[关键词]
[摘要]
针对现有船舶废气洗涤装置共存的开式系统海水脱硫效果不佳、闭式系统碱液消耗量大的问题提出了梯级洗涤技术,并在试验系统上测试了海水/海水梯级洗涤和海水/碱液梯级洗涤两种模式下的废气脱硫效果。结果表明:海水/海水梯级洗涤脱硫效率与海水碱度密切相关,采用高碱度海水脱硫时梯级洗涤法可以满足硫排放控制要求,但海水碱度低时则无法满足要求;海水/碱液梯级洗涤效果优于海水/海水梯级洗涤。当主洗涤段采用碱度为810 μmol/L、液气比为5 L/m3的海水洗涤SO2浓度为2 000 mg/m3的废气时,副洗涤段使用pH值为12.2的碱液且液气比为1 L/m3即可达到97.2%以上的脱硫效率,且碱液的pH值越高,洗涤效果越好。综合脱硫需求、泵耗和防腐需求,建议碱液pH值宜选11~13。
[Key word]
[Abstract]
Aiming at solving the deficiencies of the existing two desulfurization solutions (i.e.,the insufficient seawater desulfurization efficiency in Sulphur Emission Control Area (ECA) for the openloop solution and the large fresh water/sodium hydroxide consumption for the closedloop solution),a cascadescrubbing desulfurization technology coupled with seawater and alkaline liquor was proposed in this paper.Accordingly,a benchscale cascadescrubbing desulfurization system was established to perform desulfurization experiments respectively under operational models of cascaded seawater and cascaded seawater/alkaline,so as to confirm its desulfurization performance for the marine exhaust gas.Results showed that high desulfurization efficiency can be gained by the proposed seawater cascadescrubbing solution and the desulfurization efficiency strongly depends on the seawater alkalinity.In the seawater cascadescrubbing solution,only the circumstances with highalkalinity seawater can meet the ECA′s requirements.Again,the seawater/lye cascadescrubbing model is superior to the sole seawater cascadescrubbing model in the desulfurization performance.Under the seawater/lye cascadescrubbing conditions where the parameters in main scrubbing section are seawater alkalinity 810 μmol/L,liquid/gas ratio 5 L/m3,and inlet SO2 concentration 2 000 mg/m3,the subordinate scrubbing section (using a lye with the pH value of 12.2) reaches a sufficiently high desulfurization efficiency above 97.2%,with an extremely low liquid/gas ratio less than 1 L/m3.The higher the pH of the lye,the better the desulfurization performance.In view of an excessively high concentration lye deepening corrosion,sufficient desulfurization efficiency plus a low liquid/gas ratio for low cost necessitates the lye pH levels in the subordinate scrubbing section to be set at 11-13.
[中图分类号]
X511
[基金项目]
国家重点研发计划(2016YFC0205800);浙江省公益技术研究社会发展项目(2014C33008);浙江省新苗人才计划(2016R405075)