MXPA99008453A - Process for the combustion of hydrocarbon fuel in a bury - Google Patents

Abstract

The present invention relates to a process for combustion of hydrocarbon fuel in a burner that is exposed to a corrosive atmosphere, wherein the exterior surface of the burner is protected by passing a non-corrosive atmosphere along the exterior surface of the burner, characterized because the non-corrosive atmosphere consists of vap

Description

PROCESS FOR THE COMBUSTION OF HYDROCARBON FUEL IN A BURNER FIELD OF THE INVENTION The present invention is directed to the combustion of hydrocarbon fuel, in a burner, and to a device for carrying out the combustion process.

BACKGROUND OF THE INVENTION Hydrocarbon fuel, is commonly used in the chemical industry in the ignition of industrial furnaces and process heaters, and to supply heat to reactions that require heat and that are carried out in reaction vessels provided with appropriate burners. A general disadvantage of known burners is the damage to the exposed surface or face of the burner, at high speeds of the fuel gas, required for industrial burners, and the disintegration of the metal to dust caused by the corrosive atmosphere to which the burner is exposed. Burner surface at elevated temperatures. U.S. Patent No. 5,496,170 discloses a vortex flow burner with improved design to prevent hot combustion products from being internally recycled and combusting at a site adjacent to the exposed surface of the burner. Therefore, damage to the exposed surface of the burner caused by the hot combustion products is substantially prevented. It has now been observed that the disintegration of the metal to powder and the carburation of industrial burners which are subjected to a corrosive atmosphere, is substantially avoided when a protective atmosphere is directed along the outer surface and the exposed surface of the body of the burner, in an amount sufficient to dilute or displace the corrosive atmosphere around the surface of the burner.

DESCRIPTION OF THE INVENTION Accordingly, this invention consists of a process for combustion of hydrocarbon fuel, in a burner that is exposed to a corrosive atmosphere, wherein a non-corrosive atmosphere is passed along the exterior surface of the burner, to protect the surface of the contact with the corrosive atmosphere. The non-corrosive, suitable atmosphere will be any gaseous medium, which does not cause the metal to disintegrate to dust or carburetion reactions on the metal surfaces at an elevated temperature. Suitable non-corrosive atmospheres include vapor, H2, C02 and nitrogen, or mixtures thereof. In addition, the invention provides a burner for the combustion of hydrocarbon fuel with an oxidant, comprising within an outer metallic surface, conduits for supplying fuel and oxidant, and an orifice for combustion of the fuel with the oxidant, the improvement comprises a wall which surrounds, in a concentric and separate manner, at least part of the exterior metal surface of the burner and which is adapted to introduce and pass a protective atmosphere along the surface. When the above burner is operated in a reactor, the wall may be formed of a refractory lining material, in the upper part of the reactor, which surrounds the exterior surface of the burner, at a suitable distance and, therefore, forming a duct for the introduction and passage of the protective atmosphere during the operation of the burner. The following description shows, in more detail, a specific embodiment of the invention, with referensia to the drawing, in which the only Figure No. 1 shows a sectional view of a burner of the invention mounted on the upper part of a reactor. with refractory lining. A burner 2 having an outer surface with a cylindrical metal upper surface 4 and a conical metallic hole 6 is mounted on the upper part of a reactor 1. An annular space 10 which lies between the upper surface 4 and part of the orifice 6, is formed between the surface of the burner and a refractory lining 8 in the upper part of the burner 1. Through the annular space 10 steam is passed along the upper surface 4 and directed towards the orifice 6. The steam that is passed through the annular space 10 protects the outer surface of the combustion, corrosive atmosphere, and prevents the carburization or reaction of metallic clumping of the surface, caused by the atmosphere of the combustion.

Example In a pilot plant with an autothermal reformer (RAT), different embodiments of the compliance process were carried out in the invention, by using a type of burner such as that described in the North American patent.

No. 5,496,170. The burner has been protected against the disintegration of the metal to dust, on the exterior wall of the burner, with a current of steam that flows in a jacket that surrounds the burner. The external nozzle of the burner was made from an alloy that in preliminary experiments has been shown to be attacked by the disintegration of the metal to dust, without the presence of protective vapor flow, on the outside. At the same time, the operation of the individual burners with respect to soot formation was analyzed by determining the critical temperature for a certain ratio of steam to carbon (V / C). The critical temperature was found in each test by gradually lowering the exit temperature of the reactor (TSalida) until the soot limit was exceeded. In addition, the value for a burner without a protective vapor flow was determined, under otherwise identical conditions, i.e., the inlet flow, the operating pressure and the vapor to carbon ratio. The ratio of vapor to carbon (V / C) is defined as the sum of all vapor feeds in moles, divided by the sum of the hydrocarbons in moles of carbon atoms (C,). The pilot plant used in the previous tests or analyzes comprises units to supply the different feed streams to the RAT reactor, the RAT reactor and the equipment for the subsequent treatment of the product gas. The feed currents consisted of natural gas, steam, oxygen and hydrogen. All gases were compressed to operating pressure and preheated to operating temperature. In Table 1, an average composition of natural gas is provided. Natural gas was desulfurized before introduction to the RAT reactor. The feed currents were combined in three streams and passed to the RAT reactor pot. A first feed stream of natural gas, hydrogen and steam was preheated to a temperature of about 500 ° C. A second feed stream containing oxygen and steam was preheated to a temperature between 200 ° C and 220 ° C. A third feed stream consisting only of steam was heated to 450 ° C. In the RAT reactor, carried out a substoichiometric combustion and subsequently catalytic reforming reactions with steam and displacement reactions.The composition of the incoming and outgoing gas was analyzed by gas chromatography.The product gas was in equilibrium with respect to the reassessment of refurbishment and Displacement: Downstream of the RAT reactor, the process gas was cooled and most of the vapor content of the product gas condensed.

