Study On Upgrading Process Of Raffinate Derived From Coal-to-glycol

Aiming at the comprehensive utilization of raffinate derived from coal-to-glycol, the paper studied the raffinate containing water, a low boiling point organic matter, easy hydrolysis esters and high boiling point alcohols. The raffinate obtained from the combination of submerged evaporation, activated carbon adsorption and ion exchange resin adsorption methods was applied for producing the raw material of ethylene glycol antifreeze. The investigation of technological parameters acquire the optimum technological conditions for the submerged evaporation of glycol raffinate, enriched glycol raffinate decoloring and taste removal and disacidify of enriched glycol raffinate, carrying out the conceptual design and preliminary evaluation of technology and economy.1. A submerged evaporation device was designed and the optimum operation conditions was obtained, the results were the gas flow of 45 mL/min, evaporativity of 62.5% and straight pipe of the immersion depth was located at two-thirds of the liquid level.2. The optimally decoloring and taste-removal technological conditions of enriched glycol raffinate were determined as the following:the adsorption time was 3 h, the temperature was 50℃, the oscillation frequency was 150 r/min, mixed the active carbon of sample 1 and enriched glycol residual liquid (10g:50mL). Thus, the decoloration rate of enriched glycol residual liquid was 95.48%. In addition, the activated carbon could be reused for four times at 300℃, and the decoloration rate was 92.35%.3. D311 resin was selected as the adsorbent for eliminating acid through the dynamic adsorption experiments, of which the pretreatment time has been optimized as the following:10% NaCl for 24h, 1mol/L HCl for 24h, 1mol/L NaOH for 24h. It was indicated that the optimum velocity of D311 resin was of 0.6 mL/min and the dosage of NaOH (1mol/L) was triple of the resinous volume.The conceptual design was determined on the basic of Lab test results, including technical flow, technical instructions, primary material and energy balances, and select of main equipment. The results of techno-economic preliminary evaluation demonstrated that the present project with economic, social and environmental benefits could be employed as one of strategies for the resource recycling of glycol raffinate.