CN209876968U - Waste heat utilization system for starting boiler of gas turbine power plant - Google Patents

Abstract

The utility model discloses a gas turbine power plant starting boiler waste heat utilization system, wherein a starting boiler smoke exhaust mechanism is internally provided with a superheater, a boiler economizer and a waste heat economizer which are sequentially arranged along the smoke exhaust direction; a heat medium water circulation inlet of the heating water tank is communicated with one end of the first heat medium water heat exchange channel; two ends of a second heat medium water heat exchange channel of the natural gas heating device are communicated with a heat medium water circulation outlet of the heating water tank and the first heat medium water heat exchange channel respectively. By the aid of the optimally designed gas turbine power plant starting boiler waste heat utilization system, the waste heat of the tail flue of the starting boiler is utilized to heat the heating medium water required by the natural gas heating device, and a small amount of starting boiler superheated steam is supplemented, so that the gas turbine system is guaranteed to operate safely and efficiently, and energy consumption is reduced; the use of superheated steam of a high-grade heat energy starting boiler is reduced, and the gradient utilization of energy is realized; and the adjustment mode increases the adjustment means of natural gas heating and widens the adjustment range.

Description

A waste heat utilization system for starting boilers in gas-fired power plants

technical field

The utility model relates to the field of boiler waste heat utilization, in particular to a boiler waste heat utilization system of a gas-fired power plant.

Background technique

The natural gas temperature has a great influence on the combustion of the gas turbine and the dynamic characteristics of the combustion chamber. At the same time, the natural gas temperature is also used for fuel calculation, fuel flow and fuel analysis. It is very important to ensure a reasonable natural gas inlet temperature. The minimum natural gas temperature is higher than the dew point of the hydrocarbons to avoid liquefaction of the hydrocarbons. The gas fuel supply temperature shall be kept at least 28°C above the dew point of the hydrocarbons, and there shall be no liquid hydrocarbons and water in the gaseous fuel at any time. In order to meet the requirements of natural gas temperature, there are two main types of natural gas temperature control during the ignition of the unit to full speed no-load. One is heating by electric heaters, and the other is heating heat medium water by mixing the superheated steam of the startup boiler. It is then realized by heat exchange through a gas-water heat exchanger. During the normal load phase of the unit, the natural gas can be heated by the waste heat of the flue gas at the tail of the waste heat boiler. Electric heaters often use temperature difference control, that is, the difference between the temperature of the natural gas at the outlet of the heater and the temperature at the inlet is less than a certain value, the electric heater will always start, and stop working when the difference reaches a certain value. In addition, when the temperature of the natural gas at the outlet of the heater is too high , the heater automatically trips to prevent local overheating and carbonization of the natural gas inside the heater.

In the existing natural gas heating system of gas turbine power plants, electric heating is often used to heat natural gas during the start-up stage of the unit, which consumes a lot of energy and easily causes local overheating and carbonization of natural gas; while gas turbine power plants equipped with startup boilers often use startup boilers The generated superheated steam heats the natural gas through heat exchange, and the natural gas usually only needs to be heated to 40-60 °C.

Utility model content

In order to solve the technical problems existing in the background technology, the utility model proposes a waste heat utilization system for starting a boiler of a gas-fired power plant.

The utility model proposes a waste heat utilization system for starting a boiler in a gas-fired power plant, comprising: starting a boiler hearth and a tail flue, a heating water tank, and a natural gas heating device;

A smoke exhaust channel is arranged in the furnace hearth and the tail flue of the startup boiler, and a superheater, a boiler economizer and a waste heat economizer are arranged in sequence along the smoke exhaust direction in the smoke exhaust channel, and the waste heat economizer is provided with a There is a first heat medium water heat exchange channel;

The heating water tank is provided with a heat medium water circulation inlet and a heat medium water circulation outlet, and the heat medium water circulation inlet is communicated with one end of the first heat medium water heat exchange channel through a pipeline;

The natural gas heating device is provided with a second heat medium water heat exchange channel, one end of the second heat medium water heat exchange channel is communicated with the heat medium water circulation outlet of the heating water tank, and the other end is exchanged with the first heat medium water through a pipeline. One end of the hot aisle away from the heating water tank is communicated.

Preferably, a booster pump is provided on the pipeline between the heat medium water circulation inlet and the first heat medium water heat exchange channel.

Preferably, the heating water tank is also provided with a superheated steam inlet.

