WO2018099345A1 - Low calorific value coal gas power generation system and power generation method - Google Patents

Abstract

Provided is a low calorific value coal gas power generation system, comprising: a coal gas boiler (1) and a power generator set (2); the power generator set comprises a steam turbine (21) and a power generator (22), while the coal gas boiler comprises a furnace body (11) and a boiler drum (12), the furnace body comprising a horizontal flue (113) and a vertical flue (114), and the furnace body being provided thereon with a water cooling wall (115), wherein the water cooling wall (115) communicates with a liquid outlet and a steam inlet of the boiler drum; the furnace body (11) is also provided therein with a superheater unit (13) and an economizer unit (14), the superheater unit communicating with a steam outlet of the boiler drum (12) and an inlet of a high-pressure cylinder (211) of the steam turbine (21), while the economizer unit (14) communicates with a waste steam outlet of the steam turbine (21) and a liquid inlet of the boiler drum (12); also provided is a power generation method: stably burning low calorific value coal gas by means of a burner (112); first heating liquid water in the water cooling wall (115) to a vapor state; then using the superheater unit (13) to heat the steam to superheated steam, and using work of the superheated steam to generate power; the solution may stabilize steam and water parameters, which may not only ensure safety, but may also improve the power generating efficiency of low calorific value coal gas, while heat utilization rate is relatively high.

Description

Low calorific value gas power generation system and power generation method Technical field

The invention relates to gas power generation, in particular to a low calorific value gas power generation system and a power generation method.

Background technique

China's steel industry has developed rapidly and has been ranked as the world's largest producer for many years. Iron and steel enterprises produce a large amount of by-product gas during the smelting process, such as blast furnace gas, converter gas and coke oven gas. Coke oven gas and converter gas can be effectively utilized in production and life due to their high calorific value. The blast furnace gas has the characteristics of maximum output, lowest calorific value, difficulty in stable combustion, and low power generation efficiency.

Blast furnace gas is a colorless, odorless and odorless gas mixture. The main components are CO, CO ₂ , N ₂ , H ₂ , CH _{4 ,} etc., wherein the combustible component CO content accounts for about 25%; H ₂ and CH ₄ content Rarely, it has little effect on total calorific value; the contents of inert gas CO ₂ and N ₂ account for 15% and 55% respectively (both in volume fraction), which account for a high proportion, and neither participate in combustion to generate heat, nor can it support combustion. On the contrary, it also absorbs a large amount of heat generated during the combustion process; the flame is long; the temperature at the ignition point is about 700 ° C; the flame propagation speed is very slow, the temperature is not high, and the combustion stability is not good; the heating value is generally 3100 kJ/Nm ³ - 4200kJ/Nm ³ , the amount of smoke is large. Therefore, the effective conversion and utilization of blast furnace gas is an important part of steel enterprises' clean production and energy conservation.

Based on blast furnace gas fuel and combustion characteristics, blast furnace gas is significantly different from other high calorific value solid or gaseous fuels. The heat transfer characteristics of gas boilers vary greatly, and the heating surface layout is significantly different from that of coal-fired gas boilers. Although the patent "a full-burning blast furnace gas boiler flue gas waste heat recovery and utilization system" (application number: 201320444475.0) and "a full-burning blast furnace gas boiler flue gas waste heat recovery system" (application number: 201320446384.0) announced the relevant blast furnace Gas boiler flue gas waste heat recovery and utilization system, however, it only focuses on improving the recovery and utilization of flue gas side waste heat, but does not consider the heat transfer and heating surface arrangement of gas boilers due to the low calorific value of blast furnace gas and difficult to stabilize combustion. The core important issues are not considered, and how to improve the efficiency of low calorific value gas power generation through the optimization of the steam-water side process.

At the same time, many blast furnace gas boilers have a desuperheating water usage at high load, which far exceeds the design value, especially in the case of gas boiler load rise or high-load gas boiler load fluctuation, there is desuperheated water can not keep up, gas boiler The problem that the superheater is heated and the surface is easy to overheat. To this end, it is necessary to arrange various heating surfaces of the blast furnace gas boiler, including the arrangement of the heating surface and the proportion of the heating surface, so as to solve the problem that the heating surface of the gas boiler superheater is easy to overheat, stabilize the steam and water parameters, and improve the low heat value. The overall thermal efficiency of the gas power plant.

Summary of the invention

The object of the present invention is to provide a low calorific value gas power generation system, which is intended to solve the thermal efficiency of the existing low calorific value gas. Low problem.

The present invention is implemented as follows:

Embodiments of the present invention provide a low calorific value gas power generation system including a gas boiler and a generator set, the generator set including a steam turbine connected to the gas boiler pipeline and a generator driven by the steam turbine, the gas boiler including a furnace body having a built-in combustion chamber and a steam-steamable drum, the furnace body comprising a horizontal flue above the combustion chamber and a vertical flue communicating with the horizontal flue, the furnace body being provided with a water-cooling wall, at least one port of the water-cooling wall is in communication with a liquid outlet of the drum, at least one port is in communication with a vapor inlet of the drum, and is disposed in the horizontal flue and the vertical flue, respectively a superheating unit and an economizer unit, wherein the superheating unit communicates with a vapor outlet of the drum and a high pressure cylinder inlet of the steam turbine, and the economizer unit communicates with a steam outlet of the steam turbine and the drum a liquid inlet, and a condenser is disposed on the pipeline between the economizer unit and the steam turbine.

