Review

In the context of gas stations, phenolic wastewater has always been an environmental challenge that has hindered their development. Many experts have conducted long-term research and discussions on over a dozen phenolic wastewater treatment methods, including steam chemical dephenolization, steam dephenolization, solvent extraction dephenolization, resin dephenolization, sulfonated coal adsorption, and biochemical methods. Although some effective treatment methods have been explored and achieved certain results, various methods have their own serious shortcomings, forcing their abandonment. How to take effective measures to thoroughly treat phenolic wastewater is crucial to the survival and development of gas stations.

Analyzing the source, production volume, and main pollutant content of phenol-containing wastewater from gas stations, our company has conducted a systematic study on the evaporation and gasification treatment process for this wastewater. We have also conducted numerous experiments and achieved significant results; we have achieved complete incineration of phenolic water, ensuring zero discharge of phenolic water from gas stations.

1. Source and composition of phenol-containing wastewater from gas stations

1.1 Main sources of water in gas

1) Water in coal

2) Water in gasification agent

3) Water brought in during fire detection and rod driving operations

4) Water carried in by the water seal of the ash tray

5) Water carried in by the gas water seal

1.2 Main sources of phenolic water in gas stations

1) Condensate water at the gas intercooler

2) Condensate water discharged from gas booster

3) Condensate water in gas transmission pipeline

2. Treatment of phenol-containing wastewater from gas stations

2.1 Physical characteristics of phenolic wastewater

The main source of phenolic water (excluding tar water) in gas stations is the water condensed from gas after passing through intercoolers and subsequent equipment. This part of water is basically condensate water that comes out when the gas cools down below 100℃.

The phenolic wastewater from the gas station consists of phenols, oils, suspended solids, etc., with monohydric phenols being the main component.

Taking the gasification of a certain bituminous coal in a two-stage furnace gas station as an example, the PH value of the phenol-containing wastewater from the gas station is generally between 7 and 8.5, and its main pollutant indicators are shown in Table 1.

Table 1 Pollutant Indicators of Gas-Containing Phenolic Wastewater

Pollutant Indicator / (mg/l)

Volatile phenol 2128

Oils 2203

COD 5520

Suspended matter 1015

 

2.2 Treatment of phenolic wastewater

After systematic research on the phenolic wastewater from gas stations, our company has decided to adopt incineration to treat the phenolic wastewater from two-stage gasifier gas stations. This process allows phenolic organics to undergo oxidation reactions at a high temperature of around 1100℃, generating CO2 and H2O emissions.

2.3 Process flow diagram of incineration method for phenol-containing wastewater