Development Of Environmental Friendly Heavy-duty LNG Engine Coolant

Liquefied natural gas(LNG)has the characteristics of large energy volume density,good storage and transportation performance and good safety.The advantage of LNG over liquid fuels such as gasoline and diesel is that it can significantly reduce vehicle emissions.At the same time,it can reduce fuel costs.The heavy-duty LNG gas engine cooling system not only cools the engine and ensures its normal operation,but also transfers the heat absorbed by the engine from liquid to gaseous fuel to supply the engine.Usually heavy-duty LNG engines need to run for a long time in close to the rated power conditions,with a high degree of reinforcement,long working time,large tonnage,combustion generated heat and so on.Therefore,heavy-duty LNG engines are very demanding on operating conditions,which are different from conventional fuel engines,especially on the performance of the coolant in the cooling system.By studying the present situation of heavy load engines at home and abroad and the characteristics of liquefied natural gas(LNG),combined with the performance requirements and actual operating conditions of heavy load liquefied natural gas(LNG).Develop a special coolant with good corrosion resistance,thermal stability,anti-foam,anti-boiling,anti-freeze and scale resistance,extend the service life,cooling effect outstanding and so on.In the process of development,the combined weighting-ideal point method was used to screen the base solution,and the composite of ethylene glycol and propylene glycol at volume ratio of 60:40 was selected as the base solution and then verified by the composite addition test.The test of other additives was selected and the best amount added by tests such as matching test and glass vessel corrosion test,and the test results were analyzed by MATLAB,ORIGIN9.0,linear regression,etc.Finally,using uniform design formula test and using network level analysis(ANP)to establish ANP hierarchy for the whole formula scheme,using its correlation and multiple influencing factors to determine its comprehensive weight,determine the formula G9 as the best formula,taking into account the corresponding sensitivity error,the weight results for optimization analysis and evaluation.Through the sensitivity error analysis,it can be seen that the network level analysis is very reliable for coolant optimization and evaluation,the scheme G9 formula sensitivity difference is obvious compared to other optional formulations,and scheme G9 is in line with the environmental friendly heavyduty LNG engine coolant formula.After comprehensive physical and chemical characteristics test,the developed coolant has good viscosity,cooling,corrosion resistance and biodegradability,and its comprehensive performance is good,which meets the prospect of research and development.