JPH0678540B2 - Method and apparatus for supplying char to gasifier - Google Patents

Description

TECHNICAL FIELD The present invention relates to a system for recycling char generated in a gasifier for producing gas fuel from coal to the gasifier. More specifically, the present invention relates to a char feeding method and apparatus for keeping the amount of char recycled to the gasification furnace appropriately.

(Prior Art) In recent years, coal gasification combined cycle power generation has been attracting attention in Japan and overseas as a new coal utilization technology with high efficiency and excellent environmental protection. What is combined gasification combined cycle power generation? Coal gasification combined power generation gasifies coal in a gasification furnace, desulfurizes and dedusts it with a gas purifier, and then combusts it in a gas turbine combustor to generate power in a gas turbine and at the same time generate steam from its exhaust heat. It is a method of generating and generating electricity with a steam turbine.

By the way, in the realization of such a combined cycle power generation system, the coal gasification technology is one of the most important technical issues. Coal gasification is roughly divided into two processes: pyrolysis of coal and subsequent gasification of char (main components are unburned carbon and ash). Pyrolysis reacts in a relatively short time as the temperature rises, but the gasification reaction of the char generated at that time is slow, so how to efficiently incorporate this char into the gasification process is an important issue. In the gasification furnace, maximum efficiency is exhibited when the entire amount of the char, that is, the generated char, that has come out of the gasification furnace is supplied to the combustor.

Therefore, the conventional experimental furnace is provided with a recycling facility for collecting the char carried out of the gasification furnace 101 together with the generated gas and recharging the char to the combustor of the gasification furnace. The generated char is collected by the cyclone 102, and the dust collecting hopper 108, the lock hopper 103, and the weighing hopper 104.
Then, a predetermined amount is taken out by the table feeder 105 and the distributor 106
Is supplied to each burner. Here, the char supply amount is operated with the target value being the amount received by the weighing hopper 104 from the indicated value of the load cell 107 conventionally attached to the weighing hopper 104.

(Problems to be Solved by the Invention) However, according to the conventional char supply method, the absolute target value of the char amount to be supplied in order to maximize the performance at the operating air ratio cannot be known during operation.
That is, this is because the amount of char received by the weighing hopper does not necessarily correspond to the amount of char generated due to the influence of fluctuations in cyclone efficiency and payout between hoppers. If the cyclone efficiency is stable and the payout between the hoppers is good, then the amount of char received and the amount of char produced will correspond. However, even if the air ratio is the same, the generated char amount changes depending on the char supply amount.Therefore, if the char supply amount is changed at the target of the amount received by the weighing hopper at a certain point, the generated char amount will change at the next point. The amount of chars supplied to the weighing hopper will change accordingly, and the char supply must be changed with the target of the amount of chars received. That is, there is a problem that the target value for supplying the generated char amount without excess or deficiency is not clear.

At present, this gasifier is in the basic experiment stage, so there are few problems with the char supply equipment as described above, but in order to realize efficient operation of the gasifier prior to commercialization of the gasifier. , Establishment of an appropriate char supply system to the gasifier is desired.

The present invention aims to establish a system capable of determining an appropriate char supply amount when recharging the recovered char to the gasifier in the operation of a gasifier that obtains gas fuel from coal, and specifically, an appropriate amount. It is an object of the present invention to provide a method and a device for supplying char.

(Means for Solving the Problem) In order to achieve the above object, the char supply method for a gasification furnace of the present invention obtains the amount of air supplied to the gasification furnace and the amount of pulverized coal, and supplies the supplied air amount and supply. Calculate the calorific value of the generated gas when all the char generated based on the amount of pulverized coal is re-introduced into the gasification furnace, and calculate the calorific value of the generated gas with respect to the calorific value of the generated gas relative to the air ratio in the furnace collected in advance. The amount of char produced is estimated by comparing with the experimental data showing the relationship of the theoretical air amount of char to the air ratio in the furnace, and the same amount of char is supplied to the gasification furnace.

