WO2016192307A1

WO2016192307A1 - Novel heating furnace having multi-hearth structure, and design method and use thereof

Info

Publication number: WO2016192307A1
Application number: PCT/CN2015/094200
Authority: WO
Inventors: 李苏安; 邓清宇; 王坤朋
Original assignee: 北京中科诚毅科技发展有限公司
Priority date: 2015-06-01
Filing date: 2015-11-10
Publication date: 2016-12-08
Also published as: CN104896926A; CN104896926B

Abstract

Provided are a novel heating furnace having a multi-hearth structure, and method and use thereof. The heating furnace comprises a feed channel (1), a combustor (2), a furnace body and a collection outlet channel (7). The number of the combustor (2) is one. The furnace body comprises at least two hearths (3, 4) therein. An inlet of each hearth (3, 4) comprises a heat-insulated switch-board (10, 11) capable of being opened and closed. Remote differential pressure gauges (8, 0) are respectively provided between an inlet and an outlet of each hearth (3, 4). A feed space (13) is formed between the combustor (2) and the hearths (3, 4). The feed channel (1) communicates with the feed space (13). Each hearth (3, 4) comprises an outlet channel (5, 6). A heat-insulating filler is filled between the adjacent hearths (3, 4). Without changing a furnace tube configuration, a furnace tube material and the number of the combustor, when a hearth has a problem, a heating operation can be timely switched to another hearth without suspending normal operation for a heating furnace overhaul, thereby extending an operation suspension interval of a device required by the heating furnace overhaul, improving operation stability of the device, and eliminating a need of installing a spare furnace and accordingly reducing the cost.

Description

Novel heating furnace with multi-furnace structure and design method and use thereof

Technical field

The invention relates to a novel heating furnace with a multi-furnace structure, belonging to the fields of petrochemical and coal chemical industry.

Background technique

The heating furnace is a heating device widely used in the petroleum, chemical, metallurgy, electric power and natural gas industries. Its function is to fuel oil or gas and heat the oil or other medium. To meet the temperature requirements of downstream equipment for process logistics. In the petrochemical industry, tubular heating furnaces have been widely used as a means of providing heat for petrochemical production.

The tubular heating furnace generally consists of a radiation chamber, a convection chamber, a waste heat recovery system, a burner, and a ventilation system. The radiant chamber and the convection chamber are equipped with a furnace tube. This part is directly subjected to flame grilling and has the highest temperature. The possibility of coking in the tube must be fully considered. A burner is placed at the bottom, side chamber or top of the radiation chamber, and a baffle is placed in the chimney. The low temperature material first flows into the convection chamber furnace tube, and then flows through the radiant chamber furnace tube, and absorbs heat in the furnace chamber to become a high temperature material and flows out.

The furnace tube is an important component of the furnace for heat transfer. The furnace tube runs under severe conditions and directly sees the fire. Since it is impossible to design a high safety factor (otherwise, the furnace tube will be too thick), it is more susceptible to damage than other common equipment in the factory. The main forms of furnace tube damage are: tube wall thinning, deformation, cracking, bulging, internal and external corrosion.

Reducing the maintenance cycle and even damaging the heating furnace tube are caused by a combination of factors, among which in-tube corrosion and coking are the main reasons. Corrosion refers to the chemical corrosion caused by acidic or alkaline substances contained in the heating medium to the furnace tube; coking is a phenomenon in which the temperature of the oil in the furnace tube exceeds a certain limit and then thermally cracks to become free carbon and accumulate on the furnace tube.

In recent years, with the continuous increase of crude oil extraction and the continuous reduction of conventional crude oil reserves, the trend of crude oil inferiority has become more and more serious. The middle distillate obtained by direct distillation of crude oil and crude oil and the secondary fraction obtained by secondary processing such as coking and catalytic cracking have gradually increased the S and N contents, and the hydrocarbon molecular chain gradually becomes longer, which is the performance of the heating furnace and the heating furnace tube. Put forward a bigger test. Coal liquefaction and oil-coal mixing processes are processes that have higher molecular weight and higher S and N contents. Therefore, these processes are also subject to the same problems of corrosion and coking.

How to solve the problems caused by unstable operation, low starting load and even frequent maintenance and repair caused by corrosion and coking of the furnace tube has become a research hotspot. At present, the focus of the research is mainly on how to reduce the damage caused by corrosion and coking of the furnace tube. For example, related patents propose to extend the furnace tube form in the furnace tube, apply heat-resistant layer inside and outside the furnace tube, and add protective parts. The long furnace life, which can reduce the damage caused by corrosion and coking, etc., but does not solve the problem of stopping the device due to regular cleaning of the coke in the heating tube. Most of the current chemical plants and refineries adopt the method of setting up a spare furnace to make up for the short-term operation of the furnace. This makes the investment and floor space greatly increased, and the preheating and switching operations of the furnace are very cumbersome.

It is the guiding ideology of engineering design to ensure the safe and stable operation of the device. It is the key to extend the maintenance cycle of the equipment.