Preferably, a shower head is provided in the heating water tank, and the shower head communicates with the heating medium water circulation inlet.

Preferably, a water replenishment port is provided on the pipeline between the second heat medium water heat exchange channel and the first heat medium water heat exchange channel.

Preferably, the structure of the waste heat economizer adopts the spiral fin type, the light pipe type or the H fin type.

Preferably, a smoke exhaust chimney is provided at the discharge end of the smoke exhaust passage.

In the utility model, the proposed gas-fired power plant starts the boiler waste heat utilization system, and the smoke exhaust passages of the boiler hearth and the tail flue are provided with superheaters, boiler economizers and waste heat economizers arranged in sequence along the smoke exhaust direction. The waste heat economizer is provided with a first heat medium water heat exchange channel; the heat medium water circulation inlet of the heating water tank is connected to one end of the first heat medium water heat exchange channel; the second heat medium water heat exchange channel of the natural gas heating device The two ends are respectively communicated with the heat medium water circulation outlet of the heating water tank and the first heat medium water heat exchange channel. Through the above optimized design of the boiler waste heat utilization system, the waste heat of the boiler tail flue is used to heat the heat medium water required for the natural gas heating device, and supplemented by a small amount of boiler superheated steam to heat the natural gas to a specific temperature. It ensures the safe and efficient operation of the gas turbine system and saves energy consumption; reduces the use of superheated steam for starting boilers with high-grade thermal energy, and realizes the cascade utilization of energy; and this adjustment method increases the adjustment means for natural gas heating And widen the adjustment range.

Description of drawings

FIG. 1 is a schematic structural diagram of a waste heat utilization system for starting a boiler of a gas-fired power plant proposed by the utility model.

Detailed ways

As shown in FIG. 1 , FIG. 1 is a schematic structural diagram of a waste heat utilization system for starting a boiler of a gas-fired power plant proposed by the present invention.

Referring to FIG. 1 , a waste heat utilization system for starting boilers in a gas-fired power plant proposed by the present utility model includes: starting a boiler smoke exhaust mechanism 13 , a heating water tank 8 , and a natural gas heating device 15 ;

A smoke exhaust channel 12 is provided in the start-up boiler smoke exhaust mechanism 13. The smoke exhaust channel 12 is provided with a superheater 11, a boiler economizer 5, and a waste heat economizer 4, which are arranged in sequence along the smoke exhaust direction. A first heat medium water heat exchange channel is arranged in the coal collector 4;

The heating water tank 8 is provided with a heat medium water circulation inlet and a heat medium water circulation outlet, and the heat medium water circulation inlet is communicated with one end of the first heat medium water heat exchange channel through a pipeline;

The natural gas heating device 15 is provided with a second heat medium water heat exchange channel, one end of the second heat medium water heat exchange channel is connected with the heat medium water circulation outlet of the heating water tank 8, and the other end is connected to the first heat medium water through a pipeline. One end of the heat exchange channel away from the heating water tank 8 is communicated.

In the specific working process of the boiler waste heat utilization system of the gas turbine power plant of this embodiment, the flue gas formed when the boiler is started to burn enters the smoke exhaust mechanism, and flows through the exhaust gas channel after heat exchange between the superheater and the boiler economizer. The waste heat economizer is further cooled by the waste heat economizer and then discharged into the atmosphere; the natural gas heating device uses the heat medium water to heat the natural gas through the gas-water heat exchange, and the heat medium water after heating the natural gas flows back into the exhaust channel through the natural gas heating device In the waste heat economizer, the heat medium water is reheated by the flue gas in the waste heat economizer, and then enters the heating water tank through the waste heat economizer through the heat medium water circulation inlet for mixing, and the mixed heat medium water enters the natural gas heating device for heating Natural gas, completes a cycle.

In the present embodiment, the proposed gas-fired power plant starts the boiler waste heat utilization system, and the smoke exhaust passage of the boiler smoke exhaust mechanism is provided with a superheater, a boiler economizer, and a waste heat economizer arranged in sequence along the smoke exhaust direction. The waste heat economizer is provided with a first heat medium water heat exchange channel; the heat medium water circulation inlet of the heating water tank is connected to one end of the first heat medium water heat exchange channel; the second heat medium water heat exchange channel of the natural gas heating device has two channels. The ends are respectively communicated with the heat medium water circulation outlet of the heating water tank and the first heat medium water heat exchange channel. Through the above optimally designed gas turbine power plant startup boiler waste heat utilization system, the waste heat from the boiler tail flue is used to heat the heat medium water required for the natural gas heating device, and supplemented by a small amount of boiler superheated steam to heat the natural gas to a specific temperature. It ensures the safe and efficient operation of the gas turbine system and saves energy consumption; reduces the use of superheated steam for starting boilers with high-grade thermal energy, and realizes the cascade utilization of energy; and this adjustment method increases the adjustment means for natural gas heating And widen the adjustment range.

