An example of how to load and run multiple QGIS algorithms outside of QGIS GUI

qgis_model.py

import os
import sys

from qgis.core import *
from PyQt4.QtGui import *

home = os.path.expanduser('~')

sys.path.extend([
    '/usr/share/qgis/python/plugins/processing',
    '/usr/share/qgis/python',
    os.path.join(home, '.qgis2/python'),
    os.path.join(home, '.qgis2/python/plugins'),
    '/usr/share/qgis/python/plugins'
])

import processing
from processing.core.Processing import Processing
from processing.tools import *

app = QApplication([])
QgsApplication.setPrefixPath('/usr', True)
QgsApplication.initQgis()
Processing.initialize()

inp = QgsVectorLayer(os.path.join(home, 'path/to/dataset.gdb/'), 'dataset', 'ogr')

print('Creating Vector Grid')
crs = inp.crs().authid()
extent = ','.join([
    str(inp.extent().xMinimum()),
    str(inp.extent().xMaximum()),
    str(inp.extent().yMinimum()),
    str(inp.extent().yMaximum())
])
gridcellsize = 10000
outputs_QGISVECTORGRID_1 = processing.runalg('qgis:creategrid', 1, extent, gridcellsize, gridcellsize, crs, None)

print('Dissolving')
dissolvefields = ['field1', 'field2']
outputs_QGISDISSOLVE_1 = processing.runalg('qgis:dissolve', inp, False, dissolvefields, None)

print('Clipping')
outputs_QGISCLIP_1 = processing.runalg('qgis:clip', outputs_QGISDISSOLVE_1['OUTPUT'],
                                       outputs_QGISVECTORGRID_1['OUTPUT'], None)

print('Exploding')
outputs_QGISMULTIPARTTOSINGLEPARTS_1 = processing.runalg('qgis:multiparttosingleparts', outputs_QGISCLIP_1['OUTPUT'],
                                                         None)

print('Cleaning')
cleanminarea = 10
cleanthreshold = 1
outputs = processing.runalg('grass7:v.clean', outputs_QGISMULTIPARTTOSINGLEPARTS_1['OUTPUT'], 0, cleanthreshold, extent, cleanthreshold, cleanminarea, None, None)

QgsApplication.exitQgis()
QApplication.exit()

print(outputs)