Comprehensive evaluation and sensitivity analysis of regeneration energy for acid gas removal plant using single and activated-methyl diethanolamine solvents

The absorption of acid gas using reactive amines is among the most widely used types of capturing technologies. However, the absorption process requires intensive energy expenditure majorly in the solvent regeneration process. This study simultaneously evaluated the regeneration energy of MDEA and PZ/MDEA solvents in terms of heat of absorption, sensible heat, and vaporization heat. Aspen Hysys version 8.8 simulation tool is applied to model the full acid gas removal plant for the chemical absorption process. The new energy balance technique presents around the absorption and desorption columns to bring a new perspective of energy distribution in the capturing of acid gas plants. Sensitivity analysis of regeneration energy and its three contributors is performed at several operation parameters such as absorber and stripper pressures, lean amine circulation rate, solvent concentration, reflux ratio, and CO₂ and H₂S concentrations. The results show that the heat of absorption of PZ/MDEA system is higher than that for MDEA system for the same operating conditions. The sensible heat is the main contributor in the required regeneration energy of MDEA solvent system. The simulation results have been validated against data taken from real plant and literature. The product specifications of our simulation corroborate with real plant data in an excellent approach; additionally, the profile temperature of the absorber and the stripper columns are in good agreement with literature. The overall results highlight the direction of the effects of each parameter on the heat of absorption, sensible heat, and vaporization heat.     

乙二胺气固相催化环合哌嗪的研究

本文系统地研究了以乙二胺为原料 ,在固定床反应器中常压合成哌嗪并联产三乙烯二胺的工艺。确定了用KCl改性的HZSM - 5型分子筛为该反应的催化剂。对反应的主要工艺参数进行了优化 ,当反应温度在 340℃～ 345℃范围内 ,原料液为 0 5(质量分数 )的乙二胺水溶液 ,进料量为 0 2mL min时 ,乙二胺的转化率接近 1 0 0 % ,哌嗪与三乙烯二胺的选择性分别在 35 %～ 75 %和 5 %～ 1 5 %之间变化     

Modeling the rate of corrosion of carbon steel using activated diethanolamine solutions for CO_2 absorption

A mechanistic model is developed to investigate the influence of an activator on the corrosion rate of carbon steel in the absorption processes of carbon dioxide(CO_2). Piperazine(PZ) is used as the activator in diethanolamine(DEA) aqueous solutions. The developed model for corrosion takes into consideration the effect of fluid flow,transfer of charge and diffusion of oxidizing agents and operating parameters like temperature, activator concentration, CO_2 loading and pH. The study consists of two major models: Vapor–liquid Equilibrium(VLE) model and electrochemical corrosion model. The electrolyte-NRTL equilibrium model was used for determination of concentration of chemical species in the bulk solution. The results of speciation were subsequently used for producing polarization curves and predicting the rate of corrosion occurring at the surface of metal. An increase in concentration of activator, increases the rate of corrosion of carbon steel in mixtures of activated DEA.     

CO2 capture into aqueous solutions of piperazine activated 2-amino-2-methyl-1-propanol

In this work, experimental data and a simplified vapor–liquid equilibrium (VLE) model for the absorption of CO₂ into aqueous solutions of piperazine (PZ) activated 2-amino-2-methyl-1-propanol (AMP) are reported. The purpose of the work was to find the AMP/PZ system with the highest concentration and cyclic capacity, which could be used in the industry without forming solid precipitations at operational temperatures. The effect of the AMP/PZ ratio and the total concentration level of amine was studied. The highest possible ratio of AMP/PZ, which does not form solid precipitates during the absorption of CO₂ at 40 °C (40 wt% amine), was identified. Considering the maximum loading found in the screening tests for AMP/PZ (3+1.5 M) and for 30 wt% MEA systems, the AMP/PZ system has about 128% higher specific cyclic capacity if operating between 40 and 80 °C, and almost twice the CO₂ partial pressure at 120 °C compared to MEA.     

哌嗪合成工艺及经济性分析

介绍了目前国内外合成哌嗪的方法,论述了由乙二胺和环丙乙烷合成哌嗪的路线,并作了技术经济性分析,为新技术的开发提供了初步依据。     

低压连续催化合成哌嗪

１前言哌嗪（ｐｉｐｅｒａｚｉｎｅ）是典型的六元环对二仲胺结构,是一种重要的医药中间体,可制造驱虫药、镇痛药、抗结核及抗菌类药物。哌嗪也可制成染整助剂、硫化促进剂、防腐剂、抗氧剂、稳定剂等,广泛应用于纺织、橡胶、精细化工等各个领域［１－５］。据文献报道...     

1—乙氧羰基哌嗪的合成

报道了由六水哌嗪与氯甲酸乙酯发生亲核取代反应制备１－乙氧羰基哌嗪的方法,并研究了其原料配比、反应温度及反应时间对产物收率的影响,在优化条件下,收率可达９７．６％。     

哌嗪的合成及用途

介绍了哌嗪的合成路线、用途及目前的市场状况。     

Amine Solutions for Biogas Upgrading: Ideal versus Non‐Ideal Absorption Isotherms

Amine solutions were applied in carbon dioxide removal from a model mixture of biogas, carried out in a loop reactor system. In addition, the effect of CO₂ absorption acceleration in the presence of piperazine was confirmed and quantified, relating the obtained CO₂ loading with the piperazine concentration. Further, the interactions of CO₂ and water in aqueous amine solutions were discussed. The obtained acid gas loadings were accurately described taking into account the effect of the dissolved CO₂ on the equilibrium constant. A logarithmic absorption isotherm that follows from such considerations and a saturation‐type isotherm were compared. In describing the experimental data, advantages and disadvantages of both approaches are discussed.     

Absorption of carbon dioxide into aqueous solutions of piperazine activated 2-amino-2-methyl-1-propanol

In this work, new experimental data on the rate of absorption of CO₂ into piperazine (PZ) activated aqueous solutions of 2-amino-2-methyl-1-propanol (AMP) are reported. The absorption experiments using a wetted wall contactor have been carried out over the temperature range of 298-313 K and CO₂ partial pressure range of 2-14 kPa. PZ is used as a rate activator with a concentration ranging from 2 to 8 wt%, keeping the total amine concentration in the solution at 30 wt%. The CO₂ absorption into the aqueous amine solutions is described by a combined mass transfer-reaction kinetics-equilibrium model, developed according to Higbie's penetration theory. Parametric sensitivity analysis is done to determine the effects of possible errors in the model parameters on the accuracy of the calculated CO₂ absorption rates from the model. The model predictions have been found to be in good agreement with the experimental results of rates of absorption of CO₂ into aqueous (PZ+AMP). The good agreement between the model predicted rates and enhancement factors and the experimental results indicates that the combined mass transfer-reaction kinetics-equilibrium model with the appropriate use of model parameters can effectively represent CO₂ mass transfer in PZ activated aqueous AMP solutions.