The embodiment of the invention further provides a low calorific value gas power generation method, comprising the following steps:

The low calorific value gas is sent from the gas pipeline to the combustion chamber of the gas boiler through the burner for combustion, and heat is generated by combustion to heat the heated surfaces;

The water in a drum is discharged through the liquid outlet, and is sent to the water wall of the furnace body of the gas boiler through a pipe, and the water is heated in the water wall, and the phase is changed into a steam-water mixture, and is sent back through the pipeline. Pot drum

The steam-water mixture is subjected to steam-water separation in the drum, and the separated saturated steam is sent to the ceiling pipe through the pipeline, and the saturated steam is introduced into the superheating unit in the furnace body through the ceiling pipe to continue heating to superheated steam;

The superheated steam is sent to the high pressure cylinder of the steam turbine through the pipeline, and the steam rushes the blades of the steam turbine, and the steam turbine drives the generator to generate electricity, and the steam temperature and pressure are reduced after the work is performed;

The steam coming out of the high-pressure cylinder enters a low-temperature reheater, and then enters a high-temperature reheater to be heated again to superheated steam, and the superheated steam is introduced into the low-pressure cylinder of the steam turbine, and after the work is performed, the steam temperature and The pressure is lowered again;

The spent steam from the low pressure cylinder of the steam turbine enters the condenser for condensation, is condensed into water in the condenser, and then the water is pumped into the low pressure heater by the condensate pump, where it is Low-pressure extraction steam heating of the turbine;

The water from the low-pressure heater enters the deaerator, and after the deaerator is deaerated, the high-pressure heater is driven by the feed water pump, and is heated by the high-pressure extraction steam of the steam turbine in the high-pressure heater, after which Enter the main economizer;

After the main economizer is heated by the flue gas, the water liquid enters the bypass economizer, is further heated, and is re-introduced into the drum for recycling.

The invention has the following beneficial effects:

In the power generation system of the present invention, the low calorific value gas first enters the combustion chamber of the furnace body, and is burned and released by the burner, and the liquid water in the drum is guided from the liquid outlet to the water wall of the furnace body. Low calorific value gas combustion releases heat to heat water cooling The liquid water in the wall further changes the endothermic phase of the liquid water into a gaseous state, and the water vapor mixture in the water wall is re-introduced into the drum for water vapor separation, wherein the separated liquid is reheated through the liquid outlet into the water wall. The steam enters the superheating unit and is heated to superheated steam. The superheated steam can be introduced into the steam turbine for power generation. After the work is completed, the spent steam is condensed into liquid water by the condenser, and then heated into the economizer unit to heat up, and the liquid water after heating is heated. It is recycled into the drum. In the above process, the low-calorific value gas is stably burned by the burner, and the liquid water in the water wall is first heated to a gaseous state, and then the steam is heated to superheated steam by using a superheating unit, and the superheated steam is used for power generation to stabilize the steam and water parameters. To ensure safety, it can also improve the power generation efficiency of low calorific value gas, the power generation efficiency can reach more than 37%, and the heat utilization rate is relatively high.

DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the description of the prior art will be briefly described below. Obviously, the drawings in the following description are only It is a certain embodiment of the present invention, and other drawings can be obtained from those skilled in the art without any creative work.

1 is a schematic structural diagram of a low calorific value gas power generation system according to an embodiment of the present invention;

2 is a schematic flow chart of the low calorific value gas power generation system of FIG. 1.

detailed description

The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, but not all embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

