Mixed fraction washing system for tar distillation

Abstract

The utility model belongs to the technical field of fraction washing, and particularly relates to a mixed fraction washing system for tar distillation, which comprises an unwashed naphthalene oil tank, an alkaline sodium phenolate elevated tank, a primary continuous washing separation tower and a washed naphthalene oil tank, and is characterized by also comprising a secondary continuous washing separation tower and a dilute alkali elevated tank, the output end of the unwashed naphthalene oil tank and the output end of the alkaline sodium phenolate head tank are respectively connected with the input end of the primary continuous washing separation tower, and the upper oil phase output end of the primary continuous washing separation tower is connected with the input end of the primary dephenolization buffer tank; the output end of the dilute alkali overhead tank and the output end of the primary dephenolization buffer tank are respectively connected with the input end of the secondary continuous washing separation tower, and the oil phase output end of the secondary continuous washing separation tower is connected with the input end of the washed naphthalene oil tank. According to the utility model, a secondary dephenolization process is adopted, and the secondary continuous washing separation tower is additionally arranged to carry out secondary dephenolization on the naphthalene oil, so that the purity of the finished product naphthalene oil is greatly improved.

Description

Technical Field

[0001] This utility model belongs to the field of fraction washing technology, specifically relating to a mixed fraction washing system for tar distillation. Background Technology

[0002] Naphthalene oil fractionation is one of the processes in coal tar fractionation. The naphthalene oil extracted from tar distillation contains many impurities, mainly phenolic impurities. Therefore, it is necessary to perform fractionation washing on the naphthalene oil to remove the impurities.

[0003] However, current naphthalene oil distillation processes generally involve a single phenol removal step, resulting in a high content of phenolic impurities in the finished naphthalene oil. As market demands for product purity increase, this process cannot meet market requirements. Furthermore, the high impurity content in the finished naphthalene oil also leads to a decrease in the yield of phenolic salt byproducts, impacting economic benefits. Utility Model Content

[0004] To address the problems existing in the prior art, this utility model provides a mixed fraction washing system for tar distillation, which employs a two-stage phenol removal process. By adding a secondary continuous washing and separation tower to perform secondary phenol removal on naphthalene oil, the purity of the finished naphthalene oil is greatly improved.

[0005] The specific technical solution adopted in this utility model is as follows:

[0006] A tar distillation mixed fraction washing system includes an unwashed naphthalene oil tank, an alkaline sodium phenolate high-level tank, a primary continuous washing separation tower, and a washed naphthalene oil tank. The system is characterized by further including a secondary continuous washing separation tower and a dilute alkali high-level tank. The output ends of the unwashed naphthalene oil tank and the alkaline sodium phenolate high-level tank are respectively connected to the input end of the primary continuous washing separation tower. The oil phase output end of the primary continuous washing separation tower located at the top is connected to the input end of a primary phenol removal buffer tank. The output ends of the dilute alkali high-level tank and the primary phenol removal buffer tank are respectively connected to the input end of the secondary continuous washing separation tower. The oil phase output end of the secondary continuous washing separation tower is connected to the input end of the washed naphthalene oil tank.

[0007] The aqueous phase output end at the bottom of the continuous washing separation tower is connected to the input end of the neutral sodium phenolate tank.

[0008] The output end of the neutral sodium phenolate tank is connected to the input end of the evaporation vessel via a sodium phenolate evaporation pump, and the liquid phase output end of the evaporation vessel is connected to the input end of the clean phenolate tank.

[0009] A heat exchanger is also provided between the output end of the sodium phenolate steam pump and the input end of the steam blowing vessel, and a cooler is also provided between the output end of the steam blowing vessel and the input end of the clean phenol salt tank.

[0010] The input end of the primary washing separation tower is equipped with a primary washing pump. The unwashed naphthalene oil in the unwashed naphthalene oil tank and the alkaline sodium phenolate in the alkaline sodium phenolate high-level tank are respectively extracted by the primary washing pump and mixed into the primary washing separation tower.

[0011] The secondary washing separation tower is equipped with a secondary washing pump at its input end. The primary phenol-removed naphthalene oil in the primary phenol-removed buffer tank and the dilute alkali in the dilute alkali high-position tank are respectively extracted by the secondary washing pump and mixed into the secondary washing separation tower.

[0012] The aqueous phase output end at the bottom of the secondary washing separation tower is connected to the input end of the alkaline phenol salt tank and the input end of the primary washing pump, respectively.

[0013] The beneficial effects of this utility model are:

[0014] 1. This utility model adopts a two-stage phenol removal process. By adding a two-stage continuous washing and separation tower to remove phenol from naphthalene oil, the purity of the finished naphthalene oil is greatly improved.

