Ash melting furnace and method

Abstract

An ash melting furnace capable of a high-efficiency, stable operation and accommodating load variations, which is used for mixed melting for heating and melting main ash and flying ash as burned ash simultaneously, characterized in that main ash (coarse grain ash) in an upper layer and flying ash (fine grain ash) in a lower layer are supplied in layers from one end of the furnace body and heated and melted by a burner while being moved to the other end, whereby enabling the burner, when an oxygen enriched burner is used, to properly control an oxygen amount added to air (concentration change included) and, in response to a heated and melted ash condition caused by the combustion of the oxygen enriched burner, to properly control, in addition to fuel supply amount, an ash supply amount as required by a change in the oxygen enriching concentration.

Description

technical field [0001] This application is a divisional application of the invention patent application filed by Mitsubishi Heavy Industries, Ltd. on March 25, 1999, entitled "Ash Furnace and Its Ash Fusion Method" and application number 99800393.X. [0002] The present invention relates to a method for heating and melting the surface of the ashes of incineration ash, fly ash and other molten substances discharged from incinerators such as municipal garbage and industrial waste incinerators and coal-fired boilers, and using the molten ash as a molten Ash melting furnace with slag discharge and ash melting method thereof. Background technique [0003] There are incineration ash and exhaust gas in the discharge from waste incinerators such as municipal waste and industrial waste, and the wet ash obtained by recovering the above incinerated ash through the water sealing process and the dry ash obtained by recovering it in a dry state, respectively After crushing and magnetic s...

AI Technical Summary

Problems solved by technology

In addition, in order to discharge the exhaust gas containing a large amount of low boiling point substances, it is necessary to use a dust collector

And there will be such a problem: the nitrogen contained in the combustion air used in large quantities will generate NOx

[0015] Secondly, there is the problem of the slag pool 65 storing the molten ash 25 and the slag outlet 20 with a weir 23 on the outlet side.

[0016] That is to say, the weir 23 forming the above-mentioned slag pool 65 and the slag outlet 20 arranged on the weir, from Figure 21 It can be seen that the slag pool 65 is made into a substantially rectangular water storage pool, and the molten ash 25 stored in the rectangular slag pool 65 should be discharged from the slag outlet 20 arranged in the center, but the weir 23 side The movement of the molten ash 25 at the corners of the two squares is stagnant, and the stagnant part expands as the temperature drops, narrowing the flow path, and this is the cause of the decrease in the fluidity of the slag flow.

[0017] The 3rd problem is, the structural problem of propeller 58 that is arranged along furnace bottom 55

[0023] 1) The ash supply part 53 supplies ash from the ash storage part 60 to the furnace bottom entrance on one end side of the furnace bottom 55, which is carried out by the ash falling naturally by its own weight. However, in the process of falling, it will repeatedly cause bridging Phenomenon, so that the supply of ash cannot be carried out smoothly

[0024] 2) In addition, the ash falling on one end side of the furnace bottom 55 passes through the pusher 58 along the inclined surface of the furnace bottom 55, and is pushed out along the furnace bottom 55 to the discharge port 57 on the other end side of the furnace body, forming an ash supply layer. 59. However, since the movement of the pusher 58 is an intermittent reciprocating motion, the impact of the intermittent reciprocating motion on the ash particles with a small degree of engagement will attract and push the ash supply layer 59. The surface shape fluctuates sharply every time

As a result, even if the pusher 58 operates, the front end of the molten ash 25 cannot be moved forward by a necessary distance, so that the molten ash 25 cannot be slagged.

Sometimes, in front of the discharge port 57, the refractory material of the furnace bottom 55 will be exposed, causing overheating and erosion

[0026] In addition, in the latter case, as the melting progresses, the molten ash 25 flows out from the discharge side of the furnace bottom 55, and when the pusher 58 operates, the molten ash 25 will be generated downward due to the inertia of the supplied ash 50. Avalanche phenomenon, causing the unmelted ash 50 to flow out together with the molten ash 25, reducing the quality of the molten ash 25

[0027] That is to say, the problem of the above-mentioned angle of repose depends on the stable supply of the above-mentioned ash. Only in this way can the expected effect be achieved. The most important problem to be solved in the ash melting furnace is the stable supply of ash.

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