Further, the char supply device of the gasification furnace of the present invention is a gasification furnace, means for measuring the amount of air and the amount of pulverized coal supplied to the gasification furnace, and the outside of the furnace together with the produced gas from the gasification furnace. Means for collecting the char to be carried out to, a means for storing the collected char, a supplying means for extracting a predetermined amount of the char from the storing means to the gasification furnace, and a gas obtained by the measuring means A means for calculating the calorific value of the generated gas when all the char generated based on the amount of air supplied to the gasification furnace and the amount of pulverized coal is re-introduced into the gasification furnace, and the calorific value of the generated gas is collected in advance. Means for estimating the generated char amount by comparing with experimental data showing the relationship between the generated gas calorific value with respect to the furnace air ratio and the char theoretical air amount with respect to the furnace air ratio, and controlling the supply means with the same amount of char And then And a control means for supplying the gasification furnace.

(Operation) Therefore, if the amount of pulverized coal and air to be supplied to the gasification furnace is determined, the calorific value of the generated gas when the total amount of char generated therefrom is reintroduced into the gasification furnace is determined,
The in-reactor air ratio was estimated by comparing it with experimental data showing the relationship between the collected gas heat value for the in-reactor air ratio and the char theoretical air amount for the in-reactor air ratio, and The char theoretical air amount is further estimated from the air ratio, and then the generated char amount is estimated.

(Example) Hereinafter, the structure of the present invention will be described in detail based on an example shown in the drawings.

FIG. 1 shows an embodiment of a char supply device for a gasification furnace according to the present invention. This char supply device includes a gasification furnace 1, means 2 and 3 for measuring the amount of air and the amount of pulverized coal supplied to the gasification furnace 1, and a char carried out from the gasification furnace 1 together with the produced gas. The means 4 for collecting, the means 5 for storing the recovered char, the supply means 6 for extracting the char from the storing means 5 to the gasification furnace 1, and the gasification furnace 1 obtained by the measuring means 2, 3 Means 7 for calculating the calorific value of the generated gas when all the char generated based on the supplied air amount and the pulverized coal amount is re-introduced into the gasification furnace, and the furnace in which the calorific value of the generated gas is collected in advance. Means 8 for estimating the amount of generated char by comparing with experimental data showing the relationship between the calorific value of generated gas with respect to the internal air ratio and the theoretical air amount of char with respect to the in-furnace air ratio, and controlling the supply means 6 with the same amount of char Control means for supplying to the gasification furnace 1 It is composed of a.

As the gasification furnace 1, for example, a two-stage spouted bed gasification furnace is adopted. This gasification furnace 1 comprises a combustor section 1a for burning coal and char at high temperature, a diffuser section 1b for completely mixing coal and high temperature gas rising from the combustor to promote coal carbonization and thermal decomposition, and a char. And a reducer section 1c for performing gasification.

As the means 2 and 3 for measuring the amount of air supplied to the gasification furnace 1 and the amount of pulverized coal, for example, a load cell or a flow meter is used. For example, the load cell 2 is attached to the hopper 10 that stores the pulverized coal fuel, and the amount of pulverized coal supplied is measured from the change in the weight of the hopper 10. Further, the flow meter 3 is provided in the air supply pipeline 15 so as to measure the amount of supplied air and output it as an electric signal. The pulverized coal is pneumatically transported by the air supplied from the air supply blower 16.

Further, as the collecting means 4, for example, use of a cyclone or the like is suitable. Further, it is preferable to use a lock hopper or the like as the storage means 5. Further, as the char supply means 6, for example, a calculation hopper 11 for receiving the char once stored in the lock hopper 5, a table feeder 12 for taking out the char from the weighing hopper 11 under the control of the control means 9, and a take-out by the table feeder 12. It is configured by a char distributor 13 that conveys the formed char to the combustor 1a of the gasification furnace 1 by air flow. The char distributor 13 has, for example, a perforated plate at the bottom thereof, and conveys the char to the char supply pipe while maintaining the char in a fluid state by the conveying gas blown from the perforation. Although air may be used as the carrier gas, it is preferable to use a gas obtained by extracting a part of the produced gas that has passed through the cyclone 4 with the blower 14. Reference numeral 17 in the drawing is a load cell.

