RO118820B1

RO118820B1 - After burner

Info

Publication number: RO118820B1
Application number: ROA200101170A
Authority: RO
Inventors: Lucian Mihăescu; Tudor Prisecaru; Alexandru Sorin Ene; Mălina Mihaela Prisecaru; Radu Popescu
Original assignee: Centrul De Cercetare Şi Expertizare Materiale Speciale (Cems) Din Universitatea Politehnică Bucureşti
Priority date: 2001-10-26
Filing date: 2001-10-26
Publication date: 2003-11-28

Abstract

The invention relates to an afterburner with reduced NOx emission, using the oxygen in the flue gases and in the cooling air as comburant. According to the invention, the burner wherein the gas burning is initially produced based on the mixture of the fuel gas and the cooling air introduced through the ventilator, and is finished based on the mixture of the product of burning with the discharged flue gases, comprises a main body (1) having a connection flange (2) at an end, and a ceramic frustum of a cone (3) as thermal stabilizer at the other end. The main body (1) has at exterior a channel (4) for the admission of the gas fuel, provided with boxes (5) for gas distribution, the admission channel (4) being surrounded by a cooling air channel (6) provided, in its turn, with boxes (7) for the cooling air distribution. Some V-arranged stabilizing plates (8), are mounted on the boxes (5) for gas fuel distribution. The gas fuel distribution is made through some orifices (9).

Description

RO 118820 ΒRO 118820 B

Invenția se referă la un arzător postardere, care folosește drept comburant oxigen din gazele de ardere și din aerul de răcire, destinat echipării cazanelor recuperatoare, utilizate în ciclurile termice cu turbine cu gaze, sau la cazanele recuperatoare care utilizează gaze de ardere provenite din alte surse energetice calde (cuptoare, motoare cu ardere internă etc.).The invention refers to an afterburner, which uses oxygen from combustion gases and cooling air as an oxidant, intended for equipping recovery boilers, used in gas turbine thermal cycles, or recovery boilers that use combustion gases from other sources hot energy (furnaces, internal combustion engines, etc.).

Sunt cunoscute arzătoare de gaz pentru reîncălzirea gazelor de ardere evacuate, arzătoare care sunt montate într-un canal de legătură a sursei de gaze de ardere evacuate cu cazanul sau cuptorul recuperator sau direct la cazan și care folosesc drept comburant oxigenul din gazele de ardere. Arzătoarele depind constructiv și funcțional de condițiile de temperatură și presiune ale gazelor de ardere de la sursă. Ca urmare, această soluție cere utilizarea unor materiale speciale și scumpe. întreruperea funcționării sursei de gaze de ardere povoacă dificultăți în exploatare, chiar dacă s-a prevăzut pornirea imediată a unui sistem de alimentare cu aer.Gas burners are known for reheating the exhaust gases, burners that are mounted in a channel connecting the source of exhaust gases to the boiler or recovery furnace or directly to the boiler and which use the oxygen from the combustion gases as oxidant. Burners are constructively and functionally dependent on the temperature and pressure conditions of the flue gases from the source. As a result, this solution requires the use of special and expensive materials. the interruption of the operation of the source of combustion gases causes difficulties in operation, even if the immediate start of an air supply system has been foreseen.

Arzătorul post ardere, conform invenției, înlătură dezavantajele menționate prin aceea că, pe niște cutii de distribuție a combustibilului gazos, sunt montate plăcuțe stabilizatoare, dispuse în formă de “V”, a căror geometrie și poziționare asigură efectul de stabilizare a flăcării pentru regimul de sarcină de 30...100%, la variația între 15 și 19% compoziție volumetrică a conținutului de oxigen în gazele de ardere comburante.The post-combustion burner, according to the invention, removes the disadvantages mentioned in that, on some gas fuel distribution boxes, stabilizer plates are mounted, arranged in a "V" shape, whose geometry and positioning ensure the flame stabilization effect for the regime of load of 30...100%, at the variation between 15 and 19% volumetric composition of the oxygen content in the combustion gases.

Avantajele aplicării invenției sunt următoarele:The advantages of applying the invention are the following:

- emisie scăzută de noxe;- low emission of noxes;

- obținerea unei arderi stabile și complete;- obtaining a stable and complete combustion;

- reducerea gabaritului cazanului recuperator;- reducing the dimensions of the recovery boiler;

- creșterea eficienței procesului de transfer termic cu circa 30%;- increasing the efficiency of the heat transfer process by about 30%;

- creșterea randamentului termic al instalației cu până la 15...20%, în funcție de tipul circutului sub presiune, de tipul recuperatorului și de întreaga concepție a instalației.- increasing the thermal efficiency of the installation by up to 15...20%, depending on the type of pressure circuit, the type of recuperator and the entire design of the installation.

în continuare, se dă un exemplu de realizare a invenției, în legătură cu fig. 1 și 2, care reprezintă:next, an example of the invention is given, in connection with fig. 1 and 2, which represent:

- fig.1, schița de ansamblu a arzătorului postardere;- fig.1, overall sketch of the afterburner;

- fig.1 a, vedere din direcția A a unei cutii de distribuție din alcătuirea arzătorului;- fig.1 a, view from direction A of a distribution box of the burner;

- fig.1 b, vedere din direcția B, a unei plăcuțe stabilizatoare, din alcătuirea arzătorului;- fig.1 b, view from direction B, of a stabilizing plate, from the composition of the burner;

- fig. 1c, vedere spațială din direcția C, a plăcuței stabilizatoare;- fig. 1c, spatial view from direction C, of the stabilizer plate;

- fig.2, schema funcțională a arzătorului.- fig.2, functional diagram of the burner.

