CN-121971886-A - Ethylene byproduct post-treatment system and process

CN121971886ACN 121971886 ACN121971886 ACN 121971886ACN-121971886-A

Abstract

The invention relates to the technical field of post-treatment of byproducts in chemical production, in particular to a post-treatment system and a post-treatment process of ethephon byproducts: the device comprises a primary distillation unit, a neutralization extraction unit and a dehydration and drying unit which are sequentially connected, wherein the neutralization extraction unit is formed by adopting multistage serial continuous centrifugal extraction equipment, instantaneous efficient mixing and thorough separation of dichloroethane and washing water/alkaline washing liquid are forcedly realized through high-speed centrifugal force, and the bottleneck of incomplete separation is solved. And the material flows from the first stage to the N stage, the washing water flows reversely from the N stage to the 1 st stage, and the alkali liquor is precisely injected in the N-1 st stage, so that the efficient countercurrent extraction is formed, the impurity removal efficiency is greatly improved, the subsequent rectification is not needed, and the flow is simplified. Meanwhile, the neutralization and extraction unit realizes the separation effect which can be achieved by the traditional technology through huge equipment by using a compact serial modularized structure, and the equipment investment and the space cost are obviously reduced.

Inventors

XU JINGRUI
WAN JINFANG
Lv Yonghuan
HUANG JIN
LI JIE
HU SHUO
ZHU JUNJIE
ZHU XUEJUN
TANG SURONG
FENG XILIANG

Assignees

安道麦安邦(江苏)有限公司

Dates

Publication Date: 20260505
Application Date: 20260119

Claims (8)

1. A post-treatment system for ethephon byproducts is characterized in that, The device comprises a primary distillation unit, a neutralization extraction unit and a dehydration drying unit which are sequentially connected, wherein the neutralization extraction unit comprises a plurality of stages of continuous centrifugal extraction equipment which are sequentially connected in series, the number N of the continuous centrifugal extraction equipment is more than or equal to 3, and each stage of continuous centrifugal extraction equipment is provided with a heavy phase inlet, a heavy phase outlet, a light phase inlet and a light phase outlet; The heavy phase inlet of the continuous centrifugal extraction equipment of the first stage is connected with a dichloroethane feeding main pipe, and the heavy phase outlet of the continuous centrifugal extraction equipment of the N stage is connected with a dichloroethane discharging main pipe; The heavy phase inlet of the continuous centrifugal extraction device of each stage is connected with the heavy phase outlet of the continuous centrifugal extraction device of the previous stage except the first stage; The light phase inlet of the continuous centrifugal extraction equipment of the N level is connected with a washing water feeding main pipe, and the light phase outlet of the continuous centrifugal extraction equipment of the first level is connected with a separating wastewater discharging main pipe; the light phase outlet of the continuous centrifugal extraction device of the N-th stage is connected to the light phase inlet of the continuous centrifugal extraction device of the N-2 th stage, the light phase inlet of the continuous centrifugal extraction device of the N-1 th stage is connected with an alkaline washing liquid feeding main pipe, and the light phase outlet of the continuous centrifugal extraction device of the N-1 th stage is connected with a separation wastewater discharging main pipe.
2. The ethephon by-product aftertreatment system of claim 1, wherein the system further comprises a third processor configured to, The light phase inlet of the continuous centrifugal extraction apparatus of each of the remaining stages except the continuous centrifugal extraction apparatus of the nth stage and the N-1 th stage is connected to the light phase outlet of the continuous centrifugal extraction apparatus of the next stage thereof.
3. The ethephon by-product aftertreatment system of claim 2, wherein, The light phase outlet of the continuous centrifugal extraction equipment of the N-1 level is provided with a pH on-line monitor, the alkaline washing liquid feeding main pipe is provided with a flow regulating valve, and the pH on-line monitor is in signal connection with the flow regulating valve to form a closed loop control loop for regulating the flow of the alkaline washing liquid.
4. The ethephon by-product aftertreatment system of claim 3, wherein the system further comprises, The primary distillation unit comprises a rectification tower and a condenser, the condenser is arranged at the top of the rectification tower, a feed inlet of the rectification tower is used for receiving a coarse dichloroethane product, and a discharge outlet of the condenser is connected with the dichloroethane feed header pipe.
5. The ethephon by-product aftertreatment system of claim 4, wherein, The dehydration drying unit comprises a first transfer pump, a drying tower, a second transfer pump and a product storage tank, wherein an inlet of the first transfer pump is connected with the dichloroethane discharging main pipe, an outlet of the first transfer pump is connected with a feeding port of the drying tower, a discharging port of the drying tower is connected with an inlet of the second transfer pump, and an outlet of the second transfer pump is connected with the product storage tank.
6. The ethephon by-product aftertreatment system of claim 5, wherein, The number N of successive centrifugal extraction devices is preferably 5 stages.
7. An ethephon by-product post-treatment process applied to the ethephon by-product post-treatment system as claimed in claim 6, comprising the steps of: primary distillation and weight removal, namely feeding a byproduct dichloroethane crude product generated in the production process of ethylene into a primary distillation unit, and obtaining a dichloroethane primary distillation liquid after removing heavy components by distillation; feeding the obtained dichloroethane primary distillate into the neutralization extraction unit through the dichloroethane feed header pipe, and simultaneously feeding washing water and alkaline wash liquid into the neutralization extraction unit through the washing water feed header pipe and the alkaline wash liquid feed header pipe respectively, so that the dichloroethane, the counter-current flowing washing water and the alkaline wash liquid continuously perform countercurrent contact, mixing, reaction and centrifugal separation in the multistage serial continuous centrifugal extraction equipment, and refined dichloroethane is obtained from the heavy phase outlet of the Nth stage continuous centrifugal extraction equipment; And (3) dehydration and drying, namely sending the obtained refined dichloroethane into the dehydration and drying unit for dehydration treatment to obtain a high-purity dichloroethane product.
8. The process for the aftertreatment of ethephon by-products according to claim 7, characterized in that, In the continuous centrifugal extraction refining step, the alkali washing liquid is sodium hydroxide aqueous solution, and the mass concentration of the alkali washing liquid is 5-15%.

