A kind of sludge fuel stick and preparation method thereof
Technical field
The invention belongs to solid waste disposal and dispose, particularly relate to the method for sewage treatment plant residual recycling sludge.
Background technology
Along with the raising year by year of Chinese city sewage total amount and processing rate, the output of municipal sludge has also taken place significantly to increase.By the end of the end of the year 2002,537 of the existing municipal sewage plants of China, processing power reaches 13,000,000,000 t/a, can produce dewatered sludge 1,300 ten thousand t/a.Plan according to municipal sewage treatment in China's national economy evolutionary operation(EVOP) and the water prevention and cure of pollution planning: by 2010, the municipal sludge quantity discharged will reach more than 1,200 ten thousand t/a (dry-matter), dewatered sludge is pressed water ratio 80% and is calculated, and can produce more than dehydration municipal sludge 6,000 ten thousand t/a.
Municipal sludge contains organic matter, heavy metal element such as nutritive element such as nitrogen, phosphorus, potassium and Ni, Pb, Cr, Cu, Zn.Organism rots easily without stabilization treatment, and nutritive element and heavy metal substance also can cause second environmental pollution.In the face of arduous sludge treatment handling problems, Chinese Government pays much attention to, formulated in succession " pollutent control criterion in the agricultural mud " (GB4284-84), " urban wastewater treatment firm pollutant emission standard " (GB18918-2002), " municipal sewage plant's sewage sludge emission standard " (CJ3025-93) and " municipal sewage treatment and pollution prevention technique policy ", the treatment and disposal of mud has been proposed strict requirement.
The sludge ultimate disposal method mainly contains throws extra large evacuation, agricultural use, landfill, compost, burning or alternate manner disposal and utilization.Account for 44.8% in that Chinese mud is agricultural, the land landfill accounts for 31%, and other disposal accounts for 10.5%, accounts for 13.7% without what dispose.Mud is agricultural longer at Chinese applicating history, but the loss of the heavy metal contamination that it causes, pathogenic agent, hardly degraded organic substance and nitrogen, phosphorus makes the standard of its application more and more stricter to surface water and phreatic pollution.Sanitary landfill is subjected to the restriction of land used, and development prospect is not good.Compost treatment is unfavorable for sustainable development to site area requirements big transportation and processing costs that also need be higher.Burning is one of method for sludge treatment the most completely, and it can make the whole carbonizations of organism, and pathogen kill can reduce sludge volume to greatest extent, is one of main development trend of handling in the world in mud.The consolidating to contain of mud contains a large amount of organic compositions (>60%) in the thing, burning can release of heat.The combustion heat value of dewatered sludge (water ratio is 0) is by conservative 4000 kcal/kg that are thought of as.Utilizing mud to make existing patent aspect the synthol abroad, with coal: mud: zeolite is made fuel pellet with 65: 25: 10 mixed, also can be according to coal: mud: zeolite: rice bran equals 45: 35: 10: 10 or coal: mud: zeolite: unslaked lime equals 40: 40: 10: 10 ratio synthol, wherein the ratio of coal near in addition surpass half, incendiary mainly is a coal in the propellant combination.Therefore cost is higher, be unfavorable for popularizing in an all-round way, if can further improve the calorific value of mud by certain pre-treatment, reduce the ignition dope addition in the propellant combination, make full use of the heat that produces in the burning process, reduce the cost of sludge treatment disposal even can obtain income, under present energy-intensive situation, will have great competitive power with energy form.
Summary of the invention
The objective of the invention is to propose a kind of technology of utilizing mud to produce fuel stick according to the problem that the sludge disposal present situation exists.
A kind of sludge fuel stick that the present invention proposes, it is characterized in that: described fuel stick contains dewatered sludge, ignition dope, binding agent, sweetening agent, and its mass percent is: dewatered sludge 50~70%, ignition dope 20~50%, binding agent 3~5%, sweetening agent 5~10%.
In above-mentioned sludge fuel stick, described ignition dope is any in flyash, straw, cereal or the coal.
