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Generation and harm of a gas furnace, phenol water
1, phenol, cyanide wastewater
Phenol containing sewage gas station by phenol, cyanide, tar, suspended solids, sulfide, ammonia and other harmful substances. The phenolic to phenol, phenol content was the highest, followed by between p-cresol, phenol water mainly from indirect cooler gas purification process of condensed water and water water, the phenol containing condensed water generated depends on the amount of coal gasification and the gasification process. As a unit of two section gas station of Datong coal gasification as an example, the upper end gas by indirect cooler cooling, condensation water generated about 100kg/t coal, the condensed water containing phenol was about 8500-10000mg/l; gas washing water under the phenol content of 10mg/l, such as the use of water cooling method, with the increase of water circulation the use of time, the phenol content also increased, increased to a certain extent, it will affect the mass transfer of washing and cooling equipment in the heat exchanger, which brought a series of adverse effects.
Harm 2, phenol, cyanide wastewater
Phenol is referred to as phenol, also known as carbolic acid, acidic (corrosive), can be volatile at room temperature, the release of a special kind of irritating odor in the air, pink. The "water" disinfectant hospital is the dilute solution of phenol sodium salt. Cresol also called similar chemical activity and cresol, phenol toxicity, also often exist at the same time.
According to the phenolic hydroxyl groups on the aromatic ring of the direct connection of the different, can be divided into phenols and polyphenols; according to the volatile and can be divided into volatile phenol and volatile phenol. A more volatile phenol (in the boiling point of 230 DEG C). The phenol compound is a prototype poison, to life all individuals are toxic. Make the protein coagulation, so there is a strong bactericidal effect. The solution is easy to cause systemic poisoning through skin; the steam by inhalation, greater damage to the nervous system. Long term inhalation of vapor or generation of phenol concentration phenol contaminated water can cause chronic accumulation of poisoning; inhalation of high concentration of phenol or phenol solution or a phenol vapor liquid splashing into the skin can cause acute poisoning. If not timely rescue, can be in three to eight hours because of nerve paralysis and. A chronic phenol poisoning vomiting, diarrhea, loss of appetite, dizziness, anemia and nervous system disorders. The crops have certain toxicity to aquatic microorganisms, no phenol and. The water containing phenol 0.1 ~ 0.2 mg / L, that is to eat fish odor; 6.5 ~ 9.3 mg / L, can damage the gills and pharynx, the abdominal hemorrhage, even death. Phenol concentration higher than 100 mg / L of wastewater directly for irrigation, crops and production will cause. The phenol oral lethal dose of 530 mg / kg body weight.
Most inorganic cyanide is highly toxic, highly toxic substances, a very small amount of cyanide (milligram per kilogram of body weight will make people, and in a very short period of time with cyanide poisoning, a very low concentration of water (<0.05mg/L) will make the fish and other aquatic organisms can cause poisoning, crop production. Cyanide pollution caused by livestock and fish populations, acute poisoning cases were reported, both at home and abroad. These events are due to the short term will be discharged into the water caused by the large number of cyanide. Therefore, in the process of industrial production, and must be used to strictly control the emissions of cyanide. Especially to improve the sewage treatment facilities to reduce the discharge of cyanide.
3, to the interests of illegal enterprises, wind and waste
Illegal cost is too low, is an important reason for many enterprises illegal sewage. Under the condition of market economy, to maximize the pursuit of economic interests, is the main purpose of the business activities of enterprises. Driven by interests, individual enterprises ignore national laws, illegal sewage, in order to reduce production costs, get more benefits, which is not surprising. A few illegal illegal sewage, resulting in a decline in environmental quality, some local ecological deterioration, not only endanger the health and normal production of the local people, and even become a factor affecting social stability.