Description

Ethylene byproduct post-treatment system and process Technical Field The invention relates to the technical field of post-treatment of byproducts in chemical production, in particular to a post-treatment system and a post-treatment process of ethephon byproducts. Background During the production of ethephon, 1, 2-dichloroethane is produced as a by-product. The crude dichloroethane typically contains impurities such as hydrogen chloride (HCl), chloroethanol, ethylene oxide, and the like. In order to improve the economic value, the product needs to be refined and purified to meet the requirements of related quality standards and reach the grade of first grade. At present, the traditional post-treatment process of the crude dichloroethane generally comprises the steps of removing heavy components from the crude dichloroethane by a rectifying tower, sequentially washing the condensed distillate by a neutralization tank (alkali washing) and a water washing layering tank to neutralize and remove HCl and other acidic or water-soluble impurities, dehydrating the crude dichloroethane by a drying tower, and refining the crude dichloroethane by the rectifying tower to obtain the product. The process has the problems that the neutralization and the water washing processes are carried out in kettle type or tank type equipment, the material residence time is limited, the mass transfer efficiency is low, the dichloroethane and the water have certain intersolubility, the dichloroethane and the water are settled and layered only by gravity, and the separation effect is poor. Increasing the equipment size or series number to increase the process results in a significant increase in floor space and investment costs, and may present a marginal bottleneck. The purity of the dichloroethane obtained by the conventional process can only reach about 97.5%, and the content of the impurities such as chloroethanol, ethylene oxide and the like is high and can only be evaluated as second class products, so that the economic benefit is limited. Accordingly, there is a need to develop a post-treatment process and system that is more efficient, compact and capable of stably producing high quality dichloroethane. Disclosure of Invention The invention aims to provide a system and a process for post-treatment of ethephon byproducts, which solve the problems that the traditional post-treatment process of crude dichloroethane is low in mass transfer and separation efficiency, the product quality is improved, the process flow cannot be further optimized, and excessive equipment and space cost are required for achieving the same treatment effect. In order to achieve the above purpose, the invention provides an ethephon byproduct post-treatment system, which comprises a primary distillation unit, a neutralization extraction unit and a dehydration drying unit which are sequentially connected, wherein the neutralization extraction unit comprises a plurality of stages of continuous centrifugal extraction equipment which are sequentially connected in series, the number N of the continuous centrifugal extraction equipment is more than or equal to 3, and each stage of continuous centrifugal extraction equipment is provided with a heavy phase inlet, a heavy phase outlet, a light phase inlet and a light phase outlet; The heavy phase inlet of the continuous centrifugal extraction equipment of the first stage is connected with a dichloroethane feeding main pipe, and the heavy phase outlet of the continuous centrifugal extraction equipment of the N stage is connected with a dichloroethane discharging main pipe; The heavy phase inlet of the continuous centrifugal extraction device of each stage is connected with the heavy phase outlet of the continuous centrifugal extraction device of the previous stage except the first stage; The light phase inlet of the continuous centrifugal extraction equipment of the N level is connected with a washing water feeding main pipe, and the light phase outlet of the continuous centrifugal extraction equipment of the first level is connected with a separating wastewater discharging main pipe; the light phase outlet of the continuous centrifugal extraction device of the N-th stage is connected to the light phase inlet of the continuous centrifugal extraction device of the N-2 th stage, the light phase inlet of the continuous centrifugal extraction device of the N-1 th stage is connected with an alkaline washing liquid feeding main pipe, and the light phase outlet of the continuous centrifugal extraction device of the N-1 th stage is connected with a separation wastewater discharging main pipe. Wherein the light phase inlet of the continuous centrifugal extraction apparatus of each of the remaining stages except the continuous centrifugal extraction apparatus of the nth stage and the N-1 th stage is connected to the light phase outlet of the continuous centrifugal extraction apparatus of the next stage thereof. The light phase ou