Application of the most popular German Martin furn

The use of German Martin row electric incineration equipment in garbage incinerators

with the continuous improvement of the development level of urbanization in China, people produce a large amount of garbage every day. How to better deal with and recycle these garbage has become a major problem perplexing social development. This paper will discuss the application of German Martin grate electric incineration equipment in waste incinerators, and deeply explore how the automatic combustion control system regulates and controls the steam flow, grate action speed and air supply volume in the process of waste incineration

preface

for the waste treatment plant in the city, the amount of waste to be treated every year is very large, so we need to pay special attention to the effect of waste incineration. This paper selects the German Martin grate treatment technology, which can realize the full automatic process management of waste incineration and greatly improve the safety of electric incineration equipment

I. overview of German Martin grate

German Martin grate technology is the most widely used and most effective waste incinerator technology in the world, especially in countries with relatively high waste emissions, which can be said to have been widely used. As shown in Figure 1, it is a schematic diagram of the use effect of German Martin grate. The length of German Martin grate is relatively fixed, and the width will be adjusted with the area of the hearth, which can be formed by horizontal combination of many hearth. Specifically, each hearth will contain 13 fixed and movable stepped grate bars. The fixed grate bars and movable grate bars are horizontally staggered, and the hearth is an inclined bed surface with an inclined angle of 26 °

generally, the drying and combustion of incinerated waste can be carried out in the Martin grate hearth, and the air will be blown into the furnace from the bottom of the hearth through the air trough of the grate and then from both sides of the grate. Among them, the movable grate is composed of a connecting rod and a beam, which is driven by a hydraulic transmission device. Its moving speed can be adjusted, and it can also cooperate with various combustion conditions to drive the movable grate to move in the opposite direction by means of garbage mixing, so that the garbage can slide down due to gravity, and then the burned ash will be transferred to the ash discharge trough by means of ash roller transfer [2]

Figure 1 effect diagram of German Martin grate

II. Waste incineration process flow

when the waste enters the unloading platform, it needs to go to the waste pool through the unloading door, and then use the waste crane to pour the waste into the German Martin grate. By controlling the primary air volume of the grate electric incineration equipment, the gas control of the grate, auxiliary ignition and the flue gas temperature in the furnace are controlled above 850 ℃, At the same time, it is necessary to spray leachate back into the incinerator to reduce the emission value of flue gas. By spraying urea, the combustion furnace can be denitrated, so that the steam generated by the incineration boiler can drive the steam turbine to generate electricity and complete the incineration of garbage

III. working principle of German Martin grate electric incineration equipment

the control system of German Martin grate electric incineration equipment is mainly composed of garbage hopper, feeder, movable grate, fixed grate, furnace and slag hopper, slag chute, slag extractor, air combustion system and hydraulic drive device. Generally, the German Martin grate electric incineration device used by waste incineration plants in China is a reverse push reciprocating grate, The maximum stroke of the grate is 420mm. The grate can be divided into drying area, combustion area and burnout area. Garbage needs to pass through the drying area first, and tumble evenly in the drying area, so that it can be fully burned in the combustion area, and then to the burnout area, and the ash can be discharged through the slag roller. The primary combustion air can enter the incineration furnace at the air hole between the two furnace sheets through the air duct at the bottom, so that the air can support the combustion of garbage and cool the grate sheets. The two adjacent grate sheets should move relatively to ensure that the air hole will not be blocked by slag material [3]