4, the government, the overhaul of wastewater discharge enterprises, eliminate industrial wastewater pollution
Since June 1, 2008, the new "people's Republic of China began to implement the" water pollution prevention law. There are strict regulations and measures to deal with the illegal discharge of industrial wastewater. The State Environmental Protection Administration and other six ministries have begun to illegal sewage enterprises thorough investigation of environmental protection act, proposed to prosecute actions as rectifying and standardizing the market economic order, the organic part of Combating Unfair Competition, and strive to achieve a breakthrough in creating a fair competitive environment; at the same time, the six ministries said to seriously deal with the local government and relevant departments. Administrative omission. We believe that, with the social from all walks of life and people more awareness of environmental protection and waste, enterprises will inevitably can't do anything.
Two, gas furnace phenol water treatment status
For decades, how thorough treatment of phenol containing wastewater has been the environmental protection problem of gas station, engaged in the research of gas design industry experts after long-term research and discussion, although tried to find out some effective treatment methods, and achieved certain results, but there are still many shortcomings. The phenol water treatment process is starting from the source to treatment of wastewater containing phenol, phenol wastewater containing reasonable utilization, and achieved remarkable economic and environmental benefits.
1, the gas station of several conventional treatment methods of wastewater containing phenol
For the gas station of phenol containing wastewater treatment is generally divided into two stages:
The first stage: the preprocessing stage
The stage to the sewage to remove most of the suspended solids and tar;
The second stage: dephenolizing processing stage
The purpose is the pretreatment of wastewater in most phenols and organic matter removal.
The first stage: A) pretreatment method
The pretreatment method has been used in the gas station, about the following: natural sedimentation separation, mechanical filtration, chemical coagulation, electrolysis flotation, centrifugal separation, acid demulsification tar slag adsorption method, pressurized dissolved air flotation, gas float, negative pressure dephenolizing method.
The natural sedimentation method, can be directly arranged in the circulating water system of gas station in the process, although the effect is not very ideal, but the cost is relatively low, has been most gas stations as the pretreatment method of wastewater containing phenol. The other seven methods must be processed in separately disposed equipment, the relative cost is much higher.
B). The second stage: dephenolizing processing method
Dephenolizing processing method, which is the key link of phenol water treatment. Dephenolizing processing methods usually have steam chemical removal of phenol, phenol removal method, steam burning method, solvent extraction method, phenol sulfonated coal adsorption, sulphonated coal adsorption method, biochemical method, modulation of coal water slurry and coal fired boiler governance governance method of phenol containing wastewater.
2, analysis of various treatment methods and problems:
(1), steam chemical phenol removal method
With high temperature steam heating strong sewage containing phenol, the phenol in waste water evaporation with the steam to escape, and then pass into the alkali absorption into phenol sodium salt, so as to achieve the purpose of removing phenol. This method has the advantages of simple operation, less investment, but the steam consumption is larger, and the phenol removal efficiency is not ideal, is generally not up to the purpose of thoroughly governance. A factory has used the method of sewage treatment in phenol, after the steam consumption is too big to stop; a factory in Zhejiang had also adopted the method of phenol removal, the results will be eliminated.
(2) steam, phenol removal method
The phenol containing wastewater with steam heating, the phenol volatile out, then this part of phenol steam into furnace bottom mixed use air as gasification agent, phenol in the furnace at high temperature combustion is decomposed into CO2 and H2O to reach the purpose of removing phenol. The disadvantage is that this method can remove the low boiling point of phenols, and large energy consumption, evaporation per 1 tons of sewage is about 180 kilograms of standard coal equivalent fuel. A factory in Inner Mongolia had used treated sewage containing phenol, because of high energy consumption and gas furnace bottom saturation temperature is not easy to control and disabled.
(3), burning method
The phenol wastewater is sprayed into the incinerator, the phenolic compounds in high temperature of 1100 degrees Celsius, oxidation reaction, generating CO2 and H2O emissions, the method is simple, easy to operate, but high energy consumption, each burning 1 tons of wastewater containing phenol and its cost of about 1200-1500 yuan. 90 in the early two section gas imported and domestic supporting furnace basically are equipped with phenol water incineration facilities, but basically because of energy consumption and idle. The incineration treatment of wastewater containing phenol with another key disadvantage is that once the temperature drops, careless operation, often caused by incomplete combustion, easy to form two pollution. A Henan gas station daily phenol water about 4 tons, the incineration furnace phenol water treatment, the average 800m3 per hour to burn gas, burning phenol water about 170kg/h, according to this calculation alone each year burned about 1900000 yuan! At the same time also caused a large number of emissions.
