JP2002333120A - Method of presuming composition and lower calorific value of waste and waste disposal method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a waste disposal method solving a delay in the measurement of the composition of waste, estimating the composition and the lower calorific value of the charged waste from the gas composition obtained by the gasification of the waste and the composition of recovered matter and permitting the smoother treatment than conventionally by using the estimated value. SOLUTION: In a waste disposal method pyrolyzing, gasifying and melting waste to recover even a gas in addition to a metal and slag, the component element of the recovered gas is measured, and the composition of the charged waste is set by using the measured value, the quantity of recovered gas, the quantity of charged waste and the component and charge quantity of other charged matter to find the lower calorific value of the waste from the composition. In this case, respective 3 to 24-hour moving averages are desirably used for the measured value, the quantity of recovered gas and the quantity of charged waste.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for estimating the composition and low calorific value of waste, and a method for treating waste. More specifically, the present invention relates to gasification of waste and fuel gas containing hydrogen, carbon monoxide and the like. Or, in a waste treatment apparatus that recovers as a chemical raw material gas, relates to a technique for accurately estimating the composition and low calorific value of the waste to be treated and effectively utilizing the estimation result to smoothly treat the waste. .

[0002]

2. Description of the Related Art At present, industrial and general wastes (hereinafter simply referred to as wastes) have a remarkable shortage of disposal sites, and many of them have been generated as they are or have been subjected to some kind of pretreatment. Afterwards, final disposal such as landfill is often performed after volume reduction by incineration. Although the above incineration is performed by various methods, in recent years, from the viewpoint of management problems of harmful substances such as dioxin in generated gas at incineration plants and the viewpoint of resource recycling, not only incineration of waste but also fuel gas Alternatively, a technology for recovering as a chemical source gas has also emerged.

For example, as shown in FIG. 4, “Chemical equipment” (issued by the Industrial Research Institute, July 1998)
Is compressed and reduced in volume by a press 2, and then disposed with a pyrolysis furnace 3, a high-temperature reaction furnace 4, a homogenization furnace 5 for a melt, a gas cooling device 6, a gas purification device 7, a water treatment device 8, and the like. A pyrolysis gasification melting apparatus is disclosed. Also, JP-A-11-27
No. 0823 discloses a waste compression apparatus, a heating furnace for drying, pyrolyzing, and carbonizing a compression molded product, and a high-temperature reactor for producing a melt and a fuel gas from a carbonized product. A waste treatment facility in which a plurality of the heating furnaces are arranged for one vessel is proposed.

[0004] Generally, in such waste treatment, the composition of the waste varies widely, and even if the amount charged into the furnace is constant, the amount of heat supplied constantly varies. Therefore, the combustion state in the furnace always fluctuates,
Not only is the amount of gas generated (recovered) unstable, but also
The amount of fuel gas supplied to the furnace tends to be unnecessarily large, or the refractory of the furnace body tends to be greatly worn. Therefore, the amount of heat of the waste to be put into the furnace is sampled in advance and analyzed for its components, and the lower calorific value (true calorific value) of the waste is determined from the analysis result, or the moisture is measured immediately before the furnace, It is desirable to obtain a lower calorific value from the value and reflect it in the fuel supply in the operation. Incidentally, the lower heating value is represented by the following equation.

HL = Hh-25 (9h + w) where HL: low calorific value of waste (kJ / kg-wet waste) Hh: high calorific value (total) calorific value of waste (kJ / kg-wet waste) ) H: Hydrogen content in wet waste (%) w: Moisture in moisture waste (%) In addition, the heat balance is calculated for the entire waste treatment equipment, and the difference between heat output and heat input is calculated as heat generation of waste. There is also a method of obtaining a lower heating value as an amount.

However, in the above-mentioned sampling method, it is questionable whether it takes a long time to obtain a result or whether a representative value of waste is obtained by sampling. Also, in the method of measuring moisture, there is a problem in the measurement accuracy, the method using the heat balance is the most influential method, but uses data averaged over a certain long time, so it is actually in the furnace There is a problem that it shows the past low calorific value that has already burned rather than waste. Therefore, Japanese Patent Application Laid-Open No. 55-160219 proposes a method for obtaining the quality of waste and the lower calorific value of the waste from the flow rate, the composition, and the amount of input air of the waste gas in the waste incinerator.