Referring to FIG. 1 and FIG. 2, an embodiment of the present invention provides a low calorific value gas power generation system, including a gas boiler 1 and a generator set 2. The low calorific value gas can be introduced into the gas boiler 1 for combustion, and then the heat generated by the low calorific value gas combustion is utilized. Power generation by the genset 2 includes a steam turbine 21 and a generator 22, and the steam turbine 21 includes a high pressure cylinder 211. The heat generated by the combustion of the low calorific value gas in the gas boiler 1 can heat the liquid water into steam, thereby introducing steam into the high pressure. The cylinder 211 drives the steam turbine 21 to work, and then the steam turbine 21 drives the generator 22 to generate electricity, and the steam works as the exhaust steam from the exhaust steam outlet and is exported for reuse. The structure of the gas boiler 1 is refined, which comprises a furnace body 11 having a built-in combustion chamber 111 and a drum 12 capable of separating the steam and water. A burner 112 is disposed in the combustion chamber 111, and the low calorific value gas is introduced into the combustion chamber 111 by the burner 112. The igniting heat is emitted. Generally, a plurality of burners 112 are disposed in the combustion chamber 111, and can be arranged in layers on the front and rear walls of the combustion chamber 111 through the burner 112. For example, two layers can be arranged on the front wall, and the rear wall is arranged. There is one layer, and each layer is sequentially arranged with three burners 112. By this arrangement, the low calorific value gas entering the combustion chamber 111 can be completely burned, and the combustion chamber 111 can be used. The coke oven gas is used as the ignition material, and the high-energy igniter is used as the igniter. Each burner 112 is provided with a high-energy igniter and a coke oven air gun. The high-energy igniter is used to ignite the coke oven gas to ignite the corresponding burner 112. The low-calorific gas is ignited by the burner 112. The upper burner 112 can be ignited by the lower burner 112 without using an igniter, and each burner 112 is in the form of a double-swirl structure, which can realize the combustion of low-calorific gas. In order to ensure the safety of combustion, a hole for the flame detecting device is left on each burner 112 bracket for configuring the fire detecting device to ensure the safety of the gas boiler 1 during the combustion process; and the drum 12 is located outside the furnace body 11, The utility model can realize the steam-water separation effect, and adopts a single-stage evaporation system, in which the cyclone separator, the cleaning orifice plate, the top corrugated plate separator and the top perforated plate are arranged in the drum 12, and when the steam-water mixture is introduced into the drum 12, The steam and the water in the steam-water mixture can be sufficiently separated by the above separate separation devices, and the steam is filled in the upper space of the drum 12, and the water is located in the drum 12 In the lower space, the drum 12 is provided with two two-color water level gauges, two electric water level gauges, and three single-room water level balance containers, which are used to ensure good steam quality and timely treatment of the drum 12 full of water, usually in The drum 12 is also equipped with a phosphate dosing tube, a continuous drain pipe and an emergency drain pipe for water quality protection. The structure of the furnace body 11 is further refined, and the main structure adopts double-frame all-steel welding, and the internal space further includes a horizontal flue 113 and a vertical flue 114, and the horizontal flue 113 is located above the combustion chamber 111, which communicates with the combustion chamber. 111 and the vertical flue 114, and the combustion chamber 111 is disposed opposite to the vertical flue 114, and the three are enclosed to form a π type, and the flue gas generated after the combustion of the low calorific value gas sequentially passes through the combustion chamber 111, the horizontal flue 113, and the vertical The straight flue 114 discharges the gas boiler 1, and of course, the flue gas discharged from the gas boiler 1 needs to be further purified and discharged to the atmosphere, and the full-membrane water-cooling wall 115 is disposed on the furnace body 11, and the ceiling pipe and the package are also arranged. The wall tube and the steam separated in the drum 12 first enter the ceiling tube and the wall tube, and are then distributed to the subsequent superheating unit 13. The ceiling tube and the wall tube are both made of a film tube with a flat tube and water cooled. The wall 115 has at least one port communicating with the liquid outlet of the drum 12. Generally, the water wall 115 has a plurality of ports communicating with the liquid outlet of the drum 12, and the water in the drum 12 can enter the water wall 115 through the corresponding pipe. And the water wall 115 also has One port is connected to the vapor inlet of the drum 12, the water wall 115 is welded from the flat tube by using the light pipe, and the refractory belt is applied on the water wall 115, and the weight of the water wall 115 of the furnace body 11 passes through the upper header. Suspended by a boom on the top beam, the inclined water wall 115 is suspended from the top steel frame by a lead pipe passing through the horizontal flue 113, and the entire furnace body 11 is heated and then expanded downward together, and at the water wall 115. A ring of rigid beams is arranged around the outer side every 3 m in the height direction to increase the rigidity of the water wall 115 and meet the design pressure requirements of the combustion chamber 111. Further, the horizontal flue 113 and the vertical flue 114 are respectively provided with a superheating unit 13 and an economizer unit 14, both of which are located on the flue of the low calorific value gas combustion to generate flue gas, wherein the superheating unit 13 communicates with the drum The steam outlet of 12 and the inlet of the high pressure cylinder 211 of the steam turbine 21, the steam separated in the drum 12 first enters the above-mentioned ceiling pipe, and part of the steam enters the wall pipe to be heated, and the heated steam enters the superheating unit 13 and is heated again. The superheated steam is then introduced into the steam turbine 21 for work, and the economizer unit 14 is connected to the spent steam outlet of the steam turbine 21 and the liquid inlet of the drum 12, and between the economizer unit 14 and the steam turbine 21 A condenser 23 is disposed on the road, and when the flue gas generated after the combustion of the low calorific value gas flows along the horizontal flue 113 and the vertical flue 114 to the economizer unit 14, it also has a higher temperature, and the superheated steam is Work in the steam turbine 21 After that, the exhausted steam is discharged from the exhaust steam outlet, and is liquefied into a water liquid by the condenser 23, and then introduced into the economizer unit 14, and then the liquid water can be heated by the economizer unit 14, and the heated liquid is introduced. The drum 12 is recycled.

In the present invention, low calorific value gas is introduced into the combustion chamber 111 of the furnace body 11, and is ignited by the burner 112, while the water liquid in the drum 12 flows through the liquid outlet to the water wall 115, due to the low calorific value gas. The flue gas is generated during combustion and is accompanied by a large amount of heat release, and the water in the water-cooling wall 115 can be heated by the part of the heat, so that part of the water-liquid phase becomes steam, and then the soda-water mixture is re-introduced into the drum 12 The vapor-liquid separation is generally disposed in the furnace body 11 with an evaporation convection tube screen 116, which is a spiral fin tube, which is fixed on the top steel frame by hanging, and the two ends of the evaporation convection tube screen 116 are respectively connected to the drum. The liquid outlet of 12 and the inlet of the vapor, the water in the drum 12 is diverted into the evaporating convection pipe 116 in the process of leading to the water wall 115, and is heated to steam, evaporating the soda in the convection pipe 116. The mixture is also introduced into the drum 12 for vapor-liquid separation, and the separated water liquid is further guided to the water-cooling wall 115 or the evaporation convection pipe screen 116 for reheating, and the separated steam is led to the superheater. 13 is also heated again, so that the steam can be heated to superheated steam, and the superheated steam can be led to the steam turbine 21 for power generation. The superheated steam after work is generated as the exhaust steam is derived from the exhaust steam outlet of the steam turbine 21. The spent steam enters the condenser 23 and is liquefied to a water temperature of about 40 ° C, and then is driven into the low pressure heater 25 by the condensate pump 24, heated by the low pressure steam of the steam turbine in the low pressure heater 25, and discharged from the low pressure heater 25 The water enters the deaerator 26, is deaerated by the deaerator 26, is pumped into the high pressure heater 28 through the feed water pump 27, is heated by the high pressure extraction of the turbine in the high pressure heater 28, and is then introduced into the province. The coal unit 14 is heated again, and the heated water is introduced into the drum 12 and recycled in sequence according to the above steps. In the above process, the burner 112 in this manner ignites the low calorific value gas, so that the low calorific value gas can be stably burned in the combustion chamber 111, and after the low calorific value gas is ignited by the burner 112, the released heat is first The water wall 115 is heated or the water in the convection tube panel 116 is evaporated, and then the steam can be heated at the superheating unit 13. Finally, the water after the work can be heated at the economizer unit 14, the heat is used multiple times, and the whole The heat of the low calorific value gas in the process is located in the furnace body 11, which is not easy to be lost, can effectively ensure the overall thermal efficiency of the power generation system, and strengthen the steam-water heat exchange.