Table 1 Two analyzes were carried out using a burner manufactured from a Haynes-230 somersal alloy. This alloy was previously analyzed without a protective vapor flow on the exterior wall of the burner, under operating conditions, with a vapor to carbon ratio of 0.35 and 0.6, so that the exterior of the burner was attacked by the disintegration of the burner. metal to powder after approximately 155 hours of operation. The corresponding operating conditions, in tests or analyzes, with vapor protection, according to the invention, are summarized in Table 2 below. The type of burner above was analyzed with respect to the limits for the formation of soot, without vapor in the steam jacket, and this was carried out by the reference experiments "FFH V / C 0.60 ref." and "FFH V / C 0.35 ref." summarized below in Table 3. The soot limit was then investigated, when a certain portion of the steam was passed through the steam jacket, along the exterior wall of the burner. The operating conditions for the test or performance analysis with respect to soot formation (FFH) are shown in Table 3 together with the critical temperatures (tCrítics) < 3ue characterize the operation of the burner with respect to the formation of soot.

Table 2 The test or analysis of disintegration of the metal to powder is carried out with a steam to sarbon (V / C) ratio of 0.60 (DMP V / C 0.60) and 0.35 (DMP V / C 0.35), respectively. The operating conditions are summarized in the Table, where TEntrada •, and TEntrada 2 are the inlet temperatures of the first and second feed currents, respectively, and TSalida and PSalida, are the temperature and the pressure of the gas that leaves the reactor, conditions in which the steam reforming and displacement reactions are in equilibrium. After each test, the RAT reactor burner is removed for inspection. While the burner without protestor vapor flow on the outer wall, showed a region, on the surface, that was corroded by the disintegration of the metal to dust, on the outer surface of the gas nozzle, the outer nozzle of the burners are protective vapor did not show signs of disintegration of the metal to dust, on the outer surface.

Table 3 Operating conditions and critical temperatures (Tcritics) for performance experiments with respect to soot formation (FFH) including reference experiments without vapor in the vapor jacket.

To investigate the operation of the burner with respect to soot formation, four experiments have been carried out to determine the critical temperature (Critical) for operation with a steam flow in the steam jacket. The four experiments are carried out at a vapor to carbon ratio of 0.60 and 0.35, as shown in Table 3, where the critical temperature (Tcrftica) is shown as such. The flow of steam in the jacket was varied, as well as the steam flow for the first feed soruent, to maintain the total steam flow for the constant process. The results are compared with the results for burners of the same type set to work without a steam jacket (reference analysis). No evidence of signifisative differences was found. Thus, the funsionamiento is a flow of steam in a steam jacket on the outside of the burner, in an amount corresponding to 8 to 35% of the total amount of steam introduced to the proseso, does not influence the burner's operation as opposed to the burner. soot formation.

Claims (7)

NOVELTY OF THE INVENTION Having dessrito the invention that antesede, sonsidera is considered novelty, and therefore, resides as property contained in the following: CLAIMS

1. A process for the combustion of hydrocarbon fuel in a burner that is exposed to a corrosive atmosphere, because the outer surface of the burner is protected by passing a non-sorptive atmosphere along the outer surface of the burner.

2. The process according to claim 1, characterized in that the non-sorptive atmosphere consists of steam, H2, C02, nitrogen or mixtures thereof.

3. The process according to claim 1, characterized in that the hydrosarburent is burned are also vapor.

4. The sonsis process is the vindication 2, sarasterized because the non-corrosive atmosphere consists of steam.

5. The sonicity process is claim 3, which is sarasterized because at least part of the vapor is added to the hydrocarbon fuel, together with the non-corrosive atmosphere.

6. The burner for the combustion of hydrocarbon fuel are an oxidant, which forms within a superfisie exterior metalissa, passages for supplying fuel and oxidant, and an orifice for the sombustible of the fuel are the oxidant, and a surrounding wall, in a way singlestrisa and separated, at least part of the exterior metallurgy of the burner, and which is adapted to introduce and pass a protective atmosphere along the surface.

7. The compliance burner is claim 6, sarasterized because the wall is formed of refractory lining material.