GB2040414A - Boiler and waste gas exchanger - Google Patents
Boiler and waste gas exchanger Download PDFInfo
- Publication number
- GB2040414A GB2040414A GB7940751A GB7940751A GB2040414A GB 2040414 A GB2040414 A GB 2040414A GB 7940751 A GB7940751 A GB 7940751A GB 7940751 A GB7940751 A GB 7940751A GB 2040414 A GB2040414 A GB 2040414A
- Authority
- GB
- United Kingdom
- Prior art keywords
- water
- temperature
- generator
- waste gases
- heat
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 239000002912 waste gas Substances 0.000 title claims abstract description 44
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 42
- 238000011144 upstream manufacturing Methods 0.000 claims abstract description 3
- 238000010438 heat treatment Methods 0.000 claims description 23
- 238000000034 method Methods 0.000 claims description 9
- 239000008236 heating water Substances 0.000 claims description 8
- 239000007789 gas Substances 0.000 claims description 3
- 238000011084 recovery Methods 0.000 description 2
- 239000003570 air Substances 0.000 description 1
- 239000012080 ambient air Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
- F24D19/00—Details
- F24D19/10—Arrangement or mounting of control or safety devices
- F24D19/1006—Arrangement or mounting of control or safety devices for water heating systems
- F24D19/1009—Arrangement or mounting of control or safety devices for water heating systems for central heating
- F24D19/1015—Arrangement or mounting of control or safety devices for water heating systems for central heating using a valve or valves
- F24D19/1024—Arrangement or mounting of control or safety devices for water heating systems for central heating using a valve or valves a multiple way valve
- F24D19/1033—Arrangement or mounting of control or safety devices for water heating systems for central heating using a valve or valves a multiple way valve motor operated
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
- F24H15/00—Control of fluid heaters
- F24H15/20—Control of fluid heaters characterised by control inputs
- F24H15/212—Temperature of the water
- F24H15/219—Temperature of the water after heating
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
- F24H15/00—Control of fluid heaters
- F24H15/20—Control of fluid heaters characterised by control inputs
- F24H15/235—Temperature of exhaust gases
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Chimneys And Flues (AREA)
- Air Supply (AREA)
- Control Of Combustion (AREA)
- Steam Or Hot-Water Central Heating Systems (AREA)
Abstract
Waste gases are used to preheat a part 18 of the water returning to a boiler 1, which part 18 is diverted from the main return flow 8 and passed through heat exchanger 3 in heat exchange with the waste gases emerging from the boiler and reunited with the rest of the returning water upstream of the boiler. The quantity of water diverted is controlled by a valve 14 as a function of the temperature of the waste gases at the outlet of the chimney, whereby a substantially constant temperature of the waste gases at the chimney outlet is maintained at only a little above the dewpoint. <IMAGE>
Description
SPECIFICATION
A method of and a system for utilising the hot waste gases from heat generators
This invention relates to a method of utilising the hot waste gases from a fuel-fired heat generator to at least partially heat circulating heating water, whereby a part of the water returning to the generator is diverted from the main flow and preheated by heat exchange with all the hot waste gases emerging from the heat generator and is reunited with the rest of the returning water upstream of the heat generator, and to a heating system for carrying out the said method.
In a known system of the type referred to, a partial flow of cold water which has to be fed to a heating boiler is passed through a tube coil which is wound several times around the waste gas pipe from the heating boiler and which is heat insulated from the ambient air. The cold water is thus pre-heated while the waste gases are cooled to the same extent. This known principle of heat recovery does however, involve the danger that in certain operating conditions too much heat is extracted from the waste gases so that the temperature in the chimney falls below the dewpoint. The damage to the chimney resulting from this dewpoint shortfall is usually substantially greater than the benefit obtained by the recovery of heat because dewpoint shortfall will
mean that the chimney becomes faulty after quite a short time.
The invention is therefore, concerned with the propblem of obtaining optimum utilisation of the hot waste gases without the risk of the temperature in the chimney falling below the dewpoint.