(4), solvent extraction dephenolization method
The main process of the method is divided into two parts: extraction and desorption, the extraction process is a process of redistribution of material, the use of phenol extractant extracted from wastewater containing phenol; extraction agent then contact with lye, phenol and alkali extraction agent in the reaction of phenol sodium salt, the process is a process of desorption. By using the method of phenol treated effluent is 100-200mg/l containing phenol, can not be discharged directly, and the extractant can cause loss of wastewater emulsification, and formed two pollution. In addition the method should be used in high efficiency extraction agent and alkali, high operation cost.
5), phenol resin method
The main process of the process including adsorption and desorption, adsorption of phenol in wastewater by resin, and then desorption was carried out with alkali solution, the process of generating phenol sodium, more complex, and there are many factors influencing the phenol removal efficiency, operation cost is relatively high.
6), sulfonated coal adsorption method
The sulfonated coal polar groups adsorption phenol, followed by alkali absorption and sodium phenol phenol, sulphonated coal adsorption is intermittent, complete a cycle including adsorption and regeneration of two links. The main drawback of this method is low phenol content sulphonated coal adsorption, adsorption cycle is too short, analytical, regeneration is also difficult. A factory in Northeast has been used for treating phenolic wastewater by this method, the adsorption rate decreased too quickly and give up.
(7), biochemical method phenol resin method
Biochemical treatment of phenol wastewater is the cultivation of microorganisms, and by microorganisms of phenolic compounds in wastewater digestion absorption into H2O and CO2. According to the bearing mode and way of oxygen supply can be divided into different aeration process, contact oxidation, biological rotary method and biological filter and other microorganisms. The biochemical method on the water quality of sewage into the pool of biochemical requirements more stringent, tar and phenol and other organic matter concentration in sewage can not exceed the concentration of microorganisms, can withstand otherwise, need to be diluted to enter the sewage biochemical tank, thus limiting water treatment. At the same time, microbial acclimation is difficult, the influent concentration exceed the standard, environment temperature, are easy to limit microbial survival. A biochemical method used in sewage treatment plant northeast of phenol, due to strict conditions to make the processing cost is very high.
(8), "coal phenol water" modulation of coal water slurry treatment of wastewater containing phenol principle
The development of the technology of coal water slurry in China began in twentieth Century 80, after 20 years of practice, has become a relatively mature technology, system. Coal water slurry is pulverized coal (60-70%), water (30-40%) and additives (about 1%) after mixing, grinding, stirring, slurry flow to the formation of coal - water phase to use as fuel. Like the appearance of oil coal water slurry, good liquidity, is a new generation of low pollution, fuel oil, its calorific value is about half of the heavy oil, has been successfully applied in metallurgy, building materials and other industries of various industrial furnaces and boilers, has good prospects for development. According to the application of coal water slurry technology, using gas station's sieve coal and sewage mixed according to a certain proportion of phenol, adding proper amount of additives for coal water slurry by the strong grinding modulation, then phenol containing wastewater has become an effective carrier of fuel coal. The combustion temperature of coal water slurry is 1100-1300 DEG C, this temperature phenol in waste water and other harmful organic substances burns rapidly decomposed into H2O and CO2, and then with the combustion flue gas discharged into the atmosphere, so as to achieve the purpose of treatment of wastewater containing phenol, the phenol removal mechanism and burning method the same.
Although you can use phenol containing wastewater to prepare coal water slurry, but because of the general gas station, phenol water coal proportion difficult to balance, and the gas station, coal water slurry production, in addition to increase the number of equipment, the product also has a lot of problems. Because of the general gas station coal consumption is small, still need to be equipped with special vehicles, the quality of coal water slurry can not be guaranteed.
