Development of Calculation Technique by Designing the Radiative Recu- perators Advanced in Frame of EUREKA Program

The EUREKA project «REPLACE NG» is focused on development and application of radiative (radiative-convective) recuperator of advanced design for heat recovery of flue gases by combustion the fuels including those of low calorific value (LCV gases) in the industrial furnaces of various types. It was...

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Опубліковано в: :Энерготехнологии и ресурсосбережение
Дата:2014
Автори: Sevcsik, M., Kapros, T., Sandor, P., Soroka, B.S.
Формат: Стаття
Мова:English
Опубліковано: Інститут газу НАН України 2014
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Онлайн доступ:https://nasplib.isofts.kiev.ua/handle/123456789/127294
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Цитувати:Development of Calculation Technique by Designing the Radiative Recu- perators Advanced in Frame of EUREKA Program / M. Sevcsik, T. Kapros, P. Sandor, B.S. Soroka // Энерготехнологии и ресурсосбережение. — 2014. — № 3. — С. 56-68. — Бібліогр.: 11 назв. — англ.

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Digital Library of Periodicals of National Academy of Sciences of Ukraine
id nasplib_isofts_kiev_ua-123456789-127294
record_format dspace
spelling Sevcsik, M.
Kapros, T.
Sandor, P.
Soroka, B.S.
2017-12-17T18:58:19Z
2017-12-17T18:58:19Z
2014
Development of Calculation Technique by Designing the Radiative Recu- perators Advanced in Frame of EUREKA Program / M. Sevcsik, T. Kapros, P. Sandor, B.S. Soroka // Энерготехнологии и ресурсосбережение. — 2014. — № 3. — С. 56-68. — Бібліогр.: 11 назв. — англ.
0235-3482
https://nasplib.isofts.kiev.ua/handle/123456789/127294
669.162.251:544.5
The EUREKA project «REPLACE NG» is focused on development and application of radiative (radiative-convective) recuperator of advanced design for heat recovery of flue gases by combustion the fuels including those of low calorific value (LCV gases) in the industrial furnaces of various types. It was supposed that the recuperators are suitable for preheating the flows of combustion air or LCV gases. Recuperators of both purposes could be used by installation at the furnaces fired with LCV gases. Mentioned equipment — recuperator of RRD type — was developed by Gas Institute of NASU (Ukraine). It was supposed accordingly preliminary program and schedule to involve Co. TUKI (Hungary) as the project partner for testing the recuperator arranged at the bell type furnace of Cold Rolling Mill Plant of ISD DUNAFERR Group under the furnace firing with different process gases (alternative fuels) originated by several metallurgical productions. The present paper demonstrates the proposed calculation technique suitable for comparison the thermal state of the new type heat exchangers and the radiative recuperators of traditional wide spread design basing upon computation of heat exchange processes within parallel-current and counter-current flows. The system of simplified differential one-dimensional heat balance and heat exchange equations was composed and used as the computation background. The computation model provides an opportunity to analyse an influence of heat transfer coefficients, mass and volume flow rates and heat fluxes by process of an air preheating due discovering and application the generalizing auxiliary dimensionless parameters. The advantages of new approach to the recuperators designing even by neglecting of an enhancement of heat transfer intensity from both sides of heat exchange surface(s) or from both media flows are connected with increase the heat exchange surface in case of recuperator of RRD type in comparison with ordinary one-stage radiative recuperators. Application of secondary (intermediate) adiabatic emitters arranged in channels for flue gases and air (or LCV gas) flows provides the additional opportunities.
Проект «REPLACE NG» («Замещение природного газа») направлен на разработку и использование радиационного (радиацинно-конвективного) рекуператора новейшей конструкции для утилизации теплоты уходящих газов при сжигании топлив, включая низкокалорийные (LCV) газы, в промышленных печах различного назначения. В соответствии с планом работ предполагалось, что разрабатываемые рекуператоры должны быть пригодны для нагрева воздуха горения и самих низко калорийных газов. Рекуператоры двойного назначения могут использоваться при установке на печах, отапливаемых низкокалорийным газом. Упомянутое оборудование — рекуператор типа РРД — разработано Институтом газа НАНУ (Украина). В соответствии с предварительной программой и графиком работ было намечено привлечение компании «ТЮКИ» (Венгрия) в качестве партнера по проекту на разных этапах, в частности, при испытаниях рекуператора, монтируемого с этой целью на колпаковой печи в цехе холодной прокатки комбината «ИСД ДУНАФЕРР». В ходе испытаний предусмотрено опробовать отопление печи различными технологическими газами металлургических производств (альтернативным топливом). В настоящей работе представлен вывод расчетных зависимостей, обеспечивающих прямое сравнение теплового состояния теплообменника нового типа и радиационных рекуператоров традиционной широко распространенной конструкции. Методика базируется на расчете процессов теплообмена в условиях прямо- и противоточного взаимного движения теплоносителей в каналах. Упрощенные дифференциальные уравнения теплового баланса и теплообмена для разных участков рекуператора были использованы в качестве базовой системы при получении расчетных зависимостей. Благодаря отысканию и применению обобщающих вспомогательных безразмерных параметров расчетная модель обеспечивает возможность анализа влияния коэффициентов теплообмена, массового и объемного потоков теплоносителей и тепловых потоков на результирующее температурное распределение в аппарате в процессе подогрева воздуха. Преимущества нового подхода к проектированию рекуператоров даже в случае пренебрежения ростом интенсивности теплообмена с обеих сторон теплообменной поверхности объясняются существенным увеличением области теплообмена (в случае рекуператора типа РРД) по сравнению с обычными одноходовыми радиационными рекуператорами. Использование вторичных (промежуточных) адиабатных излучателей в каналах для дымовых газов и воздуха (или потоков низкокалорийного газа) обеспечивает дополнительные возможности повышения подогрева воздуха (или низкокалорийного газа).
Проект «REPLACE NG» («Заміщення природного газу») направлений на розробку та використання радіаційного (радіаційно-конвективного) рекуператора новітньої конструкції для утилізації теплоти викидних газів при спалюванні палив, у тому числі низькокалорійних (LCV) газів, у промислових печах різного призначення. У відповідності до плану робіт передбачалося, що розроблювані рекуператори мають бути придатними до нагріву повітря горіння та самих низькокалорійних газів. Рекуператори подвійного призначення можуть використовуватися при установці на печах, опалюваних низькокалорійним газом. Таке обладнання — рекуператор типу РРД — розроблено Інститутом газу НАНУ (Україна). У відповідності до наміченої програми та графіка робіт було намічено залучення компанії «ТЮКІ» (Угорщина) як партнера по здійсненню проекта на різних етапах, а саме: при випробуваннях рекуператора, змонтованого з цією метою на ковпаковій печі у цеху холодної прокатки комбінату «ІСД ДУНАФЕРР». Під час досліджень передбачено випробувати опалювання печі різними технологічними газами металургійного виробництва (альтернативним паливом). У цій роботі представлено виведення розрахункових залежностей, які забезпечуватимуть пряме порівняння теплового стану теплообмінника нового типу та радіаційних рекуператорів традиційної широко розповсюдженої конструкції. Методика базується на розрахунку процесів теплообміну в умовах прямо- та протиточного взаємного руху теплоносіїв у каналах. Спрощенні диференційні рівняння теплового балансу та теплообміну для різних зон рекуператора були використані як базова система при отриманні розрахункових залежностей. Завдяки відшуканню та застосуванню узагальнюючих допом іжних безрозмірних параметрів розрахункова модель забезпечує можливість аналізу впливу коефіцієнтів теплообміну, масового та об’ємного потоків теплоносіїв та теплових потоків на результуючий температурний розподіл в апараті у процесі підігріву повітря. Переваги нового підходу до проектування рекуператорів, навіть не беручи до уваги зростання інтенсивності теплообміну з обох сторін теплообмінної поверхні, поясняються суттєвим збільшенням області теплообміну (у разі рекуператора типа РРД) у порівнянні зі звичайними одноходовими радіаційними рекуператорами. Використання вторинних (проміжних) адіабатних випромінювачів у каналах для димових газів та повітря (чи потоків низькокалорійного газу) забезпечує додаткові можливості підвищення підігріву повітря (чи низькокалорійного газу).
en
Інститут газу НАН України
Энерготехнологии и ресурсосбережение
Приборы и оборудование
Development of Calculation Technique by Designing the Radiative Recu- perators Advanced in Frame of EUREKA Program
Розробка методики розрахунку з метою створення високоефективного радіаційного рекуператора в рамках виконання програми «EUREKA»
Разработка методики расчета с целью создания высокоэффективного радиационного рекуператора в рамках выполнения программы "EUREKA"
Article
published earlier
institution Digital Library of Periodicals of National Academy of Sciences of Ukraine
collection DSpace DC
title Development of Calculation Technique by Designing the Radiative Recu- perators Advanced in Frame of EUREKA Program
spellingShingle Development of Calculation Technique by Designing the Radiative Recu- perators Advanced in Frame of EUREKA Program
Sevcsik, M.
Kapros, T.
Sandor, P.
Soroka, B.S.
Приборы и оборудование
title_short Development of Calculation Technique by Designing the Radiative Recu- perators Advanced in Frame of EUREKA Program
title_full Development of Calculation Technique by Designing the Radiative Recu- perators Advanced in Frame of EUREKA Program
title_fullStr Development of Calculation Technique by Designing the Radiative Recu- perators Advanced in Frame of EUREKA Program
title_full_unstemmed Development of Calculation Technique by Designing the Radiative Recu- perators Advanced in Frame of EUREKA Program
title_sort development of calculation technique by designing the radiative recu- perators advanced in frame of eureka program
author Sevcsik, M.