[0015] After undergoing a single phenol removal process in a continuous washing and separation tower, the naphthalene oil is mixed with dilute alkali. The remaining phenol in the naphthalene oil reacts with the dilute alkali to produce phenol salts and water. The mixture is then sent to a secondary continuous washing and separation tower for static separation. The washed naphthalene oil collected from the top of the tower has high purity.

[0016] 2. In this invention, the generated phenolic salts are purified to obtain high-purity phenolic salts, which can be sold or used as by-products, thereby improving the economic efficiency of the entire process. Attached Figure Description

[0017] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0019] A tar distillation mixed fraction washing system includes an unwashed naphthalene oil tank, an alkaline sodium phenolate high-level tank, a primary continuous washing separation tower, and a washed naphthalene oil tank. The system is characterized by further including a secondary continuous washing separation tower and a dilute alkali high-level tank. The output ends of the unwashed naphthalene oil tank and the alkaline sodium phenolate high-level tank are respectively connected to the input end of the primary continuous washing separation tower. The oil phase output end of the primary continuous washing separation tower located at the top is connected to the input end of a primary phenol removal buffer tank. The output ends of the dilute alkali high-level tank and the primary phenol removal buffer tank are respectively connected to the input end of the secondary continuous washing separation tower. The oil phase output end of the secondary continuous washing separation tower is connected to the input end of the washed naphthalene oil tank.

[0020] Current naphthalene oil distillation processes typically involve a single phenol removal step, resulting in a high level of phenolic impurities in the finished naphthalene oil. As market demands for product purity increase, this process fails to meet market requirements. Furthermore, the excessively high impurity content in the finished naphthalene oil also leads to a decrease in the yield of phenolic salt byproducts, impacting economic efficiency.

[0021] Therefore, this invention employs a two-stage phenol removal process. By adding a secondary continuous washing and separation tower to perform secondary phenol removal on naphthalene oil, the purity of the finished naphthalene oil is greatly improved.

[0022] Unwashed naphthalene oil from tar distillation enters the unwashed naphthalene oil tank and is extracted by a primary washing pump. Alkaline sodium phenolate from the high-level alkaline sodium phenolate tank is added to the extraction pipeline. Some of the phenol in the naphthalene oil reacts with the free alkali in the alkaline sodium phenolate to form sodium phenolate salt and water. This is then sent to the primary washing separation tower for static separation. The primary oil discharged from the top of the primary washing separation tower flows by gravity into the primary phenol removal buffer tank. The primary oil in the phenol removal buffer tank is extracted by a secondary washing pump, and a prepared 10-14% dilute alkali from the high-level dilute alkali tank is added to the extraction pipeline. The oil is thoroughly mixed by the secondary washing pump, and the remaining phenol in the naphthalene oil reacts with the dilute alkali to form phenolate salt and water. This is then sent to the secondary washing separation tower for static separation. The high-purity washed naphthalene oil collected from the top of the tower flows into the washed naphthalene oil tank as raw material for the industrial naphthalene distillation process.

[0023] The aqueous phase outlet at the bottom of the continuous washing separation tower is connected to the inlet of the neutral sodium phenolate tank. Sodium phenolate generated during the primary phenol removal process enters the neutral sodium phenolate tank through the bottom of the continuous washing separation tower.

[0024] The output end of the neutral sodium phenolate tank is connected to the input end of the evaporation vessel via a sodium phenolate evaporation pump, and the liquid phase output end of the evaporation vessel is connected to the input end of the clean phenolate tank.

[0025] A heat exchanger is also provided between the output end of the sodium phenolate steam pump and the input end of the steam blowing vessel, and a cooler is also provided between the output end of the steam blowing vessel and the input end of the clean phenol salt tank.

[0026] The neutral phenolic salt in the neutral phenolic salt tank is pumped into the phenolic salt heat exchanger by the sodium phenolate steam pump to raise its temperature, and then enters the steam blowing kettle. The steam blowing kettle is used to blow out the water and oil in the neutral phenolic salt. After being cooled by the cooler, it enters the clean phenolic salt tank for storage. The clean phenolic salt has high purity and can be sold or used as a by-product, thereby improving the economic efficiency of the entire process.

[0027] The input end of the primary washing separation tower is equipped with a primary washing pump. The unwashed naphthalene oil in the unwashed naphthalene oil tank and the alkaline sodium phenolate in the alkaline sodium phenolate high-level tank are respectively extracted by the primary washing pump and mixed into the primary washing separation tower.

