大连石化制氢装置加工天然气原料技术分析

An Analysis of Technology for Processing Natural Gas Feedstock in Dalian Petrochemical Company′s Hydrogen Plants

加速天然气的生产和消费,发展天然气化工,减轻对石油的需求压力,确保国家能源安全,已成为加速我国化学工业结构调整、强化节能减排的必然趋势。大连石化拥有两套完全独立的制氢装置,单套装置的公称产氢能力为10×104m3/h(标准),每一套装置都包括造气单元和PSA提纯单元。该装置加工的原料为轻石脑油或液化石油气,成本昂贵,操作费用大。提出利用低价、节能的天然气作为装置替代原料的设想。可行性分析认为,天然气基本不含烯烃,且芳烃和环烷烃含量低,氢气产率高,可以避免催化剂积炭,延长催化剂寿命,是制氢的首选原料;加之天然气富含甲烷,其H/C较高,一般在3.8左右,单位产氢量的原料消耗较少。大连石化制氢装置改为加工天然气后,原料精制单元,包括加氢反应器和脱硫反应器、中温变换单元和PSA氢气提纯单元的操作参数均不发生改变,可以大大降低装置的原料消耗和燃料消耗,同时提高了蒸汽的产出量,减少了CO2的排放。

Quickening the production and consumption of natural gas and developing natural gas-based chemical production to reduce the pressure on oil demand and ensure national energy security has become an approach that China must take in order to accelerate the adjustment to the structure of its chemical industry and to strengthen energy saving and emission reduction.PetroChina Dalian Petrochemical Company has two independent hydrogen production plants,each of which has a nominal hydrogen production capacity of 10×10^4m^3/h （standard） and has a gas production unit and a PSA unit.The plants use expensive naphtha or liquefied petroleum gas as feedstock and therefore the cost of operation of the two plants is very high.This article presents a plan to replace naphtha and LPG with relatively cheap and energy-etiicient natural gas as feedstock for the plants.Feasibility studies show that natural gas basically does not contain olefirr,contains on- ly small amounts of arene and naphthenic hydrocarbon,and has a high yield of hydrogen.In addition,the use of natural gas as feedstock can avoid carbon deposition on catalysts,thus extending the lives of catalysts, making the gas the best feedstock for making hydrogen.In addition,as natural gas has high contents of methane and the H/C of the gas is relatively high,usually at about 3.8,the consumption of feedstock for producing unit volume of hydrogen is lower.After PetroChina Dalian Petrochemical Company＇s hydrogen plants switch to natural gas ,the operating parameters of the feedstock rectification units of the plants, including the hydrogenation reactor,the desulfurization reactor,the intermediate temperature shift unit,and the PSA hydrogen purification unit,will all remain unchanged.This can greatly reduce the consumption of raw material and fuel for the plants,while increasing the production of steam and cutting CO2 emissions.