JPH04347308A - Exhaust heat recovery device - Google Patents

Abstract

PURPOSE:To improve efficiency in a gas turbine/steam turbine combined power generating plant which uses reformed fuel for its operation and form the plant in a compact size by incorporating a heat exchanger for carrying out at least one part of fuel treatment inside a heat exchanger which heats water so as to generate steam. CONSTITUTION:Water is heated by a waste heat source having a high temperature so as to generate steam, while fuel treatment including evaporation of methanol fuel and heat decomposition reaction or steam reforming reaction is carried out by the waste heat source. A heat exchanger for carrying out at least one part of fuel treatment is incorporated inside a heat exchanger which heats water so as to generated steam. It is thus possible to improve efficiency in a gas turbine/steam turbine combined power generating plant which used reformed fuel for its operation to form the plant in a compact size.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for recovering heat from the exhaust gas of a prime mover such as a gas turbine engine, a diesel engine, or a gas engine, and an apparatus for recovering waste heat from a chemical process.

0002

2. Description of the Related Art FIG. 20 is a system diagram showing an example of a conventional combined power generation facility that recovers waste heat from gas turbine exhaust to drive a steam turbine.

In this example, first, intake air from the atmosphere is compressed by a compressor (C), and the compressed air is passed through a gas turbine combustor (
CC), the temperature is raised by the fuel (f), and the gas turbine (GT) is operated at a predetermined turbine inlet temperature. After the power generated by the gas turbine (GT) covers the load of the compressor (C), the remaining power is converted into electric power by the generator (GEN1) to generate electricity. Gas turbine (GT) exhaust (a) is 500
Due to the high temperature of ~600℃, a waste heat recovery boiler (HRSG) is used.
The heat is recovered and discharged into the atmosphere from the chimney (STCK) at 100-200°C. In the waste heat recovery boiler (HRSG), (LP-ECO) is a low pressure energy saver, (LP-EVA
) is a low-pressure evaporator, (HP-ECO) is a high-pressure economizer, (H
P-EVA) indicates a high-pressure evaporator, and (SH) indicates a superheater. That is, the waste heat recovery boiler (HRSG) of this example is a double pressure system of high pressure steam (HP-S) and low pressure steam (LP-S). This steam expands in a steam turbine (ST), rotates it, and then rotates a generator (GEN2) to generate electricity. The turbine exhaust (steam) is passed through the condenser (COND).
), it is cooled by circulating water such as seawater and becomes condensate. This condensate is transferred by a feed water pump (P) for recirculation and use as boiler feed water for a waste heat recovery boiler (HRSG).

[0004] Combined power generation includes a gas turbine/steam turbine separate type as shown in the above example, as well as a gas turbine/steam turbine coaxial type. Figure 21 shows the gas turbine
FIG. 1 is a system diagram showing a conventional example of a coaxial steam turbine type, and in this example, a methanol fuel processing device is also combined.

In this example, heat transfer tubes for both the steam system that drives the steam turbine (ST) and the water-steam system that supplies heat to the methanol fuel processing device are connected to the same waste heat recovery boiler (H
Heat is recovered by mixing it in the RSG). That is, the preheater (PRE-H) of the methanol fuel processing equipment
Hot water from the primary heater (1-HTR) in the waste heat recovery boiler (HRSG), the secondary Hot water from heater (2-HTR) and high pressure economizer (VHP-ECO) to high pressure evaporator (VHP-E
VA) and superheated steam via a high-pressure superheater (VHP-SH) (condensed water is fed back to the ultra-high pressure evaporator (VHP-EVA)). Liquid methanol (Me
OH) is processed by such a methanol fuel processing device to become gaseous fuel (Gf). On the other hand, in the steam system for driving a steam turbine, low-pressure steam passes through a low-pressure economizer (LP-ECO) or a low-pressure evaporator (LP-EVA), and a high-pressure economizer (HP-ECO) and a high-pressure evaporator ( HP-E
VA), high pressure superheater (primary and secondary) (1-HPSH
), (2-HPSH) and high-pressure superheated steam,
Each is supplied to a steam turbine (ST), and the steam turbine exhaust (steam) is returned to water in a condenser (COND), pressurized by a feed water pump (P), and circulated as boiler feed water.

[0006] In Fig. 21, (C) is a compressor, (CC
) is a gas turbine combustor, (GT) is a gas turbine, (
GEN) indicates a generator, and (STCK) indicates a chimney.

FIG. 22 is a system diagram showing another example of a methanol fuel processing apparatus. In this example, the preheater (PRE-H
TR), evaporator (EVA), heater (HTR), reactor (REA), and superheater (MeSH).
, d2, d3, d4, d5. The liquid methanol then absorbs the necessary amount of heat from the heating medium while passing through these heat transfer parts one after another, and the gas fuel (
Gf).

[0008] The above reactor (REA) and superheater (MeSH
) has a built-in catalyst (CATA). This catalyst (
The type and amount of CATA is determined depending on the reaction specifications, such as for either thermal decomposition reaction (Cracking) or steam reforming reaction (Steam Reforming), or for mixed use of both. In the presence of each catalyst, the following reactions (1) and (2) proceed, exhibiting the characteristics that ``a large amount of heat is absorbed by thermal decomposition, and a large amount of hydrogen is produced by steam reforming.''

