ITAS DUCTFLAME-F ENGINEERING MANUAL (METRIC)

EMDFFM-20200706

ITAS DUCTFLAME-F

ENGINEERING MANUAL (METRIC)

Version July 2020

The information provided on this brochure is for information purposes only and does not constitute any legal obligation or a warranty, expressed or implied,

concerning quality, marketability or suitability for a specific purpose.

Copyright © 2020 - Fives - All rights reserved. July 2020

Copyright Copyright 2020 by Fives ITAS S.p.A. All rights reserved. This publication is protected and shall not be copied, distributed, transmitted, transcribed or translated in any form or by any means, to any third parties, without the express written consent of Fives ITAS S.p.A. Disclaimer / Responsibility declining The manufacturer will decline all responsibilities for damages to the product, machine or production or injuries to persons in any of the following cases:

- Improper use of the product; - Use of the product by non-qualified personnel; - Not following regulations of the country where the product is installed; - Improper erection of the product; - Improper integration of the product into any machine; - Use of parts other than manufacturers parts or advised by manufacturer; - Maintenance by unskilled personnel; - Exceptional events; - Not following instructions mentioned in this document.

Liability and warranty ITAS Ductflame-F burner is a “partly completed machinery” and cannot be used without further integration into a combustion system or machine. Fives ITAS S.p.A. liability limits to the product only. Fives ITAS S.p.A. will not be liable for any injury, loss, damage or expense (whether direct or consequential), including but not limited to loss of use, income, or damage to material arising in connection with sale, installation, use of, inability to use or repair or replacement of Fives ITAS S.p.A. products. It is the intention of Fives ITAS S.p.A. of making this manual as accurate and complete as possible. In case any typos, mistakes, errors or missing elements were found in this document, please bring them to our attention so we can correct them. This document is under continuous supervision and modification of Fives ITAS S.p.A. document specialists. Therefore, it is the users’ responsibility to make sure they have the most recent version of documents at any time.

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TABLE OF CONTENTS

1. INTRODUCTION ........................................................................................................... 4

1.1 Audience ............................................................................................................................. 4

1.2 Symbols .............................................................................................................................. 4

1.3 Assistance .......................................................................................................................... 4

1.4 Related documents ............................................................................................................ 4

1.5 Purpose of this manual ...................................................................................................... 4

2. THE PRODUCT ............................................................................................................ 5

2.1 Description ......................................................................................................................... 5

2.2 Intended use ....................................................................................................................... 5

2.3 Certification ........................................................................................................................ 5

2.4 Mechanical construction.................................................................................................... 5

2.5 Functioning ......................................................................................................................... 6

2.6 Control methodology ......................................................................................................... 6

3. BURNER SELECTION AND SYSTEM DESIGN .......................................................... 7

3.1 Burner selection ................................................................................................................. 7

3.1.1 Process air check ................................................................................................................... 7

3.1.2 The nominal heat input of the burner system ....................................................................... 8

3.1.3 Determining the burner configuration ................................................................................... 8

3.2 Ignition ................................................................................................................................ 9

3.3 Flame safety ..................................................................................................................... 10

3.4 Process duct design ........................................................................................................ 10

3.4.1 Distance to the duct shell ......................................................................................................10

3.4.2 Process air velocity ...............................................................................................................10

3.4.3 Restriction plates ...................................................................................................................12

3.4.4 Duct lengths ...........................................................................................................................12

3.4.5 Process air safeguarding ......................................................................................................13

3.5 Gas valve train design ..................................................................................................... 13

3.6 Burner Management ......................................................................................................... 15

3.7 Typical schematic for ITAS Ductflame-F ....................................................................... 15

4. NOTES ........................................................................................................................ 16




1. INTRODUCTION

All involved personnel shall carefully read this entire manual before integrating the product into a combustion system. If any part of the information in this manual is not clear, contact Fives ITAS S.p.A. before proceeding. This manual provides information regarding the design of the burners for their specific design purpose. Do not deviate from any instructions or application limits described herein without written approval from Fives ITAS S.p.A.

1.1 Audience

This manual is intended for engineers having experience with all aspects of combustion. These aspects include, but are not limited to, induct burners, nozzle-mixing and its related components such as gas trains, blowers and fans, burner management and air flow design.

1.2 Symbols

The warning signal used in this document indicates a subject requiring special attention when designing the combustion system. Improper design of the combustion system might result in death or injury when operating the system.

