Treatment method and treatment system of tail gas from glyoxylic acid production by nitric acid oxidation of glyoxal

A technology for treating glyoxal, nitric acid and tail gas is applied in the fields of energy saving, consumption reduction and environmental protection, and can solve the problems of high energy consumption, low recovery rate of useful substances, complicated process steps for tail gas treatment, etc. The effect of low maintenance cost and raw material saving

Active Publication Date: 2011-11-23
HUBEI HONGYUAN PHARMA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The present invention aims to solve the problem that the tail gas treatment process containing nitrogen oxides and hydrogen chloride in the prior art is not connected with the generation reaction of the tail gas, and the useful substances recovered in the tail gas treatment process are not returned to the generation reaction of the tail gas, and the tail gas treatment process steps are cumbersome, Technical problems of high energy consumption and low recycling rate of useful substances in tail gas

Method used

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  • Treatment method and treatment system of tail gas from glyoxylic acid production by nitric acid oxidation of glyoxal
  • Treatment method and treatment system of tail gas from glyoxylic acid production by nitric acid oxidation of glyoxal
  • Treatment method and treatment system of tail gas from glyoxylic acid production by nitric acid oxidation of glyoxal

Examples

Experimental program
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Effect test

Embodiment 1

[0044] The discharge from the oxidation reactor contains NO x and the tail gas of HCl, the induced draft fan at the end of the seventh stage alkali absorption tower (gas flow 9500m 3 / h) Under the action of negative pressure (-0.003MPa) produced, the air (containing 21% O 2 ) after mixing, enter the series first to sixth water absorption towers for water absorption, and remove most of the NO and NO in the tail gas 2 and HCl gas into a mixed acid solution containing nitric acid and a small amount of hydrochloric acid. Then, adjust the mixed acid solution extracted from the first-stage water absorption tower with concentrated nitric acid to make its concentration reach 45% (mass percentage), and then return to the oxidation reactor for circulation reaction. The absorption temperature of the first stage to the sixth stage water absorption tower is controlled at 35°C. The tail gas after the sixth-stage water absorption tower enters the seventh-stage lye absorption tower, and re...

Embodiment 2

[0047] Technological process is identical with example 1, and technological index is adjusted as follows:

[0048] The gas flow rate of induced draft fan is 9000m 3 / h, pressure-0.004MPa in the oxidation reactor still, the mixed acid concentration of the first stage water absorption tower absorption end point is 30% (mass percentage), adjusts its concentration with concentrated nitric acid and reaches 40% (mass percentage) after applying mechanically to the oxidation main reaction. The absorption temperature of the first stage to the sixth stage water absorption tower is 25 ℃, and the seventh stage alkali liquor absorption tower adopts 30% (mass percentage) Na 2 CO 3 The solution is absorbed, the pH value of the lye absorption end point is 10.0-11.0, and the pH value of the neutralization end point is 7.0.

[0049] After the above process is completed, the tail gas is finally discharged from the outlet of the induced draft fan, and the NO in the tail gas x and the total co...

Embodiment 3

[0051] Technological process is identical with example 1, and technological index is adjusted as follows:

[0052] Induced fan gas flow 10000m 3 / h, pressure-0.005MPa in the oxidation reactor still, the mixed acid concentration of the first stage water absorption tower absorption end point is 25% (mass percentage), adjusts its concentration with concentrated nitric acid and reaches 35% (mass percentage) after applying mechanically to the oxidation main reaction. The absorption temperature of the first stage to the sixth stage water absorption tower is 20 ℃, and the seventh stage lye absorption tower adopts 25% (mass percentage) NaOH solution to absorb, and the pH value of the lye absorption end point is 10.5-11.5, medium And the pH of the end point is 7.0.

[0053] After the above process is completed, the tail gas is finally discharged from the outlet of the induced draft fan, and the NO in the tail gas x and the total content of HCl is 185ppm, of which NO x The content o...

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Abstract

A treatment method and a treatment system of tail gas from glyoxylic acid production by nitric acid oxidation of glyoxal belong to the fields of environmental protection, energy saving and consumption reduction. The method comprises the following steps: introducing air to oxidize NO in tail gas generated by nitric acid oxidation of glyoxal into NO2; performing six-grade water absorption continuously to absorb gas of NOx and HCl in the tail gas; absorbing the tail gas after six-grade water absorption by a NaOH or Na2CO3 solution to remove residual NO2 and HCl gas and to generate an alkaline solution containing NaNO3, NaNO2, and trace NaCl; discharging the treated tail gas by an induced draft fan; performing neutralization, concentration, crystallization, centrifugation and separation of the generated alkaline solution to obtain a mixed sodium salt containing NaNO3, NaNO2, and trace NaCl, returning the mixed sodium salt to an oxidation vessel to be used as a catalyst for recycle. The treatment system comprises: an oxidation reaction vessel, water absorbing towers from grade one to grade six, a seventh grade alkaline solution absorbing tower, a concentration and crystallization vessel, a centrifuge, and a induced draft fan.

Description

technical field [0001] The invention relates to a tail gas treatment method for nitrogen oxides and hydrogen chloride produced from glyoxylic acid by oxidation of glyoxal nitric acid and a treatment system required for implementing the process, belonging to the fields of environmental protection, energy saving and consumption reduction. Background technique [0002] Glyoxylic acid is an important organic chemical raw material, which is widely used in the synthesis of light industrial products such as spices, medicines, pesticides, papermaking, coatings, paints, leather and food additives. Glyoxylic acid production methods can be divided into two categories: chemical synthesis and electrochemical synthesis. The most commonly used in industry are glyoxal nitric acid oxidation and maleic acid (anhydride) ozone oxidation. Among them, the glyoxal nitric acid oxidation method uses nitric acid as an oxidant to selectively oxidize glyoxal. This method has mild reaction conditions, s...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D53/75B01D53/76B01D53/78B01D53/56B01D53/68
CPCY02A50/20
Inventor 鲍应元段小六邓支华彭秋知晏浩哲周拥军
Owner HUBEI HONGYUAN PHARMA
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