Summary of the invention

In order to solve the problems of the prior art, the present invention proposes a novel heating furnace with a multi-furnace structure, which automatically or manually switches to another furnace when the heating furnace tube in one furnace is affected by factors such as corrosion, coking and clogging. Achieving continuous operation, which fundamentally solves the problem of stopping the device due to coking of the tube.

The technical solution of the present invention is as follows:

A novel heating furnace of a multi-furnace structure, comprising a feed pipe, a burner, a furnace body and an outlet pipe, characterized in that the burner is one, and the furnace body comprises at least two, preferably 2-3 Furnace; each furnace inlet includes an openable and heat-insulating switchboard; each furnace is provided with a remote pressure differential meter between the inlet and the outlet; a feed space is included between the burner and the furnace, A feed conduit opens into the feed space; each furnace includes an outlet conduit, and an insulating packing is included between adjacent furnaces.

The burner is preferably a strong mixing burner.

Preferably, when the pressure drop of the remote pressure differential gauge exceeds 0.05-1 MPa, the switching plate of the furnace being used is closed, and the other furnace is opened.

The switching plates of different furnaces can be switched by automatic or manual double switching system of the furnace.

The state of the medium in the furnace is pure liquid phase, pure gas phase, gas-liquid two-phase flow, gas, liquid, solid three-phase flow or phase change in the furnace.

The heating method of the above novel heating furnace is characterized in that it comprises the following steps:

Opening the switching plate of one of the furnaces, the raw material enters the feeding space through the feeding pipe first and then enters the furnace through the open switching plate, the burner heats the opened furnace; and the opened furnace is monitored by the remote pressure differential meter Pressure drop, when the pressure drop exceeds the set value, preheating the other furnace; then the outlet duct of the other furnace is opened; then the switchboard of the original furnace is closed, and the other furnace switchboard is opened Then, the outlet pipe valve of the original furnace is closed; the original furnace is used for cleaning, cooled, and repaired while the other furnace is working.

The set value is preferably from 0.05 to 1 MPa.

The use of the above novel heating furnace is characterized in that it is used in a refinery in a refinery, a residuum furnace for refining, a residue hydrotreating or a coking and hydrogenation of oil and coal.

Also included is a method of designing a novel furnace of the multi-furnace structure described above.

Technical effect:

The invention provides a novel heating furnace with multi-furnace structure. When the heating furnace tube in one furnace is affected by factors such as corrosion, coking and clogging, it is automatically or manually switched to another furnace to realize continuous operation, which is basically The problem of stopping the device due to coking of the furnace tube is solved. The burner is a strong mixing burner, the number is only one, and the remote inlet and outlet pressure gauges of the single furnace are set to detect the blockage in the furnace tube. When the pressure drop exceeds the set value (0.05-1MPa), the switchboard is started. , you can switch the furnace. After the furnace is closed, the furnace is purged with steam, the factory is purged with air, and naturally cooled to normal temperature for maintenance. Since the switching plates are insulated and the insulation is also included between the furnaces, the heating of the other open furnace does not affect the maintenance of the closed furnace.

The invention can be switched to another furnace for heating in a situation where there is a problem in the furnace without changing the configuration of the furnace tube, the material of the furnace tube and the number of burners, without stopping the maintenance of the whole heating furnace, and prolonging the operation. The cycle of stopping the device due to the maintenance of the heating furnace improves the stability of the operation of the device, and does not require more spare furnaces, thereby greatly reducing the cost.

1. The maintenance time of the heating furnace is greatly extended, which is beneficial to the safe operation of the furnace;

2. The degree of automation of furnace switching is high and easy to operate;

3, retain manual switching, more secure;

4. Compared with the parallel setting of the standby heating furnace, since the expensive equipment such as burners is saved, the equipment investment can be saved by 30-50%, and the engineering investment is saved by 40-70%;

5. Save more than 60% of the area compared to the parallel heating furnace.

Since the process of residue hydrogenation and oil-coal mixing is a medium having a larger molecular weight and a higher S and N content, these processes are more prone to corrosion and coking, and the furnace has a high inspection rate, so the present invention is particularly The heating procedure applicable to the above process is more effective than setting the heating furnace in parallel.

DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic view of an embodiment of a double furnace of the present invention.

The labels in the figure are listed as follows:

1-feed pipe, 2-burner, 3-A furnace, 4-B furnace, 5-A furnace outlet pipe, 6-B furnace outlet pipe, 7-furnace outlet main pipe, 8-A furnace tube pressure difference Meter, 9-B furnace tube pressure difference meter, 10-A furnace switch board, 11-B furnace switch board, 12-combustion gas feed port, 13-feed space.

detailed description

In order to better explain the present invention, the present invention will be further explained below in conjunction with the specific embodiments and the accompanying drawings.

