support, Wherein said downward vertical tube and upward vertical tube of each phase contact tubular device are tubes of circular cross-section, the axes of said tubes of each phase contact tubular device are parallel with each other and distant from each other of two or more times diameters of the tube, said downward vertical tube and upward vertical tube of the same phase contact tubular device are joined together in their lower part with U-shaped element from the tube of the same diameter as said downward vertical tube and upward vertical tube.
Full Text Field of the Invention
The invention relates to internal devices of chemical reactors for carrying out processes in gas-liquid media and may be used, for example, for synthesising carbamide (urea) from ammonia and carbon dioxide at high temperatures under elevated pressure.
Background of the Invention
There are known whole reactors for carrying out processes in gas-liquid medium, specifically, for urea synthesis, which reactors are vertical high pressure vessels, provided with internal corrosion-resistant lining and piping for inlet and outlet of reactants (V.I.Kucheryavy, V.V. Lebedev. Carbamide Synthesis and Use, Moscow, Chemistry Edition, 1970, p. 316-317).
A disadvantage of such reactors is their low performance. A considerable portion of make-up reactants of urea synthesis reactor, like reactors for some other processes, presents in the inlet zone as gas phase. The gases transfer into liquid phase as the process goes on. Reactants conversion of these processes in the hollow reactor is not sufficient because of low efficiency of gas-liquid mixing.
As it is known from operation experience, satisfactory conversion rate of carbon dioxide to urea X being about 65% may be reached in the hollow reactor only at low specific capacity II, about 300-400 kg urea/m3.hr. The more make-up reactants feeding rate, the less X, lowering down to 57-58% when II raising up to 650-700 kg urea/m3 .hr. Increase of recycle caused by lowering X results in impermissible worsening technical-and-economic indices.
There are known sets of internal equipment of vertical reactors for carrying out processes in gas-liquid medium, specifically, for urea synthesis. Each of the known sets includes horizontal perforated plates, ensuring increased efficiency of gas-liquid mixing within each zone between neighbouring plates and some extent of bringing general flow structure in the reactor to plug-flow operation (USSR Inventor's Certificates 808, 122, B 01 J 19/00, 1981; 1,088,779, B 01 J 10/00, 1984). Inadequate distribution of gaseous phase through cross-section of the reactor causes insufficient performance of the synthesis process and comparatively low specific capacity of the reactor provided with said internal equipment.
The nearest to the internal equipment of the invention in respect of its technical essence is the known internal equipment of a vertical reactor containing horizontal perforated plates and contact devices, each device includes two vertical tubular members, lowering one and lifting one, the members being attached to a supporting sheet by their top ends, the lowering member being plugged from the upper end and has openings for a gas and a liquid inlet at the top of its side surface, the lifting member having an opening on the supporting sheet for a gas-liquid mixture outlet, each contact device being a tube divided to a lowering member and a lifting