The above embodiment is optimized, and a reheater unit 15 is provided in the furnace body 11, and the reheater unit 15 is connected to the inlet of the low pressure cylinder 212 of the steam turbine 21 and the outlet of the high pressure cylinder 211 of the steam turbine 21. In the present embodiment, the general steam turbine 21 further includes a low pressure cylinder 212. The superheated steam is introduced into the inlet of the high pressure cylinder 211 to generate power, and the steam after the work can be led out from the outlet of the high pressure cylinder 211, and is circulated in the high pressure cylinder 211 due to the superheated steam. The work is performed, and the steam pressure and temperature discharged from the outlet of the high pressure cylinder 211 are both lowered, and this can be introduced into the reheater unit 15 to be reheated into superheated steam, and the superheated steam can be introduced into the low pressure cylinder 212 to perform the work again. The steam temperature and pressure are again lowered, which can be referred to as spent steam, and the spent steam is introduced into the condenser 23 from the spent steam outlet to be liquefied into water. In this regard, by adding the reheater unit 15, the utilization rate of the superheated steam can be increased, and the overall thermal efficiency of the low calorific value gas to the power generation system can be ensured.

The structure of the reheater unit 15 is refined, which includes a low temperature reheater 151 installed in the vertical flue 114, to which the high pressure cylinder 211 outlet of the steam turbine 21 is connected. The low temperature reheater 151 also adopts the structural form of the spiral fin tube, and the reverse In the flow arrangement, the steam in the steam turbine 21 is discharged from the outlet of the high pressure cylinder 211 and enters the inlet header of the low temperature reheater 151. A desuperheater may be disposed at the inlet header, that is, the steam discharged from the high pressure cylinder 211 first enters the low temperature and then reheats. The temperature in the inlet header of the device 151 is adjusted by a desuperheater, and the desuperheater mainly adopts water spray temperature adjustment, finely adjusts the steam temperature, and the steam after the desuperheating enters the low temperature reheater 151 for heating. The reheater unit 15 further includes a high temperature reheater 152 disposed in the horizontal flue 113, which communicates with the low temperature reheater 151 and the low pressure cylinder 212 inlet, since the horizontal flue 113 is located vertically The flue 114 is directed forward of the flue gas flow, and the temperature at the horizontal flue 113 is higher than the temperature at the vertical flue 114. The steam discharged from the high pressure cylinder 211 is first heated into the low temperature reheater 151, and then introduced into the high temperature and then reheated. The heater 152 is heated, and the steam heated by the high temperature reheater 152 is superheated steam, which can be led to the low pressure cylinder 212 in the steam turbine 21 for work. The high temperature reheater 152 adopts a light pipe structure and is arranged in a side-by-side arrangement, and is opposite to the arrangement direction of the low temperature reheater 151, so that the heat absorption efficiency can be improved. In addition, the furnace body 11 performs flue adjustment corresponding to the reheater unit 15, and the double flue design is performed in the vertical flue 114 of the furnace body 11, and then a flue gas baffle 161 is disposed at the end of the double flue. The opening degree of the flue gas baffle 161 is adjusted to realize the distribution of the amount of flue gas in the two flue gases, and the purpose of adjusting the reheat steam temperature by the reheater unit 15 can be achieved, so that the temperature and pressure of the reheat steam are very stable.

Further, the structure of the economizer unit 14 is refined, including a main economizer 141 installed at the bottom of the vertical flue 114 and a bypass economizer 142 located above the main economizer 141. In communication, the bypass economizer 142 may be two, and the two are connected in parallel. The main economizer 141 is respectively connected to the two bypass economizers 142 through two flow paths, and the outlet of the condenser 23 is connected to the main economizer. 141, and one of the ports of the bypass economizer 142 is connected to the liquid inlet of the drum 12, and the bypass economizer 142 and the low temperature reheater 151 are arranged side by side, respectively, in the double flue of the vertical flue 114 In the road, and the two are separated by the superheater partition wall 16, usually a membrane type partition wall structure, part of the steam entering the ceiling tube can enter the superheater partition wall 16 to be heated, and the heated steam can enter the superheating unit 13 The inside is heated again to superheated steam, and the flue gas flow between the bypass economizer 142 and the low temperature reheater 151 corresponding to the flue is adjusted by the above-mentioned flue gas baffle 161, and the main economizer 141 is located in the double flue. Below the end. In this embodiment, the flue gas flows along the bypass economizer 142 in the direction of the main economizer 141, and the water discharged from the condenser 23 flows from the main economizer 141 to the bypass economizer 142, thereby realizing The working medium and the flue gas are mutually countercurrent, and the main economizer 141 and the bypass economizer 142 are both spiral fin tube structures, wherein the main economizer 141 is arranged in a staggered arrangement, and the bypass economizer 142 is Arranged in line, the bypass economizer 142 adopts a suspended structure, and all the weights are fixed on the wall wall pipe by the hanging device, and then suspended from the top steel frame through the wall pipe header box, and the main economizer 141 Resting on the ventilation beam, the ventilation beam passes through the furnace body 11 and is supported on the furnace body 11 shield. In addition, during operation, after the water supplied from the feed water pump 27 is heated in the main economizer 141, a part of the liquid liquid can be directly guided into the drum 12 as the washing water as needed.