However, this proposal is a method for a refuse incinerator, and when the incinerator is a stalker furnace, it is difficult to measure the moisture in the exhaust gas, and the amount of leaked air is large, so that the amount of air can be accurately grasped. It is difficult to do
0-185157). In addition, since the amount of exhaust gas is large relative to the amount of waste and the accuracy is low, it is currently not actually used.

[0008]

SUMMARY OF THE INVENTION In view of the above circumstances, the present invention eliminates the delay in the measurement of the composition of waste and, based on the gas composition obtained by gasification of waste, calculates the composition and An object of the present invention is to provide a waste disposal method that estimates a lower heating value and uses the estimated value to enable smoother treatment than before.

[0009]

Means for Solving the Problems The inventor has conducted intensive studies in order to achieve the above object, and has embodied the results in the present invention.

That is, according to the present invention, in waste treatment in which waste is pyrolyzed, gasified, and melted to collect gas in addition to metal and slag, the concentration of the constituent elements of the collected gas is measured. The composition of the charged waste is determined by using the measured values, the amount of the recovered gas, the charged amount of the waste, and the components and the charged amount of the other charged substances. This is a method for estimating the composition of waste and the lower calorific value, which is characterized by calculating the calorific value. In this case, the measured value, the recovered amount of the gas, and the charged amount of waste are respectively 3
It is preferable to use a moving average value of up to 24 hours.

Other materials to be charged are fuel gas, high concentration oxygen,
Preferably it is nitrogen.

Further, the present invention calculates the amount of heat loss from the gasifier using the lower heating value of the waste obtained by the above estimation,
The waste gas is treated while adjusting the repair time of the gasifier based on the change over time of the heat loss amount, or the recovered gas is burned based on the composition of the recovered gas determined by the measured value and the recovered gas amount. The waste heat treatment method is characterized in that the calorific value at the time is obtained, and the amount of fuel gas supplied to the gasifier is adjusted so that the calorific value is always within a certain range.

According to the present invention, the composition of the charged waste can be estimated, the lower heating value of the waste can be estimated by calculation from this composition, and the heat balance of the gasification furnace can be calculated. As a result, the amount of fuel gas supplied to the gasification furnace can be optimized, and the furnace body management of the gasification furnace can be performed more smoothly than before.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

According to the present invention, waste is compressed and reduced in volume, and then sequentially passed through a pyrolysis furnace, a high-temperature reactor, a melt homogenization furnace, a gas cooling device, a gas purification device, a water treatment device, and the like. The present invention is effectively applied to, for example, the process shown in FIG. 4 for recovering gas as well as slag and metal. Therefore, the gasification furnace referred to below includes a pyrolysis furnace, a high-temperature reaction furnace, and a homogenization furnace for a molten material (assumed to be integrated).

First, the composition of the charged waste is converted to gas
Materials in furnaces, gas purification equipment (cooling equipment) and water treatment equipment
Estimate from balance. The whole picture is as shown in Fig. 1.
Can be organized. In FIG. 1, the entry and exit directions to and from the target device are indicated by →.
Indicate the charge and discharge to and from the device.
As well as underlining the material underneath,
Measured during operation or shown to be known
I have. (1) The ash content of waste is the ash content of waste P = (recovered slag amount)S+ Amount of recovered metal
M) / Waste chargeW _I Is required. In addition, the amount of each composition contained in the waste
Is determined by the following (2) to (7). (2) The amount of hydrogen contained in waste is as follows: Waste hydrogen amount H = Hydrogen amount in recovered gasH _G−Water in fuel gas
Elementary quantityH _F+ Recovered condensate hydrogen amountH _W(3) The amount of oxygen contained in the waste is as follows: waste oxygen amount O = oxygen amount in recovered gasO _G-Acid in fuel gas
Elementary quantityO _F-Oxygen content in high concentration oxygenO _H+ Oxygen content in recovered condensed water
O _W (4) The amount of nitrogen contained in the waste is as follows: Waste nitrogen amount N = Nitrogen amount in recovered gasN _G-In high oxygen concentration
Nitrogen contentN _H-Nitrogen chargeN _I (5) The amount of carbon contained in waste is the amount of carbon in waste C = the amount of carbon in recovered gasC _G-Coal in fuel gas
Elementary quantityC _F (6) The amount of sulfur contained in waste is as follows: waste sulfur amount S = recovered sulfur amountS _O (7) The amount of chlorine contained in the waste is the amount of chlorine in the waste Cl = the amount of chlorine in the recovered mixed saltCl _O-In hydrochloric acid
Chlorine amountCl _I (8) The amount of condensed water collected is the amount of condensed water W_W= Waste amountW _I+ Fuel gas volumeF+ High concentration oxygen
Medium oxygen contentO _H+ Nitrogen content in high concentration oxygenN _H+ Nitrogen chargeN _I
−Recovered gas volumeG-Amount of recovered slagS−Amount of recovered metalM Therefore, the amount of each element described in (1) to (7) is calculated.
Then, the composition of the waste is determined according to the measurement time.
Also, the recovered condensed water amount W_WIs determined by equation (8). In addition,
The amount of each substance entering and leaving the gasifier and the composition of the recovered gas are as follows:
Both are measured every minute and are sent to a computer as data.
And memorize it. Waste charge W_IIs the charging time and quantity
Is stored. And, in the present invention, before these data
The calculation was performed after performing the processing appropriately. That is,
Every time the measurement is performed, the composition may be estimated.
However, for each data, an average value was calculated for one hour, and 3 to 24
It is preferable to use it as a so-called "moving average" of time
No. Does it match the actual operation because it is averaged?
It is. If the moving average time is less than 3 hours,
The timing of waste loading is averaged due to the residence time of
Over 24 hours, feed to operation
Since backing is not possible, inconvenience occurs. Therefore, the book
In the invention, 3 to 24 hours are adopted. Further
The amount of condensed water recovered is determined by measuring the amount of condensed water.
Thus, it can be calculated.

