Production process for preparing calcium carbide from calcium coke pellets in graded oxygen heating mode

Abstract

The invention discloses a production process for preparing calcium carbide from calcium coke pellets in a graded oxygen heating mode. The production process comprises the steps that the calcium coke pellets with the particle size being 5 to 30 mm are added into a moving bed preheater through a feeder, are subjected to counterflow heat exchange with air combustion flue gas rising from the bottom to reach 600 to 1300 DEG C in temperature, and then flow into a kiln tail of a rotary kiln reactor under control of a plug valve at the bottom of the preheater; the hot calcium coke pellets are heated to 1400 to 1900 DEG C by coke powder and oxygen high-temperature flames blown by a kiln head in a rotary kiln with the inclination being 1.5 to 10 degrees and the rotating speed being 2.0 to 5.0 rpm, reaction is conducted to generate the calcium carbide and exhaust CO, and high-temperature reaction gas containing CO and H2 reversely flows to the kiln tail to be combined with the added air and coke powder for combustion to generate air combustion flue gas used for preheating; after flowing into a thermal insulation moving bed from a kiln outlet to be subjected to reinforced reaction for 5 to 90 minutes, the generated calcium carbide flows into a fine-toothed cooler from the bottom of the thermal insulation moving bed to be cooled to 100 DEG C or below to serve as a product, and heated inert gas is subjected to heat recovery and then pressurized and circulated back into the fine-toothed cooler for adsorbing heat; and air combustion gas at the top of the moving bed after exchange is subjected to heat recovery through an afterburning waste boiler and then exhausted out by an induced draft fan.

Description

[0001] 1. Technical field [0002] The invention provides a production process for preparing calcium carbide by a graded oxygen thermal method of calcium coke pellets, and relates to the field of coal chemical industry. [0003] 2. Background technology [0004] At present, acetylene is mainly produced on a large scale through the calcium carbide method, and is an important raw material for the organic synthesis industry. Calcium carbide is produced from quicklime and carbon through complex physical and chemical changes in a calcium carbide furnace. As a new type of carbon material, semi-coke is made of weakly caking or non-caking coal with high volatile content as a raw material, and is a solid product obtained by removing tar substances and most of the volatile content in coal through carbonization at medium and low temperatures. The characteristics of high fixed carbon, high resistivity, low ash content, low sulfur content, low phosphorus content and low price are gradually...

AI Technical Summary

Problems solved by technology

However, due to the structure of the reactor and the lack of consideration of the W-shaped change law of the calcium carbide melting point caused by the change in calcium carbide content, the technical route of calcium carbide produced by the oxythermal method is a liquid product like the electrothermal method, and the calcium-coke ratio is unreasonable, resulting in calcium carbide heat recovery. Difficult, raw material preheating still utilizes high-temperature CO as a by-product. Compared with foreign oxythermal processes, oxygen consumption and carbon consumption have not been significantly reduced, and no industrial pilot test and industrialization results have been seen so far.

[0007] The process of adding quicklime and coke in the current electric arc furnace heating process is cumbersome and complicated, and in the whole production and use process of limestone and semi-coke, there are always processes such as solid crushing, solid screening and solid transportation. A large amount of powdery quicklime semi-coke or coke less than 6mm will be produced, which needs to be utilized urgently

[0008] In addition, due to the shortage of high-quality limestone resources, the mining has seriously damaged the mountain environment, and the control of limestone mining in various places has become more and more strict, which has become the bottleneck of domestic quicklime production.

Images