According to the invention, this problem is solved by controlling the quantity of water diverted as a function of the temperature of the waste gases at the outlet of the chimney, whereby the quantity of water diverted is reduced when the chimney outlet temperature drops and is increased again when the chimney outlet temperature rises, so that under changing waste gas conditions, a substantially constant temperature of the waste gases at the chimney outlet is maintained at only a little above the dewpoint.
This measure makes it possible to extract from the waste gases an amount of heat which is insufficient to make the temperature in the chimney fall below the dewpoint and therefore, avoid damage to the chimney. Variations in the condition of the waste gases are compensated by varying the amount of water diverted from the main flow of return water and passed through the heat exchanger to absorb the heat from the waste gases so that this quantity is adapted to the maximum quantity of heat which the waste gases can provide.
When the operating conditions involve only small quantities of waste gases and/or low waste gas temperatures, an extreme case may on occasion arise in which the partial flow requires to be shut off completely in order to achieve a sufficiently high waste gas temperature in the chimney outlet. Under such operating conditions, there is however, the danger that the residual water remaining in the heat exchanger might be heated to an unacceptably high level. In orderto guarantee that the residual water in the heat exchanger never exceeds a temperature of for instance, 11 0 C, the quantity of water diverted can be increased as a function of the water temperatu re in the heat exchanger, even at the risk of the dewpoint in the chimney occasionally not being attained in a few exceptional circumstances.Alternatively, however, if an inadmissibly high water temperature is reached in the heat exchanger, the burner of the heat generator could be switched off briefly.
The heating system for carrying out the method according to the invention expediently comprises a fuel-fired heat generator serving at least partially to heat circulating heating water, a heat exchanger interposed in the path of waste gases from the generator, for preheating a part of the water returning to the generator, and means for diverting a part of the water returning to the generator, through said heat exchanger and returning it to the main return line at a point between its point of diversion and the generator, and is characterised by a motorised three-way valve located at the point of diversion and controlled by a control unit which is connected to a temperature sensor which detects the temperature of the waste gases passing through the chimney outlet.
The temperature sensor can be located adjacent the chimney outlet, in which case, it directly determines the gas temperature at the chimney outlet.
However, the temperature sensor can be located below the chimney outlet, in which case, the temperature controller must be adjusted to take into account a correction factor for the temperature dependent upon the insulation and height of the chimney.
In order to avoid the water becoming heated to an inadmissibly high temperature in the heat exchanger under certain extreme conditions, a second temperature sensor may be provided at the outlet end of the heat exchanger for measuring the temperature of the partial flow of water leaving the heat exchanger and operable through the control unit to prevent the temperature of the water in the heat exchanger from exceeding a predetermined maximum.
The invention will be described, by way of example, with reference to the accompanying diagrammatic drawing which shows a heating system for water central heating.
As shown in the drawing, the heating system includes a heating boiler 1 having a burner 2 to which gas or oil is supplied according to requirements. The waste gases from the heating boiler 1 pass in their entirety into a heat exchanger 3, immediately downstream of the heating boiler 1, from which they pass to a chimney 5 via a waste gas pipe 4.
The heating boiler, which may be of any suitable construction, is provided with an inlet connection 6 and an outlet connection 7, to which a heating water return line 8 and heating water feed line 9 are respectively connected.
The heat exchanger 3 contains a nest of parallel vertically disposed tubes 10 connected at their lower ends to a common water inlet 11 and at their upper
ends to a common water outlet 12.
The waste gases emerging from the heating boiler
1 are introduced through an inlet connecter 13 into the lower end of the heat exchanger from whence they circulate transversely around the watercarrying vertical tubes 10. After heat exchange, the waste gases flow transversely of the vertical tubes
10 out of the upper zone of the heat exchanger 3 into the waste gas pipe 4, from whence they pass into the outside air via the chimneys.