The above embodiment is optimized to divide the vertical flue 114 into an upper space and a lower space, wherein the main economizer 141 is located in the lower space, and the bypass economizer 142 and the low temperature reheater 151 are located in the upper space, and the upper portion The space and the lower space are connected by the expansion joint 117. In this embodiment, the vertical flue 114 is divided into an upper space and a lower space by the above-mentioned double flue and single flue. That is, the double flue corresponds to the upper space, and the main economizer 141 is located below the double flue, which is a single flue, corresponding to the lower space, for which a non-metallic expansion joint 117 is used at the junction of the double flue and the single flue. Connected, which absorbs expansion and reduces leakage.

Further, the structure of the superheating unit 13 is refined, including the screen superheater assembly 131, the convection low temperature superheater 132, and the convection high temperature superheater 133, which are sequentially connected, that is, the steam sequentially passes through the screen superheater assembly 131. The low temperature superheater 132 and the high temperature superheater 133, and the vapor outlet of the drum 12 communicates with the screen superheater assembly 131, and the high temperature superheater 133 communicates with the inlet of the high pressure cylinder 211 of the steam turbine 21. In addition, the heat absorption ratio of the screen type superheater unit 131 is 6.5% to 7.6%, the heat absorption ratio of the low temperature superheater 132 is 9.4% to 10.8%, and the heat absorption ratio of the high temperature superheater 133 is 9.9% to 10.9%. The heat absorption ratio mainly refers to the ratio of the corresponding components in the furnace body 11 to the total heat absorption. For example, the heat absorption ratio of the screen type superheater assembly 131 is 6.5% to 7.6%, and the influencing factors of the heat absorption ratio are various, mainly It is determined according to the heating surface of the corresponding component, and of course, it is related to the position of the corresponding component in the furnace body, mainly the temperature of the flue gas is higher near the position of the combustion chamber 111, thereby facilitating the improvement of the endothermic ratio, and adopting this structure. The form of the superheating unit 13 can make the superheated steam after heating to be 13.7 MPa/566 ° C, forming an ultra-high temperature ultra-high voltage power generation system, thereby solving the problem that the heating surface of the superheater of the gas boiler 1 is overheated, and stabilizing the steam and water parameters, especially The gas boiler 1 stabilizes the steam and water parameters when the load is pulled up or the high load fluctuates, which not only ensures the safety of the gas boiler 1, but also avoids the risk of the superheater being easy to squirt, and improves the low calorific value gas ultra high temperature and ultra high pressure. The overall thermal efficiency of the system; or in other embodiments, the endothermic ratio of the screen superheater assembly 131 is 6.0% to 7.0%, and the endothermic ratio of the low temperature superheater 132 is 9.0% to 10.5%, and the high temperature superheater 133 The heat absorption ratio is 9.5% to 10.5%, and the superheating unit 13 adopting such a structure can make the superheated steam after heating to be 13.7 MPa/540 ° C to form a high-temperature ultra-high voltage power generation system; or, the screen type superheater assembly 131 The endothermic ratio is 7.8% to 8.9%, the endothermic ratio of the low temperature superheater 132 is 10.8% to 12.2%, and the endothermic ratio of the high temperature superheater 133 is 11.4% to 12.3%, and the superheating unit 13 adopting such a structure is adopted. The heated superheated steam can be made 16.7 MPa/600 ° C to form an ultra-high temperature subcritical power generation system; or the screen type superheater assembly 131 has an endothermic ratio of 7.5% to 8.5%, and the low temperature superheater 132 has an endothermic ratio of 10.3% to 11.8%, the heat absorption ratio of the high temperature superheater 133 is 10.9% to 11.9%, and the superheating unit 13 adopting this structure can make the superheated steam after heating to be 16.7 MPa/566 ° C to form an ultrahigh temperature subcritical Power generation system; or, screen type The heat absorption ratio of the device assembly 131 is 6.8% to 7.8%, the heat absorption ratio of the low temperature superheater 132 is 9.9% to 11.3%, and the heat absorption ratio of the high temperature superheater 133 is 10.5% to 11.5%, and this structural form is adopted. The superheating unit 13 can make the superheated steam after heating 600 ° C / 11.5 MPa to form an ultra-high temperature ultra-high voltage power generation system; or, the heat absorption ratio of the screen type superheater assembly 131 is 5.2% - 6.1%, the low temperature superheater 132 The heat absorption ratio is 8.2% to 9.7%, and the heat absorption ratio of the high temperature superheater 133 is 8.9% to 9.5%, and the superheating unit 13 adopting such a structure can make the superheated steam after heating 9.8 MPa/540 °C. Form a high temperature and high voltage power generation system. In this embodiment, the screen superheater assembly 131 is a semi-radiant superheater, and the low temperature superheater 132 and the high temperature superheater 133 are both convective superheaters, that is, the superheating unit 13 provided by the present invention is combined with radiation and convection. In the manner of multiple cross-mixing, the screen superheater assembly 131 is located directly above the combustion chamber 111, and the high-temperature flue gas generated after the low-calorific value gas combustion first flows to the screen superheater assembly 131, and the high-temperature superheater 133 And low The temperature superheaters 132 are sequentially disposed along the flow direction of the flue gas, and the steam heated in the wall tube and the steam heated in the superheater partition wall 16 are both introduced into the screen superheater assembly 131 and heated by the screen superheater assembly 131. The heat is introduced into the low temperature superheater 132, and finally heated into the high temperature superheater 133, so that the superheated steam can be obtained for the work done in the steam turbine 21. Generally, the furnace body 11 is bent and extended into the horizontal flue 113 at the outlet of the combustion chamber 111 to form a flame angle 118. The flame angle 118 includes a first inclined section and a second inclined section, wherein the first inclined section is upward. The direction extends obliquely into the horizontal flue 113, and the second inclined section extends obliquely upward from the first inclined section toward the vertical flue 114, so that the first inclined section can be formed to first narrow the combustion chamber 111 to the horizontal The caliber of the flue 113, and then through the second inclined section, causes the diameter of the horizontal flue 113 to be tapered along the flow direction of the flue gas, which can effectively improve the aerodynamic field in the horizontal flue 113. The screen superheater assembly 131 includes a front screen superheater 134 and a rear screen superheater 135, both of which are located in the space of the horizontal flue 113 corresponding to the flame angle 118, and the front screen superheater 134 and the steam of the drum 12 The body outlet is in communication, specifically communicating with the outlet of the wall tube and the outlet of the superheater partition 16 such that both of the steam in both can flow into the front screen superheater 134, while the rear screen superheater 135 is connected to the front screen superheater. 134 and the low temperature superheater 132, the steam heated in the front screen superheater 134 is first heated into the rear screen superheater 135 and then into the low temperature superheater 132. The front screen superheater 134, the rear screen superheater 135, the low temperature superheater 132 and the high temperature superheater 133 are suspended by a boom on a top steel frame and are made of 12Cr1MoVG material, and some steel sections are made of steel grinding 102 alloy. steel.