Kapros, T.
Sandor, P.
Soroka, B.S.
author_facet Sevcsik, M.
Kapros, T.
Sandor, P.
Soroka, B.S.
topic Приборы и оборудование
topic_facet Приборы и оборудование
publishDate 2014
language English
container_title Энерготехнологии и ресурсосбережение
publisher Інститут газу НАН України
format Article
title_alt Розробка методики розрахунку з метою створення високоефективного радіаційного рекуператора в рамках виконання програми «EUREKA»
Разработка методики расчета с целью создания высокоэффективного радиационного рекуператора в рамках выполнения программы "EUREKA"
description The EUREKA project «REPLACE NG» is focused on development and application of radiative (radiative-convective) recuperator of advanced design for heat recovery of flue gases by combustion the fuels including those of low calorific value (LCV gases) in the industrial furnaces of various types. It was supposed that the recuperators are suitable for preheating the flows of combustion air or LCV gases. Recuperators of both purposes could be used by installation at the furnaces fired with LCV gases. Mentioned equipment — recuperator of RRD type — was developed by Gas Institute of NASU (Ukraine). It was supposed accordingly preliminary program and schedule to involve Co. TUKI (Hungary) as the project partner for testing the recuperator arranged at the bell type furnace of Cold Rolling Mill Plant of ISD DUNAFERR Group under the furnace firing with different process gases (alternative fuels) originated by several metallurgical productions. The present paper demonstrates the proposed calculation technique suitable for comparison the thermal state of the new type heat exchangers and the radiative recuperators of traditional wide spread design basing upon computation of heat exchange processes within parallel-current and counter-current flows. The system of simplified differential one-dimensional heat balance and heat exchange equations was composed and used as the computation background. The computation model provides an opportunity to analyse an influence of heat transfer coefficients, mass and volume flow rates and heat fluxes by process of an air preheating due discovering and application the generalizing auxiliary dimensionless parameters. The advantages of new approach to the recuperators designing even by neglecting of an enhancement of heat transfer intensity from both sides of heat exchange surface(s) or from both media flows are connected with increase the heat exchange surface in case of recuperator of RRD type in comparison with ordinary one-stage radiative recuperators. Application of secondary (intermediate) adiabatic emitters arranged in channels for flue gases and air (or LCV gas) flows provides the additional opportunities. Проект «REPLACE NG» («Замещение природного газа») направлен на разработку и использование радиационного (радиацинно-конвективного) рекуператора новейшей конструкции для утилизации теплоты уходящих газов при сжигании топлив, включая низкокалорийные (LCV) газы, в промышленных печах различного назначения. В соответствии с планом работ предполагалось, что разрабатываемые рекуператоры должны быть пригодны для нагрева воздуха горения и самих низко калорийных газов. Рекуператоры двойного назначения могут использоваться при установке на печах, отапливаемых низкокалорийным газом. Упомянутое оборудование — рекуператор типа РРД — разработано Институтом газа НАНУ (Украина). В соответствии с предварительной программой и графиком работ было намечено привлечение компании «ТЮКИ» (Венгрия) в качестве партнера по проекту на разных этапах, в частности, при испытаниях рекуператора, монтируемого с этой целью на колпаковой печи в цехе холодной прокатки комбината «ИСД ДУНАФЕРР». В ходе испытаний предусмотрено опробовать отопление печи различными технологическими газами металлургических производств (альтернативным топливом). В настоящей работе представлен вывод расчетных зависимостей, обеспечивающих прямое сравнение теплового состояния теплообменника нового типа и радиационных рекуператоров традиционной широко распространенной конструкции. Методика базируется на расчете процессов теплообмена в условиях прямо- и противоточного взаимного движения теплоносителей в каналах. Упрощенные дифференциальные уравнения теплового баланса и теплообмена для разных участков рекуператора были использованы в качестве базовой системы при получении расчетных зависимостей. Благодаря отысканию и применению обобщающих вспомогательных безразмерных параметров расчетная модель обеспечивает возможность анализа влияния коэффициентов теплообмена, массового и объемного потоков теплоносителей и тепловых потоков на результирующее температурное распределение в аппарате в процессе подогрева воздуха. Преимущества нового подхода к проектированию рекуператоров даже в случае пренебрежения ростом интенсивности теплообмена с обеих сторон теплообменной поверхности объясняются существенным увеличением области теплообмена (в случае рекуператора типа РРД) по сравнению с обычными одноходовыми радиационными рекуператорами. Использование вторичных (промежуточных) адиабатных излучателей в каналах для дымовых газов и воздуха (или потоков низкокалорийного газа) обеспечивает дополнительные возможности повышения подогрева воздуха (или низкокалорийного газа). Проект «REPLACE NG» («Заміщення природного газу») направлений на розробку та використання радіаційного (радіаційно-конвективного) рекуператора новітньої конструкції для утилізації теплоти викидних газів при спалюванні палив, у тому числі низькокалорійних (LCV) газів, у промислових печах різного призначення. У відповідності до плану робіт передбачалося, що розроблювані рекуператори мають бути придатними до нагріву повітря горіння та самих низькокалорійних газів. Рекуператори подвійного призначення можуть використовуватися при установці на печах, опалюваних низькокалорійним газом. Таке обладнання — рекуператор типу РРД — розроблено Інститутом газу НАНУ (Україна). У відповідності до наміченої програми та графіка робіт було намічено залучення компанії «ТЮКІ» (Угорщина) як партнера по здійсненню проекта на різних етапах, а саме: при випробуваннях рекуператора, змонтованого з цією метою на ковпаковій печі у цеху холодної прокатки комбінату «ІСД ДУНАФЕРР». Під час досліджень передбачено випробувати опалювання печі різними технологічними газами металургійного виробництва (альтернативним паливом). У цій роботі представлено виведення розрахункових залежностей, які забезпечуватимуть пряме порівняння теплового стану теплообмінника нового типу та радіаційних рекуператорів традиційної широко розповсюдженої конструкції. Методика базується на розрахунку процесів теплообміну в умовах прямо- та протиточного взаємного руху теплоносіїв у каналах. Спрощенні диференційні рівняння теплового балансу та теплообміну для різних зон рекуператора були використані як базова система при отриманні розрахункових залежностей. Завдяки відшуканню та застосуванню узагальнюючих допом іжних безрозмірних параметрів розрахункова модель забезпечує можливість аналізу впливу коефіцієнтів теплообміну, масового та об’ємного потоків теплоносіїв та теплових потоків на результуючий температурний розподіл в апараті у процесі підігріву повітря. Переваги нового підходу до проектування рекуператорів, навіть не беручи до уваги зростання інтенсивності теплообміну з обох сторін теплообмінної поверхні, поясняються суттєвим збільшенням області теплообміну (у разі рекуператора типа РРД) у порівнянні зі звичайними одноходовими радіаційними рекуператорами. Використання вторинних (проміжних) адіабатних випромінювачів у каналах для димових газів та повітря (чи потоків низькокалорійного газу) забезпечує додаткові можливості підвищення підігріву повітря (чи низькокалорійного газу).