1.3 Assistance

Should the user need any assistance, contact the local Fives ITAS S.p.A. representative or contact the Headquarter:

Fives ITAS S.p.A. Via Metauro, 5 – 20900 Monza (MB) – Italy Tel. +39 039 27331

1.4 Related documents

This engineering manual is provided together with, and cannot be used without: - Technical datasheet of the ITAS Ductflame-F burner series. - Engineering manual of the ITAS Ductflame-F burner series (present document)

1.5 Purpose of this manual

The purpose of this document is to ensure a safe, effective and trouble-free selection of the Ductflame-F burner and to support a trouble-free design of the combustion system where the burner is to be integrated. This document is not applicable for other ITAS Ductflame burners.

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2. THE PRODUCT

2.1 Description

Fives ITAS Ductflame type F burner shall be installed inside a process air duct. Ductflame-F burners produce a uniform flame, ideal for heating low oxygen air flows and high temperature air flows without adding additional combustion air. In case of proper balance between oxygen level and temperature, the Ductflame-F design provides stable operation over a wide range of velocities, inputs and fuels.

2.2 Intended use

ITAS Ductflame-F burner is designed for use on a wide range of industrial direct air-heaters. Typical industrial applications are:

- Spray dryers in Ceramics industry - Combined heat and power in energy industry - Afterburners in Environmental industry - High temperature air heating in general industry

2.3 Certification

ITAS Ductflame-F burner complies with the EN746-2 and the machine directive 2006/42/EC. This can be confirmed by manufacturer’s Declaration of incorporation. ITAS Ductflame-F meets the technical specifications of the Eurasian Customs Union (EAC).

2.4 Mechanical construction

The burner is modular built. This entails an unlimited range of capacity inputs. Multiple burner modules are assembled together on one or more gas distribution headers. Each module of the main burner consists of a stabilization plate where process air flows into the combustion zone. A module in between 2 rows is a so-called “propagation module”. On each of the stabilization plates, a pair of nozzles are installed for gas injection into the process air flow. A side assembling plate or a process air duct completes the construction.

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Gas distributor AISI 316

Propagation Plate AISI 310

Burner Plate AISI 310




2.5 Functioning

After starting the process air fan and the fan for pilot air, the operator shall push the “start” button. The burner control unit begins the start-up cycle, including safety checks, and opens the gas safety shut-off valves to allow gas supply towards the pilot burner and air supply towards the pilot burner. Gas and air flow through their separated ways towards the nozzle of the pilot burner. The combustible gas/air mixture is produced at the pilot nozzle. The gas/air mixture is electrically ignited by a spark electrode. A flame is produced, which will be monitored by a flame rod or UV-sensor. The burner control unit opens the safety shut-off valves to allow gas supply to the main burner. Gas flows through the burner’s gas header towards the nozzles of the burner. At the nozzle, the gas forms a combustible mixture with the oxygen from the process air. The gas/air mixture is ignited by the pilot flame. A flame is produced, which will be monitored by a UV-sensor. The pilot switches off.

2.6 Control methodology

ITAS Ductflame-F burner is designed for gas control. During operation, the gas flow is controlled via control valves applying the gas pressure data at the burner inlet as indicated in the burner data sheet.

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3. BURNER SELECTION AND SYSTEM DESIGN

Designing a Ductflame-F burner system is a process consisting of multiple steps. The process starts by selecting the right burner size and calculating the proper process air duct for this burner. Engineering the control system and gas- and air supply skids are significant steps.

3.1 Burner selection

The burner shall properly suit the heater or application where it is intent to be used on. Use ITAS technical datasheets when following the selection process. The user shall make sure to be consulting the most recent version of technical datasheets.

3.1.1 Process air check

The Ductflame-F burner operates only in case of correct balance between oxygen level and temperature of the incoming process air. The graph 1 in the technical datasheet shows the working area of the Ductflame-F burner. Do not operate the Ductflame-F burners outside the purple area of the graph, as this causes flame instability and unsafe situations. The purple area in this graph shows the relation between the minimum required Oxygen level in the incoming process air in relation to the minimum temperature of that process air. When operating in the grey area, ITAS Ductflame-L, Ductflame-R or Ductflame-HTC burners are a better solution since these have separate combustion air supply.

