Application And Research Of Coal Water Slurry In A Steam Injection Boiler In Oil Field

Heavy oil Exploitation in Xinjiang oilfield is limited by two unfavorable factors,which are limited natural gas consumption and increasing price. Replacing natural gas with coal water slurry(CWS) as fuel is one of the choices to achieve fuel transition.Firstly, Four kinds of Xinjiang coal were chosen to conduct slurry performance, factors including coal quality, additives, water samples, sludge and particle size distribution were considered to explore their effect on the performance of CWS. We recommended Xukuang 3 (pulp slurry concentration 60-61%) as pulping coal. Y+02 which has good adaptability can be used as an additive. Water didn’t have a significant impact on slurry concentration of Xukuang 3 or Xukuang 6, the concentration slightly decreased(less than 1%). It was recommended to use water at the entrance of gravity removing oil device, which was named with ZCJ to make CWS. Boda sludge had the best effect on slurry performance of Xukuag 3, but it reduced the concentration of slurry and heat, this factor should be taken into account. With the increase of fine particles, the viscosity of CWS had an upward trend, which indicated that the role of fine particles in CWS is to increase viscosity. With the increase of temperature, viscosity of Xukuang 3 CWS decreased gradually.Secondly, TGA experiments were used to study the combustion characteristics of XuKuang 3. By carrying out TGA experiments of XuKuang 3 at different heating rates, we identified a number of combustion parameters of XuKuang 3, XuKuang 3 CWS and XuKuang 3 sewage CWS, and analyzed analyzed from the point of view of dynamics. With the increase of heating rate, peak dehydration temperature, combustion peak temperature, burn out temperature, maximum combustion rate, average combustion rate, combustion characteristic index of Xukuang 3 CWS showed a increasing trend, while the firing temperature changed a little, which was stabilized at about 400 ℃. From the point of view of combustion characteristics and thermal dynamic analysis, water at the entrance of gravity removing oil device wass absolutely feasible for making pulp, which had little even beneficial effects on combustion characteristics of Xukuang 3.Lastly, we discussed the results of the retrofitting and combustion test on a 7t/h mobile CWS steam injection boiler in oilfield. The results showed that the furnace temperature reached 1100～1200, the furnace combustion was stable, the combustion was complete, and the steam parameter was stable, which can reach 4.3Mpa,250℃. However, the fouling of stable combustion chamber was more serious, which was mainly vitreous body with high strength. The original furnace was mainly dominated by loose ash deposits, which can be partly swept. At the same time the pollutant emission characteristics showed that SO2 and NOx emissions were exceeding the allowable value of national standard, and desulfurization and denitrification and dust removal equipment is necessary to be added.