issn 0235-3482
url https://nasplib.isofts.kiev.ua/handle/123456789/127294
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AT sorokabs rozrobkametodikirozrahunkuzmetoûstvorennâvisokoefektivnogoradíacíinogorekuperatoravramkahvikonannâprogramieureka
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AT sorokabs razrabotkametodikirasčetascelʹûsozdaniâvysokoéffektivnogoradiacionnogorekuperatoravramkahvypolneniâprogrammyeureka
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fulltext 56 Ýíåðãîòåõíîëîãèè è ðåñóðñîñáåðåæåíèå. 2014. ¹ 3 � Sevcsik M., Kapros T., Sandor P., Soroka B.S., 2014 Ïðèáîðû è îáîðóäîâàíèå UDC 669.162.251:544.5 Sevcsik M.1, PhD, Kapros T.1, CSc, Sandor P.2, PhD, Soroka B.S.3, Doctor of Technical Science, Professor 1 TUKI R& D�� Company for Combustion Technology, Miskolc, Hungary 3515, Miskolc-Egyetemvaros, Pf.3, Hungary, e-mail: project@tuki.hu 2 «Optimum Energo-Ecologia» Ltd., Razalmash, Hungary Martinasz u.1,2459, e-mail:sandordr@vnet.hu 3 The Gas Institute of National Academy of Science of Ukraine, Kiev 39, Degtyarivska Str., 03113 Kiev, Ukraine, e-mail: b.soroka@gmail.com Development of Calculation Technique by Designing the Radiative Recuperators Advanced in Frame of EUREKA Program The EUREKA project «REPLACE NG» is focused on development and application of ra- diative (radiative-convective) recuperator of advanced design for heat recovery of flue gases by combustion the fuels including those of low calorific value (LCV gases) in the industrial furnaces of various types. It was supposed that the recuperators are suitable for preheating the flows of combustion air or LCV gases. Recuperators of both purposes could be used by installation at the furnaces fired with LCV gases. Mentioned equipment — recuperator of RRD type — was developed by Gas Institute of NASU (Ukraine). It was supposed accordingly preliminary program and schedule to involve Co. TUKI�� (Hun- gary) as the project partner for testing the recuperator arranged at the bell type furnace of Cold Rolling Mill Plant of ISD DUNAFERR Group under the furnace firing with dif- ferent process gases (alternative fuels) originated by several metallurgical productions. The present paper demonstrates the proposed calculation technique suitable for compari- son the thermal state of the new type heat exchangers and the radiative recuperators of traditional wide spread design basing upon computation of heat exchange processes within parallel-current and counter-current flows. The system of simplified differential one-dimensional heat balance and heat exchange equations was composed and used as the computation background. The computation model provides an opportunity to analyse an influence of heat transfer coefficients, mass and volume flow rates and heat fluxes by process of an air preheating due discovering and application the generalizing auxiliary dimensionless parameters. The advantages of new approach to the recuperators designing even by neglecting of an enhancement of heat transfer intensity from both sides of heat exchange surface(s) or from both media flows are connected with increase the heat ex- change surface in case of recuperator of RRD type in comparison with ordinary one-stage radiative recuperators. Application of secondary (intermediate) adiabatic emitters ar- ranged in channels for flue gases and air (or LCV gas) flows provides the additional op- portunities to increase an air (or LCV gas) preheat. Bibl. 11, Fig. 8, Table 2. Key words: bell type furnace, combustion air, combustion products (flue gases), counter-cur- rent flow, heat exchange coefficient, heat transfer coefficient, low calorific value fuel (LCV gas), parallel-current flow, radiative recuperator, temperature of heat transfer medium. 1. Presentation of the international project The «REPLACE NG» project has been sub- mitted to EUREKA program by international consortium under the co-ordination of the Gas Institute, NASU in the year 2011. The purpose of application made development of special fir- ing and heat recovery appliances suitable for use both in case of natural gas (NG) and the alter- native fuels (AF) use and promoting the substi- tution of NG for AF. The project has been ac- cepted by the EUREKA Forum in Brussels in June of 2011. The Research and Development Company TUKI�� has been recognized as the par- ticipating structure from the Hungarian side by the Project performing. One of the decisive tasks of the project is connected with the recuperators advancement re- sulting in development of updated designs of con- vective [1] and radiative [2] recuperators. Divi- sion of this heat exchange equipment by two mentioned types is conditional enough in princi- ple because of both constituents of heat transfer takes place under the plant operation. But the higher is working temperature of the furnace op- eration the higher would be radiation input. 1.1. Concept of development the novel types of heat recovery facilities. High- efficient two-passing radiative recupera- tors of RRD type (description). The distin- guished feature of the recuperators of both types accordingly Gas Institute’s proposal makes appli- cation of adiabatic (secondary, intermediate) emit- ters — the inserts arranged in radiatively trans- parent media (for tube convective type recupera- tors) or within flow of emitting combustion prod- ucts moving along flue gases channels (for basket type radiatiative recuperators). Application of the inserts within the channels in media of both types serves to provide enhancement of heat flux by radiatiation from the heat exchange surface be- tween two media and to increase area of reception surface to transfer the resulting heat flux absorbed by flow to be preheated by convection. Radiative heat transfer provides the main component in the heat flux to reception surfaces from the side of combustion products. The channel for combustion products flow in the radiative re- cuperators has considerable size by the whole length (height) of heat exchange (reception) sur- face. Radiative recuperators have a wide spread in the furnaces of various purpose where combustion products temperature makes 1300–1700 K at the inlet to recuperator or at furnace exit [3, 4]. By this reason the great demands are made of ther- mal stability of metallic heat exchange surfaces in recuperators, the counter — flow scheme being used in case of inlet gases temperature of 1270–1470 K while by flue gases temperature over 1470 K — the co-flow scheme. Radiative slot recuperators represent as a rule two coaxial casings where the combustion products are flowing within the inner housing while an air flow is moving through the annular slot [2]. The casings are made of steel sheet of 5–10 mm thickness, inner diameter of the central casing makes 0.5–3.5 m — in dependence on recuperator output and the air slot width makes 8–60 mm. There is an opportunity to manufac- ture the recuperators by layout of one-sided (Fig. 1, a) and double-sided heating (Fig. 1, b). In both cases the relatively insufficient area of heating (heat exchange) surface makes short- coming of the recuperators design because air flow is heated only within the single annular slot channel while working space of transportation the flue gases flow is used wasteful. Heat ex- change sheet partition between «hot» and «cold» flows is insufficient by its area. It has been proposed to use the secondary emitters in form of radial partitions to enhance heat exchange within flue channel of the slot re- cuperators [5]. These facilities increase the heat flux by radiation to inner shell and thus are en- hancing the heat efficiency of recuperator. The original design of radiative two-passage recuperator of RRD type (see Fig. 2) has been developed in Gas Institute of National Academy of Sciences of Ukraine [6]. The relevant design is characterized by rational mutual arrangement the heating surfaces as well as by secondary emitters installation within the flue channels. By means of improvement the recuperator design we were succeeded in combustion air preheating tempera- ture Ta,ex enhancement and in increase of heat flux transferred to air flow as the secondary heat- transfer medium. High efficiency of RRD type recuperator under consideration is provided due two-stage air preheat. Ýíåðãîòåõíîëîãèè è ðåñóðñîñáåðåæåíèå. 