[0028] The secondary washing separation tower is equipped with a secondary washing pump at its input end. The primary phenol-removed naphthalene oil in the primary phenol-removed buffer tank and the dilute alkali in the dilute alkali high-position tank are respectively extracted by the secondary washing pump and mixed into the secondary washing separation tower.

[0029] The unwashed naphthalene oil tank and the primary phenol removal buffer tank can be extracted by a primary and secondary continuous washing pump. During the extraction process, the naphthalene oil is fully mixed with the alkaline solution, which promotes the reaction between the phenol in the naphthalene oil and the free alkali, thereby improving the phenol removal effect of the naphthalene oil.

[0030] The aqueous phase output end at the bottom of the secondary washing separation tower is connected to the input end of the alkaline phenol salt tank and the input end of the primary washing pump, respectively. The alkaline phenol salt discharged from the bottom of the secondary washing separation tower has high purity and can not only be returned to the primary washing pump for phenol removal of naphthalene oil, but also be sold as a by-product.

Claims

1. A tar distillation mixed fraction washing system comprising an unwashed naphthalene oil tank, an alkaline sodium phenate head tank, a primary continuous washing separation column, and a washed naphthalene oil tank, characterized in that, The output end of the unwashed naphthalene oil tank and the output end of the basic sodium phenate high tank are respectively connected with the input end of the primary continuous washing separation tower, the oil phase output end above the primary continuous washing separation tower is connected with the input end of the primary dephenol buffer tank, the output end of the dilute alkali high tank and the output end of the primary dephenol buffer tank are respectively connected with the input end of the secondary continuous washing separation tower, and the oil phase output end of the secondary continuous washing separation tower is connected with the input end of the washed naphthalene oil tank.

2. A tar distillation mixed fraction scrubbing system according to claim 1, wherein, The water phase output end at the bottom of the primary continuous washing separation tower is connected with the input end of the neutral sodium phenate tank.

3. A tar distillation mixed fraction scrubbing system according to claim 2, wherein, The output end of the neutral sodium phenate tank is connected with the input end of the evaporation and blowing still through a sodium phenate evaporation and blowing pump, and the liquid phase output end of the evaporation and blowing still is connected with the input end of the pure phenate tank.

4. A tar distillation mixed fraction scrubbing system according to claim 3, wherein, A heat exchanger is further arranged between the output end of the sodium phenate evaporation and blowing pump and the input end of the evaporation and blowing still, and a cooler is further arranged between the output end of the evaporation and blowing still and the input end of the pure phenate tank.

5. A tar distillation mixed fraction scrubbing system according to claim 1 wherein, The input end of the primary continuous washing separation tower is provided with a primary continuous washing pump, and the unwashed naphthalene oil in the unwashed naphthalene oil tank and the basic sodium phenate in the basic sodium phenate high tank are respectively pumped out by the primary continuous washing pump and mixed into the primary continuous washing separation tower.

6. A tar distillation mixed fraction scrubbing system according to claim 1 wherein, The input end of the secondary continuous washing separation tower is provided with a secondary continuous washing pump, and the primary dephenol naphthalene oil in the primary dephenol buffer tank and the dilute alkali in the dilute alkali high tank are respectively pumped out by the secondary continuous washing pump and mixed into the secondary continuous washing separation tower.

7. A tar distillation mixed fraction scrubbing system according to claim 1 wherein, The water phase output end at the bottom of the secondary continuous washing separation tower is respectively connected with the input end of the basic phenate tank and the input end of the primary continuous washing pump. The output end of the neutral sodium phenate tank is connected with the input end of the evaporation and blowing still through a sodium phenate evaporation and blowing pump, and the liquid phase output end of the evaporation and blowing still is connected with the input end of the pure phenate tank. A heat exchanger is further arranged between the output end of the sodium phenate evaporation and blowing pump and the input end of the evaporation and blowing still, and a cooler is further arranged between the output end of the evaporation and blowing still and the input end of the pure phenate tank. The input end of the primary continuous washing separation tower is provided with a primary continuous washing pump, and the unwashed naphthalene oil in the unwashed naphthalene oil tank and the basic sodium phenate in the basic sodium phenate high tank are respectively pumped out by the primary continuous washing pump and mixed into the primary continuous washing separation tower. The input end of the secondary continuous washing separation tower is provided with a secondary continuous washing pump, and the primary dephenol naphthalene oil in the primary dephenol buffer tank and the dilute alkali in the dilute alkali high tank are respectively pumped out by the secondary continuous washing pump and mixed into the secondary continuous washing separation tower. The water phase output end at the bottom of the secondary continuous washing separation tower is respectively connected with the input end of the basic phenate tank and the input end of the primary continuous washing pump.

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