Method for comprehensive treatment of wastewater and sludge gas utilization of cane sugar factory

[0030] Embodiments of the present invention are described below in conjunction with the accompanying drawings: the implementation process of the present invention is as follows: figure 1 As shown in the figure, the bagasse spray water is separated by a mechanical grille and then filtered with a rotating filter screen, and then the steam from the papermaking spray pot is heated to 30-45 ° C and then placed in the adjustment tank; the bagasse washing water will be Alkali recovery Evaporated condensed water to wash the pressed bagasse, filter it with a grid, the bagasse is recycled for papermaking, the wastewater is precipitated, put into the conditioning tank and combined with the bagasse spray water: papermaking alkaline wastewater, filter mud water and paper machine After the waste water is combined, it is put into the adjustment tank and combined with the bagasse spray water and the bagasse washing water. The mixture is sent to the internal circulation anaerobic reactor through the circulation tank for anaerobic reaction, and the obtained biogas is used for paper machine heating after desulfurization, decarbonization, filtration and compression, replacing the current energy of natural gas or electric heating for paper machine heating. The sewage after the reaction in the internal circulation anaerobic reactor is discharged after the aerobic biochemical treatment reaches the standard, and the sludge is used to prepare the organic compound fertilizer.

[0031] like figure 2 The process of biogas purification is that the raw gas from the internal circulation anaerobic reactor is pressurized by a fan, part of it is sent to the boiler as fuel, part of it enters the desulfurization tower to remove hydrogen sulfide, and then is filtered and compressed and sent to the decarbonization workshop , using MDEA solution (MDEA solution concentration is 50%) to carry out physical and chemical absorption decarburization in the absorption tower. put CO 2 falls below 3%, absorbs CO 2 The MDEA solution becomes rich liquid and is sent from the bottom of the column. The purified biogas enters the dryer to remove moisture and obtains qualified product gas, which can be sent to the papermaking workshop.

[0032] rich in CO 2 The rich liquid needs to be regenerated, the CO 2 Recycle after desorption. The rich liquid exchanges heat with the lean liquid from the bottom of the regeneration tower, and is sprayed into the top of the regeneration tower for desorption after heating, and exchanges heat and mass in the reverse direction with the vapor flow from the bottom of the tower. 2 continuously escape from the liquid phase. At the bottom of the tower, the saturated steam of 0.4MPa is used to heat the tower rich liquid through the reboiler to provide the heat energy required for regeneration. The regeneration tower is a packed tower. The regenerated solution becomes lean liquid with a higher temperature. After exchanging heat with the rich liquid, it is pressurized by the lean liquid pump, cooled by water, and sent to the top of the absorption tower to contact with the biogas again for absorption. The desorbed gas from the top of the regeneration tower is mainly CO2, and the gas is directly vented at the top of the desorption tower.

[0033] After the present invention adopts the above-mentioned comprehensive waste water treatment measures, the waste gas, waste water, waste residue and the like discharged in the production process can all meet the environmental protection discharge standard.