2014. ¹ 3 57 Fig. 1. Radiative slot recuperator: a — with one-sided heat- ing; b — with double-sided heating. The 1st heating stage is performed within inner an- nular channel by two coaxial shells with dou- ble-sided heating from combustion products. The last flow is directed from the furnace exhaust up- wards to the recuperator inlet and than is divided by two combustion products flow: central cylindri- cal and peripheral annular one. The 2nd heating stage represents the peripheral annular channel filled in with moving downwards air flow. The channel is surrounded from inner side with the steel shell been flowed over with the peripheral flue gases flow (of combustion products). The ther- mal insulation is formed by coating upon the exter- nal side of the outer casing of peripheral air flow. Both air channels of co-flow (parallel (-current)), and counter current flows are connected by the sys- tem of radial tubes above the recuperator top. Due enhancement the heat exchange process the final temperature of media to be preheated is increasing while the heat exchange surface tem- perature is decreasing and thus the service life of the facility on the whole should be prolonged. 1.2. Stages and matter of experimental tests. The advantages of new equipment by us- ing the process gases, biogases and the gasifica- tion products of industrial wastes, solid and liq- uid biofuels for firing purposes need of special confirmation. The recuperator design ensures an enhancement of heat transfer providing lower level of temperature of heat exchange surfaces and thus reducing the corrosion effect by action of gas flows. It makes possible the efficient utili- zation the heat content of LCV flue gases in wide range of technologies. An increase of efficiency of application of blast furnace gas (BFG) and coke oven gas (COG) as well as of the mixture of BFG and COG for high temperature processes and technologies is of great importance. Because of similar reasons the application of an new heat recovery appliances is also advanta- geous by gasification technologies. The produc- tion and application of gaseous products from carbon based or other solid organic fuels by par- tial oxidation of the mentioned materials is one of main targets of the power engineering for the next decades. These technologies are providing the engineering basis of the CO2 free «clean-car- bon» programs. The heat exchanger to be devel- oped in framework of the present project provides more safe and economic operation of the facility. The tests of heat exchanger operating with LCV gases of corrosive flue and, if is it re- quired, the steps for further development have to be made. In the framework of the EUREKA project Co. TUKI�� will undertake performing of this part of the task. The Supporting Contract (EUREKA HU 12–1–2012–003) has appeared due approval by the International Development Agency concluded with the Co. MAG. Starting of the program be- gan in February 2013. Co TUKI�� is intending to realize its investiga- tion program through two directions. In the first phase the recuperator to be tested will be in- stalled at bell-type furnace operating with mix- ture of blast furnace gas (BFG) and coke oven gas (COG). The tests will be carried out under real working conditions. By means of these stud- ies will be get appropriate data regarding the op- eration features of the facilities. In the second phase of these trials the recuperator will be installed at the special experi- mental furnace of 200 kW capacity. The furnace will be fired with the blast furnace gas and coke oven gas as well as with the combination of two fuels of various composition. A database on the temperature and pressure losses and further mea- suring variables will be recorded jointly with the Ukrainian partner on the temperature and pres- sure losses and further measuring variables. For LCV gases the determination of the optimal de- sign has to taken into account the heat transfer factor, the minimal heat exchange surface tem- perature, the smallest pressure losses and minimal danger of deposition. 58 Ýíåðãîòåõíîëîãèè è ðåñóðñîñáåðåæåíèå. 2014. ¹ 3 Fig. 2. Radiative recuperator of RRD type design developed by Gas Institute of NASU [2]. Combustion products flow is shown by thick lines, air flow — by plane (thin) lines. The great complex of modelling researches, numerical analysis and the experimental tests car- ried out with the tube convective recuperator sec- tions arranged at the large — scale firing rig along with the proper validation data have con- firmed convincely the justice and adequacy of initial statements used by development the novel approach to designing the high temperature recu- perators [7]. It must be stated that till present all tests with application of the recuperators of new de- signs have been carried out exclusively by firing the furnace (furnace chamber) with natural gas. 1.3. The trial furnace with RRD type recuperator. For the purpose of the trials with LCV gases the RRD type radiative-convective recuperator [patent] developed by the Gas Insti- tute will be used. The chosen type can be ex- plained by the related market demands. The high temperature is characterizing the majority of the utilized technologies and they require involving the possibilities of the radiation heat transfer [8]. Naturally, the convection is also an important part of the combined heat transfer and the in- crease of its intensity is of great importance espe- cially within temperature range inherent for heat treatment furnaces. In the first phase of the investigations the recuperator will be installed at the bell-type fur- nace of the Cold Rolling Mill Ltd. of the Co. ISD DUNAFERR [9]. This furnace set is consisted of thirty sockets and by twenty four of these ones the TUKI�� ap- plied 2–2 pieces of bag basket type recuperators at each furnace for combustion air preheating. The furnaces are fuelled with blast furnace gas and coke-oven gas in ratio of 4 : 1, providing BFG and COG mixture of average heating value of 5.6–6 MJ/m3. The furnaces are of batch-type operation. Temperature of the flue gas in the second part of the up heating phase resp. during the soaking pe- riod is in the range of 800–900 �C. The Volume flow rate of an air to be preheated in recuperator is about 600 m3/h. The gas mixture is burned by means of 6 Pyronics HS7 type burners installed on the mantle of the heating bells [7]. The flue gases flowing by side of the internal protective bell transfer a certain part of its heat content and leave the heating bell through its upper section. The Fig. 3 shows the heating bell equipped with the recuperators of RRD type. Their loca- tion is identical to the present arrangement of exsting heat recovery plants. The recuperators of perpendicular axis are located on the outer man- tle of the bell. The flue gases leaving the furnace gets to the recuperator through the baffle element of 90� and the compensator. An air operated ejec- tor located along the centre ensures the appropri- ate effect of sucking. After its blending with the flue gases, the mixture leaves the facility at the bottom and flows to the flue gases channel. By operation of new design of developed recuperator of RRD type (Fig. 2 and Fig. 4) the flue gases are flowing in two parallel pathways: within central internal channel and through in- termediate peripheral annular space. The direc- tion of moving flows along the axis from the recuperator top to the bottom. The air is flowing through recuperator in two lines connected in turn. In the first one a parallel flow heat transfer is realized by heating of the air channel from both sides. After turning the air is flowing in contrary direction. Within the outer air channel a counter flow heat transfer takes place. The outer mantel is furnished with heat insulation. It has been foreseen to keep the existing flue gases and air connections of the recuperator by designing the RRD type recuperator for arrangement at the bell type furnace for testing to be carried out. To increase an efficiency of heat exchange between primary (combustion products) and se- condary (an air flow) heat transfer media within the central flue gases channel the radial ribs been crossed between themselves, is arranged. The auxiliary emitters made of plane radial ribs are installed within the combustion products annular channel. Mentioned indices are ensuring increase of total heat flux to the walls of recuperator channels. Ýíåðãîòåõíîëîãèè è ðåñóðñîñáåðåæåíèå. 