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Figure 3.1 – Working area of Ductflame-F burners

Calculation example: In this example the client’s process requires 18.500 Nm³/h to be heated from 400°C to 900°C. The process air is a recirculated flow from another process; therefore the oxygen level is reduced to 17%.

Graph 3.1 demonstrates that Ductflame-F is the correct burner for this job.




3.1.2 The nominal heat input of the burner system

Making a heat balance of the process is necessary to determine the required (=nominal) heat input from the burner into the heater. The required heat input is a result of the thermal balance between:

- Conditions of the upstream process air flowing through the burner’s process duct (composition, temperature).

- Required downstream conditions from the burner’s process duct to the client’s process.

- Type and conditions of the fuel gas used to operate the combustion system.

As far as the capacity data are concerned, it shall be noted that the capacities in kW and energies in kWh/m³ relate to net heating values (=lhv) of the fuels used.

3.1.3 Determining the burner configuration

The capacity output of the ductflame-F burner module depends on the oxygen level in the process air. Graph 2 of the technical datasheet reads the maximum capacity outlet at a certain oxygen level in the incoming process air. Calculate the required number of burner modules based on the input per module from the graph.

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Calculation example: (continuing above calculation example) In this example the client’s heat balance calculation shows that 4100 kW heat input is required for 18500 Nm³/h process air lift the temperature from 400°C to 900 °C.

Calculation example: (continuing above calculation example) With 17% oxygen content in the process air, the Ductflame-F offers up to 265 kWlhv output per burner module. The nominal capacity demand of 4100 kWlhv, divided by 265 kW per module, results in 15,5 modules. Round up to 16 modules. 16 modules can be positioned in 2 rows of 8. The propagation plate in between the rows completes the design, but it does not count for the capacity output of the burner.




The required number of modules can be placed in a certain layout. Figure 3.2 shows 18 burner modules divided over 3 rows + 2 propagation plates. When “shaping” the burner layout, consider the following: - Maximum 15 burner modules on a single row; - Add 1 module (propagation plate) between two rows;

The propagation plate is just for flame transfer between the rows, it does not count for the capacity output of the burner.

- The shape of the process air duct influences the burner layout. A rectangular burner fits best into a rectangular duct, a squarer burner fits better into a square process duct.

In case of required number of modules, the technical datasheet can be helpful to calculate the other parameters: - Maximum burner capacity: Number of burner modules *

kWlhv per module (from graph 2) - Nominal operating capacity: this is the capacity calculated

in 3.1.2 - Minimum burner capacity: number of modules * 15 kW

(burner turndown shall not be more than 10:1)

Never exceed the maximum and minimum capacities and process air temperatures as mentioned in the product’s technical datasheet. This might cause flame instability and

unsafe circumstances.

3.2 Ignition

ITAS Ductflame-F burners are ignited via one or more intermittent pilot burner. Each pilot burner has its own gas and air supply. The UV scanner installed on the pilot burner can be used for Pilot safeguarding and burner row safeguarding when the pilot has switched-off. Per 3 burner rows 1 pilot burner shall be installed. All pilot burners (and main gas connections) are installed on the same side of the burner. Your Fives ITAS representative may support in determining the correct pilot position.

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Calculation example: (continuing above calculation example) The technical datasheet shows that a 16 modules burner at 17% oxygen offers: Min capacity: 16 * 15 = 240 kW. Since the turndown gas shall not exceed 10:1, we consider minimum capacity 4100/10 = 410 kW for this example project.

Figure 3.2 – Ductflame-F with 18 modules + 2 propagation plates




3.3 Flame safety

ITAS Ductflame-F burners shall be safeguarded by UV-scanner(s). Make sure the type of UV-scanner is compatible with the burner control used in the burner management system. Also make sure that the signal is strong enough and wired separately from other components not to be disturbed. For detailed information on flame-scanner installation and connection, refer to the supplier’s literature. The number of flame scanners to be installed depends on local regulation and safety experiences by the supplier. In case of multiple burner rows, ITAS strongly recommends installing a flame-scanner on one of the other burner rows. At least each pilot point, the top row and the bottom row shall be safeguarded.

3.4 Process duct design

The installation of the burner into a properly designed process air duct improves the operation and lifetime of the burner and impacts the quality of the downstream process air. Duct dimensions are determined according to the process air-flow, required velocity and the burner configuration.

3.4.1 Distance to the duct shell

The minimum distance between the burner and the duct shell is 150 mm (figure 3.3).

