JPH08261425A - Gasification of combustible waste, and melting method of ash - Google Patents

Abstract

PURPOSE: To utilize energy highly efficiently and recover valuable metals by a method wherein wastes are changed into distillated gas in a fluidized bed reaction device and the valuable metals are separated from generated solid residue while produced gas is burnt to recover energy. CONSTITUTION: Combustible waste is gasified in a fluidized bed reaction device 1 at 500-700 deg.C while HCl and H2 S are removed from produced gas by dry type treatment. Residue after the gasification is constituted of ash, carbon, iron and aluminum. Marketable metals such as iron, aluminum and the like remain on a hearth, carbon in the mixture of ash and carbon is accompanied by the produced gas and burnt together with the produced gas whereby the ash is molten at the temperature of 1000 deg.C or higher. Molten slag is crushed by water, then is disposed or utilized as aggregate. The exhaust gas of an ash melting furnace 2 is supplied to a gas turbine 4 to recover it as electric energy and the exhaust gas of the gas turbine 4 is utilized in a waste heat boiler 5 to heat feed water and generate steam while generated steam of 400 deg.C and 40kg/m<2> is supplied to a steam turbine.

Description

Detailed Description of the Invention

[0001]

[Industrial field of application] In the processing of flammable general waste and industrial waste, valuable materials such as iron and aluminum are recovered, and gas generated by dry distillation gasification of solidified ash and carbon Can be used as a roadbed material by burning, melting and solidifying, and the high-temperature combustion gas can recover energy to generate electricity and contribute to the prevention of global warming.

[0002]

2. Description of the Related Art At present, incineration is the main stream for the processing of combustible waste, but the following problems are present and further improvement has reached the limit.

Since the combustion gas of the waste is corrosive, the temperature of the steam is limited to 300 ° C., and the power generation efficiency is 10 to 15%. In addition, the consumption of ash and the exhaust gas treatment increase the consumption in the facility, and the practical energy recovery has reached the limit.

[0004] Exhaust gas treatment facilities have become complicated, resulting in increased cost and space.

Although ash melting is indispensable for environmental maintenance, power consumption is large in most processes.

Reduction and suppression of production of dioxins It is impossible to prevent a certain level of incineration and gas cooling, so a removal facility is required.

It is difficult to collect valuables

The incineration method which is currently the mainstream of waste treatment has the above-mentioned problems. The present invention solves the following problems.

[0008]

EFFECTS OF THE INVENTION Combustible waste is gasified by dry distillation at a temperature of 500 to 700 ° C., metals are separated from the generated solids, and the remaining residue is heated to 1000 ° C. or higher by combustion of dry distillation gas, and burned at high temperature. The energy recovery of the gas solves the following problems.

Increasing the efficiency of energy recovery The power generation efficiency, which is currently 15% or less, is raised to 25 to 35%.

Recovery of valuables It is possible to recover valuables such as iron and aluminum.

Melting and Solidification of Ash Ashes can be melted and solidified only by the energy of waste.

Formation of dioxins It is considered that the temperature rises to 1000 ° C. or higher due to the melting of ash and the hydrocarbon is carbonized to become inactive, so that the generation of dioxins is significantly reduced during the temperature lowering process of the gas.

[0013]

FIG. 1 shows a main part of an apparatus showing an embodiment of the method of the present invention. Figure 2 of the overall facility
Shown in The combustible waste is gasified at 500 to 700 ° C., and the gas is dry and HCL and H ₂ S are removed. Gasification residues are metals such as ash, carbon, iron and aluminum. Valuable materials such as iron and aluminum are entrained in the bottom of the furnace, and carbon in a mixture of ash and carbon is entrained in the generated gas and burns with the purified gas to melt the ash at 1000 ° C or higher. Molten slag is water granulated and either disposed of for final disposal or reused as aggregate. The exhaust gas of the ash melting furnace is generated by a gas turbine, and the exhaust gas of the gas turbine is heated by a waste heat boiler to heat feed water, generate steam, and heat steam, and is discharged to the atmosphere at 150 ° C. Occurred 400
The steam heated at 40 ° C / m ² is generated by a steam turbine and condensed by a condenser.

[0014]

Example: 1900 kcal / kg combustible waste 200T
/ D was treated, but the power generation amounts of the gas turbine and the steam turbine were 4640 kW and 1200 kW, respectively, and the power generation efficiency reached 30%. No gas turbine installed 1300
When the combustion gas at ℃ was put directly into the waste heat boiler and power was generated only by the steam turbine, power generation of 4870 kW was possible, and the power generation efficiency was 25%. Ash can be used as a roadbed material by granulating molten slag and discharging it. Iron scrap 6 tons / day and aluminum 2 tons / day were obtained from the furnace bottom.

[Brief description of drawings]

FIG. 1 is a flow chart showing a main part of a combustible waste gasification / ash melting method.

[Explanation of symbols]

 1 Fluidized bed 2 Jet bed 3 Air compressor 4 Gas turbine 5 Waste heat boiler

FIG. 2 is a flowchart showing a combustible waste gasification / ash melting system.

[Explanation of symbols]

 1 Gasification 2 Gas refining 3 Ash melting 4 Gas turbine 5 Steam turbine 6 Boiler heater 7 Condenser

Claims (2)

[Claims] 1. A method of treating combustible waste, wherein the combustible waste is subjected to dry distillation gasification at 500 to 700 ° C. in a fluidized bed reactor, and the solid residue generated separates valuable metals from metals.
Alternatively, a method of melting combustible waste gas and ash, characterized in that the gas generated by dry distillation gasification is melted at a temperature of 1000 ° C. or higher without being separated, and the energy of the high-temperature combustion gas is recovered. 2. A method for gasifying combustible waste and melting ash according to claim 1, wherein the ash is melted in an air flow reactor.