2014. ¹ 3 59 Fig. 3. Coil annealing bell-type furnace with installed recu- perators. 2. Development of technique with differen- tial equations for comparative calculations The RRD type recuperator represents the novel developed modification of the wide spread heat utilizing equipment. Comparing with the «traditional» chimney recuperators, they have about the double length of pathways for the air and roughly three times bigger heat transfer sur- faces. In order to define the surplus of the waste utilization, calculation model was developed in frame of EUREKA project basing on simple dif- ferential approach to heat exchange evaluation between flows separated by cylindrical shells. The model concerns of both RRD and «tube in tube» recuperators designs. The last one (BR) was chosen as basic equipment for comparison the characteristics under consideration. Fig. 5 shows the calculation sketches and introduces the no- menclature of main parameters. Initial values have been introduced below for generalization the obtained calculations results as follows. The scale of the air flow preheating can be expressed by the ratio �T = (Tair,out – Tair,0)/ /(Tfg,0 – Tair,0) = (Tair,out/Tfg,0) � � [(1 – Tair,0/Tair,out)/(1 – Tair,0/Tfg,0). (1) The quotient of enthalpies (physical heat contents) characterising the degree of heat utili- zation: �q = (cair �Vair Tair out)/(cfg �Vfg Tfg,0). (2) The channels design accord- ingly models don’t include nei- ther primary flow directing nor swirl inducing elements. 2.1. Basic correlations. Bernoully’s equation for flue gases flows and for air flow as well indicates conservation of the mechanical energy value. The matter is that the flow movement process within the central and annular flue gases channels takes place simulta- neously with heat transfer pro- cess. As a result the energy conservation differential equa- tion corresponding to the 1st thermodynamics law has the following form 60 Ýíåðãîòåõíîëîãèè è ðåñóðñîñáåðåæåíèå. 2014. ¹ 3 Fig. 5. Calculation layout for the models under consideration: A1, A2, A3 — heat ex- change surfaces between primary (combustion products and secondary (air flow) heat transfer media; k1, k2, k3 — heat exchange coefficients for respective heat exchange surfaces. Fig. 4. Design layout of new type of experimental recuperator for the bell-type furnace. dq =du + p dv + d (w / 2) dq =di – v dp + d (w / 2) dq =c d 2 2 p T – dp / + d (w / 2)2� � � . (3) The last equation in the system (3) represents differential form of the equation for «total energy e» [10] (in case under consideration — for non-re- acting flow). It means that supplied heat is mainly con- sumed for flow preheating and acceleration (change the velocity (dynamic) head or kinetic head). As a result the pressure losses are greatly increased in comparison with isothermal (low- temperature) flow. Simultaneously a portion of in- ternal energy dqdiss is dissipated because of sub- stantial growth of hydraulic resistance by flow movement. In above given equations the following nomenclature is used: q — supplied heat amount; internal energy; i — enthalpy; w — flow velocity; T, p, �, v — temperature, static pressure, gas (air) density and specific volume at given p and T con- ditions, cp — specific heat content. Moreover, account of the pressure losses with friction (only) is insufficient because of more strong impact of temperature on other accompany- ing constituents, first of all on local pressure losses: those division the flue gases flow before its entering into the flue channels, by inlet to and outlet of the pathways. �Q = cpm �T – �p/�m + 0.5 �w2 + (i) � i w 2 (4) or the transferred heat flux Qa between 1 and 2 cross sections along the pathway or the considered flow and channel, �Q = cpm (T2 – T1) + (p1 – p2)/�m + + 0.5 (w2 2 – w1 2) + (i) � fr i w 2 + (j) � loc j w2. (5) In equations (4) and (5) the subscript «m» means averaged value within temperature range while «i» and «j» are referred to friction and local resistances by pathway between mentioned arbi- trary chosen cross-sections 1 and 2. The averaged values of heat capacity (specific heats at constant pressure) of the heat exchanging media are used. 2.1.1. Parallel flow. The relation of the temperatures change within the parallel flow could be found basing upon the heat balance equation from initial to current cross-section of the channel: Tair = Tair,0 + � (Tfg,0 – Tfg), (6) where factor � has been the «water value quotient» modified by the efficiency of the heat exchanger: � = � (cfg �Vfg)/(cair �Vair). (7) Total heat flux transferred to the air volume flow rate �Vair as function of local temperatures of heat transfer media can be expressed by the dif- ferential equation: d�Qair = cair �Vair dTair = ki di � (Tfg – Tair) dx. (8) Substituting the temperature of the flue gas from equation (6) by means of integration proce- dure, we obtain the solution in form of exponen- tial equation for current location (cross-section x along the tube pathway): T T T T T kd x c air fg,0 air,0 fg,0 air,0 ai � � � � [ – ( – ) exp (– � 1� r airV� )] / ( .� � � 1 1 � � �� (9) By using the simplified indicator � = (k Fi)/(cair �Vair) (10) the temperature of preheated air at the recu- perator exit of length «L» could be obtained in following form T T T T T air,out fg,0 air,0 fg,0 air,0 � � � � [ – ( – – ) exp (– � � � 1 � � ��)] / ( .1� (11) The air preheating ratio at this stage of heat exchange makes parallel� �� � �� � � �[ – exp (– )] / ( ).1 1 1 ���� 2.1.2. Counter flow. Comparing with equation (6) the temperature relation regarding heat exchange media in case under consideration will be changed. Temperature pattern will be pre- sented for the pathway site from current till exit cross-section: Tair = Tair,0 + � (Tfg – Tfg, out). (13) Similarly, the temperature of air at the tube exit is somewhat different from the same by par- allel flow T T Tair,out air,0 fg,0� � � � ( – [ – exp (– – )] / [ – 1 1 1 1 �� � � � �� exp (– – )]� 1 � � (14) where the definition of the parameter «�» is un- changed. The following expression demonstrates the recuperator’s opportunity for the second stage of air preheating �counter = � {1 – exp [–� (1 – �)/�]}/ /(1 – � exp [–� (1 – �)/�]. (15) Ýíåðãîòåõíîëîãèè è ðåñóðñîñáåðåæåíèå. 2014. ¹ 3 61 The equations 12 and 15 show that efficiency of the heat exchanger has been defined by parame- ters «�» and «�». In order to get their real influ- ence, we’ve carried out some evaluative calcula- tions. They are based upon characteristics given in Fig. 6 while operation parameters of the bell type furnace should be taken into account as well. It has been stated that the calculated air tem- perature is practically independent on flow direc- tion. The difference at the investigated combina- tions of parameters didn’t exceed the value of 4 �C. Fig. 7 introduces the effect of parameter «�» being proportional to the heat exchange coeffi- cient «k». Independently from the value «�» the function under consideration is nearly linear — harmonising with equations (6) and (13). The ef- fect of parameter «�» could be seen in the Fig. 7. Its influence is minimal. At higher «�» values (higher heat exchange coefficient) differ- ence of Tair,out values becomes slightly increas- ing, but even doubling of the flue gases volume flow rate results only in about 15 �C growing of exit temperature. Within the RRD recuperator the surfaces A1 and A2 are serving for heat exchange process be- ing realized in parallel flow. Through A3 surface the second stage of heat exchange performing and of air