JP-7855923-B2 - Exhaust gas boiler system

JP7855923B2JP 7855923 B2JP7855923 B2JP 7855923B2JP-7855923-B2

Inventors

福田尚史
石崎信行

Assignees

三浦工業株式会社

Dates

Publication Date: 20260511
Application Date: 20220530

Claims (3)

A first evaporator that evaporates the makeup water by exchanging heat with the exhaust gas, A second evaporator exchanges heat with the exhaust gas that has passed through the first evaporator to evaporate the makeup water, An economizer that heats the makeup water supplied to the first and second evaporators by exchanging heat with the exhaust gas that has passed through the second evaporator, A steam compressor , powered by electricity, compresses the steam generated in the second evaporator, A steam header into which the steam generated in the first evaporator and the steam compressed in the steam compressor are introduced, Equipped with, The vapor pressure of the second evaporator is between 0.05 MPa and 0.2 MPa. Exhaust gas boiler system.
The exhaust gas temperature is between 250°C and 320°C. The vapor pressure of the first evaporator is between 0.5 MPa and 1.0 MPa. The exhaust gas boiler system according to claim 1.
The exhaust gas boiler system according to claim 1 or 2, wherein the steam compressor is a water-injection type steam compressor equipped with a water supply means for injecting water into the space in which steam is compressed.

Description

This invention relates to an exhaust gas boiler system. For example, gas engines that drive generators emit high-temperature exhaust gas, so exhaust gas boilers are used to recover heat from the exhaust gas and generate steam. To increase the amount of heat that can be recovered from the exhaust gas, exhaust gas boilers equipped with multiple evaporators (boilers) arranged in a row from the upstream to the downstream side of the exhaust gas flow path are also known. In such exhaust gas boilers, higher pressure steam can be obtained further upstream. Since steam that is too low in pressure cannot be effectively utilized, exhaust gas boilers also need to generate steam with a certain minimum pressure. For example, Patent Document 1 proposes obtaining usable steam by mixing high-pressure steam generated in an upstream evaporator with low-pressure steam generated in a downstream evaporator using an ejector. Patent No. 5359540 This is a schematic diagram showing the configuration of an exhaust gas boiler system according to one embodiment of the present invention. The embodiments of the present invention will be described below with reference to the drawings. Figure 1 is a schematic diagram showing the configuration of an exhaust gas boiler system 1 according to one embodiment of the present invention. The exhaust gas boiler system 1 recovers heat from exhaust gas emitted by a gas engine (not shown) and generates steam. The exhaust gas boiler system 1 includes an exhaust gas chamber 10 for guiding the exhaust gas, a first evaporator 20, a second evaporator 30, and an economizer 40 arranged sequentially from upstream within the exhaust gas chamber 10, a steam compressor 50 for compressing the steam generated in the second evaporator 30, and a steam header 60 into which the steam generated in the first evaporator 20 and the steam compressed by the steam compressor 50 are introduced. The exhaust gas chamber 10 guides the exhaust gas so that it passes through the first evaporator 20, the second evaporator 30, and the economizer 40 in that order before being discharged to the outside through a chimney (not shown). The lower limit of the exhaust gas temperature introduced into the exhaust gas chamber 10 is preferably 250°C, and more preferably 270°C. On the other hand, the upper limit of the exhaust gas temperature introduced into the exhaust gas chamber 10 is preferably 320°C, and more preferably 300°C. If the temperature of the exhaust gas introduced into the exhaust gas chamber 10 is above the lower limit, heat can be effectively recovered by generating steam from the exhaust gas. Furthermore, if the temperature of the exhaust gas introduced into the exhaust gas chamber 10 is below the upper limit, a higher heat recovery rate can be achieved compared to conventional single-stage exhaust gas boilers, where the decrease in heat recovery rate is significant with decreasing exhaust gas temperature. In other words, the temperature range is particularly advantageous for the exhaust gas boiler system 1 compared to conventional exhaust gas boilers. The first evaporator 20 evaporates the makeup water by exchanging heat with the exhaust gas. The first evaporator 20 can be a once-through boiler comprising: a lower header 21 for storing makeup water; multiple water tubes 22 extending from the lower header 21, heated by the exhaust gas, and used to evaporate the makeup water inside; an upper header 23 for collecting steam generated in the water tubes 22; a steam-water separator 24 for separating water droplets contained in the steam flowing out of the upper header 23; and a feed valve 25 for adjusting the amount of makeup water supplied to the lower header 21 to maintain the water level in the water tubes 22 within a certain range. The lower limit of the vapor pressure (gauge pressure) of the first evaporator 20 is preferably 0.5 MPa, and more preferably 0.6 MPa. On the other hand, the upper limit of the vapor pressure of the first evaporator 20 is preferably 1.0 MPa, and more preferably 0.9 MPa. By setting the vapor pressure of the first evaporator 20 above the lower limit, the steam generated in the first evaporator 20 can be used in general demand facilities. In addition, by setting the vapor pressure of the first evaporator 20 above the lower limit, the exhaust gas temperature in the first evaporator 20 can be prevented from becoming too low, allowing for efficient heat recovery in the second evaporator 30 and improving the overall thermal efficiency of the exhaust gas boiler system 1. Furthermore, by setting the vapor pressure of the first evaporator 20 below the upper limit, the amount of heat recovered in the first evaporator 20 can be secured, and equipment costs can be prevented from unnecessarily increasing. The second evaporator 30 evaporates the makeup water by exchanging heat with the exhaust gas that has passed through the first evaporator 20. The second evaporator 30 can be a once-through boiler comprising: a low