3.4.2 Process air velocity

The minimum dimensions of the process air duct are determined by the allowable process air velocity over the burner. The larger the free space around the burner, the lower the velocity and the pressure drop related to the velocity. The higher the velocity (=higher pressure drop) the smaller the duct can be. The optimum fresh air velocity (>20% O2) over the burner is 10 m/s. Lower (as low as 5 m/s is possible) or higher (up to 13 m/s) velocities are possible, but it has negative impact on the uniformity of the downstream process flow.

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Figure 3.3 - Minimum distance to the duct shell

Calculation example: (continuing above calculation example) Following the instruction on chapter 3.2 and 3.3, the example burner requires 1 pilot and 2 UV scanners.

UV

Pilot + UV

Calculation example: (continuing above calculation example) Width of the burner (= length of the row) = 8 * 0,150 = 1,2 [m] Height of the burner (=2 rows + 1 prop. mod.) = 3 * 0,162 = 0,486 [m] Minimum duct size (considering the 150 mm space between burner and wall) Duct width: 1,2 + 0,15 + 0,15 = 1,5 [m] Duct Height: 0,486 + 0,15 + 0,15 = 0,786 [m]




The optimum recirculating air velocity (>11% O2) over the burner is 15 m/s. Lower (as low as 10 m/s is possible) or higher (up to 25 m/s) velocities are possible, but it has negative impact on the uniformity of the downstream process flow. To calculate the velocity of process air over the burner head, it is important to consider the sizes of the burner module, multiplied by the number of modules. Each burner module is blocking 0,150 m * 0,162 m = 0,0243m² of the duct area. To calculate the process air velocity over the burner, the following formulas might be used: Convert nominal flow conditions to actual conditions:

Qact = Qnom * (Tact / Tnom) * (Pnom / (Pact + 1013,25)) Qact = Actual flow [Am³/h] Qnom = Normalized flow [Nm³/h] Tact = Actual temperature of the process flow [K] Tnom = Normalized temperature = 20°C = 293 [K] Pnom = Normalized absolute pressure = 1013,25 [mbar] Pact = Actual pressure [mbar]

Calculate the velocity over the burner:

v = Qact / 3600 / Afree v = velocity around the burner [m/s] Qact = Actual flow [Am³/h] Afree = Free space around the burner [m²]

The pressure drop related to the calculated speed comes from the following formula: dP = (½ * ρ * v²)/100 dP = pressure drop [mbar] ρ (Rho) = density of the process air (environmental air, 20°C is 1,291 kg/m³) v = velocity around the burner [m/s]

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162

m

m

150

mm

Calculation example: (continuing above calculation example) Area blocked by the example burner = 16 * 0,15 * 0,162 = 0,389 [m²] Qnom = 18500 [Nm³/h] Tact = 400°C = 673 [K] Tnom = 293 [K] Pnom = 1013,25 [mbar] Pact = consider 2 in this example [mbar] Qact = 18500 * (673/293) * (1013,25/1015,25) = 42409 [Am³/h] Afree = duct area minus blocked by burner = (1,5 * 0,786) – 0,389 = 0,79 [m²] v = 42409 / 3600 / 0,79 = 14,9 [m/s] The process air velocity is within the allowable range (from 5 to 20 m/s).




3.4.3 Restriction plates

In some cases, it might be necessary to install restriction plates around the burner. These restriction plates are helpful to increase the velocity of the process air, while maintaining the 150 mm minimum distance to the duct shell. (figure 3.5)

3.4.4 Duct lengths

The design of the process air ducting before the burner’s process air duct shall be in order that the airflows are uniform. Poor uniformity of airflows can turn into noise, vibration, finally reduced lifetime of the burner and poor uniformity of flow and temperature downstream the burner. Inlet and outlet duct design is customer’s responsibility. Supplier cannot accept any responsibility for problems which may result from poorly designed ductwork. Ducting after the heater (Figure 3.6): The minimum straight length after the burner head shall be “flame length + 2 meters” Estimated flame lengths are specified in the technical datasheet. In case of a tapered duct, the minimum distance before transition is: - For rectangular ducts: one height or

width (whichever is larger). - For round ducts: one diameter

The transition duct shall not provide more than 7° taper (Figure 3.7);