The heating water return line 8 contains a motorised three-way valve 14 having an outlet 15 connected via a direct main line 16 to the inlet connection 6 of the heating boiler 1 and an outlet 17 connected via a flow line 18 to the water inlet 11 of the waste gas heat exchanger 3. The partial flow of water diverted through the line 18 is preheated in the heat exchanger3 and leaves through the outlet 12 connected to the main line 16 by a line 19 which joins the main line at a location between the three-way valve 14 and the inlet connection 6 of the heating boiler 1.
To control the motorised three-way valve 14, a temperature controller 20 or other suitable control unit is provided which communicates with a temperature sensor 21 by which the chimney outlet temperature is measured directly or indirectly.
In order to utilise the waste gases as much as possible, the plant is so operated that the chimney outlet temperature is always above the dewpoint.
This is achieved by reducing the quantity of the diverted partial flow when the chimney outlet temperature drops and increasing said partial flow when the chimney outlet temperature rises. Variations in the waste gas condition are thus taken into account automatically so that the system operates under optimum conditions both under full load and also under any desired partial load of the heating boiler 1.
On grounds of safety, there is provided, close to the outlet from which the preheated partial flow of water leaves the heat exchanger, a second temperature sensor 22 which likewise communicates with the temperature controller 20. The temperature sensor 22 monitors the water temperature in the heat exchanger 3 and when a predetermined maximum water temperature in the heat exchanger 3 is exceeded, it transmits a signal to the controller 20.
Under unfavourable conditions, the maximum water temperature may be exceeded in the event of an interruption in the partial flow of water passing through the heat exchanger 3. In such a case, the partial flow of water is briefly restarted or increased independently of the chimney outlet temperature.
By means of the heating system illustrated in the drawing, it is possible, with minimal expenditure on equipment, to achieve the greatest possible cooling of all the waste gases emerging from the heating boiler by passing the waste gases in heat exchange with a variable portion of the water returning to the boiler.
It is obvious that the invention can also be used in other heating systems within the scope of the appended claims.
Claims (8)
1. A method of utilising the hot waste gases from a fuel-fired heat generator to at least partially heat circulating heating water, whereby a part of the water returning to the generator is diverted from the main flow and preheated by heat exchange with all the hot waste gases emerging from the heat generator and is reunited with the rest of the returning water upstream of the heat generator, characterised in that the quantity of water diverted is controlled as a function of the temperature of the waste gases at the outlet of a chimney through which the waste gases are discharged, whereby the quantity of water diverted is reduced when the chimney outlet temperature drops and is increased again when the chimney outlet temperature rises, so that under changing waste gas conditions, a substantially constant temperature of the waste gases at the chimney outlet is maintained at only a little above the dewpoint.
2. A method according to Claim 1, characterised in that when operating conditions involve only small quantities of waste gas and/or low waste gas temperatu res, the quantity of water diverted is increased whenever a predetermined upper temperature thereof is exceeded.
3. A heating system for carrying out the method according to Claim 1, comprising a fuel-fired heat generator serving at least partially to heat circulating heating water, a heat exchanger interposed in the path of waste gases from the generator for preheating a part of the water returning to the generator and means for diverting a part of the water returning to the generator, through said heat exchanger and returning it to the main return line at a point between its point of diversion and the generator, characterised by a motorised three-way valve located at the point of diversion and controlled by a control unit which is connected to a temperature sensor which detects the temperature of the waste gases passing through the chimney outlet.
4. A heating system according to Claim 3, characterised in that the temperature sensor is located adjacent the chimney outlet.
5. A heating system according to Claim 3, characterised in that the temperature sensor is located below the chimney outlet.
6. A heating system according to any one of
Claims 3 to 5, characterised by a second temperature sensor at the outlet end of the heat exchanger for measuring the temperature of the partial flow of water leaving the heat exchanger and operable through the control unit to prevent the temperature of the water in the heat exchanger from exceeding a predetermined maximum.
7. A method of utilising the hotwaste gases from a fuel-fired heat generator to at least partially heat circulating heating water, substantially as hereinbefore described with reference to the accompanying drawing.
