This paper described the emission situation of pollutants from coal combustion in China, and it was pointed out that the removal technology of fine particulate matter was an important goal to be solved urgently. The research progress of soot control technology for coal burning at home and abroad was reviewed, and the principle, characteristics and research progress of the smoke and dust control technology were introduced. The results show that low⁃low temperature electric dust removal technology, agglomeration technology and synergistic removal technology have become the hot spots of fine particulate emission control technology and have a good application prospect. In addition, the analysis points out the difficulties faced by each part and the development direction, and provides reference for the removal of fine particulate matter from smoke and dust to meet the requirement of ultra⁃low emission standard.

Microbes can improve the fluidity of waxy crude oil and increase the efficiency of transportation. The cultured Bacillus subtilis 6# and Pseudomonas aeruginosa 3# were mixed and cultured in a ratio of 2∶3, the growth conditions were optimized. DSC, polarizing microscope, HAKEE rheometer and interfacial tensiometer were used to analyze the effect of compound bacteria and waxy crude oil. The results showed that: after treatment with compound bacteria, the wax precipitation point of waxy crude oil decreased by 2.23 ℃, the peak point of wax precipitation decreased by 2.71 ℃, and the wax content of crude oil decreased by 51.64%; the wax crystal structure changed significantly; the apparent viscosity of crude oil decreased by 64.72% at 37 ℃. In addition, the emulsification index of the compound bacteria on liquid paraffin was 55.39%, and the surface tension of the liquid paraffin culture medium was reduced from 79.89 mN/m to 38.83 mN/m. Compared with single bacteria, compound bacteria are more effective in removing wax and reducing viscosity, and have wider application prospects.

Microbial paraffin removal and prevention has the advantages of low cost, safe operation and no damage to the formation. The effects of complex environment on microbial degradation were introduced, the effects of microbial degradation enzymes were analyzed,the effects of organic solvents and biological surfactants produced by microorganisms on the degradation of waxy crude oil were elaborated. Based on this, it is pointed out that the microbial technology should strengthen the research on the production mechanism of microbial degradation enzyme, organic solvent and surfactant, so that the microbial degradation of waxy crude oil has a broader application prospect

With the rapid development of economy and the increasingly stringent emission standards, the removal of dust has been a research hotspot. A new type of grounding atomization corona discharge precipitator is designed. During the discharge process, the liquid on the surface of the wire electrode is atomized while the particles are charged, so as to effectively remove the dust. During the experiment, the velocity of air flow is set to 1 m/s and 3 m/s, the flow rate and direction of air flow are changed, and the V⁃A characteristics of atomized negative corona discharge are studied. Secondly, the influence of gas velocity on dust removal efficiency in grounding atomization corona discharge precipitator with 25 mL/min flow rate of the liquid covered on the surface of the wire electrode is studied. Finally, in order to study the dust removal ability for high specific resistance dust by grounding electrode atomization corona discharge technology, cement dust with specific resistance of 1.2×1012 Ω·m is used as high specific resistance dust in reverse gas flow with gas velocity of 1 m/s. The results show that the dust removal efficiency decreases with the increase of gas velocity. The discharge current with the reverse gas flow is larger than that of the forward gas flow when the gas velocity is increased. When the flow rate of the liquid covered on the surface of the wire electrode is 25 mL/min, the current of the negative grounding atomization corona discharge is the largest.The optimum reaction conditions of the grounding atomization corona discharge precipitator are as follows: the flow rate of the liquid covered on the surface of the wire electrode is 25 mL/min when the reverse gas flow rate is 1 m/s. Compared with the traditional dry corona discharge reactor, the grounding atomization corona discharge precipitator has higher dust removal efficiency for high specific resistance dust.

The small groove surface flowing in the direction can effectively reduce the wall friction and reduce the energy consumption of transportation. For the gas pipeline with triangular ribs on the inner surface, the large eddy simulation is used to simulate different flow states, and the flow field velocity vector diagram, root mean square velocity profile line and Reynolds shear stress are analyzed. The simulation results show that the best drag reduction effect is achieved when the dimensionless dimension s+=20.7; the vortex formed by the turbulence is cut by the rib peak when passing through the rib to form a small reverse small vortex in the rib, and the fluid is the sliding friction between the wall surfaces which is converted into rolling friction, which reduces the frictional resistance; the velocity profiles of smooth tube wall, rib peak and valley bottom surface only differ greatly near the wall surface, and tend to be consistent far from the wall surface, and the rib pair the influence of the flow field mainly occurs in the near wall area.

According to the principle of atomizing corona discharge, a cooking fume purifier was made, and the volt-ampere characteristic curve of atomization condition and non-atomization condition, purification efficiency and discharge current were studied. The results showed that the discharge current of atomizing corona discharge was higher than the non atomizing corona discharge current, either positive or negative corona discharge; it was not conducive to the purification of earthed negative corona discharge cooking fume purification weather the flow too large or too small; cooking fume purifier efficiency were decreased with the increase of wind speed under both condition; the efficiency and the discharge current of atomizing corona discharge cooking fume purifier was almost unchanged with the increase of application time, while both of them decrease under the non-atomizing corona.

By using two forms of magnetic field to have an effect on negative corona discharge, the influence of magnetic field on different interelectrode area of corona discharge was studied. The research showed that the charging intensity is changed and the discharge current is increased when the magnetic field is applied to the corona zone. But the discharge current is not changed when the magnetic field is applied to the charging region. This well explained the reasons for the increase of the discharge current. Meanwhile, the research shows that the onset voltage of negative corona discharge is decreased when the magnetic field is applied. The main reason is due to that the electric field intensity of the corona region is enhanced when the magnetic field is applied.