In above-mentioned sludge fuel stick, described binding agent is any in glass cement, clay or the cement.
In above-mentioned sludge fuel stick, described sweetening agent is Ca (OH)
2Any in/CaO, slag, cinder or the flying dust.
The preparation method of a kind of sludge fuel stick that the present invention proposes, it is characterized in that: described preparation method is:
(1) will pack in the stirrer through the mud after the dehydration, and add ignition dope, binding agent, sweetening agent in proportion, and stir, described interpolation mass percent is an ignition dope 20~50%, binding agent 3~5%, sweetening agent 5~10%;
(2) said mixture is packed into tablets press, granulating and forming makes sludge fuel stick after the oven dry.
Characteristics of the present invention are with mud to be main component, and the ratio of ignition dope is lower than 30%, only play the effect of regulating fixed carbon, improving combustion conditions, and heat is then mainly provided by mud.And with straw, cereal etc. as ignition dope, can fuel saving the cost of rod, solved the problem of outlet of these agricultural wastes again.And binding agent also can adopt clay material so cheaply except adopting conventional glass cement, and this exterior-applied liquid medicine mud can play the effect of stabilizing heavy metal as binding agent.And sweetening agent is except adopting commercial Ca (OH)
2Outside/the CaO, also can adopt the flying dust of slag, cinder even low-heavy metal content, heavy metal composition wherein can carry out stabilization by binding agents such as cement and solidify.Therefore, one aspect of the present invention is disposed sludge stabilizing effectively by burning, also realized the disposal of solid waste such as straw, slag, cinder and flying dust, reached function of processing waste with waste, utilized the heat of mud on the other hand, and reduced the cost of additive, realized the doulbe-sides' victory of social benefit and economic interests.
Description of drawings
Fig. 1 is the technological process of production of sludge fuel stick of the present invention.
1---ignition dope, 2---binding agent, 3---sulphur-fixing agent, 4---pulverizer, 5---mixing device, 6---tablets press, 7---fuel stick.
Embodiment
Below in conjunction with embodiment technical scheme of the present invention is described further:
To pack in the stirrer through the mud after the dehydration, add category-A material, category-B material and C class material according to a certain percentage, stir.With the mixture tablets press of packing into, red-tape operati condition granulating and forming can make sludge fuel stick after the oven dry.Sludge fuel stick is through Experiment of Thermophysics and pollutent measure of control, and the thermal technology that its performance reaches combustion power generation requires and the pollutant emission requirement, promptly can be used as finished product and is used for combustion power generation.
Its concrete technological step is:
A. ignition dope;
Table 1 ignition
dope kind
| 1 | 2 | 3 | 4 |
Title | Flyash | Straw | Cereal | Coal |
B. binding agent;
Table 2 binding agent kind
Numbering | 1 | 2 | 3 |
Title | Glass cement | Clay | Cement |
C. sweetening agent;
Table 3 sweetening
agent kind
| 1 | 2 | 3 | 4 |
Title | Ca(OH)
2/CaO
| Slag | Cinder | Flying dust |
To pack in the stirrer through the mud after the dehydration, and add category-A material, category-B material and C class material according to a certain percentage, and stir, proportioning sees Table 4.With the mixture tablets press of packing into, red-tape operati condition granulating and forming can make sludge fuel stick after the oven dry.Sludge fuel stick is through Experiment of Thermophysics and pollutent measure of control, and the thermal technology that its performance reaches combustion power generation requires and the pollutant emission requirement, promptly can be used as finished product and is used for combustion power generation.
Each set of dispense ratio of table 4
Component | A | B | C | Dewatered sludge |
Ratio (%) | 20~50 | 3~5 | 5~10 | 50~70 |
According to experimental result, the sludge fuel stick that the scheme of being mentioned in the invention is made, its combustionproperty is good, and the pollutent of discharging also meets the requirements.