member by an internal vertical partition, an upper end of the partition being closely adjacent to the supporting sheet, and a lower end of the partition does not reach plugged bottom of the tube (Russian Patent 2,114,691, B 01 J 10/00, 1998).
Said known internal equipment is aimed to bring macroscopic structure of the flow in the reactor, as a whole, closer to plug-flow operation, specifically, in the lower part of the reactor, and increase specific capacity of the reactor. The vertical contact devices with the lowering and the lifting member provide excluding longitudinal and cross-sectional agitation of the reaction medium in the area of placing the devices. Moreover, gaseous phase is distributed through cross-section of the lower part of the reactor more uniformly, due to the formation of a gas cushion under the supporting sheet, i.e., in the zone of inlet of the reactants into the contact devices.
Disadvantages of said known internal equipment are its manufacturing and assembly difficulties as well as design complexity, the assembly including the manufacture of long, narrow plates with the width, equal to the internal diameter of the tube, followed by its inserting into the tube, or bending and longitudinal welding S-shaped blanks. Moreover, the contact device has a considerable pressure drop. Distributing gas and liquid through cross-section of the lowering member is not enough uniform, because phases are introduced into the device along semicircle but not perimeter of the lowering member.
Summary of the Invention
To increase adaptability of an internal equipment for efficient gas-liquid reactors to its manufacture, an internal equipment of a vertical reactor is proposed, which equipment contains horizontal perforated plates and contact devices, each device includes two vertical tubular members, lowering one and lifting one, and is attached to a supporting sheet by its upper end, the lowering member is plugged from the upper end and has opening┬žibr a gas and a liquid inlet at the top of its side surface, the lifting member has an opening on the supporting sheet for a gas-liquid mixture outlet, the equipment is characterised in that said vertical tubular members of each contact device are manufactured from tubes, the axes of the members of each contact device are parallel and placed from each other of two or more diameters of the tube distant, the members of the same contact device are joined together in their lower part with U-shaped member manufactured from the tube of the same diameter as said vertical members.
The proposed invention, owing to use of tube of the same size, results in simplifying the manufacture and assembly of the contact devices and the equipment as a whole and decreasing pressure drop in the device during operation. Additional U-shaped contact member increases reactor performance due to intensification of phase contact in the field of centrifugal forces. Round cross-section of the lowering member ensures arrangement of the inlet openings for gas and liquid on the member perimeter to be uniform, providing corresponding distribution of the
phases inside the member. A distance between the axes of the lowering member and lifting member being more than two, preferably, from two to six tube diameters, ensures moderate pressure drop of the contact device. Distance below two tube diameters increases pressure drop and decreases reactor efficiency. Distance above six tube diameters makes arrangement of the contact devices in the supporting sheet to be insufficiently compact.
It is preferred, a ratio of the height of the contact device to the diameter of the tube for its manufacturing to be within the limits from 40 to 150. When the ratio is below 40, hydrodynamic conditions of the reactor are insufficiently stable. When the ratio is above 150, pressure drop of the contact device is increased materially, and, at the same time, its rigidity is decreased, causing additional supporting elements to be required which make the design of the equipment more complicated.
It is preferred also, to make the lowering member plugged from above with a plug, its lower end face being placed below than lower surface of the supporting sheet. Owing to this, fastening of the lowering member is more rigid than the same of the lifting member. Therefore, natural frequencies of the members are different, and resonance frequency is detuned preventing a possibility of dangerous vibration of the contact devices.
Brief Description of the Drawing Figures
The proposed invention is illustrated with the drawings of the Fig. 1 and 2. Fig. 1 represents a longitudinal cross-section of the vertical reactor with the internal equipment inside. Fig. 2 represents a contact device attached to the supporting sheet (unit A of Fig. 1).
Description of the Preferred Embodiment
According to the Fig. 1 and 2, reactor includes a vertical shell 1 with a flange cover 2, piping 3, 4, 5 for inlet of the reactants, piping 6 for product outlet. Internal equipment includes horizontal perforated plates 7, 8, dividing the reaction volume of the reactor into several zones (a number of the plates can be more than two), and contact devices 9, the devices being manufactured from tubes of a constant cross-section and arranged in a lower third of the reactor where a share of gas phase is essential.
Each contact device 9 includes two vertical members, the lowering member 10 and the lifting member 11. The members 10 and 11 are connected in their lower parts with the additional U-shaped member 12. Upper parts of the members 10 and 11 are fixed in the supporting sheet 13, a distance between the parallel longitudinal axes of these members being more than two tube diameters, preferably, of two to six tube diameters. Openings 14 and 15 for inlet of gas and liquid, correspondingly, are arranged uniformly along the circumferences on the side surface of the lowering member 10, below the supporting sheet 13. The openings 14 are placed above than the openings 15. Upper end of the lowering member 10 has the plug 16 insetted into the member.
Lower end face of the plug 16 is below than lower surface of the supporting sheet 13. Outlet opening 17 of the lifting member 11 is placed on the upper surface of the supporting sheet 13.
The supporting sheet 13 includes a short shell 18, its height spreading over openings 14 and 15.
The additional U-shaped member 12 may be manufactured apart from the members 10 and 11 followed by welding them together with two circumferential welds. Alternatively, the member 12 may be manufactured together with the members 10 and 11 from the same tube.
The reactor provided with the proposed internal equipment operates as follows. Liquid and gaseous reactants, for example, ammonia, carbon dioxide and ammonium carbamate solution in the case of urea synthesis, are fed to the reactor through piping 3, 4, 5. The reactants are mixed and distributed through cross-section of the reactor with the aid of the plate 8. After passing this plate, gas-liquid mixture comes into a zone filled with vertical contact devices 9. Overtaking the liquid in the upward current, gaseous phase forms a gas cushion below supporting sheet 13. Gas and liquid enters separately into the lowering member 10 through the openings 14 and 15, correspondingly, which openings are uniformly arranged along the circumferential perimeter of the lowering member 10. Then, the phases enters in the contact within the member 10 in the downward cocurrent flow.
Gas-liquid contact is continued within U-shaped member 12 more intensively due to centrifugal forces. Gas-liquid flow passes upwardly the lifting member 11 and comes through opening 17 into next reaction zone of the reactor. After passing top plate 7, reaction products leave the reactor through the piping 6.
Gas phase is distributed uniformly through reactor cross-section and among contact devices due to the gas cushion under the supporting sheet 13 with phase interface placed between openings 14 and 15.
Industrial Usability
The prototype of the proposed internal equipment has been manufactured and tested in an urea synthesis reactor. The tests have been showed that specific quantity of metal is not more, specific capacity II and conversion rate X not less for the prototype than for the known internal equipment providing the same residence time of the reactants and, correspondingly, the same process performance. At the same time, working hours for manufacturing the contact devices and assembly of the internal equipment is 20-25% less.