At present, there are many areas of Guangdong Foshan building ceramics factory will be commissioned by the phenol water treatment of coal water slurry processing factory.
A building materials factory we visited Foshan Baini town as an example: the factory is 3.2 meters two stage gasifier two, the phenol water production capacity of 12 tons, Japan produced phenol water stored in the 3.5 meter deep phenol pool, two or three days interval produced by manufacturers and application of coal water slurry. Pay for water coal slurry production costs 100 yuan / ton, daily processing costs 1200 yuan.
In phenol water treatment cost: 1200 x 365=438000 yuan =43.8 yuan
The power plant equipment department hejingli told us: in the coal water slurry manufacturers under the condition of normal use of phenol water, the phenol water to the normal day off, but encountered at the end and the beginning of the coal water slurry, manufacturers will not be discontinued, phenol water treatment, only digging pool storage, a huge burden to the enterprise the development of enterprises, problems.
(9), coal-fired boiler treatment of wastewater containing phenol
This method is relatively simple, the phenol containing wastewater and boiler coal-fired boiler to stir, add. The use of high temperature combustion in the boiler, the phenol containing wastewater is decomposed into CO2 and H2O together with the flue gas is discharged, the method is the most simple, most energy-saving. But because of volatile phenol containing wastewater containing phenol, cyanide in high concentration of boiler operators and serious environmental pollution. And the small boiler general unstable boiler load, when the load is low, the low temperature is not up to the decomposition temperature of phenol, with the flue gas will be released into the atmosphere, cause two pollution, pollution area is more difficult to deal with.
Analysis of the factors restricting the gas station 3, conventional treatment methods of phenol containing wastewater application:
According to the analysis, several of the above routine administration of gas station of wastewater containing phenol method can be seen, and influence factors of gas station wastewater containing phenol with conventional treatment methods applied mainly in the following points:
1 in addition to steam phenol method and burning method, the remaining several treatment methods of sewage pretreatment requirements are very strict, but the process is relatively complex, a large investment, for some small and medium sized gas station is difficult to bear.
2 by their own dephenolizing process and effect of phenol removal efficiency requirements, operation cost of sewage containing phenol method is better than conventional treatment.
3 in addition to burning method, other methods are aimed to remove phenol in wastewater, but the phenol removal after the water also is not clean water, because even after processing the water phenol content reached the emission standard, the water can not discharge, but also as the water content of the other organic compound, inorganic salts such as whether to meet emission standards and.
4 phenol removal efficiency is not high, management is not complete, easy to form two pollution, which is restricted to some other key application methods of phenol removal.
Two, the gas furnace containing phenol, cyanide wastewater treatment system feasibility
1 working principle
The need to increase the amount of gas generating furnace gasification steam gasification with air, the air becomes saturated at the temperature of the furnace, supply as the principle of gasification agent. The water jacket furnace produces water vapor by indirect heating by gas, in phenol water evaporation box, the phenol containing wastewater is heated to a suitable temperature, pressed by pump atomization and enter the gas furnace air quality and heat exchange to achieve gas furnace for gasifying agent for saturation temperature. Sent to the gas stove bottom as gasifying agent. In the event of fire layer 1100 - 1200 Deg. C, phenol and other harmful substances will be decomposed into CO and H under reducing conditions2.
The required amount of 260kg/t vaporization steam coal gasifier, the gas condensate water as gasifying agent added completely using the gas station can reach the sewage, and the phenol, cyanide and other pollutants in the waste heat recovery, improve the calorific value of gas.
In the area of large diurnal temperature using the device and the existing gasification agent adding device has obvious advantages, because the temperature of gasification gas furnace is an important factor in determining the quality of the gas, generally does not occur in the fuel gasifying agent temperature control requirements in the 1 + C ensuring gas quality does not change, when the temperature change over 1 + C, the quality of the gas will change greatly. Therefore, often need to be adjusted according to the test results, to ensure the quality of gas. This device is to control the temperature of gasification agent by controlling the water temperature in the water tank to maintain a constant phenol. Because the heat capacity of water is 4-5 times of the air, therefore, regardless of the temperature difference between day and night or seasonal temperature difference will not affect the temperature of gasification agent, reduce labor intensity, improve the stability of gas quality, and reduce the losses caused by improper operation. According to the calculation of equipment of phenol water treatment capacity of 24 tons / day.
