Variable cross-section integrated waste liquid incineration boiler

The utility model provides a variable cross-section integrated waste liquid incineration boiler which comprises a boiler body, a heat absorption cavity, a connecting cavity and a combustion cavity which are sequentially communicated from top to bottom are arranged in the boiler body, and the cross-sectional area of the heat absorption cavity is larger than that of the combustion cavity. And the cross section area of the combustion cavity is larger than that of the connecting cavity. A connecting pipe set is arranged on the inner side wall of the connecting cavity and comprises a plurality of connecting pipelines and a plurality of arc-shaped arch pipes, the outer side walls of the connecting pipelines are attached to the inner side wall of the connecting cavity, the arc tops of the arc-shaped arch pipes face the interior of the connecting cavity, and a circulation channel is formed between the arc-shaped arch pipes located on the two opposite inner side walls of the connecting cavity. A combustion-supporting