Waste to Enenrgy
Comprehensive overview
In the face of the world’s increasingly rapid urbanization, the proliferation of urban garbage has become a major urban disaster. Countries around the world have not only confined themselves to the passive “defensive” tactics of burying and destroying garbage, but have actively taken strong measures to comprehensively treat and utilize garbage in a scientific and reasonable manner. The abundant garbage resources have great potential benefits. The city’s annual loss due to garbage is about 30 billion yuan (transportation costs, treatment costs, etc.) and its comprehensive utilization can create 250 billion yuan of benefits.
Since the 1970s, some developed countries have begun to use the heat generated by the incineration of waste for power generation. According to the relevant statistics, today’s urban waste removal volume has reached 1 trillion t / a, if the average low calorific value of 2900kJ / kg, equivalent to 14 million tons of coal. If 1/4 of them are used for incineration power generation, the annual power generation can be up to 6 billion kwh, equivalent to the installation of 1200MW thermal power unit power generation. Harmless waste incineration power generation can realize the harmlessness of garbage, discretionary garbage incineration at high temperatures (about 1000 ℃), can be sterile and decomposition of hazardous substances, and the tail gas is purified and processed to meet the standards of emission, more thoroughly harmless. The residue after the incineration of reduced garbage, only 10% to 30% of the original volume, thus extending the life of the landfill, easing the land resource constraints. Therefore, the construction of waste-to-energy plants is very conducive to the city’s environmental protection, especially the protection of land and water resources, and the realization of sustainable development.
Simon Energy started to participate in major waste incineration power generation projects in China in 2018, and after years of digestion, absorption and re-innovation, we have accumulated considerable experience, and through the incinerator-boiler, flue gas purification system, leachate treatment system, and the corresponding control system, we are able to effectively process urban domestic waste with low calorific value and high water content in developing countries. Up to now, we have been able to provide the whole industry chain services of EPC contracting, complete set of equipment supply and operation management for waste-to-energy projects.
Grate incineration technology
1. The grate is characterized by a reverse-push reciprocating movement grate, consisting of a row of fixed grates and a row of movable grates installed alternately, the direction of movement of the grate is opposite to the direction of movement of the garbage, and the speed of movement can be adjusted arbitrarily, so as to adjust the residence time of the garbage in the grate according to the nature of the garbage and the combustion conditions. The grate is inclined at an angle of 24° in the furnace, and due to the role of tilting and pushing back, the garbage is constantly turned and stirred to realize full contact with the air, so that the garbage can be completely burned.
2. The ignition of the furnace is carried out by natural gas or light diesel oil, and is stopped after the ignition is completed. Start burning garbage without adding any auxiliary fuel, garbage continuous and stable combustion can ensure that the furnace outlet temperature control at 900℃ to 1020 ℃, the furnace combustion condition is very good.
3. Garbage in the incinerator after full combustion to form slag, volume and weight reduction of about 80%. Under each incinerator there are 2 hydraulic wet slag removers installed to cool the slag falling from the furnace, and then through the belt conveyor system, electromagnetic iron removal into the slag storage pit, resulting in a slag thermal scorching reduction rate of about 2%. The slag can be used as a building material for the manufacture of curbstones, sidewalk bricks, road base layers, etc.
Grate characteristics
- Reverse thrust tilt reciprocating motion
- Low maintenance costs
- Long grate life
- <3% Slag scorch reduction <3%
Flue gas purification technology
1. SNCR+semi-dry+dry+activated carbon+bag+SGH+low temperature SCR+GGH+wet+de-whitening flue gas treatment method is mainly adopted. The flue gas purification system mainly consists of spray tower, bag filter, lime slurry preparation system, activated carbon injection system, fly ash conveying system, flue gas emission system and flue gas online monitoring system.
2. Spray tower is cylindrical equipment. The flue gas enters the spray tower through the flue after the heat exchange is completed by the waste heat boiler. Before entering the spray tower, activated carbon is sprayed into the flue to effectively adsorb the heavy metals and residual dioxins in the flue gas by utilizing the great specific surface area of activated carbon. At the same time, the lime slurry is sprayed into the spray tower, the flue gas enters from the top of the spray tower, and turbulence is formed through the rotation of the deflector blade, when flowing, the lime slurry passes through the rotating atomizer with a speed of 5000 rpm to become lime slurry droplets, which are fully in contact with the flue gas and neutralize and absorb the acid gases, such as HCl, HF, SO2, etc. The flue gas coming out of the spray tower has already been absorbed. The flue gas coming out of the spray tower has been stripped of acidic substances, heavy metals and residual dioxins, and is introduced into the bag filter through the flue, where the dust is filtered through PTFE filter bags, further absorbing the acidic gases, and then sucked in by the induced draft fan to be discharged through the chimney.
EPC Participation Project Demonstration
Hunan Xiangxiang Waste Incineration EPC Project-2×300t/d
