CN2515637Y - External heat-transfer apparatus - Google Patents

Abstract

The utility model relates to an external heat collector used in a catalytic cracking unit in the petrochemical plant, comprising nail-head heat transferring tubes and a shell. The nail-head heat transferring tubes are arranged inside the cylindrical shell. Each nail-head heat transferring tube is of sealed structure, and is composed of a water supply pipe and a steam sleeve with a nail head, which forms a heat transferring element with an independent water vapor loop. One end of each nail-head heat transferring tube is fixed on a sealing head, and the other end is positioned inside the shell so that the nail-head heat transferring tube can be extended freely. An inlet tube and an outlet tube of catalyst and an inlet pipe of a fluidization air distributor are arranged on the shell, and the fluidization air is discharged from an air returning port. The novel external heat collector not only has high heat transferring efficiency but also has good wear resistance and reliability.

Description

A kind of external warmer

The utility model belongs to the process equipment of petrochemical plant catalytic cracking unit, more particularly, is the improvement to the external warmer that is used for catalytic cracking unit.

Be used for processing the catalytic cracking unit of heavy charge at petrochemical plant,, make the temperature of device very high, destroyed normal technical process because catalyst will be emitted a large amount of heats in the course of reaction of burning.External warmer is set can be cooled off high temperature catalyst, guarantees steadily carrying out of technological operation; It can utilize this part superfluous heat generation steam simultaneously, thereby becomes important energy saving facility of device.External warmer is operated nimblely because the heat-obtaining amount is big, and commercial Application is very extensive.

Existing external warmer roughly has three kinds of patterns, all has the improved place of some needs.First kind is the external warmer of similar shell-and-tube heat exchanger pattern, and as U.S. Pat 5,209,287, its heat-transfer pipe is thinner, and water and steam are derived water introducing and a steam (vapor) outlet with a water inlet more separately by a bobbin carriage with steam.Catalyst is walked shell side, and is vertically dirty along tube wall, and the bottom is provided with fluidized wind with catalyst fluidization.The compact conformation of this external warmer, heat transfer area is big.Shortcoming is that the heat-transfer pipe tube wall is thinner, is easy to by catalyst worn outly, in case a heat-transfer pipe is worn out, whole external warmer lost efficacy, and changed very difficult.

Second kind is unit pipes group header type external warmer, and as Chinese patent ZL90101048.0, it is made up of housing and some heat transfer unit pipe groups, the slightly larger in diameter of heat-transfer pipe, each unit pipes group comprises many heat-transfer pipes, is pooled together by upper header and lower collecting box, draws housing from top then.This external warmer characteristics are that catalyst fluidization is in good condition, and each unit pipes group respectively has valve control, opening and closing voluntarily, and the heat-transfer pipe of a unit pipes group is out of joint, does not influence the use of whole heat collector.Shortcoming is that the heat-transfer pipe between the upper and lower header at high temperature nonvolatil torsional deformation takes place easily and influences its service life.Little owing to the header size in addition, opening is big, and weld seam is more, and is in use easy to crack, therefore having relatively high expectations to the processing and manufacturing level.

More than the external warmer of two kinds of forms, its heat-transfer pipe is the optical surface type, is called for short light pipe.

The third is the fin-and-tube type external warmer, and its heat-transfer pipe diameter is bigger, and the surface is thick with longitudinal fin, and every finned tube also is an independently heat transfer element.When this external warmer was in dilute phase stream at catalyst, result of use was better, but when catalyst was in the fluid bed of close phase, the dense-phase catalyst between the fin was difficult for fluidisation, formed " dead interlayer " easily, had seriously undermined heat-transfer effect.

It is worn out by catalyst easily that the purpose of this utility model is to solve above-mentioned heat-transfer pipe, heat-transfer pipe easy deformation between the tube bank header, problems such as easy cracking of tube bank header and heat transfer efficiency are not high, a kind of external warmer of improved ailhead heat-transfer pipe pattern is provided, make it not only have advantages of good abrasion and reliability, and have higher heat transfer efficiency.

Specify design feature of the present utility model and embodiment below in conjunction with accompanying drawing.

Fig. 1 is the structural representation of the utility model external warmer.

Fig. 2 is the structural representation of ailhead heat-transfer pipe.

As shown in Figure 1, the utility model is a kind of external warmer that comprises heat-transfer pipe and housing, and one or more ailhead heat-transfer pipe 4 is arranged, and places within the vertical cylindrical housings 5; Each root ailhead heat-transfer pipe is an enclosed construction, steam jacket 2 by feed pipe 1 and band ailhead 11 is formed, and constitutes one and has the independently heat transfer unit in water-vapour loop, and each root ailhead heat-transfer pipe one end is fixed on the end socket 12, the other end is positioned in the housing by locating rack 6, retractable.Catalyst inlet pipe 9, the inlet tube of catalyst outlet pipe 8 and fluidized wind distributor 7 all is arranged on the housing 5, and fluidized wind is entered in the process system pipeline by gas return port 3, and the inwall of housing 5 has the thermostable heat insulation wear resistance lining.