Further, means 7 for calculating the generated gas calorific value, means 8 for estimating the generated char amount, and control means 9 for controlling the supply means.
Is composed of a well-known computer and a program for operating the computer. The computer is basically a central processing unit (CP
U) and a ROM and RAM in which a program is written, and a table feeder of each of the measuring means 2 and 3 and the char supplying means 6 to be controlled through the interface.
12 which is electrically connected to 12 and operates according to a program written in the ROM to calculate the generated gas calorific value, and functions as a means 8 for estimating the generated char amount and a controller 9 for controlling the supply means 6. .

With the above structure, an appropriate amount of char is reintroduced into the gasification furnace as follows.

First, the amount of air supplied to the gasification furnace and the amount of pulverized coal are obtained by the measuring means 2 and 3. Then, the generated gas calorific value when the char generated based on the supplied air amount and the supplied pulverized coal amount is recharged into the gasification furnace is calculated by the generated gas calorific value calculation means 7. Then, the generated char amount is estimated by the estimation means 8 by comparing the generated gas calorific value with experimental data showing the relationship between the collected gas calorific value with respect to the in-reactor air ratio and the char logical air amount with respect to the in-reactor air ratio collected in advance. To do.

There is a linear constant relationship between the in-reactor air ratio and the generated gas calorific value, which is expressed as HHV = a ₁ λm + b ₁ … (1), and the char theoretical air amount for the in-reactor air ratio is Achar = A ₂ λm + b ₂ (2) Therefore, experimental data showing the relationship between the in-furnace air ratio and the generated gas calorific value, and the in-reactor air ratio and the char theoretical air amount are accumulated in advance, and the above-mentioned relationship is calculated from these data by the equations (1) and (2) If it is stored in, the furnace air ratio can be obtained from the calorific value of the generated gas. Further, the char theoretical air amount can be calculated from the in-furnace air ratio in the same manner from the equation (2). And these are defined as the air ratio in the furnace, The amount of char is calculated by substituting into Therefore, the same amount of char as the calculated amount of char is taken out from the storage means 5 and supplied to the gasification furnace 1.

Hereinafter, the operation of the above-mentioned proper char supply amount determination system will be described in more detail based on the flowchart shown in FIG.

First, using the gasification furnace 1 and the char supply device, experimental data showing the relationship between the calorific value of the produced gas with respect to the air ratio in the furnace and the char theoretical air amount with respect to the air ratio in the furnace were collected in advance, (1), It is stored in the computer as the relational data of the equation (2). In addition, various data such as pulverized coal input properties, input air properties, gasification furnace furnace wall heat absorption amount, and exhaust slag amount are input (step 21). At this time, the properties of the coal and the properties of the air are known in advance, so it suffices to input them once into the computer and store them. Also, the gasification furnace wall endotherm,
The data on the amount of discharged slag is necessary when calculating the calorific value of the generated gas when the char is completely recharged.

Next, the amount of pulverized coal input and the amount of input combustion air are measured by measuring means 2, 3
Is input from time to time (step 22), and the air ratio is calculated (step 23). Then, the generated gas temperature Tg for calculating the generated gas calorific value is assumed (step 24). Then, the C, H, O balance and the shift reaction are calculated based on this assumed product gas temperature Tg, and the property of the product gas is calculated (step 5). This C, H, O balance, ft reaction calculation is C balance C in input pulverized coal = CH balance of CO and CO ₂ in produced gas H in input pulverized coal, H in air = H ₂ , H ₂ O in produced gas of H O balance turned coal, air O = CO in the product gas, CO _2, H ₂ O in O shift reaction (However, C ₁ , C ₂ , C ₃ , C ₄ are constants), and the properties of the produced gas under the gas temperature Tg are calculated (step 25).

Next, in the properties of the generated gas described above, the generated gas temperature Tg ′ is obtained from the viewpoint of heat balance (step 2
6). This heat balance calculation is carried out with the sensible heat of the produced gas in order to balance the chemical heat of coal input, sensible heat + sensible heat of input air = chemical heat of generated gas, sensible heat + gasification furnace wall endothermic amount + slag sensible heat. The temperature of the produced gas is newly calculated by using heat, that is, the temperature component as an unknown number.