The recovered gas is composed of hydrogen, carbon monoxide, carbon dioxide, nitrogen, moisture, and a small amount of methane. The amounts of these components can be easily measured by high performance gas chromatography or infrared gas analyzer.

Next, a method for determining the lower heating value of the waste by using the composition of the waste determined as described above will be described.

Therefore, first, it is assumed that the waste consists of three components of ash, moisture and combustible. Then, from the composition of the waste obtained as described above, the carbon ratio in the combustibles is assumed (in the case of general waste, about 50% is assumed), and the moisture in the waste is calculated by the following equation. .

Water content = ((1 / carbon content) − (1 / carbon content basis)) / (1 / carbon content) × (1−ash content) Is calculated (1-moisture-ash content). Subsequently, by subtracting the moisture from each element amount in the waste obtained by the calculations in the above (2) to (7), the true element amount (carbon, oxygen, hydrogen, sulfur, chlorine, etc.) in the combustibles is obtained. Can be requested.

By substituting the true elemental amount of the waste thus obtained into, for example, the Steuer's equation which is said to relatively match the true value in the case of municipal garbage, the higher heating value of the waste can be obtained. (Total calorific value) is obtained. (9) Steuer's formula
Design Guideline "(National Cleaning Council) (1999) p145
Hh = 339.4 {c-3 × (o / 8)} + 238.8
× 3 × (o / 8) +1445.6 {h− (o / 16)}
+104.8 s [kJ / kg] Here, c, h, o, and s are mass% of carbon, hydrogen, oxygen, and sulfur, that is, the true element amounts described above.

Therefore, by substituting the higher calorific value into the following equation for calculating the lower calorific value, the lower calorific value of the waste can be easily determined.

HL = Hh-25 (9h + w) where HL: low calorific value of waste (kJ / kg-moist waste) Hh: high calorific value (total) calorific value of waste (kJ / kg-moist waste) H: hydrogen content in wet waste (%) w: moisture in wet waste (%) Next, in the present invention, the lower calorific value of the waste obtained by the above estimation is effectively used for furnace operation. I thought about doing it. That is, since the heat loss in the gasifier is obtained by the following equation, the degree of damage to the refractory lining the furnace body can be estimated by observing the change over time in the heat loss of the gasifier. . Specifically, when the frequency of high heat loss frequently occurs, the time to perform the furnace repair is increased, and in the opposite case, the time to perform the furnace repair is delayed. This makes it possible to manage the furnace body more smoothly than before. Heat loss of gasifier = lower calorific value of waste + lower calorific value of fuel gas-lower calorific value of recovered gas-sensible heat of gas at outlet of gasifier The lower calorific value of recovered gas and gas in the above equation The sensible heat at the outlet of the gasifier can be easily determined by obtaining a normal heat balance in the gasifier.