[0009]

[Chemical formula 1]

[0010] Here, the endothermic amounts QC and QR differ somewhat depending on researchers, literature, etc., but it can be said that steam reforming has an endothermic amount that is about 70% of that of thermal decomposition. (For example, QC
is 30.6kcal/mol, QR is 20.
(8 kcal/mol) In the case of thermal decomposition, water (steam) is not used in the main reaction, but a very small amount of water may be added to prevent carbon deposition on the catalyst. (For example, H2O/CH3OH = 0.1 molar ratio) Although the catalysts are fundamentally different between thermal decomposition and steam reforming, the difference can be understood as whether the amount of water in the treated fluid is a trace amount or an equimolar amount.

Now, in FIG. 22, first, liquid methanol is heated in a preheater (PRE-HTR) to near the evaporation temperature and slightly lower than the evaporation temperature (lower approach point temperature difference). The gaseous methanol produced in the evaporator (EVA) is heated to a reaction temperature (e.g. 200°C) in the heater (HTR).
After the temperature is raised to 1, the reactor is introduced into the reactor (REA). The above-mentioned endothermic reaction of type ① or type ③ proceeds by the catalyst (CATA) built in the reactor (REA), and (CO
+2H2 + other) or (CO2 +3H2 +
(Others) converted into gas fuel (Gf) (Others)
is unreacted CH3OH and side reaction products. ). When increasing the heat capacity of gas fuel (Gf), use a superheater (MeS).
H) to raise the temperature and add sensible heat. In addition, the superheater (MeS
By preliminarily filling the inside of H) with catalyst (CATA), the catalyst (CATA) in the reactor (REA) can be
When the capacity of d5 decreases, it becomes possible to continue the reaction under a higher temperature heating medium d5.

The addition of water to the methanol system is determined by the sign (Rw
) It is possible to deal with either liquid phase mixture shown by (Rs) or gas phase mixture shown by (Rs), but (heater/evaporator/preheater)
heat exchanger design (heat transfer balance, material, capacity, operability,
(two-component evaporation, etc.), gas phase mixing (Rs) is preferable. The heating medium d1, d2, d3, d4, d5 is
As the process progresses, a higher temperature is adopted (d5
>d4 >d3 >d2 >d1).

The processing temperature of the methanol fuel system shown in the above figure, and the temperatures of each part of the gas turbine exhaust system and water/steam system are shown in the lower left part of FIG. In a methanol fuel system, the temperature changes from Mi→Me→M while passing through five types of heat exchange parts.
Changes from r→Mg. The temperature in the latent heat of vaporization recovery area of the evaporator (EVA) and the reaction heat recovery area of the reactor (REA) is considered to have a flat characteristic (constant for Me and Mr), but the temperature in the latter depends on the characteristics of the catalyst. Temperature characteristics can be freely set.

This figure also shows the temperature of each part of the gas turbine exhaust system and water/steam system, which are heat sources. The gas turbine exhaust system consists of five heat transfer parts of the waste heat recovery boiler.
The temperature changes as Ei → E1 → E2 → E3 → E4 → Ee. The water/steam system is under double pressure, and the temperature change is Si→Sl→Se→Sh. Low pressure steam has a temperature Sl,
After high-pressure steam is generated at a temperature Se, it is superheated to a temperature Sh and used in processes such as driving a steam turbine. In this example, approximately half of the heat recovered from the gas turbine exhaust (approximately 40% in one example of pyrolysis) is utilized for fuel processing, and the remainder is extracted as steam (for processes such as turbine drive). The heated Mi or Mg is replaced by the heating source Si.
, Sh or Ei to Ee, many systems exist.

[0015]

[Problems to be Solved by the Invention] Conventionally, the steam generation part, that is, the waste heat recovery boiler (HRSG), contains a turbine drive steam system and a fuel processing heat medium (water-steam) system, so that There was a drawback. 1) The heat transfer area of the steam generation section is determined and manufactured based on the rated conditions, so if the fuel processing amount decreases at partial load of the gas turbine, the amount of heat recovered by the fuel processing heat medium system will decrease, resulting in a reduction in the turbine drive steam system. Although the temperature of the inlet exhaust gas of the high-pressure evaporator becomes relatively high and the amount of steam increases slightly to match the heat transfer area, the distribution ratio of the recovered heat amount between the steam system and the heat medium system collapses, whereas the heat transfer Since the area remains constant at the design point, the efficiency of heat recovery from exhaust air deteriorates. 2) The heat medium (water-steam) circulating between the waste heat recovery boiler (HRSG) and the methanol fuel treatment system (MeOH) is
This involves heat dissipation from the piping, which reduces the rate at which recovered heat is utilized for fuel processing. 3) Heat exchanger tube arrangement in the waste heat recovery boiler (Tube B
Ank) are large and complicated, and furthermore, the heat medium piping to the methanol fuel processing device is complicated with the turbine drive steam system, making the manufacturing complicated. Compared to the case of combined power generation using liquid methanol as it is without fuel processing, the space of the waste heat recovery boiler is expanded by the heat medium system, and additional space is required to install the methanol fuel processing equipment, making the plant layout difficult. The above disadvantages are great. 4) Control of the flow rate and temperature of the turbine driving steam system and the fuel processing heat medium system is basically performed separately, but mutual control is required in the distribution of the heat transfer amount of the gas turbine exhaust, which is complicated. 5) In order to circulate the heat medium between the waste heat recovery boiler and the methanol fuel processing device, additional power is required, increasing the power of the plant's auxiliary equipment.

[0016]

[Means for Solving the Problems] In order to solve the above-mentioned conventional problems, the present invention heats water using a high-temperature waste heat source to generate steam, and also evaporates and thermally decomposes methanol fuel using the same waste heat source. In an apparatus that performs fuel processing including a reaction or a steam reforming reaction, a heat exchanger that performs at least a part of the fuel processing is incorporated into a heat exchanger that heats the water to generate steam. This paper proposes a waste heat recovery device with characteristics.

