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Method of producing thiourea using acidic waste gas discharged from oil refinery

An acid waste gas, refinery technology, applied in organic chemistry and other directions, can solve the problems of high cost of thiourea and environmental pollution by barium sulfide residues

Inactive Publication Date: 2003-09-17
LINZI WANTONG FINE CHEM PLANT ZIBO CITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The cost of thiourea in this method is high, and a large amount of barium sulfide residue pollutes the environment

Method used

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  • Method of producing thiourea using acidic waste gas discharged from oil refinery
  • Method of producing thiourea using acidic waste gas discharged from oil refinery

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] Directly use the acid waste gas discharged from the refinery and calcium cyanamide to produce thiourea; the composition of the acid waste gas discharged from the refinery in this batch is: hydrogen sulfide 60±5%, air 10±3%, carbon dioxide 3±0.5%, Ethane 2±0.5%, Methane 0.2±0.05%, Propylene 0.2±0.05%, Propane 0.09±0.02%, Ethylene 0.05±0.02%, Carbon Monoxide 0.09~±0.03%, The balance is trace butene, anti-butene, normal Butane and isobutane;

[0026] The specifications of calcium cyanamide are: effective nitrogen content 17.35%, calcium carbide content 1.0%, aperture 850μm sieve residue ≤ 3%, appearance black powder.

[0027] In the above method, its production process is divided into calcium hydrosulfide process, thiourea synthesis process and post-treatment process, wherein:

[0028] (1) Calcium Hydrosulfide Process

[0029] Raw material weight ratio calcium cyanamide: water = 550kg: 8000kg; put in water first, add calcium cyanamide under stirring, add to the generated...

Embodiment 2

[0045] Directly use the acid waste gas discharged from the refinery and calcium cyanamide to produce thiourea; the composition of the acid waste gas discharged from the refinery in this batch is: hydrogen sulfide 80±5%, air 20±2%, carbon dioxide 10±1%, Ethane 8±1%, Methane 0.5±0.1%, Propylene 0.4±0.05%, Propane 0.2±0.02%, Ethylene 0.2±0.01%, Carbon Monoxide 0.15±0.05%, The balance is trace butene, anti-butene, n-butene alkanes and isobutanes;

[0046] The specifications of calcium cyanamide are: effective nitrogen content ≥ 20%, calcium carbide content ≤ 0.2%, sieve residue ≤ 3% with aperture 850μm, appearance of black powder.

[0047] (1) Calcium Hydrosulfide Process

[0048] Raw material weight ratio calcium cyanamide: water / thiourea synthesis process lotion = 650kg: 8000kg; the acid waste gas discharged from the refinery is passed into the acid waste gas discharged from the refinery under stirring at 70-80°C, and the calcium hydrosulfide content in the reaction solution re...

Embodiment 3

[0053] Directly use the acid waste gas discharged from the refinery and calcium cyanamide to produce thiourea; the effective nitrogen content of calcium cyanamide is ≥19%, the content of calcium carbide is ≤0.5%, and the sieve residue with an aperture of 850 μm is ≤3%; calcium cyanamide: Thiourea synthesis process lotion = 600kg: 8000kg; 80 ~ 90 ° C under stirring to produce calcium hydrosulfide; thiourea synthesis calcium hydrosulfide: calcium cyanamide = 1: 1.1 (molecular ratio); Stir at 80 ~ 90 ° C Next, react for 3h to synthesize thiourea; the rest are the same as in Example 1.

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Abstract

A process for preparing the thiourea from the acidic waste gas exhausted from oil refinery features the reaction of said acidic waste gas on calcium cyanoamide. The said acidic waste gas contains hydrogen sulfide, air, CO2, ethane, methane, etc. The said calcium cyanoamide is a black powder containing effective nitrogen (greater than or equal to 17-20%) and calcium carbide (less than or equal to 0.2-1.0%). Its advantages are use of waste as raw material for lower cost, and high quality of product.

Description

technical field [0001] The invention belongs to the category of comprehensive utilization of three wastes, and in particular relates to a method for producing thiourea by using acid waste gas discharged from an oil refinery. Background technique [0002] The acid waste gas discharged from the refinery contains a large amount of hydrogen sulfide. At present, Claus sulfur recovery is usually used, that is, the acid gas containing hydrogen sulfide is burned under controlled air, and the hydrogen sulfide is burned into Sulfur dioxide, under the action of high temperature and catalyst, sulfur dioxide reacts with unburned hydrogen sulfide to form sulfur; this method is not economically beneficial to recover sulfur. [0003] The conventional synthesis of thiourea (Tiourea) process is to use barium sulfide and acid to generate hydrogen sulfide gas, then react with calcium hydroxide to generate calcium hydrosulfide, and then react with calcium cyanamide to generate thiourea. The cos...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C335/02
Inventor 高庆昌徐志平李凤林
Owner LINZI WANTONG FINE CHEM PLANT ZIBO CITY
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