Energy-saving environment-friendly integrated recycling and utilization method of coal chemical gasification washing black water high-temperature flashing steam

Abstract

The invention relates to an energy-saving environment-friendly integrated recycling and utilization method of coal chemical gasification washing black water high-temperature flashing steam. According to the energy-saving environment-friendly integrated recycling and utilization method, gasification washing black water is subjected to vacuum flashing so as to obtain high-temperature flashing steam with a temperature ranging from 170 to 179 DEG C, the high-temperature flashing steam is delivered into a second stage dehydration tank for dehydration, and then is delivered into a washing tower for full washing and dehydration; the high-temperature flashing steam is delivered into a grey water heat exchanger to heat grey water, and then is delivered into a stripping tower reboiler to heat column reactor steam stripping qualified liquid; un-condensed high-temperature flashing steam is delivered into a stripping tower for ingredient separation and recycling; and high-temperature flashing steam obtained from a first stage fractional condenser and a second stage fractional condenser is delivered into the stripping tower for steam stripping, separating, and recycling; and at last, scaling ingredients in the high-temperature flashing steam are moved completely, full utilization of the high-temperature flashing steam is realized, grey water is diluted, so that scaling caused by recrystallization is not caused, and complete recycling of grey water is realized.

Description

technical field [0001] The invention belongs to the waste gas and wastewater treatment links in the fields of coal chemical industry, new energy chemical industry, petrochemical industry, etc., and specifically relates to the treatment of water vapor, ammonia gas, hydrogen sulfide, carbon dioxide, carbon monoxide and other components produced by high-temperature flash evaporation of gasification washing black water In high-temperature flash gas (abbreviated as high flash gas, the same below), the separate utilization and step-by-step separation methods of water vapor, ammonia, hydrogen sulfide, carbon dioxide, and carbon monoxide, and the comprehensive utilization method of high flash gas. Background technique [0002] Coal chemical, methanol, ether, dimethyl ether and other chemical and emerging energy companies form high-temperature gasification washing water at 220-280 ° C during the cooling and washing process of coal gasification and gasification gas, which is called gas...

AI Technical Summary

Problems solved by technology

Due to the existence of liquid water, some inorganic salts will be dissolved in it. When using the heat of high flash gas, the water vapor in it will condense and drop in temperature, and the heat released will first evaporate the liquid water in high flash gas, and then make Inorganic salts in liquid water precipitate and crystallize at the pipes and valves on the shell side of the heat exchanger, and the calcium silicate, calcium carbonate, and magnesium carbonate in them will form scaling; due to the existence and content fluctuation of non-condensable gas in high flash gas, making The water vapor in it is heated unevenly during condensation, so that even if water vapor condenses, it is difficult to completely dissolve and wash away the scaling on the tube wall, so that the heat exchange effect of the heat exchanger is affected. This is especially the case with shell and tube heat exchangers; due to the poor heat transfer effect, the condensation effect decreases, and the amount of water vapor in the high flash gas condenses less and less, while the liquid water in it will still evaporate, which will lead to fouling It is getting heavier and heavier, which will seriously affect the heat exchange efficiency; because the high flash gas cannot be fully condensed, it is difficult to make full use of its heat energy. Many manufacturers have no choice but to directly vent it, which not only loses heat energy, but also seriously pollutes the environment. Also waste ammonia, sulfur, carbon dioxide and other resources

On the other hand, when enterprises use high flash gas to heat gray water, since the above-mentioned calcium carbonate, magnesium carbonate, calcium silicate, aluminum silicate and other inorganic salts in the gray water are almost in a saturated state, when the temperature rises, it is very easy to be absorbed in the heat exchange tube. The wall crystallizes and precipitates, forming scale, and more and more, even blocking the heat exchange tube; and due to the existence of calcium silicate, the scale formed is difficult to dissolve with general strong acid and strong alkali, and it is very difficult to remove, making the enterprise The heat exchanger has to be replaced frequently, which seriously affects the normal operation and economic benefits of the production system

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