[0017]

[Operation] 1) Since piping for fuel processing heat medium is not used, there is no heat loss from the piping, and the utilization rate of recovered heat is increased. Furthermore, there is no need to route heat medium piping, and the entire device becomes smaller. 2) Since the fuel processing heat transfer tubes are incorporated into each part of the waste heat recovery boiler, they can be arranged more compactly around the waste heat recovery boiler in the gas turbine exhaust duct, compared to the conventional individual arrangement. 3) By inserting long fuel processing system heat transfer tubes from the drum (or header) on the waste heat recovery boiler side to the inside of the heat transfer tubes of the waste heat recovery boiler, the heat transfer area is secured and the number of tubes is increased. This allows the fuel processing system to be arranged more compactly. 4) The total amount of heat of the turbine driving steam and fuel processing heat medium is
Since the waste heat recovery boiler recovers the heat almost constantly, even if the heat used in the fuel processing system increases or decreases, a constant pinch point temperature difference (heat recovery characteristics in the evaporator) is maintained at all times. Changes in the heat balance with the gas turbine exhaust are extremely small. 5) The heat transfer tubes of the fuel processing equipment are housed in the waste heat recovery boiler and are surrounded by a high-pressure water-steam system, so even if the heat transfer tubes are damaged, moisture in the fuel will increase. However, the risk of contamination of the steam system with fuel is small, and there is no risk of fuel leaking into the gas turbine exhaust system.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 to 5 each show an embodiment in which a heat exchanger for processing fuel is integrated into a heat exchanger for generating steam in accordance with the present invention. (Fuel processing will be explained below based on the case where there are the most configurations as shown in Fig. 22, but for example, evaporation alone may be performed using two configurations: a preheater (PRE-HTR) and an evaporator (EVA), or a catalyst (CATA).
Some of them may also be implemented, such as the three configurations that also include a superheater (MeSH) that does not have a built-in superheater (MeSH). ) First, FIG. 1 shows an embodiment implemented as a single-stage evaporator system, and the pressure of high-pressure steam is realized by a high-pressure feed water pump (P) and its pressure adjustment. High pressure evaporator (HP-EVA) drum (DR)
A methanol-fueled reactor (REA) is installed inside the heat exchanger tube.
), heater (HTR), evaporator (EVA), preheater (P
RE-HTR) is arranged, and the fuel is superheated in a primary heater (HTR (1)) using superheated steam exiting the superheater (SH) as a heat medium. The superheated steam is transferred to the primary heater (HTR (1)
) are bypassed and supplied to the steam turbine (ST) together with low pressure steam. In Figure 1, HB is a primary heater (H
TR (1)) bypass line, SHB is superheater (SH)
Bypass line is shown. Further, the symbol * indicates that a catalyst (CATA) is built in as required (the same applies to FIGS. 2 to 5).

FIG. 2 now shows an embodiment implemented as a two-stage evaporator system. This example uses a high pressure evaporator (
A methanol-fueled reactor (REA) and a heater (HTR) are installed inside the drum and heat exchanger tube of the HP-EVA, and a methanol-fueled reactor (REA) and heater (HTR) are installed inside the drum and heat exchanger tube of the low-temperature evaporator (LP-EVA). evaporator (EVA), preheater (PRE)
-HTR), and the rest is the same as the embodiment shown in FIG.

FIG. 3 now shows an embodiment implemented as a two-stage evaporator/reheat system. In this example, the superheater (SH) of the waste heat recovery boiler in the example of FIG. , and then reheated in the second superheater (SH2) and then supplied to the steam turbine (ST) together with low pressure steam.

FIG. 4 shows an embodiment implemented as a two-stage evaporator/regeneration/heating system. In this embodiment, unlike the embodiment shown in FIG. HTR (2)) is also available. In this case, the second high-pressure economizer (HP-ECO2) is used to raise the temperature of the water supply whose temperature has been reduced by the second heater (HTR (2)) again. Figure 6 shows the balance of heat recovery and heat utilization in the gas turbine exhaust system, water-steam system, and methanol fuel system in this case. The low pressure steam is supplied to the steam turbine (ST) at a flow rate corresponding to Q1 and the high pressure steam at a flow rate corresponding to Q21+Q22+Q23.

The embodiment shown in FIG. 5 is a three stage evaporator regeneration/heating system. In this example, in order to set the pressure of the steam system in three stages, a high-pressure evaporator (
VHP-EVA), a high-pressure economizer (VHP-ECO) and a water pump (P2) corresponding to the third pressure. In this case, a high pressure evaporator (VHP-E
A methanol-fueled reactor (REA) and a heater (HTR) are placed inside the drum and heat transfer tube of the VA), and the higher-temperature saturated water and saturated steam obtained by raising the pressure to high
It is used as a heat medium. This high-pressure steam is superheated in a second superheater (SH2) and is supplied to a steam turbine (ST) together with high-pressure steam and low-pressure steam.

In the above embodiment, the configuration of the first and second heaters (HTR(1)) and (HTR(2)) is installed in the heat exchanger tube of the waste heat recovery boiler (HRSG) as described later. If the heat transfer tubes of the fuel processing device are housed, the need for reheating will be reduced and the device can be made smaller and simpler.

In each of the embodiments shown in FIGS. 1 to 5 above, the catalyst (CATA) in the reactor (REA) is often subjected to hydrogen reduction operation at the time of equipment assembly or refilling. requires a low-temperature heat medium of 150 to 250°C. Therefore, the load on the gas turbine is reduced to lower the exhaust temperature at the inlet of the heat recovery boiler (HRSG), and the discharge pressure of the water pump (P), that is, the drum internal pressure, is also reduced as necessary to achieve a temperature of 150 to 250°C. Operate to produce saturated steam. In the embodiment of FIG. 5, both of the two water supply pumps (P1) and (P2) are controlled to low pressure.