IV. the use of German Martin row electric incineration equipment in garbage incinerators

(I) automatic combustion control system

the use of German Martin row electric incineration equipment in garbage incinerators in garbage plants, for the flow control of incineration steam and the combustion of incineration furnace to the measured spring afterburning temperature control is mainly for the operation of feeder and grate, The project involves the aerospace company Diehl aerospace, which can directly control the total amount of garbage entering the incinerator. The automatic combustion control system is an important part of the waste incinerator. The incineration capacity cannot exceed the rated value of the incinerator. Through the steam mode of waste heat boiler, adjust and control the speed of the feeder, the running speed of the grate and the combustion air volume, so as to ensure the good combustion condition of the incinerator, control the temperature of the furnace and the heat reduction rate, so as to effectively ensure that the emission condition of waste incineration meets the environmental protection regulations, To ensure the stability of incinerator waste incineration and the economic benefits of waste power generation, therefore, the automatic control system of German Martin furnace exhaust electric incineration equipment mainly adopts the continuous control mode of steam flow, which is completed in the combustion control loop [4]

(II) grate combustion system

1 Start stop control

start stop control mainly refers to the furnace temperature control of the waste incinerator in the start-up stage and stop stage, that is, to make the deviation value DV between the process value PV and the set value SV greater than the upper limit of 2%. For the setting of the deviation value of steam flow and furnace temperature, it can be completed by the action design of the feeder or Martin furnace row. If the steam flow needs to pass through the lower limit during the rising process, At this time, if the grate action is "closed", the rising action stops, and the steam flow and the furnace temperature of waste incineration will also begin to drop. If it crosses the upper limit area in the process of falling, and the action of the Martin furnace row needs to be changed to the "on" state, then the steam flow and furnace temperature will rise at this time. If the steam flow passes through the upper limit value in the rising direction, the action signal of the grate is "off" at this time, and the action signal of the grate passes through the lower limit value in the falling direction, and the action signal of the grate is "on". This way of start-up and stop control belongs to the forward flow control, which is finally expressed by people in the industry. In addition, the differential value of steam flow deviation DV can also be controlled according to the phase advance method, and the advance control method can be adopted to speed up the action response speed of fuel engine and Martin furnace exhaust [5]

2. Speed control

during the operation of the anchor fatigue testing machine, 1 must pay attention to whether the parts are loose

the speed control of the grate combustion system mainly refers to that under the normal operation state of the waste incinerator, the steam flow value is better matched by controlling the speed of the steam flow, and the remote computer DCS control system is used to obtain the series signal of the operation of the feeder and the grate. If it is not the series control, It is necessary to compare the action speed of the grate with the given combustion speed of the incinerator. If the running speed of the grate is relatively large, it needs to be decelerated. Similarly, if the grate speed is relatively small, it needs to be accelerated. The feeder and grate are controlled in series, so it is necessary for relevant staff to input the required steam flow value, apply the function to convert the steam flow value into the grate speed value, and then give the speed. It is also necessary to compare the feeder grate speed with the converted grate speed. In the actual speed control, the concept of deviation value of steam flow process value PV steam flow set value SV is introduced. If the deviation value is higher than the set value, the combustion value of waste incineration will be high, so it is necessary to manually intervene the combustion control before the deviation value becomes larger

3. Air volume control

the air volume control of the grate combustion system in waste incineration is mainly completed by adjusting and controlling the opening of the forced air supply damper. It is necessary to maintain the static pressure in the bellows at about 4.0kpa. The German Martin grate has four forced air supply dampers, and the No. 2 damper is the main damper. On the touch screen, there will be 1#, 3#, 4# damper and 2# damper to form an opening deviation, which can be displayed in the DCS operation display screen. In the non series control mode, the opening value of the main damper is the opening value of the forced air supply damper in the DCS system, and the opening deviation of the other three dampers is formed on the basis of this opening value. In the series mode, the opening value of the main baffle is obtained by the function calculation of the set value of the main steam flow, and the corresponding air volume value is designed according to the expected main steam flow

conclusion: To sum up, through the effective application of German Martin row electric incineration equipment in waste incinerators, we can well realize the pollution-free and resource-based treatment of waste, and can also use the heat energy generated by waste incineration to generate electricity, which greatly improves the treatment effect of waste incineration, responds to the call of the 18th CPC National Congress for the construction of ecological civilization, and improves the burnout rate of waste incineration, At the same time, it also reduces the air pollution from waste incineration