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150

Restriction plates

Figure 3.5 - Restriction plates around the burner

Flame length +2m

Figure 3.6 - Downstream straight duct design

Figure 3.7 - Downstream tapered duct design




3.4.5 Process air safeguarding

To protect the burner against overheating and instability of flame, it is important to make sure (and safeguard) the availability of process air flowing over the burner. As soon as the process air drops down, the burner must switch off. See example figure 3.8

3.5 Gas valve train design

The gas valvetrain shall be designed in a proper and safe way to supply the correct amount of fuel gas at the right pressure to the burner. The required gas pressure at the inlet of the burner’s gas header can be read from the technical datasheet. The gas train shall comply with all local safety standards and codes. Regulations might be, but are not limited to:

- EN 746-2 and machine directive - NFPA with listing marks from UL, FM, CSA

The user shall make sure they are using high quality safety components and assemble these as per suppliers advise. Pipe diameters shall be selected correctly. High gas-flow velocities might create noise and high pressure-drops shall be avoided. Fives ITAS S.p.A. can support in the design and delivery of the main gas train for fuel supply to the burner.

Be sure the burner operates at proper gas- and air ratios. Too low air flow might cause uncomplete combustion, emission formation or other unsafe circumstances.

Install a pipe union or flange in the gas-line to the burner. This simplifies installation and removal of the burner during commissioning or maintenance and helps eliminating possible vibrations from the process into the combustion system. Fuel type: make sure the fuel is suitable for use on ITAS Ductflame-F burner. Natural gas net heating values shall be 8 kWh/Nm³ or higher.

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Figure 3.8 - Process air differential pressure switch




Fuel supply pressure: The gas pressure drop through the burner at maximum gasflow is given in the technical datasheet. To calculate a pressure for different inputs, the formula is:

p2 = p1 ∗ Q2

Q1

p1 = adjustment pressure for reference input [mbar] (from technical datasheet)* p2 = adjustment pressure for actual input [mbar] Q1 = reference input [kW] (from technical datasheet) Q2 = actual input [kW]

* The pressures indicated in the technical datasheet are based on the gases specified in that datasheet. A correction of the gas pressure at the burner when running natural gas with deviating caloric value and/or density may be necessary. The required pressure may be calculated with:

p2 = p1 ∗ 𝜌2

𝜌1∗

hv2

hv1

p1 = adjustment pressure for reference input [mbar] (from technical datasheet) p2 = adjustment pressure for actual input [mbar] ρ1 = density of reference fuel [kg/Nm³] (from technical datasheet) ρ2 = density of actual fuel [kg/Nm³] hv1 = heating value of the reference gas [kWh/m³] (from technical datasheet) hv2 = heating value of the actual gas [kWh/m³]

Pilot gas piping: Ductflame-F burner is provided with a pilot burner. Pilot burners shall be fed with gas -flow and -pressure as mentioned in the technical datasheet. For proper ignition of the pilot-burner, Fives ITAS S.p.A. recommends using a transformer with secondary voltage of 6 to 8 kVAC and a minimum secondary current of 20 mAmps at full wave output. During commissioning or maintenance of the burner, it may be necessary to move the pilot burner to reposition it for proper operation. The use of a flexible connection to the pilot allows such movement. The use of flexible pipes (expansion joints) are also recommended to absorb stress due to heat expansion and slight misalignment. Be aware that flexible pipe nipples might cause inaccurate measurements of pressures during commissioning. Capacity control: ITAS Ductflame-F burners are controlled via gas only. This entails that a valve with control motor shall be installed in the gas train. Fives ITAS can support in proper sizing of the valve. The required gas pressure at the inlet of the burner’s gas header can be read from the technical datasheet.

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Spark plug

Air pressure tap (P1) Gas adjusting Tee B

Gas adjusting Tee C

Rp ½” gas inlet

Rp 1” UV scanner connection

Gas pressure (Tap P2)

Sight glass Rp 1” Combustion air

Gas pressure (Tap P3)

Butterfly valve

Figure 3.9 - ITAS pilot burner




3.6 Burner Management

The combustion system shall be equipped with a management system. The management system must be in compliance with local regulations and shall be equipped with, but not limited to, burner relay, temperature safeguarding and pressure alarms. Contact Fives ITAS S.p.A. in case of questions or doubts.

3.7 Typical schematic for ITAS Ductflame-F

Figure 3.11 - PID ITAS Ductflame-F burner in duct

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4. NOTES

On this page personal engineering notes may be taken.

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ITAS DUCTFLAME-F ENGINEERING MANUAL (METRIC)