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Calcium carbide preparation method

A calcium carbide and rotary kiln technology, applied in the direction of carbide, calcium carbide, etc., can solve the problems of reducing product purity, high cost of additive lithium carbonate, difficult to recover molten calcium carbide phase change heat, etc., so as to reduce equipment investment and operating costs. , Save energy consumption and cost of crushing, and realize the effect of energy cascade utilization

Inactive Publication Date: 2018-04-27
BEIJING UNIV OF CHEM TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

In this method, the additive forms a liquid phase between the carbon-containing raw material and the calcium-containing raw material, promotes the mass transfer of the raw material, can reduce the reaction temperature, but at the same time inevitably reduces the product purity, and it is difficult to recover the phase change heat of molten calcium carbide. And the cost of lithium carbonate as an additive is relatively high

Method used

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  • Calcium carbide preparation method

Examples

Experimental program
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Effect test

Embodiment 1

[0038] figure 1 , figure 2 with image 3 Prepare the schematic flow sheet of calcium carbide for the present invention, wherein, figure 1 The heat source of the first-stage rotary kiln is the sensible heat of the gas supplied to the second-stage rotary kiln, and the heat source of the second-stage rotary kiln is the sensible heat of the gas generated by the reaction in the third-stage rotary kiln; figure 2 The heat source of the first-stage rotary kiln is the combustion heat of the gas supplied to the second-stage rotary kiln; the heat source of the second-stage rotary kiln is the sensible heat of the gas generated by the reaction in the third-stage rotary kiln; image 3 The heat source of the first-stage rotary kiln is the sensible heat of the combustion gas after heating the second-stage rotary kiln; the heat source of the second-stage rotary kiln is the combustion heat of the gas generated by the reaction in the third-stage rotary kiln.

[0039] The concrete steps of p...

Embodiment 2

[0045] Coal coke (8% ash content, particle size less than 500 mesh) and calcium carbide slag (7% non-calcium impurities, particle size less than 500 mesh) are used as raw materials, and the mass ratio of coal and calcium carbide slag is 0.9:1. The kiln tail of the first-stage rotary kiln, and then the raw materials slowly move to the kiln head, and are discharged from the kiln head after 30 minutes; during the movement, the raw materials are heated to Perform pyrolysis at 700°C to obtain pyrolysis materials, and collect the generated pyrolysis gas and tar by-products;

[0046] The pyrolysis material enters the kiln tail of the second-stage rotary kiln through the heat conveying device, slowly moves to the kiln head, and is discharged from the kiln head after 15 minutes; during the moving process, the gas generated by the third-stage rotary kiln is used to heat up to 1000°C for pretreatment. Heat, get preheated material;

[0047] The preheated material enters the third-stage r...

Embodiment 3

[0050] Coal (ash content 8%, particle size less than 20 mesh) and limestone (non-calcium impurities 4%, particle size less than 100 mesh) are used as raw materials, and the mass ratio of coal and limestone is 0.5:1. After mixing and granulating into 10mm spherical particles Add the kiln tail of the first-stage rotary kiln, and then the raw material slowly moves to the kiln head, and is discharged from the kiln head after 60 minutes; the raw material is produced by the third-stage rotary kiln during the movement process and is heated by the second-stage rotary kiln. The gas is heated to 900°C for pyrolysis to obtain pyrolysis materials, and the generated pyrolysis gas and tar by-products are collected;

[0051] The pyrolysis material enters the kiln tail of the second-stage rotary kiln through the heat conveying device, slowly moves to the kiln head, and is discharged from the kiln head after 25 minutes; during the moving process, the gas generated by the third-stage rotary kiln...

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Abstract

The invention provides a three-stage rotary kiln method for preparing calcium carbide. The method includes: heating a carbon-containing raw material and a calcium-containing raw material in a first-stage rotary kiln to 600-900 DEG C for pyrolysis; conveying into a second-stage kiln in a hot state, and preheating to 1000-1350 DEG C; conveying the preheated raw materials into a third-stage rotary kiln in a hot state; heating to 1500-1800 DEG C for reaction to produce solid-state calcium carbide. Compared with high-temperature arc processes, the method has the advantages that reaction temperatureand energy consumption for calcium carbide production are lowered, discharging is easy to perform, energy consumption for breaking calcium carbide in a molten state after solidification is omitted, equipment investment and running cost are lowered, and energy is saved by 30-46% in total. In addition, purity of calcium carbide prepared by the method is up to 93%, and conversion rate of CaO in thecalcium-containing raw material reaches 99%.

Description

technical field [0001] The invention relates to a method for preparing calcium carbide, belonging to the technical field of chemical production. Background technique [0002] Calcium carbide, commonly known as calcium carbide (CaC 2 ), was once known as the mother of organic synthesis. At present, it is mainly used in the production of vinyl chloride, vinyl acetate and acrylonitrile. In 2016, my country's calcium carbide output was 27.3 million tons. [0003] At present, the production method of calcium carbide for industrial use is the high temperature arc method. In the method, coke with a particle size range of 5-30mm and excess calcium oxide of about 10-15% are heated to 2000-2200° C. in an electric arc furnace, and after reacting for 1-2 hours, the product is discharged in a molten state. Pure CaC 2 The melting point of CaO is about 2300°C, the melting point of CaO is about 2572°C, and the industrial product is CaC 2 A low temperature eutectic with CaO (CaC 2 -Ca...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B32/942
CPCC01P2004/60C01P2006/80
Inventor 刘振宇刘清雅李正科
Owner BEIJING UNIV OF CHEM TECH
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