We Claim:
1. An internal equipment of a vertical chemical reactor containing horizontal
perforated plates and phase contact tubular devices, each phase contact
tubular device includes downward vertical tube and upward vertical
tube, the phase contact tubular device being attached to a filling support
by its upper end, the downward vertical tube is plugged from the upper
gas end and has a gas inlet and a liquid inlet at the top of its side face, the
upward vertical tube has a gas-liquid mixture outlet on the internal
equipment support, the internal equipment is
characterized in that said downward vertical tube and upward vertical tube of each phase contact tubular device are tubes of circular cross-section, the axes of said tubes of each phase contact tubular device are parallel with each other and distant from each other of two or more times diameters of the tube, said downward vertical tube and upward vertical tube of the same phase contact tubular device are joined together in their lower part with U-shaped element from the tube of the same diameter as said downward vertical tube and upward vertical tube.
2. An internal equipment of a vertical chemical reactor as claimed in the claim 1 the said axes of downward vertical tube and upward vertical tube of each phase contact tubular device are distant from each other of two to six times diameters of the tube.
3. An internal equipment of a vertical chemical reactor as claimed in the claim 1, 2 the ratio of the height of the phase contact tubular device to the diameter of the tube for its manufacturing is within the limits from 40 to 150.
4. An internal equipment of a vertical chemical reactor as claimed in the claim 1, 2, 3 the said downward vertical tube is plugged from above with a plug fitting, its lower end face being placed below than lower face of the filling support.
5. An internal equipment of a vertical chemical reactor containing horizontal perforated plates and contact devices substantially as herein described with reference to the foregoing description and the accompanying
drawings.