[0025] Also, as mentioned above, the first heater (HTR
The superheater (MeSH) of the methanol fuel system in (1)) is equipped with a catalyst (CATA) as needed, and the reactor (R
EA) Prepare for deterioration of the performance of the internal catalyst. In the hydrogen reduction, a bypass line (SHB) of the superheater (SH) of the exhaust heat recovery boiler is used to bypass the high pressure evaporator (H
The process is carried out using 150-250°C steam from P-EVA) as a heating medium.

Table 1 summarizes the situation of equipment integration in the embodiments shown in FIGS. 1 to 5.

[0027]

[Table 1]

FIG. 7 and FIG. 8 are both longitudinal sectional views showing the basic structure of the heat exchanger tube of the fuel processor. Figure 7
The one shown in Fig. 1 is a double tube by inserting an internal tube (IT) inside a methanol heat transfer tube (RT).
It is an integrated system that handles fuel input and output at the same location. In this method, only one end is attached to the drum (DR) or header (HD) of the waste heat recovery boiler (HRSG), so there is no restriction on thermal expansion of the heat transfer tubes (RT) and the inner tubes (IT). Therefore, the advantages are: ■It can be inserted into the exhaust heat recovery boiler heat transfer tube, ■It can be installed and removed from one direction, and ■The heat transfer tube (RT) can be installed in any direction such as downward, upward, or sideways. There is.

[0029] Many end shapes can be considered,
Although not particularly limited, the example shown in FIG. 7 is the simplest one. In other words, a passage for the treated fuel (Gf) is provided around the mounting flange of the internal tube (IT), and the exhaust heat is recovered together with the mounting flange of the heat transfer tube (RT) using bolts (B). Attach to the drum (DR) or header (HD) of the boiler (HRSG). In this case, first, the heat transfer tube (RT) and the inner tube (IT) are assembled together (the flanges are fastened together), and the connection to the heat recovery boiler (HRSG) is performed using another bolt.

The raw fuel (f) is supplied to one end of the heat transfer tube (RT) by the inner tube (IT), and the flow direction is changed at the other end to flow between the heat transfer tube (RT) and the inner tube (IT). While flowing through the annular cross-sectional area, heat is recovered from the surrounding heating medium (d) and taken out from the end face as treated fuel (Gf). Raw fuel (f)
By preheating with the treated fuel (Gf) while flowing through the internal tube (IT), it is possible to effectively utilize heat transfer through the internal tube (IT) and promote miniaturization.

On the other hand, the assembly method shown in FIG. 8 uses two end faces of a heat recovery steam generator (HRSG) to hold a methanol heat transfer tube (RT), and handles fuel input and discharge at opposing positions. It is. In the example shown in Figure 8(a), the flange of the heat transfer tube (RT) is connected to the heat recovery boiler (HRS).
G) is fixed to one end of the drum (DR) or header (HD) with a bolt (B), and a seal tube (S) is attached to the opposite end.
Fix the flange of F) with bolts (B) and attach the heat exchanger tube (R
T) and the seal tube (SF) are allowed to slide relative to each other to cope with thermal elongation. Heat transfer tube (RT) and exhaust heat recovery boiler (H
RSG), between the heat transfer tube (RT) and the seal tube (SF), sealing materials (SL1) and (SL2) are filled, or other appropriate mechanisms are used to prevent fluid leakage. The raw fuel (f) flows in one direction inside the heat transfer tube (RT) and becomes a processed fuel (Gf). This assembly method is similar to the so-called shell-and-tube method of heat exchangers, so if the above-mentioned measures against thermal expansion are solved, the shell-and-tube method can be used.

[0032] Instead of relative sliding between the heat transfer tube (RT) and the seal tube (SF), an expansion joint can also be applied. This is effective when prioritizing the sealing of the seal tube (SF) and heat transfer tube (RT) results in insufficient slippage between them. Although the one shown in FIG. 8(b) is one example, any type of expansion/contraction system can be used as the expansion joint (BE). As a result of inserting the expansion joint (BE), the heat transfer tube (RT) has a dual configuration of a flange side (symbol RT1) and a seal tube side (symbol RT2).

FIGS. 9 and 10 are schematic diagrams showing the state in which heat is transferred from the gas turbine exhaust to the methanol fuel. FIG. In this case, FIG. 10 shows the case of a heating heat exchanger tube such as a superheater or an economizer.

In the configuration example shown in FIG. 9(b), an evaporation tube (ET) is installed in the exhaust gas as an evaporation heat transfer tube of a normal waste heat recovery boiler, and a drum (DR) for gas-liquid separation is installed above the evaporation tube (ET). (C
The saturated water (b) is recirculated (T) to the evaporator tube (ET) (
(natural circulation or forced circulation using a circulation pump, etc.). In this configuration, a methanol-fueled heat transfer tube (RT) is built inside the evaporation tube (ET), and saturated water (b) evaporates on the wall of the evaporation tube (ET), forming a gas-liquid two-phase flow, resulting in a violent flow. Mixing turbulent heat transfer facilitates heat transfer from the evaporator tube (ET) to the heat transfer tube (RT). In this case, the increase or decrease in the heat transfer area of the heat transfer tube (RT) can be handled within the evaporation tube (ET). In other words, a heat recovery steam generator (HRSG)
Since the amount of heat recovered from the gas turbine exhaust gas is uniquely determined, the heat transfer area of the exhaust gas recovery boiler (HRSG) can be freely designed for the heat transfer tube (RT) while keeping the heat transfer area at a predetermined value. In addition, the heat transfer balance from the heat medium, saturated steam and saturated water, to the heat transfer tube (RT) is always maintained in a responsive manner.