Further, the superheater unit 13 is further provided with a steam temperature adjusting structure. For example, a first-stage water spray structure is arranged on the flow path between the front screen superheater 134 and the rear screen superheater 135, and the first-stage water spray structure adopts water spray desuperheating. The device cools the steam spray in the flow path between the front screen superheater 134 and the rear screen superheater 135, which is a coarse adjustment, and can initially adjust the temperature of the steam. The steam temperature regulating structure further comprises a two-stage water spray structure, which is installed on the high temperature superheater 133. The high temperature superheater 133 comprises two cold sections and one hot section, and the hot section is located between the two cold sections, which can be in front The secondary spray structure is arranged on the flow path between a cold section and a hot section, where the adjustment is fine adjustment, and a regulating valve and a shut-off valve can be arranged on the flow path, so that the relative temperature adjustment of the steam temperature in the flow path can be achieved. . In this regard, through the joint adjustment of the first-stage water spray structure and the secondary spray structure, the temperature of the superheated steam under the rated load of the gas boiler 1 can be ensured, and the water for the first-stage water spray structure and the secondary spray structure can be used. The water after deoxidation extracted from the feed water pump 27. Usually, a steam header 136 is disposed on the flow path between the superheating unit 13 and the steam turbine 21, and the superheated steam heated by the high temperature superheater 133 first enters the steam header 136 for buffering, and then is introduced into the high pressure of the steam turbine 21. The cylinder 211 is rushed to work.

Further, an air preheater 17 is further disposed at the bottom of the vertical flue 114, and the air replenished into the combustion chamber 111 first enters the air preheater 17, and the flue gas flow in the vertical flue 114 is advanced to the air preheating. The heater 17 can heat the air therein to increase the utilization of the heat of the flue gas. Of course, the flue gas is not mixed with the air in the air preheater 17, and the two are non-contact heating. The air preheater 17 adopts a vertical tube box structure, single-stage single-stroke arrangement, and the tube of the air preheater 17 is a thin-walled spiral groove tube, the longitudinal direction of the flue gas tube is flushed, and the air tube is laterally flushed to prevent the air preheater. The vibration of 17 is equipped with a shock-proof partition in the pipe box.

Referring to FIG. 1 and FIG. 2, in summary, the power generation system with the above structure can generate heat generated after combustion of low calorific value gas. The amount of power is used for power generation. The specific steps are as follows:

The low calorific value gas is sent from the gas pipe through the double swirl burner 112 into the combustion chamber 111 of the gas boiler 1 for combustion, and heat is generated by combustion to heat the heated surfaces;

The water in the drum 12 flows out through the liquid outlet, and two flow paths are formed, wherein the first-class road is sent to the water-cooling wall 115 of the furnace body 11 through the pipeline, and the other flow path is sent to the evaporation convection pipe screen 116 through the pipeline, and the water is in the liquid. The water wall 115 and the evaporating convection pipe screen 116 are heated, phased into a soda water mixture, and sent back to the drum 12 through a pipe;

The steam-water mixture is separated into steam and water in the drum 12, and the separated saturated steam is sent to the ceiling pipe through the pipeline. In the ceiling pipe, the steam is divided into four roads, and two of the roads (the front left side pack and the front right side pack) are heated. Enter the wall pipe, the other two (the rear left package and the rear right package) are heated and enter the superheater partition wall 16, and the steam coming out from the wall pipe and the superheater partition wall 16 enters the front screen superheater 134;

After the front screen superheater 134 is heated, it enters the rear screen superheater 135, and the temperature of the steam is adjusted by the first stage water spray structure between the front screen superheater 134 and the rear screen superheater 135, after the rear screen superheater 135 is heated, The low temperature superheater 132 is heated, and then heated into the high temperature superheater 133, and is again tempered by the secondary spray structure between the cold section and the hot section of the high temperature superheater 133, and the superheated steam after the secondary spray water temperature adjustment Entering the steam header 136;

