Natural gas heavy hydrocarbon removal unit and mercury removal unit are two common equipment in natural gas processing. Feed gas heavy hydrocarbon removal unit1）System functionHeavy hydrocarbons and aromatic hydrocarbons in natural gas will also solidify at low temperature, so they must be removed. The unit adopts activated carbon adsorption method to remove heavy hydrocarbons and aromatic hydrocarbons. In this unit, two same adsorption towers are used to adsorb heavy hydrocarbons and aromatic hydrocarbons. TSA method is used to analyze the heavy hydrocarbons and aromatic hydrocarbons in activated carbon. At the same time, condensation method is used to condense and separate the heavy hydrocarbons and aromatic hydrocarbons desorbed from the adsorbent. 2）Design parametersFeed gas processing capacity: 5 mmscfdAdsorption pressure 4.4MPa.GDesign point of heavy hydrocarbon in feed gas ≤ 1000ppmvAdsorption temperature ~ 40 ℃Regeneration pressure 4.2MPa.GRegeneration temperature 180 ~ 280 ℃Regenerative heat source high temperature heat transfer oilThe content of heavy hydrocarbon and aromatic hydrocarbon in purified gas shall be ≤ 10ppm respectively 3）Scope of adaptationThe load regulation range is 50 ~ 110%. 4）Process flow descriptionThe natural gas from the feed gas drying unit first enters from the top of the heavy hydrocarbon removal tower through the differential pressure control valve. After removing the heavy hydrocarbon through the adsorption of the activated carbon bed, it comes out from the bottom of the heavy hydrocarbon removal tower. After removing the heavy hydrocarbon, the content of aromatic hydrocarbon in the natural gas is ≤ 10ppmv, and then enters the mercury removal and dust filtration unit. The heavy hydrocarbon removal unit is equipped with two heavy hydrocarbon removal towers. Within a given adsorption cycle, one is in the adsorption state to remove the heavy hydrocarbons in the feed gas, and the second is in the regeneration (heating and cold blowing) state to desorb the aromatic hydrocarbons in the activated carbon. When the heavy hydrocarbon removal tower in the adsorption state is saturated, switch to the heavy hydrocarbon removal tower that completes regeneration. The saturated heavy hydrocarbon removal tower is followed by heating regeneration cycle and then cooling. The regeneration gas is obtained from the front of the differential pressure control valve. The regeneration gas enters the regeneration gas heating furnace and is heated to 220 ~ 280 ℃. The hot and dry gas desorbs the aromatic hydrocarbons in the activated carbon from top to bottom through the regeneration (heating) heavy hydrocarbon removal tower. The regeneration gas containing aromatic hydrocarbons from the heavy hydrocarbon removal tower in regeneration state (heating) enters the regeneration gas cooler for continuous cooling, and then separates the possible condensed aromatic hydrocarbons in the separator, and the condensed liquid enters the fuel gas separator. The gas from the top of the regeneration gas separator enters the adsorption tower in the adsorption state together with the feed natural gas behind the differential pressure control valve. Feed gas mercury removal and filtration unit1）Process descriptionThe natural gas from the feed gas drying and heavy hydrocarbon removal unit enters the sulfur impregnated activated carbon adsorber. Mercury reacts with the sulfur on the sulfur impregnated activated carbon to generate mercury sulfide, which is adsorbed on the activated carbon, so as to achieve the purpose of mercury removal. The mercury content of natural gas from mercury remover is less than 0.01μg/Nm3。One mercury remover is set, and the sulfur impregnated activated carbon is replaced according to the detection.The filter unit is equipped with a filter, which can be switched according to the resistance data to achieve the purpose of filtering molecular sieve and activated carbon dust.After dust removal, the dust particles in the feed gas are less than 10μm。The main equipment is mercury remover and dust filter. 2）Design parametersFeed gas processing capacity： 5 mmscfd Operating pressure: 4.4MPa.GAdsorption temperature： 45 ℃Content of Hg in purified gas ≤ 0.01μg/Nm3Dust content in purified gas ≤ 5μm