preheating takes place in counter flow. Therefore the heat balance equations of the flow- ing media are as follows (see Fig. 5, directions of heat balance consideration — along the axis of the system, upwards from the recuperator’s enter cross-section): — for the «primary» flue gases within the internal tube –cfg �Vfg,l dTfg,1 = k1 d1 � � � (Tfg,1 – Tair,1) dx.1/�; (16) — for the inner annular pathway — first line of air (parallel flow) cair �Vair dTair,1 = – cfg �Vfg,l dTfg,1 + + k2 d2 � (Tfg,2 – Tair,1) dx. (17) The heat balance of the outer flue gases flow the «second» line could be presented in differen- tial form –cfg �Vfg,2 dTfg,2 = – cair �Vair dTair,2 + + k2 d2 � (Tfg,2 – Tair,1) dx, (18) while the same for outer pathway — second line of air (counter flow) — will be expressed by equation –cair �Vair dTair,2 + k3 d3 � � � (Tfg,2 – Tair,2) dx. (19) The system of equations can’t be solved by direct formulas. It requires an application of nu- merical technique. In order to simplify the calcu- lation, it was considered, that comparison re- quires the exit temperatures only. Applying the defining values — mean logarithmic temperature differences — the system of the differential equa- tions (16)–(19) could be substituted by the final equations (20)–(24). The numbers in the lower indexes are related to the pathway (lines, trajec- tories) of the flue gases regarding to the heat transfer surfaces. The system has to be solved by iterations technique. As the first step it is expedient to esti- mate temperature Tair,m. As its initial value we’ve used the exit air temperature of BR recuperator (see equation (11) for exit air pre- heating temperature by co-flow (parallel-current flow) heat exchange case) multiplied by the ratio of heat transfer surfaces (see equation 24). 62 Ýíåðãîòåõíîëîãèè è ðåñóðñîñáåðåæåíèå. 2014. ¹ 3 Fig. 6. The effect of parameter «�» on the outlet temperature of preheated air. Fig. 7. The effect of parameter «�» on the outlet temperature of preheated air. The last mentioned value meets to ratio of total heat exchange surface for recuperator of RRD type to that of single surface («i») for recuperator of BR type. It must be taken into account that ratio of surfaces in equation (24) as a first approximation meets to ratio of total heat fluxes transferred in recuperators RRD and BR. The last exceeds the real ratio of intermediate temperature Tair,m in RRD recuperator to Tair,out in BRparallel. The computation equations do not account the possible effect of alteration the transfer pro- cesses by each side of heat exchange surface in- fluencing on convective and radiative constitu- ents like the increased turbulence, difference of coefficients k1 and k2, and the modified tempera- ture differences between the media. They com- pensate partly one another, hence is it acceptable as initial condition. The calculation with the equations (20), (21) and (23) results the value of Tfg,1,out, Tfg,2,out and Tair,out. The preliminary date of Tair,m by equa- tion (24) can be checked and corrected by equa- tion (22). The input parameters for the comparative calculation are summarized in the Table 1. The same values of heat exchange coefficients ki for each of heat exchange surfaces have been supposed. The calculations have been carried out with two values of ki = k: 10 and 20 W/(m2.K) (see Table 2). The data of the Table 2 show, that at k = 10 W/(m2.K) the exit temperature of air pre- heating by application of RRD type recuperator has been more than doubled in comparison with ordinary type plant. By case of k = 20 W/(m2.K) the exit air temperature will be 90 % higher for RRD recuperator the respective tem- perature for ordinary recuperators of BR type. The heat exchange coefficient «k» depends on the heat transfer coefficients from both sides according to the well known equation [10]: k–1 = �fg –1 + �air –1. (25) Ýíåðãîòåõíîëîãèè è ðåñóðñîñáåðåæåíèå. 2014. ¹ 3 63 Table 1. The input data of the models Characteristic �Vair �Vfg �Vfg,l �Vfg,2 di de d1 d2 d3 d4 L Tair,0 Tfg,0 � Dimension m3/s m3/s m3/s m3/s m m m m m m m K K – Value 0,11 0,17 0,1 0,07 0,43 0,48 0,35 0,41 0,55 0,61 1,5 293 1273 0,9 Table 2. Comparison of characteristics of standard of recuperators BR with the developed one of RRD type Type of recuperator k Tair,out Tair,m Tfg1,out Tfg2,out �t �q W/(m2.K) K (�C) K (�C) K (�C) K (�C) – – BRparallel 10 417 (144) – 1191 (918) – 0,126 0,081 BRcounter 10 418 (145) – 1190 (917) – 0,128 0,082 RRD 10 589 (316) 483 (210) 1172 (899) 982 (709) 0,302 0,170 BRparallel 20 516 (243) – 1125 (852) – 0,227 0,137 BRcounter 20 520 (247) – 1123 (850) – 0,231 0,139 RRD 20 740 (467) 603 (330) 1100 (827) 864 (591) 0,456 0,263 Generally, the velocity of flue gases is lim- ited and it determines the intensity of the whole heat exhange process for the furnaces of moderate level of working temperatures. The RRD type recuperator is supplied with additional internal emitters (inserts) in order to improve the heat transfer coefficient at the flue gases side. In spite of limiting impact of heat transfer at the air side of heat exchage surfaces (�air < �fg) the effect of hot side is growing with insreasing the flue gases temperature due increase the temperature head Tfg – Tair. More adequate and reliable data will be defined in the process of trials at the bell type furnace. The effect of «k» factor by BR recuperator application is somewhat more intensive. Its dou- ble value results in about 80 % higher gain of an air preheating exit temperatures (see Table 2) while in case of RRD type heat exchanger the same change of heat ex change coefficients (k = 20 against 10 W/(m2.K) causes only 50 % gain of Tair,out – Tair,0. This difference for RRD is bigger than the same for BR by absolute value. Determination of the actual «k» factors re- quires an accurate calculation of convective and radiative heat transfer coefficients from both sides. Obviously, these values will be different for each heat exchange surfaces. The range of value «�» makes about 0.9 by natural gas combustion. While in case of LCV gases using it could be of significantly varied value. For example by blast furnace gas applica- tion it makes more than � = 2.0. However, as could be seen from the Fig. 6, the exit air tem- perature is slightly influenced by � value. 3. Numerical analysis of thermal characteristics for RRD type recuperator by alteration the geometry of heat exchanger In Fig. 8 the impact of extension the heat the heat exchange surface (the relative area ~ F) upon an temperature of air preheating Ta,ex = Tair,out within the recuperator of bell-type fur- nace is shown in curve 1 [8]. In the last work the recuperator design doesn’t presented. The modern bell-type annealing furnaces are equipped with high-efficient individual recuperators for each of burners or with centralized recuperator. The pro- cess under consideration is related to the number of low — and of middle-temperature thermal treatment process (840–880 K) [11]. Meanwhile taking into account the variety of the annealing processes for steel ingots (bright and dark, spheroidizing, prehydrogen firing etc.) as well as of other firing process the range of working tem- peratures up to 1400 K. Maximum are preheating temperature for recuperators of bell-type furnaces makes 730 K, an average air preheat temperature by annealing process makes 630 K or a little-bit lower. In these conditions power loss with flue gases behind recuperator constitutes up to 28 % [8]. Further increase air of preheating tempera- ture till 900 K provides additional reduction of natural gas flow rate by 11 % in the technology under consideration however demands a signifi- cant enhancement of recuperators heat exchange surface [8]. The results obtained in paper [8] are com- pared with our data. The Òa,ex temperatures ac- cordingly our computations are marked as the dots and joined by respective curves (Fig. 8) in dependence on ~ F value influence. The correlations between ~ F value and exit air temperature Òa,ex for radiative recuperators of new original design of (RRD type — radiative recuperators of dou- ble-passage) [6] (Fig.2). The following conditions of recuperator’s ef- ficiency comparison by variation of heat exchange surface ~ F in new design were tested: increase of recuperator’s height or/and of diameters of shells. The criterium of heat exchange surface change ~ F = � (D2 + D3 + D4) H/F0, where Di and H — respectively the recuperators height and diameters of shells; F0 — area of basic (of one-sided) design heat exchange surface. 