Arzătorul postardere, conform invenției, se compune dintr-un corp principal 1, care are la un capăt o flanșă de legătură 2, la celălalt capăt, un trunchi de con ceramic 3, cu rol de stabilizator termic, iar la exterior, are un canal 4, de admisie a combustibilului gazos, prevăzut cu cutii 5, de distribuție a gazului. Canalul de gaz combustibil este înconjurat de un canal de aer 6, de răcire, prevăzut, la rândul său, cu cutii 7, de distribuție a aerului de răcire. Pe cutiile 5, de distribuție a combustibilului gazos, sunt montate plăcuțe stabilizatoare 8, dispuse în formă de “V”. Distribuția combustibilului gazos se face prin niște orificii 9, plasate pe fețele laterale ale corpului cutiei 5. Creșterea diametrului acestor orificii către exteriorul arzătorului asigură o viteză constantă a combustibilului, distribuită pe rază.The afterburner, according to the invention, consists of a main body 1, which has a connecting flange 2 at one end, a ceramic cone trunk 3 at the other end, with the role of a thermal stabilizer, and on the outside, it has a channel 4, gas fuel inlet, provided with boxes 5, gas distribution. The fuel gas channel is surrounded by an air channel 6, for cooling, provided, in turn, with boxes 7, for distribution of cooling air. Stabilizing plates 8, arranged in a "V" shape, are mounted on the boxes 5, for the distribution of gaseous fuel. The distribution of the gaseous fuel is done through some holes 9, placed on the side faces of the body of the box 5. The increase in the diameter of these holes towards the outside of the burner ensures a constant speed of the fuel, distributed on the radius.

Gazul comburant este introdus în arzător pe direcție axială, la exteriorul canalului 6, de aer de răcire. Amestecarea comburantului din gazele de ardere și combustibil are loc după ce acesta din urmă este injectat perpendicular pe direcția de curgere a curentului de aer de răcire, prin orificiile 9.Combustible gas is introduced into the burner in an axial direction, on the outside of the cooling air channel 6. The mixing of the combustor from the combustion gases and fuel takes place after the latter is injected perpendicular to the direction of the cooling air flow, through the holes 9.

Aerul este evacuat din cutiile de distribuție 7, spre jeturile de combustibil gazos, prin orificii dimensionate astfel, încât să asigure condiții de amestec stoichiometric în zona de aprindere, în prima treaptă de ardere. Orificiile 9, pentru gazul combustibil, sunt astfel dimensionate, încât să permită o viteză mare de pătrundere în gazele de ardere comburante, în a doua treaptă de ardere.The air is discharged from the distribution boxes 7, towards the gaseous fuel jets, through holes sized in such a way as to ensure stoichiometric mixing conditions in the ignition zone, in the first stage of combustion. The holes 9, for the fuel gas, are sized in such a way as to allow a high speed of penetration into the oxidizing combustion gases, in the second stage of combustion.

Claims

RO 118820 B

Combustion of the gas is initially obtained due to the mixture between the fuel gas and the cooling air, and is completed due to the mixture of the combustion product with the combustion gases. Cooling air comes from a low-pressure circuit and is introduced into the pre-flame area to ensure control of the carbon monoxide combustion process - bearing in mind that, in general, combustion with an oxygen concentration below 21% in the horn agent - 55 burant is susceptible to high emission of carbon monoxide. The stabilization of the flame is achieved as a result of the recirculation currents behind the stabilizing plates, which can be curved or straight, with the size and positioning strictly related to the thermal capacity of the burner in question, as well as to the concentration of oxygen in the combustion gases.

The geometry and positioning ensure the flame stabilization effect for the regime of 60 load 30...100% at the variation between 15 and 19% (volumetric composition) of the oxygen content in the oxidizing combustion gases. The transverse surface of the plates covers 30...40% of the flow surface corresponding to the hydraulic diameter of the burner.

During the operation of the burner, the pulsations due to the variation of the load of the combustion gas source are significantly attenuated, as a result of the existence of the stabilizer plates, and as a result of 65 air cooling, the burner does not use special materials.

demand

1. Post-combustion burner, intended for equipping recovery boilers used in 70 thermal cycles with gas turbines or recovery boilers that use combustion gases from other hot energy sources (furnaces, internal combustion engines, etc.), which uses oxygen from the combustion gases and from the cooling air, consisting of a main body, which has a connecting flange at one end, and a ceramic cone trunk at the other end, on the outside it has a gaseous fuel inlet channel and a channel of 75 cooling air, which surrounds the gaseous fuel intake channel, both channels being provided with distribution boxes, characterized by the fact that stabilizing plates (8) are mounted on the gaseous fuel distribution boxes (5), arranged in a "V" shape ", whose geometry and positioning ensure the flame stabilization effect for the load regime of 30...100%, at the variation between 15 and 19% volumetric composition of the oxygen content 80 in the oxidizing combustion gases.

2. Afterburner, according to claim 1, characterized in that a first stage of combustion is ensured by the introduction of cooling air before the injection of gaseous fuel, and a second stage of combustion is carried out by the oxygen from the oxidizing combustion gases, which leads to reduce the emission of nitrogen oxides. 85

The president of the examination committee: Eng. Constantin Cârstea

Examiner: Eng. Adina Ciurea