Example

This embodiment is applied to residue heating as shown in FIG. The furnace body includes an A furnace 3 and a B furnace 4; the burner 2 is a strong mixing burner, including a combustion gas feed port 12, which can heat both furnaces. Each furnace is respectively provided with a furnace tube pressure difference meter 8 and a furnace tube pressure difference meter 9 between the inlet and the outlet, and a feed space 13 is formed between the inlet pipe 1 and the inlet of the furnace. That is, the space inside the furnace between the burner 2 and the two furnaces, the material to be heated first enters the feeding space 13 after entering the furnace body from the feeding pipe 1, and the inlet of each furnace includes the heat insulating and opening and closing respectively. The A furnace switching plate 10 and the B furnace switching plate 11 , when the switching plate is opened, the materials enter the corresponding open furnace from the feeding space, and each furnace includes an A furnace outlet pipe 5 and a B furnace outlet pipe 6 respectively and is summarized as Furnace outlet main pipe 7. There are three layers of insulation filler between the furnaces. The insulation filler is made of high-temperature resistant aerospace ceramic material. The temperature of the unused furnace can be normal temperature, and the temperature range of insulation can reach 1200°C-1750°C.

Initial state: A furnace 3 is heated.

Switching condition: when the value of the A furnace tube differential pressure gauge 8 exceeds 0.1 MPa;

Preparation for switching: preheating furnace B with a small amount of combustion gas;

Switching process: (1) The differential pressure gauge transmits the signal to the pressure transmitter of the B furnace outlet pipe valve, and the B furnace outlet pipe 6 is opened; (2) The differential pressure meter transmits the signal to the furnace switching plate transmitter, A furnace switching The plate 10 is closed, and the B furnace switching plate 11 is opened; (3) the valve of the A furnace outlet pipe 5 is closed;

The switching is completed: the A furnace 3 is purged, naturally cooled, and repaired, while the B furnace 4 is heated. Follow the above procedure to cycle.

The above description is only a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily think of changes or substitutions within the technical scope of the present disclosure. For example, the number of furnaces, the size, the form of the switchboard, the form and connection of the pipes, etc., should be covered by the scope of the present invention. Therefore, the scope of the invention should be determined by the scope of the claims.

Claims

A novel heating furnace of a multi-furnace structure, comprising a feed pipe, a burner, a furnace body and an outlet pipe, characterized in that the burner is one, the furnace body comprises at least two furnaces; the inlet of each furnace The utility model comprises an openable and heat-insulating switchboard; each furnace is respectively provided with a remote pressure differential gauge between the inlet and the outlet; a feed space is arranged between the burner and the furnace, and the feed pipeline is connected to the Feed space; each furnace includes an outlet pipe, and an insulating filler is included between adjacent furnaces.
A novel heating furnace of a multi-furnace structure according to claim 1, wherein said furnaces are 2-3.
A novel furnace of a multi-furnace structure according to claim 1, wherein said burner is a strongly mixed burner.
A novel heating furnace of a multi-furnace structure according to claim 1, wherein when the pressure drop of the remote pressure differential gauge exceeds 0.05-1 MPa, the switching plate of the furnace being used is closed, and the other furnace is opened.
A novel furnace of a multi-furnace structure according to claim 1 including a furnace automatic and manual double switching system.
A novel heating furnace of a multi-furnace structure according to claim 1, wherein the state of the medium in the furnace is pure liquid phase, pure gas phase, gas-liquid two-phase flow, gas, liquid, solid three-phase flow or in a furnace A phase change occurs inside.
A heating method for a novel heating furnace having a multi-furnace structure according to any one of claims 1 to 6, characterized by comprising the steps of:

Opening the switching plate of one of the furnaces, the raw material enters the feeding space through the feeding pipe first and then enters the opened furnace through the open switching plate, the burner heats the opened furnace; the opening is monitored by the remote pressure differential gauge The pressure drop in the furnace, when the pressure drop exceeds the set value, preheating the other furnace; then the outlet duct of the other furnace is opened; then the switchboard of the original furnace is closed, and the other furnace is switched The plate is opened; the outlet pipe valve of the original furnace is closed; the original furnace is used for cleaning, cooled, and repaired while the other furnace is working.
The method of claim 7 wherein said set value is from 0.05 to 1 MPa.
The use of a novel heating furnace of a multi-furnace structure according to any one of claims 1 to 6, characterized in that it is used for decompression of a residue refining furnace, a residue hydrogenation or a coal-fired mixed hydrogenation in a refinery furnace.
A method for designing a novel heating furnace of a multi-furnace structure according to any one of claims 1 to 6, characterized in that the heating furnace is designed to have the following structure: a feed pipe, a burner, a furnace body, and an outlet pipe, the characteristics thereof There is one burner, the furnace body comprises at least two furnaces; the inlet of each furnace comprises an openable and heat-insulated switchboard; each furnace is provided with a remote pressure difference between the inlet and the outlet respectively. Between the burner and the furnace is a feed space, the feed conduit opens into the feed space; each furnace includes an outlet conduit, and an insulating filler is included between adjacent furnaces.