FIG. 9(a) shows the state of heat transfer. The heat medium (b) flowing between the evaporator tube (ET) and the methanol-fueled heat transfer tube (RT) is a turbulent mixed fluid of saturated water (I) and saturated steam (II). Water near the heat transfer tube (RT) (III
) and steam (IV) transfer heat (h1) to the heat transfer tube (RT).
), but the temperature recovers due to strong turbulent mixing of gas-liquid two-phase flow. That is, the water (III) whose temperature has been reduced diffuses to the position of code (III1) and becomes saturated steam (III2).
), and the steam (IV) is cooled down to become saturated water and replaced by saturated steam (IV1). The amount of heat in the heat medium that has decreased due to heat transfer (h1) is immediately compensated for by the increase in heat input (h2) from the gas turbine exhaust (a). In this way, in the heat transfer through the evaporative heat transfer tube shown in FIG. 9(a), the temperature of the heat medium (b) is constant, and the heat transferred to the methanol fuel-based heat transfer tube (RT) is , is immediately replenished by the latent heat of the heating medium (saturated steam). In addition, the evaporation tube (ET
), saturated steam is intensively replenished by heat recovery from the gas turbine exhaust. A similar heat transfer situation exists within the steam drum (DR).

Next, in the case of heating heat exchanger tubes such as superheaters and high-pressure economizers, as shown in FIGS. (HD), and the heat transferred from the heating medium (superheated steam (SS), high temperature feed water (W)) to the methanol fuel system heat transfer tube (RT) is covered by its sensible heat. SS) temperature decreases. That is, as shown in FIG. 10(a), water (III) or steam (
IV) is cooled by heat transfer (h1). However, since the temperature difference between the gas turbine exhaust (a) and the water (III) increases, (h2) increases, and heat replenishment is immediately performed. In addition, as shown in Fig. 10(b), heat transfer (h1),
(h2) is performed at the same time, Fig. 10(c
), heat transfer (h
The heat medium (W or SS) whose temperature has decreased due to heat absorption in 1) needs to be reheated in a heat recovery boiler (HRSG). (See FIGS. 3 to 5 above) When the heat transfer tubes of the fuel processing device are housed in the exhaust heat recovery boiler in this way, the arrangement within the heating heat transfer tubes has the great advantage of being compact and simple.

FIG. 11 shows the integrated heat exchanger assembled in a vertical position, with FIG. 11(a) being a side view and FIG. 11(b) being a side view.
is a front view. This is a vertically arranged integrated type heat transfer tube that can be inserted into the waste heat recovery boiler heat transfer tube, and can be removed from the steam drum (DR) or header (HD).
) is pulled upward. Mixed use of methanol fuel-based short heat transfer tubes (RT1) and long heat transfer tubes (RT2) enables efficient distribution within the steam drum, header, and heat transfer tubes of a waste heat recovery boiler. By using long heat transfer tube RT2, ■
Reduced total number of RTs, ■ Simplified maintenance due to ■ ■ Simplified piping system due to ■ ■ Easier process management by incorporating many fuel treatment processes (Figure 22) into one gas turbine, ■ Gas turbine It has advantages such as good heat transfer from exhaust gas to treated fuel.

In the configuration of the exhaust heat recovery boiler (for example, FIG. 5), the heating medium is saturated steam, saturated water, and high-temperature water in each configuration of the evaporator, second heater, economizer, and first heater/superheater, respectively. , different from superheated steam. The evaporator is composed of an evaporative heat transfer tube (ET), a gas-liquid separation drum (DR), and a downcomer tube (CT) (Fig. 9(b)), and the second heater and economizer are composed of a heating tube (
Combination of WT) and header (HD) (Fig. 10(b),(c)
)), the first heater/superheater is a heating tube (SH) and a header (H
D) is the combination. In assembling the first heater/superheater, the superheater bypass control and its piping shown in FIGS. 1 to 5 can be omitted.

FIG. 12 also shows the integrated heat exchanger assembled in a horizontal position, with FIG. 12(a) being a side view and FIG. 12(b) being a side view.
is a front view. This is the steam drum of the exhaust heat recovery boiler (
DR) or a header (HD) in which integrated heat exchanger tubes are arranged laterally. The long heat transfer tubes (RT3) and the short heat transfer tubes (RT1) are efficiently distributed with respect to the length between the end plates D1. Attachment to the mirror plate is done at one end. The raw fuel (f) supplied from the fuel manifold (D3) is sent to the inner space of the fuel manifold (D3) after being processed, so it is discharged to the system from the nozzle of the lid (D2) as processed fuel (Gf). . The advantage of this example is that fuel can be charged and discharged at both ends corresponding to the head plate.

FIG. 13 is a diagram showing how the integrated heat exchanger is assembled in a multilayer arrangement. In this example, in order to increase the heat transfer area on the fuel processing side, a plurality of steam drums or headers are arranged in layers to secure a place for installing heat transfer tubes and to communicate the heat medium. That is, the horizontal arrangement in Fig. 12 is made into two stages, and the heating medium of the evaporator is saturated water and saturated steam in the drum (D1).
There is saturated steam in the drum (D2).