As shown in Figure 2, the steam jacket of every ailhead heat-transfer pipe (2) is made up of parent tube 10 and ailhead 11, staggered parent tube surfaces that are distributed on of ailhead 11, and vertical with the parent tube surface, ailhead 11 be straight sprig head shown in Fig. 2 (a), or be that L sprig head is shown in Fig. 2 (b); The diameter of ailhead is 6～12mm, highly is 25～35mm; The area on topped parent tube surface, ailhead cross section is less than 25%.

The course of work that the utility model external warmer is used for catalytic cracking unit is as follows: as shown in Figure 1, the high temperature catalyst that comes from the catalytic cracking unit regenerator enters the utility model external warmer from catalyst inlet pipe 9, in heat collector, form one section dense-phase bed, fluidized wind then enters beds by the fluidized wind distributor 7 of bottom, make catalyst be in fluidized state, thereby strengthened the exothermic effects of high temperature catalyst ailhead heat-transfer pipe 4.The cooled catalyst of heat release enters the catalytic cracking unit regenerator by the catalyst outlet pipe, thereby has finished the cool cycles process of catalyst in the utility model external warmer.The top of the feed pipe 1 of every ailhead heat-transfer pipe 4 a water inlet arranged, a saturated vapor outlet is arranged at the top of heat transfer sleeve pipe 2, every one of each self-forming of ailhead heat-transfer pipe has the independently heat transfer unit in water-vapour loop, the superfluous heat that high temperature catalyst is taken out of from the catalytic cracking unit regenerator, the saturated vapor that produces by the ailhead heat-transfer pipe is constantly taken away like this.

The utility model compared with prior art has following features owing to adopt above-mentioned ailhead heat transfer tube configuration:

(1) the catalytic cracking unit external warmer all is used for taking place saturated vapor, the inboard heat transfer coefficient of heat-transfer pipe than The outside is much bigger, and the thermal resistance of heat-transfer pipe is mainly from the outside, and namely catalyst is to the heat release of heat-transfer pipe tube wall. This reality With novel ailhead heat-transfer pipe, because the effect of ailhead has increased the heat transfer area in the pipe outside, the opposing party on the one hand Face is perpendicular direction because ailhead and catalyst flow, and can produce local turbulent flow, has strengthened heat-transfer effect, thereby tool Higher heat-obtaining efficient is arranged, and the heat-obtaining amount is big. Simultaneously since the parent tube surface area that the ailhead cross section covers less than 25%, Substantially the characteristics that kept light pipe can not affect again flowing of catalyst.

(2) because every ailhead heat-transfer pipe is an independently heat transfer element, can be suitable for the requirement of different heat-obtaining amounts.

(3) rigidity of heat-transfer pipe is bigger, and is not yielding under the high temperature, has mar proof and reliability preferably.

(4) heat-transfer pipe handling ease, cost is relatively low.

(5) external warmer of the ailhead heat-transfer pipe pattern that provides of the utility model is not only applicable to catalytic cracking unit, and can be applicable to have other petrochemical plants of similar requirement.

Claims (6)

1, a kind of external warmer that comprises heat-transfer pipe and housing is characterized in that having one or more ailhead heat-transfer pipe (4), places within the vertical cylindrical housings (5); Each root ailhead heat-transfer pipe is an enclosed construction, is made up of the steam jacket (2) of feed pipe (1) and band ailhead (11), constitutes one and has the independently heat transfer unit of vapour circuit; Every described ailhead heat-transfer pipe one end is fixed on the end socket (12), and the other end is positioned in the housing retractable by locating rack (6); The inlet tube of catalyst inlet pipe (9), catalyst outlet pipe (8) and fluidized wind distributor (7) all is arranged on the housing (5), and fluidized wind is discharged by gas return port (3).

2, external warmer as claimed in claim 1 is characterized in that every steam jacket (2) is made up of parent tube (10) and ailhead (11), the staggered parent tube surface that is distributed on of ailhead (11), and vertical with the parent tube surface.

3,, it is characterized in that described ailhead (11) can be straight sprig head or L sprig head as claim 1 and 2 described external warmers.

4, external warmer as claimed in claim 3, the diameter of described ailhead are 6～12mm, and the height of ailhead is 25～35mm.

5, external warmer as claimed in claim 1, the area that its ailhead cross section covers the parent tube surface is less than 25%.

6, external warmer as claimed in claim 1 is characterized in that the inwall of housing (5) has the thermostable heat insulation wear resistance lining.

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