Documents:

in-pct-2002-00668-del-abstract.pdf

in-pct-2002-00668-del-assignment.pdf

in-pct-2002-00668-del-claims.pdf

in-pct-2002-00668-del-complete specification [granted].pdf

in-pct-2002-00668-del-correspondence-others.pdf

in-pct-2002-00668-del-correspondence-po.pdf

in-pct-2002-00668-del-description (complete).pdf

in-pct-2002-00668-del-drawings.pdf

in-pct-2002-00668-del-form-1.pdf

in-pct-2002-00668-del-form-18.pdf

in-pct-2002-00668-del-form-2.pdf

in-pct-2002-00668-del-form-3.pdf

in-pct-2002-00668-del-form-5.pdf

in-pct-2002-00668-del-gpa.pdf

in-pct-2002-00668-del-pct-210.pdf

in-pct-2002-00668-del-pct-304.pdf

in-pct-2002-00668-del-pct-331.pdf

in-pct-2002-00668-del-pct-409.pdf


Patent Number 239597
Indian Patent Application Number IN/PCT/2002/00668/DEL
PG Journal Number 14/2010
Publication Date 02-Apr-2010
Grant Date 25-Mar-2010
Date of Filing 04-Jul-2002
Name of Patentee OTKRYTOE AKTSIONERNOE OBSCHESTVO "NAUCHNO-ISSLEDOVATELSKY I PROEKTNY INSTITUT KARBAMIDA I PRODUCTOV ORGANICHESKOGO SINTEZA" (OAO NIIK)
Applicant Address UL. GRIBOEDOVA, 31 DZERZHINSK, NIZHEGORODSKAYA OBL., 606008, RUSSIA
Inventors:
# Inventor's Name Inventor's Address
1 ZHESTKOV, SERGEI VASILIEVICH BULVAR POBEDY, 5-28, DZERZHINSK, NIZHEGORODSKAYA OBL. 606000 RUSSIA
2 SERGEEV , JURY ANDREEVICH UL PETRISCHEVA, 18/39-229, DZERZHINSK, NIZHEGORODSKAYA, OBL.,606037, RUSSIA
3 POTAPOV, VIKTOR VALERIYANOVICH PR. TSIOLKOVSKOGO, 8-27, DZERZHINSK, NIZHEGORODSKAYA OBL., 606000, RUSSIA
4 KUZNETSOV, NIKOLAI MIKHAILOVICH BULVAR POBEDY, 3-20, DZERZHINSK, NIZHEGORODSKAYA OBL.,606000, RUSSIA
5 NAZAROV, NIKOLAI PAVLOVICH PR. TSIOLKOVSKOGO, 54-44, DZERZHINSK, NIZHEGORODSKAYA OBL., 606029, RUSSIA
6 GUSEV, ANATOLY IVANOVICH BULVAR POBEDY, 3-18,DZERZHINSK NIZHEGORODSKAYA OBL., 606000, RUSSIA
7 PROKOPIYAV, ALEXANDR ALEXEEVICH UL. OKTYABRSKAYA, 6-69,DZERZHINSK, NIZHEGORODSKAYA OBL., 606008, RUSSIA
8 ESIN, IGOR VENIAMOVICH PR. TSIOLKOVSKOGO, 4-14, DZERZHINSK, NIZHEGORODSKAYA OBL., 606000, RUSSIA
9 SONIN, IGOR NIKOLAEVICH PR. TSIOLKOVSKOGO, 65-49, DZERZHINSK, NIZHEGORODSKAYA OBL., 606029, RUSSIA
10 KOSYREV, MIKAHAILOVICH PR. TSIOLKOVSKOGO, 57A-12, DZERZHINSK, NIZHEGORODSKAYA OBL., 606029, RUSSIA
11 BESPALOV, ANATOLY DIAMIDOVICH UL. POPOVA, 8A-38,DZERZHINSK, NIZHEGORODSKAYA OBL., 606030, RUSSIA
PCT International Classification Number B01J 10/00
PCT International Application Number PCT/RU01/00097
PCT International Filing date 2001-03-05
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 2000108232 2000-04-03 Russia