FIG. 14 is a diagram showing the assembly state of the assembly type heat exchanger tube. In this method, the attachment to the end plate (D1) is done at both ends, so all heat exchanger tube types are long heat exchanger tubes (
RT4). Raw fuel (f) is input from one end, and processed fuel (Gf) is discharged from the other end. Separate fuel distribution to each heat exchanger tube is not necessary, and the structure can be made simpler than that in FIG. 12 to that extent.

FIG. 15 shows an example in which the heat exchanger tubes of the assembly method shown in FIG. 14 are arranged in layers as shown in FIG. 13.

FIG. 16 illustrates a specific example of the structure of the integral type fuel processing device heat exchanger tube whose basic structure is shown in FIG. 7. First, in the example shown in FIG. 16(a), the raw fuel (f) is supplied through the internal tube (IT), and the heat transfer tube (RT)
It is processed using heat input from the fuel and discharged as processed fuel (Gf). The raw fuel (f) flowing inside the internal tube (IT) is partially heated by the heat possessed by the processed fuel (Gf), and has a larger effective heat transfer area than simple unidirectional flow (see Figure 17(a) below). It can be taken in large quantities. Furthermore, since the heat transfer boundary layer becomes thinner due to the diverted flow (g'), a high amount of heat transfer can be ensured in the region indicated by the symbol (RT').

Next, in the example shown in FIG. 16(b), many injection holes (i) are provided in the inner tube (IT), and the heat transfer tube (RT
) Uniform distribution of the jet flow (j) on the inner surface. Jet flow (
j) is evaporated on the surface of the heat transfer tube (RT), and the rest is a thin liquid film (
k) and evaporates on the entire inner surface of the heat transfer tube (RT).

The example shown in FIG. 16(c) is the same as that shown in FIG.
In the form of combining each heat exchanger tube shown in (a) and (b),
Preheating of the raw fuel (f) using the processed fuel (Gf) is also being actively incorporated.

In the example shown in FIG. 16(d), the input fuel (f) is inside the inner tube (IT) and the heater (HT) of the heat transfer tube (RT).
After being heated to the reaction temperature in the R) section, the reactor (REA) is heated to the reaction temperature.
) in the region of the catalyst (CATA) filled in the heat exchanger tube (R
T) It undergoes reactions such as thermal decomposition and steam reforming while absorbing heat from the external gas turbine exhaust gas to become treated fuel (Gf).

[0047] The long heat exchanger tube (R
As T2 ) and (RT3 ), the heat exchanger tubes shown in FIGS. 16(a) to 16(d) may be simply made longer, but the example shown in FIG. 16(e) below may be used. The entire process from preheater to superheater is built into the heat transfer tube. Since the heat transfer tube including the reactor (REA) selects a heat medium temperature that matches the reaction conditions, a higher temperature heat medium is required to heat the sensible heat in the superheater (SH). However, if a heat medium with some thermal margin is used, part of the heating amount can be covered by the superheater (SH) region.

Of the integrated type heat transfer tubes shown in FIGS. 16(a) to 16(e), FIGS. 16(a) and 16(b) are single-function heat transfer tubes, and FIGS. 16(c) to 16(e) are multi-function heat transfer tubes. Although it is a heat exchanger tube,
These uses are approximately as follows. In other words, the superheater is shown in Figures 16(a) and (e), the reactor is shown in Figures (d) and (e), and the heater is shown in Figure 16.
6(a),(c),(d),(e),Fig. 16 for the evaporator.
(b), (c), (e), and the preheater is shown in Figs.
Those shown in c) and (e) can be used, respectively. Then, a suitable structure is selected in consideration of heat transfer conditions and storage space.

Next, FIG. 17 shows an example of the specific structure of the assembly type fuel processing device heat transfer tube whose basic structure is shown in FIG. 8(a). First, in the example shown in FIG. 17(a), raw fuel (f) is supplied from the seal tube (SF) side, processed by heat input from the heat transfer tube (RT), and processed fuel (G
f).

Next, in the example shown in FIG. 17(b), an inner tube (IT) is provided inside the seal tube (SF). The inner tube (IT) is provided with many injection holes (i) to uniformly distribute the injection flow (j) of the fuel onto the inner surface of the heat transfer tube (RT). The jet stream (j) evaporates on the surface of the heat transfer tube (RT), and the rest becomes a thin liquid film (k) and evaporates over the entire inner surface of the heat transfer tube (RT).

In the example shown in FIG. 17(c), the heat input from the gas turbine exhaust causes thermal decomposition and steam reforming of the raw fuel (f) in the catalyst (CATA) packed in the heat transfer tube (RT). After evaporation and heat treatment, the fuel (
Pay out Gf).

In the example shown in FIG. 17(d), the evaporated fuel (f) is supplied, and the heating (HTR section) and reaction (RE
Part A) Process and discharge as processed fuel (Gf).

[0053] The long heat transfer tube (RT4) in FIG.
Although it is also possible to use a simple elongated heat exchanger tube shown in FIGS. 17(a) to 17(d), the example shown in FIG. 17(e) (EVA
), heating (HTR), reaction (REA), and superheating (SH). Reactor (
For the heat transfer tubes including REA), select a heat medium temperature that matches the reaction conditions. To heat sensible heat with a superheater (SH),
Furthermore, a high-temperature heating medium is used. However, if a heat medium with some thermal margin is used, part of the heating amount can be covered by the superheater (SH) region.