Further, in the present invention, reduction of fuel gas to be supplied to the gasification furnace was considered. This is because the composition of the recovered gas is easily determined by the measured value and the recovered gas amount. That is, the calorific value when the recovered gas is burned is determined from the composition, and the amount of the fuel gas supplied to the gasifier is adjusted so that the calorific value is always within a certain range. As a result, an excessive supply of fuel gas can be prevented, and economic operation can be achieved.

In the present invention, the range of the calorific value is 4.186 × 10 ³ when power is generated by a gas engine.
It is preferably at least kJ / m ³ (1000 kcal / m ³ ). 4.186 × 10 ³ kJ / m ³ (1000 kc
If the amount is less than (al / m ³ ), the calorific value is too low, which causes a problem in the power generation of the recovered gas by the gas engine.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is applied to the operation of the waste disposal apparatus shown in FIG. The amount of waste is about 6 tons / hour.
Other main operating conditions are as shown in Table 1. During this operation, the gas composition, gas volume, and the amount of each substance recovered were measured every minute, and at the same time, the data was processed by a computer to estimate the composition of the recovered gas and the lower heating value, and the results were obtained. It is shown in Table 2. Table 2 shows the results obtained by using an 8-hour moving average value.

[0027]

[Table 1]

[0028]

[Table 2]

At the same time, the heat loss and the calorific value of the recovered gas were also calculated, and their changes with time are shown in FIGS. The operation was performed while the operator took an operation action while monitoring the heat loss in FIG. Also, the calorific value of the recovered gas is always 4.186 × 10 ³ kJ / m ³ (100
0 kcal / m ³ ) or more (see FIG. 3), the amount of supplied fuel gas (LNG) was also adjusted.

As a result, the fuel gas amount could be reduced to one third of the conventional one, the life of the furnace body could be extended, and the rate of increase in heat loss was reduced by 30%.

[0031]

As described above, according to the present invention, not only slag and metal are recovered from waste but also gas is recovered as fuel gas. The composition of the charged waste can be estimated, the lower heating value of the waste can be estimated by calculation from this composition, and the heat balance of the gasifier can be calculated. As a result, the amount of fuel gas supplied to the gasification furnace can be optimized, and the furnace body management of the gasification furnace can be performed more smoothly than before.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a material balance of a gasification furnace on which the present invention is based.

FIGS. 2A and 2B are graphs showing changes over time in heat loss and fuel gas consumption of a gasifier obtained by applying the present invention, wherein FIG. 2A shows heat loss and FIG. 2B shows fuel gas consumption.

FIG. 3 is a diagram showing a change over time in a calorific value of a recovered gas.

FIG. 4 is a flowchart showing a waste pyrolysis gasification / melting apparatus to which the present invention is applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Waste 2 Press 3 Pyrolysis furnace 4 High temperature reactor 5 Homogenization furnace 6 Gas cooling device 7 Gas purification device 8 Water treatment device

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Taro Kusakabe 2-3-2 Uchisaiwai-cho, Chiyoda-ku, Tokyo Kawasaki Steel Corporation (72) Inventor Hiroyuki Sugiura 2-3-2 Uchisaiwai-cho, Chiyoda-ku, Tokyo F term in Saki Steel Co., Ltd. (reference) CC02 DA02 DA10 DA11 DA20

Claims (4)

[Claims] 1. Pyrolysis, gasification and melting of waste,
In waste treatment, which collects gas in addition to metal and slag, the concentration of the constituent elements of the recovered gas is measured, and the measured values, the amount of recovered gas, the amount of waste charged, and other charges A method for estimating the composition and low calorific value of a waste, comprising determining the composition of the charged waste using the components and the amount of the substance charged, and calculating the low calorific value of the waste from the composition. 2. The waste composition and low-grade material according to claim 1, wherein a moving average value of 3 to 24 hours is used for each of the measured value, the gas recovery amount, and the waste charge amount. Estimation method of calorific value. 3. The amount of heat loss from the gasifier is calculated using the lower heating value of the waste obtained in claim 1 or 2, and the time of repair of the gasifier based on the change over time in the amount of heat loss. A waste treatment method, wherein the waste treatment is performed while adjusting the temperature. 4. A calorific value when the recovered gas is burned is determined from the composition of the recovered gas determined by the measured value and the amount of the recovered gas, and the gasification furnace is controlled so that the calorific value is always within a certain range. A waste disposal method comprising adjusting an amount of fuel gas to be supplied.