64 Ýíåðãîòåõíîëîãèè è ðåñóðñîñáåðåæåíèå. 2014. ¹ 3 Fig. 8. Dependence of combustion air preheating temperature Ta,ex, Ê, on relative value of recuperative heat exchange sur- face ~ F, %: 1 — curve by data of paper [8]; 2 — the dots ac- cordingly our computations for radiative recuperator of RRD type by increase of heat exchange surface due to rise the recu- perators height H; 3 — accordingly our computations for radi- ative recuperator of RRD type (Fig. 2) by effect upon heat ex- change surface by means of change the diameters of heat ex- change surfaces; 4 — accordingly our computations for radia- tive recuperators with one-sided heating by effect on the sur- face due to change the recuperator height H. Ratio of diameters was supported as invariable (constant) value by variation the heat exchange surface: D4/D3 = const, D4 /D2 = const, D1 — diameters of heat exchange surfaces (see Fig. 2). In the Fig. 8, curve 4 the computation dots are marked as well for radiative recuperator of traditional design likely the slot design heat exchanger with one sided heating (see Fig. 1, a). The recuperator’s design is distinguished with parallel (current) flow of combustion products and air flow to be preheated [2]. As could be seen from the Fig. 8 the high efficient RRD type recuperators proposed by our team provides an opportunity for great increase an air preheating temperature (up to two times — in �C) in com- parison with traditional design of radiative recu- perators with one-sided heating. The following initial data have been chosen for calculation the basic version of radiative recu- perators of RRD type by evaluation the dimen- sions influence ( ~ F = 100 %): inner diameter of outer shell D1 = 1.3 m, the diameters of annular channels: for air flow delivering D2 = 1.24 m, for flue gases removal D3 = 0.87 m. Inner diameter of central flue gases channel D4 = 0.8 m. Width � of air slot channels is equal to 0.025 m. The recupera- tors height makes H = 3 m. Combustion products temperature at the re- cuperators inlet makes Tf,en = 1173 K; for air flow inlet Ta,en = 298 Ê. Mass air and combus- tion products flow rates make respectively: �ma = 0.786 kg/s; �mfl = 0.825 kg/s. For basic design of radiative recuperator with one-sided heating the similar sizes with RRD type recuperators have been taken: diameter of outer shell D1 = 1.3 m; recuperator height Í = = 3 m. Width of air flow makes � = 0.025 m. Mass air and flue gases flows as well as initial temperatures of the flows performing heat ex- change process were taken of the same values as assumed above for calculation the RRD type re- cuperators. Conclusion 1. Creation of highly efficient recuperators of advanced design has been envisaged in frame of performing the joint European project accord- ingly EUREKA program. The final purpose of mentioned development makes provision the con- ditions of high temperature operation of the in- dustrial furnaces by replacement the hydrocar- bons for alternative fuels. These heat exchangers are intended for preheating both the combustion air and/or low-calorific gas fuels. 2. The radiative recuperator of basket type has been chosen for further improvement as uni- versal and of low hydraulic resistance design for the furnaces of periodic and continuous opera- tion. For enhancement the power efficiency of recuperator and to increase the transferred result- ing heat fluxes the following approaches have been sdudied: increase of heat transfer surface and rise of heat transfer coefficient due affect of intermediate (secondary) emitters arranged within the heat transfer channels for mediums, firstly — for flue gases. 3. The paper presents a simplified calculation technique for prediction the heat transfer process in the basket-type recuperator of new design. This approach has been proposed for analyzing of coaxial-flow system of heat transfer media move- ment. The results of the calculation have proved, that almost twice increase of air preheat tempera- ture can be achieved by enhancing of the heat ex- change surface in new recuperator design. En- hancement of coefficient «k» by application of internal secondary emitters was not considered. The effect of combined account of both factors of increase of an air preheat under application of RRD type recuperator: enhancement of coeffi- cient «k» and of growth of heat exchange surface — influence was predicted by numerical calcula- tions and would be defined through the trials of recuperators installed at industrial furnaces. 4. Recuperator of RRD type provides an in- crease of combustion air preheat temperature Ta,ex in comparison with slot type radiative recuperator. Both balance calculation techniques: differential and averaged engineering approaches show the similar impact of increase the heat ex- change surface on increment of Ta,ex value in comparison with traditional heat exchangers. For RRD recuperators under consideration the value of mentioned air preheating temperature increase can exceed 200 �C. References 1. Soroka B., Vorobyov N., Zgursky V., Karabchiev- skaya R. Advanced Heat Recovery Equipment For High Temperature Combustion Plants. The Fif- teenth International Symposium «Materials, Meth- ods & Technologies», Sunny Beach Resort, Bulgaria, 10–14 June, 2013. Sunny Beach Resort, 2013, pp. 69–83. 2. Tebenkow B.P. Recuperators for industrial furnaces. Moscow : Metallurgia, 1975, 296 p. (Rus.) 3. Pioro L.S., Pioro I.L., Kostyuk T.O., Soroka B.S. Industrial Application of Submerged Combustion Melters. Kiev : Fact, 2006, 240 p. (USA copyright). 4. Oyelami A.T. Performance Evaluation of Recupera- tive Heat Exchanger in Rotary Furnace. Proceedings of the World Congress on Engineering 2012 WCE, London, U.K., 4–6 July, 2012, 7 pp. Ýíåðãîòåõíîëîãèè è ðåñóðñîñáåðåæåíèå. 2014. ¹ 3 65 5. Kardas A., Larson D., Nesbitt J., US Patent 3886976, 1975. 6. Soroka B.S, Sandor P., Vorobyov N.V. Radiative recuperator, Ukraine patent for invention ¹ 103961, 2013. 7. Sevcsik M., Kapros T. [A Utilization of NC gases at combustion technology]. Metallurgy, 2008, (12). (HU) 8. Wendt P., Kuehn F. Modernization and efficiency of thermal processing. Heat Processing, 2011, (9), iss. 1, pp. 21–28. 9. [Adaptation of the bell type furnaces of the Cold Rolling Mill of ISD DUNAFERR for natural gas fining]. TUKI�� study April of 2013).(HU) 10. Bendersky B.Ya. Engineering thermodynamics and heat transfer. Moscow; Izhevsk, 2002, 264 p. 11. Mishin M.P., Sarychev A.F., Lebedev S.A. Method of annealing rolls in bell furnace. Russian Federation Patent ¹ 215104, 1999. Received 21 August, 2014 66 Ýíåðãîòåõíîëîãèè è ðåñóðñîñáåðåæåíèå. 2014. ¹ 3 Øåâ÷èê Ì.1, äîêò.òåõí. íàóê, Êàïðîø Ò.1, êàíä. òåõí. íàóê, Øàíäîð Ï.2 äîêò. òåõí. íàóê, Ñîðîêà Á.Ñ.3, äîêò. òåõí. íàóê, ïðîô. 1 Ïðîåêòíî-èññëåäîâàòåëüñêèé èíñòèòóò òîïî÷íîé òåõíèêè «ÒÞÊÈ», Ìèøêîëüö, Âåíãðèÿ 3515, Miskolc-Egyetemvaros, Pf.3, Hungary, e-mail: project@tuki.hu 2 «Îïòèìóì ýíåðãî-ýêîëîãèÿ ËÒÄ», Ðàöàëìàø, Âåíãðèÿ Martinasz u.1,2459, e-mail:sandordr@vnet.hu 3 Èíñòèòóò ãàçà ÍÀÍÓ, Êèåâ, Óêðàèíà óë. Äåãòÿðåâñêàÿ, 39, 03113 Êèåâ, Óêðàèíà, e-mail: b.soroka@gmail.com Ðàçðàáîòêà ìåòîäèêè ðàñ÷åòà ñ öåëüþ ñîçäàíèÿ âûñîêîýôôåêòèâíîãî ðàäèàöèîííîãî ðåêóïåðàòîðà â ðàìêàõ âûïîëíåíèÿ ïðîãðàììû «EUREKA» Ïðîåêò «REPLACE NG» («Çàìåùåíèå ïðèðîäíîãî ãàçà») íàïðàâëåí íà ðàçðàáîòêó è èñïîëüçîâàíèå ðàäèàöèîííîãî (ðàäèàöèííî-êîíâåêòèâíîãî) ðåêóïåðàòîðà íîâåéøåé êîíñòðóêöèè äëÿ óòèëèçàöèè òåïëîòû óõîäÿùèõ ãàçîâ ïðè ñæèãàíèè òîïëèâ, âêëþ÷àÿ íèçêîêàëîðèéíûå (LCV) ãàçû, â ïðîìûøëåííûõ ïå÷àõ ðàçëè÷íîãî íàçíà÷åíèÿ.  