The assembled heat exchanger tubes shown in FIGS. 17(a) to 17(c) are single-function heat exchanger tubes, FIGS. 17(d) and 17
(e) is a multifunctional heat exchanger tube. These uses are approximately as follows. In other words, the superheater is equipped with Figures 17(a) and (
Figures 17(c), (d), and (e) are shown in Fig. 17(c), (d), and (e) for the heat exchanger tube and reactor.
17(a), (d), (e) for heat exchanger tubes and heaters.
17(b) and (e) in the evaporator,
The heat exchanger tube shown in FIG. 17(a) can be used for each preheater. Then, a suitable structure is selected in consideration of heat transfer conditions and storage space.

FIGS. 18 and 19 are perspective views showing an example of the assembled appearance of the integrated heat exchanger. Heat exchanger tube (E) of the exhaust heat recovery boiler placed in the gas turbine exhaust duct (ED)
T) and (HT) are integrated into a drum (DR) or header (HD) for each group.

[0056] When the drum or header is a cylindrical shell,
Horizontal arrangement where its center line is perpendicular to the gas turbine exhaust a (
18(a)) or parallel vertical arrangement (FIG. 18(b)). The heat exchanger tubes can be removed in the five directions shown.

In FIG. 18(c), a box-shaped drum (header) is used to facilitate the arrangement and attachment of the heat transfer tubes of the fuel processor, and the heat transfer tubes are divided into groups by partition walls. This partition wall has a heat insulating structure to prevent heat transfer from one side to the other. The exterior will have a shell structure that can withstand internal pressure by using reinforcing materials such as ribs.

FIG. 19 shows the economizer header of the exhaust heat recovery boiler,
FIG. 3 is a perspective view showing an example in which the evaporator drum and superheater header are box-shaped. FIG. 4 is used as an example of the element arrangement of the exhaust heat recovery boiler. Since the direction of the partition wall W (perpendicular or parallel to the exhaust gas a) can be freely selected, it can be used in addition to the diagonal line W in the figure, for example, between the economizer (ECO) and the evaporator (EVA), or between the evaporator (E
It is also possible to provide a partition wall between the VA) and the superheater (SH) to form a single structure that integrates these three elements. In the illustrated example, the drum (header) has a three-part structure that is integrated with the exhaust heat recovery boiler heat exchanger tube.

By this method, (S
H1), (SH2), (HP-ECO1), (HP-E
CO2) can be easily divided into groups, and gaps between the group heat transfer tubes (for example, reference numeral CL in FIG. 18(a)) can be eliminated, allowing for a compact design. In Figure 19, the fluid flow of the exhaust heat recovery boiler is changed by supplying high temperature water (w1) from the low temperature evaporator (LP-EVA) to the lower header (L-HD1) and supplying superheated steam (SS) to the superheater (SH2). ) until it is taken out. The high temperature water (w1) is passed through the first economizer (EC
O1) After moving up the heat transfer tube and transferring heat to, for example, the integrated type heat transfer tube RT2 in FIG. 11, it is taken out as high temperature water (w2). This high temperature water (w2) is supplied to the lower header (L-HD2), rises through the second economizer (ECO2) heat exchanger tube, and is heated up. The economizer outlet water (W3) mixes with the saturated water in the evaporator (EVA) drum, reaches the lower header through the downcomer tube (CT), and then ascends through the evaporator (EVA) heat transfer tube to produce steam. Occur. For example, when RT2 is interpolated, transmission to RT2 is performed under a gas-liquid two-phase flow of saturated water and saturated steam. The saturated steam (S1) from the drum is transferred to the first superheater (SH
1) to the lower header (L-HD1) and the first superheater (
SH1) For example, heat transfer tube (RT2) while ascending the heat transfer tube.
) and then taken out as (S2). (
S2) reaches the lower header, then the second superheater (SH2
) The heat transfer tube is raised to raise the temperature and taken out as superheated steam (SS).

[0060]

[Effects of the Invention] 1) Since the heat transfer tubes of the fuel processing device are incorporated inside the drum, header, heat transfer tubes, etc. of the waste heat recovery boiler, (1) the device arrangement is compact; ■The evaporator can extract the residual heat used in fuel processing as main steam, eliminating the need for conventional heat medium piping and its control. 2) Since the waste heat recovery boiler, fuel processing system, and heating medium are in the same system, compared to the conventional system in which the boiler and fuel processing system are separate systems and the heating medium circulates between them, the power for transporting the heating medium outside the system is reduced. This is not necessary, and the on-site power consumption can be reduced accordingly. ■Since there is no heat loss from circulation piping, the utilization rate of boiler recovery heat is high. 3) In the boiler evaporator, the heating medium is a two-phase flow of saturated water and saturated steam, and the heating medium temperature remains constant even if the reaction heat is consumed for fuel processing. Since it can be maintained as designed and has a wide constant temperature range, it is easy to manage the performance and life of the catalyst. ■Even if the fuel processing load (reaction heat absorption amount) increases or decreases, the amount of steam becomes a balancing factor and the heat load on the boiler heat exchanger tubes remains constant, making it possible to maintain a high amount of heat recovery from the gas turbine exhaust and improve the exhaust temperature distribution. It is less likely to be disturbed. 4) To reduce the capacity due to catalyst performance life (degradation over time, etc.), increase the internal pressure of the evaporator drum to raise the heating medium temperature, or activate the catalyst (high temperature atmosphere) packed in the superheater. This makes it easy to respond. 5) The fuel processing heat transfer tube in the boiler evaporator is used under highly turbulent heat transfer in a two-layer flow (saturated water and saturated steam), which saves (optimizes) the heat transfer area and makes it more compact. It's advantageous. 6) Surround the heat transfer tubes of the fuel treatment system with higher pressure water.
By using a steam-based heating medium, it is possible to prevent contamination of the heating medium at the time of a blowout and furthermore prevent leakage of combustible fluid into the gas turbine exhaust gas. 7) When arranging fuel processing heat transfer tubes in the drum or header of a boiler, a conventional cylindrical pressure-resistant vessel is used, but when the fuel processing heat transfer tubes are also inserted into a group of boiler heat transfer tubes, A flat part is provided on the top of the drum or header for convenience in mounting and layout design. Compared to the flat portion of a cylindrical container, by making the top and side surfaces of a box-shaped container flat, layout design (piping pitch, etc.) becomes easier.