After the superheated steam is buffered in the steam collecting header, it is sent to the high pressure cylinder 211 of the steam turbine 21 through the pipeline, and the steam is used to drive the blades of the steam turbine 21, and the steam turbine 21 drives the generator 22 to generate electricity, and the steam temperature and pressure are reduced after the work is performed;

The steam from the high pressure cylinder 211 enters the low temperature reheater 151, and then enters the high temperature reheater 152 to be reheated into superheated steam, and the superheated steam is introduced into the low pressure cylinder 212 of the steam turbine 21, and after the work is performed, the steam temperature and pressure are again reduce;

The exhausted steam from the low pressure cylinder 212 of the steam turbine 21 enters the condenser 23 for condensation, is condensed into a water liquid of about 40 ° C in the condenser 23, and is then driven into the low pressure heater 25 by the condensate water pump 24, at the low pressure heater 25 The medium is heated by the low pressure steam extraction of the steam turbine;

The water from the low-pressure heater 25 enters the deaerator 26, and after the deaerator 26 performs deaeration, the feed water pump 27 is driven into the high-pressure heater 28, and is heated by the high-pressure extraction steam of the turbine in the high-pressure heater 28, after which Entering the main economizer 141;

After the main economizer 141 is heated by the flue gas at the end of the vertical flue 114, the water liquid enters the bypass economizer 142, is further heated, and is recycled into the drum 12, and the water in the above steps is sequentially repeated. With steam steps. In addition, a branch is also provided at the outlet of the main economizer 141, and is sent to the drum 12 as washing water when necessary, for cleaning of the drum 12.

The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., which are included in the spirit and scope of the present invention, should be included in the present invention. Within the scope of protection.

Claims (18)

