System and method for pretreatment of high ammonia nitrogen acid condensate in conversion unit

Abstract

The invention belongs to the field of coal chemical wastewater and waste gas treatment, and in particular relates to a pretreatment system and method for high ammonia nitrogen acidic condensate of a conversion unit. The present invention replaces the circulating water heat exchanger of the coal gasification conversion unit with a desalinated water heat exchanger, uses the desalted water as the heat medium to recover heat, reduces the load of the circulating water field, and raises the temperature of the stripping liquid at the entrance of the separation tower to 100°C to 138°C. ℃, the acidic condensate (containing high ammonia nitrogen) sewage waste water is pretreated in the separation tower using a similar steam stripping method, so that the dissolved gases (high ammonia nitrogen substances, etc.) in the liquid phase are vaporized and separated as much as possible. The results show that: the total amount of high-ammonia-nitrogen substances, organic matter and sulfur-containing compounds in the gas phase increases significantly, while the liquid phase finally enters the biochemical unit with a low total amount of less than 50kg / h, which reaches the processing load of the biochemical unit, thus ensuring economical efficiency. Up-to-standard discharge after biochemical treatment.

Description

Technical field: [0001] The invention belongs to the field of coal chemical wastewater and waste gas treatment, and in particular relates to a pretreatment system and method for high ammonia nitrogen acidic condensate of a conversion unit. [0002] technical background: [0003] Ammonia nitrogen wastewater has great harm to the natural environment and human body. The main hazards of ammonia nitrogen pollution are: disturbing the normal balance of dissolved oxygen in the water body and further deteriorating the water quality; affecting the water quality of the water source and increasing the burden of water treatment; accelerating the eutrophication process of the water body. [0004] The treatment of high ammonia nitrogen wastewater is an urgent problem for enterprises to solve. According to the concentration difference, ammonia nitrogen wastewater is divided into 3 categories: (1) High concentration ammonia nitrogen wastewater: NH 3 -N>500mg / L; (2) Medium concentration ...

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Problems solved by technology

[0008] The patent (ZL 200910098944.6) discloses a stripping method of process condensate in CO conversion. In order to solve the problem of ammonium salt crystallization blockage in the conversion process condensate stripping system, two stripping towers are used to separate CO 2 and NH 3 stripping, avoiding CO 2 and NH 3 The possibility of simultaneous existence in the system prolongs the period of stable operation of the conversion device, but it does not fundamentally solve the problems of pipeline and equipment blockage and corrosion

[0009] However, the solutions of the above patents all solve the problem by adding a stripping tower. The two-tower process not only increases the complexity and uncontrollability of the process, but also greatly increases the cost and occupies the site.

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