8. A heating system for carrying out the method claimed in Claim 1, substantially as hereinbefore described with reference to the accompanying drawing.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE2851206A DE2851206C3 (en) | 1978-11-27 | 1978-11-27 | Heating system with a boiler and a flue gas-heated water heater for heating part of the flow of the heating water return |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB2040414A true GB2040414A (en) | 1980-08-28 |
Family
ID=6055633
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB7940751A Withdrawn GB2040414A (en) | 1978-11-27 | 1979-11-26 | Boiler and waste gas exchanger |
Country Status (7)
| Country | Link |
|---|---|
| AT (1) | AT379015B (en) |
| BE (1) | BE887858Q (en) |
| CH (1) | CH643346A5 (en) |
| DE (1) | DE2851206C3 (en) |
| GB (1) | GB2040414A (en) |
| IT (1) | IT1120891B (en) |
| NL (1) | NL7908016A (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4373473A (en) * | 1981-03-16 | 1983-02-15 | 110707 Canada Ltee | Heat recuperating water heating system |
| GB2129915A (en) * | 1982-11-16 | 1984-05-23 | Baxi Partnerships Ltd | A gas operated boiler |
| US4512288A (en) * | 1983-07-15 | 1985-04-23 | Roger Michaud | Furnace heat exchanger |
| GB2188715A (en) * | 1986-01-17 | 1987-10-07 | Thermon Limited | Central heating boiler arrangement |
| US5555849A (en) * | 1994-12-22 | 1996-09-17 | Combustion Engineering, Inc. | Gas temperature control system for catalytic reduction of nitrogen oxide emissions |
| GB2373841A (en) * | 2001-03-30 | 2002-10-02 | Aquaflame Ltd | Secondary heat exchange unit |
| GB2373839A (en) * | 2001-03-30 | 2002-10-02 | Andrew John Robertson | Boiler with secondary heat exchange unit |
| CN114110736A (en) * | 2021-11-25 | 2022-03-01 | 广西电网有限责任公司电力科学研究院 | Non-contact heat exchange steam supply method for extracting steam at different steam temperatures |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3013423C2 (en) * | 1980-04-05 | 1985-03-07 | Huras, Hans, 6437 Kirchheim | Device for heat recovery from hot exhaust gases |
| DE3220554C2 (en) * | 1982-06-01 | 1985-12-19 | Könnyüipari Szerelö és Epítö Vállalat, Budapest | Device for utilizing at least part of the heat content of the exhaust gases emerging from a fired boiler |
| DE3644629A1 (en) * | 1986-12-29 | 1988-07-07 | Reininger Gmbh | Vertical flow-heat distributor with heat recovery and harmful-substance reduction |
| DE3700103A1 (en) * | 1987-01-03 | 1988-07-14 | Meulenaer Hubert De | Device for saving energy in oil/gas boilers |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2048673A1 (en) * | 1970-10-03 | 1972-04-06 | Daniel, Waldemar, 6238 Hoflieim | Device for better utilization of the thermal energies to be generated by oil or gas heating |
| DE7710693U1 (en) * | 1977-04-04 | 1977-11-10 | Weinberg, Matthias, 5340 Bad Honnef | DEVICE FOR PARTIAL HEATING OF THE RETURN WATER OF A CENTRAL HEATING SYSTEM BEFORE RE-ENTRY INTO THE BOILER |
-
1978
- 1978-11-27 DE DE2851206A patent/DE2851206C3/en not_active Expired
-
1979
- 1979-11-01 NL NL7908016A patent/NL7908016A/en not_active Application Discontinuation
- 1979-11-02 AT AT0706979A patent/AT379015B/en not_active IP Right Cessation
- 1979-11-23 CH CH1046479A patent/CH643346A5/en not_active IP Right Cessation
- 1979-11-23 IT IT50900/79A patent/IT1120891B/en active
- 1979-11-26 GB GB7940751A patent/GB2040414A/en not_active Withdrawn
-
1981
- 1981-03-09 BE BE0/204059A patent/BE887858Q/en not_active IP Right Cessation