[Brief explanation of the drawing]

FIG. 1 shows a first embodiment of the invention in which a heat exchanger for processing fuel is integrated into a heat exchanger for generating steam as a single-stage evaporator system; It is.

FIG. 2 shows a second embodiment of the invention in which a heat exchanger for processing fuel is integrated into a heat exchanger for generating steam as a two-stage evaporator system; It is.

FIG. 3 shows a third embodiment of the present invention in which a heat exchanger for processing fuel is integrated into a heat exchanger for generating steam as a two-stage evaporator/regeneration system. FIG.

FIG. 4 shows a fourth embodiment of the invention in which the heat exchanger for fuel processing is integrated as a two-stage evaporator/regeneration/heating system inside the heat exchanger for generating steam; It is a figure which shows an example.

FIG. 5 shows a fifth embodiment of the present invention in which a heat exchanger for processing fuel is integrated into a heat exchanger for generating steam as a three-stage evaporator/regeneration/heating system; It is a figure which shows an example.

FIG. 6 is a diagram illustrating the balance between heat recovery and heat utilization in the embodiment shown in FIG. 4 above.

FIG. 7 is a diagram showing the basic configuration of an integrated type heat transfer tube of a fuel processing device according to the present invention.

FIG. 8 is a diagram showing the basic configuration of an assembled heat exchanger tube of a fuel processing device according to the present invention.

FIG. 9 is a schematic diagram showing a situation in which heat is transferred from gas turbine exhaust to methanol fuel in the evaporative heat transfer tube of the present invention.

FIG. 10 is a schematic diagram showing a situation in which heat is transferred from gas turbine exhaust to methanol fuel in the heating heat exchanger tube of the present invention.

FIG. 11 is a diagram showing a first structural example of an integrated heat exchanger according to the present invention.

FIG. 12 is a diagram showing a second structural example of an integrated heat exchanger according to the present invention.

FIG. 13 is a diagram showing a third structural example of an integrated heat exchanger according to the present invention.

FIG. 14 is a diagram showing a first structural example of an assembled heat exchanger according to the present invention.

FIG. 15 is a diagram showing a second structural example of an assembled heat exchanger according to the present invention.

FIG. 16 is a diagram showing a structural example of an integral type heat exchanger tube according to the present invention.

FIG. 17 is a diagram showing a structural example of an assembled heat exchanger tube according to the present invention.

FIG. 18 is a perspective view showing first to third examples of the assembled appearance of the integrated heat exchanger according to the present invention.

FIG. 19 is a perspective view showing a fourth example of the assembled appearance of the integrated heat exchanger according to the present invention.

FIG. 20 is a system diagram showing an example of a conventional combined power generation facility that recovers waste heat from gas turbine exhaust to drive a steam turbine.

FIG. 21 is a system diagram showing an example of conventional equipment that includes a fuel processing device in addition to a gas turbine and a steam turbine.

FIG. 22 is a system diagram showing an example of a fuel treatment process focusing on the flow of fuel using methanol as an example.

FIG. 23 is a diagram illustrating the balance between heat recovery and heat utilization in a fuel processing device.

[Explanation of symbols]

(C)
Compressor (CC)

Combustor (GT)
Gas turbine (GEN), (GEN1), (GEN2) Generator (
ST)
Steam turbine (COND)
Condenser (P), (P1), (P2
) Water supply pump (STC
K)
Chimney (HRSG)
Boiler, waste heat recovery boiler (LP-ECO)
Low pressure energy saver (LP-EVA)
Low pressure evaporator (
HP-ECO)
High pressure energy saver (HP-EVA)
High pressure evaporator (S
H)
Superheater (1-HPSH)
Primary high pressure superheater (2-HPSH)
Secondary high pressure superheater (1-HTR)
Primary heater (2-HTR)
Secondary heater (VHP-ECO)
High-pressure economizer (VHP-EVA)
High pressure evaporator (VHP-SH)
High pressure superheater (MeOH)
Liquid methanol, methanol fuel processing system (PRE-HTR)
Preheater (EVA)
Evaporator (HT
R)
Heater (REA)
Reactor (M
eSH)
Superheater (CATA)
Catalyst (a)

Gas turbine exhaust (b)
saturated water (d)

Heat medium (f)
Fuel, raw fuel (Gf)
Gas fuel, processed fuel (S)
Process side delivery steam (HP-S)
High pressure steam (LP-S)
Low pressure steam (Rs), (Rw)
Reaction steam, reaction water (HB), (SHB)
Bypass line (ET)
HRSG heat transfer tube (evaporation tube) (WT)
HRSG heat transfer tube (heating tube) (RT)
MeOH heat transfer tube (CT)
Downpipe (ED)

gas turbine exhaust duct

Claims (1)

[Claims] Claim 1. An apparatus for heating water to generate steam using a high-temperature waste heat source, and for performing fuel processing including evaporation of methanol fuel and a thermal decomposition reaction or a steam reforming reaction using the waste heat source, wherein the fuel A waste heat recovery device characterized in that a heat exchanger that performs at least part of the treatment is incorporated inside the heat exchanger that heats the water to generate steam.