In a specific embodiment, a booster pump 9 is provided on the pipeline between the heat medium water circulation inlet and the first heat medium water heat exchange channel. Pressurized water.

In other specific embodiments, the heating water tank 8 is also provided with a superheated steam inlet 7; when the temperature of the heat medium water cannot be sufficient to heat the natural gas to a specified temperature, a small amount of superheated steam for starting the boiler is introduced into the heating water tank through the superheated steam inlet, The superheated steam can enter the heating water tank and mix with the heat medium water to meet the heat demand and improve the utilization rate of waste heat.

In order to improve, the heating water tank 8 is provided with a shower head, and the shower head is communicated with the heat medium water circulation inlet; thus, the mixing of the heat medium water in the heating water tank is enhanced.

In order to supplement the loss of heat medium water in the circulation, the pipeline between the second heat medium water heat exchange channel and the first heat medium water heat exchange channel is provided with a water replenishing port 2, and the water supply port 2 is connected to the circulating water channel through the water replenishing port. Hydrate.

In the specific selection method of the waste heat economizer, the structure of the waste heat economizer 4 adopts the spiral fin type, the light tube type or the H fin type.

In the specific design of the smoke exhaust mechanism, the exhaust end of the smoke exhaust passage 12 is provided with a smoke exhaust chimney 3 , through which the exhaust gas cooled by heat exchange is easily discharged.

The above description is only a preferred embodiment of the present invention, but the protection scope of the present invention is not limited to this. Equivalent replacement or modification of the new technical solution and its utility model concept shall be included within the protection scope of the present utility model.

Claims (7)

1. A waste heat utilization system for starting a boiler of a gas-fired power plant, characterized in that, comprising: starting a boiler smoke exhaust mechanism (13), a heating water tank (8), and a natural gas heating device (15); A smoke exhaust channel (12) is provided in the start-up boiler smoke exhaust mechanism (13), and the smoke exhaust channel (12) is provided with a superheater (11), a boiler economizer (5), a boiler economizer (5), a waste heat economizer (4), wherein the waste heat economizer (4) is provided with a first heat medium water heat exchange channel; The heating water tank (8) is provided with a heat medium water circulation inlet and a heat medium water circulation outlet, and the heat medium water circulation inlet is communicated with one end of the first heat medium water heat exchange channel through a pipeline; The natural gas heating device (15) is provided with a second heat medium water heat exchange channel, one end of the second heat medium water heat exchange channel is communicated with the heat medium water circulation outlet of the heating water tank (8), and the other end is connected to the heat medium water circulation outlet through a pipeline One end of the first heat medium water heat exchange channel away from the heating water tank (8) is communicated. 2. The waste heat utilization system for starting a boiler of a gas-fired power plant according to claim 1, wherein a booster pump (9) is provided on the pipeline between the heat medium water circulation inlet and the first heat medium water heat exchange channel . 3 . The waste heat utilization system for starting a boiler of a gas-fired power plant according to claim 1 , wherein the heating water tank ( 8 ) is further provided with a superheated steam inlet ( 7 ). 4 . 4 . The waste heat utilization system for starting a boiler of a gas-fired power plant according to claim 1 or 3 , wherein the heating water tank ( 8 ) is provided with a sprinkler head, and the sprinkler head communicates with the heat medium water circulation inlet. 5 . 5 . The waste heat utilization system for starting a boiler of a gas-fired power plant according to claim 1 , wherein the pipeline between the second heat medium water heat exchange channel and the first heat medium water heat exchange channel is provided with 5 . Water filling port (2). 6 . The waste heat utilization system for start-up boilers of a gas-fired power plant according to claim 1 , wherein the structure of the waste heat economizer ( 4 ) adopts a spiral fin type, a light tube type or an H fin type. 7 . 7 . The waste heat utilization system for starting a boiler of a gas-fired power plant according to claim 1 , wherein a smoke exhaust chimney ( 3 ) is provided at the discharge end of the smoke exhaust passage ( 12 ). 8 .