ñîîòâåòñòâèè ñ ïëàíîì ðàáîò ïðåäïîëàãàëîñü, ÷òî ðàçðàáàòûâàåìûå ðåêóïåðàòîðû äîëæíû áûòü ïðèãîäíû äëÿ íàãðåâà âîçäóõà ãîðåíèÿ è ñàìèõ íèçêî êàëîðèéíûõ ãàçîâ. Ðåêóïåðàòîðû äâîéíîãî íàçíà÷åíèÿ ìîãóò èñïîëüçîâàòüñÿ ïðè óñòàíîâêå íà ïå÷àõ, îòàïëèâàåìûõ íèçêîêàëîðèéíûì ãàçîì. Óïîìÿíóòîå îáîðóäîâàíèå — ðåêóïåðàòîð òèïà ÐÐÄ — ðàçðàáîòàíî Èíñòèòóòîì ãàçà ÍÀÍÓ (Óêðàèíà).  ñîîòâåòñòâèè ñ ïðåäâàðèòåëüíîé ïðîãðàììîé è ãðàôèêîì ðàáîò áûëî íàìå÷åíî ïðèâëå÷åíèå êîìïàíèè «ÒÞÊÈ» (Âåíãðèÿ) â êà÷åñòâå ïàðòíåðà ïî ïðîåêòó íà ðàçíûõ ýòàïàõ, â ÷àñòíîñòè, ïðè èñïûòàíèÿõ ðåêóïåðàòîðà, ìîíòèðóåìîãî ñ ýòîé öåëüþ íà êîëïàêîâîé ïå÷è â öåõå õîëîäíîé ïðîêàòêè êîìáèíàòà «ÈÑÄ ÄÓÍÀÔÅÐл.  õîäå èñïûòàíèé ïðåäóñìîòðåíî îïðîáîâàòü îòîïëåíèå ïå÷è ðàçëè÷íûìè òåõíîëîãè÷åñêèìè ãàçàìè ìåòàëëóðãè÷åñêèõ ïðîèçâîäñòâ (àëüòåðíàòèâíûì òîïëèâîì).  íàñòîÿùåé ðàáîòå ïðåäñòàâëåí âûâîä ðàñ÷åòíûõ çàâèñèìîñòåé, îáåñïå÷èâàþùèõ ïðÿìîå ñðàâíåíèå òåïëîâîãî ñîñòîÿíèÿ òåïëîîáìåííèêà íîâîãî òèïà è ðàäèàöèîííûõ ðåêóïåðàòîðîâ òðàäèöèîííîé øèðîêî ðàñïðîñòðàíåííîé êîíñòðóêöèè. Ìåòîäèêà áàçèðóåòñÿ íà ðàñ÷åòå ïðîöåññîâ òåïëîîáìåíà â óñëîâèÿõ ïðÿìî- è ïðîòèâîòî÷íîãî âçàèìíîãî äâèæåíèÿ òåïëîíîñèòåëåé â êàíàëàõ. Óïðîùåííûå äèôôåðåíöèàëüíûå óðàâíåíèÿ òåïëîâîãî áàëàíñà è òåïëîîáìåíà äëÿ ðàçíûõ ó÷àñòêîâ ðåêóïåðàòîðà áûëè èñïîëüçîâàíû â êà÷åñòâå áàçîâîé ñèñòåìû ïðè ïîëó÷åíèè ðàñ÷åòíûõ çàâèñèìîñòåé. Áëàãîäàðÿ îòûñêàíèþ è ïðèìåíåíèþ îáîáùàþùèõ âñïîìîãàòåëüíûõ áåçðàçìåðíûõ ïàðàìåòðîâ ðàñ÷åòíàÿ ìîäåëü îáåñïå÷èâàåò âîçìîæíîñòü àíàëèçà âëèÿíèÿ êîýôôèöèåíòîâ òåïëîîáìåíà, ìàññîâîãî è îáúåìíîãî ïîòîêîâ òåïëîíîñèòåëåé è òåïëîâûõ ïîòîêîâ íà ðåçóëüòèðóþùåå òåìïåðàòóðíîå ðàñïðåäåëåíèå â Ýíåðãîòåõíîëîãèè è ðåñóðñîñáåðåæåíèå. 2014. ¹ 3 67 àïïàðàòå â ïðîöåññå ïîäîãðåâà âîçäóõà. Ïðåèìóùåñòâà íîâîãî ïîäõîäà ê ïðîåê- òèðîâàíèþ ðåêóïåðàòîðîâ äàæå â ñëó÷àå ïðåíåáðåæåíèÿ ðîñòîì èíòåíñèâíîñòè òåïëîîáìåíà ñ îáåèõ ñòîðîí òåïëîîáìåííîé ïîâåðõíîñòè îáúÿñíÿþòñÿ ñóùåñòâåííûì óâåëè÷åíèåì îáëàñòè òåïëîîáìåíà (â ñëó÷àå ðåêóïåðàòîðà òèïà ÐÐÄ) ïî ñðàâíåíèþ ñ îáû÷íûìè îäíîõîäîâûìè ðàäèàöèîííûìè ðåêóïåðàòîðàìè. Èñïîëüçîâàíèå âòîðè÷- íûõ (ïðîìåæóòî÷íûõ) àäèàáàòíûõ èçëó÷àòåëåé â êàíàëàõ äëÿ äûìîâûõ ãàçîâ è âîçäóõà (èëè ïîòîêîâ íèçêîêàëîðèéíîãî ãàçà) îáåñïå÷èâàåò äîïîëíèòåëüíûå âîçìîæíîñòè ïîâûøåíèÿ ïîäîãðåâà âîçäóõà (èëè íèçêîêàëîðèéíîãî ãàçà). Áèáë. 11, ðèñ. 8, òàáë. 2. Êëþ÷åâûå ñëîâà: âîçäóõ ãîðåíèÿ, êîëïàêîâàÿ ïå÷ü, êîýôôèöèåíò òåïëîîòäà÷è, êîýôôèöèåíò òåïëîïåðåäà÷è, íèçêîêàëîðèéíîå òîïëèâî, ïðîòèâîòîê, ïðÿìîòîê, ïðîäóêòû ñãîðàíèÿ, ðàäèàöèîííûé ðåêóïåðàòîð, òåìïåðàòóðà òåïëîíîñèòåëÿ, òåïëîâîé ïîòîê. Øåâ÷èê Ì.1, äîêò. òåõí. íàóê, Êàïðîø Ò.1, êàíä. òåõí. íàóê, Øàíäîð Ï.2, äîêò. òåõí. íàóê, Ñîðîêà Á.Ñ.3, äîêò. òåõí. íàóê, ïðîô. 1 Ïðîåêòíî-äîñë³äíèé ³íñòèòóò òîïêîâî¿ òåõí³êè «ÒÞʲ», ̳øêîëüö, Óãîðùèíà 3515, Miskolc-Egyetemvaros, Pf.3, Hungary, e-mail: project@tuki.hu 2 «Îïò³ìóì åíåðãî-åêîëîã³ÿ ËÒÄ», Ðàöàëìàø, Óãîðùèíà Martinasz u.1,2459, e-mail:sandordr@vnet.hu 3 ³íñòèòóò ãàçó ÍÀÍ Óêðà¿íè, Êè¿â, Óêðà¿íà âóë. Äåãòÿð³âñüêà, 39, 03113 Êè¿â, Óêðà¿íà, e-mail: b.soroka@gmail.com Ðîçðîáêà ìåòîäèêè ðîçðàõóíêó ç ìåòîþ ñòâîðåííÿ âèñîêîåôåêòèâíîãî ðàä³àö³éíîãî ðåêóïåðàòîðà â ðàìêàõ âèêîíàííÿ ïðîãðàìè «EUREKA» Ïðîåêò «REPLACE NG» («Çàì³ùåííÿ ïðèðîäíîãî ãàçó») íàïðàâëåíèé íà ðîçðîáêó òà âèêîðèñòàííÿ ðàä³àö³éíîãî (ðàä³àö³éíî-êîíâåêòèâíîãî) ðåêóïåðàòîðà íîâ³òíüî¿ êîíñò- ðóêö³¿ äëÿ óòèë³çàö³¿ òåïëîòè âèêèäíèõ ãàç³â ïðè ñïàëþâàíí³ ïàëèâ, ó òîìó ÷èñë³ íèçüêîêàëîð³éíèõ (LCV) ãàç³â, ó ïðîìèñëîâèõ ïå÷àõ ð³çíîãî ïðèçíà÷åííÿ. Ó â³äïî- â³äíîñò³ äî ïëàíó ðîá³ò ïåðåäáà÷àëîñÿ, ùî ðîçðîáëþâàí³ ðåêóïåðàòîðè ìàþòü áóòè ïðèäàòíèìè äî íàãð³âó ïîâ³òðÿ ãîð³ííÿ òà ñàìèõ íèçüêîêàëîð³éíèõ ãàç³â. Ðåêóïåðàòî- ðè ïîäâ³éíîãî ïðèçíà÷åííÿ ìîæóòü âèêîðèñòîâóâàòèñÿ ïðè óñòàíîâö³ íà ïå÷àõ, îïàëþ- âàíèõ íèçüêîêàëîð³éíèì ãàçîì. Òàêå îáëàäíàííÿ — ðåêóïåðàòîð òèïó ÐÐÄ — ðîçðîá- ëåíî ²íñòèòóòîì ãàçó ÍÀÍÓ (Óêðà¿íà). Ó â³äïîâ³äíîñò³ äî íàì³÷åíî¿ ïðîãðàìè òà ãðà- ô³êà ðîá³ò áóëî íàì³÷åíî çàëó÷åííÿ êîìïàí³¿ «ÒÞʲ» (Óãîðùèíà) ÿê ïàðòíåðà ïî çä³éñíåííþ ïðîåêòà íà ð³çíèõ åòàïàõ, à ñàìå: ïðè âèïðîáóâàííÿõ ðåêóïåðàòîðà, çìîí- òîâàíîãî ç ö³ºþ ìåòîþ íà êîâïàêîâ³é ïå÷³ ó öåõó õîëîäíî¿ ïðîêàòêè êîìá³íàòó «²ÑÄ ÄÓÍÀÔÅÐл. ϳä ÷àñ äîñë³äæåíü ïåðåäáà÷åíî âèïðîáóâàòè îïàëþâàííÿ ïå÷³ ð³çíè- ìè òåõíîëîã³÷íèìè ãàçàìè ìåòàëóðã³éíîãî âèðîáíèöòâà (àëüòåðíàòèâíèì ïàëèâîì). Ó ö³é ðîáîò³ ïðåäñòàâëåíî âèâåäåííÿ ðîçðàõóíêîâèõ çàëåæíîñòåé, ÿê³ çàáåçïå÷óâàòèìóòü ïðÿìå ïîð³âíÿííÿ òåïëîâîãî ñòàíó òåïëîîáì³ííèêà íîâîãî òèïó òà ðàä³àö³éíèõ ðåêóïå- ðàòîð³â òðàäèö³éíî¿ øèðîêî ðîçïîâñþäæåíî¿ êîíñòðóêö³¿. Ìåòîäèêà áàçóºòüñÿ íà ðîç- ðàõóíêó ïðîöåñ³â òåïëîîáì³íó â óìîâàõ ïðÿìî- òà ïðîòèòî÷íîãî âçàºìíîãî ðóõó òåïëî- íîñ³¿â ó êàíàëàõ. Ñïðîùåíí³ äèôåðåíö³éí³ ð³âíÿííÿ òåïëîâîãî áàëàíñó òà òåïëîîáì³íó äëÿ ð³çíèõ çîí ðåêóïåðàòîðà áóëè âèêîðèñòàí³ ÿê áàçîâà ñèñòåìà ïðè îòðèìàíí³ ðîç- ðàõóíêîâèõ çàëåæíîñòåé. Çàâäÿêè â³äøóêàííþ òà çàñòîñóâàííþ óçàãàëüíþþ÷èõ äîïî- ì³æíèõ áåçðîçì³ðíèõ ïàðàìåòð³â ðîçðàõóíêîâà ìîäåëü çàáåçïå÷óº ìîæëèâ³ñòü àíàë³çó âïëèâó êîåô³ö³ºíò³â òåïëîîáì³íó, ìàñîâîãî òà îá’ºìíîãî ïîòîê³â òåïëîíîñ³¿â òà òåïëî-  ïîñëåäíåå âðåìÿ èñïîëüçîâàíèå áèîãàçà â êà÷åñòâå òîïëèâà äëÿ ïðîìûøëåííûõ êîòëîâ ïðèîáðåòàåò âñå áîëüøóþ àêòóàëüíîñòü. Ýòî âûçâàíî êàê ìèíèìóì òðåìÿ ïðè÷èíàìè: 1) âû- ñîêîé ñòîèìîñòüþ ïðèðîäíîãî ãàçà; 2) íåîáõî- äèìîñòüþ î÷èñòêè ãîðîäñêèõ è ïðîìûøëåííûõ ñòî÷íûõ âîä, â ðåçóëüòàòå êîòîðîé êàê îñòàòî÷- íûé ïðîäóêò îáðàçóåòñÿ áèîãàç; 3) óñèëåíèåì âíèìàíèÿ ê âûáðîñó ïàðíèêîâûõ ãàçîâ, â ïåð- âóþ î÷åðåäü CO2, CH4. Êîòåëüíûé ïàðê Óêðàèíû íàñ÷èòûâàåò äå- ñÿòêè òûñÿ÷ êîòëîâ êîììóíàëüíîãî õîçÿéñòâà, íåñêîëüêî òûñÿ÷ êîòëîâ ïðîìûøëåííîñòè è ýëåêòðîñòàíöèé, áîëüøèíñòâî êîòîðûõ îñíàùå- íî ãîðåëî÷íûìè óñòðîéñòâàìè äëÿ ñæèãàíèÿ ïðèðîäíîãî ãàçà. Èñïîëüçîâàíèå áèîãàçà â ïðî- ìûøëåííûõ êîòëàõ â Óêðàèíå êðàéíå îãðàíè- ÷åíî. Ïðè ýòîì áèîãàç îáû÷íî ïîäàþò â ãîðå- ëî÷íûå óñòðîéñòâà, êîòîðûå ðàçðàáîòàíû äëÿ ïðèðîäíîãî ãàçà. Ðåæå ïðèìåíÿþòñÿ ãîðåëî÷- íûå óñòðîéñòâà, ðàçðàáîòàííûå äëÿ ñæèãàíèÿ áèîãàçà, çàðóáåæíûõ ôèðì. Ðàññìîòðèì âîçìîæíîñòü èñïîëüçîâàíèÿ äëÿ ñæèãàíèÿ áèîãàçà ñóùåñòâóþùèõ ãîðåëî÷- íûõ óñòðîéñòâ, ðàçðàáîòàííûõ äëÿ ñæèãàíèÿ ïðèðîäíîãî ãàçà.  òàáë.1 ïðèâåäåíû äàííûå Èíñòèòóòà ãàçà ÍÀÍ Óêðàèíû î ñîñòàâå áèîãàçà ðàçëè÷íîãî 68 Ýíåðãîòåõíîëîãèè è ðåñóðñîñáåðåæåíèå. 2014. ¹ 3 � Ñèãàë È.ß., Ìàðàñèí À.Â., Ñìèõóëà À.Â., 2014 âèõ ïîòîê³â íà ðåçóëüòóþ÷èé òåìïåðàòóðíèé ðîçïîä³ë â àïàðàò³ ó ïðîöåñ³ ï³ä³ãð³âó ïîâ³òðÿ. Ïåðåâàãè íîâîãî ï³äõîäó äî ïðîåêòóâàííÿ ðåêóïåðàòîð³â, íàâ³òü íå áåðó÷è äî óâàãè çðîñòàííÿ ³íòåíñèâíîñò³ òåïëîîáì³íó ç îáîõ ñòîð³í òåïëîîáì³ííî¿ ïîâåðõí³, ïî- ÿñíÿþòüñÿ ñóòòºâèì çá³ëüøåííÿì îáëàñò³ òåïëîîáì³íó (ó ðàç³ ðåêóïåðàòîðà òèïà ÐÐÄ) ó ïîð³âíÿíí³ ç³ çâè÷àéíèìè îäíîõîäîâèìè ðàä³àö³éíèìè ðåêóïåðàòîðàìè. Âèêîðèñòàí- íÿ âòîðèííèõ (ïðîì³æíèõ) àä³àáàòíèõ âèïðîì³íþâà÷³â ó êàíàëàõ äëÿ äèìîâèõ ãàç³â òà ïîâ³òðÿ (÷è ïîòîê³â íèçüêîêàëîð³éíîãî ãàçó) çàáåçïå÷óº äîäàòêîâ³ ìîæëèâîñò³ ï³ä- âèùåííÿ ï³ä³ãð³âó ïîâ³òðÿ (÷è íèçüêîêàëîð³éíîãî ãàçó). Á³áë. 11, ðèñ. 8, òàáë. 2. Êëþ÷îâ³ ñëîâà: ïîâ³òðÿ ãîð³ííÿ, êîâïàêîâà ï³÷, êîåô³ö³ºíò òåïëîâ³ääà÷³, êîåô³ö³ºíò òåïëîïåðåäà÷³, íèçüêîêàëîð³éíå ïàëèâî, ïðîòèòîê, ïðÿìîòîê, ïðîäóêòè çãîðÿííÿ, ðà- ä³àö³éíèé ðåêóïåðàòîð, òåìïåðàòóðà òåïëîíîñ³ÿ, òåïëîâèé ïîò³ê. ÓÄÊ 621.18:632.15 Ñèãàë È.ß., äîêò. òåõí. íàóê, ïðîô., Ìàðàñèí À.Â., Ñìèõóëà À.Â., êàíä. òåõí. íàóê Èíñòèòóò ãàçà ÍÀÍ Óêðàèíû, Êèåâ óë. Äåãòÿðåâñêàÿ, 39, 03113 Êèåâ, Óêðàèíà, e-mail: isigal@ukr.net Ãàçîãîðåëî÷íûå óñòðîéñòâà äëÿ ñæèãàíèÿ áèîãàçà â êîòëàõ Íà îñíîâå ïðîâåäåííûõ ðàíåå ýêñïåðèìåíòîâ âïåðâûå âûâåäåíû êðèòåðèè ïîäîáèÿ äëÿ èíæåíåðíîãî ðàñ÷åòà ãîðåëî÷íûõ óñòðîéñòâ äëÿ ñæèãàíèÿ áèîãàçà, à òàêæå åãî ñæèãàíèÿ ñîâìåñòíî ñ ïðèðîäíûì ãàçîì. Óñòàíîâëåíî, ÷òî îñíîâíîå îòëè÷èå áèîãàçà îò ïðèðîäíîãî ãàçà âûçâàíî íàëè÷èåì â åãî ñîñòàâå áîëåå 30 % óãëåêèñëîãî ãàçà è åãî âëèÿíèåì íà ïëîòíîñòü, òåïëîòâîðíîñòü ñìåñè ãàçîâ è íîðìàëüíóþ ñêîðîñòü ðàñïðî- ñòðàíåíèÿ ïëàìåíè. Ïîêàçàíî, ÷òî áåç èçìåíåíèÿ êîíñòðóêöèè è ðåæèìîâ ïîäà÷è òîï- ëèâà ñæèãàíèå áèîãàçà â ãîðåëî÷íûõ óñòðîéñòâàõ, ðàçðàáîòàííûõ äëÿ ñæèãàíèÿ ïðèðîäíîãî ãàçà, ïðàêòè÷åñêè íå âîçìîæíî. Ðàññìîòðåíî íåñêîëüêî ïðèìåðîâ ãîðåëî÷- íûõ óñòðîéñòâ äëÿ ðàáîòû íà áèîãàçå, ðàññ÷èòàííûõ äëÿ ñæèãàíèÿ ïðèðîäíîãî ãàçà. Ïðèâåäåííûå äàííûå áûëè ïîëîæåíû â îñíîâó ïåðåîáîðóäîâàíèÿ ãîðåëî÷íûõ óñò- ðîéñòâ äëÿ ñîâìåñòíîãî è ðàçäåëüíîãî ñæèãàíèÿ áèîãàçà è ïðèðîäíîãî ãàçà. Áèáë. 7, ðèñ. 2, òàáë. 2. Êëþ÷åâûå ñëîâà: áèîãàç, ãîðåëî÷íûå óñòðîéñòâà, êîòëû, êðèòåðèè ïîäîáèÿ.