The device uses the gas furnace gasification need to increase the amount of water vapor, the gasification with air becomes saturated air at the temperature of the furnace, supply as gasifying furnace principle, water gas produced by water vapor, water evaporation in phenol phenol containing wastewater in the box will be heated, pressed by pump atomization and air mass and heat exchange gas furnace to reach the saturation temperature of the gasification agent requirements.
In the south, because the summer high temperature, high humidity, small temperature difference between day and night, the relative amount of phenol water treatment equipment to the north. According to the calculation of the highest, Guangdong area temperature and humidity, maximum temperature difference between day and night minimum weather conditions (7, 8, September), our equipment processing phenol water capacity of 14 tons / day, still be able to meet the current phenol water treatment gas station. In October -6 months during the treatment of phenol water equipment average capacity of 20 tons / day.
Analysis and calculation are as follows:
According to the Guangzhou July day and night average temperature of 30 degrees Celsius, the air humidity is 80%.
According to the heating and ventilation design handbook of moist air parameters in the air pressure is 100kPa, saturation moisture content is 27.329g/kg, calculate 21.86g/kg according to Guangzhou air humidity 80%, converted to 30 DEG C air density is 1.165kg/m3Each, M3The air humidity is 25.47 g/m3Assuming the gasifier gasification temperature is 50 DEG C, the air volume is 0.9154 M3/kg, the air density is 1.092 g/m3Per cubic meter of water vapor saturated air 94.76g/m3Each deducted from the original 30 DEG air with water, gas furnace gasification to add water (steam) was 94.76-25.47=69.29 g/m3About 2.8 m gasification gas furnace every 1kg coal gasification3Therefore, gas, gasification of water (steam) for 69.29x2.8=194.012 coal g/kg.
According to the calculation of 3.5t coal gasification per hour:
Treatment of phenol water per hour: 194.012x3500=679042g = 679kg
Daily processing: 679kgx24=16296kg is about 16 tons of phenol water,
That is to say, in the hot and humid summer, our equipment processing capacity could reach 16 tons / day.
2 technical characteristics:
1). The phenol water vapor as gasifying agent used, completely solve the problem of phenol water discharge two section type gas furnace;
2). Phenol containing wastewater treatment with low cost. No other daily operation cost only less than 18kW power consumption abroad;
3). Phenol and other organic matter pyrolysis product is H2Then, CO is full, can effectively improve the calorific value of gas 20-200kJ/m3;
4). Phenol containing wastewater in the box for negative pressure evaporation, phenol water and cyanide will not leak caused by environmental pollution, beneficial to the health of workers to improve the environment;
5). The 1100-1200 high temperature treatment, the complete decomposition of phenol containing wastewater, no two pollution;
6). At the bottom of the saturated air temperature stability, temperature changes by small, easy to adjust;
7). Soft water recycling, water vapor yield, no scaling. And each hour to save 500 kilograms of water softening;
8). Outdoor equipment can be arranged with less investment, low maintenance cost;
9). Windproof, rainproof, dustproof design, environmental adaptability;
10). Furnace containing phenol, cyanide wastewater treatment device of low cost gas, does not affect the installation of production;
11). To reduce boiler steam quantity, save a lot of energy.
3 significant economic and social benefits, can achieve the transformation of production
In the two stage gasifier two, the phenol water production was 12 tons as an example. Using this technology, daily production of phenol water as gasifying agent used, processing cost per hour is only 18kW per kWh of electricity consumption, calculated 0.9 yuan, only 16.2 yuan!
Daily processing costs 16.2 yuan * 24=388.8
Annual treatment costs 388.8 * 365=14.2 million. Phenol water treatment cost is very low. |