A low calorific value gas power generation system comprising a gas boiler and a generator set, the generator set including a steam turbine connected to the gas boiler pipe and a generator driven by the steam turbine, wherein the gas boiler includes a built-in a furnace body of the combustion chamber and a drum that can be separated by steam and water, the furnace body comprising a horizontal flue above the combustion chamber and a vertical flue communicating with the horizontal flue, the furnace body is provided with water cooling a wall, at least one port of the water wall is in communication with a liquid outlet of the drum, at least one port is in communication with a vapor inlet of the drum, and superheat is disposed in the horizontal flue and the vertical flue, respectively a unit and an economizer unit, the superheat unit is connected to a vapor outlet of the drum and a high pressure cylinder inlet of the steam turbine, and the economizer unit is connected to a steam outlet of the steam turbine and a liquid of the drum An inlet, and a condenser is disposed on the pipeline between the economizer unit and the steam turbine. A low calorific value gas power generation system according to claim 1, wherein a reheater unit is further disposed in said furnace body, said reheater unit being connected to said low pressure cylinder inlet of said steam turbine and said high pressure of said steam turbine Cylinder outlet. A low calorific value gas power generation system according to claim 2, wherein said reheater unit comprises a low temperature reheater disposed in said vertical flue, said high pressure cylinder outlet of said steam turbine being connected to said Low temperature reheater. A low calorific value gas power generation system according to claim 3, wherein said reheater unit further comprises a high temperature reheater installed in said horizontal flue, said high temperature reheater being connected to said low temperature The heat exchanger is connected to the low pressure cylinder of the steam turbine. A low calorific value gas power generation system according to claim 3, wherein said economizer unit comprises a main economizer installed at the bottom of said vertical flue and above said main economizer and a bypass economizer in communication with the main economizer, the condenser outlet is connected to the main economizer, the bypass economizer is also connected to a liquid inlet of the drum, and the side The road economizer is arranged side by side with the low temperature reheater, and is separated by a superheater partition wall. A low calorific value gas power generation system according to claim 5, wherein said vertical flue comprises an upper space and a lower space, said main economizer being located in said lower space, said bypass economizer The low temperature reheater is located in the upper space, and the upper space and the lower space communicate through an expansion joint. The low calorific value gas power generation system according to claim 1, wherein said superheating unit comprises a screen type superheater unit, a convection type low temperature superheater, and a convection type high temperature superheater, wherein the three are sequentially connected, and said A vapor outlet of the drum communicates with the screen superheater assembly, the high temperature superheater being in communication with the high pressure cylinder inlet of the steam turbine. A low calorific value gas power generation system according to claim 7 wherein said screen superheater assembly includes a front screen superheater in communication with said vapor outlet of said drum and said front screen superheater and said The rear screen superheater of the low temperature superheater is provided with a first stage water spray structure on the flow path of the front screen superheater and the rear screen superheater. The low calorific value gas power generation system according to claim 7, wherein said high temperature superheater comprises two cold sections and a hot section, the hot section is located between the two cold sections, and a secondary water spray structure is disposed on the flow path between the cold section and the hot section. The low calorific value gas power generation system according to claim 1, wherein the furnace body is bent and extended into the horizontal flue at an exit of the combustion chamber to form a flame angle, wherein the flame angle includes a first inclined section that extends obliquely toward the horizontal flue in an upward direction and a second inclined section that is inclined upward by the first inclined section in a direction toward the vertical flue. The low calorific value gas power generation system according to claim 7, wherein the superheating unit is heated to form a high temperature and high pressure superheated steam of 9.8 MPa/540 ° C, and the heat absorption ratio of the screen type superheater assembly is 5.2%. 6.1%, the convection type low temperature superheater has an endothermic ratio of 8.2% to 9.7%, and the convection type high temperature superheater has an endothermic ratio of 8.9% to 9.5%; Alternatively, the superheater unit is heated to form a high temperature ultrahigh pressure superheated steam of 13.7 MPa/540 ° C, and the endothermic ratio of the screen type superheater assembly is 6.0% to 7.0%, and the heat absorption ratio of the convection type low temperature superheater Between 9.0% and 10.5%, the convection type high temperature superheater has an endothermic ratio of 9.5% to 10.5%; Alternatively, the superheater unit is heated to form an ultra-high temperature ultra-high pressure superheated steam of 13.7 MPa/566 ° C, and the heat absorption ratio of the screen type superheater assembly is 6.5% to 7.6%, and the heat absorption of the convection type low temperature superheater The ratio is 9.4% to 10.8%, and the endothermic high temperature superheater has an endothermic ratio of 9.9% to 10.9%; Alternatively, the superheater unit is heated to form ultra-high temperature ultra-high pressure superheated steam of 13.7 MPa/600 ° C, and the heat absorption ratio of the screen type superheater assembly is 6.8% to 7.8%, and the convection type low temperature superheater is sucked. The heat ratio is 9.9% to 11.3%, and the heat absorption ratio of the convection type high temperature superheater is 10.5% to 11.5%; Alternatively, the superheater unit is heated to form an ultra-high temperature subcritical superheated steam of 16.7 MPa/566 ° C, and the endothermic ratio of the screen superheater assembly is 7.5% to 8.5%, and the endothermic low temperature superheater absorbs heat. The ratio is 10.3% to 11.8%, and the endothermic high temperature superheater has an endothermic ratio of 10.9% to 11.9%; Alternatively, the superheater unit is heated to form an ultra-high temperature subcritical superheated steam of 16.7 MPa/600 ° C, and the endothermic ratio of the screen superheater assembly is 7.8% to 8.9%, and the convection type low temperature superheater is sucked. The heat ratio is 10.8% to 12.2%, and the heat absorption ratio of the convection type high temperature superheater is 11.4% to 12.3%. A low calorific value gas power generation method, comprising the steps of: The low calorific value gas is sent from the gas pipeline to the combustion chamber of the gas boiler through the burner for combustion, and heat is generated by combustion to heat the heated surfaces; The water in a drum is discharged through the liquid outlet, and is sent to the water wall of the furnace body of the gas boiler through a pipe, and the water is heated in the water wall, and the phase is changed into a steam-water mixture, and is sent back through the pipeline. Pot drum The steam-water mixture is subjected to steam-water separation in the drum, and the separated saturated steam is sent to the ceiling pipe through the pipeline, and the saturated steam is introduced into the superheating unit in the furnace body through the ceiling pipe to continue heating to superheated steam; The superheated steam is sent to the high pressure cylinder of the steam turbine through the pipeline, and the steam rushes the blades of the steam turbine, and the steam turbine drives the generator to generate electricity, and the steam temperature and pressure are reduced after the work is performed; The steam coming out of the high-pressure cylinder enters a low-temperature reheater, and then enters a high-temperature reheater to be heated again to superheated steam, and the superheated steam is introduced into the low-pressure cylinder of the steam turbine, and after the work is performed, the steam temperature and The pressure is lowered again; The spent steam from the low pressure cylinder of the steam turbine enters the condenser for condensation, is condensed into water in the condenser, and then the water is pumped into the low pressure heater by the condensate pump, where it is Low-pressure extraction steam heating of the turbine; The water from the low-pressure heater enters the deaerator, and after the deaerator is deaerated, the high-pressure heater is driven by the feed water pump, and is heated by the high-pressure extraction steam of the steam turbine in the high-pressure heater, after which Enter the main economizer; After the main economizer is heated by the flue gas, the water liquid enters the bypass economizer, is further heated, and is re-introduced into the drum for recycling. The low calorific value gas power generation method according to claim 12, wherein the superheating unit comprises a screen type superheater unit, a convection type low temperature superheater, and a convection type high temperature superheater, wherein the three are sequentially connected to each other. The tube first introduces saturated steam into the screen superheater assembly for heating, and then sequentially enters the low temperature superheater and the high temperature superheater to heat to superheated steam. The low calorific value gas power generation method according to claim 13, wherein said screen superheater assembly comprises a front screen superheater and a rear screen superheater, and said front screen superheater and said rear screen superheater The flow path is provided with a first-stage water spray structure, and the ceiling pipe first introduces saturated steam into the front screen superheater for heating, and then uses the first-stage water spray structure to cool the heated saturated steam, and saturates after cooling. The steam enters the rear screen superheater to continue heating, and the saturated steam heated by the rear screen superheater is introduced into the low temperature superheater for heating. The low calorific value gas power generation method according to claim 12, wherein the superheated steam generated by the heating by the superheating unit first enters a steam collecting box, and the high pressure is introduced into the steam turbine by the steam collecting box. Inside the tank. The low calorific value gas power generation method according to claim 12, wherein the bypass economizer is disposed side by side with the low temperature reheater, and is separated by a superheater partition wall, through the ceiling tube The heated saturated steam is divided into four paths, wherein two of them enter the wall-walled tube for heating, and the heated saturated steam enters the superheating unit to continue heating; the other two channels enter the superheater partition wall for heating, and the heated after saturation Steam also enters the superheater unit to continue heating. The low calorific value gas power generation method according to claim 12, wherein the air entering the combustion combustion first enters the air preheater, and the air preheater uses a smoke pair generated by low calorific value gas combustion The incoming air is preheated. The low calorific value gas power generation method according to claim 12, wherein the water liquid heated by the main economizer cleans the drum through a road.

Images