Then, the product gas temperature Tg ′ and the assumed product gas temperature Tg
It is determined whether the absolute value of the difference between and is larger or smaller than a certain value c (step 27). If the value is large, the process jumps before step 4 and the above calculation is repeated with Tg 'as the assumed temperature Tg (step 28). When the above value is smaller than ε, the property of the produced gas at that time is specified as a true value. Then, the calorific value of the gas is calculated from the properties of the generated gas (step 29).

Next, the in-reactor air ratio λm ₁ is determined from the generated gas heat value by comparing with experimental data showing the relationship between the in-reactor air ratio and the generated gas heat value and the char theoretical air amount.
That is, the in-furnace air ratio λm ₁ is calculated from the calorific value of the generated gas according to the equation (1) (step 30). Then, the char theoretical air amount Achar when the in-furnace air ratio λm ₁ is calculated from the equation (2) (step 31). Then, the char amount is further calculated from the equation (3) showing the definition of the air ratio in the furnace (step
32). The char amount thus obtained is displayed on the operation control panel or the like, or is output as a control signal for the char feeding device (step 33). For example, the char feeding device 6
It is used as a control signal for the table feeder 12 of No. 1 and recharges an appropriate amount of char to the combustor 1a of the gasification furnace 1 in accordance with the pulverized coal amount and the supply air amount that change from time to time to improve the maximum efficiency. It can be driven automatically.

(Effects of the Invention) As is apparent from the above description, according to the present invention, if the amounts of pulverized coal and air supplied to the gasification furnace are obtained, the entire amount of char produced therefrom is re-introduced into the gasification furnace. The calorific value of the generated gas at the time of is calculated, and by comparing it with the experimental data showing the relationship between the calorific value of the generated gas with respect to the in-reactor air ratio collected in advance and the char theoretical air amount with respect to the in-reactor air ratio, The furnace air ratio is estimated, and the char theoretical air amount is further estimated from this furnace air ratio, and the generated char amount is then estimated.Therefore, the absolute target value of the char amount to be charged, which changes from time to time, is supplied. It can be calculated immediately from the amount of coal and the amount of air supplied. Therefore, if the char supply facility is operated with this generated char amount as an absolute target value, maximum efficiency can be obtained in the gasification furnace.

[Brief description of drawings]

FIG. 1 is a diagram corresponding to the claims of the present invention. FIG. 2 is a flow chart for explaining the supply amount determination process of the char feeder according to the present invention. FIG. 3 is a schematic diagram showing a conventional char supply facility. 1 ... Gasification furnace, 2, 3 ... Measuring means, 4 ... Recovery means, 5 ... Storage means, 6 ... Char supply means, 12 ... Table feeder for controlling char supply amount, 7 ... Generation Gas calorific value calculating means, 8 ... Generated char amount estimating means, 9 ... Control means.

Claims (2)

[Claims] 1. An amount of air supplied to a gasification furnace and an amount of pulverized coal are obtained, and all chars generated based on the supplied air amount and the amount of supplied pulverized coal are recharged to the gasification furnace. The generated gas calorific value is calculated, and the generated gas calorific value is compared with experimental data showing the relationship between the collected gas calorific value with respect to the in-reactor air ratio and the char theoretical air amount with respect to the in-reactor air ratio collected in advance. Is estimated and the same amount of char is supplied to the gasification furnace as a char supply method. 2. A gasification furnace, means for measuring the amount of air and the amount of pulverized coal supplied to the gasification furnace, and means for collecting char carried out of the gasification furnace together with the produced gas outside the furnace. A means for storing the recovered char, a supply means for extracting the char from the pre-storage means and supplying the char to the gasification furnace,
A means for calculating the generated gas calorific value when the total amount of char generated based on the amount of air supplied to the gasification furnace and the amount of pulverized coal determined by the measuring means is re-input to the gasification furnace, A means for estimating the generated char amount by comparing the generated gas calorific value with experimental data showing the relationship between the collected gas calorific value with respect to the in-reactor air ratio and the char theoretical air amount with respect to the in-reactor air ratio collected beforehand A char supply device for a gasification furnace, comprising: a control means for supplying a quantity of char to the gasification furnace by controlling the supply means.