Embodiment 1
The municipal sewage plant, Qinhuangdao adopts Wastewater Treated by Activated Sludge Process, and the character of its dewatered sludge is as follows:
Water ratio (%) | Volatile content (%) | Ash oontent (%) | Fixed carbon (%) | Lower heat value (kcal/g) |
84.20 | 40.95 | 56.66 | 2.39 | 457 |
Produce fuel stick with this dewatered sludge, its component and proportioning such as following table:
Component | Mud | Coal | Glass cement | Unslaked lime |
Proportioning (%) | 70 | 20 | 5 | 5 |
The character of fuel stick is as follows:
Water ratio (%) | Volatile content (%) | Ash oontent (%) | Fixed carbon (%) | Lower heat value (kcal/g) |
40.90 | 31.73 | 42.31 | 25.96 | 2735 |
Its thermal property is as follows:
Point of ignition (℃) | Flue-gas temperature (℃) | Unburned combustible in slag (%) | Thermo-efficiency (%) |
397 | 147 | 8.77 | 78.94 |
This industrial experimentation scale is the sewage load of 30000T/D, and the dewatered sludge that produce every day can make fuel stick 24T.
As generating, efficiency of combustion and efficiency of generator be respectively in 50% and 30% after the fuel stick combustion heating, but then every day altogether generated energy be:
4.8 * 10
7Kcal * 4.2kJ/kcal * 50% * 30%=3.0 * 10
7The kJ=8400 degree
About 336 degree of whole dehydration and fuel stick production process consumes power every day.
Then the clean electric weight that produces every day is:
The 8400-336=8064 degree
According to the present renewable energy power generation electrovalence policy that is incorporated into the power networks, every degree electricity is by 0.50 yuan, and the economic benefit that then annual generating produces is:
* 365 days * 0.5=1471680 of 8064 degree unit
The coal of using every day is 10 tons, and then 1 year is 3650 tons with coal, and the unit price of coal is in 300 yuan, and the cost of then buying coal is: 1095000 yuan.
Therefore annual net income is 376680 yuan.
Embodiment 2
Municipal sewage plant, Nanshan District, Shenzhen adopts oxidation ditch process to dispose of sewage, and the character of dewatered sludge is as follows:
Water ratio (%) | Volatile content (%) | Ash oontent (%) | Fixed carbon (%) | Lower heat value (kcal/g) |
82.70 | 42.32 | 55.64 | 2.04 | 463 |
Produce fuel stick with this dewatered sludge, its component and proportioning such as following table:
Component | Mud | Straw | Cement | Flying dust |
Proportioning (%) | 50 | 40 | 5 | 5 |
The character of fuel stick is as follows:
Water ratio (%) | Volatile content (%) | Ash oontent (%) | Fixed carbon (%) | Lower heat value (kcal/g) |
38.67 | 29.97 | 45.30 | 24.53 | 2904 |
Its thermal property is as follows:
Point of ignition (℃) | Flue-gas temperature (℃) | Unburned combustible in slag (%) | Thermo-efficiency (%) |
368 | 153 | 7.32 | 80.02 |
This industrial experimentation scale is the sewage load of 50000T/D, and the dewatered sludge that produce every day can make fuel stick 40T.
As generating, efficiency of combustion and efficiency of generator be respectively in 50% and 30% after the fuel stick combustion heating, but then every day altogether generated energy be:
9.0 * 107kcal * 4.2kJ/kcal * 50% * 30%=5.0 * 107kJ=14000 degree
About 600 degree of whole dehydration and fuel stick production process consumes power every day.
Then the clean electric weight that produces every day is:
The 14000-600=13400 degree
According to the present renewable energy power generation electrovalence policy that is incorporated into the power networks, every degree electricity is by 0.50 yuan, and the economic benefit that then annual generating produces is:
* 365 days * 0.5=2445500 of 13400 degree unit
The coal of using every day is 15 tons, and then 1 year is 5475 tons with coal, and the unit price of coal is in 300 yuan, and the cost of then buying coal is: 1642500 yuan.
Therefore annual net income is 803000 yuan.