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4373473A (en) * | 1981-03-16 | 1983-02-15 | 110707 Canada Ltee | Heat recuperating water heating system |
| GB2129915A (en) * | 1982-11-16 | 1984-05-23 | Baxi Partnerships Ltd | A gas operated boiler |
| US4512288A (en) * | 1983-07-15 | 1985-04-23 | Roger Michaud | Furnace heat exchanger |
| GB2188715A (en) * | 1986-01-17 | 1987-10-07 | Thermon Limited | Central heating boiler arrangement |
| GB2188715B (en) * | 1986-01-17 | 1989-10-18 | Thermon Limited | Central heating systems |
| US5555849A (en) * | 1994-12-22 | 1996-09-17 | Combustion Engineering, Inc. | Gas temperature control system for catalytic reduction of nitrogen oxide emissions |
| GB2373841A (en) * | 2001-03-30 | 2002-10-02 | Aquaflame Ltd | Secondary heat exchange unit |
| GB2373839A (en) * | 2001-03-30 | 2002-10-02 | Andrew John Robertson | Boiler with secondary heat exchange unit |
| GB2373841B (en) * | 2001-03-30 | 2003-05-07 | Aquaflame Ltd | Heat exchanger for fossil fuel fired boiler |
| GB2373839B (en) * | 2001-03-30 | 2003-09-10 | Andrew John Robertson | Fossil fuel fired boiler |
| CN114110736A (en) * | 2021-11-25 | 2022-03-01 | 广西电网有限责任公司电力科学研究院 | Non-contact heat exchange steam supply method for extracting steam at different steam temperatures |
| CN114110736B (en) * | 2021-11-25 | 2023-02-28 | 广西电网有限责任公司电力科学研究院 | Non-contact heat exchange steam supply method for extracting steam at different steam temperatures |
Also Published As
| Publication number | Publication date |
|---|---|
| IT1120891B (en) | 1986-03-26 |
| NL7908016A (en) | 1980-05-29 |
| BE887858Q (en) | 1981-07-01 |
| DE2851206B2 (en) | 1980-09-11 |
| ATA706979A (en) | 1985-03-15 |
| CH643346A5 (en) | 1984-05-30 |
| AT379015B (en) | 1985-11-11 |
| DE2851206C3 (en) | 1981-05-21 |
| DE2851206A1 (en) | 1980-05-29 |
| IT7950900A0 (en) | 1979-11-23 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4318366A (en) | Economizer | |
| RU2467250C2 (en) | Operating method of combined-cycle turbine plant, and combined-cycle turbine plant designed for that purpose | |
| US4592293A (en) | Method of controlling an air heater of a coal-fired boiler | |
| GB2040414A (en) | Boiler and waste gas exchanger | |
| JP2791985B2 (en) | Waste heat treatment equipment and method of operating the equipment | |
| JP2012017965A (en) | Boiler system | |
| US5161488A (en) | System for purifying contaminated air | |
| US4661684A (en) | Asphalt heating system | |
| KR0147059B1 (en) | System and method for reheat steam temperature control in circulating fluidized bed boilers | |
| US3273520A (en) | Method and apparatus for air temperature regulation | |
| GB2099558A (en) | Heat recovery steam generator | |
| JPS6153530B2 (en) | ||
| AU597783B2 (en) | Process of conditioning dust-containing exhaust gases | |
| US1940355A (en) | Furnace control | |
| US4416256A (en) | Solar water heaters | |
| US6401459B1 (en) | Fuel gas conditioning system with dew point monitoring | |
| JPS5997449A (en) | Heating control device | |
| US2875736A (en) | Gas recirculation method and automatic apparatus for superheat control | |
| PL97850B1 (en) | KEEPING COAL HEATING DEVICES AT A SET TEMPERATURE | |
| US3730261A (en) | Water heating system | |
| US4358052A (en) | Hot-water central heating system | |
| US3150827A (en) | Apparatus for use in hot water heating systems | |
| CN204165066U (en) | Exhaust smoke processing device | |
| RU2099542C1 (en) | Steam power plant and method of control of same | |
| JP2965265B2 (en) | Method of temperature control in PFBC plant |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |